Analysis of Head Losses in a Turbine Draft Tube by Means of 3D Unsteady Simulations
Analysis of Head Losses in a Turbine Draft Tube by Means of 3D Unsteady Simulations
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DOI：
10.1007/s10494-016-9767-9
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
S. Wilhelm;G. Balarac;O. Métais;C. Ségoufin
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文献类型：
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作者：
S. Wilhelm;G. Balarac;O. Métais;C. Ségoufin
本文提出了灯泡式水轮机尾水管中的非定常 RANS (URANS) 模拟和大涡模拟 (LES)，旨在了解和定位该水轮机部件的水头损失。考虑涡轮机的三个工作点。将数值结果与实验速度测量结果进行比较以进行验证。通过对尾水管中能量平衡的详细分析，确定了导致尾水管水头损失的物理和流体动力学现象。水头损失是由于平均动能转移到湍流和动能的粘性耗散造成的。这主要发生在中央涡流结构和尾水管壁附近。研究发现水头损失预测取决于模拟中使用的湍流模型，尤其是在 URANS 模拟中。通过这种分析，可以了解三个工作点之间水头损失的演变。
In this paper, Unsteady RANS (URANS) simulations and Large Eddy Simulations (LES) in the draft tube of a bulb turbine are presented with the objective to understand and locate the head losses in this turbine component. Three operating points of the turbine are considered. Numerical results are compared with experimental velocity measurements for validation. Thanks to a detailed analysis of the energy balance in the draft tube, the physical and hydrodynamic phenomena responsible for head losses in the draft tube are identified. Head losses are due to transfer of mean kinetic energy to the turbulent flow and viscous dissipation of kinetic energy. This occurs mainly in the central vortex structure and next to the walls in the draft tube. Head losses prediction is found to be dependent on the turbulence model used in the simulations, especially in URANS simulations. Using this analysis, the evolution of head losses between the three operating points is understood.