Numerical simulations of bubble formation in liquid metal

https://doi.org/10.1016/j.ijmultiphaseflow.2020.103363Get rights and content
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Highlights

  • The bubbles in a steel-argon system are larger compared to the bubbles detached in a water-air system due to higher surface tension and higher wettability.

  • The differences in bubble volume become less significant at higher gas flow rates since the transition to the dynamic regime happens earlier in the water-air system.

  • The bubble at the orifice mouth becomes asymmetric due to the influences of shear flow and surface inclination angle.

  • The influence of fluid properties on the detached bubble volume decreases with increasing shear rate.

Abstract

The process of bubble formation from submerged orifices is encountered in various industrial applications. It is therefore essential to understand the dynamics of bubble formation under such conditions. In the present work, the process of bubble formation in a steel-argon system is studied using the Local Front Reconstruction Method (LFRM), a Front Tracking method that enables the simulation of interface merging and breakup. The numerical simulations are performed over a wide range of gas injection rates to study the bubble formation dynamics under quasi-static and dynamic regimes. The simulation results show that the detached bubbles in a steel-argon system are generally bigger compared to the bubbles detached in a water-air system due to higher surface tension and lower wettability. In liquid cross-flow, the bubble at the orifice mouth becomes asymmetric due to the drag force created by the liquid flow. Under non-wetting conditions, the bubble can slide over the orifice without forming a bubble neck when the orifice plate is sufficiently large. On the other hand, under wetting conditions, the detached bubble volume decreases when the orifice plate is gradually tilted from a horizontal to vertical orientation at lower shear rates. However, this trend reverses at higher shear rates because the drag force exerted by the flowing liquid becomes dominant.

Keywords

Numerical simulation
Local front reconstruction method
Bubble formation
Orifice
Liquid metal
Wetting

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