Prediction of Slugging-Induced Cylinder Overpressures

In typical refrigerant compressors, peak cylind er pressures under liquid slugging conditions are as high as 10 times the peak pressures during the normal operation. In this paper we model this phenomenon by considering the compression process with a separated gas and liquid media in the cylinder. Two cases of this model for various liquid fractions are simulat ed. Even though time histories corresponding to both cases are sl ightly different, both models yield very high peak pressures, similar to those measured, when the compressor is "pumping" mostly liquid. Various aspects of the problem are discussed here. NOMENCLATURE A flow area b slider-crank length C coefficient of discharge gc gravitational constant k ratio of isentropic specific heat capacities m mass flow rate n polytropic index