CFD Simulation Study On The Internal Working Substance Leakage Of Rolling Rotor Compressor

There exit many kinematic pairs and leakage channels in a rolling rotor compressor, it is hard to improve its volumetric efficiency in the case of internal working substance leakage, so researching on leakage characteristics of compressor internal working substance is crucial to improve the performance of compressor. Taking fully enclosed vertical single cylinder rolling rotor compressor as research object, this study analyzes the characteristics of the compressor internal leakage channels and establishes its mathematical models by gap flow theory of hydromechanics, from which single-phase lubricant leakage simulation on the sliding vane & sliding chute clearance and the rotor & end cover clearance and oil-gas two-phase leakage simulation on radial clearance and vane/end cover clearance are carried out by using CFD numerical simulation methods. As a result, the simulations obtain the maximum clearances in response to the compressor design parameters. In addition, flow characteristics of oil-gas in clearance are not in the state of uniform mixing but in the state of stratified flow under the action of the viscosity, oil slicks form into waves and lubricants accumulate in the middle section of radial clearance. The main contents of this research are as follows:(1) Introduce the structure characteristics and working principle of rolling rotor compressor, establish the pressure and volume mathematical models of its suction chamber and compression chamber and the kinematics models of the sliding vane.(2) Build the mathematical models of the compressor internal leakage channels by analyzing geometrical structure characteristics and using to clearance flow theory of hydromechanics.(3) Present the single-phase lubricants CFD simulation models of the sliding vane & sliding chute clearance and the rotor & end cover clearance and the oil-gas two-phase CFD simulation models of the radial clearance and the sliding vane & end cover clearance. The results suggest that the maximum clearance of each leakage channel should be limited to assure that the volume loss caused by leakage less than 5%, for example, the maximum radial clearance should be less than 27μm, the maximum sliding vane & sliding chute clearance should be less than 25μm,the maximum sliding vane & end cover clearance should be less than 35μm, the maximum rotor & end cover clearance should be less than 31μm.(4) Analyze the leakage characteristics and flow characteristics of fluid in kinematic pair clearance of compressor. The findings indicate that the flow characteristics of oil-gas two-phase fluid in the clearance are not in the state of uniformly mixing.(5) Perform leakage measurement experiment by dynamic equivalent leakage experiment device of rolling rotor compressor under the dynamic change of different factors such as clearance values and rated speeds. The simulation method of this study has been proved correct by the comparison of test results and simulation results.