Study On The Structure And Performance Of A Twin Screw Compressor

Twin screw compressor is a kind of rotary machine which converts low pressure gas into high pressure gas.At present,although the twin screw compressor has made revolutionary progress in the design of rotor profile,there are several urgent problems to be solved in the macroscopic structure design of the main engine and the microscopic characteristics of internal flow field.Second,the research on the performance parameters of the internal flow field of the twin-screw compressor is not comprehensive,and there is a lack of relevant experimental analysis.Thirdly,the effect of clearance leakage on the performance of twin screw compressor has not been systematically and qualitatively described.Aiming at the three major problems existing in the twin screw compressor,based on the basic design principle and fluid dynamics theory of the twin screw compressor,the fluid domain model of the twin screw compressor is established,the exhaust orifice structure is improved,and the influence of clearance leakage on the performance of the twin screw compressor is emphatically analyzed.Firstly,based on the basic theory of rotor profile design,the geometric and thermodynamic characteristics of the rotor end profile of the twin-screw compressor were calculated and analyzed,and a three-dimensional model of the twin-screw compressor was established by combining the rotor profile data.Aiming at the problem that the pressure impact of the exhaust orifice has a large fluctuation and causes aerodynamic noise,the improved design of the exhaust orifice is carried out according to the practical engineering experience.After the improvement,the pressure pulsation ununiformity is reduced by 11.6%and the velocity fluctuation amplitude is reduced by 1.49.Secondly,in view of the characteristics of irregular flow in the internal flow field of the twin-screw compressor,a new method combining Scorg and Pumplinx software is concluded to avoid the phenomenon of negative volume of the dynamic grid and solve the problem of writing complex UDF functions.The variation characteristics of pressure,temperature and flow rate were obtained through simulation calculation,and the variation rules of other performance parameters in the flow field of the twin screw compressor under unsteadyconditions were determined,which avoided the single and one-sided research on the performance parameters of the twin screw compressor at present,and made the research content more systematic.Thirdly,based on the test system established by the production enterprise,according to the test principle,the key parameters such as power,pressure and flow of the twin-screw compressor under the actual working condition were tested.The results show that the difference rate between the axial power simulation data and the experimental data is 2.73%,9.33%,4.92%,and 0.04%,respectively.The numerical simulation method and simulation results are verified to be correct.Finally,on the basis of analyzing the formation mechanism of various kinds of gaps in the twin-screw compressor,seven kinds of fluid models with different sizes of gaps were constructed,and the influence of three leakage paths on the internal flow field of the twin-screw compressor was deeply studied.The results show that the tip clearance leakage has the greatest influence on the performance of screw compressor,followed by the intertooth clearance and the end clearance.