Suspension Dynamics with Inertia: Combined Discrete-Particle Simulation and Constitutive Modeling Investigations

惯性悬架动力学：离散粒子模拟与本构建模研究相结合

• 批准号: 0853720
• 负责人: Jeffrey Morris
• 金额: $ 30万
• 依托单位: CUNY City College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0853720&HistoricalAwards=false
• 关键词: Suspension; Dynamics; Inertia; Combined; Discrete

0853720MorrisThis project addresses flow of suspensions of rigid particles with inertia at the particle scale. Inertia on the particle scale is defined in terms of the Reynolds number based on shear rate, particle radius and kinematic viscosity. Significant particle-scale inertia implies Reynolds number greater than unity. For small particles, this usually implies larger inertia at the macroscopic scale. Consequently, inertial behavior on multiple scales must be considered. Based on the PI's prior simulations verified against experiment and established simulations, the focus of this study is on simulation of particle-laden flows at finite Reynolds numbers, exploring motions of individual particles as well as particle suspensions. The simulations use the PI's recent developments in the lattice-Boltzmann technique, implemented in a parallel computational algorithm. A number of basic flows will be simulated, including periodic simple shear and pressure-driven flow in conduits, all under a range of finite-Reynolds number conditions with varying particle volume fraction. Flow through conduits showing migrations leading to pronounced accumulation at certain locations have been previously observed. Determination of effective properties of suspensions and modeling of their bulk flow is essential to engineering application of these mixtures. Using statistical analysis of the stress and hydrodynamic diffusivity, a continuum model for suspension flow will be developed. Model predictions will be compared against more complex flows, both from simulations and from experiments. The investigation of bulk suspensions is basic to a wide range of applications involving such materials as inks, coatings and cement as well as many naturally occurring flows. By developing discrete-particle understanding which may be used by theorists and modelers, and developing a continuum description directly from the results, this investigation provides guidance and direction on two fronts. Suspension dynamics is a complex topic, involving physics, mathematics and engineering and thus provides excellent training ground for doctoral and undergraduate research students. The project is designed to involve graduate and undergraduate researchers at one of the most diverse research university settings in the world, the City College of New York. Through collaborations with different universities, laboratories, and industries, young researchers will gain exposure to disciplines from biomedical diagnostics (cell sorting) to the delivery of ceramic precursors and cement. The research results will aid in developing a module in an introductory course using hydrodynamic effects for sorting in microfluidic devices.

0853720莫里斯这个项目解决了在颗粒尺度上具有惯性的刚性颗粒悬浮液的流动。颗粒尺度上的惯性是根据剪切速率、颗粒半径和运动粘度的雷诺数来定义的。显著的颗粒尺度惯性意味着雷诺数大于1。对于小颗粒，这通常意味着在宏观尺度上有更大的惯性。因此，必须考虑多尺度上的惯性行为。基于PI先前的模拟验证实验和建立的模拟，本研究的重点是模拟有限雷诺数下的颗粒流，探索单个颗粒的运动以及颗粒悬浮液。模拟使用PI的晶格玻尔兹曼技术的最新发展，在并行计算算法中实现。将模拟一些基本的流动，包括管道中的周期性简单剪切和压力驱动流动，所有这些都是在有限雷诺数条件下，具有不同的颗粒体积分数。先前已经观察到通过导管的流动显示迁移导致在某些位置的显著积聚。悬浮液有效性质的确定及其整体流动模型的建立是这类混合物工程应用的基础。利用应力和水动力扩散系数的统计分析，将建立悬浮流的连续模型。模型预测将与来自模拟和实验的更复杂的流动进行比较。散装悬浮液的研究是基础，涉及广泛的应用，如油墨，涂料和水泥等材料，以及许多自然发生的流动。 通过发展离散粒子的理解，这可能是由理论家和建模者使用，并直接从结果开发一个连续描述，这项调查提供了两个方面的指导和方向。悬架动力学是一个复杂的课题，涉及物理，数学和工程，因此为博士和本科研究生提供了良好的培训基础。该项目旨在让世界上最多样化的研究型大学之一-纽约城市学院的研究生和本科生研究人员参与。通过与不同的大学，实验室和行业的合作，年轻的研究人员将接触到从生物医学诊断（细胞分选）到陶瓷前体和水泥输送的学科。研究结果将有助于在介绍性课程中开发一个模块，使用流体动力学效应在微流体设备中进行分选。