Dynamics of particles and bubbles in water and viscoplastic flow mixtures

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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.