Multiphysics coupled simulation to study the mechanism of convection in microwave heating

Abstract:

When a microwave oven heats liquid foods such as water or milk, there is a phenomenon of longitudinal and transverse temperature inhomogeneity because of the nonuniform of electromagnetic field distribution. To explore the mechanism for the phenomenon, the multiphysics simulation software was used to simulate the temperature change when heating a cup of water from bottom by microwave and conventional electric heaters. By analyzing the effect of the convection on the distribution of electric field and temperature, it came to conclusion that convection only occurs in the local area owing to nonuniform of microwave heating, different from the traditional method where it forms a bottomup onvection, which eventually leads to the temperature delamination.