Fluid flow analysis of drooping phenomena in pump mode for a given guide vane setting of a pump-turbine model
Fluid flow analysis of drooping phenomena in pump mode for a given guide vane setting of a pump-turbine model
复制标题
DOI：
10.1631/jzus.a1500087
复制
发表时间：
2015-11-01
影响因子：
3.2
通讯作者：
Liu, Zhan-sheng
中科院分区：
文献类型：
--
作者：
Li, De-you;Gong, Ru-zhi;Liu, Zhan-sheng
具有驼峰区的水泵模式下，水泵水轮机的能量排放特性对机组的运行稳定性具有重要意义。为了研究导叶开度为32 mm时的流动特性，采用切应力输运(SST)k-omega湍流模型，通过求解雷诺平均N-S方程，对导叶开度为32 mm的导叶进行了三维定常数值模拟。在对计算流体力学(CFD)结果进行实验验证的基础上，选择部分负荷(0.45Phi(BEP))、下垂区负荷(0.65Phi(BEP))、接近最佳效率点(BEP)(0.90Phi(BEP))、BEP(1.00Phi(BEP))和过载(1.24Phi(BEP))区域来分析流道内流体性质变化的方式和原因。通过对水流角度和水力损失的分析，得出了水流分离的原因和不同负荷点的水流空间特征。结果表明，这五个工作点的前缘和后缘的流动角分布不同。然后，基于欧拉理论分析了产生下垂的原因。结果表明，下垂行为既有入射/偏离效应，又有摩擦损失。此外，水力损失分析表明，转轮损失对下垂的影响更大。
The energy-discharge characteristics of pump-turbines in pump mode with a hump region are significantly important for operating stability. To investigate the flow characteristics, 3D steady numerical simulations are conducted for a given guide vane opening of 32 mm by solving Reynolds-averaged Navier-Stokes (RANS) equations using the shear-stress transport (SST) k-omega turbulence model. Based on the validation of computational fluid dynamics (CFD) results using experimental benchmarks, the part-load (0.45 phi (BEP)), drooping zone load (0.65 phi (BEP)), near best efficiency point (BEP) (0.90 phi (BEP)), BEP (1.00 phi (BEP)), and overload (1.24 phi (BEP)) regions are chosen to analyze how and why the fluid properties change in the runner. The causes of flow separation and spatial characteristics of flow at different load points are obtained through the analysis of flow angle and hydraulic losses. The results show that flow angle at the leading and trailing edge from the crown to the band distributes differently among these five operating points. Then, the reasons for drooping are investigated based on the Euler theory. It is found that drooping behavior comes from both the incidence/deviation effect and frictional losses. In addition, the runner losses are more consequential to drooping as shown by hydraulic loss analysis.