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

The Effects of Electric Double Layer on Freezing and dehydration in Fine Packed Beds with Liquid Content

双电层对含液细填充床冷冻脱水的影响

基本信息

批准号：
17560177
负责人：
AOKI Kazuo
金额：
$ 2.24万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

We have investigated two different phenomena in heat transfer problems relating to electric double layer ; (1) the trapped and swept phenomenon of foreign particles due to freezing of liquid and (2) the dehydration in fine packed beds using the electro-osmotic flow.(1) When water solution involving fine particles freeze, the freezing process can be divided into two cases whether particles are trapped in the freezing layer or particles are swept out from the freezing layer. The trapped and swept phenomenon of particles due to freezing is widely an important problem related to the freezing process of sludge, the concentration technology and the solidification of metal including foreign particles. We have investigated this phenomenon due to freezing for two cases of independent particles and large number of particles existing in water solution. The trapped and swept phenomenon largely depends on the freezing rate, the size of particle and the surface electric charge of particle. Especially, we focused on the effect of the surface electric charge of particle, on this phenomenon using various particles and water solutions. The calculated results for the critical freezing rate were in agreement with the experimental results using various particles.(2) In packed bed composed of fine particles, an electro-osmotic flow is caused by the addition of external electric fields for the effect of the electric double layer formed near the surface of particles. This phenomenon is an important problem related to the dehydration of contaminated sludge, the electro-osmotic pump in microchannel and the drying in packed beds. The electro-osmotic flow in saturated packed bed has been investigated experimentally. It was found that the flow rate depended on the surface charge of particles, the structure of packed bed and the electrical conductivity. The dehydration of the packed bed using the electro-osmotic flow has been investigated experimentally.

我们研究了与双电层相关的传热问题中的两种不同现象；（1）由于液体冻结而产生的外来颗粒的截留和扫掠现象；（2）利用电渗流在细填充床中进行脱水。（1）当含有细颗粒的水溶液冻结时，冻结过程可分为颗粒被截留在冻结层中和颗粒被从冻结层中扫出两种情况。冻结引起的颗粒截留和扫掠现象是与污泥冻结过程、浓缩技术以及包括异物在内的金属凝固有关的广泛重要问题。我们针对水溶液中存在独立颗粒和大量颗粒两种情况，研究了由于冻结而导致的这种现象。俘获和扫掠现象很大程度上取决于冻结速率、颗粒尺寸和颗粒表面电荷。特别是，我们使用各种颗粒和水溶液来研究颗粒表面电荷的影响。临界冻结速率的计算结果与各种颗粒的实验结果一致。(2)在细颗粒组成的填充床中,由于颗粒表面附近形成的双电层的作用,在外加电场的作用下产生电渗流。这种现象是与污染污泥脱水、微通道电渗泵和填充床干燥相关的重要问题。对饱和填充床中的电渗流进行了实验研究。结果发现，流速取决于颗粒的表面电荷、填充床的结构和电导率。已经通过实验研究了使用电渗流的填充床脱水。