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针对真空干燥时单体玉米颗粒内部的传热传质过程,开展基于三维实体模型的模拟研究。使用高精度CT扫描玉米颗粒,图像经MIMICS、ANSYS处理,建立实体模型。以傅里叶传热方程、菲克扩散方程作为控制方程,当量辐射传热和表面水分蒸发传质作为边界条件,使用COMSOL软件完成模拟。模拟结果显示干燥过程中颗粒内部为传质控制过程,提高辐射板温度和真空度均能加快干燥,但真空度高于5.5 kPa后效果不明显,玉米初始含水量增大和初始温度降低,会增加总的干燥时间和能耗。
Aiming at the heat and mass transfer process inside single corn particles in vacuum drying, a simulation study based on three-dimensional solid model was carried out. Using high-precision CT scanning of corn particles, the images were processed by MIMICS and ANSYS to establish a solid model. Taking the Fourier heat transfer equation, the Fick diffusion equation as the governing equation, the equivalent radiative heat transfer and the surface moisture evaporation mass transfer as the boundary conditions, the COMSOL software was used to complete the simulation. The simulation results show that the internal particle of the drying process is the mass transfer control process, and the temperature and vacuum degree of the radiation plate can both accelerate the drying. However, the effect is not obvious when the vacuum degree is higher than 5.5 kPa. The initial moisture content and the initial temperature of the corn will increase Total drying time and energy consumption.