The Optimization Of Vibration And Thrust Of Aeroengine Burner-inner-liner Based On Polynomial Taylor Series Method

Burner-inner-liner(BIL) is an important component of aviation alternator combustion.According to its working principle, optimization design of BIL involves knowledge of multiple discipline. Such as mode analysis and thrust calculation including physics,chemical, burning learn, vibration learn and gas dynamics and so on. All subjects are influenced by each other, so the optimization of BIL can’t use the traditional optimization.The thsis used polynamial Talor expansion optimization method.The thsis used the Finite Element Method( FEM) toolbox of MATLAB to write program of mode analysis and thrust calculation, and based on second-order polynamial Talor expansion method to spread equations of the system. The first-order and second-order sensitivity which appear in system equations adopt lagrange factor function to solve it. This thsis used BFGS’s method to solve optimal value of structure variables iterative and used the golden section method to solve the step length of the optimization.The optimization calculation of BIL is divided into two part. One part is the solution natural frequencies and mode vectors regarded as the response vector and the response values of the system equation basic on mode analysis. At the same time, the BIL by the finite element model is divided into eight element parts. This thsis selected the third,the fourth,the fifth and the sixth Young modulus of element parts as structure variable and used the FEM toolbox of MATLAB to write MATLAB program. The method selected different correction parameters to input program. According to running of program results, the method can calculate accurately the iterative value and choose the optimization method in mode analysis by comparison; The other part is all thrust values and stress values as response value and response vector of the system equation basic on thrust calculation. The method selected nozzle spray out fuel of angle, gas flow, fuel diffusion of maximum of pressure and compressor outlet pressure as structure variable. At the same time,the paper used the FEM toolbox of MATLAB to write program, selected different of correction parameter and correction range to write program. According to the result of running the program, the iterative value of high precision can be solved and on the basis of the number of iterations in the thrust optimization and iteration precision to select the optimization method in thrust design.In conclusion, the study proposes a new method for optimization of BIL and the results of optimization is very close to the target values. The average iteration precision by trust optimization can achieve below 0.5%. The accuracy is particularly high; The accuracy ofthe iteration for mode analysis is 2%, but it is still ideal. At the same time, the Taylor polynomial expansion method theory is verified and showed to be an effective optimization method.Thus it can be used to calculate complicated structure for multi-disciplinary optimization.