This study aims to provide discussions of the numerical method and the bubbly flow characteristics of an annular bubble plume.
The bubbles, released from the annulus located at the bottom of the domain, rise owing to buoyant force. These released bubbles have diameters of 0.15–0.25 mm and satisfy the bubble flow rate of 4.1 mm3/s. The evolution of the three-dimensional annular bubble plume is numerically simulated using the semi-Lagrangian–Lagrangian (semi-L–L) approach. The approach is composed of a vortex-in-cell method for the liquid phase and a Lagrangian description of the gas phase.
First, a new phenomenon of fluid dynamics was discovered. The bubbly flow enters a transition state with the meandering motion of the bubble plume after the early stable stage. A vortex structure in the form of vortex rings is formed because of the inhomogeneous bubble distribution and the fluid-surface effects. The vortex structure of the flow deforms as three-dimensionality appears in the flow before the flow fully develops. Second, the superior abilities of the semi-L–L approach to analyze the vortex structure of the flow and supply physical details of bubble dynamics were demonstrated in this investigation.
The semi-L–L approach is applied to the simulation of the gas–liquid two-phase flows.
This study was supported by a grant from the Project of Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development of the Ministry of Education, Culture, Sports, Science and Technology, Japan.
Nguyen, V., Degawa, T. and Uchiyama, T. (2019), "Numerical simulation of annular bubble plume by vortex in cell method", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 29 No. 3, pp. 1103-1131. https://doi.org/10.1108/HFF-03-2018-0094Download as .RIS
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