化工学报

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错位刚柔桨强化搅拌槽内流体混合实验及数值模拟

刘作华1,3, 魏红军1,3, 熊黠1,3, 陶长元1,3, 王运东2, 程芳琴4   

  1. 1 重庆大学化学化工学院, 重庆 400044;
    2 清华大学化学工程系, 北京 100084;
    3 煤矿灾害动力学与控制国家重点实验室, 重庆大学, 重庆, 400044;
    4 山西大学资源与环境工程研究所, 山西 太原, 030006
  • 收稿日期:2020-03-24 修回日期:2020-04-26 出版日期:2023-04-17 发布日期:2020-05-25
  • 通讯作者: 刘作华(1973-),男,博士,教授,liuzuohua@cqu.edu.cn E-mail:liuzuohua@cqu.edu.cn
  • 作者简介:刘作华(1973-),男,博士,教授,liuzuohua@cqu.edu.cn
  • 基金资助:
    国家重点研发计划项目(2017YFB0603105);国家自然科学基金项目(21636004);重庆市教委科学技术研究计划项目重点项目(KJZD-M201900101);重庆市技术创新与应用示范专项产业类重点研发项目(cstc2018jszx-cyzdX0085)

Experiment and numerical simulation of chaotic mixing performance enhanced by perturbed rigid-flexible impeller in stirred tank

LIU Zuohua1,3, WEI Hongjun1,3, XIONG Xia1,3, TAO Changyuan1,3, WANG Yundong2, CHENG Fangqin4   

  1. 1 School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China;
    2 Department of Chemical Engineering, Tsinghua University, Beijing 100084, China;
    3 State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China;
    4 Institute of Resources and Environment Engineering, Shanxi University, Taiyuan 030006, Shanxi, China
  • Received:2020-03-24 Revised:2020-04-26 Online:2023-04-17 Published:2020-05-25

摘要: 为消除搅拌反应器中混合隔离区,对标准刚性桨(R-RT)、错位刚性桨(PR-RT)和错位刚柔桨(PRF-RT)三种桨叶体系的流体混沌特性参数、流场结构以及流体运动速度进行了探讨。采用Matlab软件编程计算最大Lyapunov指数(LLE)和多尺度熵(MSE),通过计算流体力学研究了三种桨叶体系流场结构和流体运动速度的差异。实验及计算结果表明,错位刚柔桨通过柔性桨叶的随机扰动破坏了隔离区介稳态流场边界,较大程度的消除了混合隔离区。PRF-RT桨的LLE相比于R-RT和PR-RT桨分别提高了13.29%和7.25%,MSE也较PR-RT和R-RT桨大;PRF-RT桨增强了流场不稳定性,形成了不对称性流场结构,减少了隔离区分布范围;PRF-RT桨强化桨叶能量耗散,提高了搅拌槽底部、顶部液面以及搅拌槽壁区域流体运动速度,减小了流体混合时间。

关键词: 错位刚柔桨, 最大Lyapunov指数, 多尺度熵, 数值模拟

Abstract: In order to eliminate the isolated mixing regions in the stirred tank, factors associated with chaotic mixing performance were studied, including flow field structure and fluid velocity of rigid RT impeller (R-RT), perturbed rigid RT impeller (PR-RT) and perturbed rigid-flexible RT impeller (PRF-RT). The largest Lyapunov exponents and the multi-scale entropy were computed by Matlab software. The differences of flow field structure and fluid velocity in three impeller systems were discussed by computational fluid dynamics. The experimental and computational results showed that perturbed rigid-flexible RT impeller could destroy the boundary of the mesostatic flow field in the isolated mixing regions and the symmetry flow in the process of fluid mixing through the random disturbance of the flexible blade, eliminating the isolated mixing regions. At 90 r/min, the LLE of the perturbed rigid-flexible RT impeller is larger than that of rigid RT impeller and perturbed rigid RT impeller. The LLE of the rigid-flexible RT impeller compared with the rigid RT impeller and perturbed rigid RT impeller increases 13.29% and 7.25% respectively and the MSE of the perturbed rigid-flexible RT impeller is also larger than that of rigid RT impeller and perturbed rigid RT impeller. The perturbed rigid-flexible RT impeller enhances the flow field instability, forms an asymmetric flow field structure, and reduces the distribution range of isolated mixing regions. The perturbed rigid-flexible RT impeller enhances the energy dissipation of the blade, improves the fluid velocity at the bottom and top of the tank and the wall of the tank, and reduces the mixing time.

Key words: perturbed rigid-flexible impeller, largest Lyapunov exponents, multi-scale entropy, numerical simulation

中图分类号: 

  • TQ027.2
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