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.

悬浮液发生在化学、生物学和环境工程的许多技术和非技术过程中，这只是高度多分散、非均质悬浮液的处理在建模和模拟此类过程时发挥主要作用的两个领域。，颗粒通常被认为是球形的，但颗粒很少是完美的球形，根据它们的形状，可能会发生不同的效果，这可能会极大地影响颗粒悬浮液的沉降行为。这只是一个例子。与球体悬浮液不同，纤维可以改变其方向，这会导致沉降速度随浓度增加或降低。数值模拟已被证明是研究许多问题的有效工具。特别是在使用 CFD 和离散元方法耦合的模拟领域，最近开发了处理非球形颗粒的新方法，但是这些方法仅限于简单凸面的模拟。原则上，后一种方法可用于模拟任意形状的粒子，例如凸多面体或由球形粒子组成的粒子，但需要大量球体才能以良好的精度模拟复杂粒子。是对任意形状颗粒的沉降行为的研究，其几何形状不能用简单的解析表达式来描述，在稀释和浓缩悬浮液中。为了实现这一点，将使用一个数值模型，该模型是专门为这此外，任意形状颗粒接触的正确建模方法将被扩展并包含到开发的模拟包中，以允许模拟浓缩悬浮液产生 3D 数据。分辨率在微米范围内的任意形状颗粒的几何形状，将根据有关悬浮液中任意形状颗粒的时间演化的沉降实验来验证模拟。现在可用的模拟平台，将开发新的方法，通过这些方法可以描述悬浮液中任意形状的颗粒的沉降行为。所提出的项目是模拟平台的第一个方法。可以研究真实的、任意形状的颗粒的沉降行为。