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GOALI: Population Balance Modeling: Fundamental Closures and Experimental Validation

GOALI：人口平衡建模：基本封闭和实验验证

基本信息

批准号：
1707046
负责人：
Christine Hrenya
金额：
$ 39.85万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1707046&HistoricalAwards=false
关键词：
GOALI Population Balance Modeling Fundamental

项目摘要

In nature, the flow of solid particles in avalanches and landslides can lead to quite devastating effects. In industrial processing, the flow of solid particles is inherent to the production of pharmaceuticals, oil and gas, chemicals, and agricultural products. To avoid comparable adverse effects, such as industrial accidents and lost productivity, it is important to predict and control the flow of these granular systems. However, the flow of solid particles is poorly understood and not easily modeled. Whereas models of liquid flow are a basic tenant of engineering and derived from basic physical principles, current models of solid particle flow rely on adjustable parameters, are empirical, and incorporate a number of gross simplifications. This research project uses computer simulations and state-of-the-art experiments to develop and validate theoretical models of flows of solid particles that are based on measurable quantities. In addition, this work supports the involvement of underrepresented groups, the training of junior researchers and students, and the involvement of students in an industrial-academic research partnership. Results from the project will be communicated to the general public via blog posts and a Twitter account.This project is focusing on the reliable prediction of the mass flow rate of solids when they are fluidized by the upward motion of a flowing gas. Existing empirical correlations for particle entrainment rate constants may vary by many orders of magnitude when applied to the same system. Current models are primarily limited by empiricism and development to a very particular situation. To develop a predictive understanding of fluidized granular systems, this research is deriving a closure for the continuum theory that is based on population and kinetic theory balances. The resulting model for cohesive-particle flows will require only measurable, physical quantities as inputs. The new continuum framework is being applied to the case of humidity-induced agglomeration. Numerical modeling with discrete element method simulations is being combined with non-intrusive shadowgraphy experiments to validate the new theory. A unique aspect of the work is the development of a novel microscopic (particle-particle) cohesion model that drives the closure of the macroscopic (continuum) theory.

在自然界中，固体颗粒在雪崩和山体滑坡中的流动可能会导致相当毁灭性的影响。在工业加工中，固体颗粒的流动是制药、石油和天然气、化学品和农产品生产所固有的。为了避免类似的不利影响，如工业事故和生产力损失，重要的是预测和控制这些颗粒系统的流动。然而，人们对固体颗粒的流动知之甚少，也不容易对其进行建模。液体流动模型是工程学的基本租户，源自基本物理原理，而当前的固体颗粒流动模型依赖于可调参数，是经验性的，并包含了许多粗略的简化。这项研究项目使用计算机模拟和最先进的实验来开发和验证基于可测量量的固体颗粒流动的理论模型。此外，这项工作还支持代表性不足群体的参与、初级研究人员和学生的培训以及学生参与产学研伙伴关系。该项目的结果将通过博客帖子和推特账号向公众公布。该项目的重点是可靠地预测固体在流动气体向上运动时的质量流动率。现有的颗粒夹带速率常数的经验关联式在应用于同一体系时可能会有许多数量级的变化。目前的模型主要受到经验主义和发展到非常特殊的情况的限制。为了发展对流态化颗粒系统的预测性理解，这项研究正在为基于人口和动力学理论平衡的连续统理论推导出一个封闭式。由此产生的粘性粒子流模型将只需要可测量的物理量作为输入。新的连续体框架被应用于湿度诱导团聚的情况。离散元数值模拟与非侵入式阴影实验相结合，验证了新理论的有效性。这项工作的一个独特方面是发展了一种新的微观(粒子-粒子)内聚模型，该模型推动了宏观(连续)理论的闭合。