Coupled thermodynamic–dynamic semi-analytical model of free piston Stirling engines

The study of free piston Stirling engine (FPSE) requires both accurate thermodynamic and dynamic modelling to predict its performances. The steady state behaviour of the engine partly relies on non linear dissipative phenomena such as pressure drop loss within heat exchangers which is dependant on the temperature within the associated components. An analytical thermodynamic model which encompasses the effectiveness and the flaws of the heat exchangers and the regenerator has been previously developed and validated. A semi-analytical dynamic model of FPSE is developed and presented in this paper. The thermodynamic model is used to define the thermal variables that are used in the dynamic model which evaluates the kinematic results. Thus, a coupled iterative strategy has been used to perform a global simulation. The global modelling approach has been validated using the experimental data available from the NASA RE-1000 Stirling engine prototype. The resulting coupled thermodynamic–dynamic model using a standardized description of the engine allows efficient and realistic preliminary design of FPSE.

Research highlights
► The free piston Stirling behaviour relies on its thermal and dynamic features.
► A global semi-analytical model for preliminary design is developed.
► The model compared with NASA-RE1000 experimental data shows good correlations.