【摘要】 研究了菜豆种子在红外固定床干燥过程中 ,种皮结构的变化及种皮对干燥动力学特性的影响 .运用描述种子干燥过程特征的内部水分扩散模型 ,确定了种子的水分扩散系数 ,模型与实验数据相吻合 .研究表明 ,无种皮时种子的水分扩散系数为有种皮时的 1.6 7倍 ,种子子叶层的扩散系数是种皮层的 3.2倍 ,种皮是种子干燥过程中主要的传质阻力之一 ,也是优化传热与传质的关键 .更多还原

【Abstract】 Kidney bean seed was dried in a laboratory scale fixed bed. The effect of seed coat on drying dynamic characteristics and the changes of seed coat structure were investigated. A mathematical model was established to simulate the drying process and determine the moisture diffusivity. Numerical results agree well with the experimental data. The average moisture diffusivity of the seed with separated coat is 1.67 times larger than that of the seed with coat, and the moisture diffusivity of seed cotyledon is 3.2 times larger than that of the seed coat. It is proved that the seed coat is the most main resistance of mass transfer and is also one of the key points of the optimization of heat and mass transfer for seed drying.更多还原