Numerical simulation and parameter optimization of thermo-acoustic refrigerator driven at large amplitude

Abstract

Two-dimensional numerical simulation of thermo-acoustic refrigerator driven at large amplitude is carried out in this paper. Computation of the parameters is based on a pressure-correction algorithm for compressible flows, removing the limitations of traditional simplified linear model of the thermo-acoustic systems. Firstly, the numerical algorithm is applied to an acoustic resonance chamber. The numerical results are found to be in good agreement with those reported in the literature. We explore the growth of pressure amplitude for harmonic waves of various orders according to the growth of driving amplitude, and show the non-linear phenomena in the refrigerator. Then the parameters affecting the refrigerating performance (including fixing position of the thermo-acoustic stacks, length of the stacks and the heat exchanger, thickness of parallel plates, and the spacing), are investigated in detail, which shows that the performance of thermo-acoustic refrigerators is best when the normalized plate thickness ranges from 0.28 to 0.33, the normalized spacing between plates ranges from 1.37 to 1.51, and the length of heat exchanger is about the peak-to-peak displacement amplitude of the gas in it. Finally these optimized parameters are verified under different charging pressures, driving amplitudes, and working gases, providing references for optimal design of thermo-acoustic refrigerator driven at large amplitude.