摘要
对于混流式水轮机,活动导叶与固定导叶以及转轮的相对位置直接影响导水机构和转轮内部流动,对水轮机安全、稳定、高效运行起到重要作用。采用商业软件ANSYS CFX 16. 0对某电站水轮机模型机全流道进行三维数值模拟计算,提出了5种活动导叶分布圆直径方案,分析不同方案下水轮机的外部能量特性与内部流场,寻找活动导叶安放的最佳位置。结果表明:适当增大活动导叶分布圆直径,可以有效改善叶片吸力面的低压区,降低活动导叶流域内水流的最大速度,改善转轮进口水流角,同时减小导水机构与转轮的水力损失。小流量工况下,D_0/D_1增大0. 031,水轮机效率提高了5. 28个百分点;设计工况与大流量工况下,活动导叶分布圆的变化对水轮机效率的影响相对于小流量工况较小,最高效率与最低效率的差值分别为0. 17%与0. 48%。因此,在一定范围内改变活动导叶的分布圆直径具有可实施性,对水轮机的优化设计有一定参考价值。
For a Francis turbine, the movable guide vane is mainly used to regulate the flow rate and circulation, the relative positions of guide vane, stay vane and the runner directly affect the internal flow of water guiding mechanism and runner, which play an important role in the safe, stable and efficient operation of the turbine. The commercial software ANSYS CFX 16.0 was used to calculate the three-dimensional steady flow in the full flow channel of a hydraulic turbine model machine. Five guide vane distribution circle diameter schemes were proposed to be analyzed, aiming at obtaining the energy characteristics and internal flow fields of the turbine under different schemes. Then the best position of the active vane placement was determined, and the results showed that by appropriately increasing the circular diameter of the guide vane distribution, the low-pressure area at the suction surface of the blade could be improved, the maximum flow velocity around guide vanes could also be reduced, the flow angle at the inlet of the runner was more reasonable, and the hydraulic losses of the guide mechanism and the runner were decreased, and the turbine operating efficiency was improved. At low flow rates, D 0 / D 1 (guide vane distribution circle diameter/runner diameter) was increased by 0.031, and the turbine corresponding efficiency was increased by 5.28 percentage points, at designing flow rate or high ones, the influence of change of guide vane distribution on the turbine efficiency was smaller than that at low flow rates. Compared with the different circle diameter schemes of guide vane, the difference between the highest efficiency and the lowest efficiency were 0.17% under the design condition and 0.48% at the high flow one, respectively. Therefore, changing the distribution circle diameter of the guide vane within a certain range had the engineering practicability in the capacity-increasing projects of the water-power station units, which can be applied in optimizing the Francis turbine.
作者
吴子娟
梁武科
董玮
陈帝伊
WU Zijuan;LIANG Wuke;DONG Wei;CHEN Diyi(Institute of Water Resources and Hydro-electric Engineering,Xi’an University of Technology,Xi an 710048,China;College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2019年第5期140-147,共8页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金优秀青年科学基金项目(51622906)
关键词
水轮机
活动导叶
分布圆直径
数值模拟
hydro-turbine
guide vane
distribution circle diameter
numerical simulation
