Combining dynamic and thermodynamic models for dynamic simulation of a beta-type Stirling engine with rhombic-drive mechanism

The present study is aimed at development of a dynamic model for the beta-type Stirling engines with rhombic-drive mechanism. Dynamic simulation of the engine is carried out under different operating and geometrical conditions by connecting the dynamic model to the existing thermodynamic model [23]. In the connection, the instantaneous gas forces exerted on the piston and the displacer are determined from the gas pressures in the expansion and the compression chambers with the help of the thermodynamic model. Once the gas forces are obtained, the dynamic model is used to determine the positions, velocities, and accelerations of the components of the engine at the consecutive time step, and then the gas pressures in the expansion and the compression chambers can be updated by the thermodynamic model. In this manner, transient variation in rotational speed of the engine during the hot-start period and the performance curves of the engine indicating the dependence of the power output and the thermal efficiency on the rotation speed can be predicted. In the present study, the effects of the major geometrical and operating parameters on the steady-state rotational speed, maximum power output and thermal efficiency have been evaluated thoroughly in a comprehensive parametric study.