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Elaborate Classification of Fine Particles by Modified Type Cyclone and Its Optimization

改进型旋流器细颗粒分级及其优化

基本信息

批准号：
09650831
负责人：
YOSHIDA Hideto
金额：
$ 2.18万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650831/
关键词：
cyclone classification fine particles simulation collection optimization separation efficiency 環境分補効率

项目摘要

Experimental studies were conducted on the classification of fine particles by use of a modified cyclone with movable 50% cut size on a bench scale. The 50% cut size of cyclone changed from 1 to 10 , u m by the change of apex cone height and blow-up flow rate. When the height of apex cone was higher at a constant blow-up flow rate, the 50% cut size increased. The reason for this was due to the fact that a decrease in the effective cross-sectional area near the inlet of the dust box gave rise to the increased average upward fluid velocity.In the case of blow-down, two kinds of different-sized fine particle were obtained simultaneously. When the blow-down flow rate was 5%, collection efficiencies of 4 and 28% were obtained with mean particle diameters 2 and 6 mu m respectively. When both the blow-down method and a movable guide plate at the cyclone inlet were used, particles of average diameter of 1.5 mu m were collected. Although the cyclone diameter was 400 mm, elaborate classification of fine particles was achievable.In order to obtain the information of the high-performance cyclone classifier, three-dimensional numerical simulation and experimental studies were conducted on the fluid flow and particle trajectory in a cyclone classifier with and without blow-down. By use of blow-down method, the overall separation efficiency of a cyclone is higher than the case without blow-down. From the results of simulation, the reason for this is found to be the fact that downward velocity components near the conical wall are stronger in the case of blow-down compared to the case without blow-down.

在实验室条件下，采用可移动50%粒度的改进型旋风分离器进行了细粒分级的实验研究。旋风分离器的50%截面积随顶锥高度和吹气流量的变化从1变到10µm。在一定的吹气流量下，当顶锥高度较高时，50%的切割尺寸增大。这是由于除尘器入口附近的有效截面积减小导致平均上升速度增大所致，在吹扫的情况下，同时获得了两种不同尺寸的细小颗粒。当排污率为5%时，除尘效率分别为4%和28%，平均粒径分别为2和6微米。当旋风分离器入口同时采用排污法和活动导流板时，可收集到平均直径为1.5微米的颗粒。在旋风分离器直径为400 mm的情况下，实现了细微颗粒的精细分级，为了获得高性能旋风分离器的信息，对旋风分离器内流体流动和颗粒运动轨迹进行了三维数值模拟和实验研究。采用排污方式时，旋风分离器的整体分离效率高于无排气的情况。从模拟结果可以看出，这是因为在有排污的情况下，锥形壁面附近的下行速度分量比没有排污的情况下更强。