Research On Heating Efficiency And Uniformity Of Adjustable Cavity Microwave Heater

Requirements for energy saving and emission reduction and green regeneration and so on have promoted the development of electric energy utilization equipment.Microwave heating can directly apply the energy of the microwave field to the heated object,which has many advantages,such as fast speed,strong controllability,and high heating efficiency and it has been widely used in many fields,such as metallurgy,agricultural product drying,chemical engineering,and special material preparation.Microwave reaction chamber is the key equipment for microwave heating.Different microwave reaction chambers will cause different heating efficiency and uniformity.A properly designed microwave reaction chamber can greatly improve the efficiency and uniformity of microwave heating.Based on the analysis of the related theory of microwave reaction cavity,this paper designs a cross-shaped adjustable cavity microwave reaction cavity.The high-frequency electromagnetic field simulation software High Frequency Structure Simulator(HFSS)is used to study the relationship between the feed port and the adjustable cavity wall.The effect of heating efficiency and uniformity has been optimized.Main tasks as follows:(1)Comprehensively analyze the related principles and characteristics of electromagnetic field theory,microwave transmission and resonance theory,microwave reaction cavity components,and microwave heating.Based on the analysis of microwave reaction cavity design theory,initially designed a microwave reaction cavity whose cross-shaped cavity wall was adjustable;(2)The process of modeling the microwave reaction cavity using HFSS is described in detail.The length of the microwave heater inlet,the location of the inlet,the single cavity wall,and the two cavity walls(including the opposite and adjacent surfaces),the influence of design parameters such as four cavity walls on the heating efficiency of microwave heaters are studied using HFSS.The results show that: when the length of the inlet is over 60 mm,the microwave reflection power is small;the heating efficiency decreases as the distance from the center of the inlet increases;when only one cavity wall is adjusted outward,the microwave heating efficiency gradually increases;the effect of adjusting multiple cavity walls on heating efficiency is big,but it can always be maintained above 90%;(3)Based on the detailed introduction of the microwave field sampling method and the uniformity evaluation method,the influence of the number of feed ports and the adjustable cavity wall on the microwave field distribution in the microwave reaction cavity was studied using HFSS.The result of the research shows that simply increasing the number of feed ports cannot improve the uniformity of microwave heating,while adjusting the cavity wall during heating can significantly improve the uniformity of microwave heating.