Study on energy conversion characteristics of a high frequency standing-wave thermoacoustic heat engine

A thermoacoustic heat engine (TAHE) is one kind of new power system which can simply convert heat into mechanical power in forms of acoustic wave without any moving mechanical components. This article focuses on using variable acoustical load method to study the energy conversion characteristics of a high frequency standing wave TAHE whose working frequency is around 300 Hz. The coupling relationship between the TAHE and the load is firstly investigated numerically and shows that the output of the TAHE reaches the maximum when the amplitudes of the acoustic resistance and compliance impedance of the load equal. Then, the influence of key parameters of the TAHE, such as the heating power, mean pressure, the dimensions of the stack and resonator on the acoustic power output is analyzed. It indicates that the thermal efficiency of the TAHE could be improved by increasing the mean pressure and the stack length, and by using the tapered resonator. The theoretical analysis and experimental results reported in this work may provide a good reference for building an efficient standing-wave thermoacoustic heat engine with high frequency operation.