Influence of Spiral Airway Structure Parameters of Dual-Airway Diesel Engine on Airway Performance

Numerical simulations of the airflow within the intake system and in-cylinder flow of the D19TCI automotive diesel engine were conducted using Computational Fluid Dynamics (CFD) software. The primary focus of this investigation was to examine the influence of the structural design parameters of the diesel engine's spiral intake manifold on the cylinder's swirl ratio. Through the manipulation of three key structural design parameters of the spiral intake manifold, we explored their impact on the cylinder's swirl ratio. The study utilized the spiral airflow deflection angle (θ), spiral chamber height (H), and eccentricity of the spiral intake manifold (∆a) as the three influential factors, each set at three levels. The swirl ratio and intake volume, representing two essential airflow characteristics, served as the evaluation criteria in an orthogonal experiment and subsequent linear regression analysis.The findings reveal that individually altering the three structural design parameters of the spiral intake manifold to values of -15° for the swirl angle, 6.28 mm for the spiral chamber height, and 3 mm for the eccentricity results in the maximum cylinder swirl ratio. This relationship adheres to the linear regression equation: Swirl Ratio = 0.754 - 0.005Swirl Angle + 0.165Spiral Chamber Height + 0.088*Eccentricity.