Design Optimization of Profiled Endwall with Consideration of Cooling and Rim Seal Flow Effects
Design Optimization of Profiled Endwall with Consideration of Cooling and Rim Seal Flow Effects
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考虑冷却和边缘密封流动效应的异型端壁设计优化
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
H. Luo
中科院分区：
文献类型：
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作者：
H. Tang;Shuaiqiang Liu;H. Luo
异型端壁是改善涡轮机气动性能的有效手段。在过去的十年中，这种方法在许多发动机上得到了广泛的研究。当考虑自动设计优化时，大多数研究通常基于简化模拟模型的假设，而不考虑冷却和边缘密封流动。然而，许多研究人员发现，当应用高保真几何配置时，优化过程所获得的一些好处会丢失。在此之前，优化过程已经通过集成内部几何操纵器、商业三维CFD流求解器和优化驱动程序IsightTM来实现。该优化程序已执行[12]，用于设计涡轮机叶栅和一级半轴向涡轮机的异形端壁。涡轮机性能的改进已经实现。当异形端壁应用于高压涡轮机时，应解决冷却和边缘密封流动的问题。本文研究了轮缘密封流动和冷却对两级高压涡轮机流场的影响。采用不同的优化模型分别考虑边缘流动和冷却的影响，对一号转子端壁进行了三次优化设计。结果表明，边缘密封流动对流场有显著的影响。冷却能极大地改变汽轮机的运行工况，但对涡轮机内的二次流影响不大。详细分析了异形端壁对涡轮机内流场和凹腔的影响。当将边缘流动考虑到优化中时，实现了二次流的显著减少和相应的性能的提高。传统的异型端壁优化机理是减小横通道比降，这对二次流强度有很大影响。然而，考虑到边缘密封流动，异形端壁主要通过控制边缘密封流动的路径来改善涡轮机性能。然后，考虑边缘密封流动的优化程序也被应用于定子二的异型端壁设计。© 2016 ASME
Profiled endwall is an effective method to improve aerodynamic performance of turbine. This approach has been widely studied in the past decade on many engines. When automatic design optimisation is considered, most of the researches are usually based on the assumption of a simplified simulation model without considering cooling and rim seal flows. However, many researchers find out that some of the benefits achieved by optimization procedure are lost when applying the high-fidelity geometry configuration. Previously, an optimization procedure has been implemented by integrating the in-house geometry manipulator, a commercial three-dimensional CFD flow solver and the optimization driver, IsightTM. This optimization procedure has been executed [12] to design profiled endwalls for a turbine cascade and a one-and-half stage axial turbine. Improvements of the turbine performance have been achieved. As the profiled endwall is applied to a high pressure turbine, the problems of cooling and rim seal flows should be addressed. In this work, the effects of rim seal flow and cooling on the flow field of two-stage high pressure turbine have been presented. Three optimization runs are performed to design the profiled endwall of Rotor-One with different optimization model to consider the effects of rim flow and cooling separately. It is found that the rim seal flow has a significant impact on the flow field. The cooling is able to change the operation condition greatly, but barely affects the secondary flow in the turbine. The influences of the profiled endwalls on the flow field in turbine and cavities have been analyzed in detail. A significant reduction of secondary flows and corresponding increase of performance are achieved when taking account of the rim flows into the optimization. The traditional optimization mechanism of profiled endwall is to reduce the cross passage gradient, which has great influence on the strength of the secondary flow. However, with considering the rim seal flows, the profiled endwall improves the turbine performance mainly by controlling the path of rim seal flow. Then the optimization procedure with consideration of rim seal flow has also been applied to the design of the profiled endwall for Stator Two.© 2016 ASME