Oil flow at discharge valve in a scroll compressor

Abstract

This work focuses on high speed visualization of the three reed valves in a scroll compressor. The visualization was performed to obtain qualitative description of the oil flow in terms of morphology and breakup and to quantify the droplet size and velocity distribution functions both for start-up and cyclic operation conditions. It was observed that at startup, part of the oil film between the valve and its seat is first pushed out before the valve can start moving, after that the valve starts opening and the film is stretched so that liquid columns in organized spacing appear and are blown out by the gas originating the droplets that form a mist. During steady operation of the compressor, no oil film breakup was clearly observed at the valve-seat interface, suggesting that the oil droplets might be generated from vapor shear through the orifice since there is a recess that can hold up oil inside the orifice.