电动声源热声致冷机声学和计算实例

我们将各种热声致机简化为一包括声学终端在内的声管道系统，并通过实例讨论了致冷机的声学特性，该管道系统与一般声管道不同：１．在热声堆中热波和粘滞波不可不计。２．在热声堆与声管连接时，必需考虑合成波的体积流；而热声堆内只需考虑传播波的体积流。本文对此提出了阻抗连接条件的修正。实例使用电动扬声器为声源，给出了热声行波和驻波致冷的声学计算方法以及它们的声学特性，所用扬声器的标称伏安为１００ＶＡ，可为热声致

Acoustics and Illustration For Thermoacoustic Refrigerators With Electrodynamic Sound Source

In this paper, we simulate tbermoacoustic refrigerators as an acoustic pipe system with a specified acoustic terminal and discusse the pipe system by an example. This pipe system is different from a common acoustic pipe system because the thermal wave and viscous wave in a thermoacoustic stack must be taken into account in addition to the propagating wave. This is very important in the consi deration of the connection condition of the stack and a pipe section because at the joint the volume velocity at the end of the stack is the volume velocity of the re sultant wave, the sum of the propagating wave and the thermal and viscous waves. But in the stack only the propagating wave mode is needed- We have worked out the connection condition of impedance at the joint. In the example, we used an electrodynamic loudspeaker as the sound source of the refrigerator and demons trated a method of calculation. Results show the acoustic requirements and the con ditions for two ideal thermoacoustic refrigerators: the thermoacoustic progressive wave and standing wave refrigerators. The nominaI electric load of the loudspeaker is 100 VA. It can produce about 30 W acoustic power to the thermoacoustic refrig erators. The acoustic power input to the thermoacoustic refrigerator is depend ent on the distance from the loudspeaker to the thermoacoustic stack. The favourable dist ance is about 1/4 wavelength for the progressive wave refrigerator and as short as possible for the standing wave one.