透平叶栅非轴对称端壁优化目标比较

Comparison of Non-axisymmetric Endwall Optimization Objective for Turbine Cascade

基于双控制曲线和改进的Kriging代理模型建立了非轴对称端壁优化设计系统。以Durham叶栅的端壁优化为例,研究不同优化目标对优化结果的影响。研究表明:在通道涡形成段减小横向压力梯度可以有效抑制通道涡强度,进而减小流动损失;在通道涡发展段减小横向压力梯度有助于降低主流区二次流损失,但端区损失明显增大;增加横向压力梯度有助于减小流向涡量强度;从优化成本考虑,总压损失方案具有最佳的收敛性,与角度相关的优化目标则优化成本较高。

A non-axisymmetric endwall optimization design system was established based on dual control curves and modified Kriging surrogate model.Takingthe endwall optimization of Durham cascadeas an example,the influence of different optimization objectives on the optimization results was studied.The research results show that decreasing the transverse pressure gradient in the passage vortex formation section can effectively suppress the passage vortex intensity and thereby reduce the flow loss.Reducing the transverse pressure gradient in the passage vortex development section is helpful to reduce the secondary flow loss in the mainstream zone,but the end zone loss will increase significantly;Increasing the transverse pressure gradient will help reduce the intensity of the streamwise vorticity.Considering the optimization cost,the total pressure loss scheme has the best convergence,but the optimization objectives related to the angle are more costly.