Heat Transfer with Phase Change Problems Using microwave heating

微波加热正在成为最有趣的加热材料的方法之一。特别是对液固相混合物使用微波，微波的大部分被液相部分吸收，加热的选择性更强。本文对微波加热引起的冰的融化和非饱和填料床的干燥进行了实验和理论研究。所得结果总结如下。1)在微波加热融化冰与水组成的层时，水与冰之间介电性质的差异对入射微波的熔化方向有很大的影响。基于一维模型分析了微波加热下冰的融化过程。(2)对于层状充填层的熔化，发生内部熔化。发现熔化过程与入射微波强度、介电常数和层的初始温度有关。3)微波加热干燥非饱和填料床时，干燥层内温度随着干燥的进行而下降，颗粒直径越小，毛细力越大，干燥时间越短。

Microwave heating is becoming one of the most interesting methods for heating materials. In particular, using microwave for the mixture of liquid and solid phases, major part of microwave is absorbed to the part of liquid phase and the heating is more selective.In this study, the melting of ice and the drying of unsaturated packed beds due to microwave heating have been investigated experimentally and theoretically. The results to obtained are summarized as follows.1) In the melting of layrs composed of ice and water by microwave heating, the direction of melting against the incident microwave strongly depends on the difference in the dielectric properties between water and ice. The melting of ice by microwave heating was analyzed based on the one dimensional model.2) For the melting of layred packed beds, the internal melting occurred. The melting process was found to depend on the intensity of incident microwave, dielectric constant and initial temperature of the layr.3) In the drying of unsaturated packed beds by microwave heating, the temperature in a dry layr drops as drying proceeds and a smaller diameter of particles results in a faster drying time because of having a higher capillary force.