| With the advantages of high working efficiency and high quality of air supply,twin-screw compressors have been in the dominant position in the compressor market and are widely used in brake,refrigeration and other industrial fields.The ’ 14 th Five-Year Plan ’ requires the modern machinery industry to develop along the direction of high efficiency,high precision and intelligence,which inevitably requires the performance of the twin screw compressor to be improved.The core part of the twin screw compressor is a pair of meshing rotors.The design of the rotor profile is the key to the improvement of the compressor performance.The profile design of twin-screw compressor in China is relatively backward.Not only the profile design method is not suitable for the new generation of profile,but also the traditional pin tooth arc profile is still used as the national standard profile,resulting in the overall performance of domestic compressors still lagging behind that of foreign countries.Focusing on the profile optimization design of the twin-screw compressor rotor,this paper is committed to improving the mainstream profile design method.Through the analysis of the profile performance parameters,a profile with excellent performance is designed.This paper addresses the following issues :(1)Improvement of profile design method.By integrating the design method of compressor rotor profile,the meshing relationship between screw rotors is explored.The meshing position correlation of screw rotor is deduced by means of coordinate transformation,and the objective regularity of this property on rotor meshing is verified.Then the traditional method of line design is improved,which improves the efficiency and feasibility of the derivation of the new generation asymmetric profile with complex tooth curve,and provides theoretical basis for the design of excellent profile.(2)Analysis and optimization of profile performance parameters.The GHH profile of Germany was deduced based on the improved profile design method,and the geometric configuration characteristics of GHH profile were analyzed to establish the mathematical model of GHH screw rotor.The obtained mathematical model is modeled and expressed by threedimensional software to verify whether the continuity of each section of the GHH profile is G1 continuous.The correctness of the derivation of the positive rotor is verified by combining the envelope diagram of the positive rotor profile to the negative rotor profile.Through the comprehensive performance quantitative evaluation system based on fuzzy comprehensive evaluation method and analytic hierarchy process,The performance parameters of GHH profile are optimized and analyzed,and the GHH profile with optimized performance parameters is obtained theoretically.(3)Parametric modeling of screw rotor.The geometric relationship in the mathematical model of GHH profile is transformed into computer language,and the relationship between geometric parameters of GHH profile is explored by combining with the visual expression of easy X drawing plug-in.Combined with the Menu Script,UIStyler and screw rotor parameterization project program,the parameterization and automation of three-dimensional modeling of twin-screw compressor rotor are completed,and the parametric modeling platform of twin-screw compressor rotor is established.(4)Performance simulation and verification analysis of compressor under fluid-thermalsolid coupling.Combined with numerical interpolation technology and multi-field data transfer technology,the method of flow-thermal-solid coupling calculation for twin-screw compressor is established,and the correctness of the method is verified by experiments.Through the numerical simulation of compressor performance before and after profile optimization,the GHH compressor rotor with optimal profile is obtained,and its compression efficiency is increased by3.67 %.Finally,the deformation and stress variation of compressor rotor structure with optimal profile under different working conditions are explored. |
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