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

Electric Conduction, Adhesion Forces and Discharge Processes in a Particle-Particle-Contact - Highly Resistive Materials

颗粒-颗粒接触中的导电、粘附力和放电过程 - 高电阻材料

基本信息

批准号：
169555597
负责人：
Professor Dr.-Ing. Ulrich Riebel
金额：
--
依托单位：
Lehrstuhl Mechanische Verfahrenstechnik
依托单位国家：
德国
项目类别：
Priority Programmes
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/169555597?language=en
关键词：
Electric Conduction Adhesion Forces Discharge

项目摘要

In case of electrical conduction across the particle-particle-contacts in highly resistive dust layers, the generation of electrostatic adhesion force is strongly coupled to the mechanisms of electrical transport in the solid. High field strengths lead to a significant increase of adhesive forces. For the electrical resistivity, a pronounced non-ohmic behaviour with strong time effects is observed. Aim of the project is to investigate the underlying mechanisms by experiments and simulations on the microscopic scale. Our previous investigations have shown that the mechanisms of charge transport in highly resistive particle layers correspond to those in electrete materials. During current transport, positive and negative charge carriers are injected into the material, and significant electrostatic space charges are formed. The time effects are explained by the mechanisms of charge injection and by the immobilization of charges in the particle volume. In the contact gaps and pore spaces, charge transport can occur by the mechanisms of thermionic field emission and gas discharge. Even though strong electrostatic adhesion forces are generated on the microscopic level, the macroscopic space charge excess can lead to a mechanical failure of highly resistive dust layers by electrostatic repulsion. In the continuation of the project, the successful measurements on single particle-particle contacts shall be improved and continued. Here, the current uptake and the contact force are measured (time-resolving) as a function of particle diameter, contact gap distance, particle material and applied voltage. The mechanism of charge transport across the contact gap shall be verified by observing the emission of light and gas ions. Within the simulation part of the project, a model incorporating the mechanisms of charge transport in the solid and in the contact gap is being developed. Via local potentials, field strengths, charge carrier densities and current densities, the conduction or discharge mechanisms in the gap and the contact force are to be obtained. Here as well, the appropriate modelling of time effects is an important task.The simulations will be verified using results from the single particle experiments. Finally, we will try to simulate chain-like particle arrangements as a model for macroscopic particle layers. Additionally, experiments on particle layers and on massive layers of (dielectric) materials will be made.

在高电阻粉尘层中的颗粒-颗粒接触之间的导电情况下，静电粘附力的产生与固体中的电传输机制强烈耦合。高场强导致粘附力的显著增加。对于电阻率，观察到具有强烈时间效应的明显非欧姆行为。该项目的目的是通过实验和微观尺度上的模拟来研究潜在的机制。我们以前的研究表明，在高阻粒子层中的电荷传输机制对应于驻极体材料中的电荷传输机制。在电流传输期间，正电荷载流子和负电荷载流子被注入到材料中，并且形成显著的静电空间电荷。的时间效应的电荷注入和固定的电荷在粒子体积的机制来解释。在接触间隙和孔隙空间中，电荷传输可以通过电子场发射和气体放电机制发生。即使在微观水平上产生强的静电粘附力，宏观空间电荷过剩也会通过静电排斥导致高电阻灰尘层的机械故障。在项目的继续中，应改进和继续对单个颗粒-颗粒接触的成功测量。在这里，电流吸收和接触力作为颗粒直径、接触间隙距离、颗粒材料和施加电压的函数被测量（时间分辨）。应通过观察光和气体离子的发射来验证穿过接触间隙的电荷传输机制。在该项目的模拟部分，一个模型，将在固体和接触间隙中的电荷传输机制正在开发中。通过局部电势、场强、载流子密度和电流密度，可以得到差距中的导电或放电机制以及接触力。在这里，时间效应的适当建模也是一项重要任务，模拟将使用单粒子实验的结果进行验证。最后，我们将尝试模拟链状粒子排列作为宏观粒子层的模型。此外，还将进行粒子层和（电介质）材料块状层的实验。