Research On The Performance Of Compressor In CO₂Transcritical Cycle

Energy-saving and environmental protection has become the theme of refrigerationindustry development. As the core part of cooling and heat pump equipment, Compressorefficiency has a decisive influence on the whole system efficiency. Therefore, optimizingdesign of CO₂reciprocating compressor and CO₂scroll compressor, and then improve theefficiency of the refrigeration system.Based on the thermodynamics and dynamics principles, this paper analyzed thestructure principle and characteristics of CO₂piston and scroll compressor, and set up themathematical model. Through the ANSYS finite element software analyzed theoreticallythe results of numerical simulation on crank rod system and orbiting scroll.In the working process of the CO₂reciprocating compressor, the small head ofconnecting rod has the largest displacement variation, and the maximum stress and strainexists in the small head and big head of connecting rod. For stress concentration of smallhead rod, by changing the size, or the local joints and transition can reduce stressconcentration round. For big head in connecting bolts can choose bigger elastic modulusmaterial to connect big head, and improve the connecting rod strength. In the workingprocess of CO₂scroll compressor, which is up to6⁷MPa gas pressure, the most seriousdisplacement deformation is in addendum of orbiting scroll, and the maximumdeformation is about7.33μm. Dedendum of the orbiting scroll has the biggest stress.Maximum strain is near addendum, and the axial clearance caused by axial strain has thebiggest damage, while tangential strains take the second place, and radial effects are theminimum. For the maximal displacement and deformation of the problems brought bylarge clearance, which can keep the sealing between orbiting scroll and static vortex dishby adjusting locations of orbiting scroll circle in different height.According to the theoretical analysis of two kinds of compressors, this paper canprovide the theoretical material for developing model machine and improving theperformance of CO₂cooling and heat pump circulation.