Oil droplet behavior with the position of a muffler discharge hole in the shell of a rotary compressor

Abstract

In this study, high-frequency visualization in the compressor shell via optical glass was performed to confirm inner flow. Visualization experiments were conducted under actual operating conditions (suction pressure = 0.99 MPa, discharge pressure = 2.29 MPa, operating speed = 40, 60, 80 Hz) by using a calorimeter. Most oil droplets transferred to the upper cavity were observed at the coil winding area around the muffler discharge hole. Oil droplets released from the muffler hole collided with the lower face of the motor, because of the high discharge speed and the short distance between the motor and the muffler. In this process, a part of these oil droplets were directly induced into the coil winding area. According to the above-mentioned results, the vane installation to reduce the Oil circulation ratio (OCR) was considered through Computational fluid dynamics (CFD) simulation. The vane was installed inside the coil winding area around the muffler hole. As a result, the oil droplet velocity was decreased by vane, and an OCR reduction effect from 1.2 to 1.8% was predicted.