水轮发电机组螺栓应力在线测量与分析

On-site measurement and analysis of bolt stress of hydro-generator unit

为了进一步掌握关键部位螺栓的紧固状态,提高设备运行的可靠性,以溪洛渡水电站为实例,中国首次在现场详细测量了水轮发电机组的蜗壳门、锥管门和顶盖位置关键部位螺栓在预紧、充水、运行和甩负荷期间的受力及其变化情况。实测结果表明:顶盖/座环连接螺栓的最大应力为362 MPa,蜗壳进人门螺栓的最大应力为214.8 MPa,受力均在机组设备厂家设计计算应力范围内;在各运行工况下,顶盖/座环连接螺栓、锥管进人门螺栓和蜗壳进人门螺栓的应力幅分别达3.00,4.70 MPa和0.64 MPa,均未超过S-N曲线中规定的应力幅持久疲劳极限,安全裕度较高。该测试成果对研究高强度螺栓的应力应变、疲劳寿命分析,以及对水电机组运行维护工作均具有重要的参考意义。

In order to further grasp the tightening state of bolts on key parts,and improve the operational reliability of equipment,this paper took Xiluodu Hydropower Station as an example.The bolts stress and its changes on key parts of the spiral casing manhole,draft tube manhole and head cover of hydro-generator set were measured on site during the cases of tightening,water filling,operating and load shedding for the first time in China.The measured results showed that the biggest bolt stress of head cover/stay ring connection bolt and the spiral casing manhole reached 362MPa and 214.8MPa respectively,the bolts stresses were all within the range given by the unit manufacturer.Under all kinds of operating conditions,the variation range of bolts stresses of head cover/stay ring connection bolt,draft tube manhole and the spiral casing manhole reached 3.0MPa,4.7MPa and 0.64MPa respectively,which all did not exceed the fatigue limit of stress amplitude specified in S-N curve,so the bolts had higher safety margin.The test results are meaningful to the analysis of stress-strain and fatigue life of bolts,and they are also significant to the operation and maintenance of the hydro-generator units.