多相混输管道90°弯管冲蚀破坏应力分析

Analysis of erosion fracture stress of 90° elbow in multi-phase mixed transmission pipeline

建立了热流固耦合控制方程,借助Fluent和Ansys软件对多相介质流经管道弯头进行了流场和应力、应变分析,探讨了不同入口速度、管径、弯径比、流体温度对弯头冲蚀失效的影响。研究表明:弯管内壁面剪切应力的大小和分布受多重因素的影响;最大壁面切向应力分布在弯头两颊或下游外拱壁面处,且受流体温度的影响;热应变最大位置出现在弯头两颊和内拱壁面。弯管两颊和下游外拱壁面冲蚀破坏最为严重,为失效高发区。适当降低流速、增大管径和弯径比、升高流体温度均可以有效缓解管道的冲蚀破坏。研究结论可为进一步研究多相混输管道冲刷腐蚀机理提供理论依据。

The fluid-solid-heat coupling equation established is used to analyze the flow field,stress and strain of multiphase medium flowing throughout the pipeline elbow via the Fluent and Ansys software,and further research on the influence of different inlet velocity,pipe diameter,R/D-ratio and liquid temperature on elbow erosion failure is carried out. As the study shown,the magnitude and distribution of shear force acted on the inner surface of elbow are affected by many factors the distribution of the biggest tangential stress is in the two sides or the downstream of outer buttress surface and is affected by liquid temperature. The largest heat strain is in the two sides and inner buttress surface of elbow,in which the most severe erosion is found,that is,it is a highly possible failure part. Appropriately reducing flow speed,enlarging pipe diameter,R/D-ratio and enhancing liquid temperature may efficiently minimize erosion fracture stress to the pipeline. The research outcome can be a theoretical foundation for the further study on erosion mechanisms of multiphase mixed transmission pipeline.