Split-type free-displacer Stirling refrigerator design using linear network analysis

Abstract

A linear network analysis is developed for the system design of split-type free-displacer Stirling refrigerators. The dynamics models are derived to describe the input/output relation of each component by use of the governing equations in conjunction with linearization and approximation. By connecting the equivalent circuits of the components together, a linear network consisting of a fluid network and a displacer network is obtained. The fluid network accounts for the propagation of gas flow induced by the pressure wave; while the displacer network accounts for the displacer motion induced by the pressure force exerted on the displacer. Two transfer functions are further derived for the displacer motion and the gas pressure of the expansion space with respect to the piston motion. The system performance is then evaluated from the frequency response of the transfer functions by using the sinusoidal signal analysis. The performance prediction of a split-type free-displacer Stirling refrigerator using the linear network analysis is shown to be satisfactory.