Influence of an orifice plate on gas pulsation in a reciprocating compressor piping system

This paper presents an investigation of the influence of the orifice plate parameters and installation positions on the attenuation of gas pulsation in a reciprocating compressor piping system. The acoustic wave theory and transfer matrix approach were applied to establish the simulation model, in which the valve chamber was assumed to be the pipe-volume-pipe element. Based on the model, the effects of the size and installation positions of the orifice plate on the gas column natural frequencies and pressure pulsation amplitudes were analyzed for the discharge piping system of a two-stage reciprocating air compressor. A test rig was built to validate the simulation results. The gas column natural frequencies and pressure pulsation amplitudes at different locations of the piping system were measured to verify the model. A favorable agreement was noted, with a maximum error of 2.1% for the natural frequencies and 6.3% for the pulsating amplitudes. The influence of the orifice plate on the gas column natural frequency varied according to its position and parameters. The results showed that all orders of natural frequencies decreased slightly as the inner diameter of the orifice plate decreased when the orifice plate was installed downstream of the vessel. However, the distribution of the gas column natural frequency changed when the orifice plate was installed upstream of the vessel. The pressure fluctuations in the piping system could be attenuated substantially by placing an orifice plate of reasonable parameter downstream of the vessel, within a distance of 0.4 m. The degree to which the orifice plate could attenuate the gas pulsation varied under different operating conditions. However, its attenuation effect was more sensitive to the compressor speed than to the discharge pressure.