Adiabatic Analysis of Rotary Displacer Stirling Engine

Abstract

Utilizing analytical models at the initial stages of Stirling engine (SE) development is a common approach since the cost could be excessive when experimental (i.e., building prototypes) or even numerical (i.e., using Computational Fluid Dynamics (CFD)) approaches are taken first. One of the well-known analyses in this area is the adiabatic analysis that assumes working fluid to be an ideal gas, and adiabatic expansion and compression processes in the power cylinder. Although adiabatic analysis neglects pressure loss in the cycle, it still predicts operating envelope and performance with a better accuracy compared to isothermal (Schmidt) analysis. This study considers the adiabatic analysis that was originally developed for conventional, reciprocating displacer SE configuration, and aims to adapt it for an innovative, rotary displacer SE configuration. The analysis enables to present pressure-volume diagrams, and estimates the amount of generated work and the efficiency. The results, when compared to that of the ideal Schmidt analysis, indicate up to 4.6% lower values of the generated work, suggesting a significant difference between the two ideal assumptions.