Investigation on hydrodynamic characteristics of a Stirling regenerator matrix using porous media approach: a CFD study

Abstract

In this study, hydrodynamic characteristics of a Stirling regenerator matrix are predicted by porous medium based modeling. A regenerator is designed to be used in the beta type Stirling engine. CFD analysis of the designed regenerator is performed by the ANSYS Fluent software with porous media model. The flow properties in porous media are generally approximated by Forchheimer or Ergun flow regime. The equation of the Forchheimer flow model consists of two-term: viscous loss and the inertial loss. The viscous resistance and inertial resistance factors of the porous medium to be used in CFD analysis is determined from published experimental results for a regenerator made by stainless steel with the porosity of 70 %. The CFD simulation are validated by comparing the calculated the velocity distributions at the exit of the regenerator with results of previously published paper. By using both resistance factors, pressure drops, and friction factors of the regenerator matrix are calculated via CFD analysis. The friction results are interpolated to generate a correlation equation that can be able to calculate the pressure drops in the flow direction of the regenerator and to use in future numerical simulations.