Effect of honeycomb seals on loss characteristics in shroud cavities of an axial turbine
Effect of honeycomb seals on loss characteristics in shroud cavities of an axial turbine
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DOI：
10.3901/cjme.2013.01.069
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发表时间：
2013-02
影响因子：
4.2
通讯作者：
Jie Gao;Q. Zheng;Z. Wang
中科院分区：
文献类型：
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作者：
Jie Gao;Q. Zheng;Z. Wang
由于围带泄漏或叶尖间隙流引起的效率损失占总效率损失的很大一部分。识别泄漏损失特性对于优化泄漏控制是非常重要的。目前，尽管蜂窝密封件的使用非常广泛，但公开文献中关于蜂窝密封件对轴流式涡轮机围带腔中损失特性的影响的信息很少。因此，转子迷宫密封泄漏流与蜂窝饰面和没有之间的相互作用进行了研究，提供的损失特性的混合过程中的泄漏流进入主流。分析了蜂窝密封对围带空腔流动的影响以及与主流的相互作用。还介绍了对细微的围带空腔出口几何形状的影响的附加研究。研究结果表明，与固体迷宫密封相比，蜂窝密封影响了叶顶泄漏流，降低了混合损失。泄漏流与主流的相互作用显著改变了端壁区域的流场。研究结果揭示了蜂窝密封对围带腔损失特性的影响，以及围带腔出口几何形状的细微变化对围带腔损失特性的影响，为蜂窝密封的优化设计提供了参考。
The loss in efficiency due to shroud leakage or tip clearance flow accounts for a substantial part of the overall losses in turbomachinery. It is important to identify the leakage loss characteristics in order to optimize turbomachinery. At present, little information is available in the open literature concerning the effect of honeycomb seals on the loss characteristics in shroud cavities of an axial turbine, despite of the widespread use of the honeycomb seals. Therefore, interaction between rotor labyrinth seal leakage flow with and without honeycomb facings and main flow is investigated to provide the loss characteristics of the mixing process of the re-entering leakage flow into the main flow. The effects of honeycomb seals on the flow in shroud cavities and interaction with the main flow are analyzed. An additional study on the impact of subtle shroud cavity exit geometry is also presented. The investigation results indicate that the honeycomb seal affects the over tip leakage flow and reduces mixing losses when compared to the solid labyrinth seal. The leakage flow interactions with the main flow have considerably changed the flow fields in the endwall regions. The proposed research reveals the effects of honeycomb seals on the loss characteristics in shroud cavities and the impact of subtle shroud cavity exit geometry, and it is helpful for the design optimization of turbomachinery.