Study on the Flow Field around Two Parallel Moving Bubbles and Interaction Between Bubbles Rising in CMC Solutions by PIV

The flow fields surrounding two parallel moving bubbles rising from two identical orifices submerged in non-Newtonian fluid of carboxymethylcellulose （CMC） solution of three different mass concentration were measured experimentally by the use of particle image velocimetry （PIV）. The influences of gas flowrate, solution mass concentration, orifice interval and the angle between two bubble centers line and vertical direction on the flow field surrounding bubbles were discussed respectively by analyzing the velocity vector, velocity contours as well as individual velocity components. The results show that the liquid velocity both in front of two bubbles and behind increases with gas flowrate duo to shear-thinning effect of previous bubbles, whereas decreases with the increase of CMC concentration due to the increase of drag force acting on bubbles. The effect of the orifice interval on the flow field around two moving bubbles becomes gradually obvious as the interval becomes closer. Moreover, two adjacent side-by-side bubbles repulse each other during rising, leading to the practical interval between them increased somewhat above the orifice interval. When the distance between bubbles is less than the orifice interval 10 mm, the interaction between two neighboring bubbles changed from mutual repellence to attraction with the decrease of the angle of the line of linking two bubble centers to the vertical direction.

包围从二个相同的孔升起的二个平行移动水泡的流动领域在 carboxymethylcellulose (CMC ) 的非牛顿的液体沉没了三个不同的团的答案集中被粒子图象 velocimetry (PIV ) 的使用试验性地测量。在流动上的二根水泡中心线和垂直方向之间的煤气的流动率，答案团集中，孔间隔和角度的影响回答包围水泡被分析速度向量，速度轮廓以及个人分别地讨论速度部件。结果证明在二个水泡前面并且在有到砍变瘦的煤气的流动率二部曲的增加后面的液体速度以前的水泡完成，而由于增加随 CMC 集中的增加减少拖对水泡起作用的力量。当间隔变得更靠近，在二个动人的水泡附近的流动地上的孔间隔的效果变得逐渐地明显。而且，二邻近一起，水泡在升起期间互相打退，导致在他们之间的实际间隔在孔间隔上面有点增加了。在水泡之间的距离是什么时候不到孔间隔 l0 公里，在与连接二个水泡的线的角度的减少从相互的抵抗性改变到吸引力的二个附近的水泡之间的相互作用集中到垂直方向。