Collaborative Research: Stability and dispersion of viscoelastic flows through porous media

合作研究：多孔介质粘弹性流的稳定性和分散性

• 批准号: 2141349
• 负责人: Jeffrey Guasto
• 金额: $ 28.7万
• 依托单位: Tufts University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2141349&HistoricalAwards=false
• 关键词: Collaborative; Research; Stability; dispersion; viscoelastic

Viscoelastic fluids, including polymers and biological materials, exhibit mechanical properties of both fluids and solids. When driven through porous materials, viscoelastic fluids exhibit an abrupt transition to chaotic flow, which is a key feature of enhanced mixing that regulates a vast array of important geological, biological, and industrial processes. Despite our deep understanding of viscoelastic flows in simple model geometries, predicting their flow properties through the intricate, irregular crevices of porous materials remains an outstanding challenge. The goal of this work is to quantify viscoelastic fluid flows in a range of model and realistic porous media and determine how microscopic geometry affects the macroscopic flow and transport properties of viscoelastic fluids. The outcomes of this project will have direct implications for extraction and bioremediation efficiency in rock and soil, minimizing power consumption and cost in polymer processing, and understanding biofilm mechanics that affect soil ecology and infections in humans. Under this project, workshops will be organized to promote early career development of scientists in the field, several undergraduate and graduate students will receive research training, and aspects of this work will be integrated into microfluidics and complex fluids courses.The stability of viscoelastic fluid flows through porous media strongly depends upon the disorder and connectivity of successive pores. The memory of elastic stresses couples advection to pore microstructure making for exquisitely complex stability criteria, and emphasizing the need to consider the Lagrangian character of polymeric flows. A dearth of quantitative studies across relevant two- and three-dimensional flow geometries has yielded often conflicting outcomes and has inhibited our ability to forecast the dispersive transport properties of these systems. To resolve these key deficiencies in our current understanding of viscoelastic flows through porous media, the following principle aims will be achieved through the integration of microfluidic experiments and numerical simulations: (1) Determine the role of geometrical structure, disorder, and porosity on viscoelastic instability in two-dimensional porous media flows. (2) Establish the effect of geometry and viscoelasticity on dispersion in porous media through analysis of Lagrangian coherent structures. (3) Elucidate the role of three-dimensionality in the viscoelastic stability and resultant transport properties of porous media flows. This work will establish a direct link between fluid stress, stretching kinematics, and transport.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

包括聚合物和生物材料在内的粘弹性流体均表现出流体和固体的机械性能。当通过多孔材料驱动时，粘弹性流体会突然过渡到混沌流，这是增强混合的关键特征，可以调节大量重要的地质，生物学和工业过程。尽管我们对简单模型几何形状中的粘弹性流有深刻的了解，但通过复杂的多孔材料的不规则缝隙来预测其流量性能仍然是一个重大挑战。这项工作的目的是量化一系列模型和逼真的多孔介质中的粘弹性流体流，并确定微观几何形状如何影响粘弹性流体的宏观流量和运输特性。该项目的结果将直接影响岩石和土壤中的提取和生物修复效率，最大程度地减少聚合物加工的功耗和成本，并了解影响人类土壤生态学和感染的生物膜力学。在该项目下，将组织研讨会以促进该领域的科学家的早期职业发展，几位本科生和研究生将接受研究培训，这项工作的各个方面将集成到微流体和复杂的流体课程中。通过多孔培养基通过多孔媒体的稳定性，强烈依赖于连续毛孔的疾病和连接性。弹性应力的记忆使夫妻对孔微观结构的对流进行精确复杂的稳定性标准，并强调需要考虑聚合物流的拉格朗日特征。在相关的二维流量几何形状上涉及的定量研究的匮乏经常产生相互矛盾的结果，并抑制了我们预测这些系统分散运输特性的能力。为了解决这些关键缺陷在我们当前对通过多孔介质的粘弹性流动的理解中，通过将微流体实验和数值模拟的整合结合来实现以下原理：（1）确定几何结构，混乱和孔隙率在二维孔孔媒体中粘弹性不稳定性的作用。 （2）通过分析拉格朗日连贯的结构，建立几何和粘弹性对多孔介质分散的影响。 （3）阐明了三维在粘弹性稳定性和多孔介质流的运输特性中的作用。这项工作将在流体压力，扩展运动学和运输之间建立直接联系。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评论标准来评估值得支持的。