Aerodynamic Optimization Of A Nonaxisymmetric Endwall Of A Type Of Turbine

With the improvement of the performance requirements of modern Aviation gas engine,the performance of turbine,as one of its core components,also has higher requirements.As an effective means to improve the aerodynamic performance of turbine,non-axisymmetric endwall has been widely used in the current turbine design.Therefore,this paper will carry out the following research work for the non-axisymmetric endwall.Firstly,explore the influence of several typical non-axisymmetric endwall models on the flow field.The protrusion of the non-axisymmetric endwall models on the suction side of the cascade is conducive to weakening the transverse-pressure gradient inside the cascade and reducing the secondary flow loss.The protrusion at the inlet of the cascade delays pressure side of horseshoe vortex to the suction surface and also helps to reduce the secondary flow loss.Secondly,based on Adaptive simulated annealing algorithm(ASA)and Bezier curve method,the "non-axisymmetric endwall profiling system" is established and stator is optimized.The optimization of non-axisymmetric endwall profiling effectively weakens the strength of horseshoe vortex and improves the flow field vortex structure.The results show that the optimized endwall modeling can effectively reduce the flow loss and the total pressure loss from the original 6.769% to 6.430%;Thirdly,according to the position of the horseshoe vortex structure at the leading edge of the cascade,a series of control points is added to optimize the non-axisymmetric endwall.By analyzing the three-dimensional flow field inside the cascade,we can see that the optimized end wall further weakens the strength of horseshoe vortex,optimizes the flow field structure,and reduces the total pressure loss from 6.430% to 6.381%.Fourthly,the non-axisymmetric endwall optimization design of the stage turbine cascade is carried out.Compared with the flow field structure of the stator,the optimization of the flow field structure in the stator blades is poor,but the better outlet flow angle can be obtained,which is conducive to the subsequent work of the rotor blades.Therefore,in the optimization design of the non-axisymmetric endwall shape of the turbine,it is best to carry out the numerical simulation of the whole turbine to avoid the reduction of the efficiency of the subsequent turbine stage,so as to obtain the optimal endwall structure.Fifthly,the influence of the non-axisymmetric endwall modeling on the flow field under different conditions is calculated.Under the condition of different outlet Mach number,the total pressure loss can be reduced by the non axisymmetric end wall,and in a certain range,with the increase of Mach number,the effect of reduction is better.