化工学报 ›› 2020, Vol. 71 ›› Issue (S1): 227-235.DOI: 10.11949/0438-1157.20191315

• 流体力学与传递现象 • 上一篇    下一篇

不同推进式桨叶对搅拌反应器内气液两相混合特性的影响

黎义斌1,2(),宋亚娟1,歹晓晖1,李正贵3   

  1. 1.兰州理工大学能源与动力工程学院,甘肃 兰州 730050
    2.甘肃省流体机械及系统重点实验室,甘肃 兰州 730050
    3.西华大学流体及动力机械教育部重点实验室,四川 成都 610039
  • 收稿日期:2019-11-04 修回日期:2020-01-07 出版日期:2020-04-25 发布日期:2020-04-25
  • 通讯作者: 黎义斌
  • 作者简介:黎义斌(1977—),男,博士,副教授,liyibin58@163.com
  • 基金资助:
    西华大学流体及动力机械教育部重点实验室开放基金项目(szjj2019-011)

Effects of different propeller blades on gas-liquid two-phase mixing characteristics in stirred reactor

Yibin LI1,2(),Yajuan SONG1,Xiaohui DAI1,Zhenggui LI3   

  1. 1.School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu, China
    2.Gansu Key Laboratory of Fluid Machinery and Systems, Lanzhou 730050, Gansu, China
    3.Key Laboratory of Fluid and Power Machinery, Xihua University, Chengdu 610039, Sichuan, China
  • Received:2019-11-04 Revised:2020-01-07 Online:2020-04-25 Published:2020-04-25
  • Contact: Yibin LI

摘要:

为了研究不同推进式桨叶对搅拌反应器内气液两相混合特性的影响,以某搅拌反应器的推进式桨叶为研究对象,将搅拌聚合物简化为含5%气体的清水介质,基于螺旋桨叶片设计方法和CFD流场仿真技术,采用VOF多相流模型和RNG k-ε 湍流模型,对四种推进式桨叶内部气液两相流动进行数值分析,实现了推进式桨叶参数设计和性能优化。分析设计转速在400 r/min时的径向速度、0~18 s的时间范围内气体体积分数的变化、无量纲气体体积分数以及无量纲轴向速度,来评价四种推进式搅拌反应器搅拌性能的剪切、混合、分散。研究结果表明:变螺旋角(FDC-450-γ)非对称桨叶的流动更均匀、混合速率更快和剪切分散能力能强。通过对四种不同推进式桨叶的比较分析,为后续的研究和工程实践奠定了基础。

关键词: 推进式桨叶, 两相流, 混合特性, 计算流体力学, 搅拌器

Abstract:

A stirred reactor is a device that supplies mechanical energy to a stirred medium by obtaining a suitable flow field. It is widely used in industrial production, especially in the chemical industry, and many chemical production applications are more or less affected by the effect of stirring. Due to the lack of data on the design parameters of propeller blades at home and abroad, the profile of propeller blades is poor, and the stirring performance needs to be improved. In order to study and compare the stirring effect of several propeller blades, the propelling blade of the stirred reactor is taken as the research object, and polymerization medium of the mixing reactor is simplified to water and gas. First, the propeller blades are designed according to the design parameters. Four different types of propeller blades are designed by using different helix angles and contour shapes. Then, three-dimensional diagrams of the four propelled stirred reactors are drawn and unstructured meshing is performed according to the two-dimensional diagrams. Finally, the internal flow characteristics of the four propelled stirred reactors were simulated and analyzed by using multiple reference frames, VOF multiphase flow models, and RNG k-ε turbulence models. When the speed is 400 r/min, we qualitative analyze the distribution and uniformity of radial velocity and the mixing degree through comparing radial velocity cloud graph and the variation of gas volume fraction cloud graph from 0 to 18 s (including 0.6 s, 6 s, 12 s and 18 s). Besides we also define the dimensionless gas volume fraction and axial velocity, so 0 to 18 s (including 0.6 s, 6 s, 12 s and 18 s) hybrid rate,distribution of the gas volume fraction and the rate of change of the axial velocity are quantitative analyzed. According to the results of numerical simulation, the mixing characteristics and mixing degrees of the four types of propelled stirred reactors were compared. We can draw the following conclusions the asymmetric blades with variable spiral angle (FDC-450-γ) has a more uniform flow rate, the mixing rate is faster and the mixing degree is better. In this paper, four different propeller blades are selected for comparison and analysis, which lays the foundation for subsequent research and engineering practice.

Key words: propeller blade, two-phase flow, mixing characteristics, computational fluid dynamics, stirred vessel

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