Research On Sealing Performance Of Oil-free Scroll Compressor Tooth Top Based On Surface Texture

Oil-free scroll compressor is more and more favored by the market because of its pure compression working medium,which meets the requirements of the industry that needs clean working medium at present.Oil-free scroll compressor has also been rapidly developed.In addition,scroll compressor also has the advantages of compact structure and high efficiency,so that oil-free scroll compressor is widely used in industry,transportation,agriculture and other industries,has a broad application prospect.Because of its structural characteristics,the leakage problem of oil-free scroll compressor is still a very important factor affecting its efficiency.Therefore,it is necessary to study and optimize the leakage problem.According to the above problems,this thesis takes oil-free scroll compressor as the research object,establishes its geometric model and mathematical model,and analyzes its leakage characteristics.Based on the surface texture method,a three-dimensional model of fluid clearance was established to simulate and analyze the functions and effects of sealing strips with surface texture in reducing friction and leakage of oil-free scroll compressors.The main research and work contents of this thesis are as follows:(1)The geometric model of oil-free scroll compressor is established,and the mathematical model under actual working conditions is established according to the geometric model.Including its heat transfer model and leakage model.The change law of pressure,volume and mass flow with the change of spindle Angle is obtained.(2)Analyze the leakage model of the compressor,calculate the tangential leakage and axial radial leakage of the two adjacent working cavities,and obtain the mass flow curve.The results show that the mass flow rate of tangential leakage is much smaller than that of radial leakage,and the main leakage form of compressor is radial leakage.The variation range of tangential leakage gas mass flow rate is much smaller than that of radial leakage.(3)Analyze three different sealing structures,establish three kinds of leakage mathematical models,and calculate and analyze the models.Through comparison,it is concluded that the sealing structure with surface texture has the smallest leakage,followed by the sealing structure of the sealing strip,the leakage of smooth seal is the largest.(4)A three-dimensional model of surface texture with different shapes and depths was established.The boundary conditions of the model were set so that the pressure inlet and outlet of the model were the average pressure in the second and third compression chambers,respectively.The simulation results show that: the force of the model with surface texture on the bottom of the scroll disk is greater than that of the model without surface texture,and the force of the model with elliptical surface texture is the largest.The outlet mass flow rate of the model with circular surface texture is smaller than that of the model without surface texture.(5)The simulation results are verified by experiments.The circular surface texture is processed on the seal strip,and the sealing strip without surface texture and the sealing strip with surface texture are installed in the sealing groove of scroll teeth for comparison test.The optimization effect of surface texture on leakage,friction and wear of oil-free scroll compressor was verified by measuring the mass flow at the compressor outlet and compressor efficiency under different working conditions.