Numerical Simulation of Single Argon Bubble Rising in Molten Metal Under a Laminar Flow

Abstract

The fundamental aspects of rising argon bubbles in molten metal for a laminar flow were investigated by numerical simulations. The Volume‐of‐Fluid (VOF) model was used to track the interface between argon and liquid metal. The process of a bubble rising in the molten metal includes two steps, one is the bubble rising inside the liquid, and the other one is the bubble rising across the liquid surface. The bubbling dynamics inside the liquid phase was studied in terms of the bubble's trajectory, shape and terminal velocity over a wide range of bubble diameters. It shows that ≈3–10mm bubbles rise in a spiral way with strong instabilities by changing their instantaneous shapes, while ≈10–20mm bubbles rise rectilinearly and their shapes are kept almost steady. All these bubbles' terminal velocities are around 0.3 m s−1, which are in accordance with literature data. For a bubble with a specific size, small metal droplets can be formed due to the bubble bursting on the free surface. In a situation when the top surface of the bubble is ruptured, the remains of the bubble will collapse and jet droplets can be formed. Simulations of jet droplets were qualitatively analyzed. It shows that when the surface tension is 1.4 N m−1, the critical bubble size is 9.3 mm. Also, the ejection is found to increase with an increased surface tension value, unless a critical bubble size is reached.

Motion of Single Bubble and Interactions between Two Bubbles in Liquid Steel

“…Zhang et al 31) calculated the terminal velocities of gas bubbles in liquid steel from different models and obtained a smoothed mean value. Xu et al 32) also obtained the bubble terminal velocity by the VOF mode. The present simulation results show that the bubble terminal velocities are around 0.32 m/s for the current conditions.…”

Numerical investigation of single bubble dynamics in liquid sodium pool

“…Numerical simulations are carried out to understand the effect of initial bubble diameter on bubble dynamics for argon gas and liquid sodium system at 473 K. The domain height 'H' and width 'W' are taken as ''8 d B '' so that the bubble reaches terminal velocity and side wall effects can be ignored [12]. The different bubble diameters considered for the analysis are 10 mm, 15 mm and 20 mm.…”

“…This represents a complement to experimental measurements and provides better physical understanding of the phenomenon. Several numerical studies have been carried out to date to understand single bubble rise dynamics in stagnant liquids [8][9][10][11][12][13][14][15]. In source term evaluation studies related to SFR, single bubble dynamics in sodium pool is typically studied for a bubble size range from 10 mm to 30 mm [2,16,17] based on the maximum stable bubble size evaluated from fluid properties.…”

A Numerical Study about the Influence of a Bubble Wake Flow on the Removal of Inclusions

“…3(d) shows that the bubble rises in a zigzag way, which is in accordance with the results from a previous study. 10) The area of the bubble wake flow which can make the inclusions rise is defined as the inclusion rising zone. 16) To study the width of the rising zone, the particles' velocity field of Fig.…”

“…2,8,9) Meanwhile, the injected bubbles are also experiencing complicated phenomena such as a coalescence and breakup as well as a shape change. 3,10) It is hard to consider all the details in a quantitative model, especial for a large industrial scale reactor. In other words, more assumptions and empirical formula are needed to enable implementations to simulate a large scale reactor.…”