The measurements of thermoacoustic phenomena using thermoacoustic couples

Abstract

Thermoacoustic heat transport and its applications, such as thermoacoustic engines and refrigerators, have been discussed in a number of articles over the past several years. However, lacking from these articles is a thorough, quantitative experimental investigation of the basic theory underlying thermoacoustic heat transport. Such an investigation is the purpose of this thesis. A logical starting point for such a study is to investigate the simplest class of thermoacoustic engine - a stack of short plates referred to as a ThermoAcoustic Couple, or TAC. The utility of this choice is that the theory can be reduced to its simplest form for analysis of the results. The results of measurements of thermoacoustically generated temperature gradients in TACs subjected to acoustic standing waves are reported. The value of the temperature gradient, which results from an acoustically generated entropy flow in the gas in thermal contact with the plate, is a function of the acoustic pressure amplitude, the mean gas pressure, the Prandtl number of the gas, the configuration of the TAC, and its position in the standing wave.