Multi-physics Study Of High Efficiency,high Uniformity And Miniaturization Coaxial Microwave Heater

Microwave heating has excellent characteristics such as non-contact heating and fast heating speed.In this thesis,on the principle of the quarter-wavelength coaxial resonant cavity,an improved structural research design is carried out to enhance the heating efficiency and uniformity of the cavity,which is applied to the field of Chinese medicine moxibustion.The use of microwave uniform heating of moxa columns is expected to retain the medicinal effect of mugwort while reducing the harm caused by moxa smoke and realizing smoke-free moxibustion.The main work includes:1.Based on the principle of the quarter-wavelength coaxial resonant cavity,three improved cavity structures,including central probe cavity,contact four-probe cavity,and non-contact four-probe cavity,are proposed for enhancing the heating up speed and uniformity of coaxial resonant cavity.The HFSS simulation software is used to optimize the three cavity structures respectively,focusing on the improvement of electric field uniformity.2.The electromagnetic-thermal multi-physical field simulation analysis of the heating cavity with optimized electromagnetic field design was performed using HFSS and ANSYS software to predict the temperature distribution of the heating medium-moxa column.The temperature uniformity was characterized using the custom temperature coefficient of variation COV,and the COVs of the three cavities were obtained as 0.53,0.51,and 0.349 after a heating time of 60 s with a 10 W microwave feed,respectively.3.The three cavities were mechanically machined,assembled,and tested for basic performance,and the test results showed that the machined cavities met the standards.And a small low-power microwave heating experimental platform was built using a variable frequency solid-state microwave source,and microwave heating experiments were conducted on the moxa pillars,and the experimental results showed that the cavities were able to sustain high-efficiency feed-throughs during the heating process.The temperature of the heated moxa column surface was measured using a handheld thermal imager,and the simulation and design were initially validated by comparing the actual measurement data with the simulation data.