Research On Performance Prediction Model Of Scroll Compressor Considering Friction And Leakage

In recent years,with vigorous investment in processing technology and optimization research,the energy efficiency,reliability and cost performance of scroll compressors are better than the same displacement and lower price rotor compressors,making scroll compressors in air conditioning,Heat pumps,frozen cold chains and other industries are increasingly used,and their market share has grown steadily.However,due to its own structure,manufacturing cost and high failure rate of variable capacity scroll compressor,the application limitations of scroll compressor are obvious;Moreover,friction,leakage and variable compression processes are the main factors influencing the performance of scroll compressors,and also the key points to establish accurate performance evaluation models.In order to evaluate and predict the performance of the scroll compressor comprehensively and rapidly,and calculate the physical parameters of the exhaust gas of the scroll compressor accurately,based on the theory of heat transfer,thermodynamics and variable compression process,a relatively perfect mathematical model for the prediction of the performance of the scroll compressor is established in this paper,which can provide theoretical basis for the optimization of the performance of the scroll compressor and the effective reduction of the failure rate.According to the analysis of the structure and motion principle of the scroll compressor,it is known that friction and leakage are the main factors affecting the performance of the scroll compressor.Therefore,this paper first establishes a friction loss equation based on the mechanical balance of the compressor components based on the mechanical analysis and friction and wear analysis of the scroll compressor components,and calculated the friction loss caused by each friction pair of the movable scroll with the crankshaft angle;Based on the principle of nozzle viscous gas flow,the relationship between the amount of compressed gas leakage and the change of its heat with the crankshaft angle when the dynamic and static vortex clearances are unchanged is obtained.Secondly,according to the gas flow state and heat transfer principles in the compression cavity,the heat transfer between adjacent compression cavities through the wall surface and the relationship between the frictional heat transfer and the rotation angle of the main shaft based on the tribological principle are analyzed in detail;After analyzing the gas compression process,comprehensively considering the effects of leakage and heat transfer on the scroll compressor,based on the ideal gas variable compression,and based on the principle of variable mass thermodynamics,the variable compression process equation of the scroll compressor was established,and the calculation model of the variable compression process index suitable for the actual working conditions is derived,as well as the change law of the gas mass change process index and the heat transfer process index during the operation of the scroll compressor.The calculation results show that the process index of gas mass change caused by leakage during compression is positively correlated with the leakage rate,the heat transfer process index change shows an exponential attenuation law,and the multivariable compression process index of scroll compressor with combined effects of leakage and heat transfer increases first and then decreases.In a complete compression cycle,the compression process index is a variable value,and the change of gas mass in the compression chamber has a great influence on the process index.The results can provide a basis for accurately predicting the performance of scroll compressors.Finally,based on the effects of friction,leakage and variable compression on the performance of scroll compressors,a more accurate performance prediction model is established based on the principles of fluid mechanics and thermodynamic balance.And make full use of MATLAB calculation software to carry out a detailed study on the predictive ability of the performance evaluation indicators such as exhaust pressure,exhaust temperature and efficiency of the general linear scroll compressor.The analysis shows that when considering the above factors at the same time,the mathematical model established in this paper predicts the performance of the scroll compressor closer to the actual operating results.