Theoretical investigation of temperature distribution uniformity in wood during microwave drying in three-port feeding circular resonant cavity

The temperature distribution within wood samples during microwave drying is significantly influenced by the dimensions of the wood sample, microwave frequency, heating time, and moisture content of the wood. Here, the temperature distribution inside the wood during microwave drying has been studied by finite element analysis in a three-port feeding circular resonant cavity. With an increasing radius of the wood, the calculated temperature variation coefficient decreased from 54.3 to 23.5% and the energy efficiency increased from 18 to 95%. When the radius of the wood was 0.8 times that of the circular cavity, the drying process was optimal. The theoretical calculations indicated that the length of the wood also affects the temperature variation coefficient. When the length of wood was more than the height of waveguide, the temperature variation coefficient was less than 40.5% and the energy efficiency was more than 90%. Other factors such as microwave frequency, heating time, and moisture content also influenced the uniformity of temperature distribution. This study helps to better understand the microwave drying process to facilitate its further applications for wood drying.