Impeller Reverse Design Of Centrifugal Compressor And Its Internal Flow Characteristics Study

With energy crisis aggravating and environmental problems such as fog and haze frequently arising,countries put forward higher requirement on automobile energy conservation and emissions reduction.Pressurization technology can improve engine dynamic performance and fuel economy,reduce emissions at the same time,which has become an indispensable key technology in modern automobile industry.Centrifugal supercharger with its fast response characteristics attracts more and more people's attention.Centrifugal compressor is one of the key parts of centrifugal supercharger,and the performance of compressor direct determines supercharging effect.Gas flow inside compressor is very complex.With gas flowing inside flow passage,several losses exist such as shock,wake and leakage.So the centrifugal compressor internal flow field distribution and the influence of main parameters on its performance is of great significance.In this paper,a centrifugal compressor used for supercharger is chosen to complete 3-D modeling through reverse design and conduct internal flow characteristics study.The main research involves:Based on reverse design method,choose reasonable point cloud sampling device and method to obtain high quality impeller point cloud data,discuss the pretreatment process of point cloud data,reconstruction method of the impeller curve and surface and precision evaluation of the reconstruction model.Finally the model compressor impeller is reconstruct.Numerical analysis software is used to do compressor impeller aerodynamic analysis,and the impeller flow characteristic curve is obtained and the overall performance of the impeller and flow analysis of gas inside the compressor impeller passage are analyzed.Shock wave,leakage,and wake losses produced inside the flow passage of impeller are explored.Through analysis,shock wave was found at blade leading edge near the blade tip and diffused along the flow direction inside flow passage;clearance leakage existed on blade tip;the impeller outlet has obvious low speed wake area where low-energy fluid gathered.All these flow losses affect the working efficiency of the compressor.Four major influence factors(tip clearance,inlet wheel cover diameter,inlet hub diameter and outlet bending angle)are studied.By changing the parameter values to explore their effect on the performance of the compressor.Detailed analysis of various influence factors on inlet,outlet and internal flow condition of compressor impeller has been finished.From all different combinations of the above four factors,select the representative groups for numerical analysis.Using statistical method to deal with the results,this paper discusses the influence degree of four factors on the aerodynamic performance of compressor impeller,works out a better improvement scheme,and do analysis on the aerodynamic characteristics of the improved scheme,verify the validity of the improved compressor impeller.Finally the flow condition inside the improved compressor is enhanced.Flow losses such as shock wave,leakage and wakes are under control,and overall efficiency has increased by 0.96%.