介质流速对在线焊接管道极限压力的影响

运用有限元法对不同介质流速下在线焊接时的温度场进行了数值模拟,内部介质流动对焊接温度场的影响通过确定介质与管壁的换热系数来考虑;根据温度计算结果,获得管道的剩余强度因子,进而判定管壁是否烧穿。研究表明,随着流速的增大,焊缝位置处外壁上的峰值温度无明显变化,而内壁上的峰值温度随之下降;在线焊接管道的剩余强度因子及所能承受的极限压力呈上升趋势,且在一定范围内增大明显,故应充分利用该流速变化范围的特点以确定最佳施工条件。

Effect of media flow velocity on limit pressure of pipes during in-service welding

A finite element method is used to conduct a numerical simulation on the temperature field of in-service welding underdifferent media flow velocities. The influence of internal media flow on the welding temperature field is taken into account by determining the media and thermal exchange coefficient of wellbore. The remaining intensity factors of the pipe are obtained to judge if the wellbore is burn through according to the result of calculation. The study indicates that the peak value on the external wall of welding seam is not obviously changed with the increase of flow velocity, while the peak temperature on the internal wall decreases with it. The remaining intensity factors of in-service welding pipes and the limit pressure that they can stand is raised and it is raised greatly in a certain range. Thus the characteristics of flow-velocity changes should be adequately considered for the purpose of establishing the optimal operation conditions.