Chapter 80 - Study on thermoacoustic resonance pipe driven by loudspeaker using two-microphone method

Abstract

This chapter covers an experiment in which a system is set up to measure the acoustic properties in the thermoacoustic resonance pipe using the two-microphone method. Then the distributions of the sound pressure, particle velocity, and acoustic impedance in the pipe are calculated utilizing the decomposition theory. On the other hand, the acoustic impedance of the loudspeaker is measured using the clio software. Therefore the match frequency between the loudspeaker and resonance pipe can be found, which is just the optimized working frequency of the system. It is shown that the most efficient working frequency of a thermoacoustic refrigerator driven by a loudspeaker is not the resonance frequency of the pipe itself. The two-microphone method is used to measure the match frequency of a thermoacoustic system and the sound pressure and particle velocity distributions in the pipe. The results demonstrate that the two-microphone method is appropriate to study the characteristics of a thermoacoustic pipe. By this method the optimized working frequency and the proper position of the stack of a thermoacoustic system can be obtained easily.