Research of Oil-Injected Scroll Compressor Working Process

The working process of oil-injected scroll compressor is analysed in this paper. The thermodynamic and dynamic models arc developed for the oil-injected scroll compressor. The property parameters can be calculated under the influences of the leakage and the friction. The results of computer simulation are coincident with the experiment's. so it is useful to predict the compressor performance. INTRODUcnON Scroll compressors have shown their competitive advantages in the markets of heat pump air-conditioners and refrigerators for their high efficiency, low noise and vibration, small size and light weight. Since the first set of scroll compressor has been developed in China, we devoted to the studies and researches of them, and put them into wide applications. The concept of scroll compressor was first described in the U.S patent in the early 1900s, but was not fully developed in practical application until recently, one of the •mportant reasons for this is due to the leakage losses through the clearances between scroll wraps, as shown in Fig. I, this.can reduce the volumetric efficiency and increase the energy losses. When the pressure differences between two near working pockets are constant, the directly determining factcr of the leakage losses is the size of the clearances, the appearance of the precise production techniques can control the range of the radial clearances within reasonable area, but the axial clearances are connected with the machmg, installing and forces acting on the wraps, furthermore, the radial leakage losses arc much higher than tangential's, so it's necessary to take some measures to reduce the leakage losses. The structure shown in Fig.2 is a very typical mechanical sealing mechanism for this purpose. A sealing element is inserted tightly in the groove machined on the top of the wrap ;o prevent radial leakage, although it can increase the volumetric efficiency, it has its dis·