Numerical analysis of transport phenomena in a stirling regenerator

Abstract EN

In the context of increasing the efficiency of alternative energy sources applications, Stirling engines attracted researchers to study the performance since it is an external heat addition engine that can work with renewable heat resources or with waste heat from plants working with fossil fuels with an efficiency equivalent to Carnot efficiency.

Additional advantages exist, such as quiet operation and lower emissions than internal combustion engines.

The regenerator is an essential part of Stirling engine as it plays a vital role in its operation especially in the two isochoric heat transfer processes representing a heat barrier and transferring heat to the fluid in the first half of the cycle and transferring heat from the fluid in the second half of the cycle.

In the last two decades, the development of CFD methods made it possible to study transport phenomena without the need for costly experimental methods and can give more detailed information about the effects of geometrical parameters than the theoretical or analytical methods.

The purpose of this study is to develop a model for an alpha type Stirling engine and using the advantage of geometrical representation in CFD models to study the effect of changing regenerator geometry on engine performance.

Validation of the model against results in the literature was performed.

Results showed that the dimensionless work parameter was 0.011 for the novel geometry while it was 0.065 for the original regenerator, decreasing the engine speed increased the dimensionless work parameter to 0.018, effects of changing apex angle and wall thickness on the dimensionless parameter were investigated.