A third-order numerical model and transient characterization of a β-type Stirling engine

Abstract Stirling engine is a promising prime mover for distributed energy systems, and a reliable analysis model is essential to design different engines with various applications. In this paper, a third-order model for the Stirling engine is developed, considering the effects of pressure gradient of oscillating flow and main losses of heat and power. For the GPU-3 with hydrogen, the average relative errors between the simulated results and the experimental data are 10.76% and 5.86% for the indicated power and the indicated efficiency, respectively. The proposed model can provide transient information of pressure, temperature, Reynolds and Nusselt numbers, which are key parameters in the Stirling engine. The transient characteristics and the spatial distributions of Stirling cycles are investigated based on a 100-W prototype. The results show that the pressure drop on the regenerator is more than 95% of the total pressure drop, and increases almost linearly with the rotary speed. Limited amplitude change and nearly axial distribution are observed on the gas temperature of the regenerator. The pressure-volume diagrams predicted by the proposed model are close to the experimental data, indicating that the presented model predicts the transient performance of Stirling engines with reasonable accuracy.