Influence of tribo-electrification on bulk powder rheology

在涉及颗粒固体的制造过程中，了解和控制粉末材料的特性及其对工艺操作的影响至关重要。粉末处理往往伴随着摩擦带电的巨大潜力，这一现象对处理具有一致性的粉末的能力产生了不利影响。然而，对摩擦带电对粉末行为的影响的了解很少。利兹大学的Ghadiri研究小组开发了许多用于表征摩擦带电的测量技术，最新的发展是围绕使用马尔文Panalytical Morphologi分析系统的弥散单元进行摩擦带电，并配以法拉第笼进行电荷测量。然而，几乎所有可用的方法都是基于分散粉末系统。散装粉末在剪切应变下摩擦带电的评估，因为它发生在粉末流动中，还没有得到广泛的解决。鉴于它与粉末处理中的工业应用直接相关，这是一个值得开发和进一步了解的课题。本项目旨在开发适当的实验工具和相关分析来评估广泛的粉末系统的响应。因此，该项目显然符合CDT的目标，即研究粉末研究领域中材料、工艺和性能之间的关系。目的1.考虑与理解粉末系统摩擦带电有关的各种技术；2.开发适当的技术来表征散装粉末的摩擦带电3。验证各种技术的测量精度和参数空间；4.建立关联颗粒大小、形状和静电电荷的模型，以及这些因素对粉末加工性能的影响。

Understanding and control of powder material properties and their influence on process operations are critical in manufacturing processes involving particulate solids. Powder handing is often accompanied by a significant potential for tribo-electrification, a phenomenon which adversely affects the ability to process powders with consistency. However, understanding of the impact of tribo-electrification on powder behaviour is very poor. The Ghadiri Research Group at the University of Leeds have developed a number of measurement techniques for the characterisation of tribo-electrification, the latest development being around the use of the dispersion unit of the Malvern Panalytical Morphologi analysis system for tribo-electric charging, accompanied by a Faraday cage for charge measurement. However, almost all methods available are based on dispersed powders systems. Assessment of tribo-electrification of bulk powders under shear straining, as it occurs during powder flow, has not been widely addressed. It is a topic worthy of development and further understanding in view of its direct relevance to industrial applications in powder handling.This project seeks to develop appropriate experimental tools and associated analysis to evaluate the response of a wide range powder systems. The project therefore clearly aligns with the aims of the CDT to look at relationships between materials, processes and performance in the field of powder research. Aims1. Consider various techniques relevant to understanding the tribo-electrification of powder systems; 2. Develop appropriate techniques to characterise tribo-electrification of bulk powders3. Validate the measurement accuracy and parameter space for various techniques; 4. Develop models linking particle size, shape and electrostatic charge and the impact these have on powder processability.