Simulation of thermoacoustic heat pump effects driven by acoustic radiation in a cavity flow

Computations of coupled phenomena between the fluid and acoustic interactions in the cavity flow and heat conduction in the flat plates (stack) installed in the cavity were performed to investigate the flow conditions for an effective thermoacoustic heat pump driven by acoustic radiation in cavity flows. This research presents the first computational approach for an aeroacoustically excited thermoacoustic heat pump. The effects of the freestream Mach number on the thermoacoustic heat pump were investigated by conducting computations with Mach numbers 0.087 and 0.26, where intense self-sustained oscillations occurred. Sound pressure levels of the cavity tone and power of the related velocity fluctuations in the shear layer were reduced by the installation of the stack compared with the cavity flow without a stack, particularly at a lower Mach number. A steeper temperature gradient along the stack was acquired at a higher Mach number, and thermoacoustic heat pump effects were confirmed in the predicted acoustic oscillatory flow between the stack plates. The computational results present that the interaction between the recirculation flows in the cavity and the stack cause the heating of the flow around the cold top end of the stack. The thermoacoustic heat pump effects are reduced due to the interaction. The present computational method is expected to be useful for investigating the utilization of aerodynamical sound energy through conversion to heat energy. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This research investigated the flow conditions for an effective thermoacoustic heat pump driven by acoustic radiation in cavity flows. Computational simulations were conducted to analyze the coupled phenomena between fluid and acoustic interactions as well as heat conduction in the flat plates installed in the cavity. The results showed that the installation of the stack reduced sound pressure levels and power of velocity fluctuations compared to the cavity flow without a stack. The computational method used in this study is expected to be valuable for exploring the utilization of aerodynamical sound energy for heat energy conversion.