Simulation of a high-speed hermetic compressor with special attention to gas pulsations in three-dimensional continuous cavities

This study is on the modeling and analysis of hermetic refrigeration compressors for the prediction of thermodynamic performance and gas pulsations. A computer simulation model of a hermetic, reciprocating compressor has been developed to study basic performance and gas pulsations of compressors. The mathematical models are based on the polytropic process assumption for the cylinder process and a linear acoustic model for gas pulsations. To supplement the theoretical model, pressure measurements and valve motion measurements were conducted as fundamental experiments. Thermodynamic and acoustic performances of a prototype compressor were studied using the computer simulation program. A general procedure has been developed to analyze complex acoustic systems composed of multiply connected three dimensional continuous cavities. The four pole parameter concept was used as a fundamental tool for the system analysis. An approach to obtain the four pole parameters of an acoustic system from its pressure response solutions was developed. Pressure pulsations in the suction gas path including the shell cavity resonance effect were analyzed as an application example. For the response solution of the hermetic shell cavity, the eigen-function expansion method was used to model the cavity as an annular cylinder. Design parameter studies for the thermodynamic efficiency improvement of the prototype compressor were conducted using the developed computer simulation program. Special concept mufflers for passive noise control in the suction gas path were studied using advanced features of the simulation program