Abstract
A linear analysis model for a free piston Vuilleumier heat pump(FPVM)was constructed to derive closed from solutions for the operating frequency, phase angle and displacer strokes during self-excited operation and forced oscillation. Using the linear analysis, conditions for self-excited operation and the effects of connecting the hot and the cold displacers by a spring on the dynamic motion of the displacers and the FPVM performance were investigated. Energy flow in the FPVM was also pbtained. A simple 2nd order isothermal simulation combined with the linear analysis was developed which enabled calculation of the FPVM performance characteristics. It was found that the simulation results were qualitatively in good agreement with the experimental results during self-excited operation. Simulation was used to calculate the dependence of the dynamic motion of the displacers and the FPVM performance on the spring constants, displacer masses and damping coefficients.
