为了研究热泵干燥条件下种子内部传质机理,以热泵干燥的白菜种子为研究对象,建立了其非均质动态传质模型,并利用该模型分析热泵恒温连续干燥与间歇干燥条件下种子内部含水率变化规律。研究表明,所建模型能较好的模拟种子含水率的动态变化,模拟值与试验值相关系数为0.9974,相对偏差在±10%以内,模拟精度满足要求;间歇干燥时种子内部含水率更均匀,更有利于种子品质的保证;间歇干燥过程比例系数取1/3、间歇运行周期中运行时间取400s时热泵机组节能近50%。该研究可为热泵干燥技术的应用推广提供参考。
Aimed at studying the moisture diffusion nonhomogeneous dynamic mass transfer model was set mechanism inside the seeds during heat pump drying, a up for cabbage seeds analyze the moisture diffusion in the cabbage seed under conditions of continuous drying with constant temperature and intermittent drying with on/off pulsating of air velocity. Results showed that the simulation results coincided well with experimental data with correlation coefficient of 0.9974 and relative deviation being less than ± 10%. With the heat pump intermittent drying, the moisture distribution inside the cabbage seed was more uniform. With intermittency ratio of 1/3 and on-time in the intermittent drying cycle of 400 s, nearly 50% energy conservation for the heat pump equipment could be achieved during the drying process. This research can provide a reference for application of heat pump drying technique.