Dynamic-thermodynamic mathematical model of Stirling engine to improve efficiency and power

A dynamic-thermodynamic model of stirling engine is presented to study some of optimization factors on engine thermal efficiency and output power. The optimization factors have been assumed as heater and cooler heat transfer areas, regenerator solid mass amount and its heat transfer area and fluid pressure drop. To study these factors, the model takes into account non-ideal heat transfer, non-uniform pressure distribution and time dependant temperature variation in any stirling engine gas chambers. Calibration parameters also have been defined so that the model should be calibrated via a test result data or simulation data, afterward it can predict the engine behavior while changing the optimization factors.Geometrical dimensions and test results at nominal gas pressure for ST500 stirling engine was used in order to calibrate the model. To ensure the prediction accuracy, comparisons were accomplished between model output and motor test results for different gas pressures. Finally the optimization factors of the model were varied separately, model outputs were compared and the most important factor in improving the thermal efficiency and work output was selected. The determined optimization factor was applied to the engine and the thermal efficiency and output power was measured. The engine test results were compared to the model prediction and to previous engine state.