Investigation of the settling behavior of arbitrarily shaped particles in diluted and concentrated suspensions

研究稀释和浓缩悬浮液中任意形状颗粒的沉降行为

基本信息

批准号：
278893567
负责人：
Professor Dr.-Ing. Hermann Nirschl
金额：
--
依托单位：
Institut für Angewandte und Numerische Mathematik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/278893567?language=en
关键词：
Investigation settling behavior arbitrarily shaped

项目摘要

Suspensions occur in many technical and non-technical processes in chemistry, biology and in environmental engineering. Waste water treatment and ore processing are only two fields in which the treatment of highly polydisperse, heterogeneous suspensions plays a major role. When modelling and simulating such processes, particles are usually assumed to be spherical. But particles are seldom perfectly spherical. Depending on their shape, different effects can occur, which can influence the settling behaviour of a system of particles immensely. Suspensions of fibres are just one example. During settling, fibres can change their orientation. Unlike in suspensions of spheres, this results in a concentration dependant increase or decrease of the settling velocity.Numerical simulations have proven to be an effective tool for the investigation of a number of problems in process engineering. Especially in the field of simulations using a coupling of CFD and the discrete-element method, recently new approaches for the treatment of non-spherical particles have been developed. However, these approaches are limited to the simulation of simple convex geometries, such as convex polyhedrons, or particles composed of spherical particles. In principal the latter method can be used to simulate arbitrarily shaped particles. But a high number of spheres is necessary to model complex particles with good accuracy. The aim of the proposed project is the investigation of the settling behaviour of arbitrarily shaped particles, whose geometry cannot be described by simple analytical expressions, in diluted as well as in concentrated suspensions.In order to achieve this, a numerical model will be used, which has specifically been developed for the simulation of the movement of arbitrarily shaped geometries. Furthermore, approaches for the correct modelling of the contact of arbitrarily shaped particles will be extended and included into the developed simulation package, to allow for the simulation of concentrated suspensions. µ-CT measurements yield 3D data of the geometry of arbitrarily shaped particles with a resolution in the range of microns. Using data from such measurements, the simulation will be validated against sedimentation experiments regarding the time evolution of arbitrarily shaped particles in a suspension. Based on extensive numerical experiments, conducted with the now available simulation platform, new approaches will be developed, with which the settling behaviour of arbitrarily shaped particles in suspensions can be described. These approaches shall only depend on a chosen set of parameters. The proposed project is a first approach towards a simulation platform, with which the settling behaviour of real, arbitrarily shaped particles can be investigated.

悬浮液在化学，生物学和环境工程中的许多技术和非技术过程中发生。废水处理和矿石加工只是两个领域，其中高度分散，异质悬浮液的处理起着主要作用。在建模和模拟此类过程时，通常假定粒子是球形的。但是粒子很少是完美的球形。根据它们的形状，可能会发生不同的影响，这可能会极大地影响颗粒系统的沉降行为。纤维的悬浮液只是一个例子。在设置过程中，纤维可以改变其方向。与球体的悬浮液不同，这会导致集中度取决于设置速度的增加或减小。事实证明，数量模拟是在过程工程中投资许多问题的有效工具。尤其是在模拟领域使用CFD耦合和离职元素方法的耦合，最近对非元素进行了新的处理方法。但是，这些方法仅限于模拟简单的凸几何形状，例如凸多面体或由球形颗粒组成的颗粒。在原理中，后一种方法可用于模拟任意形状的颗粒。但是，需要大量的球体才能以良好的精度对复杂粒子进行建模。拟议项目的目的是研究任意形状的颗粒的设定行为，其几何形状无法通过简单的分析表达式描述，并在稀释液中和浓缩液中悬挂。为了实现此目的，将使用一个数值模型，该模型是专门为任意形状的几何形状运动的模拟而专门开发的。此外，将扩展并包含在开发的仿真软件包中的任意形状颗粒接触的正确建模的方法，以允许浓缩悬浮液的模拟。 µ-CT测量结果产生了以微米范围分辨率的任意形状颗粒几何形状的3D数据。使用来自此类测量结果的数据，将对悬浮液中任意形状的颗粒的时间演变进行沉积实验进行验证。基于现在使用现在可用的仿真平台进行的广泛数值实验，将开发新的方法，并可以描述悬浮液中任意形状的粒子的设置行为。这些方法仅取决于选定的一组参数。拟议的项目是用于模拟平台的第一种方法，可以研究真实，任意形状的粒子的设置行为。