Dimensional analysis of leakage and mechanical power losses of kinematic Stirling engines

Dimensional analysis is applied to both leakage and mechanical power losses in order to obtain the set of parameters that influence power performance of the kinematic Stirling engine. An empirical model of mechanical power losses is proposed to complete the indicated power model previously introduced by Prieto and co-workers. That approach Is mainly based on the characteristic Stirling number and allows the performance of known prototypes to be analysed from the viewpoint of indicated power, brake power and mechanical efficiency. After showing that similarity criteria call be extended to brake power performance, scaling factors have been derived for typical scaling cases. Some examples show that quasi-static simulation and scaling techniques may be combined to Support preliminary design procedures.