Impact of Turbine Center Frame Wakes on Downstream Rows in Heavy-Duty Low-Pressure Turbine

IF 3.1 3区工程技术 Q3 ENGINEERING, MECHANICAL

Journal of Turbomachinery-Transactions of the Asme Pub Date : 2019-01-01 DOI:10.1115/1.4045348

S. Biagiotti, J. Bellucci, M. Marconcini, A. Arnone, Gino Baldi, M. Ignesti, V. Michelassi, Libero Tapinassi

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引用次数: 1

Abstract

In this work, the effects of turbine center frame (TCF) wakes on the aeromechanical behavior of the downstream low-pressure turbine (LPT) blades are numerically investigated and compared with the experimental data. A small industrial gas turbine has been selected as a test case, composed of a TCF followed by the two low-pressure stages and a turbine rear frame (TRF) before the exhaust plenum. Full annulus unsteady computations of the whole low-pressure module have been performed. Two operating conditions, full (100%) and partial (50%) load, have been investigated with the aim of highlighting the impact of TCF wakes convection and diffusion through the downstream rows. Attention was paid to the harmonic content of rotors’ blades. The results show a slower decay of the wakes through the downstream rows in off-design conditions compared with the design point. The analysis of the rotors’ frequency spectrum reveals that moving from design to off-design conditions, the effect of the TCF does not change significantly. The harmonic contribution of all turbine components has been extracted, highlighting the effect of statoric parts on the last LPT blade. The TCF harmonic content remains the most relevant from an aeromechanic point of view as per experimental evidence, and it is considered for an forced response analysis (FRA) on the last LPT blade itself. Finally, aerodynamic and aeromechanic predictions have been compared with the experimental data to validate the numerical approach. Some general design solutions aimed at mitigating the TCF wakes impact are discussed.

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重型低压汽轮机中心架尾迹对下游排流的影响

本文对涡轮中心架尾迹对下游低压涡轮叶片气动性能的影响进行了数值研究，并与实验数据进行了比较。选择了一台小型工业燃气轮机作为试验用例，该燃气轮机由一个TCF和两个低压级以及排气室前的涡轮后框架(TRF)组成。对整个低压模块进行了全环空非定常计算。研究了两种工况，满负荷(100%)和部分负荷(50%)，目的是突出TCF尾迹在下游排中的对流和扩散的影响。对转子叶片的谐波含量进行了研究。结果表明，与设计点相比，在非设计条件下尾迹通过下游排的衰减速度较慢。对转子频谱的分析表明，从设计状态到非设计状态，TCF的影响没有明显变化。提取了所有涡轮部件的谐波贡献，突出了静态部件对最后LPT叶片的影响。从气动力学的角度来看，根据实验证据，TCF谐波含量仍然是最相关的，并且它被考虑用于最后LPT叶片本身的强迫响应分析(FRA)。最后，将气动和气动力学预测与实验数据进行了比较，以验证数值方法的有效性。讨论了一些旨在减轻TCF尾迹影响的一般设计方案。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Turbomachinery-Transactions of the Asme 工程技术-工程：机械

CiteScore

4.70

自引率

11.80%

发文量

168

审稿时长

9 months

期刊介绍： The Journal of Turbomachinery publishes archival-quality, peer-reviewed technical papers that advance the state-of-the-art of turbomachinery technology related to gas turbine engines. The broad scope of the subject matter includes the fluid dynamics, heat transfer, and aeromechanics technology associated with the design, analysis, modeling, testing, and performance of turbomachinery. Emphasis is placed on gas-path technologies associated with axial compressors, centrifugal compressors, and turbines. Topics: Aerodynamic design, analysis, and test of compressor and turbine blading; Compressor stall, surge, and operability issues; Heat transfer phenomena and film cooling design, analysis, and testing in turbines; Aeromechanical instabilities; Computational fluid dynamics (CFD) applied to turbomachinery, boundary layer development, measurement techniques, and cavity and leaking flows.