A coupled computational model of nonlinear thermoacoustics of standing wave heat engines

Abstract

Thermoacoustic engines have been recently regarded and developed as reliable, long-life, and environment-friendly engines by using experiments or mathematical models. Thermoacoustic mathematical models can be divided into two categories of linear and nonlinear. This paper introduces a coupled 1D-2D computational nonlinear model of heat and flow fields inside loaded standing-wave thermoacoustic engines. On the one hand, the computational cost of the present model is much lower than that of full CFD models whose computational domain contains the entire engine. On the other hand, it does not have the limitation of uniform global cross section as the simplified numerical models do. In addition to the coupled nonlinear model, another simulation based on linear thermoacoustic theory (LTA) has been performed. The model has been well validated using previous experimental data and compared with the results of LTA. Subsequently, the temperature and pressure distributions, the mean acoustic power, and heat transfer and volume flow rate distributions have been presented and discussed. This model is extendable to many other systems whose some parts have negligible multidimensional effects and the other parts have considerable ones.