An Advanced Single-Stage Turbine Facility for Investigating Nonaxisymmetric Contoured Endwalls in the Presence of Purge Flow
An Advanced Single-Stage Turbine Facility for Investigating Nonaxisymmetric Contoured Endwalls in the Presence of Purge Flow
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DOI：
10.1115/1.4045087
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发表时间：
2019-06
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通讯作者：
Robin E. Jones;Oliver J Pountney;Bjorn Cleton;Liam E. Wood;B. Schreiner;A. J. C. Figueiredo;James A. Scobie;D. Cleaver;G. Lock;C. Sangan
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作者：
Robin E. Jones;Oliver J Pountney;Bjorn Cleton;Liam E. Wood;B. Schreiner;A. J. C. Figueiredo;James A. Scobie;D. Cleaver;G. Lock;C. Sangan
在现代燃气轮机中，端壁轮廓(EWC)被用来修正叶片下游的静压场，并最大限度地减少叶片通道中二次流结构的发展。来自上游轮缘密封的吹扫流动(或出口)干扰主流流动，增加了转子中产生的损失。尽管如此，EWC的设计通常没有考虑主流与出口的相互作用。当考虑吹扫空气时，EWC提供的性能收益可以减少，或者在限制范围内消除。此外，EWC会导致整个轮缘密封圈的密封效率降低。因此，工业界正在寻求一种综合设计方法，包括轮缘密封、密封间隙轮廓和转子端壁上的EWC。本文介绍了一种新的单级轴流涡轮装置的设计和初步结果，该装置是为了研究出口-主流流动相互作用的基本流体动力学而开发的。据作者所知，这是世界上唯一能够研究空腔流、轮缘密封和EWC之间相互影响的试验装置。还提出了未来研究中使用体积测速(VV)和平面激光诱导荧光(PLIF)的光学测量能力的设计。流体动力定标钻井平台在与这些技术相适应的良好压力和温度下运行，并且是模块化的。该设施可以方便地互换EWC(集成到转子衬里)、叶片圆角和轮缘密封几何形状。本文所介绍的测量包括：定子壁面和轮空心部气体浓度、效率和涡流的测量；喷嘴导叶(NGV)三个不同展向位置的压力分布；定子平台上四个轴向位置NGV下游的节向静压分布。
In modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimize the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream–egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile, and EWC on the rotor endwall. This paper presents the design of and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress–mainstream flow interactions. To the authors' knowledge, this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals, and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry (VV) and planar laser-induced fluorescence (PLIF), is also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seal geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes (NGV) at three different spanwise locations; pitchwise static pressure distributions downstream of the NGV at four axial locations on the stator platform.