Computational Study of Three Dimensional Concentrated Emulsions and Foams with Surfactant Effects

美国国家科学基金会-化学运输系统分部颗粒多相过程计划（1415）提案编号：0650826主要研究者：Higdon，Jonathan所属机构： 美国伊利诺伊大学厄本那-香槟分校提案题目：含表面活性剂的三维浓乳液和泡沫的计算研究智力成果多相流体流动在石油、化工、食品加工、个人护理产品和其他工业的各种工业操作中都会遇到。强化采油工艺构成了多相流体混合物流过复杂多孔介质的间隙空间的一个重要应用。多相流体混合物也用于许多涉及通过管道和毛细管的流动的制造操作中。表面活性剂在涉及多相流体的所有工业过程中几乎无处不在。添加这些试剂以优化加工条件，稳定或不稳定多相流体，调节其粘度、弹性或屈服应力，提出了一个广泛的研究计划，其中将对高浓度乳液和分散相泡沫进行大规模三维多相流模拟体积分数高达95%。系统参数包括毛细管数Ca、体积分数f、粘度比（液滴/溶剂）、表面活性剂性质和液滴尺寸范围/多分散性。流动分析将集中在三个方面：（1）表征线性剪切流中悬浮液的流变学和相行为，（2）分析表面活性剂传输和表面活性剂改变悬浮液行为的微观机制，以及（3）分析通过三维模型多孔介质的多相流体流动。模拟将包括系统与O（1000）液滴，这将提供足够的规模来捕捉这些复杂的多相流中表现出的物理现象的广泛范围。实验和模拟的详细比较将被进行，所提出的研究的成功完成将提供一个基本的描述的流变学和相行为的多相流包括乳液和泡沫。这些三维系统的模拟的发展代表了一个重大的进步，这将最终允许直接比较与真实的多相流，并促进定量比较与实验结果。表面活性剂在高浓度流动体系中传输的微观分析将为我们理解表面活性剂对浓缩泡沫和乳状液的影响提供一个根本性的进步。更广泛的影响拟议的研究提供了广泛的影响，科学研究和教育，并通过多种渠道为社会提供福利。这种计算开发工作的最终目标是提供算法库，最终用户可以采用该算法库来开发大规模并行集群上的多相流模拟。拟议的活动将为流体动力学、流变学和计算科学的研究生研究助理提供培训。通过基于网络的分发，我们以语言和插图向广大非技术受众提供了我们的研究成果。在对社会的直接利益方面，该研究为消费者和工业应用的新型加工方法的设计提供了所需的技术背景。这项工作的成功完成将首次提供一个强大的计算工具包，用于优化各种工业过程中不同表面活性剂的设计和选择。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)Proposal Number: 0650826Principal Investigators: Higdon, JonathanAffiliation: University of Illinois at Urbana-ChampaignProposal Title: Computational Study of Three Dimensional Concentrated Emulsions and Foams with Surfactant EffectsIntellectual MeritMultiphase fluid flows are encountered in a wide array of industrial operations in the petroleum, chemical, food processing, personal care products and other industries. Enhanced oil recovery processes constitute one important application with multiphase fluid mixtures flowing through the interstitial spaces of a complex porous medium. Multiphase fluid mixtures are also utilized in many manufacturing operations involving flow through pipelines and capillaries. Surfactants are nearly omnipresent in all industrial processes involving multiphase fluids. These agents are added to optimize the processing conditions, stabilizing or destabilizing the multiphase fluid, adjusting its viscosity, elasticity or yield stress, modifying droplet size or size distribution or affecting numerous other properties specific to a given product or industry.A broad plan of research is proposed where large scale three dimensional multiphase flow simulations will be conducted for highly concentrated emulsions and foams for dispersed phase volume fractions up to 95%. The system parameters include capillary number Ca, volume fraction f, viscosity ratio (droplet/solvent), surfactant properties and droplet size range/polydispersity. The flow analysis will focus on three thrusts: (1) to characterize the rheology and phase behavior of the suspensions in linear shear flows, (2) to analyze surfactant transport and the microscale mechanisms through which the surfactants modify suspension behavior, and (3) to analyze the multiphase fluid flow through three dimensional model porous media. The simulations will encompass systems with up to O(1000) droplets which will provide sufficient scale to capture the broad range of physical phenomena exhibited in these complex multiphase flows. Detailed comparisons of experiments and simulations will be conducted.The successful completion of the proposed research will provide a fundamental description of the rheology and phase behavior of multiphase flows involving emulsions and foams. The development of these simulations for three dimensional systems represents a major advance which will finally allow a direct comparison with real multiphase flows and facilitate quantitative comparison with experimental results. The microscale analysis of surfactant transport in highly concentrated flowing systems will provide a fundamental advance in our understanding of surfactant effects on concentrated foams and emulsions.Broader ImpactThe proposed research provides a broad impact on scientific research and education and provides benefit to society through a number of diverse channels. The ultimate goal of this computational development effort is to provide libraries of algorithms which end users may employ to develop multiphase flow simulations on large scale parallel clusters. The proposed activity will provide for the training of graduate research assistants in fluid dynamics, rheology and in computational science.Through web based distribution, we have made our research results available in language and illustrations accessible to a broad non-technical audience. In terms of direct benefits to society, the research provides the technological background required for the design of novel processing methods for consumer and industrial applications. The successful completion of this work would for the first time provide a robust computational toolkit for optimizing the design and selection of different surfactants for a broad range of industrial processes.