单层钢丝柔性桨强化搅拌槽中流体混沌混合行为

发布时间：2018-03-18 06:50

本文选题：钢丝　切入点：柔性桨　出处：《化工学报》2017年12期 　论文类型：期刊论文

【摘要】：实验运用扭矩传感器测量搅拌功率特性,Matlab软件编程计算最大Lyapunov指数(LE_(max)),流场可视化技术观测流体混合状态。研究了桨叶类型、桨叶离底距离、柔性钢丝长度、柔性钢丝直径对混合效率数(Ce)、LE_(max)的影响。结果表明:单层钢丝柔性桨通过刚-柔-流耦合作用,改变流场结构和能量耗散方式,提高了流体混沌混合程度,实现了流体的高效节能混合;当转速为120 r·min-1时,与传统刚性桨相比,单层钢丝柔性桨使流体Ce减小了87.4%,LE_(max)增大了53.2%,与单层钢丝刚性桨相比,单层钢丝柔性桨使流体Ce减小了43.8%,LE_(max)增大了10.8%。另外,当搅拌转速相同时,柔性钢丝越长,越有利于流体混沌混合,但其功耗也会随之明显增加;当柔性钢丝直径为0.8 mm,桨叶离底距离为0.25T(T为搅拌槽内径)时,各个转速对应的Ce小于其他情况、LE_(max)大于其他情况,流体达到相对最佳混沌混合状态。
[Abstract]:The torque sensor is used to measure the mixing power characteristics. The maximum Lyapunov exponent is calculated by Matlab software. The flow field visualization technique is used to observe the mixing state of the fluid. The blade type, blade bottom distance and flexible steel wire length are studied. The effect of the diameter of flexible steel wire on the mixing efficiency is discussed. The results show that the single layer steel wire flexible propeller changes the flow field structure and energy dissipation mode through the rigid-flexible flow coupling, and improves the chaotic mixing degree of the fluid. When the rotational speed is 120r 路min-1, compared with the traditional rigid propeller, the single layer steel wire flexible propeller reduces the fluid ce by 87.4% and increases 53.2% compared with the single layer steel wire rigid propeller. The single layer steel wire flexible propeller reduces the fluid ce by 43.8% and increases 10.8%. In addition, when the stirring speed is the same, the longer the flexible steel wire is, the more favorable the fluid chaotic mixing is, but the power consumption also increases obviously. When the diameter of the flexible steel wire is 0.8 mm and the blade distance from the bottom is 0.25 T as the inner diameter of the stirring tank, the ce corresponding to each rotational speed is smaller than that of the other cases.
【作者单位】：重庆大学化学化工学院;清华大学化学工程系;
【基金】：国家自然科学基金项目(21576033);国家自然科学基金重点项目(21636004) 重庆市社会民生科技创新专项项目(cstc2015shmszx100024) 中央高校基本科研业务费专项项目(106112017CDJQJ228808)~~
【分类号】：TQ027

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