Fluid Flow in the Oil Pumping System of a Hermetic Compressor

Abstract

This work deals with the investigation of the oil pumping system in hermetic compressors for refrigeration application. The oil pump which is used for this study consists of two pumping areas: the lower pumping area with a pick-up tube and an eccentric bore, and the upper pumping area with a helical groove. This study focuses on the helical groove in the upper pumping area. To analyse the fluid flow in the helical groove, a numerical approach is introduced. In this approach the Navier-Stokes equations are adapted to the problem and are solved by using the finite volume method. Compared to analytical models, this method is able to obtain the flow field in the cross section of the helical groove at higher resolution. The higher geometrical resolution also enables the analysis of the flow in the small gap between the rotating crankshaft and the stationary wall. The present method is used to quantify different operating parameters on the oil mass flow rate.