Investigation of the Mass Flow Sources in a Multi-Cylinder Compressor Using Frequency Response of Pressure Pulsations in the Suction Manifold

Linear acoustic plane wave theory and a four pole parameter formulation are used to derive and solve the governing inhomogeneous equation for the forced pressure response in the simplified manifold model. The equations for estimating gas pressure pulsations in the annular cavity connected to an anechoic inlet pipe are presented. Complicated interactions between multiple cylinder valve ports in the suction manifold produce unexpected changes in the frequency response conditions for changes in the operating speed, and hence, the flow rate characteristics through the valves. From the addition of the delayed time for opening valve in the mass flow rate profiles and the comparison of the gas pulsations from experiment with those from simulation, the maximum strokes of the piston and the delayed times for opening valve can be estimated without solving the valve dynamic and thermodynamic equations. By applying the mass flow rate sinks at each valve as identified, the correlation between analytical and experimental results is shown to be much better than if the idealized, kinematically obtained source functions are used instead.