Particle Migration in Complex Viscous Flows

复杂粘性流中的粒子迁移

• 批准号: 0334825
• 负责人: Joseph McCarthy
• 金额: $ 15万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0334825&HistoricalAwards=false
• 关键词: Particle; Migration; Complex; Viscous; Flows

AbstractCTS-0334825J. McCarthy, U of PittsburghThis proposal is focused on the migration of non-neutrally bouyant particles in complexnon-Stokesian closed flows. This problem, important to issues ranging from materials processing to reactor design, has not been studied either computationally or experimentally, to our knowledge. The central hypothesis of the proposed work is that in these flows the variety of migration forces -- centrifugal and gravitational buoyancy; a variety of inertial lift forces (both with spin and without); and shear-induced migration when multiple particles are present -- can lead to a rich variety of asymptotic behavior. Furthermore, with recent advances in both experimental flow visualization as well as multi-phase Computational Fluid Dynamics (CFD), we believe that strong insight into particle migration in complex flows is now possible. In this work, we focus on the migration behavior of non-neutrally buoyant particles in two prototypical non-Stokesian closed flows: a cavity flow and a mixing tank. Specifically, the research will examine the trajectories and asymptotic locations of particles both computationally and experimentally, with the ultimate aim of uncovering the competition between migration modes such that control of asymptotic particle behavior may be possible.The broader impact of the work lies in integration of research and teaching, infrastructure development, and the fostering of partnerships. During the course of the project training will be provided for one full-time graduate student. Every effort will be made to recruit students from underrepresented groups to participate in this endeavor. Similarly, several undergraduate researchers will be involved in the form of an independent study (thus integrating research and teaching without requiring additional budgeted funds). The proposed work will enhance infrastructure through the generation of both the experimental data (as a metric of comparison for future work) as well as by comparing/validating several computational techniques for modeling particle migration in complex flows. It will foster partnerships by enabling future collaborative work between the PI and the National Energy Technology Laboratory. The intellectual merit of the proposal lies in gaining a better fundamental understanding of the migration forces relevant in complex viscous flows. At the completion of the project we will have advanced discovery and understanding through (1) establishing well-documented experimental results on particle migration in complex flows (2) validating pseudo-continuum and discrete modeling tools for examining these flows; and ultimately, (3) developing methodologies which exploit competing effects within these systems to yielda rational procedure for varying particle properties (size, shape, density), fluid properties (density, viscosity), and flow field/geometry such that the discrete elements within a flow migrate to well-defined predetermined positions.

abstractcts - 0334825 j。McCarthy， U of pittsburgh这一提议的重点是在复杂的非斯托克封闭流动中非中性浮力颗粒的迁移。据我们所知，这个问题对从材料处理到反应堆设计等问题都很重要，但无论是计算还是实验都没有研究过。提出的工作的中心假设是，在这些流动中，各种迁移力——离心力和重力浮力；各种惯性升力（包括旋转和不旋转）；当存在多个粒子时，剪切诱导的迁移会导致丰富多样的渐近行为。此外，随着实验流动可视化和多相计算流体动力学（CFD）的最新进展，我们相信对复杂流动中颗粒迁移的深入了解现在是可能的。在这项工作中，我们重点研究了非中性浮力颗粒在两种典型的非斯托克封闭流动中的迁移行为：空腔流动和混合槽。具体来说，该研究将通过计算和实验来检查粒子的轨迹和渐近位置，最终目的是揭示迁移模式之间的竞争，从而可能控制粒子的渐近行为。这项工作的更广泛影响在于整合研究与教学、发展基础设施和促进伙伴关系。在项目过程中，将为一名全日制研究生提供培训。将尽一切努力从代表性不足的群体中招募学生参与这项努力。同样，一些本科生研究人员将以独立研究的形式参与（从而将研究和教学结合起来，而不需要额外的预算资金）。拟议的工作将通过生成实验数据（作为未来工作的比较指标）以及通过比较/验证几种模拟复杂流动中的颗粒迁移的计算技术来增强基础设施。它将促进PI和国家能源技术实验室之间未来的合作，从而促进伙伴关系。该建议的智力价值在于对复杂粘性流动中相关的迁移力有了更好的基本理解。在项目完成后，我们将通过(1)建立复杂流动中颗粒迁移的充分记录的实验结果(2)验证用于检查这些流动的伪连续统和离散建模工具，获得先进的发现和理解；最终，(3)开发方法，利用这些系统内的竞争效应，为不同的颗粒特性（大小、形状、密度）、流体特性（密度、粘度）和流场/几何形状提供合理的程序，从而使流动中的离散元素迁移到定义良好的预定位置。