| Scroll compressors can be used for the refrigeration and compression of air,with their mature design and processing technology,and they have a wide range of applications in production and life.However,in the fields of medical equipment,food processing refrigeration,textile processing,etc compressors cannot use oil lubrica-tion when they compress air and must require clean air.Aiming at the current research situation,working characteristics and existing deficiencies of oil-free scroll compressors,a new oil-free scroll compressor prototype was developed.The mathematic model of oil-free scroll compressor is investigated in detail,and the variable speed performance test is carried out through the built test platform.In this project,a prototype with a displacement of 0.6m~3/min was used to test the established mathematical model and further verify the accuracy of the model.The main research contents include the following aspects:(1)According to the three-dimensional model of the prototype,from the beginning of suction to the end of exhaust,the heat transfer model and the leakage model were respectively considered,and a complete mathematical model was constructed under the actual operating conditions.Fortran and Matlab software programmed by Euler method to get the volume,pressure,exhaust temperature,mass flow with the spindle angle changes.(2)According to the mathematical model established above,the variation of each performance parameter of oil-free scroll compressor under two different operating conditions,leakage and no leakage,is analyzed.Further study on the effect of leakage on the performance of oil-free compressor Affect the law.The results show that:the leakage of the working chamber of the quality of the greatest impact,while the pressure on the working chamber minimal impact.(3)In order to further study the influence of heat transfer and leakage on the performance of oil-free scroll compressor,the change law of performance parameters of the prototype is analyzed under different heat and leakage rates.The results show that heat transfer has the greatest effect on pressure and temperature,while leakage has the greatest impact on the working chamber mass.(4)The leakage model of oil-free scroll compressor is analyzed in detail.Based on the law of mass conservation and gas state equation,two adjacent working chambers are established under two different leakage channels,radial leakage and tangential leakage The size of the leakage,calculated the mass flow rate with the spindle angle changes.The results show that the mass flow of radial leakage is far greater than the mass flow of tangential leakage,and the variation of mass flow in radial leakage is much larger than that of tangential leakage.(5)The new oil-free scroll compressor developed by our company has been tested for the variable speed performance,and then the accuracy of the mathematical model and the rationality of prototype design have been verified.The variation of performance parameters(temperature,displacement,power,voltage and current)of oil-free scroll compressor under different exhaust pressures were tested.The experimental results show that the theoretical simulation and experimental data are close to verify the correctness of the mathematical model.As the speed increases,the temperature,exhaust volume,power showed a clear upward trend.In this paper,a more comprehensive mathematical model has been established for the new oil-free scroll compressor,considering the heat transfer model and the leakage model respectively.The working process model of an oil-free scroll compressor was simulated under the actual operating conditions.The established mathematical model was verified through an experimental test platform that had been built.The experimental test results showed the results of theoretical simulation and experimental testing,with a high degree of agreement,the error between the two is small.This mathematical model has some guidance and reference for the research and performance analysis of oil-free scroll compressors. |
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