Abstract
•Heating rate was measured for the different microwave and mixing conditions.•The heating rate was influenced by both penetration depth and mixing.•The heating homogeneity was effectively described by two dimensionless numbers, As and Re.•The correlation provides an practical method to homogenize temperature in microwave reactor.
The heating rates of the microwave in combination with stirring were obtained for a cylindrical container. The experiment was conducted at different operating parameters such as stirring speed, stirrer length, and the penetration depth of microwave. The heating homogeneity is characterized by a ratio between two heating values calculated from microwave penetration and centre temperature. The ratio was evaluated by two dimensionless numbers, the mixing Reynolds number (Re) and our dimensionless microwave number (As) proposed in a previous study. It was found that the heating ratio is linearly correlated to the simple combination of Re and As. The results provide a simple and practical formula for the optimization of microwave heating in industrial processes.