A study on the effect of metal skeleton auxiliary heating device on microwave heating efficiency of batch Al2O3 ceramics

•Based on the reflection effect of metal materials to electromagnetic wave and the theory of generalized transmission line, the distribution of standing wave field in microwave resonant cavity and the relationship between the distribution of standing wave node and anti-node of electromagnetic field were deduced.•Compared with using the SiC auxiliary heating device, the heating efficiency of batch Al2O3 ceramic blocks was improved by 26.4% when the metal skeleton auxiliary heating device was used.•The temperature uniformity of batch Al2O3 ceramic blocks with the metal skeleton auxiliary heating device was 12.5% higher than that of the SiC auxiliary heating device under the same heating time. In order to improve the microwave heating efficiency of the batch Al2O3 ceramics, according to generalized transmission line theory in this paper, the relationship between the amplitude and phase of the electromagnetic field in the microwave resonant cavity was deduced by using the distribution relationship of voltage and current on the transmission line. SiC auxiliary heating plate was used as the auxiliary heating device. Based on the reflection principle of metal material to electromagnetic wave, the metal skeleton was added to SiC auxiliary heating plate. The COMSOL multi-physics field simulation software was used for simulation. The results showed that the addition of metal materials could change the intensity and distribution of the electromagnetic field on SiC auxiliary heating plate and Al2O3 ceramic blocks, so as to affect the microwave energy utilization rate of heating area and the heating efficiency of Al2O3 ceramic blocks. The numerical simulation results showed that the microwave energy utilization rate of the heating area could be improved by adding the metal skeleton in the SiC auxiliary heating plate and employing a reasonable design, so as to improve the overall heating efficiency of the Al2O3 ceramic blocks. Compared with the traditional SiC auxiliary heating device, the heating efficiency of Al2O3 ceramic blocks was improved by 26.4%, and the overall temperature uniformity was improved by 12.5%.