Multi-physics Simulation Of Microwave Heating Of Food

Since the first microwave oven was invented in 1947, microwave has experienced for almost decade-long development. The application of microwave evolves from simple heating to steaming, boiling, grilling and fermentation, etc. With the constant expansion of microwave functions, recent years saw the presence of various microwave accessories, e.g., microwave rice steamer, fish steamer, microwave egg steamer, etc., which can satisfy the need for different cooking methods. Thereby microwave oven boasts increasingly mature cooking functions. The accessories of microwave oven steamer book foods with the steams produced by the microwave oven after adding hot water. Its heating methods include microwave heating, steam heating and microwave-steam mixed heating. However, when adopting the microwave heating, foods easily lose moisture, taste worse and become less nutrient. The steam heating is less efficient. For this reason, the paper takes the microwave-steam mixed heating to improve these two defects. Improvements are made on microwave-steam device and optimization design is provided by combining multi-physics simulation. Slot antennas are added to the device, which improves the heating efficiency when the microwave and steam work at the same time.This paper mainly conducts the simulation and experimental study on the microwave-steam heating device, specifically:1. Through simulation and experimental analysis, it overcomes the shortcoming that metal containers are not allowed to put into microwave oven and solves the ignition of the microwave oven’s metal accessory; the paper realizes microwave-steam mixed heating by adding a slot antenna to the metal microwave-steam device. At the same time, optimization is given to the antenna size and heating effect to get the structure of 4-lot and 8-slot-antenna steamer. Finally, the experiment shows the addition of slot antenna improves the heating efficiency by 12.5%.2. Analysis is conducted on the differences of the food steaming effect of two microwave oven rice steaming accessories. The simulation results show that the stainless steel microwave accessory boasts more even heating effects. Furthermore, the paper also studies the impact of steaming accessory and steamers on magnetron and cavity temperature with different loads. Compared with rice steaming accessories, steamers poor match microwave oven. It causes the high temperature of the magnetron’s anode.3. Combined with the simulation results and multi-physics analysis, the paper compares the heating temperature distribution of the microwave-steam device before and after adding the slot antenna. The experimental results show that through adding the slot antenna, in the beginning of heating, microwave plays a dominant role in heating. However, over time, steam heating plays a leading role. Therefore, with the joint work of microwave and steam, the heating effect is improved.