Study On The Structural Characteristics Of A New Type Of CO₂Compressor

Due to the enhancement of the people environmental protection consciousness, the studyof the CO₂refrigerant is more and more strong interest in thermal physical properties andtransmission characteristics. The CO₂refrigerant compressor has been put forward newrequirements with the development of these studies.In this paper, through the analysis of the thermal physical properties of CO₂refrigerantand the mixture of PAG oil and CO₂refrigerant characteristics, the new CO₂refrigerantcompressor has been designed. The compressor shell strength has been analyzed with finiteelement analysis software-ANSYS and contrast to the experience. The compression chamberof the compressor internal leak path has also been analyzed with FLUENT software. Themain research subject and conclusions are as follows:（1） Physical properties and transmission characteristics of CO₂refrigerant have beenanalyzed and the results show that the CO₂has two important features: The CO₂compressorhas the characteristics of high working pressure compared with other refrigeration compressor,so the demand to the strength of compressor shell becomes very high; Compared with otherrefrigerants, the viscosity of CO₂refrigerant is more than others. This helps to refrigerantchoose oil to that viscosity is not very big, which reduced oil’s standards. Through theliterature collection, concludes that the physical parameters of the mixture CO₂and PAG oil,such as CO₂solubility in the PAG oil, CO₂and PAG mixture density, as well as CO₂andPAG mixture motion viscosity and for the future work laid a foundation.（2） Introduces the basic structure and its working principle of the new type compressorand the compressor theory volume and clearance volume had been analyzed and calculated,and reaches the calculation formula of the true size capacity. In a given the small size of thecase, the theory has a capacity of0.0059m3, which is more than the largest small pistoncompressor theory volume （0.00046m3）. For the compressor design a feasible power system,the calculation formula of the torque of this compressor are get by the calculation. Throughthe contrast analysis with piston compressor in certain conditions, the new type of compressoris more outstanding in volume and the energy consumption than all piston compressors.（3） The compressor shell strength has been analyzed, which used the ANSYS finiteelement analysis software and get the weak link of strength of the compressor, and makes thecorresponding improvement and with experience to validation.（4） Compressor compression chamber leak path has been simulated, which usingFLUENT fluid analysis software. Through take five state points in the process of compression, leakage formula of the CO₂and PAG mixture are fitted out, and according to the formula ofCO₂solubility in the PAG oil is deduced from the leakage rate formula of CO₂refrigerant,and gets the conclusion that the leak path5and6is the key leak place.