School of Chemical & Environment Engineering,China University of Mining & Technology(Beijing),Beijing　 100083,China

为了研究絮团的形态对絮团与气泡碰撞及吸附的影响,设计了图像分析系统,拍摄了絮团与气泡接触过程中的视频文件并从中提取含有絮团位置及形态特征的静态帧。使用Image Pro Plus 6.0根据絮团的粒径对絮团进行了粒度级的划分,使用统计学的方法,对每个粒度级的絮团与气泡的碰撞及吸附效率进行了分析及计算,发现碰撞效率随絮团粒径的增加而增长,吸附效率先随着粒径的增加而增长但是在絮团粒径为200μm左右时出现转折,开始下降。利用Matlab位置提取程序对絮团运动过程中位置信息进行获取,根据Stokes沉降原理,计算絮团密度,发现絮团的密度随着粒径的规律性变化,在粒径为170μm时密度最大。认为絮团粒径对碰撞效率起主导作用,絮团密度对吸附效率起主导作用。此外,通过观测絮团与气泡接触过程发现,结构密实的絮团自与气泡发生接触后接触点恒定,而结构疏松的絮团与气泡接触后普遍存在旋转的现象,接触点的变化,导致结构疏松的絮团极易从气泡上脱落,吸附效率低。

In order to study the effect of floccule morphological characteristics on the collision and attachment between floccule and bubble,an image analysis system was designed. The video files of the contact motions between floccule and bubble were captured and the static frames with the position and morphological characteristics messages were ex- tracted. According to the particle sizes of floccules,the Image Pro Plus 6. 0 was used to divide the particle size frac- tions. The statistical method was used to calculate and analyze the collision and attachment probabilities between the floccule and bubble of each particle size fraction. The results showed that the collision efficiency increased with the floccule diameter,the attachment efficiency increased with the increase of floccule diameter,but decreased when the floccule diameter grew to 200 μm. The position extraction procedure of Matlab was used to obtain the location informa- tion of the floccule in the movement process,and calculate the floccule density based on the Stokes settlement princi- ple. The results showed that the floccule density had a regularity change with the floccule diameter,when the floccule diameter was 170 μm,the floccule density had the maximum value. The results showed that the diameter of floccule had a significant influence on the collision efficiency and the floccule density played a major role on the attachment efficiency. In addition,through the observation of the characteristics of the floccule movements,it was found that the con- tact point between the compactness structure floccule and the bubble was changeless,and the contact point between the loose structure floccule and the bubble was changeable. The loose structure floccule occurred a rotation,that meant the loose structure floccule was easy to fall off from the bubble and was hard to attach on bubble,therefore,the attach- ment efficiency was low.

国家自然科学基金资助项目(51474211)；

Zhao Jing,Fu Xiaoheng,Song Guoyang,et al. Effect of floccule morphological characteristics on the collision and attachment between floc- cule and bubble[J]. Journal of China Coal Society,2017,42(3):738-744.