天然气携砂对缩扩管冲蚀磨损分析

Analysis on erosive wear at the pipe contraction and expansion section caused by natural gas carrying sand

为探究天然气携砂在缩扩管处气固两相流冲蚀磨损机理,采用计算流体动力学—离散单元法(Computational Fluid Dynamics-Discrete Element Method, CFD-DEM)耦合方法,建立了CFD-DEM模型,分析了粒径、颗粒质量流率、缩扩管管径比、连续相流速对缩扩管冲蚀磨损的影响。研究表明,粒径和最大磨损深度成正相关,粒径1.2 mm时最大磨损深度为粒径0.4 mm时的1.7倍。最大磨损深度与颗粒质量流率和连续相流速呈正比关系。随着缩扩管管径比增大,最大磨损深度先减小后增大。最大磨损深度受上述因素的影响会发生不同程度的增大或减小,影响程度从大到小依次为连续相流速、缩扩管管径比、颗粒粒径、颗粒质量流率。模拟结果可为缩扩管优化设计提供思路,降低天然气输运过程中因磨损导致管道泄漏的风险。

In order to explore the erosive wear mechanism of gas-solid two-phase flow carrying sand in natural gas pipelines at the pipe contraction and expansion section,a Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)coupling approach was selected to develop a CFD-DEM model in the pipe contraction and expansion sections.This study analyzed the influence of varying particle size,mass flow rates of particles,diameter ratios of the pipe contraction and expansion sections,and flow velocities of the continuous phase on the erosive wear at the contraction and expansion section within the pipe.The research results reveal a direct relationship between particle size and the maximum wear depth,with a 1.2 mm particle size exhibiting a maximum wear depth 1.7 times greater than that of a 0.4 mm particle.The maximum wear depth increases linearly with the mass flow rate and flow velocity of particles.As the diameter ratio of the contraction section increases,the maximum wear depth initially decreases before it starts to rise again.The maximum wear depth is subject to varying degrees of increase or decrease as influenced by the aforementioned factors.The order of impact of maximum wear depth from high to low is:continuous phase flow velocity>pipe diameter ratio>particle size>particle mass flow rate.The simulation results in this paper can provide valuable insights for the optimization of the design for pipe contraction and expansion section,thereby mitigating the risk of pipeline leak caused by wear during natural gas transportation.