涡轮桨直径对锥盘底搅拌槽固液混合特性影响

发布时间：2018-01-28 11:33

本文关键词： 计算流体力学搅拌桨直径锥盘底搅拌槽两相流数值模拟　出处：《化学工程》2017年06期 　论文类型：期刊论文

【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。
[Abstract]:The mixing concentration field of solid-liquid two-phase flow in a conical disk bottom stirred tank was simulated by CFD technique. The mixing time number and unit volume mixing energy of 45 掳disk turbine impeller diameter d to solid-liquid mixing time were investigated. The effects of concentration standard deviation, turbulent kinetic energy and turbulent dissipation rate, and the critical speed of solid phase suspension are investigated. The results show that the impeller diameter increases with the increase of impeller diameter. The height of flow pattern change from axial flow to radial flow decreases gradually. When D / D is greater than 0.3, the mixing time decreases significantly. When D / D is less than 0.4, the mixing energy per unit volume is smaller. When D / D reaches 1/3, the mixing energy per unit volume is the smallest. When the variation of the standard deviation of concentration with the diameter of the impeller is small. D / D is less than 0. 4, the increase rate of turbulent dissipation rate is lower. When D / D is greater than 0.3, the critical speed of solid suspension decreases significantly. In view of increasing mixing efficiency and reducing energy consumption, D / D of propeller diameter ratio should be controlled in the range of 0.3-0.4.
【作者单位】：内蒙古科技大学机械工程学院;北京化工大学材料科学与工程学院;内蒙古科技大学材料与冶金学院;
【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)
【分类号】：TQ051.72
【正文快照】： 3.内蒙古科技大学材料与冶金学院,内蒙古包头014010)固液搅拌技术广泛用于分离、提纯、结晶等工业反应过程[1]。产品的结晶过程常在搅拌槽内完成,需研究如何以最短的混合时间,最少的单位体积混合能获得所需要的混合效果。搅拌桨的安装高度和尺寸对搅拌槽内固液两相的流动状况

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