Numerical study on regenerative effectiveness of parallel-plate regenerator for Stirling engine

Abstract

ABSTRACT Due to the excellent heat transfer performance and low pressure drop, the parallel-plate regenerator (PPR) is very suitable for use in Stirling engines. At present, researches on the application of PPR in Stirling engines are rare. The axial heat conduction loss in PPR is a key factor that affects the heat transfer performance. Therefore, in this paper, the theoretical model of PPR operated under the Stirling engine working conditions is studied numerically, the regenerative effectiveness is taken as the target parameter, and the influence of axial heat conduction and other important parameters are explored. The results show that the axial heat conduction is detrimental to regenerative effectiveness, the regenerative effectiveness does not vary monotonically with the increase in the thermal conductivity, the copper regenerator with higher thermal conductivity has a lower regenerative effectiveness because of its higher axial thermal conductivity. The working frequency and the thermal properties of the working fluids have a comprehensive effect on the regenerative effectiveness, for high thermal diffusivity working fluids, such as helium and hydrogen, the regenerative effectiveness is high, while for low thermal diffusivity working fluid, such as carbon dioxide, the regenerative effectiveness is relatively low, and does not vary monotonously with frequency. The regenerative effectiveness increases with the reduction of the plate spacing, the plate spacing should be determined by considering the regenerative effectiveness and the pressure drop comprehensively. It is recommended that the stainless steel be a suitable material for the plates, and helium be the suitable working fluid.