Study of Free Piston Vuilleumier Heat Pump : Performance Characteristics of Prototype Machine during Forced Vibration

Abstract

Dynamic motion of displacers and basic performance characteristics of a free piston Vuilleumier heat pump(FPVM)during forced vibration were investigated experimentally and compared with 2nd order simulation results. One of a pair consisting of one hot and one cold displacer was driven by a linear motor. Sensitivity studies were conducted with respect to key operational and environmental parameters such as driving frequency, hot gas temperature and motor input power. The dependences of the phase angle and strokes of the displacers on the basic performance of the Vuilleumier heat pump were also examined by driving both displacers of the FPVM prototype machine in order to investigate the performance characteristics of the FPVM operated at various phase angles and strokes. The dependence of the phase angle on the driving frequency of the hot displacer was the reverse of that on the driving frequency of the cold displacer. It was found that the simulation results were qualitatively in good agreement with the results of the experiments.