Modeling the drying process of fuelbeds of Masson pine needles under different packing ratios based on two-phase models

Background: Modeling the drying process of a fuelbed with an initial moisture content higher than the fiber saturated moisture content, analyzing the influence of the packing ratio of the fuelbed on the drying process, and establishing a prediction model are of great significance to improve the prediction accuracy of the moisture content of fuelbeds and determine when fuelbeds can be ignited after precipitation. We simulated the drying process in five needle beds of Masson pine (Pinus massoniana Lamb.) with different packing ratios. Taking the fiber saturation point (0.35 g·g -1 ) as the threshold, we divided the drying process into two phases. The drying mechanism of each phase was different and has its own drying equation. Compared with the model that does not distinguish the drying process, the prediction effect of the two-phase model was analyzed, and the influence of the fuelbebs packing ratio on the drying process was analyzed. Results: : No matter how the packing ratio changes, the two-phase model can better simulate the drying process, and the average MAE and MRE obtained by the two-phase model decrease by 18.4% and 25.6%, respectively, compared with the one-phase model. The timelag prediction model was established with the packing ratio, and the errors were all within the allowable range, but the prediction effect of the timelag prediction model based on the two phases was better. Conclusions: : It was further demonstrated that considering the packing ratio of the fuelbed and distinguishing the drying process can effectively improve the prediction accuracy of the moisture content of fuelbeds based on the semiphysical method.