Jay A. Lightfoot
Richard Raspet
Henry E. Bass
Dept. of Phys. and Astron., Univ. of Mississippi, University, MS 38677
W. Patrick Arnott
Univ. of Nevada, Reno, NV 89506
Rott developed the theory of thermally driven acoustic oscillations in tubes with variable cross section. Bennett, in her dissertation, considered plane-wave thermoacoustic refrigerators with variable plate separation and found them to have higher COP's than those with parallel plates. This principle has application to the work in radial wave thermoacoustics, since variable plate separation is a natural product of radial vertical-plate engines with constant plate thickness. Bennett appears to have overlooked a term in the wave equation. An analysis is presented including this term to study two important questions: What is the optimal slope, and even more basic, which side (hot or cold) should have the greater plate separation? [This work was supported by the Office of Naval Research.]