Abstract
In a reciprocating compressor having close distance between a suction pipe and a suction muffler, great part of refrigerant flowing from the suction pipe is directly sucked into the suction muffler. But a part of refrigerant leaks into the void space in the hermetic shell and contacts with the cylinder, the motor or other high temperature parts. The temperature rise of refrigerant due to this leakage decreases the efficiency of a compressor. Therefore the efficiency of the compressor increases with decrease the amount of leakage.
In this paper, the direct suction ratio (DSR) is defined as the ratio of the flow rate of refrigerant directly sucked to the total flow rate from the suction pipe, and measured with a new technique using digital image processing. The technique developed measures the temporal decrease of visible tracer particles filled initially within the hermetic shell of a compressor visualization model, and calculates the DSR from the rate of concentration decrease. The technique is applied to improve the performance of reciprocating compressor by modifying the shape of the suction pipe which gives higher DSR.
Although refrigerant flow velocity around suction pipe and muffler is required as a fundamental data for further improvement of the performance, there has been no report or paper which measures these data due to the difficulty in insertion of velocity sensor into hermetic shell. In this paper, flow velocity data obtained with a PIV (Particle Imaging Velocimetry) technique applied to compressor visualization model is also presented.
