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水轮机顶盖部分螺栓断裂后剩余螺栓的强度分析
引用本文:葛新峰,徐旭,沈明辉,檀林杰,钱巨林,张昌振.水轮机顶盖部分螺栓断裂后剩余螺栓的强度分析[J].排灌机械工程学报,2019,37(7):600-605.
作者姓名:葛新峰  徐旭  沈明辉  檀林杰  钱巨林  张昌振
作者单位:1. 河海大学能源与电气学院, 江苏 南京 211100; 2. 国网河南省电力公司新乡供电公司, 河南 新乡 453002; 3. 国网新源控股有限公司富春江水力发电厂, 浙江 桐庐 311504
摘    要:针对水轮发电机组由于顶盖连接螺栓断裂而导致水淹厂房等严重事故的问题,建立了某电站实际顶盖及螺栓的模型并进行有限元分析.基于Ansys,采用有限单元法求解静力学基本方程,计算得到各种工况下螺栓的应力分布;研究了某混流式水轮机顶盖全部螺栓正常工作时的强度,对部分螺栓断裂后剩余螺栓的强度进行了分析,对比了螺栓在断裂数量为1,2,4,8根以及断裂位置为90°对称分布、邻近分布、180°分布时的应力情况.计算结果表明:部分螺栓断裂后,由于偏载和突变,其余螺栓的最大应力值都会升高;螺栓断裂个数越多,断裂螺栓的分布位置越邻近,则其余螺栓强度越不足.当断裂螺栓数量为4根且处于邻近分布位置时,剩余螺栓的最大应力为744.03 MPa,十分接近螺栓材料的极限容许应力744 MPa;当断裂螺栓处于邻近分布位置且数量达到8根时,剩余螺栓的最大应力达776.21 MPa,增幅达19.69%,已远远超过材料极限容许应力,威胁电站安全运行.

关 键 词:水轮机  顶盖螺栓  断裂分布  应力  强度分析  
收稿时间:2018-11-06

Strength analysis of remaining bolts as several connection bolts of hydro-turbine head cover in failure
GE Xinfeng,XU Xu,SHEN Minghui,TAN Linjie,QIAN Julin,ZHANG Changzheng.Strength analysis of remaining bolts as several connection bolts of hydro-turbine head cover in failure[J].Journal of Drainage and Irrigation Machinery Engineering,2019,37(7):600-605.
Authors:GE Xinfeng  XU Xu  SHEN Minghui  TAN Linjie  QIAN Julin  ZHANG Changzheng
Institution:1. College of Energy and Electrical Engineering, Hohai University, Nanjing, Jiangsu 211100, China; 2. Xinxiang Power Supply Company, State Grid Henan Electric Power Co., Xinxiang, Henan 453002, China; 3. Fuchunjiang Hydropower Plant, State Grid Xinyuan Co. Ltd., Tonglu, Zhejiang 311504, China
Abstract:Aiming at severe accidents such as flooding hydropower plant caused by broken connection bolts of head cover in hydro-generator units, the geometrical and mechanical models of head cover and connection bolts of a hydro-turbine in a hydropower plant were established and analyzed by using finite element method. Based on the finite element method in Ansys, the static element force equilibrium equations were solved numerically, and the stress distribution in the bolts were determined under va-rious working conditions. Firstly, a normal case was established, i.e. the bolt strength was analyzed when all the bolts engaged properly under runaway condition. Then, a few bolt failure cases were taken into consideration to determine the strength of the remaining bolts, namely, the cases where there are 1, 2, 4 and 8 bolts failed which can be distributed 90?symmetrically, side by side and 180?apart. Results show that the maximum stress level in the remaining bolts increases after several bolts are broken due to uneven distribution of the bolts along the circumferential direction. Specially, the more the bolts are broken and the closer the broken bolts are distributed, the less the strength of the remaining bolts is. When the number of failed bolts is 4 and they are distributed side by side, the maximum stress level of the remaining bolts is as high as 744.03 MPa, which is very close to the bolt allowable stress 744 MPa. When the number of failed bolts is 8 and they are positioned side by side, the maximum stress is increased by 19.69% and arrives at 776.21 MPa, which is far beyond the allowable stress, clearly the safe operation of the hydropower plant will be under threat.
Keywords:turbine  cover bolts  fracture distribution  stress  strength analysis  
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