Investigation of Continuous-Flow Mixing of Non-Newtonian Fluids through Advanced Flow Visualization Techniques (e.g. Tomography and Ultrasonic Velocimetry) and Computational Fluid Dynamics

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The mixing of non-Newtonian fluids plays a significant role in chemical, biochemical, food, polymer, pulp and paper, cosmetic, wastewater treatment, and pharmaceutical industries. Previous studies have focused on the mixing of non-Newtonian fluids in the batch mode and little information is available regarding the continuous-flow mixing of these complex fluids. Continuous-flow mixing is prevalent in most of chemical and allied process industries because it provides high production rates, improves process control, and saves operation time and labor costs. The studies conducted in our research lab show that the complex rheology of non-Newtonian fluids creates non-ideal flows (e.g. channeling, recirculation, and dead zone) that significantly affect the efficiency of continuous-flow mixers. A comprehensive literature review reveals that our current understanding and implementation of continuous mixing of non-Newtonian fluids is insufficient to ensure good mixing. The current design of continuous mixing of non-Newtonian fluids is based on limited published information, and trial and error method. In fact, this issue has not been fully delineated yet and there is a clear need to explore this topic in more detail. Thus, our long term research program goal is to develop methodology and tools to design continuous mixing systems for fluids with complex rheology through advanced flow visualization techniques (e.g. tomography and ultrasonic velocimetry) and advanced computational fluid dynamics (CFD) methods. The work is of great importance to the chemical industry of Canada. Mixing is a critical unit operation and is not operating to its fullest potential. Failure to provide the necessary mixing may result in severe manufacturing problems ranging from costly corrections in the plant to complete failure of a process. The annual loss due to poor mixing is estimated at $10 billion in the North America chemical industry alone. The proposed experimental and modeling research program will improve our understanding of continuous mixing of non-Newtonian fluids and enable us to develop the reliable design criteria. Applying the findings of this study will improve variability reduction in the continuous mixing processes. This will lead to capital cost savings, chemical cost reduction, improved equipment design and selection, more reliable process monitoring and control, increased throughput for existing plant, improved quality of products, and more efficient use of power. Thus, the proposed research will contribute to the increased economic activity of the Canadian chemical industry, and will impact our society, quality of life, health and environment. It will also contribute to the education and training of highly qualified personnel (HQP) in the field of mixing technology, advanced flow visualization techniques, computational fluid dynamics, rheology, and dynamic modeling and identification.