固液搅拌槽内液相速度的分布

LIQUID VELOCITY DISTRIBUTIONS IN SOLID-LIQUID STIRRED VESSELS

在两个几何相似固 -液搅拌槽内 ,采用双电导探针测定了固体浓度较高的固液体系中液相速度的分布 .固相质量分数从 12 .5 %至 38.2 % (体积分数Cv 从 5 .4 %至 19.8% ) ,搅拌槽直径分别为80 0mm与16 0 0mm ,采用一种高效的长薄叶螺旋桨搅拌器 (CBY)向下泵送操作 .实验研究了固体浓度变化以及搅拌槽放大对液相速度分布的影响 .

Experiments were carried out in cylindrical Plexiglass tanks of 0.8?m and 1.6?m diameter agitated by single down pumping propeller (CBY).A new type of bi-electrode probe was used to measure local,three-dimensional liquid velocities in the solid-liquid system with solid volumetric concentration ( C v) from 5.4% to 19.8%.The effects of solid volumetric concentration and scaling-up on liquid velocity distribution were studied.The down-flow outside a propeller was accelerated and the up-flow near the wall of tank was resisted by particles.The resultant liquid velocities just above the bottom of the tank are also resisted by particles.Outside the agitator radius (2 r/T>D/T ) the mean resultant liquid velocity along radius in jet region ( h/T =0.3) increases about 12% in the small tank and by 45% in the large one with solid volumetric concentration ( C v) of 5.4%.The flow numbers were calculated for a homogeneous fluid and a suspension in the two stirred tanks.