Influence Of Stirrer On Heating Characteristics In High Power Rectangular Microwave Reactor

Microwave heating has the characteristics of inside-out and instantaneous controllable heating,and has been widely used in food cooking,agricultural product drying,microwave metallurgy,uranium ore processing,microwave physiotherapy,tumor treatment and other fields.However,due to similar closed characteristics of most microwave reaction cavities,the microwave field solution in it has intrinsic characteristics.This characteristic leads to uneven distribution of the microwave field,which in turn leads to uneven microwave heating from the heat source.According to the electromagnetic field theory,setting a microwave stirrer in the reaction cavity can disturb the electromagnetic field boundary conditions during the heating process,thereby disturbing the distribution of microwave field.This method makes it possible to improve the heating efficiency and heating uniformity of the microwave reaction chamber.Based on the detailed introduction and analysis of microwave heating theory,resonant cavity theory,waveguide theory,material electromagnetic properties,electromagnetic stirrer and so on,three high-power rectangular microwave reaction cavities with stirrers are designed and their heating characteristics are studied.The main research work is as follows:(1)Based on the detailed introduction and analysis of the theoretical knowledge of microwave heating,three high-power rectangular microwave reaction cavities with linear stirrer,H-shaped stirrer and metamaterial stirrer are designed.The corresponding simulation calculation method is given,and the effectiveness of the method is verified.(2)The heating characteristics of seven self-designed high power rectangular microwave reaction cavities with three types of bottom single-line stirrer,side double-line stirrer,bottom H-type stirrer,side single-sided metamaterial stirrer,bottom single-sided metamaterial stirrer,side double-sided metamaterial stirrer,fivesided metamaterial stirrer were calculated and analyzed.(3)When the heating material is cylindrical or square potato,sweet potato,panax notoginseng powder,fly ash,the influence of parameters such as the width and rotation angle of the linear structure of the stirrer,the width and rotation angle of the H-shaped structure,the thickness of the metamaterial structure and the angle of the rotating sheet on the heating efficiency and uniformity were studied.Finally,the optimal agitator design and operating parameters are given.The development of the above work provides a new way to improve the efficiency and uniformity of microwave heating,provides a reference for the design of a new type of stirrer in microwave reaction cavities,and contributes to the design theory of a new type of microwave reaction cavities.