Simulation And Experimental Study Of The Rolling Piston Compressor Refrigerant Leak Radial Clearance

Internal working medium leakage is one of the important influences on the volumetric efficiency of rolling-piston compressors,and the radial clearance leakage in rolling-piston compressors is the most of these main leakage pathes,which means the study on the character of the radial clearance leakage is of great significance.In this work,the vertical single cylinder fully enclosed rolling-piston compressor is the research object and its radial clearance leakage character is studied.Based on analysis about the structure principle of rolling-piston compressors and force analysis about the vane and rolling-piston,the theoretical formula of the oil film seal angle is established.Moreover based on the experimental measurement of the oil film seal angle and asymmetry degree of the oil film,the CFD simulation model of the adial clearance leakage path is also established.Then the orthogonal experiment proceeds with the CFD simulation model,in which these four factors,radial clearance,differential pressure,oil viscosity and eccentric shaft speed,are considered in the significance analysis.Finally the significance level of four factors on radial clearance leakage influence is proposed and the leakage forming process of the radial clearance leakage path is analyzed.The main contents of this article are as follows:(1)The research status at home and abroad about rolling-piston compressor leakage is introduced first of all.Main leakage pathes of rolling-piston compressors are analyzed and their volume and pressure are computed.The theoretical formula of the oil film seal angle is proposed with the force analysis about the vane and rolling-piston(2)The theoretical calculating value of the oil film seal angle is solved by MATLAB.Then the motion State image of the oil film under ordinary pressure is catched by high-speed camera.Moreover the experimental values of the oil film seal angle and asymmetry degree of the oil film are acquired by image recognition technology based on self making MATLAB programs.By comparing them with the theoretical calculating values,ultimately,the oil film seal angle is 19° and the asymmetry degree of the oil film is 0.4276.(3)Carried out the orthogonal experiment of three factors simulation,using FLUENT to simulation,obtaining the leakage and breakdown time of each test were.Through analysis of variance we obtained The significant influence order of three factors:radial clearance>differential pressure>lubricating oil viscosity.(4)Manufacturing a set of radial leakage simulation observation device,The device has the advantages of good tightness,adjustable clearance,and real-time observation of the variation of the internal fluid in the experiment process.First of all,Through radial clearance,differential pressure,lubricating oil viscosity these three factors to establish 3 factors and 5 levels orthogonal table.Experiments are conducted by means of the experimental conditions given by the orthogonal table,After the experiment,the video will be analyzed by the self-made MATLAB image processing program.The experimental data such as gas leakage and breakdown time are obtained,then,through the variance analysis to analysis experimental data,obtaining the influence level of three factors and the influence order of significance.The simulation results are compared with the experimental results,and the error reasons are analyzed,comprehensive simulation and experimental data illustrate the significant influence order of the three factors,namely,radial clearance>differential pressure>lubricating oil viscosity.(5)On the basis of verifying the correctness and feasibility of the simulation orthogonal experiment,carring out the orthogonal experiment of four factors,obtaining The leakage,breakdown time and volume loss of each test.Through variance analysis obtained the significant influence order of the four factors.The range of each factor is obtained under the condition that the volume loss is less than 5%:radial clearance<35μm,eccentric shaft speed>2000r/min,differential pressure<0.6Mpa,lubricating oil viscosity>50.35mpa.s.Finally,Combined with the two simulation orthogonal test to analysis the radial clearance leakage process.