Some aspects of laboratory testing and computer modelling of two-stage compressors with inter and after-cooling

Abstract

Laboratory testing and computer simulation of a two-stage reciprocating air compressor with inter and after-cooling was undertaken with the purpose of studying the physical processes occurring in the compressor and obtaining information useful for design purposes. The testing includes measurements of instantaneous temperature and pressure in suction and delivery chambers and interconnecting pipes in both cylinders, instantaneous torque and average quantities, during the steady and transient state operation. Results are presented and the problems are discussed. The suitability of the micro-thennocouple for measurement of instantaneous temperatures, its dynamic behaviour and strength limitations, as well as mounting and calibration problems are considered. The measurement of pulsating pressure by means of piezoelectric and capacitive transducers in combined use are presented with specific reference to the effect of transducer location. Results are reported of the computer modelling of the thermodynamic processes including the unsteady gas flow in the piping system with friction and heat transfer effects, and comparison made with experimental data. Some practical implications are discussed of the testing and computer modelling upon desig