Investigation of a toroidal thermoacoustic prime mover Free

A typical thermoacoustic prime mover has a well‐defined acoustic impedance in at least one place. For instance, many prime movers have a rigid end which forces the acoustic velocity to be zero at that point. Such ‘‘built‐in’’ boundary conditions serve as convenient starting points for computational analysis of the performance of a device. They also serve to place the stack in a thermoacoustically effective position relative to the acoustic field. A toroidal prime mover poses some interesting questions. A toroidal prime mover has the cold end connected to the hot end via a duct that does not impose any obvious dominating boundary conditions that would force a node or antinode at any particular point. Indeed, if the stack and heat exchangers were not there and the toroid had a uniform cross section, a standing wave would have no preferential orientation. In this work, a toroidal thermoacoustic prime mover has been built and an experimental study is presented. A model based on acoustic propagation in infinite periodic waveguides is proposed to simulate the experimental results. [Work supported by the Office of Naval Research.]