玉米热风干燥特性模拟研究

Simulation of corn drying characteristics with hot air

针对玉米热风干燥时内部发生的传热传质过程,以单个玉米为研究对象,构建了三维多组分干燥仿真模型。玉米由表皮、硬质胚乳、软质胚乳和胚四部分组成,扩散系数各不相同,以傅里叶导热方程、菲克扩散方程作为控制方程,表面水分蒸发作为边界条件,利用COMSOL Multiphysics模拟研究了整个干燥过程中内部温度场与浓度场的变化情况。研究表明,玉米干燥过程中一直处于降速干燥,外界条件风速、相对湿度对干燥过程中含水率影响不大,表皮层是干燥过程水分迁移主要的传质阻力部分。

To study the internal heat and mass transfer process of a single corn kernel during drying, constructed a three-dimensional multi-component drying simulation model with single corn as the research object. Corn kernel consists of epidermis, hard endosperm, soft endosperm, and embryo, and their diffusion coefficients differ. The Fourier heat conduction equation and Fick’s diffusion equation are used as the governing equation, surface water evaporation is used as the boundary condition, and the software of COMSOL Multiphysics is taken to investigate the variation of the internal temperature field and concentration field during the whole drying process. The results have shown that the drying speed has been slowing down during drying, and external conditions such as wind speed and relative humidity have little effect on the change of water content. The main mass transfer resistance during corn drying comes from the pericarp. It has certain theoretical guiding significance for the simulation study of corn drying.