Pressure Pulsations, Transfer Matrix, Impedance, Simulation
A 3D calculated impedance transfer matrix method has been developed and demonstrated to provide accurate and efficient prediction of pressure pulsations in positive displacement compressors. The method is easily incorporated into 1D compressor simulation models, where a single impedance matrix, normalized to density and speed of sound, can be used to model all compressor running speeds and operating conditions. The general transfer matrix or “4 pole” method is documented by Bilal, et al (2010) where the hybrid approach used here is also introduced. More recent developments of this method are presented by Novak and Sauls (2012). This paper describes how the model has been integrated into a family of 1D thermodynamic simulation programs used for design and analysis of reciprocating, scroll and screw compressors. A review of how the model compares to test results for a twin screw refrigeration compressor is provided. In addition, we show one example of the type of design study that can be carried out using the 1D simulation with the hybrid model.