Complex bubble deformation and break-up dynamics studies using interface capturing approach
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Vol. 2, No. 4, 2020, 00–00 https://doi.org/10.1007/s42757-020-0073-3
Complex bubble deformation and break-up dynamics studies using interface capturing approach Yuqiao Fan1, Jun Fang2, Igor Bolotnov1 () 1. Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695, USA 2. Nuclear Science and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA
Abstract
Keywords
The dynamics of bubble deformation has significant impacts on two-phase flow fundamentals
two-phase flow DNS
such as bubble induced turbulence and flow regime transition. Despite the significant progress achieved by experimental studies on bubble deformation, certain limitations still exist especially for wide-range datasets. To significantly expand the flow conditions available from experiments,
level-set method
direct numerical simulation (DNS) is utilized to study the bubble–liquid interactions using finiteelement solver with level-set interface capturing method. Different from conventional investigations
PID bubble controller
of bubble rising and deforming in stagnant liquids, a proportional-integral-derivative (PID) bubble
Article History
controller is leveraged to maintain the bubble location in uniform liquid flow. This paper evaluates the reliability and reproducibility of the PID bubble controller for complex bubble deformation
Received: 29 February 2020
studies through a comprehensive set of verification and validation studies. An improved bubble
Accepted: 25 April 2020
deformation map is developed, based on Weber number and bubble Reynolds number, showing six zones for different deformation and break-up mechanisms. This research aims at producing virtual experiment level data source using interface resolved DNS and shedding light into the
Research Article
bubble deformation bubble break-up
Revised: 22 April 2020
© Tsinghua University Press 2020
physics of interface dynamics. The insights obtained can be further incorporated in improved multiphase CFD models to guide the engineering designs and industrial processes where bubble deformation and break-up play a pivotal role.
1
Introduction
Bubble deformation is a ubiquitous phenomenon in gas– liquid two-phase flow and has significant impacts on various interface related flow physics. For example, bubble induced turbulence has distinct characteristics from particle induced turbulence. The existence of bubbles can either augment or suppress local liquid turbulence given specific bubble deformability (Gore and Crowe, 1989); in other words, the turbulent intensity change depends on the bubble distortion level (Feng and Bolotnov, 2017a). In addition, the bubble deformation also plays an important role in determining bubble interfacial forces, such as drag force, lift force, and virtual mass force (Bhaga and Weber, 1981). Severe deformation may result in bubble break-up, which leads to more complex flow regimes. One such example is the slug bubble during the slug-to-churn flow regime transition (Zimmer and Bolotnov, 2019). As the gas f
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