Effect of Ingress on Turbine Discs
Effect of Ingress on Turbine Discs
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DOI：
10.1115/gt2015-42324
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Geonhwan Cho;C. Sangan;J. Owen;G. Lock
中科院分区：
文献类型：
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作者：
Geonhwan Cho;C. Sangan;J. Owen;G. Lock
热气体通过燃气涡轮机的边缘密封的进入取决于涡轮机环形空间中的主流与密封径向向内的叶轮空间中的主流之间的压差。本文介绍了实验测量，量化的影响，进口的定子和转子盘在叶轮空间密封流加压。红外传感器的开发和校准，以准确地测量在瞬态实验过程中的旋转盘表面的温度历史，导致绝热有效性。根据绝热有效性随密封流速的变化，对四种通用（但具有发动机代表性）单间隙和双间隙密封的性能进行了评估。测量结果确定了所谓的热缓冲效应，其中转子上的边界层保护盘免受进入的影响。结果表明，对于所有测试的边缘密封，转子上的有效性明显高于等效定子有效性。虽然通过边缘密封的进入是不稳定的三维流场的结果，并且压力和密封有效性之间的因果关系是复杂的，但通过相对简单的半经验模型（在另一篇论文中描述），时间平均的实验数据被证明是成功预测的。设计人员特别感兴趣的是，在转子感应到其影响之前，大量侵入物可能会进入轴距。
The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the seal. This paper describes experimental measurements which quantify the effect of ingress on both the stator and rotor discs in a wheel-space pressurised by sealing flow. Infrared sensors were developed and calibrated to accurately measure the temperature history of the rotating disc surface during a transient experiment, leading to an adiabatic effectiveness. The performance of four generic (though engine-representative) single- and double-clearance seals was assessed in terms of the variation of adiabatic effectiveness with sealing flow rate. The measurements identify a so-called thermal buffering effect, where the boundary layer on the rotor protects the disc from the effects of ingress. It was shown that the effectiveness on the rotor was significantly higher than the equivalent stator effectiveness for all rim seals tested. Although the ingress through the rim seal is a consequence of an unsteady, three-dimensional flow field, and the cause-effect relationship between pressure and the sealing effectiveness is complex, the time-averaged experimental data is shown to be successfully predicted by relatively simple semi-empirical models, which are described in a separate paper. Of particular interest to the designer, significant ingress can enter the wheel-space before its effect is sensed by the rotor.Copyright © 2015 by ASME