马铃薯微波干燥动力学建模与仿真

Dynamic modeling and simulation of potato microwave drying

采用自制微波热风耦合干燥系统,对马铃薯丁在不同微波功率(600、900、1 200和1 500 W)干燥下的温度和含水率进行试验,得到马铃薯微波干燥曲线、干燥速率曲线以及干燥的最佳微波功率密度,建立马铃薯丁微波干燥动力学模型和有效水分扩散模型。将马铃薯丁的有效水分扩散系数模型代入到COMSOL Multiphysics软件中,建立电磁场、固体传热和稀物质传递三场耦合模型,结果表明,马铃薯丁的微波干燥速率经过270 s的加速期后,便进入降速期,微波干燥的最佳微波功率密度为6 W/g,其干燥模型可用Page方程描述,马铃薯丁微波干燥有效水分扩散系数为4.35×10–9~9.02×10–9 m2/s。

Microwave self–made hot air coupled drying system was used to test the temperature and moisture content of potatoes under microwave powers of 600,900,1 200 and 1 500 W.The microwave drying curve,drying rate and optimum microwave power density was obtained.The dynamic modeling of potato microwave drying and the effective water diffusion model have also been built.By substituting the effective moisture diffusivity model of potato dices into the COMSOL multiphysics software,the three field coupling model of electromagnetic field,solid heat transfer and dilute material transfer was established.The result showed that the microwave drying rate of potato was in a long period of decline after a brief 270 s acceleration period.The optimum microwave power density of microwave drying was 6 W/g,whose drying model could be described by Page equation.The effective moisture diffusivity of potato dices microwave drying was between 4.35×10–9– 9.02×10–9 m2/s.The dependence of moisture and temperature of potato on microwave power and heating time was simulated during the process of microwave heating,which provide theoretical basis and data support for potato microwave drying process.