Influence of Vanes and Blades on Ingress in Axial Rim Seal for Turbine Stages

  • REN Ran ,
  • DU Qiang ,
  • LIU Guang ,
  • ZENG Yanlian ,
  • XIE Lei
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  • 1. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    2. National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine, Beijing 100190, China
    3. School of Aeronautics and Astronautics, University of Chinese Academy of Sciences, Beijing 100190, China

网络出版日期: 2024-04-30

基金资助

The authors wish to acknowledge the financial support of the National Natural Science Foundation Outstanding Youth Foundation (Grant No. 52122603), the National Science and Technology Major Project (J2019-III-0003-0046) and the cloud computing supported by the Beijing Super Cloud Computing Center.

版权

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2024

Influence of Vanes and Blades on Ingress in Axial Rim Seal for Turbine Stages

  • REN Ran ,
  • DU Qiang ,
  • LIU Guang ,
  • ZENG Yanlian ,
  • XIE Lei
Expand
  • 1. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    2. National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine, Beijing 100190, China
    3. School of Aeronautics and Astronautics, University of Chinese Academy of Sciences, Beijing 100190, China

Online published: 2024-04-30

Supported by

The authors wish to acknowledge the financial support of the National Natural Science Foundation Outstanding Youth Foundation (Grant No. 52122603), the National Science and Technology Major Project (J2019-III-0003-0046) and the cloud computing supported by the Beijing Super Cloud Computing Center.

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2024

摘要

高温燃气入侵是指主流高温燃气流入涡轮盘腔的现象。以往的研究发现,主流环空压力分布在燃气入侵中起着重要作用,但由于其复杂性,主流流动与燃气入侵的相互作用机制尚不清楚。本文采用URANS数值方法,考虑Cw=0、Cw=500、Cw=5000等3种密封流量下的入侵机制。通过对时间平均主流环空压力的分析表明,随着密封流量的增加,主流压力值减小,并且密封流量对动叶前缘压力分布的影响远大于导叶尾缘压力分布的影响。对主流压力非定常时空分布的分析表明,当密封流存在时,轮缘处压力存在时空倾斜分布。这种现象主要是由于密封流对环空压力场的强反馈机制造成的。对比主流的压力分布和平均径向速度分布可以看出,入侵主要发生在动叶侧,而动叶侧的压力低于导叶侧。为此分析了密封流量Cw=5000时轮缘处的流动特性,提出了压力诱导入侵和通道涡入侵的两种入侵机制。主流在轮缘处的三维效应和惯性效应导致动叶侧分离涡的产生,分离涡的存在导致沿动叶侧入侵。同时,动叶侧的压力会使流体具有径向向内流动的倾向,这将促进分离涡的形成,导致动叶侧高压区域的入侵更加严重。动叶侧压力场比导叶尾缘压力场在轮缘处的入侵过程中更为显著,这有助于解释动叶的存在对燃气入侵的影响这个不确定的问题。

本文引用格式

REN Ran , DU Qiang , LIU Guang , ZENG Yanlian , XIE Lei . Influence of Vanes and Blades on Ingress in Axial Rim Seal for Turbine Stages[J]. 热科学学报, 2024 , 33(3) : 833 -846 . DOI: 10.1007/s11630-024-1986-0

Abstract

Hot gas ingestion refers to the phenomenon of mainstream hot gas flowing into the space cavity of a turbine wheel. Previous studies have found that mainstream annulus pressure distribution plays an important role in hot gas ingestion, but due to its complexity, the mechanism of the interaction between mainstream flow and hot gas ingestion remains unclear. This paper adopts the URANS method, and three sealing flow rates are considered, named Cw=0, Cw=500, and Cw=5000. The time-averaged annulus pressure distribution shows that an increase in the sealing flow decreases the pressure value, and the effects of the sealing flow on the pressure distribution of the leading edge of the blade are much more influential than that of the trailing edge of the vane. The unsteady pressure time-space distribution in the annulus indicates that a time-space tilted distribution of pressure at the rim exits when the sealing flow exists. This phenomenon is mainly due to the strong feedback mechanism of the sealing flow to the annulus pressure field. A comparison of the pressure and mean radial velocity distribution of the mainstream shows that the ingestion mainly occurs on the blade side, where the pressure is lower than on the vane side. The flow characteristics at the wheel rim are analyzed with a sealing flow rate Cw=5000, and under these conditions, both pressure-induced ingestion and ingestion caused by a passage vortex can be inferred. The three-dimensional and inertial effects of the mainstream at the wheel rim lead to the generation of separation vortices on the blade side, and the presence of separation vortices leads to ingestion along the blade side. At the same time, pressure on the blade side will cause the fluid to have a radial inward flow tendency, which will promote the formation of separation vortices, leading to more serious ingestion in the high-pressure region on the blade side. The blade pressure field can be more significant than the vane trailing pressure field in the rim seal ingestion, and it contributes some explanations to the open question: the effect of blade on ingestion.

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