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The detachment regimes and corresponding detachment height of lower liquid from a coated bubble during the bubble passage through an immiscible liquid–liquid interface were studied. High-speed imaging techniques were used to visualize the lower liquid detachment from a rising bubble near the interface. Analysis of industrial slag samples by a scanning electron microscope (SEM) was also carried out. The results indicate that the detachment height of lower liquid from a rising bubble showed a distinct correlation to penetration regimes. Bubble size and a fluid's physical properties exerted a significant influence on the detachment height of the lower liquid. The detachment height for medium bubbles (Weber number: 4~4.5; Bond number: 2.5~7.5) varied significantly with increasing bubble size, which contributes to the lower liquid entrainment in the upper phase due, significantly, to the higher detachment height and large entrainment volume. The maximum detachment height for large bubbles is limited to approximately 100 mm due to the early detachment with the liquid column at the interface though large bubbles transporting a larger volume of lower liquid into the upper phase. [ABSTRACT FROM AUTHOR]

The detachment regimes and corresponding detachment height of lower liquid from a coated bubble during the bubble passage through an immiscible liquid–liquid interface were studied. High-speed imaging techniques were used to visualize the lower liquid detachment from a rising bubble near the interface. Analysis of industrial slag samples by a scanning electron microscope (SEM) was also carried out. The results indicate that the detachment height of lower liquid from a rising bubble showed a distinct correlation to penetration regimes. Bubble size and a fluid’s physical properties exerted a significant influence on the detachment height of the lower liquid. The detachment height for medium bubbles (Weber number: 4~4.5; Bond number: 2.5~7.5) varied significantly with increasing bubble size, which contributes to the lower liquid entrainment in the upper phase due, significantly, to the higher detachment height and large entrainment volume. The maximum detachment height for large bubbles is limited to approximately 100 mm due to the early detachment with the liquid column at the interface though large bubbles transporting a larger volume of lower liquid into the upper phase.

To control the behavior of underwater bubbles, stainless steel meshes are treated through femtosecond laser processing, and the bubble absorption, bubble interception, and unidirectional bubble passage are realized by using structured meshes. The surface of the mesh presents a micro–sub‐micro–nano trinary‐scale structure (microscale mesh wires, sub‐microripples, and nanoparticles) after one‐step laser ablation on both sides. The surface shows superhydrophilic in air and superaerophobic once immersed in water. After further modified with fluoroalkylsilane, the wettability of the sample surface is switched to be superaerophilic in water with bubble being absorbed by the sample. When a plenty of underwater bubbles arrive at the structured stainless steel mesh surface, they can be blocked by the underwater superaerophobic mesh but pass through the underwater superaerophilic mesh. In addition, after the mesh being treated only one side and further modified, it is to be Janus mesh and presents asymmetrical wettability of aerophilicity/superaerophilicity. The Janus mesh shows the unidirectional passage of underwater bubbles. Bubbles can only penetrate from aerophilic side to superaerophilic side, but be blocked from the other direction. The mesh is verified to be used to eliminate the stuck bubbles in the container. [ABSTRACT FROM AUTHOR]

Herein, the volume of fluid (VOF) model is applied to simulate the phenomenon caused by the bubble motion from the molten metal into a slag. First, the mathematical model is validated by the experimental data from the literature. Then, the model is used to quantitatively predict the process of a single argon bubble passage from the liquid steel into the liquid slag. Finally, a parametric study is conducted to determine how the bubble diameter and the interfacial tension influence the bubble movement. The simulation results show that the bubble passing patterns at the steel–slag interface are oscillation‐pass, oscillations‐breakup, oscillations‐pass, pass, and pass‐breakup for the 3, 5, 7, 10, and 15 (20) mm bubbles, respectively. For a 5 mm bubble, it is found that an increase in the interfacial tension from 0.04 to 0.8 N m−1 results in a delayed bubble passage time. The results also show that the bubble experiences an oscillations‐breakup process if the interfacial tension value is up to 1.15 N m−1. However, a higher interfacial tension value (1.8 N m−1) can make the bubble pass again but with a longer passage time. [ABSTRACT FROM AUTHOR]

Bubble Passage: Underwater Superaerophobicity/Superaerophilicity and Unidirectional Bubble Passage Based on the Femtosecond Laser-Structured Stainless Steel Mesh (Adv. Keywords: bubble passage; femtosecond laser; Janus mesh; underwater superaerophilicity; underwater superaerophobicity EN bubble passage femtosecond laser Janus mesh underwater superaerophilicity underwater superaerophobicity 1 1 1 07/29/20 20200723 NES 200723 The bubbles' behavior could be controlled by the structured stainless steel mesh fabricated by the combination of one-step femtosecond laser ablation and chemical modification. Bubble passage, femtosecond laser, Janus mesh, underwater superaerophilicity, underwater superaerophobicity. [Extracted from the article]