Study on a thermoacoustic cooling system to drive the fundamental resonance frequency by connecting a triggered tube

Abstract

A thermoacoustic cooling system to drive a looped-tube with the fundamental resonance frequency by connecting a triggered tube is proposed. The heat pump is located in the triggered-tube. The existence of dc flows, which is caused by harmonics in the looped tube, has been pointed out as negative effects. The presented thermoacoustic cooling system, however, connected the triggered-tube is expected to suppress the harmonics and to improve cooling effect, so that the length of the triggered tube is designed to have the fundamental resonance frequency. It is well known that the phase relation between sound pressure and particle velocity is important, and approximately in-phase relation is the best position for cooling effect. In the presented system, the sound energy is supplied from the looped tube. It is important to know the best connecting position where the phase relation is approximately in phase. The sound pressures were observed, then the phase relations were calculated by two-sensor power method. By using results, the best position of the triggered tube was decided. It is confirmed that the presented system can realize the suppression of harmonics and the decrease of outlet temperature. It is also confirmed that the decrease of temperature has the higher effects compared with the looped tube in the same environmental conditions.