Modeling of the thermodynamics, kinematics, and dynamics of a beta Stirling engine
Résumé
A beta Stirling engine is a rather complex thermodynamic system that is not in thermal equilibrium. The working piston
is driven by the change of pressure in the cylinder. The change of pressure itself is the result of the change of
temperature of the inert working gas enclosed in the cylinder. The temperature change of the working gas can only be
calculated by accounting for the heat transfer in gas and solid phases and if the motions of the displacer and working
piston are known. The challenge lies in the modeling of a Stirling engine involving multiple physical models that are
coupled. The most important hurdle is to study these physical models in interaction. In this work, a model of a free
piston beta Stirling engine developed using COMSOL Multiphysics is presented. The model is composed of a conjugate
heat transfer module and a module for the mechanical system dynamics (COMSOL Multibody Dynamics Module).
Conjugate heat transfer corresponds to the combination of heat transfer in solids and gases. The model is used to
provide some guideline on the materials requirement and for improving the dynamics of the Stirling engine.