权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Analysis and modelling the coating of solid particles

固体颗粒涂层的分析和建模

基本信息

批准号：
336370664
负责人：
Professor Dr.-Ing. Martin Sommerfeld
金额：
--
依托单位：
Institut für Verfahrenstechnik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/336370664?language=en
关键词：
Analysis modelling coating solid particles

项目摘要

In the frame of the research project it is planned to analyse the fundamentals and to derive models for the collision of droplets with larger solid particles and their coating for Euler/Lagrange calculations. The elementary process of collisions between droplets and larger solid particles will be analysed experimentally using imaging techniques. For that purpose a droplet chain will be produced into which solid particles are shot with defined velocity and frequency. As a result of the collision of droplets with larger particles one may observe bouncing, deposition or disintegration. The collision event will be visualised using high-speed cameras and illumination by LED-arrays and a laser. The results will be analysed by image processing. For all the relevant parameters of influence it is first required to determine the outcome of the collision and summarise them with respect to the important non-dimensional numbers, e.g. Ohnesorge-number and impact Reynolds-number. The considered parameters of influence are the size ratio (droplet/particle), droplet liquid properties (viscosity and surface tension), particle properties (temperature and surface roughness), impact velocity and impact location of the droplet on the particle surface (i.e. central and lateral impacts). As mentioned before, the droplets are smaller than the particles and the liquid is wetting. All these effects need to be considered for deriving physically-based boundaries between the collision outcomes using the relevant non-dimensional numbers. For the regime splashing or partial deposition the size distribution of the droplet fragments also will be analysed and modelled.The next step is the experimental determination of the dimensions of the final liquid film on the particles, including film thickness and lateral dimension of the film. For that purpose the droplet liquid will be doped with fluorescing dye in order to allow a better distinction from the image of the particle. For the development of the coating model with respect to the impact conditions and the relevant non-dimensional numbers, physically based correlations shall be developed.In addition, for analyzing the collision outcomes, theoretical studies will be conducted based on an energy balance. The liquid film formation on the particle will be studied based on film theory.The developed coating model, which considers a broad range of parameters and also for the first time lateral impact, will be derived for being used in the frame of Lagrangian calculations of technical coating processes.

在研究项目的框架内，计划分析基本原理，并推导出液滴与较大固体颗粒碰撞及其涂层的欧拉/拉格朗日计算模型。液滴与较大固体颗粒碰撞的基本过程将利用成像技术进行实验分析。为此目的，将产生一个液滴链，其中固体颗粒以规定的速度和频率射入。由于液滴与较大的颗粒碰撞，人们可以观察到弹跳、沉积或解体。碰撞事件将使用高速摄像机和led阵列和激光照明进行可视化。结果将通过图像处理进行分析。对于影响的所有相关参数，首先需要确定碰撞的结果，并将它们与重要的非量纲数（如奥内索尔数和撞击雷诺数）进行总结。考虑的影响参数包括尺寸比（液滴/颗粒）、液滴液体特性（粘度和表面张力）、颗粒特性（温度和表面粗糙度）、撞击速度和液滴在颗粒表面的撞击位置（即中心和侧向撞击）。如前所述，液滴比颗粒小，液体是湿润的。在使用相关的无量纲数推导碰撞结果之间的物理边界时，需要考虑所有这些影响。对于飞溅或部分沉积的状态，液滴碎片的尺寸分布也将进行分析和建模。下一步是实验确定最终液体膜在颗粒上的尺寸，包括膜厚度和膜的横向尺寸。为此，液滴液体将掺杂荧光染料，以便与颗粒图像更好地区分。针对冲击条件和相关的无量纲数建立涂层模型时，应建立基于物理的相关性。此外，为了分析碰撞结果，将基于能量平衡进行理论研究。本文将基于膜理论对颗粒表面液膜的形成进行研究。开发的涂层模型，考虑了广泛的参数范围，也是第一次横向冲击，将被导出用于技术涂层过程的拉格朗日计算框架。