Experiments, Simulations and Models of Colliding Particles in a Liquid

美国国家科学基金会-化学运输系统司？微粒多相工艺程序（1415）提案编号：0730284主要研究者：Hunt，Melany附属机构： 加州理工学院 提案标题：液体中颗粒碰撞的实验、模拟和模型本文的工作包括粘性流体中颗粒壁面碰撞和颗粒间碰撞的实验、模拟和模型化。近年来，拉格朗日模型，如离散元模型，已被引入到计算颗粒流在颗粒水平，结合尺寸变化，材料特性，和颗粒间的力。虽然这些模型依赖于简化的碰撞相互作用，建模已成功地应用于一系列的工业和地球物理流程。对于液固两相流，目前还没有一种类似的技术可以广泛应用于泥石流、泥浆和泥沙输运问题。这个建议的重点是研究粒子碰撞在液体中的发展碰撞模型，可以纳入大规模computation.Intellectual优点：拟议的工作包括四个部分，涉及的方法和反弹的粒子到另一个表面的基本理解。所提出的工作包括以下内容：（1）研究碰撞颗粒的接近和反弹中所涉及的力;（2）颗粒和周围流体流动的耦合运动的浸没边界模拟，以及边界条件的引入;（3）浸没颗粒链的实验测量;以及（4）颗粒碰撞引起的流体运动的测量。伴随的实验旨在指导和验证模型预测。该建议侧重于惯性和碰撞效应，并涉及斯托克斯和雷诺数大于1.Broader影响：拉格朗日粒子模型已被广泛用于调查药物和片剂的混合，流动的滑坡，颗粒分离料斗，和运输的农产品。目前，有努力扩展这种拉格朗日技术，包括间隙气体的影响。然而，已经有较少的注意力指向使用该方法来计算液体和固体的流动，大概是由于液体-固体相互作用和润滑力的复杂性。我们提出的计算和实验的努力应该是有益的，在开发计算算法的一系列问题中发现的地球物理和工业flow.An研究工作的一个组成部分是教育学生。在先前和正在进行的研究中，PI非常重视将代表性不足的群体的学生纳入其中，本科生的广泛参与，并在适当时将高中生纳入其中。这些学生有机会撰写技术论文，并在适当的科学会议上介绍研究成果。PI还通过社区和校园项目向当地学校介绍了她的研究。

National Science Foundation - Division of Chemical &Transport Systems ? Particulate & Multiphase Processes Program (1415)Proposal Number: 0730284 Principal Investigators: Hunt, Melany Affiliation: California Institute of Technology Proposal Title: Experiments, Simulations and Models of Colliding Particles in aLiquid The proposed work includes experiments, simulations and modeling of particlewall and particle-particle collisions in a viscous fluid. In recent years, Lagrangian models, such as the discrete element model, have been introduced to compute granular flows at the particle level, incorporating size variations, material properties, and interparticle forces. Although these models rely on simplifications of the collisional interaction, the modeling has been successfully applied to a range of industrial and geophysical flows. For liquid-solid flows, there currently is not a similar technique that can be applied widely to debris flows, slurries, and sediment transport problems. The focus of this proposal is to examine particle collisions in a liquid with an emphasis on developing collisional models that can be incorporated into large scale computations.Intellectual Merit:The proposed work consists of four parts that involve a fundamental understanding of the approach and rebound of a particle to another surface. The proposed work consists of the following: (1) investigation of forces involved in the approach and rebound of colliding particles; (2) immersed-boundary simulations of the coupled motion of the particle and surrounding fluid flow, and the incorporation of the boundary condition; (3) experimental measurements of immersed particle chains; and (4) measurements of the fluid motion resulting from particle collisions. The accompanying experiments are designed to guide and validate the model predictions. This proposal focuses on inertial and collisional effects, and involves Stokes and Reynolds numbers greater than one.Broader Impacts:Lagrangian particle models have been used extensively to investigate mixing of pharmaceuticals and tablets, flows of landslides, particle segregation in hoppers, and transport of agricultural products. Currently, there are efforts to extend this Lagrangian technique to include the effects of an interstitial gas. However, there has been less attention directed to using the method to compute flows of liquids and solids, presumably due to the complexity of the liquid-solid interactions and the lubrication forces. Our proposed computational and experimental efforts should be beneficial in developing computational algorithms for a range of problems found in both geophysical and industrial flows.An integral part of this research work is the education students. In prior and ongoing research, the PI has placed a heavy emphasis on the inclusion of student from underrepresented groups, extensive involvement of undergraduate students, and when appropriate, the inclusion of high school students. These students have the opportunity to author technical papers and to present research findings at appropriate scientific meetings. The PI has also presented her research to local schools through community and campus programs.