In microwave heating applications, the energy is introduced directly into the workload and as a consequence the quality of the process is highly dependent on the uniformity of the electromagnetic field distribution within it. Since the dielectric properties of foods change during the cooking process and the oven cavity has randomly varying sizes (e.g. the presence of top metal side that varies its height to match the food size), the uniformity of the electromagnetic field distribution is a potential problem. Non-uniform heating, dielectric discharges and thermal runaway are the most critical consequences. In order to prevent such undesired effects, an appropriate oven design based on scientific analyses and a smart control system should be devised. Based on fundamental physical lows, we can extract relationships between critical variables, such as the total power absorption as a function of food’s dielectric properties, size and shape, position, magnetron characteristic parameters and oven cavity sizes.
In this paper a 3D FEM analysis of a microwave oven fed by two magnetrons, based on the COMSOL software, is developed. Simulations show how electrical variables (e.g. electromagnetic field, power) change as function of the workload characteristics (e.g. dielectric properties)
