河流穿越高压输气管道悬空长度的动态演变过程及临界状态的数值方法研究

Study of Numerical Method on Critical Suspended Length and Critical Failure State of High-pressure Gas Pipeline Crossing Riverbed

针对河流对穿越高压输气管道支撑边界的冲刷导致悬空长度变化的动态演变过程,利用ANSYS Multiphys-ics软件建立河床-管道-水流3维有限元整体模型。运用顺序耦合法实现了穿越高压输气管道由于水流冲刷引起悬空长度不断变化条件下流体与固体结构间双向耦合的动力学仿真。针对西气东输的实际高压输气管道,获得了在不同悬空长度和水流速度下管道的动态应力应变场及热点应力,基于强度准则确定了不同壁厚管道在不同流速下的临界悬空长度。提出的河流穿越高压输气管道悬空长度的动态演变过程及临界状态的数值方法,可为河流穿越输气管道的安全监测及风险评价提供理论支撑。

The whole 3 D finite element model of riverbed-pipeline-flow was established to studied the dynamic evolution process of sus- pended length change resulting from river flushing of support of high pressure gas pipeline by using ANSYS Muhiphysics. The sequen- tial coupling method which achieved a two-way coupling between fluid and solid was used to analyze the variation law of the maximum effective stress and displacement of pipeline under different suspended lengths. The dynamic stress-strain field and hot spot stress of pipeline with different thicknesses under different flowing velocities were evaluated. Based on strength failure criterion, the critical sus- pended lengths of pipelines of West-East Gas Pipeline with different thicknesses under different flowing velocities were estimated. The dynamic floating simulation and failure state determine method of river crossing pipeline can provide theoretical support for the safety monitoring and risk assessment of river crossing gas pipeline.