Study on coupled heat and moisture transfer in soybean grain pile based on pore scale
Studying the pore structure distribution of grain piles and heat-moisture coupling transfer in the process of drying can provide a theoretical basis for the design of safe grain storage and drying systems.In this study,the soybean packed bed is taken as the research object,and based on the principle of Local Mass and Thermal Non-Equilibrium(LMTNE),a double-diffusion heat and moisture transfer model is established during the drying process of the packed bed.Discrete element method and finite volume method are used to simulate and analyze the porosity and airflow path distribution of the packed bed,as well as the coupling transfer of temperature and moisture.The results indicate that the radial porosity of the packed bed exhibits an oscillating distribution.Due to the wall effect,the porosity near the wall is large but near the central axis is small,which resulted in the tortuosity of the airflow path present an irregular distribution.The double-diffusion heat and moisture transfer model is verified by using the experimental data.The drying rate of the soybean packed bed is mainly affected by the drying air temperature and the moisture content of soybean particles.At drying air temperature of 35,45,55 and 65℃,and relative humidity of 17%,the drying rates of the packed bed are 0.077%/min,0.083%/min,0.089%/min and 0.096%/min(within the first 20 minutes),respectively.
soybeanporosityairflow pathdouble-diffusion heat and moisture transferdrying
万方数据
维普
