| Scroll compressors are widely used in air-conditioning systems of large equipment such as airplanes,tanks,and electric vehicles due to their high efficiency and energy saving,compact structure,low material and low noise,stable operation,and good variable speed characteristics.In the past,scroll compressors for vehicles were driven by internal combustion engines,and the spindle speed was in the range of 3000rpm-6000 rpm,while scroll compressors for electric vehicles were driven by brushless DC motors with a maximum speed of more than 10,000 rpm.The increase in speed deteriorates the working environment of the compressor's moving and static scrolls,and increases the manufacturing requirements for the moving and static scrolls of the scroll compressor.It is urgent to explore and analyze the flow state of the cold medium in the meshing process of the moving and static scrolls.Therefore,studying the compression flow characteristics of the cold medium in the orbiting and static scrolls is one of the key issues affecting the design and manufacturing of the orbiting and static scrolls.This subject is a sub-project of the "Technology Boosts Economy 2020" key special project of the Ministry of Science and Technology.The thesis is aimed at a 36 cc scroll compressor developed by a company in Guizhou,using R134 A refrigerant as the flowing medium to study the meshing process of moving and static scrolls The flow characteristics of the cold medium in the flow field of the moving and static scrolls and the effect of the flow field on the moving and static scrolls are investigated.The specific content is as follows:(1)Use ANSYS fluent software,adopt 2.5D dynamic grid technology to set the flow field grid deformation,use R134 A refrigerant as the flow medium to establish the internal flow field analysis model of the scroll compressor,and analyze the flow field of the scroll compressor dynamic and static scroll disc Obtain the pressure,velocity,and temperature distribution of the flow field.The pressure distribution in the working chamber is relatively uniform and symmetrical in the center;the speed distribution is uneven and asymmetric,the speed at the gap is the highest,there are vortices in each compression chamber and the suction flow channel;the temperature distribution in the chamber is uneven,and the temperature near the center chamber is the highest;Leakage is the main cause of uneven distribution of pressure field,velocity field and temperature field in the working chamber.The pressure difference between the inner and outer wall surfaces of the scroll teeth mainly exists in the area corresponding to the middle compression chamber,and the pressure difference between the beginning and the end of the scroll teeth is relatively small.(2)When the scroll compressor has an inlet pressure of 0.21 MPa,an outlet pressure of1.22 MPa,and a speed range of 7200-10800 rpm,the pressure in each compression chamber in the flow field increases with the increase in speed,and the pressure difference between adjacent compression chambers increases.The average temperature and average flow velocity in the working chamber,exhaust temperature,leakage rate,inlet and outlet mass flow and fluctuations all increase with the increase of speed.The gas force,axial gas force and overturning moment of the orbiting scroll in the X and Y directions under the action of the flow field all increase with the increase of the speed,and the fluctuation amplitude is also increasing.At 10800 rpm,the fluctuation amplitude is 384 N,267.7N,595N·mm respectively.(3)According to the internal flow field analysis data,the one-way fluid-structure interaction method is used to analyze the stress and deformation laws of the orbiting and static scrolls plates,with emphasis on the deformation characteristics of the anodized orbiting plate.The research results show that the difference of the deformation effect of the flow field on the orbiting scroll and the aluminum substrate after anodization is not obvious,and the difference reflects the wear resistance.The maximum deformation of the tooth top of the compression cavity area corresponding to the moving and static scroll teeth is 48.26 and 57.01 when the radial deformation occurs,and the maximum deformation of the tooth top and the axial deformation is 45.16 and 44.53 respectively.The radial deformation of the scroll teeth is affected by the pressure difference and the temperature difference,and the axial deformation is mainly caused by the temperature load.The deformation distribution of the scroll teeth under the coupling action of temperature,pressure and inertial load is similar to that when the temperature acts alone,and the temperature influence is the largest compared with other loads.The deformation of the scroll teeth mainly affects the radial meshing gap between the compression chamber and the suction chamber,so that the axial gap at the beginning of the scroll teeth becomes smaller.Through the above research,this subject deeply explores the flow law of R134 A refrigerant in the compression process of moving and static scrolls,which is different from the traditional simulation calculation method of ideal gas.Furthermore,the influence of the R134 A refrigerant flow field on the surface anodized orbiting scroll is studied,which provides theoretical support for the design and manufacture of the scroll,which has important engineering guiding significance. |
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