Mixing in complex fluids: modeling and experiments

自然界和工业中的各种过程都涉及到具有不寻常机械响应的流体。在涉及石油、固井和废水等复杂流体混合的行业中，由于缺乏科学知识和先进的技术模型，过程工程在很大程度上仍然是经验的。这些过程通常由不同阶段的(生物)化学、机械和热相互作用所支配。这些行业的技术进步有赖于对多学科和多尺度潜在现象的更好理解。这项为期5年的计划提出了一种多学科的方法来解决这一差距。理论和实验研究方法将系统地研究复杂流体中的自由混合和强迫混合。该程序的创新之处在于：(I)非均质复杂流体特性和(Ii)非定常流体动力学在描述混合流动中的应用。*将开发复杂流体混合的模型，并根据实验进行验证。流体流变学和主要不稳定模式抑制平流的临界极限将通过数值和数学分析来研究。系统的数值研究将揭示不同流体性质和初始构型的流动发展趋势。将进行补充的实验研究，以表征流动发展趋势，揭示潜在的物理特性，并确定主要的流变特征。实验研究将演示强迫混合流的演变。实验的无量纲分析将确定流体的流变性、初始条件和搅拌器配置的影响。将开发工程模型来预测混合效率，并为最佳设计实践和操作规程提供信息。*每年有超过1500亿升未经处理的废水(污水)被倾倒到加拿大的水道中。除了巨大的环境和经济成本以及相关的健康问题外，废弃污水是沼气的一个重要来源，但在很大程度上被忽视了。在这个项目中产生的基础知识将被用来开发污水处理的水动力学模型。这一建模工具允许评估当前的设计和实践以及新技术的概念和比较。*总体观点是促进对复杂流体多相流的基本理解，开创最优工程模型，并促进创新的清洁能源实践。这些工具和模型可移植到采油、固井和制造业的许多其他应用中。该计划对能源和废水行业的经济和环境影响具有重大潜力，并为石油、水泥、化妆品、食品和生物能源行业培养具有竞争力的专业知识。

Various processes in nature and industry involve fluids with unusual mechanical responses. Process engineering in industries that involve mixing of such complex fluids, e.g., petroleum, cementing and wastewater, have remained largely empirical due a lack of scientific knowledge and advanced technological models. These processes are often governed by (bio)chemical, mechanical and thermal interaction of different phases. Technological advances in these industries rely on a better understanding of the multi-disciplinary and multi-scale underlying phenomena. This 5-year program proposes a multidisciplinary approach to address this gap. Theoretical and experimental research methodologies will be used systematically to investigate free and forced mixing in complex fluids. The novelty of the proposed program is in incorporating (i) heterogeneous complex fluid features and (ii) unsteady fluid dynamics in characterizing mixing flows. ******Models of mixing of complex fluids will be developed and validated against experiments. Critical limits where advection is suppressed by fluid rheology and the primary instability modes will be studied using numerical and mathematical analysis. Systematic numerical studies will reveal flow development trends for different fluid properties and initial configurations. Complementary experimental studies will be conducted to characterize flow development trends, reveal underlying physics and identify dominant rheological features. Experimental studies will demonstrate evolution of forced mixing flows. Dimensionless analysis of the experiments will establish the effect of fluids' rheology, initial condition and stirrer configuration. Engineering models will be developed to predict mixing efficiency and inform best design practices and operation protocols. ******Over 150 billion liters of undertreated wastewater (sewage) is dumped into Canadian waterways every year. Aside from the formidable environmental and economical costs and the associated health concerns, the discarded sewage is a significant source of biogas that has been largely overlooked. The fundamental knowledge produced in this program will be leveraged to develop hydrodynamic models of sewage treatment. This modeling tool allows assessment of the current designs and practices and conception and comparison of novel technologies.******The overarching perspective is to advance the fundamental understanding of multiphase flow of complex fluids, pioneer optimal engineering models and contribute to innovative clean-energy practices. The tools and models are transferrable to many other applications in oil recovery, cementing, and manufacturing industry. The program has a significant potential for economical and environmental impact on energy and wastewater industries and trains HQP with competitive expertise for oil, cement, cosmetics, food and bioenergy industries.