| Due to the industrial technology and the rapid development of modern science and technology,people for cryogenic refrigerator performance requirements are also constantly improving,set economy,environmental protection,efficient as one of the refrigeration technology is our urgent need.The thermoacoustic refrigerator is developed to adapt to the era development in line with international advocate the concept of green environmental protection refrigeration device,it has the advantages that the traditional refrigeration equipment does not have,such as green environmental protection,long service life,high system stability and simple structure.According to thermoacoustic theory,in order to realize miniaturization and high efficiency of thermoacoustic refrigerator,it is necessary to find the optimal frequency matching condition between acoustic drive and refrigerator,so as to obtain the ideal sound field conducive to thermoacoustic effect.In view of this problem,this paper mainly starts from the ideal sound field which can improve the refrigeration efficiency.Based on the basic theory of thermoacoustic,the following research work is carried out on the whole thermoacoustic refrigeration system by means of numerical simulation and experiment:(1)Based on the thermoacoustic effect theory,the factors affecting the refrigeration effect of standing wave thermoacoustic refrigerator are analyzed theoretically.And the acoustic software ATILA is used to simulate the acoustic field in the refrigerator resonator,and the optimal harmonic response frequency is found,so as to obtain a better standing wave acoustic field,which provides a theoretical basis for subsequent experiments.(2)By means of experiment,the amplitude of sound pressure in the resonant cavity of refrigerator under different excitation frequencies and its influence on the refrigeration effect are studied.The results show that when the excitation frequency is within the cutoff frequency range,the larger the sound pressure value generated in the acoustic field,the greater the temperature difference between the two ends of the stack,and the more obvious the thermoacoustic effect.(3)The traveling standing wave thermoacoustic refrigerator was analyzed.In order to study the internal sound pressure distribution rule,the traveling standing wave thermoacoustic refrigerator was simplified into a two-dimensional p-tube model for sound field simulation analysis and experimental research in the acoustic software ATILA.The results show that the amplification of the amplitude of sound pressure in the p-type tube is different at different frequencies,and the phenomenon of standing wave exists in the p-type tube instead of traveling wave.However,compared with standing wave refrigerator,non-piston mode appears earlier in the resonator cavity,which reduces the frequency range of thermoacoustic effect.(4)Three different cross-section designs were carried out for the annular loop part of p-type tube,and the acoustic field analysis was carried out by importing the acoustic software ATILA.It was found that the sound pressure amplitude amplification effect of the annular loop with right-angled edges was different from that of the annular loop without right-angled edges due to the dispersion phenomenon of the annular loop with right-angled edges compared with that without right-angled edges.(5)In this paper,based on the near-field characteristics of the vibration of the piston plate in the ultra-high frequency range,the distribution of the sound pressure in the resonant cavity of the radiation plate in the near-field vibration of the ultrasonic miniature thermoacoustic refrigerator is theoretically analyzed.The finite element analysis software ATILA was used to simulate the acoustic field distribution in the cavity.From the theory and simulation,it can be seen that in the ultra-high frequency range,the sound pressure amplitude in the near-field of the vibration of the radiant panel piston appears "bright zone" and "dark zone" Chiller has important research significance. |
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