| The new oil-free scroll compressor has the advantages of simple structure,remarkable efficiency and low working noise.In view of the current research status,when the oil-free scroll compressor is running,as the volume of the half-moon-shaped cavity is reduced,during the scroll compression operation,the gas thermal load acts on the scroll,the combined effect of the temperature field and the pressure field will affect the operating efficiency of the oil-free scroll compressor,so how to obtain accurate pressure and temperature field distribution is particularly important.A one-dimensional heat transfer model of vortex teeth was constructed based on numerical heat transfer and meshless method,and a two-dimensional steady-state heat transfer model of scroll teeth was constructed using meshless method.The temperature field distribution of scroll teeth was simulated by MATLAB;The fluid flow field in the cavity of the oil-free scroll compressor was simulated and analyzed,and the variable-speed performance test was conducted through the established test platform to verify the accuracy of the model.In this paper,the general research on the temperature field and fluid flow field of the new oil-free scroll compressor includes exploring the following aspects:(1)The basic theory of the oil-free scroll compressor profile is described,the volume of each working cavity is calculated,and the volume change law is obtained according to the rotation angle of the main shaft and the volume change rate of the cavity.(2)A one-dimensional non-steady-state heat transfer model of the scroll teeth is constructed based on the control volume method.An iterative formula for calculating the scroll teeth was developed,and a one-dimensional distribution curve of the temperature field of the scroll teeth was calculated by writing a program in MATLAB.(3)The meshless method is used to construct one-dimensional and two-dimensional heat transfer models of the scroll teeth,and the discrete equations and node temperature value formulas are obtained.Gaussian integration is used to determine the regional Gaussian integration network and coordinates.The program is written using MATLAB to solve the one-dimensional steady-state temperature field distribution and the two-dimensional steady-state temperature field distribution of scroll curve.(4)The cavity of the oil-free scroll compressor is meshed in one working cycle.The staggered grid technology is used to solve the problem that the momentum source of fluid flow is not reflected in the discrete equation.The pressure field is solved by the PISO algorithm.Finally,the program of Open FOAM is used to calculate the temperature field,pressure field and velocity field distribution of air in the compression chamber of the scroll compressor.(5)A new variable speed performance test system platform for the new oil-free scroll compressors was set up,and the performance parameters(temperature,pressure,power)was tested under different operating conditions.The test data shows that the simulation results of the pressure distribution and exhaust temperature in the cavity are not much different from the test results.As the spindle speed increases,the temperature and power clearly show the upward trend. |
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