涡轮桨直径对锥盘底搅拌槽固液混合特性影响  

Influence of turbine impeller diameter on solid-liquid mixing characteristics of cone-bottom stirred tank

作　　者：贾慧灵[1,2] 赵静[1] 李梅[2,3] 任保根 

机构地区：[1]内蒙古科技大学机械工程学院,内蒙古包头014010 [2]北京化工大学材料科学与工程学院,北京100029 [3]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《化学工程》2017年第6期62-68,共7页Chemical Engineering(China)

基　　金：教育部创新团队项目(2011CB612203);内蒙古自治区高等学校科学技术研究项目(NJZY14169)

摘　　要：利用CFD技术对锥盘底搅拌槽内的固液两相流混合浓度场进行数值模拟研究,考察了45°圆盘涡轮式搅拌桨直径d对固液混合时间数,单位体积混合能,浓度标准差,湍动能和湍动耗散率,和固相离底悬浮临界转速的影响。研究表明:随着搅拌桨直径的增大,搅拌槽内的流体由轴向流转变为径向流的流型转变高度逐渐减小。桨径比d/D大于0.3时,混合时间数显著减小;d/D小于0.4时,单位体积混合能较小;d/D达到1/3时,单位体积混合能最小。浓度标准差随搅拌桨直径的变化波动较小。d/D小于0.4时,湍动耗散率的增长率较低;d/D大于0.3时,固相离底悬浮临界转速显著减小。从提高混合效率和降低能耗的综合角度考虑,桨径比d/D应控制在0.3—0.4之间。Numerical simulation of concentration field of solid-liquid two-phase flow in stirring tank was carried out with CFD. The influence of 45° disc turbine impeller diameter on mixing time, mixing energy per unit volume, concentration standard deviation, turbulent kinetic energy and turbulent dissipation rate, solid and liquid critical off-bottom suspension speed was analyzed. The result show that with the increasing of paddle diameter, the inversion height of flow changed from axial flow to radial flow in stirred tank decreases. When d/D is more than 0.3, mixing time decreases obviously. When d/D is less than 0.4, the mixing energy per unit volume is small. When d/D reaches 1/3, the mixing energy per unit volume is the smallest. The standard deviation of the concentration fluctuates changed less with the stirring diameter. When d/D is less than 0.4, the growth rate of turbulent dissipation rate is low. Critical suspension speed of solid phase is significantly reduced as d/D is more than 0.3. So the ratio d/D should be controlled between 0.3 and 0.4 in order to improve the mixing efficiency and reduce the energy consumption.

关 键 词：计算流体力学 搅拌桨直径 锥盘底搅拌槽 两相流 数值模拟 

分 类 号：TQ051.72[化学工程]