Overtip Shock Wave Structure and Its Impact on Turbine Blade Tip Heat Transfer
Overtip Shock Wave Structure and Its Impact on Turbine Blade Tip Heat Transfer
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DOI：
10.1115/1.4002949
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发表时间：
2011-10
影响因子：
1.7
通讯作者：
Qiang Zhang;D. O’Dowd;Li He;Andrew P. S. Wheeler;P. Ligrani;B. Cheong
中科院分区：
文献类型：
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作者：
Qiang Zhang;D. O’Dowd;Li He;Andrew P. S. Wheeler;P. Ligrani;B. Cheong
本文采用实验和计算相结合的方法，研究了高压涡轮叶片尖端的跨音速流型及其对换热的影响。在牛津高速线性叶栅研究设施内，采用瞬时红外热成像技术，在单级高压涡轮叶片(、弦)的条件下获得了空间分辨的换热数据。计算流体动力学(CFD)预测是使用劳斯莱斯Hydra/PADRAM套件进行的。CFD解算器能够捕捉大部分空间热流密度的变化，并给出了预测结果，与实验数据吻合较好。结果表明，叶尖大部分为超音速流动，峰值马赫数可达1.8。与开放文献中的其他低速数据不同，涡轮叶片尖端换热受叶尖缝隙内激波结构的影响很大。斜冲击波在尖端压力侧边缘附近被激发，然后在外壳和尖端之间被多次反射。叶尖缝隙内的超音速流动一般由缝隙出口附近的法向激波终止。测量和计算的换热空间分布都显示出非常明显的条纹，作为多激波结构的特征。总体而言，叶尖的超音速部分的换热明显低于前缘附近，在那里，叶尖缝隙内的流动保持在亚音速。
In this paper, the transonic flow pattern and its influence on heat transfer on a high-pressure turbine blade tip are investigated using experimental and computational methods. Spatially resolved heat transfer data are obtained at conditions representative of a single-stage high-pressure turbine blade (,,chord) using the transient infrared thermography technique within the Oxford high speed linear cascade research facility. Computational fluid dynamics (CFD) predictions are conducted using the Rolls-Royce HYDRA/PADRAM suite. The CFD solver is able to capture most of the spatial heat flux variations and gives prediction results, which compare well with the experimental data. The results show that the majority of the blade tip experiences a supersonic flow with peak Mach number reaching 1.8. Unlike other low-speed data in the open literature, the turbine blade tip heat transfer is greatly influenced by the shock wave structure inside the tip gap. Oblique shock waves are initiated near the pressure-side edge of the tip, prior to being reflected multiple times between the casing and the tip. Supersonic flow within the tip gap is generally terminated by a normal shock near the exit of the gap. Both measured and calculated heat transfer spatial distributions illustrate very clear stripes as the signature of the multiple shock structure. Overall, the supersonic part of tip experiences noticeably lower heat transfer than that near the leading-edge where the flow inside the tip gap remains subsonic.