1000 MW超超临界汽轮机高压外缸蠕变强度的分析

摘要

以1 000 MW超超临界汽轮机高压外缸为研究对象,通过引入Norton-Bailey材料蠕变本构方程和Cocks-Ashby多轴韧度系数,对汽缸轴对称二维模型的温度场、应力场和CA蠕变等效应变分布进行了计算,找出了结构设计中不合理区域并提出相应的结构改进方案.结果表明:经改进的高压外缸结构设计是合理的;CA蠕变等效应变计算结果均小于推荐考核标准,该1 000 MW超超临界汽轮机高压外缸的高温蠕变应变强度能够满足设计要求.%Taking the high-pressure outer casing of a 1 000 MW ultra supercritical steam turbine as an object of study, and by adopting the Norton-Bailey material creep constitutive equation and Cocks-Ashby multiaxial coefficient, the temperature field, stress field and the CA equivalent creep strain dictribution of the 2D axisymmetric model were calculated, during which the unreasonable structure of original design was found out and impoved with corresponding schemes. Results show that the improved structure of the HP outer casing is reasonable; all the calculated results of CA equivalent creep strain are less than those in the recommended criteria for assessment. The high-temperature creep strain of above mentioned outer casing can meet the design requirements.