含砂油气环状流弯管侵蚀的数值模拟

Numerical Simulation on Bent Pipe Erosion by Sand Laden Oil and Gas Annular Flow

为了探究油气管道内含砂环状流的砂粒侵蚀规律,以90°弯管为研究对象,利用软件STAR CCM+进行数值模拟,选用VOF模型计算油气连续相流场、拉格朗日多相模型计算离散相颗粒的运动、DNV模型计算颗粒对弯管的侵蚀。研究结果表明:流场在弯头区域出现二次流,油膜不再是规则的环状分布,外侧油膜厚度大于内侧,油气两相发生掺混;管道侵蚀与颗粒运动息息相关,受颗粒在壁面处的质量通量、碰撞速度以及碰撞角度等因素影响;颗粒集中碰撞于弯头外侧壁面,发生侵蚀的区域也集中于此,侵蚀形貌呈圆形,最大侵蚀率出现在弯头41.5°外壁顶部,此处的颗粒质量通量较高、碰撞速度大、与碰撞角度相关的函数值接近极大值;管壁油膜能减缓颗粒运动速度,对管道侵蚀起保护作用。研究结果对油气田开发工程的安全运营有一定指导作用。

In order to explore the sand erosion law of sand laden annular flow in oil and gas pipelines,by means of taking a normal bend as the research object,the STAR CCM+software was used to conduct numerical simulation,the VOF model was used to calculate the flow field of oil and gas continuous phase,the Lagrange multiphase model was used to calculate the movement of discrete phase particles,and the DNV model was used to calculate the erosion of particles on the bent pipe.The research results show that secondary flow occurs in the elbow region,the oil film is no longer a regular annular distribution,the oil film thickness on the outer side is greater than that on the inner side,and the oil and gas phases are mixed;pipeline erosion is closely related to particle movement,and is affected by the factors such as mass flux,impact speed and impact angle of particles on the wall;the impact of particles concentrates on the outer wall of the elbow,the erosion area is also concentrated here,the erosion morphology is round,the maximum erosion rate occurs at the top of the outer wall of the elbow at 41.5°,where the particle mass flux is high,the impact speed is large,and the function value related to the impact angle approaches the maximum value;and the oil film on the pipe wall can slow down the particle movement speed and protect the pipeline from erosion.The research results have a certain guiding role for the safe operation of oil and gas field development projects.