Dynamics of particles and bubbles in water and viscoplastic flow mixtures

水和粘塑性流动混合物中颗粒和气泡的动力学

• 批准号: RGPIN-2022-04787
• 负责人: Azimi, AmirHossein
• 金额: $ 1.89万
• 依托单位: Lakehead University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749298
• 关键词: Dynamics; particles; bubbles; water; viscoplastic

Mining and oil sand industries have been expanded in Canada due to the global need. However, existing mining and oil-sand activities require immense water consumption during ore extraction and mineral processing. The concentrated suspended minerals in water behave like non-Newtonian viscoplastic flow. In addition, most experimental studies were performed in stagnant ambient whereas ocean, lakes, tailing ponds, and natural streams contain background turbulence, which was not considered in previous studies. Efficient particle mixing and separation mechanisms are needed to minimize the footprint of mining activities and freshwater intake. This can be achieved by better understanding of particle dynamics in turbulent water and viscoplastic flow ambient. Urban populations in Canada have greatly increased, resulting in increased demand for fresh water and wastewater treatment, which can be addressed by enhancing water quality. Many mining and environmental processes use air injections in non-Newtonian fluids as well. The proposed research program will focus on the hydrodynamics of sediment-laden jets, particle clouds, and bubbly jets/plumes in the presence of background turbulence, and will investigate the motion of solid objects, particles, and bubbles in viscoplastic ambient mixtures. Understanding the dynamic interactions of air bubbles or sand particles with the ambient water is important for proper design and optimization of engineering systems. The complexity of the phenomenon and the challenge in understanding the effects of controlling parameters such as nozzle size, particle size, release height, and angle of nozzles requires considering both experimental and numerical approaches. The proposed NSERC-Discovery program consists of four projects, the goals of which are to perform scaling analysis and identify important parameters such as nozzle diameter, particle size, release height, release angle, and particle size distribution on the motion of particle clouds; to test and characterize the rheology of non-Newtonian fluid mixtures such as yield stress and apparent viscosity; to identify the mechanisms that improve oxygen transfer by reducing bubble size and bubble velocity; to determine nozzle diameter, nozzle angle, and airflow discharge based on the scaling analysis, and test the optimum air-water discharge ratio in bubbly jets and plumes; to determine the regime classification of bubble plumes in viscoplastic flow mixtures; to perform numerical simulation on the motion of solid objects in stagnant ambient water, controlled background turbulence, and viscoplastic mixtures and to conduct validation tests on the motion of bubbly jets in stagnant ambient water and investigate bubble breakup and coalescence in two adjacent bubbly jets with an angle. The outcomes of the proposed program will help Canadians to secure more fresh water and enable industries to efficiently reclaim and reuse water for their activities with the proposed models.

由于全球的需求，加拿大的采矿和油砂工业已经扩大。然而，现有的采矿和油砂活动在矿石开采和矿物加工过程中需要消耗大量的水。水中的浓缩悬浮矿物质表现为非牛顿粘塑性流动。此外，大多数实验研究都是在静止的环境中进行的，而海洋，湖泊，尾矿池和天然河流含有背景湍流，这在以前的研究中没有考虑。需要有效的颗粒混合和分离机制，以尽量减少采矿活动的足迹和淡水摄入量。这可以通过更好地理解湍流水和粘塑性流动环境中的颗粒动力学来实现。加拿大的城市人口大大增加，导致对淡水和废水处理的需求增加，这可以通过提高水质来解决。许多采矿和环境工艺也在非牛顿流体中使用空气注入。拟议的研究计划将侧重于在背景湍流的存在下，含泥沙的射流，颗粒云和气泡射流/羽流的流体动力学，并将研究粘塑性环境混合物中固体物体，颗粒和气泡的运动。了解气泡或沙粒与环境水的动态相互作用对于工程系统的正确设计和优化非常重要。 这一现象的复杂性和理解控制参数（如喷嘴尺寸、颗粒尺寸、释放高度和喷嘴角度）的影响的挑战需要同时考虑实验和数值方法。NSERC-Discovery计划由四个项目组成，其目标是进行缩放分析，确定影响颗粒云运动的重要参数，如喷嘴直径、颗粒尺寸、释放高度、释放角和颗粒尺寸分布;测试和表征非牛顿流体混合物的流变性，如屈服应力和表观粘度;确定通过减小气泡尺寸和气泡速度来改善氧传递的机制;根据缩放分析确定喷嘴直径、喷嘴角度和气流排放，并测试气泡射流和羽流中的最佳空气-水排放比;确定粘塑性流动混合物中气泡羽流的状态分类;对静止环境水中固体物体的运动进行数值模拟，受控背景湍流，和粘塑性混合物，并对气泡射流在停滞环境水中的运动进行验证试验，并研究两个相邻气泡射流中气泡的破裂和合并有角度的。拟议方案的成果将帮助加拿大人获得更多的淡水，并使工业能够有效地回收和再利用水，用于拟议模式的活动。