高压管汇冲蚀速率数值模拟新方法研究

Research on New Numerical Simulation Method of Erosion Rate of High Pressure Manifold

目前关于冲蚀速率的计算还是以半经验计算模型为主,各模型预测的结果并不是很精确,DPM模型忽略了离子间碰撞的影响,且在固相颗粒体积分数较高时预测的准确性有限。为此,使用CFD方法,分别采用DPM模型和DDPM模型,分析了弯径比、压裂工况参数、固相颗粒物理特性及颗粒斯托克斯系数对高压管汇冲蚀速率及冲蚀区域的影响。研究结果表明:DDPM模型考虑四相耦合,考虑了颗粒之间的碰撞和作用力,在模拟颗粒轨迹上要优于DPM模型;最主要的冲蚀区域还是弯头出口外壁区域,颗粒形状系数小于0.5时,在弯头15°~45°偏转角截面冲蚀减轻,影响冲蚀区域的因素是弯径比和颗粒粒径;在斯托克斯系数St>1与St<1时颗粒轨迹出现明显差别,冲蚀区域出现一定改变。所得结论对高压管汇的结构改进及剩余寿命评估具有理论和工程应用意义。

At present,the calculation of erosion rate is mainly based on semi-empirical calculation models.The prediction results of the models are not very accurate.The DPM model ignores the impact of particle collisions,resulting in limited prediction accuracy when the volume fraction of solid particles is high.In view of this,using the CFD method,the DPM model and the DDPM model are applied respectively,to analyze the effects of bend-diameter ratio,fracturing parameters,solid particle physical properties and particle’s Stokes coefficient on the erosion rate and erosion zone of the high pressure manifold.The research results show that the DDPM model,considering four-phase coupling and the collision and force between particles,is better than the DPM model in simulating particle trajectories.The most severe erosion area is the outer wall area of the elbow outlet.When the particle shape coefficient is less than 0.5,the erosion at the 15°~45°bending angle cross-section of the elbow is reduced,and there is no obvious erosion.The factors affecting the erosion area are the bend-diameter ratio and the particle size.When St>1 and St<1,the particle trajectory appears obvious difference,and there is a certain change in the erosion area.The conclusions obtained have theoretical and engineering application significance for the structural improvement and remaining life assessment of high pressure manifolds.