Mesoscopic modelling of erosion in particle-laden flow systems

全球近70%的碳氢化合物产自固结不良的砂岩储层，这些储层不可避免地与砂混合。出砂-小至0.01重量% -会导致严重的侵蚀问题，如管道、井下油管和包括泵和阀在内的生产设备的退化。撞击颗粒（通常在10-300微米范围内）充当微型机床，其切入表面材料并产生材料碎片[10]，对表面层造成过度损坏并降低腐蚀抑制剂的有效性。增强的腐蚀性降解反过来又会加速侵蚀，导致表面金属严重和快速损失（冲刷）。沿流体输送管道的长度沿着缺乏实时和局部测量选项使得难以防止灾难性故障。侵蚀机制取决于多个因素的相互作用，如颗粒碰撞率，尺寸，形状，碰撞角度和速度，以及颗粒表面材料的属性。最近对23种不同侵蚀模型的审查得出结论，由于缺乏对基本物理机制的基本了解，上述许多参数没有充分纳入模型。这导致了过度保守的模型的发展，这对石油/天然气生产线和设备的效率和制造成本产生了不利影响。因此，我们迫切需要预测能力来评估现有石油/天然气生产流程系统的使用寿命，并优化新系统的设计。然而，只有当颗粒的动态行为能够单独和集体捕获时，我们在预测颗粒侵蚀影响方面的能力才有可能逐步改变。因此，关键的研究问题是了解在侵蚀过程中的冲击固体颗粒的动力学作用，使定量预测颗粒的侵蚀影响和质量从表面去除。我们将通过开发一种新的经过验证的多尺度计算工具来应对这一研究挑战，我们的目标是通过开发一种全新的基于第一性原理的计算工具来量化流动系统中颗粒对表面的侵蚀影响，从而改变目前的特设侵蚀建模方法。因此，我们提出了以下目标：-通过在高颗粒浓度区域扩展CFD-DEM方法，将流动湍流和颗粒表面碰撞速率关联起来。为了确定撞击颗粒对表面的侵蚀作用，将利用周波理论来评估表面损伤，并将通过实验进行校准和验证。

Nearly 70% of hydrocarbons are produced from poorly consolidated sandstone reservoirs worldwide which are inevitably mixed with sands. Sand production - as small as 0.01w\% - leads to major erosion problems such as degradation of pipelines, down-hole tubing and production equipment including pumps and valves. The impinging particles (usually in the range 10-300 microns) act as miniature machine tools which cut into the surface material and generate material chips [10], causing excessive damage to the surface layer and reducing the effectiveness of corrosion inhibitors. The enhanced corrosive degradation will in turn accelerate erosion resulting in severe and rapid loss of surface metal (washout). A lack of real-time and local measurement options along length of the fluid-carrying pipelines makes prevention of catastrophic failure difficult. The erosion mechanisms depend on the interplay of multiple factors such as particle collision rate, size, shape, impinging angles and velocities, and particle-surface material properties. A recent review of 23 different erosion models concludes that many of the aforementioned parameters are not adequately included in the models due to a lack of fundamental understanding of the underlying physical mechanisms. This has resulted in the development of excessively conservative models which are adversely affecting efficiency and manufacturing costs of oil/gas production lines and equipment. Therefore, we urgently need predictive capability to assess the service life of existing oil/gas production flow systems, and to optimise the design of new ones.However, a step-change of our capability in predicting erosive impact of particles will only be possible if their dynamical behaviour can be captured both individually and collectively. The key research question is therefore to understand the dynamical role of impinging solid particles in the erosion process, enabling quantitative prediction of erosive impact of particles and mass removal from the surface. We will tackle this research challenge by developing a new validated multiscale computational tool.We aim to transform the current ad hoc approach to modelling erosion by developing a totally new computational tool based on first principles to quantify erosive impact of particles on surfaces in flow systems. Therefore, we set out the following objectives: - To correlate the flow turbulence and the rate of particle-surface collisions by extending the CFD-DEM approach in the regions of high particle concentration.- To determine the erosive effect of impinging particles on surface, the peridynamics theory will be utilised to assess surface damage, which will be calibrated and validated experimentally.