Computation of Nonlinear and Edge Effects in a Thermoacoustic Refrigerator

In thermoacoustic refrigerators, the acoustic energy provided by an acoustic source is used to pump heat from a cold reservoir. Such refrigerators work with benign fluids, and may possibly be miniaturized, offering an application to microelectronic refrigeration. The linear theory frequently used to predict thermoacoustic refrigerators performance, because it relies on the simplification of the governing equations, can not account for all the phenomena involved in thermoacoustic heat pumping. In the present work, the full compressible two-dimensional Navier-Stokes equations are solved numerically, and the flow and heat transfer above a plate immerged in an acoustic standing wave are computed. Some phenomena, which are not taken into account in the linear theory, are observed. Non-harmonic temperature variations are found and are explained using the results of a former nonlinear analysis. The effect of vortical motions at the extremity of the stack plates on heat transfer is studied.