| Modern airliners adopt high bypass ratio turbofan engine.Compressor and large fan are the core components of turbofan engine,of which the performance improvement is vital for the improvement of engine performance.On the other hand,the improvement of compressor/fan blade performance depends on good blade design.The theoretical basis of blade design is the regular change of aerodynamic performance parameters caused by the change of blade geometric modeling.For example,the change of blade shape at various radial position will change the spanwise load distribution,which can have different effects on the performance of compressor/fan blade.Therefore,as the bridge of blade shape and performance,the spanwise load distribution form is of great significance to the study on the performance of the compressor/fan by mastering which its influence law can improve blade performance in a directional way.Through literature research,it has been found the difference of load between optimized blade and original blade at different blade heights in optimization of aerodynamic performance of compressor/fan at home and abroad.However,there are still some shortcomings—the spanwise load distribution is not directly related to the main performance parameters of the compressor/fan and there is a lack of experimental study on the influence of spanwise load distribution.In view of the above mentioned shortcomings,the basic mature compressor/fan optimization design technology is used to optimize the design of actual blade in this paper.By comparison between original blade and optimized blade obtained by optimization,this paper analyzes the law of the influence on main performance parameters including efficiency,total pressure rise and the stable operation range.On the other hand,taking the single-stage axial flow compressor as the research object,the influence of incoming load distribution on compressor performance is investigated by experimental method.The specific research work is mainly as following:(1)Based on the Kriging Agent Model,a set of aerodynamic optimization design method for the performance of compressor and high bypass ratio fan blade is constructed.This method integrates parametric modeling,grid generation,CFD simulation and post-processing combination optimization technology.Taking profiles on various cross sections of blades as the optimization object,this method sets blade installation angle rotating and maximum thickness position moving as parameters for reconstruction of blade shape,selects related performance parameters to be studied as object function and carries out optimization evaluation on main performance parameters of compressor/ fan blades.(2)Based on the numerical optimization platform and blade design technology,it studies the influence of load distribution on performance parameters,including efficiency and total pressure rise.For the main performance parameters of compressor including efficiency and total pressure rise,the optimization design is carried out by applying the above optimization methods.After several iterations,feasible areas in design space is successfully searched so that the objective function is improved rapidly and the optimal design is found.Taking efficiency and total pressure rise as objective functions,the obtained optimized blades have improved efficiency and total pressure rise by 3.07% and 14.8% respectively,and have greatly improved the corresponding performance indexes in the whole working condition range.Through the analysis of the radial distribution of the outlet parameters of the optimized blade and the details of the flow field,it investigates effect law of spanwise load distribution on efficiency,total pressure rise and other performance parameters.(3)Based on the numerical optimization platform and blade design,the influence of blade power distribution on the stable operation range of large fan is studied in this paper.The optimization method is used to optimize the stable operation range,which is one of the most significant performance parameters of the large fan.The optimization process effectively broadens the stable operating range of the fan blades by 10.1%,among which the performance is greatly improved.Through the analysis of the radial distribution of the outlet parameters of the optimized blade and the details of the flow field,it studies the effect law of spanwise load distribution on performance parameters such as stable operation range of large fan.(4)Taking single-stage low speed axial flow compressor as the research object,the effect of different flow load distribution on the performance of the compressor is investigated.Under certain geometric constraints,three basic types of pressure profiles are designed,corresponding to incoming flow forms of uniform inflow,the speed increases along the radial direction and speed decreases along radial direction.According to preliminary design3 D modeling is carried out and its changing effect on incoming load distribution is verified by CFD simulation.Then three kinds of pressure profile devices are obtained by manufacture.The pressure profile is fitted to the upstream position of the compressor rotor and the performance test of the compressor is carried out under the above three flow forms.According to the experimental results,the stable operation range and total pressure rise in characteristic curve have changed under the influence of incoming radial load.The influence of incoming radial load on compressor performance is researched through analysis of the variation of the aerodynamic parameters in radial distribution. |
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