Modeling Bubble Collisions at Liquid?Liquid and Compound Interfaces.

Area of Science:

• Fluid Dynamics
• Interfacial Science
• Multiphase Flow

Background:

• Bubble collisions at interfaces are crucial in various industrial processes.
• Previous models primarily relied on grid-based simulations, limiting their scope.
• Understanding bubble dynamics at compound interfaces (liquid-liquid, solid-liquid-liquid, gas-liquid-liquid) is essential.

Purpose of the Study:

• To model bubble collision dynamics at liquid-liquid, solid-liquid-liquid, and gas-liquid-liquid interfaces.
• To predict bubble velocity profiles, film pressure buildup, and drainage rates.
• To introduce a novel force balance approach for these complex interface types.

Main Methods:

• A force balance approach considering buoyancy, drag, added mass, and film forces.
• Application of the augmented Young-Laplace equation for pressure buildup.
• Utilizing lubrication theory and the Stokes-Reynolds equation for film drainage.
• Experimental validation using water and silicone oils with varying viscosities.

Main Results:

• The model accurately predicts bubble velocity profiles at various impact velocities and film thicknesses.
• Reasonable agreement between theoretical predictions and experimental data was observed.
• The study presents spatiotemporal evolution of film thickness and pressure, not previously captured experimentally.

Conclusions:

• The developed force balance model provides a robust framework for analyzing bubble collisions at compound interfaces.
• This approach overcomes limitations of previous grid-based simulations.
• The findings enhance understanding of interfacial phenomena in multiphase systems.