凹槽叶顶参数化椭圆孔冷却布局多变量气热优化研究

Multivariate Aero-thermal Optimization for Parameterized Oval Hole Cooling Layout on a Squealer Blade Tip

为进一步提升凹槽叶顶椭圆孔及参数化组合偏转角的应用前景,建立了降维Kriging代理模型指导多目标遗传算法更新种群的优化算法流程,设计了帕累托前沿局部搜索策略,以最大化气膜冷却效率、最小化泄漏流量为设计目标,耦合稳态RANS数值计算方法,开展了多变量凹槽叶顶冷却布局优化与分析。研究结果显示,凹槽叶顶椭圆孔耦合大角度的正轴向偏转角与负径向偏转角能显著增强气膜贴壁性、大幅提升气膜覆盖范围,同时引导射流向凹槽下游堆积,提升凹槽尾缘处的局部阻塞效应。适当调整部分冷却孔径向偏转角度可以在保持大范围的气膜扩散幅度及均匀的冷却效率分布的前提下,促进泄漏流量进一步降低。优化结构相比圆形孔参考结构的气膜冷却效率提升了436.3%,泄漏流量相对降低了2.141%。

In order to further broaden the application prospect of the oval hole and parameterization combined inclination method on the squealer tip,the optimized multi-objective generic algorithm of multi-objective genetic algorithm guided by the reduced-dimensional Kriging surrogate model for updating the offspring population was established,and the local search strategy for the Pareto frontier was designed.With the design objectives of maximizing the cooling effectiveness and minimizing the leakage flow rate,coupled with the steady-state RANS numerical method,the multivariable optimization and analysis of the cooling layout on the squealer tip were carried out.The results show that the coupling of intense positive axial inclination and negative radial inclination of the oval hole significantly enhances the wall attachment performance and the film coverage,and the accumulation of jets downstream of the cavity assists to increase the local blocking effect at the rear of the cavity.Appropriate adjustment of the radial inclination of several cooling holes promotes further reduction of the leakage flow rate,while maintaining uniformity of cooling effectiveness and a wide range of film diffusion.The optimized structure improves the film cooling effectiveness by 436.3%and the leakage flow rate is relatively reduced by 2.141%compared to the round hole.