为了解干燥过程中玉米籽粒内部水分的扩散过程,优化干燥工艺参数,本文采用模拟研究和实验研究方法分析干燥过程中玉米籽粒内部水分分布随时间的变化规律。玉米籽粒由种皮、角质胚乳、粉质胚乳和胚四组分组成,四种组分水分扩散系数各不相同,本文分别假设玉米籽粒由单组分均质体和多组分非均质体组成,分别建立了玉米籽粒的干燥数学模型,利用COMSOL Multiphysics模块模拟研究了玉米籽粒内部的水分变化情况,并通过玉米籽粒的薄层干燥实验进行了实验验证。研究结果表明,建立的两个模型均可有效模拟玉米籽粒薄层干燥过程;80℃的模拟值与实验值的差异较70℃的小;玉米籽粒多组分模型精度优于单组分模型精度。
To study the moisture diffusion of a single corn kernel during drying, and to optimize the drying parameters, the moisture content distribution in the corn kernel over time was researched by the methods of simulation and experimental analysis. Corn kernel consists of four components of seed coat, horny endosperm, farinaceous endosperm and embryo, all of whose diffusion coefficient differ. Then two hypotheses are proposed: one is that the corn kernel consists of isotrot)ic monoeomponent: the other is that the corn kernel consists of multicomponent described above. Based on the hypotheses, different drying mathematical models of a singh' corn kernel were built, and solved by the software of COMSOL Multiphysies for mass transfer. Thin layer drying experiment of the corn kernel was conducted to validate the models. The simulation and experimental results indicated that both of the models could explain the drying process of corn ke.rnel well. The difference between simulation and experimental results under 80℃ is smaller than that of 70℃. And the simulation precision of multieomponent model is better than that of monoeomponent model.