Effect of Load Size on Power Absorbed During Microwave Heating in a Cavity: Electromagnetic Modeling and Experimental Validation

Abstract

The effect of material size on the amount and uniformity of power absorbed during microwave heating was evaluated by numerical and experimental methods. A three-dimensional (3D) mathematical model, based on the Maxwell's equations of electromagnetism, was solved using the Finite Element Method to predict the power dissipated in the sample. Experimental analysis was performed using a domestic oven and distilled water. Experimental and numerical results showed a good agreement to each other. However, a complex relationship exists between sample size and absorbed power. The modification of the resonance modes in the oven when the sample size is changed may explain it. Furthermore, heating uniformity decreases as the water load size increases because microwave power dissipation occurs mostly near the sample surface due to a lower intensity of resonances inside large samples.