Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation
Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation
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DOI：
10.1016/j.energy.2021.122988
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发表时间：
2021-12
期刊：
影响因子：
9
通讯作者：
M. E. Nakhchi;S. W. Naung;M. Rahmati
中科院分区：
文献类型：
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作者：
M. E. Nakhchi;S. W. Naung;M. Rahmati
叶片振动引起的颤振不稳定性是轴流压气机叶栅中的一个主要问题。本文研究了叶片振动对现代燃气轮机压气机气动性能和湍流特性的影响。基于谱hp元方法，对不同振动频率（0 <f< 8.28 Hz）下压气机叶片表面的流动不稳定性、压力脉动和旋涡生成进行了高精度的直接数值模拟。本研究的主要新奇是在DNS分析中考虑了压气机叶片的气动弹性振动。新提出的方法，使复杂的结构流体相互作用的详细分析，这是不能得到使用其他方法，如RANS模型。模拟结果表明，叶片振动对叶片吸力面涡的产生和层流分离泡有很大的影响。在90%翼展处，非定常压力分布幅值较大，相位角在100° ~ 350°之间。在振动叶栅尾流区中心观察到强烈的脉动。这些波动是由叶片振动引起的气流扰动激活的。此外，与静止叶片相比，振荡叶片的尾迹区会产生强烈的压力波动。与Xsep/C = 0.314的固定叶片相比，k = 0.4（Xsep/C = 0.288）的振动叶片吸力面上的分离点出现时间快8.28%。
Flutter instability because of the blade vibrations is a major problem in axial compressor cascades. This paper investigates the effects of blade oscillations on aerodynamic performance and turbulent flow characteristics of modern gas-turbine compressors. Highly accurate direct numerical simulations (DNS) are performed based on the spectral-hp element method to predict the flow instabilities, pressure fluctuations and vortex generation on the surface of the compressor blades by considering all complex physical parameters at different vibration frequencies (0 <f< 8.28 Hz). The main novelty of this study is to consider the aeroelastic vibrations of the compressor blades in DNS analysis. The novel proposed method enables the detailed analysis of complex structure fluid interactions, which cannot be obtained using other methods such as RANS models. The simulations revealed that the blade oscillations have a huge impact on the vortex generation and laminar separation bubble on the suction side of the blade. Moreover, the amplitude of unsteady pressure distribution is greater at 90% span, with the phage angle deviating between 100° and 350°. Strong fluctuations are observed at the centre of the wake region of the vibrating blade cascade. These fluctuations are activated by the flow disturbances resulting from the blade oscillation. Moreover, intense pressure fluctuations happen in the wake region of the oscillating compressor blade compared with the stationary one. The separating point occurred 8.28% sooner on the suction surface of the vibrating blade with k = 0.4 (Xsep/C = 0.288) compared to the stationary blade with Xsep/C = 0.314.