LTD Stirling engine with regenerator. Numerical and experimental study

In this paper, a model of a low temperature difference (LTD) Stirling engine with regenerator is presented. The equations governing the heat transfer and the compressible fluid dynamics are solved numerically as a coupled system, including the ideal gas state equation, Navier Stokes equations and energy balance. The engine cycle induces flow compression, expansion and regeneration in free volumes and through porous media. The present developed CFD model makes possible to obtain the instantaneous values of the physical parameters (pressure, temperature, velocity, density, etc.). With these obtained values, the continuous p-V cycle can be analysed which leads to the mechanical work calculation. The results of the simulation concerning an engine with regeneration is compared to those obtained in previous work by an engine without regeneration and validated with experimental data obtained under similar conditions without regeneration. The preliminary results show the important improvement due to the engine regeneration operation and the related regenerator porosity effect allowing the reduction of the pressure drop and viscous dissipation.