偏心搅拌的流动、悬浮和混合特性

发布时间：2018-04-05 20:43

本文选题：偏心搅拌　切入点：漩涡运动轨迹　出处：《过程工程学报》2017年01期

【摘要】：在直径476 mm的平底圆柱形搅拌槽内,研究了CBY型搅拌桨偏心搅拌的漩涡运动轨迹、漩涡深度规律、上浮颗粒均匀下拉转速、混合时间等特性与偏心率的关系.结果表明,偏心率约为0.45时,漩涡中心分别随偏心率增加作线性与弧线运动,运动轨迹满足一定规律.漩涡深度受偏心率影响远大于转速与物料粘度.偏心率对液位下降率的影响程度是转速的1.9倍,是物料粘度的4.4倍.漩涡深度随偏心率增大而减小,并满足一定线性规律.直径4 mm的聚氯乙烯颗粒均匀下拉转速随偏心率增加先减小后增大,最低值时偏心率为0.4~0.5.液位由0.6T上升到1.0T(T为搅拌槽内径),最佳偏心率转速增加了20.3%,搅拌功耗增大.加装单一挡板改变槽内液体流场,漩涡消失,相同加料位置全挡板混合时间较无挡板时缩短66.9%,混合效果明显增强.
[Abstract]:In a cylindrical tank with a flat bottom of 476mm in diameter, the relationship between eccentricity and swirl trajectory, swirl depth, uniform pull-down speed of floating particles, mixing time and other characteristics of eccentric stirring of CBY type agitator is studied.The results show that when the eccentricity is about 0.45, the vortex center moves linearly and arc with the increase of eccentricity respectively, and the trajectory of the vortex satisfies certain rules.The influence of eccentricity on the depth of swirl is much greater than that of rotational speed and material viscosity.The effect of eccentricity on the drop rate of liquid level is 1.9 times of rotational speed and 4.4 times of material viscosity.The vortex depth decreases with the increase of eccentricity and satisfies a certain linear rule.The uniform pull-down speed of 4 mm diameter PVC particles decreases first and then increases with the increase of eccentricity, and the eccentricity rate is 0.4m 0.5 at the lowest value.When the liquid level rises from 0.6 T to 1.0T(T as the inner diameter of the mixing tank, the optimal eccentricity speed increases by 20.3 and the power consumption increases.When a single baffle is installed to change the liquid flow field in the tank, the swirl disappears, and the mixing time of the whole baffle at the same feeding position is reduced by 66.9% compared with that without the baffle, and the mixing effect is obviously enhanced.
【作者单位】：北京化工大学化学工程学院;
【基金】：国家自然科学基金资助项目(编号:21376016;21506005)
【分类号】：TQ027

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