MDC: Direct Simulation of the Motion of Particles in Flowing Liquids

MDC：流动液体中颗粒运动的直接模拟

• 批准号: 9527123
• 负责人: Daniel Joseph
• 金额: $ 166.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-10-01 至 1999-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527123&HistoricalAwards=false
• 关键词: MDC; Direct; Simulation; Motion; Particles

9527123 Joseph This project will develop highly efficient methods for computing the three-dimensional motion of large number of particles in solid-liquid flows, under the action of the hydrodynamic forces and torques exerted by the suspending fluid, and use these methods to elucidate the fundamental dynamics of particulate flows and solve problems of engineering interest. The goal is to develop high-performance, state-of -the-art software packages called particle movers, capable of simulating the motion of thousands of particles in 2-D and hundreds in 3-D domains, in both Newtonian fluids, governed by the Navier-Strokes equations, and in several popular models of viscoelastic fluids. Such simulations will be extremely computationally intensive. It is therefor imperative to develop the most efficient possible computational schemes, and to implement them on parallel machines, using state-of-the-art parallel algorithms. The project will develop two different computational schemes for simulating solid-liquid flows on parallel computers. The first is a generalization of the standard Galerkin finite element method in which both the fluid and particle equations of motion are incorporated into a single variational equation, containing both fluid and particle velocities as primitive unknowns. In the second approach, an embedding method, the fluid flow is computed as if the space occupied by the particles were filled with fluid. The no-slip boundary condition of the particle boundaries is enforced as a constraint using Lagrange multipliers. This allows a fixed grid to be used, eliminating the need for remeshing, a definite advantage in parallel implementations. The new schemes will be used to study the microstructural (pair interaction) effects which produce clusters and anisotropic structures in particulate flows, to produce statistical analyses of particulate flows (mean values, fluctuation levels and spectral properties), to derive engineering correlations of the kind usually obtained from expe riments, and to provide clues and closure data for the development of two-phase flow models and a standard against which to judge the performance of such models. They will also be used to solve practical problems of industrial interest such as sedimentation, fluidization an slurry transport of solid particles in Newtonian and viscoelastic fluids.

9527123约瑟夫本项目将开发高效的方法来计算固体-液体流动中大量颗粒的三维运动，在悬浮流体施加的水动力和扭矩的作用下，并使用这些方法来阐明颗粒流的基本动力学和解决工程问题。 目标是开发高性能，最先进的软件包称为粒子移动器，能够模拟成千上万的粒子在2-D和数百个在3-D域中的运动，在牛顿流体中，由Navier-Strokes方程控制，并在几个流行的粘弹性流体模型中。 这样的模拟将是非常计算密集型的。 因此，当务之急是开发最有效的可能的计算方案，并实现它们的并行机，使用国家的最先进的并行算法。该项目将开发两种不同的计算方案，用于在并行计算机上模拟固体-液体流动。 第一种是标准Galerkin有限元法的推广，其中流体和粒子的运动方程被纳入一个单一的变分方程，包含流体和粒子的速度作为原始未知数。在第二种方法中，即嵌入方法，流体流的计算就好像粒子所占据的空间充满了流体一样。 颗粒边界的无滑移边界条件作为约束使用拉格朗日乘子。 这允许使用固定网格，无需重新划分网格，这在并行实现中具有明显的优势。新方案将用于研究微结构（对相互作用）效应，在颗粒流中产生团簇和各向异性结构，以产生颗粒流的统计分析（平均值、波动水平和光谱特性），以推导出通常从实验中获得的工程相关性，为两相流模型的发展提供线索和闭合数据，并为判断两相流模型的性能提供标准。 它们也将被用来解决工业上的实际问题，如沉降、流化和固体颗粒在牛顿流体和粘弹性流体中的浆液输送。