COMPUTER AIDED DESIGN OF MULTICYLINDER RECIPROCATING COMPRESSOR

JOSEPH CHEN-HSIUNG YANG, Purdue University

Abstract

A simulation model for multicylinder reciprocating compressors has been developed. The model is derived from the first law of thermodynamics. In establishing the energy balance principle, an index method has been employed to compute the heat exchange rate. This method correlates the heat exchange rate with the compressor indicator work. Also, it is simple to use and effective in dealing with the heat transfer phenomena in compressor processes. Along with the derivation for the multicylinder compressor model, a characteristic cylinder simulation technique is used to reduce the computation effort. The technique is proven to be reliable in predicting the multicylinder interaction in the plenums. Because of the complexity of the derived model, the compressor model is able to predict the behaviors in the valve spring pockets. The pressure changes in the valve spring pockets prove to be important in valve dynamics. The model has provided a good opportunity to look closely into the detail changes in designing compressor valve systems. Along with the derivation of the semi-analytical compressor model, an efficient test stand for a test compressor has been constructed. The test stand is used to collect performance data for the test compressor. Data are collected through well-calibrated transducers, and are processed by computerized data-processing equipment. The measured data are collected from the test stand under normal operating conditions. They are used to determine the empirical parameters in the derived mathematical model, as well as to validate the simulation model. After the simulation model has been validated, it can be used to evaluate the compressor performance. The simulation model then becomes useful for compressor designs. Three design parameters have been studied in an attempt to improve the compressor performance.

Degree

Ph.D.

Subject Area

Mechanical engineering

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