菜豆种子薄层干燥的潜力分析

为探讨薄层物料脱水过程颗粒内部水分的迁移机理，考虑物料的非均质性及水分扩散系数在干燥过程的变化，利用扩散方程模型通过有限差分法数值模拟了菜豆种子的干燥过程，分析了物料内部温度场及湿度场的相互影响。结果表明，种皮是种子干燥过程最主要的传质阻力之一，菜豆种子子叶层的扩散系数是种皮层的3．2倍。根据物料颗粒内部的湿度分布，匹配一定的温度场，能够显著加快脱水过程，可以认为这是干燥极限过程，在一定程度上说明了强化、优化传热传质的方向与干燥潜力。

Analysis of Drying Potentiality for Thin Layer Drying of Vegetable Seed

To investigate the internal moisture transfer mechanism of seed granule during the thin layer drying process by numerical calculating with the method of finite difference, the internal moisture diffusion model was used to for modeling the drying process of kidney bean seed. Result shows that seed coat is the main mass transfer resistance in the drying process, and the moisture diffusivity of the cotyledon layer is 3.2 times as high as that of the seed coat layer. If the internal temperature distribution profiles was properly matched with it internal moisture content distribution profiles within seed granule, the fastest drying process could be obtained, which might be considered as ＂limiting drying process＂ and to some extent, indicated the direction and potentiality of optimization and enhancement of heat and mass transfer.