内外压热应力影响下西气东输二线长输管道变形的有限元分析  

The finite element analysis and calculation of pipeline stress and strain under the effect of heat stress and internal or external pressure in the West-to-East China Gas Pipeline Ⅱ

作　　者：李茂华[1] 石磊彬[1] 钟威[1] 高剑锋[1] 

机构地区：[1]中国石油天然气管道工程有限公司

出　　处：《天然气工业》2013年第8期119-124,共6页Natural Gas Industry

基　　金：西气东输二线科研项目(编号:CQE200700508)

摘　　要：管道在输气过程中由于热胀冷缩效应会产生热应力,造成管道伸缩挤压而产生弯曲变形。为此,根据西气东输二线的现场实际资料,建立了进出压气站管道热应力有限元模型,应用Ansys有限元分析软件,计算分析了管道在内外压及输气温度作用下的管道应力及应变的分布规律:①温度变化对管道应力影响较大,管道应力随输气压力的增加而增加,管道外壁压力对管道应力及变形影响较小;②管道内外壁温差对管道应力影响较大,管道两端有固定墩约束时,应力随温度的增加而增大,管道一端有固定墩约束时,应力随温差的增加而逐渐减小;③管道内外壁温差较小、管道两端有固定墩约束时,应力随输气温度的增加而明显增大;④管道内外壁温差较小、管道一端有固定墩约束时,应力随输气温度的增加变化不大。因此,管道进出站场时,应在适当的距离增加弯头,使热应力有效分散到弯管处,并增加固定墩保护,以保证管道及站场设备安全及正常生产。Expansion and contraction in the process of gas transmission will produce heat stress in line pipes, which will result in pipe’s bending deformation. In view of this, based on the real data from the WesttoEast China Gas Pipeline Ⅱ, a finite element model of thermal stress and structural mechanics was first established for the pipes going into and out of a compressor station. Then, the ANSYS software was adopted to calculate and analyze the stress and strain of such line pipes under the function of internal or external pressure as well as the pipeline gas temperature. The following findings were concluded. a. The temperature variation has a greater impact on pipe stress. Pipe stress increases with the increase of pipeline gas pressure, but the outer wall force has very little effect on pipe stress and strain. b. The temperature difference between the outer and inner walls of a pipe also has a bigger impact on pipe stress. c. With the anchor block fixed on one end of a pipe, pipe stress decreases gradually with the rising pipeline gas temperature but keeps almost unchanged when such a temperature difference is very small. d. With the anchor blocks fixed on both ends of a pipe, pipe stress increases with the rising pipeline gas temperature and even significantly surges when such a temperature difference is very small. On this basis, it is recommended that elbows should be added within a proper distance in the line pipes into and out of a compressor station, with which the thermal stress will be distributed to those bends, thus, in addition to the anchored blocks, the safety and normal production of pipes and equipments at stations will be guaranteed.

关 键 词：西气东输二线 管道应力 有限元 热应力 弹性模量 抗压强度 热膨胀系数 导热系数 固定墩 

分 类 号：TE973[石油与天然气工程—石油机械设备]