New polytropic model to predict the performance of beta and gamma type Stirling engine

A new Polytropic Stirling Model with Losses (PSML) is proposed to predict performance of Beta or Gamma type Stirling engine. A bypass was added between the compression and expansion volumes and polytropic processes have been considered in these volumes. Shuttle heat exchange and mass leakage in the gap between the displacer and the cylinder have been considered at the same time step. Various losses have been coupled in the model, including regenerator imperfection, heat conduction, fluid viscosity et al. which interact each other as they are calculated in the same time step.