A Computationally Efficient Hybrid Leakage Model for Modeling Leakage in Positive Displacement Compressors

An empirical frictional correction factor to the isentropic nozzle model has been developed for application to leakage modeling in scroll, rotary and other similar compressors. This correction factor is derived by calculating the leakage mass flow with a compressible, variable area, real gas properties model and then correlating the ratio of this flow to the isentropic nozzle model prediction. The ratio of flows is correlated to the Reynolds number, a characteristic length and the leakage gap width. A representative selection of fluids and geometries are employed, and the correlations predict at least 93% of the detailed model results within an absolute error band of 20%.