A Nonlinear Non-dimensional Dynamic Model for Free Piston Thermal-lag Stirling Engine

Abstract This study is aimed to develop a theoretical model to determine criterion of instability and predict performance of a free-piston thermal-lag Stirling engine (FPTLSE). Experiments are conducted to verify the theoretical predictions partly. In the present study, a nonlinear model consisting of non-dimensional equation of motion and energy equation are derived. These governing equations are solved simultaneously by employing a multi-scale method, in which zero-order approximate solutions representing piston motion and temperature variation are obtained. Results show that the FPTLSE can be a self-started engine that may be able to start automatically after heating. In addition, the predictions by the theoretical model are found to agree closely with the experimental data for the oscillation of the piston. The present model is capable of predicting the dynamic behavior of the engine.