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考虑入射波和反射波,建立行波热声系统内管末端阻抗与管口阻抗的理论模型,详细对比管末端封闭和开口对压力、体积流率、阻抗和声功的影响,指出开口式行波系统的声场特点.在此基础上,研制了一台开口式低频行波热声发生器,它由环形圈、开口式谐振管、回热器和冷热端换热器等元件组成.以1bar空气为工质,运行频率74Hz,在输入热量210W时,管口处声压级达到133.4dB,距离管口0.5m处声压级为101dB,性能已达到低频声源可应用的范围.随着研究的深入,出口处声压级可达到150dB,有望解决现有低频声波发生器声压低、装置复杂、声学性能重复性差等问题,可以为低频远距离噪声实验或者工业声源和振动提供高声强声源.
Considering the incident wave and the reflected wave, a theoretical model of the end-of-pipe impedance and the orifice impedance of the traveling wave thermoacoustic system is established. The effects of the pipe-end seal and the opening on the pressure, volume flow rate, impedance and sound power are compared in detail. Wave system. Based on this, an open-type low-frequency traveling wave thermoacoustic generator was developed, which consists of annular ring, open-ended resonant tube, regenerator and hot and cold side heat exchanger and other components 1bar air as working fluid, the operating frequency of 74Hz, the input heat 210W, the nozzle sound pressure level reached 133.4dB, 0.5m away from the nozzle sound pressure level of 101dB, the performance has reached the range of low-frequency sound source can be applied. With further research, the sound pressure level at the exit can reach 150dB. It is expected to solve the problems of low sound pressure, complicated devices and poor repeatability of acoustic performance of the existing low-frequency sound wave generator, which can provide high-frequency long-distance noise experiment or industrial sound source and vibration Strong sound source.