Research on an Ultrafine Water Mist Partition Multistage Dust Suppression System in Underground Excavation Tunnel

Research on an Ultrafine Water Mist Partition Multistage Dust Suppression System in Underground Excavation Tunnel | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Research on an Ultrafine Water Mist Partition Multistage Dust Suppression System in Underground Excavation Tunnel Deji Jing, Qisheng Kan, Mingying Dai, Jichuang Ma, Chunhua Bao, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5358013/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Apr, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract A large amount of coal dust is produced in coal mine excavation, which has a serious impact on the working environment and health of underground workers. To address this problem, the spatial and temporal evolution process of coal dust in the excavation tunnel is analyzed via numerical simulation, and an ultrafine water mist partition multistage dust suppression system is developed. The results show that in the original ventilation mode, the air velocity within 5 m from the workface varies greatly, up to 17 m/s. When the airflow impacts the workface, it shifts to the return air side and gradually stabilizes below 2 m/s. Driven by airflow, coal dust gathers around the tunneling machine and diffuses to the rear of the tunnel, the speed increases first and then decreases, and the whole tunnel is filled in 40 s. Within 10 s, the water mist particles cover the whole tunnel at a high speed, capture and settle the coal dust particles, and prevent the further spread of coal dust. After application to the I030409 excavation workface in the Qipanjing Coal Mine, the average reduction efficiency for total dust and respirable dust in the tunnel reached 91.74% and 93.4%, respectively. Therefore, the system successfully achieves partitioning multilevel dust reduction. Health sciences/Health occupations Physical sciences/Engineering Tunnel excavation Coal dust control Wet dust removal Migration law Numerical simulation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 1 Introduction With the development of the global economy, the demand for various energy sources worldwide is increasing. Although the new energy technologies are developed, coal, as a basic energy source, plays a vital role [ 1 – 3 ] . According to the 2024 Statistical Review of World Energy, the world's total coal production in 2023 reached 90.957 billion tons (179.24 EJ), an increase of 3.1% over that in 2022, and global production exceeded 9 billion tons for the first time [ 4 ] . China's total coal output reached 4.71 billion tons, accounting for 51.8% of the world's total coal output. As the world's largest coal production country, China's research and development of mechanized coal equipment has become increasingly intensive. With the wide application of new technology and new materials, the way in which underground workers are exposed to dust in occupational activities has become increasingly complex and diverse, which seriously endangers the health of underground workers [ 5 – 10 ] . According to statistics, the incidence of occupational diseases in China is the highest in the world and is approximately 10 times greater than that in developed countries. Figure 1 shows the number of occupational diseases and the proportion of pneumoconiosis cases in China from 2016 to 2022. In 2016, the number of reported cases of occupational diseases in China exceeded 30,000 for the first time, reaching 31,789, and the number of newly diagnosed occupational diseases and pneumoconiosis cases remained high [ 11 – 14 ] . Notably, high concentrations of dust directly or indirectly lead to the occurrence of underground explosion accidents and fire accidents, causing considerable economic losses to coal mining enterprises and society [ 15 ] . In summary, reducing the dust concentration in tunnel during the coal mine excavation process is an urgent problem. There are two main components of the dust pollution problem in excavation tunnel. First, due to the increase in the degree of mechanization of coal mines, a large force is needed in the excavation process, which leads to greater kinetic energy when dust in the excavation workface is generated. Second, the airflow in excavation tunnel is complex, and dust is difficult to capture [ 16 – 19 ] . Common dust reduction methods include wet and dry dust reduction, and spray dust reduction is the simplest and most effective method of wet dust reduction; thus, most coal mines use spray dust reduction [ 20 – 24 ] . At present, many scholars worldwide have conducted in-depth research on the dust migration law and spray dust reduction technology in excavation tunnel. For example, Hu et al. used a numerical simulation method to study the dust diffusion characteristics of the continuous dust release period (CRP) and stop dust release period (SRP) and obtained the migration law of dust in the driving area of a tunneling machine during the CRP and SRP [ 25 ] . Nie et al. used numerical simulation to analyze the coupling diffusion law of airflow, gas, and dust in excavation tunnel under long-pressure and short-pumping ventilation conditions and explored the best position of an exhaust pipe through experiments [ 26 – 28 ] . Zhou et al. conducted a numerical simulation study on the coupling diffusion law of coal dust and rock dust during the excavation of coal‒rock mixed tunnel and reported that the diffusion law of coal dust and rock dust conforms to the linear equation L D =0.82 T + 11. They proposed cloud-mist dedusting technology to solve the dust pollution problem, and the dust removal efficiency reached more than 75% after field application [ 29 ] . On the basis of the theory of fluid mechanics, Zhang et al. conducted numerical simulation calculations on the airflow-dust field and airflow-droplet field in excavation tunnel, obtained the distribution law of dust and droplets, and studied the effect of multistage atomization [ 30 ] . Although existing research has played an important role in dust reduction in excavation tunnel, the internal space of excavation tunnel is already limited, more mechanical equipment is installed, which affects the workers ability to complete their work, and a variety of dust control methods affect each other and sometimes have side effects. Therefore, in this study, on the basis of spray dust reduction, we propose an ultrafine water mist partition multistage dust suppression system to control dust pollution in excavation tunnel to the greatest extent possible. 2 Mathematical model 2.1 Turbulent flow model The airflow in the excavation tunnel is incompressible, so the Reynolds-averaged Navier-Stokes equations can be used to calculate it [31] . The airflow in the excavation tunnel in this study is a turbulent flow with a large Reynolds number, so the Spalart-Allmaras model, the standard k-ε model and the k-ω model can be selected for calculation. Among them, the standard k-ε model performs better in terms of calculation accuracy and calculation time than the other two models do [32] . Therefore, the standard k-ε model is selected for simulation calculation, and the control equation is as follows [33] : $$\rho \frac{{\partial k}}{{\partial t}}+\rho u \cdot \nabla k=\nabla [(\mu +\frac{{{\mu _T}}}{{{\sigma _k}}})\nabla k]+{P_k} - \rho \varepsilon$$ 1 $$\rho \frac{{\partial \varepsilon }}{{\partial t}}+\rho u \cdot \nabla \varepsilon =\nabla [(\mu +\frac{{{\mu _T}}}{{{\sigma _\varepsilon }}})\nabla \varepsilon ]+{C_{\varepsilon 1}}\frac{\varepsilon }{k}{P_k} - {C_{\varepsilon 2}}\rho \frac{{{\varepsilon ^2}}}{k}$$ 2 Generating item: $${P_k}={\mu _T}[\nabla u:(\nabla u+{(\nabla u)^T}) - \frac{2}{3}{(\nabla \cdot u)^2}] - \frac{2}{3}\rho k\nabla \cdot u$$ 3 Turbulent viscosity: $${\mu _T}=\rho {C_\mu }\frac{{{k^2}}}{\varepsilon }$$ 4 where ρ is the fluid density, kg/m 3 ; µ T is the turbulent viscosity coefficient; k is the turbulent kinetic energy, J; ε is the turbulent dissipation rate; u is the fluid velocity, m/s; µ is the gas dynamic viscosity; and p is the pressure, Pa. The experimental constants are c µ =0.09, σ k = 1, σ k = 1.3, c ε1 =1.44, and c ε2 =1.92. 2.2 Particle tracing model Particle tracing for the fluid flow model is selected for the numerical simulation of coal dust particles and water mist particles in excavation tunnel [34] . The model is based on the motion equation of Newton's second law for simulation calculations. It can define a variety of particle properties and release methods and finally calculate the migration trajectory of particles. Since the coal dust in the excavation tunnel belongs to a kind of dilute particle flow, it is also necessary to add the Stokes drag model [35] . The particle motion equation is as follows: $$\frac{d}{{dt}}({m_p}v)=\sum F$$ 5 Stokes’ drag equation: $${\tau _p}=\frac{{4{\rho _p}d_{p}^{2}}}{{3\mu {C_D}{{\operatorname{Re} }_r}}}$$ 7 $${C_D}=\frac{{24}}{{Re}}(1+0.15R{e^{0.687}})$$ 8 $$Re=\frac{{\rho \left| {u - v} \right|{d_P}}}{{{\mu _g}}}$$ 9 3 Geometric model and boundary conditions 3.1 Geometric model In the numerical simulation, the closer the geometric model is to the field situation, the more realistic the simulation results [ 36 ] . Therefore, to ensure the accuracy of the numerical simulation, according to the actual measurement size of the I040901 excavation workface in the Qipanjing Coal Mine, COMSOL software is used for 1:1 geometric modeling, as shown in Fig. 2 . The compressed air side of the tunnel is defined as the right side, and the return air side is defined as the left side. Taking the lower left side of the tunnel as the origin of the model, the x-axis is established along the direction of the compressed air side of the tunnel, the y-axis is established along the direction opposite the excavation direction, and the z-axis is established along the direction from the tunnel floor heave to the tunnel roof. The geometric model of the excavation tunnel is composed of an EBZ200 cantilever tunneling machine, a pressurized air duct, a KCS-450 wet dust removal fan, a belt conveyor, a full cross-section atomizer device and a cutting head atomizer device. For the excavation tunnel, the length is 40 m, the cross-sectional width is 5 m, and the peak height is 3.8 m; the air duct has a length of 35 m and a diameter of 1 m, and it is located at the top of the tunnel and is 5 m from the workface. The wet dust removal fan is set on the tunneling machine and is connected with an air duct with a diameter of 0.8 m, and the suction port is 3 m from the workface. The belt conveyor is connected with the tunneling machine. There are two full cross-section atomizer devices 15 m and 30 m behind the workface and 3 m from the tunnel floor heave. 3.2 Mesh division and independence test The number of meshes and the quality of the elements play crucial roles in the simulation process, which determines the accuracy and time of the simulation [ 37 ] . When meshing, it is necessary to select the appropriate number of meshes and element quality. When the number of meshes is too large, the calculation time will be too long, but the corresponding calculation accuracy will be greatly improved [ 38 ] . Therefore, grid independence verification is required before simulation to save time and ensure accurate calculations. Using the grid division function of COMSOL software, the Mesh 1, which is a sparse mesh, and Mesh 2 and Mesh 3, which are fine meshes, are used for mesh division. The numbers of meshes are 525,103, 1,025,539, and 2,950,638. The mesh division results are shown in Fig. 3 (a). Since the diffusion of coal dust is affected mainly by the air flow, the air velocity is selected as the research target to verify the independence of the mesh. At the height of the respiratory zone in the center of the tunnel, 8 groups of air velocity were compared with the actual air velocity on site, and the results are shown in Fig. 3 (b). The simulated airflow velocities of the three different meshing methods are compared with the actual airflow velocity in the tunnel. The specific data are shown in Table 1 . The figure shows that as the number of grids increases, the air velocity first clearly changes and then gradually tends to stabilize. The table shows that the airflow velocity of Mesh 1 changes greatly, whereas that of Mesh 2 is the most consistent with the actual airflow velocity. The greater the number of grids is, the closer the air velocity is to the actual value. According to the statistics of Mesh 2, the unit mass skewness of the mesh is shown in Fig. 3 (c). The unit mass is the highest when the unit mass is in the range of 0.6 ~ 0.9, which meets the requirements of the simulation standard. Therefore, Mesh 2 is selected for simulation calculations in this study to save time and ensure accurate calculations. Table 1 Comparison of actual simulated air velocity at different distances. Speed (m/s) Distance (m) 5 m 10 m 15 m 20 m 25 m 30 m 35 m 40 m Actual 2.18 4.91 4.59 4.05 3.66 2.93 2.24 1.97 Mesh 1 2.89 5.87 4.23 3.76 3.57 3.21 2.61 2.25 Mesh 2 2.51 5.09 4.88 4.18 3.63 3.15 2.39 2.19 Mesh 3 2.38 5.18 5.01 4.23 3.79 3.31 2.46 2.21 3.3. Boundary conditions and parameter settings of the numerical simulation According to the actual situation of the excavation tunnel and the field measurement results, the relevant boundary parameters are set, and the COMSOL built-in solver is used for simulation calculations. The outlet of the pressurized air duct and the wet dust removal air is set as the speed inlet, and the outlet is set as the pressure outlet. The settings of the specific boundary parameters are shown in Table 2 . Table 2 Boundary conditions and parameter settings. Type Project Parameter settings General Solver type Stationary/Time-dependent Gravity Z:-g Boundary conditions Entrance boundary condition Inlet velocity Inlet velocity (m/s) 17 Export boundary condition Outlet pressure Turbulent flow, k-ε Fluid density (kg/m 3 ) 1.2 Dynamic viscosity (Pa∙s) 1.79×10 − 5 Diffusion coefficient of a gas molecule (m 2 /s) 2×10 − 5 Temperature (K) 293.15 Wall setting No slip Particle tracing for fluid flow Liquid droplet density (kg/m 3 ) 1.0 Liquid droplet surface tension (N/m) 7.29×10 − 2 Draft model Stokes Turbulent dispersion model Continuous random walk Wall condition Freeze Solid particle density (kg/m 3 ) 2.1 4 Numerical simulation analysis 4.1 Analysis of the airflow field and particle field under different conditions By understanding the airflow field and coal dust particle field under different ventilation conditions in the excavation tunnel, a targeted dust reduction scheme can be proposed. Figure 4 shows the airflow streamline diagram of the wet dust removal fan under different conditions. In the figure, the streamline represents the airflow trajectory, the color represents the airflow velocity, and the arrow represents the airflow direction. The specific analysis is as follows: The temporal and spatial evolution laws of coal dust during the excavation process are explored, and the dust migration law in different states and at different time scales is analyzed to propose a corresponding spray dust isolation method. Figures 5 and 6 show the distributions of coal dust in the unopened and open states of the dust removal fan, respectively. The spheres in the figure represent the coal dust particles, and the color represents their migration speed. Combined with the analysis of the airflow field, the following rules are obtained: (1) At 5 s, the coal dust near the cutting head is affected by airflow blowing from the pressurized air duct and rapidly diffuses 14 m along the return air side of the tunnel. The velocity first increases and then decreases along the diffusion direction, and the maximum velocity reaches 8 m/s at 5 m. (2) At 10 s, the coal dust as the air flow spreads to 25 m, and the migration trend of the coal dust is the same as that at 5 s; however, in the range of 7 ~ 15 m, some coal dust diffuses to the compressed air side and accumulates above the tunneling machine at a lower speed (1 m/s), but no high-concentration coal dust group forms. Moreover, a small amount of coal dust also accumulates near the cab of the tunneling machine. (3) At 20 s, a large amount of coal dust gathers near the cutting head. Driven by the continuous airflow, the coal dust on the return air side diffuses to 34 m, and the part of the coal dust that diffuses to the compressed air side diffuses to the rear of the tunnel to 27 m. At this time, a large amount of dust gathers above the tunneling machine and the belt. (4) At 30 s, the coal dust completely covers the cutting head and basically spreads to the tail of the tunnel. At 50 s, the coal dust fills the entire tunnel. At this time, the coal dust in the rear section of the pressure air side shifts to the return air side because of the influence of the airflow, and this part of the coal dust is basically stable at the tail of the tunnel. From Fig. 6 , the following coal dust particle migration law is obtained: (1) At 5 s, part of the coal dust is pumped away by the dust removal fan, the movement trend of the remaining coal dust is consistent with that when the fan is not open; however, its diffusion trend is obviously curbed, and the diffusion distance is significantly shortened to 10 m. At this time, there is some coal dust on the right side of the cutting head, and there are basically no coal dust particles on the left side. (2) At 10 s, the coal dust is affected by the air flow movement and spreads 18 m along the return air side. A small part of the coal dust in the range of 5 ~ 10 m diffuses to the compressed air side at a speed of 1 m/s, and the amount of coal dust near the cab is significantly reduced by the traction of the fan compared with that of the unopened fan. (3) At 20 s, the coal dust diffuses to 28 m under the continuous airflow, and there is only a small amount of coal dust behind the tunneling machine, which is caused by the combined action of the fan and the compressed air duct. Compared with that of the unopened fan, the diffusion trend of the coal dust in the range of 10 ~ 25 m is obviously curbed. (4) At 30 s, the coal dust diffuses to 30 m, and the coal dust on the return air side diffuses to the compressed air side at a speed of 1 m/s. Coal dust fills the tunnel in 50 s. However, unlike the case with the fan unopened, the coal dust does not gather in the 10 ~ 20 m area, and the amount of coal dust is significantly reduced by the traction of the fan after 15 m. 4.2 Analysis of the law of airflow in an ultrafine water mist partition multistage dust suppression system By analyzing the airflow streamline in the excavation tunnel and the airflow velocity on different ZX cross-sections, the airflow migration law of the ultrafine water mist partition multistage dust suppression system in the closed space of the tunnel is obtained. The three-dimensional spatial distribution of the airflow streamline is shown in Fig. 7 . The streamline in the diagram indicates the airflow trajectory, the arrow indicates the direction of the airflow vector, and the color gradient indicates the airflow velocity. The specific analysis is as follows: (1) The area with a large velocity change is mainly between 0 ~ 10 m, which is affected by the pressure air duct, wet dust removal fan and cutting head atomizer device. At the same time, the velocities of the two full cross-section atomizer devices (15 m and 30 m) also changed significantly, but the airflow velocity attenuated rapidly, and the airflow velocity was basically stable at 1 m/s after 2 m. (2) The high-speed airflow ejected from the air duct impacts the workface, forming a high-speed flow field of 6 ~ 18 m/s in the range of 5 m. When the high-speed airflow collides with the working face, its momentum drops sharply, and a flow field of approximately 6 m/s forms at the bottom of the return air side. The suction outlet of the fan inhales part of the airflow, and at the same time, a flow field area of 6 m/s forms at the exhaust outlet of the fan. (3) The cutting head atomizer device ejects high-speed air flow to wrap the cutting head. The air flow deflects upward and quickly covers the whole working face, which is affected by the suction port of the fan. Full cross-section atomizer device #1 and #2 also shoot high-speed air in the direction of the tunnel floor. When it collides with the tunnel floor, its speed suddenly decreases and stabilizes at approximately 1 m/s, and it migrates to the rear of the tunnel. The streamline diagram shows that the airflow migrating from the workface to the back is divided into two main parts. To further study the airflow migration law inside the tunnel, velocity section cloud images at different positions are intercepted along the Y-axis, as shown in Fig. 8 . The color in the figure represents the airflow velocity. The area with a velocity greater than 6 m/s is the high-speed area, the area with a velocity of 2 ~ 6 m/s is the medium-speed area, and the area with a velocity less than 2 m/s is the low-speed area. Combined with the streamline diagram, the change in airflow velocity inside the tunnel is analyzed. The specific analysis is as follows: (1) According to the velocity section cloud images at Y = 2 m, 3 m and 4 m, there is a high-speed area of 6 ~ 14 m/s in the upper right corner of the tunnel, and the cutting head area is surrounded by a high-speed area of 16 m/s. After the airflow collides with the workface, offset occurs, and a high-speed area of 6 m/s is formed on the right side of the bottom of the tunnel and the return air side. There is also a high-speed area of 6 m/s at the suction port of the fan. (2) According to the velocity section cloud images at Y = 10, 15, and 30 m, the airflow velocity inside the tunnel basically remains stable at approximately 2 m/s, whereas at Y = 10 m, a high-speed area of 6 m/s is observed in the fan outlet area. Moreover, at Y = 15 m and 30 m, airflow with a velocity of 18 m/s is sprayed from the direction of the tunnel floor by the full cross-section atomizer device, but its speed is suddenly reduced and stabilized at 1 m/s. 4.3 Analysis of the law of water mist particles in an ultrafine water mist partition multistage dust suppression system The three-dimensional spatial distribution of water mist particles at different times can be intercepted, as shown in Fig. 9 . The points in the figure represent the position of the water mist particles, and the color represents the velocity of the water mist particles. Combined with the distribution of airflow streamlines, the migration law of water mist particles is analyzed. The results are as follows: (1) At 2 s, the water mist particles surround the cutting head, have a large momentum, and diffuse to the workface at a speed of 8 m/s. Full cross-section atomizer device #1 is affected by the exhaust air of the dust removal fan, the water mist particles diffuse to the rear of the tunnel at a speed of 6 m/s, and the range reaches 9 m. Full cross-section atomizer device #2 is less affected by fan exhaust than #1 and diffuses backward at a speed of 4 m/s, and the range reaches 7 m. At the same time, the water mist particles above the tape shift backward after hitting the tape, but the diffusion range is short. (2) At 6 s, the workface is basically covered by water mist particles. Some water mist particles are inhaled by the fan after they hit the workface, and some water mist particles diffuse along the lateral rear of the return air of the tunnel. The water mist particles generated by full cross-section atomizer device #1 diffuse to the bottom of the tunnel and completely cover the belt conveyor, and the diffusion range reaches 14 m. The migration trend of the water mist particles generated by full cross-section atomizer device #2 is basically the same as that of #1, but the diffusion range is short, at 10 m. (3) At 10 s, many water mist particles accumulate near the cutting head to capture and settle the coal dust generated during tunneling. At the same time, some water mist particles gather on the return air side and spread to the rear of the tunnel, and the speed is stable below 2 m/s; the water mist particles produced by the full cross-face spray completely cover the tape, and a water mist particle film is formed to prevent the diffusion of coal dust particles on the tape. Moreover, the water mist particles generated by the full cross-section spray form two fog curtains, which effectively block dust diffusion. 5 Application of an ultrafine water mist partition multistage dust suppression system 5.1 Research and development of dust removal systems The developed ultrafine water mist partition multistage dust suppression system is composed of a supersonic aerodynamic atomization device (including a full cross-section atomizer device and a cutting head atomizer device) and wet dust removal fan and intelligent control components (including a PLC control box, a dust concentration sensor, an infrared sensor and an electromagnetic ball valve), as shown in Fig. 10 . The nozzle used in the atomizing device is a supersonic water suction aerodynamic atomization nozzle, as shown in Fig. 11 . The nozzle probe has a diameter of 0.8 mm. At a pneumatic pressure of 0.4 MPa, its range can reach 3.8 m, and the atomization angle can reach 85° [ 39 ] . The gas flow rate and water flow rate reached 4.2 ml/m 3 and 93.3 ml/min, respectively. 5.2 Applications in the field According to the actual situation of coal dust generation in the I040901 excavation workface of the Qipanjing Coal Mine [ 40 ] , the ultrafine mist multistage partition dust reduction system is reasonably arranged. The arrangement of the ultrafine water mist partition multistage dust suppression system is shown in Fig. 12 . The cutting head atomizer device is set at the cantilever of the tunneling machine so that the high-speed water mist particles generated by it can wrap around the cutting head and capture and settle the coal dust generated by tunneling. The wet dust removal fan is set on the body of the tunneling machine to collect and filter the coal dust deposited by the spray device of the cutting head to reduce further diffusion of the dust into the tunnel. The full cross-section atomizer device arranges 15 m and 30 m from the working face to generate high-speed water mist particles to block coal dust and capture coal dust particles on the belt conveyor. To measure the dust reduction efficiency of ultrafine water mist partition multistage dust suppression system, five dust test points are arranged in the I040901 excavation workface of the Qipanjing Coal Mine. The arrangement positions are shown in Fig. 13 : at the cutting head, the cab, the transfer point and 2 m behind the two full cross-section atomizer devices. The respiratory zone area at a height of 1.5 m was measured. Dust concentration measurement uses the most accurate dust sampling-drying-weighing method to prevent moisture in the air from affecting the measurement results [ 41 ] . An AKFC-92A dust sampler was used to measure the concentrations of total dust and respirable dust before and after dust reduction. The dust reduction efficiency is shown in Fig. 14 . The average dust reduction efficiencies of total dust and respirable dust are 91.74% and 93.4%, respectively. 6 Conclusion In this study, to address the serious pr1oblem of coal dust pollution in the I030409 excavation workface of the Qipanjing Coal Mine, COMSOL software is used to simulate the distribution of air flow and the temporal and spatial evolution of coal dust in the tunnel via numerical simulation, and according to the simulation results, a scheme for an ultrafine water mist partition multistage dust suppression system is proposed. Moreover, the numerical simulation method is used to calculate the airflow distribution of the dust removal system and the temporal and spatial evolution laws of the water mist particles to verify the effectiveness of the ultrafine water mist partition multistage dust suppression system. The following conclusions are reached: (1) The airflow distribution when the dust removal fan is turned on is roughly the same as that when it is not turned on. The maximum air velocity can reach 17 m/s, and it gradually decreases to 1 m/s after it collides with the workface. The difference is that the vortex appears at 15 m on the compressed air side. The velocity of coal dust first increases and then decreases along the diffusion direction, the maximum velocity reaches 8 m/s, and the whole tunnel is filled at 50 s. (2) The airflow distribution of the dust removal system in the tunnel is more complex. A high-speed zone of 6 ~ 18 m/s forms within 5 m from the working face, and the speed gradually decreases to 1 m/s. However, a high-speed zone of 6 m/s appears at the outlet of the dust removal fan. Moreover, the airflow velocity in the full cross-section spray area decreases from 18 m/s to 1 m/s. (3) The water mist particle field shows that within 10 s, the water mist particles from the cutting head cover the entire workface, and the tunnel is covered by water mist particles under the action of two full cross-section spray. Moreover, the tunnel is divided into three areas, which effectively prevents the coal dust from escaping. (4) After the application of the new dust reduction system in the I030409 excavation workface of the Qipanjing Coal Mine, the average reduction efficiency for total dust and respirable dust reached 91.74% and 93.4%, respectively. The ultrafine water mist partition multistage dust suppression system realizes the partitioning and the step-by-step treatment of coal dust in tunnel. Declarations Corresponding Author E-mail address: [email protected] (Mingying Dai) Author Contribution D.J. and K.Q. wrote the main manuscript text and C.P. proofread the manuscript . K.Q. and D.M. conducted numerical simulation calculations. M.J. and D.P.prepared figures 1-7. D.M. and B.C. prepared figures 8-14. Acknowledgments This work has been funded by the National Special Support Plan for National Outstanding Youth Science Fund Project of National Natural Science Foundation of China (51704146), Natural Science Foundation of Liaoning Province (2020-MS-304), Scientific Research Fund of Liaoning Provincial Education Department (LJKZ0323), General Program of National Natural Science Foundation of China (52474229). Data Availability All data generated or analysed during this study are original and are included in this published article. References W. Nie, F. Liu, H. Peng, J. Li, C. Xu, X. Cha, S. Yi, Optimization of wind-and-water coordinated dust reduction device for coal mine return airway based on CFD technology, Powder Technol. (2024) 119932. https://doi.org/10.1016/j.powtec.2024.119932 Y. Lu, Y. Wang, J. Cheng, Z. Jiang, Y. Chen, J. Chen, Study on air curtain cooperative spray dust removal in heading face based on swirl theory, JECE. 10 (2022) 108892. https://doi.org/10.1016/j.jece.2022.108892 W. Zhou, H. Wang, J. Zhang, F. He, J. Liu, D. Wang, A novel method for reducing the amount of dust produced by roadheaders based on the numerical simulation of coal breakage, Fuel. 343 (2023) 127978. https://doi.org/10.1016/j.fuel.2023.127978 G. Zhou, Y. Liu, Z. Liu, Y. Zhang, Y. Zhu, B. Sun, Y. Ma, Study on the characteristics of compound dust source pollution and foam dust suppression technology in coal mine anchor excavation production, Process Saf. Environ. 186 (2024) 593-611. https://doi.org/10.1016/j.psep.2024.03.119 IU. Din, S. Muhammad, S. Faisal, I. ur Rehman, W. Ali, Heavy metal (loid) s contamination and ecotoxicological hazards in coal, dust, and soil adjacent to coal mining operations, Northwest Pakistan, J. Geochem. Explor. 256 (2024) 107332. https://doi.org/10.1016/j.gexplo.2023.107332 C. Xu, R. Song, G. Zhou, H. Jiang, B. Sun, Construction of an occupational-dust hazard testing platform: An experimental study on the deposition mechanisms, Adv. Powder Technol. 34 (2023) 104027. https://doi.org/10.1016/j.apt.2023.104027 Y. Shangguan, X. Zhuang, X. Querol, B. Li, N. Moreno, P. Trechera, PC. Sola, G. Uzu, J. Li, Physicochemical characteristics and oxidative potential of size-segregated respirable coal mine dust: Implications for potentially hazardous agents and health risk assessment. Int. J. Coal Geol. 282 (2024) 104433. https://doi.org/10.1016/j.coal.2023.104433 H. Han, Comprehensive Dust Removal and Dustproof Technology in Coal Mine Roadway Excavation, Energy and Energy Conservation. 07 (2024) 168-170+174. https://doi.org/10.16643/j.cnki.14-1360/td.2024.07.076b C. Xu, Y. Song, R. Song, G. Zhou, H. Zhang, L. Li, L. Zheng, Q. Zhang, Y. Wang, Study on the deposition rates of inhaled dust in respiratory tract by anchor excavation driver during coal mining, Adv. Powder Technol. 35 (2024) 104541. https://doi.org/10.1016/j.apt.2024.104541 T. Du, W. Nie, D. Chen, Z. Xiu, B. Yang, Q. Liu, L. Guo, CFD modeling of coal dust migration in an 8.8-meter-high fully mechanized mining face. Energy, 212 (2020) 118616. https: // doi.org /10.1016 /j.energy. 2020. 118616 C. Xu, W. Nie, H. Peng, F. Liu, S. Yi, X. Cha, J. Li, FI. Mwabaima, Numerical simulation of the effect of a wind-assisted spraying device during continuous mining, Powder Technol. 428 (2023) 118803. https://doi.org/10.1016/j.powtec.2023.118803 X. Lu, C. Shen, Y. Xing, H. Zhang, C. Wang, G. Shi, M. Wang, The spatial diffusion rule and pollution region of disorganized dust in the excavation roadway at different roadheader cutting positions, Powder Technol. 396 (2022) 167-180. https://doi.org/10.1016/j.powtec.2021.10.033 X. Lyu, Y. Qiao, D. Yuan, Z. Zhang, W. Zuo, J. Hua, Y. Wang, L. Zhang, Investigation and CFD simulation of coal dust explosion accident in confined space: A case study of Gaohe Coal Mine Ventilation Air Methane oxidation power plant, Fire Safety J. 149 (2024) 104237. https://doi.org/10.1016/j.firesaf.2024.104237 G. Zhou, J. Ding, Y. Ma, S. Li, M. Zhang, Synthesis and performance characterization of a novel wetting cementing agent for dust control during conveyor transport in coal mines, Powder Technol. 360 (2020) 165-176. https://doi.org/10.1016/j.powtec.2019.10.003 Q. Liu, W. Cheng, L. Liu, Y. Hua, L. Guo, W. Nie, Research on the control law of dust in the main ventilation system in excavated tunnels for cleaner production, Build. Environ. 205 (2021) 108282. https://doi.org/10.1016/j.buildenv.2021.108282 N. Liu, X. Wu, E. Deng, Y. Ni, W. Yang, G. Li, Dust diffusion laws during partition excavation by boom-type roadheader in a metro tunnel, Tunn. Underge. Sp. Technol. 141 (2023) 105382. https://doi.org/10.1016/j.tust.2023.105382 C. Hou, H. Yu, Y. Ye, X. Yang, Y. Wang, W. Cheng, Study on dust pollution characteristics and optimal dust control parameters during tunnel excavation by CFD simulation, Adv. Powder Technol. 34 (2023) 104217. https://doi.org/10.1016/j.apt.2023.104217 W. Nie, N. Sun, Q. Liu, L. Guo, Q. Xue, C. Liu, W. Niu, Comparative study of dust pollution and air quality of tunnelling anchor integrated machine working face with different ventilation, Tunn. Underge. Sp. Technol. 122 (2022) 104377. https://doi.org/10.1016/j.tust.2022.104377 Y. Cao, Y. Xiao, Z. Wang, Q. Li, C. Shu,X. Jing, S. Liang, Recent progress and perspectives on coal dust sources, transport, hazards, and controls in underground mines, Process Saf. Environ. (2024). https://doi.org/10.1016/j.psep.2024.04.095 P. Wang, G. Lu, Y. Xu, Research Status and Prospects of Coal Mine Dust and Prevention and Control Technology, Modern Mining. 39 (2023) 8-13. https://doi.org/10.3969/j.issn.1674-6082.2023.11.003 J. Yao, Exploration of Coal Mine Dust Prevention and Control Measures, Energy and Energy Conservation. 05 (2024) 145-147. https://doi.org/10.16643/j.cnki.14-1360/td.2024.05.059 J. Hou, S. Li, S. Hu, H. Cheng, M. Han, C. Gui, Q. Guo, L. Yuan, F. Zhou, Research and application of self-powered induction spray dust removal system for long-distance belt conveying in underground coal mines, Process Saf. Environ. 176 (2023) 131-139. https://doi.org/10.1016/j.psep.2023.06.009 J. Wang, Research progress on coal mine dust hazard and its prevention and control technology [J]. Coal Chemical Industry, 52 (2024) 53-56+72. https://doi.org/10.19889/j.cnki.10059598.2024.04.013 S. Hu, Y. Gao, G. Feng, Y. Huang, H. Shao, Q. Liao, F. Hu, Characteristics of dust distributions and dust control measures around road-header drivers in mining excavation roadways, Particuology. 58 (2021) 268-275. https://doi.org/10.1016/j.partic.2021.03.017 W. Nie, Y. Cai, L. Wang, Q. Liu, C. Jiang, Y. Hua, C. Cheng, H. Zhang, Coupled diffusion law of windflow-gas-dust in tunnel energy extraction processes and the location of optimal pollution control exhaust duct, Energy. 304 (2024) 132145. https://doi.org/10.1016/j.energy.2024.132145 W. Nie, Y. Cai, L. Wang, Q. Liu, C. Jiang, Y. Hua, L. Guo, C. Cheng, H. Zhang Study of spatiotemporal evolution of coupled airflow-gas-dust multi-field diffusion at low-gas tunnel, Sci. Total Environ. 928 (2024) 172428. https://doi.org/10.1016/j.scitotenv.2024.172428 W. Nie, X. Cai, H. Peng, Q. Ma, Q. Liu, Y. Hua, L. Guo, L. Cheng, N.Sun, Q. Bao, Distribution characteristics of an airflow-dust mixture and quantitative analysis of the dust absorption effect during tunnel sub-regional coal cutting, Process Saf. Environ. 164 (2022) 319-334. https://doi.org/10.1016/j.psep.2022.05.068 G. Zhou, B. Jing, Q. Meng, Y. Liu, W. Yang, B. Sun, Study on coupling diffusion of composite dust and cloud-mist dedust technology in fully mechanized driving face of mixed coal-rock roadway, Adv. Powder Technol. 34 (2023) 103911. https://doi.org/10.1016/j.apt.2022.103911 G. Zhang, G. Zhou, L. Zhang, B. Sun, N. Wang, H. Yang, W. Liu, Numerical simulation and engineering application of multistage atomization dustfall at a fully mechanized excavation face, Tunn. Undergr. Sp. Technol. 104 (2020) 103540. https://doi.org/10.1016/j.tust.2020.103540 D. Jing, Z. Li, S. Ge, T. Zhang, X. Meng, X. Jia, Research on the mechanism of multilayer spiral fog screen dust removal at the comprehensive excavation face, Plos one. 17 (2022) e0266671. https://doi.org/10.1371/journal.pone.0266671 J. John, EA. Pane, BM. Suyitno, GHNN. Rahayu, D. Rhakasywi, A. Suwandi, Computational fluid dynamics simulation of the turbulence models in the tested section on wind tunnel, Ain Shams Eng. J. 11 (2020) 1201-1209. https://doi.org/10.1016/j.asej.2020.02.012 S. Ren, D. Jing, S. Ge, M. Ma, MWA. Asad, P. Chang, Research and development of vortex suction dedusting device based on multi-factor horizontal response surface method, J. Clean. Prod. 442 (2024) 140916. https://doi.org/10.1016/j.jclepro.2024.140916 D. Jing, H. Liu, T. Zhang, S. Ge, X. Meng, S. Ren, Q. Zhang, Numerical simulation and experimental study on dust suppression by supersonic spiral aerodynamic atomization, Journal of Safety and Environment. 23 (2023): 4343-4350. https://doi.org/10.13637/j.issn.1009-6094.2022.2017 L. Tong, Y. Xu, X. Wang, H. Yang, K. Ma, CFD-DEM numerical study on coal dust pollution law of coal transfer point in underground coal mine, Safety in Coal Mines. 52 (2021) 188-192+200. https://doi.org/10.13347/j.cnki.mkaq.2021.05.034 W Jiang, X Xu, Z Wen, L Wei, Applying the similarity theory to model dust dispersion during coal-mine tunneling, Process Saf. Environ. 148 (2021) 415-427. https://doi.org/10.1016/j.psep.2020.10.026 M. Qiao, J. Roberts, T. Ren, J. Hines, J. Wu, Dispersion and migration characteristics of multisource respirable dust in development panels during tunnelling processes, Tunn. Undergr. Sp. Technol. 148 (2024) 105778. https://doi.org/10.1016/j.tust.2024.105778 Y. Xiao, X. Yang, Z. Wang, Q. Li, J. Deng, Diffusion characteristics of coal dust associated with different ventilation methods in underground excavation tunnel, Process Saf. Environ. 184 (2024) 1177-1191. https://doi.org/10.1016/j.psep.2024.02.065 T. Zhang, D. Jing, S. Ge, J. wang, S. Ren, X. Meng, Supersonic siphon suction water aerodynamic atomization in dust removal. Journal of China Coal Society, 46 (2021) 3912-3921. https://doi.org/10.13225/j.cnki.jccs.2021.0198 J. Lou, Y. Guo, Q. Kan, F. Jiang, T. Zhang, Research on multi-layer spiral spray dust removal technology in heading face. Safety in Coal Mines, 55 (2024) 94-99. https://doi.org/10.13347/j.cnki.mkaq.20221800 J. Zhang, L. Sun, G. Zhang, H. Tao, D. Jiang, H. Zhang, Research on Influence of Different Cutting Positions in Coal Roadway on Law of Dust Transport and Diffusion. Coal Technology, 42 (2023) 177-181. https://doi.org/10.13301/j.cnki.ct.2023.08.037 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Apr, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 27 Nov, 2024 Reviews received at journal 27 Nov, 2024 Reviews received at journal 23 Nov, 2024 Reviewers agreed at journal 20 Nov, 2024 Reviewers agreed at journal 14 Nov, 2024 Reviewers invited by journal 14 Nov, 2024 Editor assigned by journal 14 Nov, 2024 Editor invited by journal 14 Nov, 2024 Submission checks completed at journal 13 Nov, 2024 First submitted to journal 29 Oct, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5358013","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":383647690,"identity":"56c5555d-9c57-45f3-940c-f5136bacb9e7","order_by":0,"name":"Deji Jing","email":"","orcid":"","institution":"Liaoning Technical University","correspondingAuthor":false,"prefix":"","firstName":"Deji","middleName":"","lastName":"Jing","suffix":""},{"id":383647691,"identity":"b1f3b114-7856-4bf6-93f9-2d361eca579d","order_by":1,"name":"Qisheng Kan","email":"","orcid":"","institution":"Liaoning Technical 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4","display":"","copyAsset":false,"role":"figure","size":1605036,"visible":true,"origin":"","legend":"\u003cp\u003eSpatial distribution of the airflow streamline diagram under different ventilation conditions.\u003c/p\u003e","description":"","filename":"Fig.4..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/a185fb734a4bdd78fc15f796.png"},{"id":70662728,"identity":"8d6f5adf-f009-49bd-aa66-c7f76b4fcd61","added_by":"auto","created_at":"2024-12-05 11:13:14","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1305309,"visible":true,"origin":"","legend":"\u003cp\u003eDiagram of the spatiotemporal diffusion of coal dust in the dust removal fan closed state.\u003c/p\u003e","description":"","filename":"Fig.5..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/2f147dd7149b44ddba9daf02.png"},{"id":70662966,"identity":"7c78b7da-58f1-4e5e-adb5-4cc6fba1755c","added_by":"auto","created_at":"2024-12-05 11:21:14","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":991977,"visible":true,"origin":"","legend":"\u003cp\u003eDiagram of the spatiotemporal diffusion of coal dust in the dust removal fan operating state.\u003c/p\u003e","description":"","filename":"Fig.6..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/e1a740dc6a30c1b926be6715.png"},{"id":70662795,"identity":"e8ea1281-27fe-448c-a5d1-4f15f17db9d1","added_by":"auto","created_at":"2024-12-05 11:13:20","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":2165506,"visible":true,"origin":"","legend":"\u003cp\u003eSpatial distribution of the airflow streamline diagram of the dust suppression system.\u003c/p\u003e","description":"","filename":"Fig.7..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/cd7d668884f6e19376369e10.png"},{"id":70662723,"identity":"a314cd34-0254-48f7-9d9c-765d4b9789f9","added_by":"auto","created_at":"2024-12-05 11:13:14","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":577469,"visible":true,"origin":"","legend":"\u003cp\u003eCross-sectional views of the velocity at different positions in the Y-axis direction.\u003c/p\u003e","description":"","filename":"Fig.8..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/b56a51fc5bc209b88a550fb8.png"},{"id":70661716,"identity":"74fc7ff9-3ca9-420b-abc3-d92cb17795f6","added_by":"auto","created_at":"2024-12-05 11:05:14","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":2656908,"visible":true,"origin":"","legend":"\u003cp\u003eDiagram of the spatiotemporal diffusion of water mist particles.\u003c/p\u003e","description":"","filename":"Fig.9..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/1c7f05036c01818c5f826f2d.png"},{"id":70661742,"identity":"8a3246cf-86f3-4191-8b13-591805e2d692","added_by":"auto","created_at":"2024-12-05 11:05:16","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":2105461,"visible":true,"origin":"","legend":"\u003cp\u003eComponents of the ultrafine water mist partition multistage dust suppression system.\u003c/p\u003e","description":"","filename":"Fig.10..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/67dcc63bf7a738fce7e2e1b0.png"},{"id":70664462,"identity":"c3c20a86-9d05-4847-8813-d4f53ba44a9b","added_by":"auto","created_at":"2024-12-05 11:37:14","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":1200093,"visible":true,"origin":"","legend":"\u003cp\u003eSupersonic water suction aerodynamic atomization nozzle.\u003c/p\u003e","description":"","filename":"Fig.11..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/dd401df189bf45938c1713a2.png"},{"id":70662730,"identity":"57d4592b-361f-4b78-83ea-46a1da93e4c4","added_by":"auto","created_at":"2024-12-05 11:13:14","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":1967000,"visible":true,"origin":"","legend":"\u003cp\u003eField application of an ultrafine water mist partition multistage dust suppression system.\u003c/p\u003e","description":"","filename":"Fig.12..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/1e154237ea5623881148f495.png"},{"id":70661801,"identity":"fab944fb-d38f-4ee0-b346-08f6ea46c0b4","added_by":"auto","created_at":"2024-12-05 11:05:22","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":123205,"visible":true,"origin":"","legend":"\u003cp\u003eLocations of the measuring points.\u003c/p\u003e","description":"","filename":"Fig.13..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/b07049d8a3d178b7d9d6101a.png"},{"id":70664180,"identity":"1af86647-ef3b-4b54-a755-48c3d949e3ad","added_by":"auto","created_at":"2024-12-05 11:29:14","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":95542,"visible":true,"origin":"","legend":"\u003cp\u003eRates of (a) total dust reduction and (b) respiratory dust reduction.\u003c/p\u003e","description":"","filename":"Fig.14..png","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/ef6cf1bf29720134525f9b6e.png"},{"id":81987670,"identity":"939e093c-3c1f-45f8-acd6-1152e8b224b7","added_by":"auto","created_at":"2025-05-05 16:04:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":19561350,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5358013/v1/9161e1a9-d41c-4684-a1bd-76b8aea6cfea.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Research on an Ultrafine Water Mist Partition Multistage Dust Suppression System in Underground Excavation Tunnel","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eWith the development of the global economy, the demand for various energy sources worldwide is increasing. Although the new energy technologies are developed, coal, as a basic energy source, plays a vital role\u003csup\u003e[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. According to the 2024 Statistical Review of World Energy, the world's total coal production in 2023 reached 90.957\u0026nbsp;billion tons (179.24 EJ), an increase of 3.1% over that in 2022, and global production exceeded 9\u0026nbsp;billion tons for the first time\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. China's total coal output reached 4.71\u0026nbsp;billion tons, accounting for 51.8% of the world's total coal output. As the world's largest coal production country, China's research and development of mechanized coal equipment has become increasingly intensive. With the wide application of new technology and new materials, the way in which underground workers are exposed to dust in occupational activities has become increasingly complex and diverse, which seriously endangers the health of underground workers\u003csup\u003e[\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. According to statistics, the incidence of occupational diseases in China is the highest in the world and is approximately 10 times greater than that in developed countries. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the number of occupational diseases and the proportion of pneumoconiosis cases in China from 2016 to 2022. In 2016, the number of reported cases of occupational diseases in China exceeded 30,000 for the first time, reaching 31,789, and the number of newly diagnosed occupational diseases and pneumoconiosis cases remained high\u003csup\u003e[\u003cspan additionalcitationids=\"CR12 CR13\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. Notably, high concentrations of dust directly or indirectly lead to the occurrence of underground explosion accidents and fire accidents, causing considerable economic losses to coal mining enterprises and society\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn summary, reducing the dust concentration in tunnel during the coal mine excavation process is an urgent problem. There are two main components of the dust pollution problem in excavation tunnel. First, due to the increase in the degree of mechanization of coal mines, a large force is needed in the excavation process, which leads to greater kinetic energy when dust in the excavation workface is generated. Second, the airflow in excavation tunnel is complex, and dust is difficult to capture\u003csup\u003e[\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e. Common dust reduction methods include wet and dry dust reduction, and spray dust reduction is the simplest and most effective method of wet dust reduction; thus, most coal mines use spray dust reduction\u003csup\u003e[\u003cspan additionalcitationids=\"CR21 CR22 CR23\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e. At present, many scholars worldwide have conducted in-depth research on the dust migration law and spray dust reduction technology in excavation tunnel.\u003c/p\u003e \u003cp\u003eFor example, Hu et al. used a numerical simulation method to study the dust diffusion characteristics of the continuous dust release period (CRP) and stop dust release period (SRP) and obtained the migration law of dust in the driving area of a tunneling machine during the CRP and SRP\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. Nie et al. used numerical simulation to analyze the coupling diffusion law of airflow, gas, and dust in excavation tunnel under long-pressure and short-pumping ventilation conditions and explored the best position of an exhaust pipe through experiments\u003csup\u003e[\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e. Zhou et al. conducted a numerical simulation study on the coupling diffusion law of coal dust and rock dust during the excavation of coal‒rock mixed tunnel and reported that the diffusion law of coal dust and rock dust conforms to the linear equation \u003cem\u003eL\u003c/em\u003e\u003csub\u003e\u003cem\u003eD\u003c/em\u003e\u003c/sub\u003e=0.82\u003cem\u003eT\u003c/em\u003e\u0026thinsp;+\u0026thinsp;11. They proposed cloud-mist dedusting technology to solve the dust pollution problem, and the dust removal efficiency reached more than 75% after field application\u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. On the basis of the theory of fluid mechanics, Zhang et al. conducted numerical simulation calculations on the airflow-dust field and airflow-droplet field in excavation tunnel, obtained the distribution law of dust and droplets, and studied the effect of multistage atomization\u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAlthough existing research has played an important role in dust reduction in excavation tunnel, the internal space of excavation tunnel is already limited, more mechanical equipment is installed, which affects the workers ability to complete their work, and a variety of dust control methods affect each other and sometimes have side effects. Therefore, in this study, on the basis of spray dust reduction, we propose an ultrafine water mist partition multistage dust suppression system to control dust pollution in excavation tunnel to the greatest extent possible.\u003c/p\u003e"},{"header":"2 Mathematical model","content":"\u003cdiv id=\"Sec3\"\u003e\n \u003ch2\u003e2.1 Turbulent flow model\u003c/h2\u003e\n \u003cp\u003eThe airflow in the excavation tunnel is incompressible, so the Reynolds-averaged Navier-Stokes equations can be used to calculate it\u003csup\u003e[31]\u003c/sup\u003e. The airflow in the excavation tunnel in this study is a turbulent flow with a large Reynolds number, so the Spalart-Allmaras model, the standard k-\u0026epsilon; model and the k-\u0026omega; model can be selected for calculation. Among them, the standard k-\u0026epsilon; model performs better in terms of calculation accuracy and calculation time than the other two models do\u003csup\u003e[32]\u003c/sup\u003e. Therefore, the standard k-\u0026epsilon; model is selected for simulation calculation, and the control equation is as follows\u003csup\u003e[33]\u003c/sup\u003e:\u003c/p\u003e\n \u003cdiv id=\"Equ1\"\u003e\n \u003cdiv id=\"FileID_Equ1\" name=\"EquationSource\"\u003e$$\\rho \\frac{{\\partial k}}{{\\partial t}}+\\rho u \\cdot \\nabla k=\\nabla [(\\mu +\\frac{{{\\mu _T}}}{{{\\sigma _k}}})\\nabla k]+{P_k} - \\rho \\varepsilon$$\u003c/div\u003e\n \u003cdiv\u003e1\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Equ2\"\u003e\n \u003cdiv id=\"FileID_Equ2\" name=\"EquationSource\"\u003e$$\\rho \\frac{{\\partial \\varepsilon }}{{\\partial t}}+\\rho u \\cdot \\nabla \\varepsilon =\\nabla [(\\mu +\\frac{{{\\mu _T}}}{{{\\sigma _\\varepsilon }}})\\nabla \\varepsilon ]+{C_{\\varepsilon 1}}\\frac{\\varepsilon }{k}{P_k} - {C_{\\varepsilon 2}}\\rho \\frac{{{\\varepsilon ^2}}}{k}$$\u003c/div\u003e\n \u003cdiv\u003e2\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eGenerating item:\u003c/p\u003e\n \u003cdiv id=\"Equ3\"\u003e\n \u003cdiv id=\"FileID_Equ3\" name=\"EquationSource\"\u003e$${P_k}={\\mu _T}[\\nabla u:(\\nabla u+{(\\nabla u)^T}) - \\frac{2}{3}{(\\nabla \\cdot u)^2}] - \\frac{2}{3}\\rho k\\nabla \\cdot u$$\u003c/div\u003e\n \u003cdiv\u003e3\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eTurbulent viscosity:\u003c/p\u003e\n \u003cdiv id=\"Equ4\"\u003e\n \u003cdiv id=\"FileID_Equ4\" name=\"EquationSource\"\u003e$${\\mu _T}=\\rho {C_\\mu }\\frac{{{k^2}}}{\\varepsilon }$$\u003c/div\u003e\n \u003cdiv\u003e4\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003ewhere \u003cem\u003e\u0026rho;\u003c/em\u003e is the fluid density, kg/m\u003csup\u003e3\u003c/sup\u003e; \u003cem\u003e\u0026micro;\u003c/em\u003e\u003csub\u003e\u003cem\u003eT\u003c/em\u003e\u003c/sub\u003e is the turbulent viscosity coefficient; \u003cem\u003ek\u003c/em\u003e is the turbulent kinetic energy, J; \u003cem\u003e\u0026epsilon;\u003c/em\u003e is the turbulent dissipation rate; \u003cem\u003eu\u003c/em\u003e is the fluid velocity, m/s; \u003cem\u003e\u0026micro;\u003c/em\u003e is the gas dynamic viscosity; and \u003cem\u003ep\u003c/em\u003e is the pressure, Pa. The experimental constants are \u003cem\u003ec\u003c/em\u003e\u003csub\u003e\u003cem\u003e\u0026micro;\u003c/em\u003e\u003c/sub\u003e=0.09, \u003cem\u003e\u0026sigma;\u003c/em\u003e\u003csub\u003e\u003cem\u003ek\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1, \u003cem\u003e\u0026sigma;\u003c/em\u003e\u003csub\u003e\u003cem\u003ek\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1.3, \u003cem\u003ec\u003c/em\u003e\u003csub\u003e\u003cem\u003e\u0026epsilon;1\u003c/em\u003e\u003c/sub\u003e=1.44, and \u003cem\u003ec\u003c/em\u003e\u003csub\u003e\u003cem\u003e\u0026epsilon;2\u003c/em\u003e\u003c/sub\u003e=1.92.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\"\u003e\n \u003ch2\u003e2.2 Particle tracing model\u003c/h2\u003e\n \u003cp\u003eParticle tracing for the fluid flow model is selected for the numerical simulation of coal dust particles and water mist particles in excavation tunnel\u003csup\u003e[34]\u003c/sup\u003e. The model is based on the motion equation of Newton\u0026apos;s second law for simulation calculations. It can define a variety of particle properties and release methods and finally calculate the migration trajectory of particles. Since the coal dust in the excavation tunnel belongs to a kind of dilute particle flow, it is also necessary to add the Stokes drag model\u003csup\u003e[35]\u003c/sup\u003e. The particle motion equation is as follows:\u003c/p\u003e\n \u003cdiv id=\"Equ5\"\u003e\n \u003cdiv id=\"FileID_Equ5\" name=\"EquationSource\"\u003e$$\\frac{d}{{dt}}({m_p}v)=\\sum F$$\u003c/div\u003e\n \u003cdiv\u003e5\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eStokes\u0026rsquo; drag equation:\u003c/p\u003e\n \u003cdiv id=\"Equ6\"\u003e\n \u003cdiv id=\"FileID_Equ6\" name=\"EquationSource\"\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"647\" height=\"45\"\u003e\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Equ7\"\u003e\n \u003cdiv id=\"FileID_Equ7\" name=\"EquationSource\"\u003e$${\\tau _p}=\\frac{{4{\\rho _p}d_{p}^{2}}}{{3\\mu {C_D}{{\\operatorname{Re} }_r}}}$$\u003c/div\u003e\n \u003cdiv\u003e7\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Equ8\"\u003e\n \u003cdiv id=\"FileID_Equ8\" name=\"EquationSource\"\u003e$${C_D}=\\frac{{24}}{{Re}}(1+0.15R{e^{0.687}})$$\u003c/div\u003e\n \u003cdiv\u003e8\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Equ9\"\u003e\n \u003cdiv id=\"FileID_Equ9\" name=\"EquationSource\"\u003e$$Re=\\frac{{\\rho \\left| {u - v} \\right|{d_P}}}{{{\\mu _g}}}$$\u003c/div\u003e\n \u003cdiv\u003e9\u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"3 Geometric model and boundary conditions","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Geometric model\u003c/h2\u003e \u003cp\u003eIn the numerical simulation, the closer the geometric model is to the field situation, the more realistic the simulation results\u003csup\u003e[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. Therefore, to ensure the accuracy of the numerical simulation, according to the actual measurement size of the I040901 excavation workface in the Qipanjing Coal Mine, COMSOL software is used for 1:1 geometric modeling, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The compressed air side of the tunnel is defined as the right side, and the return air side is defined as the left side. Taking the lower left side of the tunnel as the origin of the model, the x-axis is established along the direction of the compressed air side of the tunnel, the y-axis is established along the direction opposite the excavation direction, and the z-axis is established along the direction from the tunnel floor heave to the tunnel roof. The geometric model of the excavation tunnel is composed of an EBZ200 cantilever tunneling machine, a pressurized air duct, a KCS-450 wet dust removal fan, a belt conveyor, a full cross-section atomizer device and a cutting head atomizer device. For the excavation tunnel, the length is 40 m, the cross-sectional width is 5 m, and the peak height is 3.8 m; the air duct has a length of 35 m and a diameter of 1 m, and it is located at the top of the tunnel and is 5 m from the workface. The wet dust removal fan is set on the tunneling machine and is connected with an air duct with a diameter of 0.8 m, and the suction port is 3 m from the workface. The belt conveyor is connected with the tunneling machine. There are two full cross-section atomizer devices 15 m and 30 m behind the workface and 3 m from the tunnel floor heave.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Mesh division and independence test\u003c/h2\u003e \u003cp\u003eThe number of meshes and the quality of the elements play crucial roles in the simulation process, which determines the accuracy and time of the simulation\u003csup\u003e[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/sup\u003e. When meshing, it is necessary to select the appropriate number of meshes and element quality. When the number of meshes is too large, the calculation time will be too long, but the corresponding calculation accuracy will be greatly improved\u003csup\u003e[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/sup\u003e. Therefore, grid independence verification is required before simulation to save time and ensure accurate calculations.\u003c/p\u003e \u003cp\u003eUsing the grid division function of COMSOL software, the Mesh 1, which is a sparse mesh, and Mesh 2 and Mesh 3, which are fine meshes, are used for mesh division. The numbers of meshes are 525,103, 1,025,539, and 2,950,638. The mesh division results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a). Since the diffusion of coal dust is affected mainly by the air flow, the air velocity is selected as the research target to verify the independence of the mesh. At the height of the respiratory zone in the center of the tunnel, 8 groups of air velocity were compared with the actual air velocity on site, and the results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e (b). The simulated airflow velocities of the three different meshing methods are compared with the actual airflow velocity in the tunnel. The specific data are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The figure shows that as the number of grids increases, the air velocity first clearly changes and then gradually tends to stabilize. The table shows that the airflow velocity of Mesh 1 changes greatly, whereas that of Mesh 2 is the most consistent with the actual airflow velocity. The greater the number of grids is, the closer the air velocity is to the actual value. According to the statistics of Mesh 2, the unit mass skewness of the mesh is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(c). The unit mass is the highest when the unit mass is in the range of 0.6\u0026thinsp;~\u0026thinsp;0.9, which meets the requirements of the simulation standard. Therefore, Mesh 2 is selected for simulation calculations in this study to save time and ensure accurate calculations.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of actual simulated air velocity at different distances.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSpeed (m/s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"8\" nameend=\"c9\" namest=\"c2\"\u003e \u003cp\u003eDistance (m)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e20 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e35 m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e40 m\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eActual\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1.97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMesh 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMesh 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2.19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMesh 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Boundary conditions and parameter settings of the numerical simulation\u003c/h2\u003e \u003cp\u003eAccording to the actual situation of the excavation tunnel and the field measurement results, the relevant boundary parameters are set, and the COMSOL built-in solver is used for simulation calculations. The outlet of the pressurized air duct and the wet dust removal air is set as the speed inlet, and the outlet is set as the pressure outlet. The settings of the specific boundary parameters are shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBoundary conditions and parameter settings.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eType\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eProject\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eParameter settings\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGeneral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolver type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStationary/Time-dependent\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGravity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eZ:-g\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eBoundary conditions\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEntrance boundary condition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eInlet velocity\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInlet velocity (m/s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eExport boundary condition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOutlet pressure\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eTurbulent flow, k-ε\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFluid density (kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDynamic viscosity (Pa∙s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.79\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiffusion coefficient of a gas molecule (m\u003csup\u003e2\u003c/sup\u003e/s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTemperature (K)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e293.15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWall setting\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo slip\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003eParticle tracing for fluid flow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLiquid droplet density (kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLiquid droplet surface tension (N/m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.29\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDraft model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStokes\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTurbulent dispersion model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eContinuous random walk\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWall condition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFreeze\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolid particle density (kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4 Numerical simulation analysis","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Analysis of the airflow field and particle field under different conditions\u003c/h2\u003e \u003cp\u003eBy understanding the airflow field and coal dust particle field under different ventilation conditions in the excavation tunnel, a targeted dust reduction scheme can be proposed. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the airflow streamline diagram of the wet dust removal fan under different conditions. In the figure, the streamline represents the airflow trajectory, the color represents the airflow velocity, and the arrow represents the airflow direction. The specific analysis is as follows:\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe temporal and spatial evolution laws of coal dust during the excavation process are explored, and the dust migration law in different states and at different time scales is analyzed to propose a corresponding spray dust isolation method. Figures\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e show the distributions of coal dust in the unopened and open states of the dust removal fan, respectively. The spheres in the figure represent the coal dust particles, and the color represents their migration speed.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCombined with the analysis of the airflow field, the following rules are obtained:\u003c/p\u003e \u003cp\u003e(1) At 5 s, the coal dust near the cutting head is affected by airflow blowing from the pressurized air duct and rapidly diffuses 14 m along the return air side of the tunnel. The velocity first increases and then decreases along the diffusion direction, and the maximum velocity reaches 8 m/s at 5 m.\u003c/p\u003e \u003cp\u003e(2) At 10 s, the coal dust as the air flow spreads to 25 m, and the migration trend of the coal dust is the same as that at 5 s; however, in the range of 7\u0026thinsp;~\u0026thinsp;15 m, some coal dust diffuses to the compressed air side and accumulates above the tunneling machine at a lower speed (1 m/s), but no high-concentration coal dust group forms. Moreover, a small amount of coal dust also accumulates near the cab of the tunneling machine.\u003c/p\u003e \u003cp\u003e(3) At 20 s, a large amount of coal dust gathers near the cutting head. Driven by the continuous airflow, the coal dust on the return air side diffuses to 34 m, and the part of the coal dust that diffuses to the compressed air side diffuses to the rear of the tunnel to 27 m. At this time, a large amount of dust gathers above the tunneling machine and the belt.\u003c/p\u003e \u003cp\u003e(4) At 30 s, the coal dust completely covers the cutting head and basically spreads to the tail of the tunnel. At 50 s, the coal dust fills the entire tunnel. At this time, the coal dust in the rear section of the pressure air side shifts to the return air side because of the influence of the airflow, and this part of the coal dust is basically stable at the tail of the tunnel.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFrom Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, the following coal dust particle migration law is obtained:\u003c/p\u003e \u003cp\u003e(1) At 5 s, part of the coal dust is pumped away by the dust removal fan, the movement trend of the remaining coal dust is consistent with that when the fan is not open; however, its diffusion trend is obviously curbed, and the diffusion distance is significantly shortened to 10 m. At this time, there is some coal dust on the right side of the cutting head, and there are basically no coal dust particles on the left side.\u003c/p\u003e \u003cp\u003e(2) At 10 s, the coal dust is affected by the air flow movement and spreads 18 m along the return air side. A small part of the coal dust in the range of 5\u0026thinsp;~\u0026thinsp;10 m diffuses to the compressed air side at a speed of 1 m/s, and the amount of coal dust near the cab is significantly reduced by the traction of the fan compared with that of the unopened fan.\u003c/p\u003e \u003cp\u003e(3) At 20 s, the coal dust diffuses to 28 m under the continuous airflow, and there is only a small amount of coal dust behind the tunneling machine, which is caused by the combined action of the fan and the compressed air duct. Compared with that of the unopened fan, the diffusion trend of the coal dust in the range of 10\u0026thinsp;~\u0026thinsp;25 m is obviously curbed.\u003c/p\u003e \u003cp\u003e(4) At 30 s, the coal dust diffuses to 30 m, and the coal dust on the return air side diffuses to the compressed air side at a speed of 1 m/s. Coal dust fills the tunnel in 50 s. However, unlike the case with the fan unopened, the coal dust does not gather in the 10\u0026thinsp;~\u0026thinsp;20 m area, and the amount of coal dust is significantly reduced by the traction of the fan after 15 m.\u003c/p\u003e \u003cp\u003e \u003cb\u003e4.2 Analysis of the law of airflow in an ultrafine water mist partition multistage dust suppression system\u003c/b\u003e \u003c/p\u003e \u003cp\u003eBy analyzing the airflow streamline in the excavation tunnel and the airflow velocity on different ZX cross-sections, the airflow migration law of the ultrafine water mist partition multistage dust suppression system in the closed space of the tunnel is obtained. The three-dimensional spatial distribution of the airflow streamline is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. The streamline in the diagram indicates the airflow trajectory, the arrow indicates the direction of the airflow vector, and the color gradient indicates the airflow velocity. The specific analysis is as follows:\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(1) The area with a large velocity change is mainly between 0\u0026thinsp;~\u0026thinsp;10 m, which is affected by the pressure air duct, wet dust removal fan and cutting head atomizer device. At the same time, the velocities of the two full cross-section atomizer devices (15 m and 30 m) also changed significantly, but the airflow velocity attenuated rapidly, and the airflow velocity was basically stable at 1 m/s after 2 m.\u003c/p\u003e \u003cp\u003e(2) The high-speed airflow ejected from the air duct impacts the workface, forming a high-speed flow field of 6\u0026thinsp;~\u0026thinsp;18 m/s in the range of 5 m. When the high-speed airflow collides with the working face, its momentum drops sharply, and a flow field of approximately 6 m/s forms at the bottom of the return air side. The suction outlet of the fan inhales part of the airflow, and at the same time, a flow field area of 6 m/s forms at the exhaust outlet of the fan.\u003c/p\u003e \u003cp\u003e(3) The cutting head atomizer device ejects high-speed air flow to wrap the cutting head. The air flow deflects upward and quickly covers the whole working face, which is affected by the suction port of the fan. Full cross-section atomizer device #1 and #2 also shoot high-speed air in the direction of the tunnel floor. When it collides with the tunnel floor, its speed suddenly decreases and stabilizes at approximately 1 m/s, and it migrates to the rear of the tunnel.\u003c/p\u003e \u003cp\u003eThe streamline diagram shows that the airflow migrating from the workface to the back is divided into two main parts. To further study the airflow migration law inside the tunnel, velocity section cloud images at different positions are intercepted along the Y-axis, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. The color in the figure represents the airflow velocity. The area with a velocity greater than 6 m/s is the high-speed area, the area with a velocity of 2\u0026thinsp;~\u0026thinsp;6 m/s is the medium-speed area, and the area with a velocity less than 2 m/s is the low-speed area. Combined with the streamline diagram, the change in airflow velocity inside the tunnel is analyzed. The specific analysis is as follows:\u003c/p\u003e \u003cp\u003e(1) According to the velocity section cloud images at Y\u0026thinsp;=\u0026thinsp;2 m, 3 m and 4 m, there is a high-speed area of 6\u0026thinsp;~\u0026thinsp;14 m/s in the upper right corner of the tunnel, and the cutting head area is surrounded by a high-speed area of 16 m/s. After the airflow collides with the workface, offset occurs, and a high-speed area of 6 m/s is formed on the right side of the bottom of the tunnel and the return air side. There is also a high-speed area of 6 m/s at the suction port of the fan.\u003c/p\u003e \u003cp\u003e(2) According to the velocity section cloud images at Y\u0026thinsp;=\u0026thinsp;10, 15, and 30 m, the airflow velocity inside the tunnel basically remains stable at approximately 2 m/s, whereas at Y\u0026thinsp;=\u0026thinsp;10 m, a high-speed area of 6 m/s is observed in the fan outlet area. Moreover, at Y\u0026thinsp;=\u0026thinsp;15 m and 30 m, airflow with a velocity of 18 m/s is sprayed from the direction of the tunnel floor by the full cross-section atomizer device, but its speed is suddenly reduced and stabilized at 1 m/s.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e4.3 Analysis of the law of water mist particles in an ultrafine water mist partition multistage dust suppression system\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe three-dimensional spatial distribution of water mist particles at different times can be intercepted, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e. The points in the figure represent the position of the water mist particles, and the color represents the velocity of the water mist particles. Combined with the distribution of airflow streamlines, the migration law of water mist particles is analyzed. The results are as follows:\u003c/p\u003e \u003cp\u003e(1) At 2 s, the water mist particles surround the cutting head, have a large momentum, and diffuse to the workface at a speed of 8 m/s. Full cross-section atomizer device #1 is affected by the exhaust air of the dust removal fan, the water mist particles diffuse to the rear of the tunnel at a speed of 6 m/s, and the range reaches 9 m. Full cross-section atomizer device #2 is less affected by fan exhaust than #1 and diffuses backward at a speed of 4 m/s, and the range reaches 7 m. At the same time, the water mist particles above the tape shift backward after hitting the tape, but the diffusion range is short.\u003c/p\u003e \u003cp\u003e(2) At 6 s, the workface is basically covered by water mist particles. Some water mist particles are inhaled by the fan after they hit the workface, and some water mist particles diffuse along the lateral rear of the return air of the tunnel. The water mist particles generated by full cross-section atomizer device #1 diffuse to the bottom of the tunnel and completely cover the belt conveyor, and the diffusion range reaches 14 m. The migration trend of the water mist particles generated by full cross-section atomizer device #2 is basically the same as that of #1, but the diffusion range is short, at 10 m.\u003c/p\u003e \u003cp\u003e(3) At 10 s, many water mist particles accumulate near the cutting head to capture and settle the coal dust generated during tunneling. At the same time, some water mist particles gather on the return air side and spread to the rear of the tunnel, and the speed is stable below 2 m/s; the water mist particles produced by the full cross-face spray completely cover the tape, and a water mist particle film is formed to prevent the diffusion of coal dust particles on the tape. Moreover, the water mist particles generated by the full cross-section spray form two fog curtains, which effectively block dust diffusion.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"5 Application of an ultrafine water mist partition multistage dust suppression system","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e5.1 Research and development of dust removal systems\u003c/h2\u003e \u003cp\u003eThe developed ultrafine water mist partition multistage dust suppression system is composed of a supersonic aerodynamic atomization device (including a full cross-section atomizer device and a cutting head atomizer device) and wet dust removal fan and intelligent control components (including a PLC control box, a dust concentration sensor, an infrared sensor and an electromagnetic ball valve), as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e. The nozzle used in the atomizing device is a supersonic water suction aerodynamic atomization nozzle, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e. The nozzle probe has a diameter of 0.8 mm. At a pneumatic pressure of 0.4 MPa, its range can reach 3.8 m, and the atomization angle can reach 85\u0026deg;\u003csup\u003e[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/sup\u003e. The gas flow rate and water flow rate reached 4.2 ml/m\u003csup\u003e3\u003c/sup\u003e and 93.3 ml/min, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e5.2 Applications in the field\u003c/h2\u003e \u003cp\u003eAccording to the actual situation of coal dust generation in the I040901 excavation workface of the Qipanjing Coal Mine\u003csup\u003e[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/sup\u003e, the ultrafine mist multistage partition dust reduction system is reasonably arranged. The arrangement of the ultrafine water mist partition multistage dust suppression system is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e. The cutting head atomizer device is set at the cantilever of the tunneling machine so that the high-speed water mist particles generated by it can wrap around the cutting head and capture and settle the coal dust generated by tunneling. The wet dust removal fan is set on the body of the tunneling machine to collect and filter the coal dust deposited by the spray device of the cutting head to reduce further diffusion of the dust into the tunnel. The full cross-section atomizer device arranges 15 m and 30 m from the working face to generate high-speed water mist particles to block coal dust and capture coal dust particles on the belt conveyor.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo measure the dust reduction efficiency of ultrafine water mist partition multistage dust suppression system, five dust test points are arranged in the I040901 excavation workface of the Qipanjing Coal Mine. The arrangement positions are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e: at the cutting head, the cab, the transfer point and 2 m behind the two full cross-section atomizer devices. The respiratory zone area at a height of 1.5 m was measured. Dust concentration measurement uses the most accurate dust sampling-drying-weighing method to prevent moisture in the air from affecting the measurement results\u003csup\u003e[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/sup\u003e. An AKFC-92A dust sampler was used to measure the concentrations of total dust and respirable dust before and after dust reduction. The dust reduction efficiency is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e. The average dust reduction efficiencies of total dust and respirable dust are 91.74% and 93.4%, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"6 Conclusion","content":"\u003cp\u003eIn this study, to address the serious pr1oblem of coal dust pollution in the I030409 excavation workface of the Qipanjing Coal Mine, COMSOL software is used to simulate the distribution of air flow and the temporal and spatial evolution of coal dust in the tunnel via numerical simulation, and according to the simulation results, a scheme for an ultrafine water mist partition multistage dust suppression system is proposed. Moreover, the numerical simulation method is used to calculate the airflow distribution of the dust removal system and the temporal and spatial evolution laws of the water mist particles to verify the effectiveness of the ultrafine water mist partition multistage dust suppression system. The following conclusions are reached:\u003c/p\u003e \u003cp\u003e(1) The airflow distribution when the dust removal fan is turned on is roughly the same as that when it is not turned on. The maximum air velocity can reach 17 m/s, and it gradually decreases to 1 m/s after it collides with the workface. The difference is that the vortex appears at 15 m on the compressed air side. The velocity of coal dust first increases and then decreases along the diffusion direction, the maximum velocity reaches 8 m/s, and the whole tunnel is filled at 50 s.\u003c/p\u003e \u003cp\u003e(2) The airflow distribution of the dust removal system in the tunnel is more complex. A high-speed zone of 6\u0026thinsp;~\u0026thinsp;18 m/s forms within 5 m from the working face, and the speed gradually decreases to 1 m/s. However, a high-speed zone of 6 m/s appears at the outlet of the dust removal fan. Moreover, the airflow velocity in the full cross-section spray area decreases from 18 m/s to 1 m/s.\u003c/p\u003e \u003cp\u003e(3) The water mist particle field shows that within 10 s, the water mist particles from the cutting head cover the entire workface, and the tunnel is covered by water mist particles under the action of two full cross-section spray. Moreover, the tunnel is divided into three areas, which effectively prevents the coal dust from escaping.\u003c/p\u003e \u003cp\u003e(4) After the application of the new dust reduction system in the I030409 excavation workface of the Qipanjing Coal Mine, the average reduction efficiency for total dust and respirable dust reached 91.74% and 93.4%, respectively. The ultrafine water mist partition multistage dust suppression system realizes the partitioning and the step-by-step treatment of coal dust in tunnel.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCorresponding Author\u003c/h2\u003e \u003cp\u003eE-mail address: [email protected] (Mingying Dai)\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eD.J. and K.Q. wrote the main manuscript text and C.P. proofread the manuscript . K.Q. and D.M. conducted numerical simulation calculations. M.J. and D.P.prepared figures 1-7. D.M. and B.C. prepared figures 8-14.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThis work has been funded by the National Special Support Plan for National Outstanding Youth Science Fund Project of National Natural Science Foundation of China (51704146), Natural Science Foundation of Liaoning Province (2020-MS-304), Scientific Research Fund of Liaoning Provincial Education Department (LJKZ0323), General Program of National Natural Science Foundation of China (52474229).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll data generated or analysed during this study are original and are included in this published article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eW. Nie, F. Liu, H. Peng, J. Li, C. Xu, X. Cha, S. Yi, Optimization of wind-and-water coordinated dust reduction device for coal mine return airway based on CFD technology, Powder Technol. (2024) 119932. https://doi.org/10.1016/j.powtec.2024.119932\u003c/li\u003e\n\u003cli\u003eY. Lu, Y. Wang, J. Cheng, Z. Jiang, Y. Chen, J. Chen, Study on air curtain cooperative spray dust removal in heading face based on swirl theory, JECE. 10 (2022) 108892. https://doi.org/10.1016/j.jece.2022.108892\u003c/li\u003e\n\u003cli\u003eW. Zhou, H. Wang, J. Zhang, F. He, J. Liu, D. Wang, A novel method for reducing the amount of dust produced by roadheaders based on the numerical simulation of coal breakage, Fuel. 343 (2023) 127978. https://doi.org/10.1016/j.fuel.2023.127978\u003c/li\u003e\n\u003cli\u003e\u0026lt;Statistical Review of World Energy 2024.pdf\u0026gt;\u003c/li\u003e\n\u003cli\u003eG. Zhou, Y. Liu, Z. Liu, Y. Zhang, Y. Zhu, B. Sun, Y. Ma, Study on the characteristics of compound dust source pollution and foam dust suppression technology in coal mine anchor excavation production, Process Saf. Environ. 186 (2024) 593-611. https://doi.org/10.1016/j.psep.2024.03.119\u003c/li\u003e\n\u003cli\u003eIU. Din, S. Muhammad, S. Faisal, I. ur Rehman, W. Ali, Heavy metal (loid) s contamination and ecotoxicological hazards in coal, dust, and soil adjacent to coal mining operations, Northwest Pakistan, J. Geochem. Explor. 256 (2024) 107332. https://doi.org/10.1016/j.gexplo.2023.107332\u003c/li\u003e\n\u003cli\u003eC. Xu, R. Song, G. Zhou, H. Jiang, B. Sun, Construction of an occupational-dust hazard testing platform: An experimental study on the deposition mechanisms, Adv. Powder Technol. 34 (2023) 104027. https://doi.org/10.1016/j.apt.2023.104027\u003c/li\u003e\n\u003cli\u003eY. Shangguan, X. Zhuang, X. Querol, B. Li, N. Moreno, P. Trechera, PC. Sola, G. Uzu, J. Li, Physicochemical characteristics and oxidative potential of size-segregated respirable coal mine dust: Implications for potentially hazardous agents and health risk assessment. Int. J. Coal Geol. 282 (2024) 104433. https://doi.org/10.1016/j.coal.2023.104433\u003c/li\u003e\n\u003cli\u003eH. Han, Comprehensive Dust Removal and Dustproof Technology in Coal Mine Roadway Excavation, Energy and Energy Conservation. 07 (2024) 168-170+174. https://doi.org/10.16643/j.cnki.14-1360/td.2024.07.076b \u003c/li\u003e\n\u003cli\u003eC. Xu, Y. Song, R. Song, G. Zhou, H. Zhang, L. Li, L. Zheng, Q. Zhang, Y. Wang, Study on the deposition rates of inhaled dust in respiratory tract by anchor excavation driver during coal mining, Adv. Powder Technol. 35 (2024) 104541. https://doi.org/10.1016/j.apt.2024.104541\u003c/li\u003e\n\u003cli\u003eT. Du, W. Nie, D. Chen, Z. Xiu, B. Yang, Q. Liu, L. Guo, CFD modeling of coal dust migration in an 8.8-meter-high fully mechanized mining face. Energy, 212 (2020) 118616. https: // doi.org /10.1016 /j.energy. 2020. 118616 \u003c/li\u003e\n\u003cli\u003eC. Xu, W. Nie, H. Peng, F. Liu, S. Yi, X. Cha, J. Li, FI. Mwabaima, Numerical simulation of the effect of a wind-assisted spraying device during continuous mining, Powder Technol. 428 (2023) 118803. https://doi.org/10.1016/j.powtec.2023.118803\u003c/li\u003e\n\u003cli\u003eX. Lu, C. Shen, Y. Xing, H. Zhang, C. Wang, G. Shi, M. Wang, The spatial diffusion rule and pollution region of disorganized dust in the excavation roadway at different roadheader cutting positions, Powder Technol. 396 (2022) 167-180. https://doi.org/10.1016/j.powtec.2021.10.033\u003c/li\u003e\n\u003cli\u003eX. Lyu, Y. Qiao, D. Yuan, Z. Zhang, W. Zuo, J. Hua, Y. Wang, L. Zhang, Investigation and CFD simulation of coal dust explosion accident in confined space: A case study of Gaohe Coal Mine Ventilation Air Methane oxidation power plant, Fire Safety J. 149 (2024) 104237. https://doi.org/10.1016/j.firesaf.2024.104237\u003c/li\u003e\n\u003cli\u003eG. Zhou, J. Ding, Y. Ma, S. Li, M. Zhang, Synthesis and performance characterization of a novel wetting cementing agent for dust control during conveyor transport in coal mines, Powder Technol. 360 (2020) 165-176. https://doi.org/10.1016/j.powtec.2019.10.003\u003c/li\u003e\n\u003cli\u003eQ. Liu, W. Cheng, L. Liu, Y. Hua, L. Guo, W. Nie, Research on the control law of dust in the main ventilation system in excavated tunnels for cleaner production, Build. Environ. 205 (2021) 108282. https://doi.org/10.1016/j.buildenv.2021.108282\u003c/li\u003e\n\u003cli\u003eN. Liu, X. Wu, E. Deng, Y. Ni, W. Yang, G. Li, Dust diffusion laws during partition excavation by boom-type roadheader in a metro tunnel, Tunn. Underge. Sp. Technol. 141 (2023) 105382. https://doi.org/10.1016/j.tust.2023.105382\u003c/li\u003e\n\u003cli\u003eC. Hou, H. Yu, Y. Ye, X. Yang, Y. Wang, W. Cheng, Study on dust pollution characteristics and optimal dust control parameters during tunnel excavation by CFD simulation, Adv. Powder Technol. 34 (2023) 104217. https://doi.org/10.1016/j.apt.2023.104217\u003c/li\u003e\n\u003cli\u003eW. Nie, N. Sun, Q. Liu, L. Guo, Q. Xue, C. Liu, W. Niu, Comparative study of dust pollution and air quality of tunnelling anchor integrated machine working face with different ventilation, Tunn. Underge. Sp. Technol. 122 (2022) 104377. https://doi.org/10.1016/j.tust.2022.104377\u003c/li\u003e\n\u003cli\u003eY. Cao, Y. Xiao, Z. Wang, Q. Li, C. Shu,X. Jing, S. Liang, Recent progress and perspectives on coal dust sources, transport, hazards, and controls in underground mines, Process Saf. Environ. (2024). https://doi.org/10.1016/j.psep.2024.04.095 \u003c/li\u003e\n\u003cli\u003eP. Wang, G. Lu, Y. Xu, Research Status and Prospects of Coal Mine Dust and Prevention and Control Technology, Modern Mining. 39 (2023) 8-13. https://doi.org/10.3969/j.issn.1674-6082.2023.11.003 \u003c/li\u003e\n\u003cli\u003eJ. Yao, Exploration of Coal Mine Dust Prevention and Control Measures, Energy and Energy Conservation. 05 (2024) 145-147. https://doi.org/10.16643/j.cnki.14-1360/td.2024.05.059 \u003c/li\u003e\n\u003cli\u003eJ. Hou, S. Li, S. Hu, H. Cheng, M. Han, C. Gui, Q. Guo, L. Yuan, F. Zhou, Research and application of self-powered induction spray dust removal system for long-distance belt conveying in underground coal mines, Process Saf. Environ. 176 (2023) 131-139. https://doi.org/10.1016/j.psep.2023.06.009\u003c/li\u003e\n\u003cli\u003eJ. Wang, Research progress on coal mine dust hazard and its prevention and control technology [J]. Coal Chemical Industry, 52 (2024) 53-56+72. https://doi.org/10.19889/j.cnki.10059598.2024.04.013 \u003c/li\u003e\n\u003cli\u003eS. Hu, Y. Gao, G. Feng, Y. Huang, H. Shao, Q. Liao, F. Hu, Characteristics of dust distributions and dust control measures around road-header drivers in mining excavation roadways, Particuology. 58 (2021) 268-275. https://doi.org/10.1016/j.partic.2021.03.017\u003c/li\u003e\n\u003cli\u003eW. Nie, Y. Cai, L. Wang, Q. Liu, C. Jiang, Y. Hua, C. Cheng, H. Zhang, Coupled diffusion law of windflow-gas-dust in tunnel energy extraction processes and the location of optimal pollution control exhaust duct, Energy. 304 (2024) 132145. https://doi.org/10.1016/j.energy.2024.132145\u003c/li\u003e\n\u003cli\u003eW. Nie, Y. Cai, L. Wang, Q. Liu, C. Jiang, Y. Hua, L. Guo, C. Cheng, H. Zhang Study of spatiotemporal evolution of coupled airflow-gas-dust multi-field diffusion at low-gas tunnel, Sci. Total Environ. 928 (2024) 172428. https://doi.org/10.1016/j.scitotenv.2024.172428\u003c/li\u003e\n\u003cli\u003eW. Nie, X. Cai, H. Peng, Q. Ma, Q. Liu, Y. Hua, L. Guo, L. Cheng, N.Sun, Q. Bao, Distribution characteristics of an airflow-dust mixture and quantitative analysis of the dust absorption effect during tunnel sub-regional coal cutting, Process Saf. Environ. 164 (2022) 319-334. https://doi.org/10.1016/j.psep.2022.05.068\u003c/li\u003e\n\u003cli\u003eG. Zhou, B. Jing, Q. Meng, Y. Liu, W. Yang, B. Sun, Study on coupling diffusion of composite dust and cloud-mist dedust technology in fully mechanized driving face of mixed coal-rock roadway, Adv. Powder Technol. 34 (2023) 103911. https://doi.org/10.1016/j.apt.2022.103911\u003c/li\u003e\n\u003cli\u003eG. Zhang, G. Zhou, L. Zhang, B. Sun, N. Wang, H. Yang, W. Liu, Numerical simulation and engineering application of multistage atomization dustfall at a fully mechanized excavation face, Tunn. Undergr. Sp. Technol. 104 (2020) 103540. https://doi.org/10.1016/j.tust.2020.103540\u003c/li\u003e\n\u003cli\u003eD. Jing, Z. Li, S. Ge, T. Zhang, X. Meng, X. Jia, Research on the mechanism of multilayer spiral fog screen dust removal at the comprehensive excavation face, Plos one. 17 (2022) e0266671. https://doi.org/10.1371/journal.pone.0266671\u003c/li\u003e\n\u003cli\u003eJ. John, EA. Pane, BM. Suyitno, GHNN. Rahayu, D. Rhakasywi, A. Suwandi, Computational fluid dynamics simulation of the turbulence models in the tested section on wind tunnel, Ain Shams Eng. J. 11 (2020) 1201-1209. https://doi.org/10.1016/j.asej.2020.02.012 \u003c/li\u003e\n\u003cli\u003eS. Ren, D. Jing, S. Ge, M. Ma, MWA. Asad, P. Chang, Research and development of vortex suction dedusting device based on multi-factor horizontal response surface method, J. Clean. Prod. 442 (2024) 140916. https://doi.org/10.1016/j.jclepro.2024.140916\u003c/li\u003e\n\u003cli\u003eD. Jing, H. Liu, T. Zhang, S. Ge, X. Meng, S. Ren, Q. Zhang, Numerical simulation and experimental study on dust suppression by supersonic spiral aerodynamic atomization, Journal of Safety and Environment. 23 (2023): 4343-4350. https://doi.org/10.13637/j.issn.1009-6094.2022.2017 \u003c/li\u003e\n\u003cli\u003eL. Tong, Y. Xu, X. Wang, H. Yang, K. Ma, CFD-DEM numerical study on coal dust pollution law of coal transfer point in underground coal mine, Safety in Coal Mines. 52 (2021) 188-192+200. https://doi.org/10.13347/j.cnki.mkaq.2021.05.034 \u003c/li\u003e\n\u003cli\u003eW Jiang, X Xu, Z Wen, L Wei, Applying the similarity theory to model dust dispersion during coal-mine tunneling, Process Saf. Environ. 148 (2021) 415-427. https://doi.org/10.1016/j.psep.2020.10.026 \u003c/li\u003e\n\u003cli\u003eM. Qiao, J. Roberts, T. Ren, J. Hines, J. Wu, Dispersion and migration characteristics of multisource respirable dust in development panels during tunnelling processes, Tunn. Undergr. Sp. Technol. 148 (2024) 105778. https://doi.org/10.1016/j.tust.2024.105778\u003c/li\u003e\n\u003cli\u003eY. Xiao, X. Yang, Z. Wang, Q. Li, J. Deng, Diffusion characteristics of coal dust associated with different ventilation methods in underground excavation tunnel, Process Saf. Environ. 184 (2024) 1177-1191. https://doi.org/10.1016/j.psep.2024.02.065\u003c/li\u003e\n\u003cli\u003eT. Zhang, D. Jing, S. Ge, J. wang, S. Ren, X. Meng, Supersonic siphon suction water aerodynamic atomization in dust removal. Journal of China Coal Society, 46 (2021) 3912-3921. https://doi.org/10.13225/j.cnki.jccs.2021.0198 \u003c/li\u003e\n\u003cli\u003eJ. Lou, Y. Guo, Q. Kan, F. Jiang, T. Zhang, Research on multi-layer spiral spray dust removal technology in heading face. Safety in Coal Mines, 55 (2024) 94-99. https://doi.org/10.13347/j.cnki.mkaq.20221800 \u003c/li\u003e\n\u003cli\u003eJ. Zhang, L. Sun, G. Zhang, H. Tao, D. Jiang, H. Zhang, Research on Influence of Different Cutting Positions in Coal Roadway on Law of Dust Transport and Diffusion. Coal Technology, 42 (2023) 177-181. https://doi.org/10.13301/j.cnki.ct.2023.08.037\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Tunnel excavation, Coal dust control, Wet dust removal, Migration law, Numerical simulation","lastPublishedDoi":"10.21203/rs.3.rs-5358013/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5358013/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA large amount of coal dust is produced in coal mine excavation, which has a serious impact on the working environment and health of underground workers. To address this problem, the spatial and temporal evolution process of coal dust in the excavation tunnel is analyzed via numerical simulation, and an ultrafine water mist partition multistage dust suppression system is developed. The results show that in the original ventilation mode, the air velocity within 5 m from the workface varies greatly, up to 17 m/s. When the airflow impacts the workface, it shifts to the return air side and gradually stabilizes below 2 m/s. Driven by airflow, coal dust gathers around the tunneling machine and diffuses to the rear of the tunnel, the speed increases first and then decreases, and the whole tunnel is filled in 40 s. Within 10 s, the water mist particles cover the whole tunnel at a high speed, capture and settle the coal dust particles, and prevent the further spread of coal dust. After application to the I030409 excavation workface in the Qipanjing Coal Mine, the average reduction efficiency for total dust and respirable dust in the tunnel reached 91.74% and 93.4%, respectively. Therefore, the system successfully achieves partitioning multilevel dust reduction.\u003c/p\u003e","manuscriptTitle":"Research on an Ultrafine Water Mist Partition Multistage Dust Suppression System in Underground Excavation Tunnel","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-05 11:05:08","doi":"10.21203/rs.3.rs-5358013/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-11-28T04:23:04+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-11-27T06:33:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-11-23T14:01:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"115141665658508977801808896254984578036","date":"2024-11-20T13:18:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"249142885224147328827437601489395666229","date":"2024-11-15T02:13:37+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-11-14T13:18:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-11-14T13:16:43+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-11-14T09:39:11+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-11-13T06:24:54+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-10-30T03:34:29+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"bebdecb6-3e4b-49ff-b54e-2395a3aa021f","owner":[],"postedDate":"December 5th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":40868790,"name":"Health sciences/Health occupations"},{"id":40868791,"name":"Physical sciences/Engineering"}],"tags":[],"updatedAt":"2025-05-05T15:59:06+00:00","versionOfRecord":{"articleIdentity":"rs-5358013","link":"https://doi.org/10.1038/s41598-025-99689-z","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-04-28 15:57:08","publishedOnDateReadable":"April 28th, 2025"},"versionCreatedAt":"2024-12-05 11:05:08","video":"","vorDoi":"10.1038/s41598-025-99689-z","vorDoiUrl":"https://doi.org/10.1038/s41598-025-99689-z","workflowStages":[]},"version":"v1","identity":"rs-5358013","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5358013","identity":"rs-5358013","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}