高压管汇活动弯头接触特性分析

Contact Characteristics of Active Elbow in High-Pressure Manifold

为探究高压管汇活动弯头活动节在现场油气田使用过程中滚道易出现点蚀现象的原因,选取某厂型号为φ130.2 mm-105 MPa(5 1/8 in-15 000 psi)的大通径活动弯头作为研究对象,采用有限元分析软件研究不同滚道轴向间距、径向间距、滚道半径对滚道接触应力的影响规律。研究结果表明:随着活动弯头滚道轴向间距的增大,最大接触应力呈现增长趋势;随着径向间距的增大,最大接触应力总体呈现上升趋势;随着滚道半径的增大,最大接触应力呈现先降低后增大的趋势,在滚道半径为9.66 mm时达到最低。针对活动弯头活动节第一滚道相较于其余滚道接触应力较大的现象,通过对弯头结构分块解析,发现弯头偏载原因主要为弯头不同部位的结构刚度存在差异,且管壁内压是导致弯头偏载的载荷来源。指出管壁内压直接作用于外接头,导致外接头滚道最大接触应力比内接头大。研究结果可为活动弯头活动节进一步优化设计提供参考。

In order to investigate the raceway pitting corrosion of the active elbow in high-pressure manifold in oil and gas fields,a large-diameter active elbow of Model 130.2 mm-105 MPa (5 1/8 in-15 000 psi) was taken as an example to investigate the influences of different raceway axial spacing,radial spacing and raceway radius on the raceway contact stress by using the finite element analysis software.The results show that,as the raceway axial spacing of active elbow increases,the maximum contact stress increases;as the raceway radial spacing increases,the maximum contact stress rises generally;as the raceway radius increases,the maximum contact stress decreases first and then increases,which reaches the minimum value when the raceway radius is 9.66 mm.In view of the phenomenon that the contact stress of the first raceway of the active elbow is higher than that of other raceways,the elbow structure was divided into 6 regions for analysis.It is found that the eccentric load of the elbow is mainly resulted from the difference of structural rigidity in different parts of the elbow,and the internal pressure of pipe wall is the source of the eccentric load.The internal pressure of pipe wall directly acts on the outer joint;as a result,the maximum contact stress of the raceway of the outer joint is larger than that of the inner joint.The results provide references for the optimization design of the active elbow.