Calculation of discharge pressure pulsations of a screw compressor using the one-dimensional method of characteristics

This paper presents a method to simulate the discharge process of screw compressors. The calculation is based on the method of characteristics. The main focus is the transient, compressible, dissipative flow through the compressor discharge port. The time-dependent velocity at the outlet is calculated using a circular orifice with time-dependent diameter and is initially validated by an exemplary screw compressor. The one-dimensional model for the working chamber is presented and the transient flow on the discharge side is calculated for different discharge pressures. The calculated results are compared to experimental data.