微波对流联合干燥特性的数值模拟

Numerical Simulation on Drying Characteristics of a Combined Microwave-convection Process

微波对流不仅干燥速度快,而且具有杀菌的特点。文中对微波对流联合干燥过程进行了理论研究。通过对微波对流联合干燥工作机理的定性分析,建立起相应的数学模型和微分控制方程组,并在此基础上对球形物料的微波对流联合干燥特性进行了数值模拟。着重考察了沿半径方向上物料含湿量、水蒸汽压力、温度等随干燥时间的变化关系,计算结果符合理论分析情况,与实验结果也吻合良好。同时发现微波输入功率对内部湿份的迁移、干燥过程的温度变化都有很大的影响。

Combined microwave-convection drying characteristics are investigated by numerical simulation. Combined microwave-convection drying has advantage of swift drying and sterilization. Based on qualitative analyses on the mechanism of combined microwave-convection drying, the differential equations are established and the numerical simulation method is described. The humidity, vapor pressure and temperature, along the radius in a spherical pill, are calculated by the numerical simulation during drying process. The calculation results show the relationship between humidity, vapor pressure, temperature and drying time, and that drying process is greatly influenced by input microwave power. The calculation results are good consistent with the experimental datum.