Control of Shroud Leakage Loss by Reducing Circumferential Mixing
Control of Shroud Leakage Loss by Reducing Circumferential Mixing
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DOI：
10.1115/1.2750682
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发表时间：
2008-04
影响因子：
1.7
通讯作者：
B. Rosic;J. Denton
中科院分区：
文献类型：
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作者：
B. Rosic;J. Denton
叶冠泄漏流经过叶冠时切向速度变化不大。由于主流流动和泄漏流动之间切向速度的差异而产生的混合在与叶冠泄漏流动相关的总损失中占很大比例。未转动的泄漏流也引起负入射，加剧了下游叶排的二次流。本文介绍了一种将转子叶冠泄漏流转向主叶通道方向以减少气动混合损失的概念的实验结果。本文采用低展弦比叶片的三级空气模型涡轮。在每个转子叶片排下游的转子叶冠出口腔中放置了一系列不同几何形状的静止转动叶片进行了测试。在下游静叶排的气流角和损失显著改善，涡轮制动效率提高了0.4%。
Shroud leakage flow undergoes little change in the tangential velocity as it passes over the shroud. Mixing due to the difference in tangential velocity between the main stream flow and the leakage flow creates a significant proportion of the total loss associated with shroud leakage flow. The unturned leakage flow also causes negative incidence and intensifies the secondary flows in the downstream blade row. This paper describes the experimental results of a concept to turn the rotor shroud leakage flow in the direction of the main blade passage flow in order to reduce the aerodynamic mixing losses. A three-stage air model turbine with low aspect ratio blading was used in this study. A series of different stationary turning vane geometries placed into the rotor shroud exit cavity downstream of each rotor blade row was tested. A significant improvement in flow angle and loss in the downstream stator blade rows was measured together with an increase in turbine brake efficiency of 0.4 %.