针对大截面内保温圆形烟道容易出现变形的特点，以某天然气长输管道压气站余热发电厂已设计的烟道为研究对象，运用有限元法进行整体建模，计算结果显示4 420×5 mm的圆形烟道顶端向下位移166 mm。为满足圆形烟道顶端向下位移量100 mm以内的需求，优化设计烟道，比较了增加加固肋规格、减小加固肋间距和增大外护板厚度3种方案，增大加固肋规格为最优方案，将烟道顶端向下位移值从166 mm降低至96 mm，且仅增加造价2.3万元。

To study the deformation characteristic of large crosssection circular flue with inner insulation，the finite element method is used to model an existing flue designed for the compression station of a long distance natural gas pipeline.The calculation results show that the peak downward displacement of the 4 420×5 mm circular flue is 166 mm.In order to meet the installation requirement of the peak downward displacement being less than 100 mm，the flue design is further optimized，and three kinds of schemes are compared; increasing stiffener size,reducing stiffener spacing and increasing thickness of outer protection plate.The results indicate that increasing stiffener size is the optimum plan，which will reduce the peak downward displacement of the flue from 166 mm to 96 mm,with an additional investment of only 23 000 RMB.

TM621