汽轮机隔板高温蠕变寿命评估方法的研究

An Assessment Method of High Temperature Creep Life of Steam Turbine Diaphragm

针对现役引进型机组高温蠕变现象难于正确评估的情况,提出了根据机组历次大修记录的变形数据和有限元计算相结合的方法得到材料蠕变参数.采用该方法对某电厂600 MW机组T11级隔板的高温蠕变变形问题进行了分析研究,并应用商用软件对隔板在继续运行中的变形和应力情况作出了预测和评估.结果表明:隔板最大应力产生的位置在隔板外环叶片的出汽侧,靠近中分面边缘叶根、叶片的出汽边处,其值为160 MPa.按每年连续运行8 000 h计算,隔板的使用寿命约为30年,与制造商提供的设计寿命一致,得出了机组在一个大修期内不必立即更换隔板的结论,节约了维修费用,为汽轮机或燃气轮机高温部件的蠕变寿命的评估提供了一种实用方法.

Aiming at the difficult to assess high temperature creep in the imported unit properly, a method was put forward, which is to get material creep parameters by history deformation data of the diaphragm recorded in all previous overhaul, combined with the finite element analysis. By the method, the creep deformation under high temperature conditions was analyzed for Tll diaphragm of the 600 MW turbine, the prediction and assess for the deformation and stress of the diaphragm in posterior operation were done by commercial software. Results show that the highest stress of the diaphragm appeared at the blade＇s exit side of the shroud, at the blade root and trailing edge near the adge of horizontal split with its value of 160 MPa. If the unit runs 8000 hours every year, the hours that the diaphragm may be continuously used in service is about 30 years. It is same to the manufacturer＇s design data. So the diaphragm may not be replaced during a period of overhaul, and the maintenance costs are saved. It offers a practical method to assess the creep life of high temperature part of steam turbine and gas turbine.