【作者】 黄祺；

【导师】 李仁年；

【作者基本信息】 兰州理工大学 ， 流体机械及工程， 2012， 硕士

【摘要】 为达到必需的电网调节能力，电力系统中应至少装有总容量5%的抽水蓄能电站，若要达到较好的调节能力，则需要有总容量10%的蓄能装机。“十二五”抽水蓄能规划中有专家认为，抽水蓄能机组设备国产化能力的不足，增加了抽水蓄能电站的投资成本，影响了抽水蓄能电站的发展。可逆式水轮机两种工况点并不重合，故无论是转轮的设计或选型都需要一定的折衷，在确定基本参数的基础上从一个工况开始，使用现有的水力设计方法进行计算，再用另一个工况来校核。本文在此设计理念的基础上设计出了满足性能要求的转轮，并尝试性的研究了可逆机不同工况点的水力性能。转轮设计借鉴低比转速混流式水轮机的叶片设计原理，对一给定参数的可逆机利用水轮机设计理论进行水力设计、三维造型、ICEM网格划分，考虑到高应变率和大曲率过流面等因素的影响采用RNG k-ε模型来封闭求解N-S方程。采用有限元体积法进行离散，离散方程的压力-速度耦合的处理采用压力耦合方程组的半隐式方法(SIMPLEC)算法。利用Fluent软件模拟并反复修正模型，预测了可逆机设计工况下的转轮效率。分析了不同工况点中蜗壳，转轮，尾水管的压力场和速度场的变化，以及内部漩涡的生成原因对其此处压力场、速度场的影响。数值实验结果表明可逆机水轮机工况的最优效率达到91%，水泵工况的最优效率达到82%，反复修正模型还有进一步提升的空间。水泵断电过程中蜗壳内部流动紊乱程度大，二次流，漩涡，流动分离等现象比较严重。这为可逆机水泵工况断电过程中压力突变的定量分析提供了一种新的方法，也为其它工况的计算以及可逆机转轮的水力设计提供了一种新的参考，同时，用CFD技术直观的反映了可逆机不同工况点的水力性能，拟补了经验数据的不足。对于可逆机的转轮设计以及结构优化都有一定的应用价值。更多还原

【Abstract】 To achieve the necessary adjustment ability of the network, at least5%of the totalcapacity of pumped storage power station should be installed in the power system and10%to achieve better adjustment ability. Experts of pumped-storage plan in"12th Five-Year" believed that the inadequate domestic capacity of pumped-storagefacilities had increased the investment costs and influenced the development ofpumped-storage power station.Pump-turbine’s two conditions don’t coincide, so whether the design or selectionof the runner requires some compromise. Based on the determined basic parameters, acondition was calculated using existing hydraulic design methods from the start andchecked by another condition. In this paper, the runner which can meet theperformance requirements was designed on the basis of this concept and attempted tostudy the pump’s hydraulic performance during different operating conditions.The runner design uses the design principle of low specific speed Francisturbine’s blade, then hydraulic design,3D modeling and ICEM meshing were carriedon a pump-turbine with given parameters. Taking into account the factors of highstrain rate and curvature over the stream surface, RNG k-model was used to solveN-S equations. The finite volume method was used to discrete and SIMPLECalgorithm was used to solve pressure-speed coupling equations. By simulating themodel with the software of Fluent and correcting repeatedly, the efficiency ofpump-turbine under design condition was predicted. Besides, the changes of thepressure field and velocity field in volute, runner and draft tube were analyzed duringdifferent operating conditions, then the paper illustrated the influence of internalwhirlpool’s generation causes to the pressure field and velocity field.This design method has provided a new reference for pump-turbine runner’shydraulic design and made up for the lack of empirical data by using CFD technologyto give a direct-viewing reflection of hydraulic performances simultaneously,Numerical experiment results show that the optimal efficiency of turbine’s operatingcondition can reach91%and the optimal efficiency of pump’s can reach82%.Therewill be a further improvement if modify the model repeatedly. There are greatturbulent flow,secondary injection,swirl and flow separation in the volute.This canprovide a new method for the quantitative analysis of sudden change pressure duringthe transition when electricity goes off at Pump working and give some enlightenment for the calculation of other transition process. It’s valuable for pump-turbine runner’sdesign and structural optimization.更多还原