某超临界汽轮机高压内缸紧固螺栓的热-机耦合应力分析  

Thermal-mechanical coupling stress analysis of fastening bolts in high pressure inner cylinder of a supercritical steam turbine

作　　者：汪志刚 陈腊梅 黄一君 江峰[1] 楼玉民 叶笃毅[3] WANG Zhi-gang;CHEN La-mei;Huang Yi-jun;JIANG Feng;LOU Yu-min;YE Du-yi(Hangzhou Huadian Banshan Power Generation Co.Ltd,Hangzhou 310015,China;Zhejiang Zheneng Technology Research Institute Co.,Ltd.,Hangzhou 311121,China;College of Energy Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]杭州华电半山发电有限公司,浙江杭州310015 [2]浙江浙能技术研究院有限公司,浙江杭州311121 [3]浙江大学能源工程学院,浙江杭州310027

出　　处：《能源工程》2021年第5期14-19,共6页Energy Engineering

摘　　要：针对某电厂660 MW超临界汽轮机高压内缸紧固螺栓断裂原因分析需求,以汽缸-螺栓系统为研究对象,应用弹塑性有限元法,并引入子模型分析技术,分别构建了以螺栓光杆模型为基础的汽缸-螺栓整体有限元模型以及考虑螺纹细节的螺栓有限元子模型。以整体模型为基础,结合汽轮机冷启动过程热力参数,模拟了高压内缸及其关键紧固螺栓的温度与耦合应力随启动过程的变化,并确定出螺栓最大耦合应力时刻。进一步采用有限元子模型模拟了该时刻下紧固螺栓的局部热-机耦合应力场,并确定出螺纹牙根部的等效应力分布。通过与螺栓材料的屈服强度进行比较,表明该紧固螺栓与下缸体啮合第一扣螺纹等效耦合应力已超过材料的屈服极限,因此,在实际服役中,循环塑性应变与低周疲劳损伤可能成为紧固螺栓断裂的原因之一。In this paper both the global-FE model of a cylinder-bolt system where the bolt was simplified as the rod model and the sub-FE model of the fastening bolt containing screw threads were established using elastic-plastic finite element method and by introducing the son model analysis technology in order to investigate the fracture reasons of the fastening bolt in the high pressure cylinder of a 660 MW supercritical steam turbine.Based on the global-FE model and combined with the steam turbine thermal parameters during a cold start process,the transient coupling stress field and temperature field of the high pressure inner cylinder and its key fastening boll were simulated,and the lime at which the maximum coupling stress occurred in the bolt was determined.Furthermore,the local thermal-mechanical coupling stress field of the fastening bolt as well as the distribution of the equivalent stress at the screw thread root in the fastening bolt was simulated by using the sub-FE model.It was found that the maximum equivalent stress of the fastening bolt exceeded the yield strength of the bolt material.Therefore,cyclic plastic strain and low cycle fatigue damage may be one of the causes of fastening bolt fracture in practical service.

关 键 词：紧固螺栓 高压缸 热-机耦合应力 子模型 有限元法 

分 类 号：TK263[动力工程及工程热物理—动力机械及工程]