一次元シミュレーションによる定在波型熱音響冷凍機の数値解析

抄録

In this paper, a numerical simulation for a standing-wave thermoacoustic refrigerator using the equations of conservation law are proposed. In this simulation, the gas flow in the thermoacoustic refrigerator is expressed by the quasi one-dimensional model to reduce the computational load. Since the equations of conservation law are solved directly in the simulation in contrast to the conventional analysis applying the thermoacoustic theory, our simulation is excellent in adaptability and extensibility and can be used for developing actual machines. The equations of continuity, motion, energy and the state of the gas were solved utilizing a TVD scheme for the spatial difference and Heun’s method for the time difference. The numerical simulations were performed on ten types of thermoacoustic refrigerators having regenerators of different thermophysical properties and hydraulic diameters, and the simulation results were compared with the corresponding experimental results. As for the results, a heat pump effect, or thermoacoustic refrigerating effect, was observed successfully by means of our simulation. The highest thermoacoustic refrigerating effect was obtained when a product ωτ of angular frequency of sound wave ω and thermal relaxation time τ was around 5, and the result agreed well with the previous research. Furthermore, the simulation results of thermoacoustic refrigerating effect for the different types of refrigerators were consistent with experimental results within an error of 10%. These results verify the validity of our proposed simulation method.