Leak Paths Research Articles

Application of x-rays to metallurgy

This paper illustrates the use of computational fluid dynamics (CFD) to analyze selected features of a refrigeration screw compressor. Specifically, we consider leakage flows between the housing and the tips of the male rotor and through the blowhole, a leak path formed by the two rotors and the housings together. In addition to revealing the nature of the flows in these leak paths, this study provided data for the development of simplified leakage models that can be used in an existing one-dimensional thermodynamic simulation.Calculations were carried out for leakage flow through specific geometries representative of the radial clearance between the screw rotors and the compressor housing as well as for the blowholes of two selected rotor pairs. In the case of the radial leak path analysis, the geometry of the leak gap for a particular male rotor is used. Cases with and without relative motion between the walls were analyzed. When there is relative motion, the velocities comparable to the tip speed of the rotor and twice that level are studied. For the blowhole calculations, only models with stationary walls are considered. In all cases, calculations presented here are for refrigerant only; oil is not considered in this study.Computed flow rates are compared to those calculated by the relatively simple model used in our one-dimensional thermodynamic simulation. The result is a set of correction factors that result in leakage flows in the simulation being better aligned with those computed using the more detailed CFD analyses.