三峡左岸电厂6F机组小开度工况异常振动动态数值解析  

Dynamic numerical investigation on the abnormal oscillation of the 6F unit of the Three Gorges left bank plant under small opening condition

作　　者：彭玉成[1] 张克危[1] 占梁梁[2] 张双全[1] 

机构地区：[1]华中科技大学能源学院,武汉430074 [2]华中科技大学水电与数字化工程学院,武汉430074

出　　处：《水力发电学报》2008年第6期157-162,共6页Journal of Hydroelectric Engineering

摘　　要：三峡左岸电厂6F机组在过速试验的关机过程中,出现了强烈的小开度工况下的异常振动现象。该现象是过去未曾关注过的。借助STAR-CD解算器和分离涡模拟的方法,对包括蜗壳、固定导叶、活动导叶、转轮和尾水管在内的计算域进行动态的数值解析。计算结果显示,在所计算的小开度工况下,活动导叶出口处的流动沿活动导叶高度方向是不均匀的,活动导叶下半部分区域靠近底环处存在漩涡,导致水流从活动导叶的上半部分流出到转轮室。傅立叶分析表明,在此漩涡区域附近,流体单元的速度脉动和压力脉动的主频均为1.359Hz,正好与真机试验测得的异常振动频率一致。进一步的分析表明,漩涡区域的1.359Hz的脉动是计算域内其他位置出现的相同频率的脉动的源头。An abnormal oscillation phenomenon happened during the over-speed test on the 6 # hydro-generator unit of the Three Gorges left bank hydropower plant. This phenomenon has never been concerned and discussed. Using STAR-CD casing, commercial code, together with the detached eddy simulation method, the computational domains consisting of the spiral caseng, the stay vane, the guide vane, the runner and the draft are dynamically resolved. The results show that the flow is uneven along the guide vane height direction under the small-opening condition. Vortex motion exists in the lower half of the guide vanes and the most fluid flows into the runner blade chamber from the upper half of the guide vanes. The Fourieranalysis indicates that the main frequency of the velocity and the pressure of the fluid near the vortex region is 1. 359Hz, which is coincident with the abnormal oscillation frequency of the over-speed test. The further studies show that the pressure fluctuation of the vortex region is the source which affects other regions such as the spiral casing and runner, et al.

关 键 词：水力机械 动态CFD分析 小开度振动 分离涡模拟 

分 类 号：TK730.1[交通运输工程—轮机工程]