CMG POST-DOC: Multiscale multiphase flow simulations of dense vesicular particle suspensions.

CMG POST-DOC：致密囊泡颗粒悬浮液的多尺度多相流模拟。

• 批准号: 0724560
• 负责人: Martin Saar
• 金额: $ 27.29万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0724560&HistoricalAwards=false
• 关键词: CMG; POST; DOC; Multiscale; multiphase

Many fluids in science and engineering (listed below) are vesicular particle suspensions that exhibit complex non-Newtonian rheological behavior during both bulk fluid flow and during flow through porous media. The complexities of such fluids? flow behavior cannot be captured by standard Navier-Stokes equations and are the result of microscale particle, bubble, and liquid interactions during deformation. Limited knowledge connecting these microscale interactions to resultant macroscopic behavior restricts attempts to infer flow processes from (field) observations and to predict the behavior of these fluids in natural settings or in engineered processes. The objective of the proposed research is therefore to numerically model the deformation and flow of a variety of dense, vesicular particle suspensions by reproducing 1) individual particle and bubble interactions at the microscale, 2) representative elementary volume behavior at the macroscale, and 3) larger fluid flow processes on laboratory and field scales. This objective will be achieved by first developing a numerical simulator for fluid flow and suspended inclusion (particles, bubbles) motion, and then employing these simulations, as well as thermomechanical methods, to derive physically viable, large-scale continuum-mechanical models, that account for the effects of microscale particle, bubble, and liquid interactions. The simulator will be a hybrid computer code that combines a fluid flow code with a code to model the motion of particles in dry granular materials. The predictive capabilities of the hybrid code and the derived continuum-mechanical models will be tested against analogue material and remelt experiments as well as against analytic solutions where available.Many important flow phenomena in the sciences and in engineering are the result of the complicated flow behavior of dense, vesicular particle suspensions that lie in between fluids and solids, sometimes called slurries. Examples of processes that involve slurries include flow of magma in volcanic conduits affecting volcanic eruption dynamics (explosive versus effusive) and heat transfer with implications for the assessment of volcanic hazards and renewable geothermal energy resources. Other geoscience applications include landslides, mud flows, and lahars that also represent mixtures of liquids, particles, and (sometimes) bubbles with implications for the assessment of geohazards and (human-made and natural) environmental impacts. Specific flow behaviors of slurries also play an important role in biological and medical processes such as blood flow through veins or microbe transport in groundwater. Engineering applications of this project may include food, foam, cement, gel, and ceramics processing. The research proposed here aims at developing a computer code to simulate particle and bubble interactions in slurries at a very small scale to determine how the bulk substance deforms and flows and how it conducts gases. Insights gained at small scales are then up-scaled to the actual spatial and temporal scale of interest. This approach is difficult but important, because small-scale interactions of inclusions (particles, bubbles) have a large effect on the complicated (non-Newtonian) flow behavior of these fluids, where the otherwise often-invoked Navier-Stokes equations can typically not be employed. Therefore, predicting the flow behavior of dense slurries, based on their inclusion properties, has the potential to significantly impact science and engineering dealing with such non-standard, but often encountered and important, fluids. In addition, this project supports a postdoctoral researcher and, through interactions in laboratories, undergraduate and graduate students, who receive interdisciplinary training in mathematical, computer, material, and geophysical science. The developed computer code is expected to be of interest to numerous science and engineering disciplines.

科学和工程中的许多流体（如下所列）是泡状颗粒悬浮液，其在本体流体流动期间和在流动通过多孔介质期间都表现出复杂的非牛顿流变行为。这种液体的复杂性？流动行为不能被标准的Navier-Stokes方程捕获，并且是变形期间微尺度颗粒、气泡和液体相互作用的结果。有限的知识连接这些微观尺度的相互作用所产生的宏观行为限制了试图推断流动过程（现场）观察和预测这些流体在自然环境中的行为或工程过程。因此，所提出的研究的目的是通过再现1）微观尺度下的单个颗粒和气泡相互作用，2）宏观尺度下的代表性基本体积行为，以及3）实验室和现场尺度上的较大流体流动过程，对各种致密的泡状颗粒悬浮液的变形和流动进行数值模拟。这一目标将通过首先开发流体流动和悬浮夹杂物（颗粒，气泡）运动的数值模拟器，然后采用这些模拟，以及热机械方法，推导出物理上可行的，大规模的连续力学模型，占微尺度颗粒，气泡和液体相互作用的影响。该模拟器将是一个混合的计算机代码，结合了流体流动代码与代码来模拟干燥颗粒材料中颗粒的运动。混合代码的预测能力和推导出的连续力学模型将测试对模拟材料和重熔实验，以及对可用的解析解。在科学和工程中的许多重要的流动现象的结果是复杂的流动行为的密集，泡状颗粒悬浮液之间的流体和固体，有时被称为浆料。涉及泥浆的过程的例子包括火山管道中的岩浆流动，影响火山喷发动力学（爆炸与溢出）和热传递，影响火山灾害和可再生地热能源的评估。其他地球科学应用包括滑坡、泥流和火山泥流，它们也代表了液体、颗粒和（有时）气泡的混合物，对地质灾害和（人为和自然）环境影响的评估有影响。泥浆的特定流动行为在生物和医学过程中也起着重要作用，例如血液流过静脉或地下水中的微生物运输。该项目的工程应用可能包括食品，泡沫，水泥，凝胶和陶瓷加工。这里提出的研究旨在开发一个计算机代码来模拟颗粒和气泡在浆料中的相互作用，在一个非常小的规模，以确定散装物质如何变形和流动，以及它如何进行气体。在小尺度上获得的见解然后被放大到感兴趣的实际空间和时间尺度。这种方法是困难的，但重要的，因为夹杂物（颗粒，气泡）的小尺度相互作用对这些流体的复杂（非牛顿）流动行为有很大的影响，否则经常调用的Navier-Stokes方程通常不能使用。因此，基于其夹杂物性质预测致密浆料的流动行为，有可能对处理这种非标准但经常遇到且重要的流体的科学和工程产生重大影响。此外，该项目还支持博士后研究人员，并通过实验室，本科生和研究生的互动，他们接受数学，计算机，材料和地球物理科学的跨学科培训。预计开发的计算机代码将引起众多科学和工程学科的兴趣。