A Simple Model of Stirling Machine (Engine) with Free Working Piston

Regenerator in the Stirling engine is the most important element; the equation of momentum conservation has been proposed for the mass of gas in it. This makes it possible to take into account relaxation hydrodynamic processes in the regenerator and, as a consequence, the model is simplified greatly. The simulation was carried out in the isothermal approximation. In the engine, at the initial stage, high-frequency (~10² Hz or more) and low-frequency oscillations (~10 Hz or less) originate. The movement of the working piston and displacer corresponds to low frequency vibrations. Without relaxation processes in the regenerator, the Stirling engine does not work. There is a minimum temperature difference between the heater and cooler, below which a free-piston engine also does not operate, but can operate like another type of Stirling engine.