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为进一步提升非轴对称端壁造型技术在改善高压涡轮导向器叶栅通道内流场结构的能力,借助数值优化手段对一高压涡轮导向器上、下端壁进行了基于Bezier曲线的非轴对称端壁曲面造型优化,为揭示非轴对称端壁在改善高压涡轮导向器流场方面的流动机理,借助三维空间流线对比分析了优化前后导向器通道内端区的流场结构。优化结果表明:非轴对称端壁有效地降低了导向器出口的流动损失,总压损失降低了9.93%,而出口流量最大增幅不到0.13%,同时,出口气流角分布也更加均匀;流场分析表明:高压涡轮导向器中的通道涡主要是由端壁附面层内的低能流体组成,其强度主要是由端壁附面层横向迁移强度及马蹄涡压力面分支强度所决定;优化后得到的非轴对称端壁通过改变端区局部静压场分布,实现了对端壁附面层迁移的控制,从而达到改善端区流场结构、降低流动损失的目的。
In order to further enhance the capability of non-axisymmetric end wall modeling technology to improve the flow field structure in the cascade of high-pressure turbine guide vanes, a Bezier curve-based non-axisymmetric end In order to reveal the flow mechanism of the non-axisymmetric endwall in improving the flow field of high-pressure turbine guide, the flow field structure of the guideway channel in the front and back of the optimized channel is analyzed and contrasted with three-dimensional flowline. The optimization results show that the non-axisymmetric endwall effectively reduces the flow loss at the outlet of the guide, the total pressure loss is reduced by 9.93%, while the maximum increase of the outlet flow rate is less than 0.13%, meanwhile, the angular distribution of the outlet airflow is more uniform. The analysis shows that the passage eddy in the high-pressure turbine guide is mainly composed of low-energy fluid in the endwall cladding, and its strength is mainly determined by the lateral migration strength of the endwall cladding and the branch strength of the pressure surface of the horseshoe vortex. After optimization The obtained non-axisymmetric endwall can be controlled by changing the local hydrostatic field distribution in the end area to improve the flow field structure in the endwall and reduce the flow loss.