SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 45 ›› Issue (5): 268-283.DOI: 10.1016/j.cjche.2021.04.002

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Numerical study on hydrodynamic characteristics of spherical bubble contaminated by surfactants under higher Reynolds numbers

Tao Sun, Mingjun Pang, Yang Fei   

  1. School of Mechanical Engineering and Rail Transit, Changzhou University, Changzhou 213164, China
  • 收稿日期:2021-01-28 修回日期:2021-04-08 出版日期:2022-05-28 发布日期:2022-06-22
  • 通讯作者: Mingjun Pang,E-mail:pangmj@cczu.edu.cn
  • 基金资助:
    We gratefully acknowledge the financial support from the National Natural Science Foundation of China Fund (51376026) and Qinglan Project of Jiangsu province. We also wish to thank the reviewers and editors for helpful suggestions.

Numerical study on hydrodynamic characteristics of spherical bubble contaminated by surfactants under higher Reynolds numbers

Tao Sun, Mingjun Pang, Yang Fei   

  1. School of Mechanical Engineering and Rail Transit, Changzhou University, Changzhou 213164, China
  • Received:2021-01-28 Revised:2021-04-08 Online:2022-05-28 Published:2022-06-22
  • Contact: Mingjun Pang,E-mail:pangmj@cczu.edu.cn
  • Supported by:
    We gratefully acknowledge the financial support from the National Natural Science Foundation of China Fund (51376026) and Qinglan Project of Jiangsu province. We also wish to thank the reviewers and editors for helpful suggestions.

摘要: It is of significance to investigate deeply the hydrodynamic features of the bubble contaminated by impurities in view of the fact that the industrial liquid is difficult to keep absolutely pure. On the basis of the finite volume method, the bubble interface contaminated by the surfactant (1-pentanol) is achieved through solving the concentration transport equations in liquid and along the bubble interface, and solving the absorption and desorption equation at the bubble interface. And the three-dimensional momentum equation is solved at the same time. It is investigated in detail on the influence of interfacial contamination degrees (described with the cap angle θ) on hydrodynamic characteristics of the spherical bubble when the bubble Reynolds number (Re) is larger than 200. The θ is realized by changing the surfactant concentration (C0) in liquid. The present results show that the hydrodynamic characteristics, such as interfacial concentration, interfacial shear stress, interfacial velocity and wake flow, are related to both Re and C0 for the contaminated bubble. When C0 is relatively low in liquid (i.e., the contamination degree of the bubble interface is relatively slight), the hydrodynamic characteristics of the bubble can still keep the 2D features even if Re > 200. The decrease of θ or the increase of Re can promote the appearance of the unsteady wake flow. For the present investigation, when Re > 200 and θ ≤ 60°, the hydrodynamic characteristics of the bubble show the 3D phenomena, which indicates that axisymmetric model is no longer valid.

关键词: Bubble, Higher Reynolds number, Interfacial parameters, Wake flow, Adsorption, Desorption

Abstract: It is of significance to investigate deeply the hydrodynamic features of the bubble contaminated by impurities in view of the fact that the industrial liquid is difficult to keep absolutely pure. On the basis of the finite volume method, the bubble interface contaminated by the surfactant (1-pentanol) is achieved through solving the concentration transport equations in liquid and along the bubble interface, and solving the absorption and desorption equation at the bubble interface. And the three-dimensional momentum equation is solved at the same time. It is investigated in detail on the influence of interfacial contamination degrees (described with the cap angle θ) on hydrodynamic characteristics of the spherical bubble when the bubble Reynolds number (Re) is larger than 200. The θ is realized by changing the surfactant concentration (C0) in liquid. The present results show that the hydrodynamic characteristics, such as interfacial concentration, interfacial shear stress, interfacial velocity and wake flow, are related to both Re and C0 for the contaminated bubble. When C0 is relatively low in liquid (i.e., the contamination degree of the bubble interface is relatively slight), the hydrodynamic characteristics of the bubble can still keep the 2D features even if Re > 200. The decrease of θ or the increase of Re can promote the appearance of the unsteady wake flow. For the present investigation, when Re > 200 and θ ≤ 60°, the hydrodynamic characteristics of the bubble show the 3D phenomena, which indicates that axisymmetric model is no longer valid.

Key words: Bubble, Higher Reynolds number, Interfacial parameters, Wake flow, Adsorption, Desorption