融合多源数据挖掘信息的非轴对称端壁/叶身联合成型设计空间知识挖掘

Exploration of the Design Space for Non-Axisymmetric Endwall/Blade Through Integration of Multi-Source Data Mining Techniques

为厘清联合成型设计空间各造型方法对涡轮叶栅性能提升的贡献,将基于总变差分析的全局敏感性分析方法与平行坐标系及直方图、散点图等可视化技术相结合,提出了将多源数据挖掘信息进行融合的设计空间知识挖掘框架,并利用该框架对某小展弦比叶栅端壁/叶身联合成型设计空间进行知识挖掘。结果表明:叶栅气动损失增减对基元型线微调十分敏感;非轴对称端壁所带来的损失减少量与型线微调接近,但设计空间内不同非轴对称端壁样本性能波动较小,导致其重要性被全局敏感性分析方法低估;虽然单独采用弯叶片难以整体降低小展弦比叶栅损失,但将弯、型线微调和非轴对称端壁造型相结合可获得“1+1+1>3”的性能增益;在端壁/叶身联合成型设计空间内,将基元型线朝着后加载方向微调,并采用喉部附近下凹较深的非轴对称端壁造型及反弯叶片设计,可获得气动损失较小的叶栅设计。研究结果明晰了端壁/叶身联合成型设计空间优化解特征,可为类似小展弦比叶栅设计优化提供借鉴。

To enhance understanding of the role different cascade profiling techniques play in improving turbine cascade performance within the combined design space,a knowledge mining framework is proposed.This framework integrates data mining information through the analysis of variance-based global sensitivity analysis method and employs visualization techniques like parallel axis,histogram and scatterplot.By using this framework,knowledge mining of the non-axisymmetric endwall/blade combined parameterization design space of a low aspect ratio cascade is conducted.It reveals that the aerodynamic loss of the cascade is highly influenced by the section profiling.The reduction in loss achieved through the implementation of a non-axisymmetric endwall is comparable to that of section profiling.However,it is observed that the performance variations among different samples of non-axisymmetric endwall are relatively small,leading to the underestimation of its significance by the global sensitivity analysis method.Furthermore,it is found that utilizing only a bending curved blade is unlikely to yield a reduction in cascade loss.However,by combining blade bending,section profiling and non-axisymmetric endwall,it is possible to achieve a performance gain that exceeds the sum of the individual contributions(“1+1+1>3”).Within the combined design space of non-axisymmetric endwall/blade parameterization,it is observed that a cascade with low aerodynamic loss can be achieved by adjusting the section profile towards an after-loading style and incorporating a non-axisymmetric endwall with deep concave near the throat and negatively bending blade as well.In conclusion,this research has successfully elucidated the characteristics of optimized solutions within the end-wall/blade joint forming design,offering reference for the design optimization of similar low aspect ratio cascades.The above findings have effectively clarified the characteristics of the optimized solutions within the endwall/blade combined design space,offering guidance for the design optimization of similar low aspect ratio cascades.