Influence of phase angle and dead volume on gamma-type Stirling engine power using CFD simulation

•CFD model for gamma-type Stirling engine was developed.•Validation against experiments was performed.•Influence of phase angle and dead volume variation on engine performance was investigated.•Phase angle poses positive effect on engine indicated power up to an optimum value.•Dead volume poses negative effects on engine power and an optimum value was proposed.

This work presents the development and validation of computational fluid dynamics (CFD) model of 500 W gamma-type Stirling engine prototype to highlight the effects posed by phase angle and dead volume variations on engine performance. The model is based on a realistic Local Thermal Non-Equilibrium (LTNE) approach for porous domains in the engine (cooler and regenerator). The simulation results showed an acceptable degree of accuracy of 9% and 5%, respectively when comparing with experimental results in predicting the indicated and cooling powers at different heating temperatures. It is found that the maximum indicated power is achieved at a phase angle of 105° rather than at the common phase angle of 90°. The dead volume (connecting pipe) is observed to pose negative effects on engine indicated power and therefore, an optimum value of pipe diameter exists.