Acoustical power amplification and damping by temperature gradients

J Acoust Soc Am. 2011 Jan;129(1):132-7. doi: 10.1121/1.3518776.

Abstract

Ceperley proposed a concept of a traveling wave heat engine ["A pistonless Stirling engine-The traveling wave heat engine," J. Acoust. Soc. Am. 66, 1508-1513 (1979).] that provided a starting point of thermoacoustics today. This paper verifies experimentally his idea through observation of amplification and strong damping of a plane acoustic traveling wave as it passes through axial temperature gradients. The acoustic power gain is shown to obey a universal curve specified by a dimensionless parameter ωτα; ω is the angular frequency and τα is the relaxation time for the gas to thermally equilibrate with channel walls. As an application of his idea, a three-stage acoustic power amplifier is developed, which attains the gain up to 10 with a moderate temperature ratio of 2.3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustics* / instrumentation
  • Amplifiers, Electronic
  • Equipment Design
  • Gases
  • Models, Theoretical
  • Motion
  • Pressure
  • Reproducibility of Results
  • Sound*
  • Temperature*
  • Thermal Conductivity
  • Thermodynamics*
  • Transducers, Pressure

Substances

  • Gases