Experimental Measurements of Ingestion Through Turbine Rim Seals: Part 3—Single and Double Seals
Experimental Measurements of Ingestion Through Turbine Rim Seals: Part 3—Single and Double Seals
复制标题
通过涡轮机边缘密封件吸入的实验测量：第 3 部分 — 单密封件和双密封件
DOI：
10.1115/gt2012-68493
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发表时间：
2012
影响因子：
1.5
通讯作者：
G. Lock
中科院分区：
文献类型：
--
作者：
C. Sangan;James A. Scobie;J. Owen;Oliver J Pountney;M. Wilson;G. Lock
本文描述了一个研究装置的实验结果，该装置对进入轴流式涡轮机级叶轮空间的热气进行了实验建模。测量边缘密封区域和轴距内的CO2气体浓度，以评估一般（虽然发动机代表性）单密封和双密封的性能，即浓度有效性随密封流速的变化。涡轮机环形空间内的压力变化（控制外部诱导进气）通过叶片下游的稳态压力测量获得。使用双密封的好处得到了证明：吸入的气体主要局限于内密封径向向外的外部叶轮空间;在内密封径向向内的内部叶轮空间内，有效性明显更高。提出了单密封和双密封性能的分级标准，并指出任何双密封的性能极限是内部密封暴露于旋转引起的进入的极限。虽然进入是非稳态三维流场的结果，压力和密封有效性之间的因果关系很复杂，实验数据可以通过理论模型推导出的简单有效性方程成功地计算出来。数据表明，对于类似的涡轮级速度三角形，可以使用两个经验参数来关联有效性。原则上，这些相关性可以外推到在发动机代表性条件下运行的几何形状相似的涡轮机。
This paper describes experimental results from a research facility which experimentally models hot gas ingress into the wheel-space of an axial turbine stage. Measurements of CO2 gas concentration in the rim-seal region and inside the wheel-space are used to assess the performance of generic (though engine-representative) single and double seals in terms of the variation of concentration effectiveness with sealing flow rate. The variation of pressure in the turbine annulus, which governs externally-induced ingress, was obtained from steady pressure measurements downstream of the vanes.The benefit of using double seals is demonstrated: the ingested gas is shown to be predominately confined to the outer wheel-space radially outward of the inner seal; in the inner wheel-space, radially inward of the inner seal, the effectiveness is shown to be significantly higher. Criteria for ranking the performance of single and double seals are proposed, and the performance limit for any double seal is shown to be one in which the inner seal is exposed to rotationally-induced ingress.Although the ingress is a consequence of an unsteady, three-dimensional flow field and the cause-effect relationship between pressure and the sealing effectiveness is complex, the experimental data is shown to be successfully calculated by simple effectiveness equations developed from a theoretical model. The data illustrate that, for similar turbine-stage velocity triangles, the effectiveness can be correlated using two empirical parameters. In principle, these correlations could be extrapolated to a geometrically-similar turbine operating at engine-representative conditions.Copyright © 2012 by ASME