In this study

the thermoacoustics theory is used to study the output characteristic of a Vuilleumier (VM)-type thermal compressor from the perspective of impedance matching

showing the trend of the output pressure ratio

acoustic power

and efficiency of the thermal compressor on load impedance. The matching relationship between the thermal compressor and load is also analyzed. The program Sage is used to calculate the output characteristics of thermal compressors with two different diameter regenerators. The impedance amplitude for the thermal compressor varies from 4×10-8 to 4×10-9 (Pa?s)/m3 and the phase angle changes between ﹣60° and 60°. The calculation results show that the output pressure ratio

acoustic power

and efficiency for the thermal compressor significantly change with the change in impedance amplitude and phase angle: the impedance amplitude has a significant influence on the output acoustic power when the impedance is capacitive and the influence of the impedance amplitude on the output pressure ratio for the thermal compressor is obvious. Both the impedance amplitude and angle have significant influences on the efficiency. However

the acoustic power

pressure ratio

and efficiency of the thermal compressor cannot simultaneously reach the optimal value at the same impedance. Therefore

it is necessary to comprehensively estimate the acoustic power

pressure ratio

and efficiency of the thermal compressor when matching the design of the low-temperature stage load. From the perspective of the output pressure ratio and acoustic power

the performance of the thermal compressor regenerator with diameter 30 mmis better than that with diameter 40 mm.