Investigation of continuous-flow mixing of non-newtonian fluids through tomography, ultrasonic velocimetry and computational fluid dynamics techniques

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Continuous-flow mixing of non-Newtonian fluids is a vital component to many processes including polymerization, fermentation, waste water treatment, and pulp and paper manufacturing because of its demonstrated ability to improve product uniformity and minimize shut down, loading and unloading times. The current design of continuous mixing of non-Newtonian fluids is based on limited published information, and trial and error methods. The assumption of ideal mixing has traditionally been used to design these mixing processes. However, the complex rheology displayed by non-Newtonian fluids can create considerable deviation from ideal mixing. Studies show that the non-ideal flow such as short circuiting, recirculation, and dead zones significantly affect the performance of continuous mixing processes. In fact, a thorough search of the literature suggests that our current understanding and implementation of continuous mixing of non-Newtonian fluids is insufficient to ensure good mixing. In particular, design criteria incorporating mixing dynamics are needed so that acceptable mixing responses can be attained from continuous mixing systems. Thus, the 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 methods. The work is of great importance to the chemical industry of Canada. The annual loss due to poor mixing is estimated at $10 billion in the North America chemical industry alone [Handbook of Industrial Mixing]. The proposed experimental and modeling research program will improve our understanding of continuous mixing of non-Newtonian fluids and answer some of the fundamental questions about the design criteria. Applying the finding of this study will improve variability reduction in the continuous mixing processes. This will lead to capital cost savings, chemical cost reduction, improved quality of products, and more efficient use of power. The proposed research will contribute to the training of highly qualified personnel by actively involving Ph.D. and master's students.