温度梯度引起的声学功率放大和阻尼。

Acoustical power amplification and damping by temperature gradients.

机构信息

Department of Mechanical Systems and Design, Tohoku University, Sendai, Miyagi 980-8579, Japan.

出版信息

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.

摘要

塞珀利提出了行波热机的概念["无活塞斯特林发动机——行波热机，" J. 声学学会 66, 1508-1513 (1979)。]，这为今天的热声提供了一个起点。本文通过观察平面声波在穿过轴向温度梯度时的放大和强烈阻尼，实验验证了他的观点。结果表明，声功率增益服从无量纲参数ωτα规定的通用曲线；ω 是角频率，τα 是气体与通道壁热平衡的弛豫时间。作为他的想法的一个应用，开发了一个三级声功率放大器，在 2.3 的适度温度比下获得了高达 10 的增益。