Miniature acoustic prime mover operating at 10 kHz

Abstract

A miniature thermoacoustic prime mover was developed for interfacing with electronics and microcircuits where it will be used for thermal management. It operates at approximately 10 kHz; heat is injected to the hot part of the device, the cold part is thermally anchored at room temperature. It consists of a quarter wave resonator of cylindrical geometry, 9 mm long. It has a stack of random porous material between two heat exchangers and it operates with air at one atmosphere. Preliminary results show that this oscillator produces a sound intensity at 110 dB, 1 m away from the open end of the resonator. This level can be raised substantially by careful alignment of the hot and cold parts of the resonator, and by reducing the heat losses along the stack and supporting structure between the hot and cold side of the stack. Based on the high operating frequency, a high power density is expected; such device can be used as the basic unit in an array of acoustic prime movers. This work provides a new functional miniature element that can lead the technology toward even smaller devices and well into the ultrasonic range.