NUMERICAL-SIMULATION AND EXPERIMENTAL INVESTIGATION OF COMPRESSION PROCESSES OF 2-STAGE, VERY HIGH-PRESSURE RECIPROCATING GAS-COMPRESSORS

To help the design of more reliable and efficient two-stage, very high pressure reciprocating gas compressors, a theoretical model and a numerical code for simulating compression processes in the compressors were developed and validated. The theoretical model considers time-dependent conservation equations of species, mass and energy, the equation of state, kinematic relationships and various convective heat-transfer correlations. The theoretical model was solved numerically. Experimentally, a 207 MPa (30 000 lb/in(2)) very high pressure gas compressor was instrumented for measurements of various transient flow properties. The experimental data were analysed to achieve a better understanding of the compression processes of the compressor as well as for model validation. A parametric study was conducted with the theoretical model and numerical code to investigate the effect of various compressor parameters on the compressor performance. Among the parameters studied, it was found that the dead-end volume had the strongest effect on the performance of the compressor. A reduced dead-end volume would increase the volumetric efficiency and the maximum gas-phase temperature and pressure in the first-stage cylinder.