Particle Migration in Complex Viscous Flows

摘要CTS-0334825 J。McCarthy，U of Escherichburg这一建议的重点是非中性浮力粒子在复杂的非斯托克斯封闭流中的迁移。这个问题，重要的问题，从材料加工到反应堆设计，还没有被研究，无论是计算或实验，我们的知识。所提出的工作的中心假设是，在这些流动中的各种迁移力-离心力和重力浮力;各种惯性升力（包括自旋和不自旋）;和剪切引起的迁移时，多个粒子存在-可以导致各种各样的渐近行为。 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，我们相信现在可以深入了解复杂流动中的颗粒迁移。在这项工作中，我们专注于两个典型的非斯托克斯封闭流：空腔流和混合槽中的非中性浮力颗粒的迁移行为。具体而言，通过计算和实验研究粒子的运动轨迹和渐近位置，最终目的是揭示迁移模式之间的竞争，使控制粒子的渐近行为成为可能。更广泛的影响在于研究与教学的整合、基础设施的建设和伙伴关系的培养。在项目实施过程中，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加这一奋进。同样，一些本科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/验证几种用于模拟复杂流动中颗粒迁移的计算技术来增强基础设施。它将通过促进PI和国家能源技术实验室之间的未来合作来促进伙伴关系。该建议的智力价值在于获得更好的基本理解的迁移力相关的复杂粘性流。在项目完成后，我们将通过（1）建立关于复杂流动中颗粒迁移的有据可查的实验结果（2）验证用于检查这些流动的伪连续体和离散建模工具来获得先进的发现和理解;最后，（3）发展利用这些系统中的竞争效应的方法，以产生一个合理的程序来改变粒子的性质在一个实施例中，流体流可以包括流体特性（尺寸、形状、密度）、流体性质（密度、粘度）和流场/几何形状，使得流内的离散元件迁移到明确限定的预定位置。

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.