An investigation of thermo–fluid dynamic performance of a Stirling engine regenerator by means of OpenFOAM

A good design of the regenerator of a Stirling engine is required to obtain high performance and efficiency of such an engine. The regenerator is basically a heat-exchanger placed between the hot and cold working streams. It usually consists of stacked woven wires. The fluid pressure drop and heat transfer are the main parameters of the regenerator influencing the engine performance. In this work, friction coefficient, thermal efficiency and Nusselt number are numerically evaluated in order to assess the performance of the regenerator. The open-source software OpenFOAM is used to analyse the thermo-fluid dynamic behaviour of a regenerator wire netting at different Reynolds numbers. Firstly, isothermal air flows and adiabatic wire matrices are considered, by assuming the fluid flowing through the regenerator as incompressible. Then, air flows with a fluid temperature of 500 K and wires at a temperature of 300 K are analysed. The results are compared with those obtained by means of the commercial software Ansys Fluent.