Abstract:

In conventional heat transfer studies, mostly dealing with steady-state flow phenomena, a well-established database is available in the literature. In thermoacoustics, however, the flow oscillates with a zero mean velocity and heat transfer rates in this physical situation cannot be easily predicted. As it was shown previously [M. Wetzel and C. Herman, J. Acoust. Soc. Am. 100, 2846(A) (1996)], a tool to investigate such high-speed heat transfer phenomena is holographic interferometry combined with high-speed cinematography. Interferometric measurements were conducted for drive ratios from 1% to 3%. Applying digital image processing to the obtained interferometric fringe pattern, the oscillating temperature field was measured and acoustic temperature fluctuations of the order of 1 K could be resolved. From the temperature fields the important heat transfer parameters such as local heat fluxes, heat transfer coefficients, and Nusselt numbers were determined at the edge of two stack plates. [Work supported by the Office of Naval Research.]