基于均匀设计法的涡轮叶栅水滴型前缘修型结构的数值优化研究

为了最大程度地降低端区二次流对涡轮叶栅带来的流动损失，对某典型低压涡轮叶栅引入水滴型前缘修型结构并进行设计参数优化。首先使用控制变量法研究单一设计参数变化对流动控制效果的影响；然后基于均匀设计法，对不同设计参数组合的水滴型前缘修型结构的流动控制效果进行数值模拟，获取控制端区二次流最优的设计方案。结果表明：控制变量优化下的最佳设计方案可以使总压损失降低6.1%；均匀设计优化下的最佳设计方案可以使总压损失降低8.61%。与控制变量法相比，均匀设计法得到的水滴型前缘修型优化结构能够更大程度地降低前缘马蹄涡强度，延后通道涡到达吸力面的位置，减小通道涡对主流的影响范围，进而从流动机理层面证实了均匀设计法优化水滴型前缘修型的可行性。

Numerical Optimization of Teardrop Leading-Edge Fillet by Uniform Design Method in Turbine Cascade

To control the endwall losses caused by the secondary flow in a typical low pressure turbine cascade, a teardrop leading-edge fillet was introduced into it and a series of numerical simulations were carried out to obtain its optimal design parameters. The control variable method was first used to study the influence of single design parameter variation on flow control effect. Then, the uniform design method was used to investigate the flow control effect among different design parameter variations by numerical simulation, and the optimal design for controlling secondary loss was obtained. The results show that: the optimal fillet obtained by control variable method could reduce the total pressure loss by about 6.1%; while, the optimal fillet obtained by uniform design method could further mitigate the total pressure loss by about 2.51%. A detail of flow analysis showed that the optimal fillet obtained by uniform design method could further lower horseshoe vortex intensity, delay development of the passage vortex and reduce its influence range in mainstream as compared to that obtained by control variable, thus proving the feasibility of using uniform design method to optimize teardrop leading-edge fillet from the aspect of flow mechanism.