A Research of Scroll Compressor Working Process Computer Simulation and Testing

Thi~ paper is baaed on the working principle of scroll compressor and after investigating the ga~ flow condition, in especial analysis the gas leaking situation between two scroll parts mutual gearing, which influence the compressor performance very much. The working process calculating model is set up, employ the soroll compressor geometric parameter, size~ error of parts manufactured as well ae compressor operating condition, the main performance parameter of scroll compressor can be calculated. The results of computer simulation model compare with e%perimental 1 the results are satisfied, INTRODUCTION In recent years the high efficiency compressors are required as the technology development and the energy shortage, although more ef£orts have been made to improve the efficiency and reliability of the traditional reciprocating compressor. The scroll compressor ha~ inherent advantages, such as high effic~nc~ quiet operation, liffht weight and small size. So it is popular for the refrigerating applications and the other small size compressor increasingly. In this paper, the character of gas flowing in scroll compres~or is analyzed on the basi~ of the principle of scroll operating, and the method of calculating the tangential leak in the mesh position of scroll vane profile is given, then a mathematical model of describing the working process is established, by means of computer, the performance parameters are calculated, at last, the experiment on air compressor is made, the calculation results are consistent w~th the experimental data very well. The results of this paper are useful for optimization design of scroll compressor. WORKING PROCESS ANALYSES The main components of the scroll compressor are the fixed scroll, orbiting scroll, anti-rotation ooupling, crankshaft and crankcase. There are the outside suction port and the outside discharge port in fixed scroll as shown in Fig. 1, the inside suction ports are located at the vane profile termination,the ins~de dischar~e ports are located at the vane profile start.The area of the inside suction ports varies with the crakshaft rotation periodically.The compression pockets begin to discharge after the discharge angle,the area of inside discharge ports increases unt~l the inside discharge process completing. The gas ~s i~ from the outside suction port,then it gets into the suction pookets tangentially through the inside suction ports, after compressed,it gets out of the displacement volume tangentially through the inside discharge ports, then enters the central pocket,at laat,it gets out of the compressor axially through the outside discharge port. In order to analyzing clearly we divide the working process into five st?ges: the steady suction,suction closing,compress~on,initial discharge , steady discharge stage. In steady suction stage,the displacement volume increases from zeroto the maximum~he crank angle range is broad and the suction time is long. In suction closing stage,the volume begins to decrease gradually, but the inside suction ports are not closed off, so the gas return~ng phenomenon arises and the pressure of the closed pockets is hieher than the nom~nal suction pressure, this makes the volumetric efficiency increase. In compression stage, the leakage has main influence on the compressor efficiency. In initial discharge stage, the compressor starts to discharge forcedly, the gas scurries through the inside discharge ports when the pocket pressure is different from the central pocket's. In steady discharge stage, the gas gets out of the compressor, the effective area of the outs~de discharge port decreases because of the orbiting scroll interference, so the discharge velocity increases.