Analysis And Optimization Of The Geometric Uncertainty Of Transonic Axial Compressor Blade

Compressor blade has the characteristics of complex three-dimensional changes and thin blade shape,and the limitations of processing and manufacturing process make the geometric uncertainty of compressor blade inevitably exists,which has a negative impact on the aerodynamic performance.In order to explore the influence of compressor blade geometric uncertainty on the actual aerodynamic performance,grasp the flow machnism and reduce the adverse effect of the geometric uncertainty,this dissertation focous on the following aspects of the subject.Firstly,through qualitative,quantitative local and global sensitivity analysis of the transonic rotor with geometric uncertainty,the characteristics of the analysis method in application are mastered.Through the comparison of analysis results and time consumption,the application of global sensitivity analysis is of great scientific significance.Through global sensitivity analysis,it was found that the geometric uncertainty parameters with the greatest contribution to efficiency and pressure ratio were the trailing edge wedge angle at 75% blade height,and the contribution values were 24.7%and 30.5%,respectively.Moreover,there were many geometric uncertainty parameters with low contribution,which provided a basis for the follow-up sensitivity reduction research.The aerodynamic parameters are more sensitive to the geometric uncertainty parameters of the upper part of the blade than the lower part of the blade,so the geometric uncertainty distribution of the upper part of the blade height should be strictly controlled during manufacturing.Through the analysis of the internal flow field,the main reason for the aerodynamic performance decline is the increase of the loss at the trailing edge.The increase of aerodynamic performance is determined by the change of suction front edge and the position and size of shock wave.Secondly,blade bowing technology was introduced into the prototype rotor blade,and the ranking of the contribution of key geometric uncertainties to aerodynamic parameters was analyzed from the bow height and the bow angle.Through the analysis of the internal flow field,the mechanism of the application of curved blade technology in the study of sensitivity reduction was explored.The results show that the sensitivity of aerodynamic parameters to key geometric uncertainties can be reduced,but the aerodynamic performance is reduced.The inverse lean scheme with bow angle of 15° and bow height of 40% blade height has the best desensitization effect,and its aerodynamic performance decreases the most.Lower leaves high section uncertainty parameters on the properties of pneumatic contribution value was increased,but the upper leaves high cross section of the uncertainty of geometric parameters on the aerodynamic parameters contribution value is still greater than the lower part leaf the contribution value of the section,high upper lobe distribution of uncertainty at the high still is strictly grasp the focus of the processing and manufacturing process;Reverse technology of curved blade is through the straight to the wall on both ends of the radial force to change the low-energy fluid distribution,pneumatic parameter in the second half part of leaf area high amplitude is greater than in the upper part of regional change,the half part of the uncertainty of the geometric parameters of contribution value increases,the upper parts of the contribution value of geometrical uncertainty parameter is reduced;By changing the inlet angle of attack,change the size and location of the shock wave,and close to the front part of the load change is bigger than the extent of change as a trailing edge part,near the blade leading edge of blade geometry value is greater than the contribution of the uncertainty parameters change near the trailing edge of the blade geometry parameter uncertainty contribution value change,eventually making the contribution of curved blade sort,great changes have taken place the purpose of reducing the sensitivity of prototype aerodynamic parameters to the key geometric uncertainty parameters of the blade is realized.Finally,the multi-objective optimization method of proxy model coupled genetic algorithm was adopted to robustness optimize the mean and variance of aerodynamic parameters of the reverse lean scheme with bow angle of 15° and bow height of 40%blade height,and the Pareto leading edge solution set is finally obtained.By comparing and analyzing the optimization results,it is finally shown that,mainly by changing the leading edge radius,the static pressure transition of the suction surface near the leading edge is smoother and the flow is smoother,and the load of this part is also increased automatically,so as to improve the aerodynamic performance of the blade and ensure its robustness.