Simulation Analysis And Research On The Internal Flow Field Of Twin-screw Compressor

The screw compressor has a simple structure,reliable mechanical performance,good power balance,small pulsation,long life,energy saving and environmental protection,easy maintenance and operation,and is widely used in chemical,mining,machinery,construction,metallurgy,refrigeration and other fields.Improve,is gradually replacing other types of compressors.According to the statistics of screw compressors,the sales volume of screw compressors accounts for more than 80% of the market share of all positive displacement compressors.And,of all positive displacement compressors,50% are screw compressors.It can be seen that the application of screw compressors will continue to expand,especially oil-free screw air compressors and other various screw process compressors will be developed faster.However,the current development countries for high-performance twin-screw compressors are mainly concentrated in the United States,Britain,Germany,and France.The twin screw compressors produced in China still have a big gap with international products in terms of performance,life and reliability.Therefore,it is necessary to conduct a simulation analysis of the internal flow field of the twin screw compressor.This method is an important research approach to improve the performance of the compressor.In this paper,based on the theory of computational fluid dynamics(CFD),the internal flow field of the 5/7 tooth twin screw air compressor is studied.The main work done is:(1)Analyze and discuss the research background and significance of this subject,study the current status and development trend of twin screw compressor technology at home and abroad in detail,and determine the research content and methods through the preliminary work.(2)According to the working principle of the twin screw compressor,the design method,geometric characteristics and thermal performance calculation of the rotor profile of the twin screw compressor will be discussed in depth.Focus on the geometric performance of the twin screw compressor(including leakage triangle,inter-tooth area,inter-tooth volume,area utilization coefficient,torsion angle coefficient,internal volume ratio and contact line,etc.).(3)Establish a three-dimensional model of the twin-screw compressor,and use a commercial meshing software and simulation software to mesh the Yin and Yang rotor basinsand the inlet and outlet basins of the twin-screw compressor.By comparing the internal flow field distribution of the 3/5-tooth screw compressor with relevant experimental data,the error between the simulated volume flow value and the experimental data is between 3.350% and5.008%;the error between the outlet temperature simulation data and the experimental data is1.282.%～2.127%.It is concluded that the simulation effect is better and has reference.(4)Using the above simulation method,the main research object of this paper is 5/7 twin screw compressor.The research results show that the outlet temperature and outlet pressure of the twin screw compressor increase with the increase of speed and pressure ratio.In the ten simulated working conditions,the maximum temperature of the outlet of the twin screw compressor can reach 437.80 K and the maximum pressure can reach 1321395pa;the mass flow of the outlet increases with the increase of the speed,but with the increase of the pressure ratio Decrease.In the simulated ten working conditions,the maximum mass flow can reach 209.5589 kg / min.