Theoretical study of heat transport in thermoacoustic stacks having arbitrary plate separation.

Abstract

Thermoacoustic heat engines can be simply described as devices where heat transport is caused by the interaction between a standing wave and a stationary, parallel plate structure called the stack. Simplified calculations of this heat transport have been discussed previously, which assume perfect standing waves (infinite standing wave ratio) and plate separations that are large relative to a thermal penetration depth. A theory will be presented that is generalized to describe systems with arbitrary plate separation and SWR. Using this theory, the spectrum of heat engine designs that span ‘‘classic’’ thermoacoustic engines on the one extreme, and Stirling cycle engines on the other extreme, can be compared. Some results are that Stirling cycle engines can be more efficient than standard thermoacoustic engines and that, given some practical constraints, thermoacoustic engines can deliver more power than a comparable Stirling engine. Other results may help to design an improved engine that combines the characteristics of both thermoacoustic and Stirling engines. [Work supported by ONR and NRL.]