多相流管道泥砂颗粒冲蚀机制研究

The multiphase flow with sand particles is widely existed in the process of offshore oil and gas pipeline transportation and hydrate exploitation. The erosion wear of the multiphase flow pipelines caused by sand particles has become the main hazard in the process of marine resources exploitation. In this project, theoretical analysis, numerical simulation and experimental researches are combined together to study the sand particles erosion mechanism in multiphase flow pipe. The method is based on particle dynamics and multiphase fluid mechanics which are used to analyze the property of multiphase flow with sand and the characteristics of particle distribution and establish the dynamic model of sand particles in multiphase flow such as Taylor bubbles, liquid film and liquid slug. What is more, sand particles migration dynamics model is also built. The near wall turbulence burst prediction model is built to study the interaction between particle motion and near wall coherent structure in order to get the particle trajectory in multi-phase flow. The erosion mechanism of metal surface can be studied and revealed based on the theories of contact mechanics and tribology. The erosion model with gas-liquid-solid particle-pipe wall complex coupling is established to predict and control the erosion process of sand particles in multiphase flow. The results of this project will enrich and develop the theories of the erosion in multiphase flow and anti-erosion properties of pipelines. Additionally, it is of great scientific significance and engineering application value for exploitation of marine resources as well as the enacting of protecting specification to provide necessary theoretical and technical support.

含泥砂颗粒的多相流动广泛存在于海上油气和水合物开发的管输过程中，多相流场中泥砂颗粒对管壁的冲蚀磨损已成为当前海上资源开发的主要安全隐患。本项目采用理论分析、数值模拟与实验研究相结合的方法，基于颗粒动力学、多相流体力学，分析含泥砂颗粒多相流动特性及颗粒分布特征，建立泥砂颗粒在多相流气核、液膜、段塞体单元中的动力学模型以及泥砂颗粒相间迁移动力学模型。建立近壁面湍流猝发预测模型，研究颗粒运动与近壁面拟序结构之间的相互作用关系，求解多相流泥砂颗粒轨迹。基于接触力学、摩擦学等学科理论，研究并揭示金属表面冲蚀损失机制。建立气-液-固体颗粒-管壁多向耦合的管道冲蚀模型，发展管道防冲蚀的基础理论，实现多相流中泥砂颗粒冲蚀过程的预测和控制。项目预测成果将完善多相流条件下泥砂颗粒冲蚀理论，为实现海上资源安全开发以及制定相关防护规范提供必要的理论和技术支撑，具有重要的科学意义和应用价值。

本项目以含砂多相流条件下的管道冲蚀特性为研究目标。采用理论分析、数值模拟和实验研究相结合的方法。基于颗粒动力学、多相流体力学以及接触力学等理论，求解泥砂颗粒在多相流中的分布特性与运动轨迹，揭示多相流场下管道的冲蚀损伤机制。主要的研究工作及创新点如下：.（1）建立了耦合多相流模型与离散相模型的数值模型以求解颗粒在多相流场内的运动轨迹。分析了颗粒在气液相中的分布与运动特性，揭示了液膜对颗粒的缓冲作用以及弯头处冲蚀形貌的产生机制。.（2）采用双向耦合的Euler-Lagrange方法求解气固两相流。引入DSMC方法计算颗粒间的碰撞行为，采用少量采样颗粒取代真实颗粒，实现了颗粒碰撞的随机判定，准确获得了固体颗粒在弯管中的实时运动与碰撞轨迹。.（3）对冲击载荷下材料表面的应力-应变特性进行了研究。分析了颗粒形状、颗粒运动状态以及表面加工硬化特性对冲蚀行为影响，量化了冲蚀速率与颗粒浓度、颗粒旋转之间的相关性。引入颗粒浓度的影响因素，修正了Bitter的冲蚀损伤预测模型，从而提高了预测精度。.（4）基于拉格朗日颗粒追踪法，实现颗粒-壁面碰撞特征精准反演。建立了气-液-颗粒-管壁多相耦合的颗粒冲蚀预测模型，经过与实验数据的对比证明了模型的预测精度。.本研究发表论文30篇，其中SCI检索20篇，EI检索4篇。申请专利4项，获省部级科技奖励2项，申请到延伸课题1项。该研究完善了多相流条件下泥砂颗粒冲蚀理论，为实现天然气水合物以及页岩气的高效开发提供了理论与技术支撑，对维护油气管道安全生产具有重要的科学意义和应用价值。