The thermocapillary migrations of two bubbles in microgravity environment

Area of Science:

• Fluid dynamics
• Microgravity science
• Interfacial phenomena

Background:

• Thermocapillary effects drive fluid motion due to surface tension gradients caused by temperature differences.
• Understanding bubble dynamics is crucial for multiphase flow applications in microgravity.
• Interactions between multiple bubbles can significantly alter individual and collective motion.

Purpose of the Study:

• To theoretically investigate the thermocapillary migration of two interacting bubbles in a uniform temperature gradient.
• To derive accurate migration velocities for bubbles in a microgravity environment.
• To analyze the influence of bubble proximity, size, and thermal gradients on bubble interactions.

Main Methods:

• The study employs theoretical analysis, solving momentum and energy equations.
• The method of reflections is utilized to handle bubble interactions.
• Coordinate transformations are used for analytical progression.

Main Results:

• Accurate migration velocities for two bubbles were derived for small Marangoni and Reynolds numbers.
• The proximity of the second bubble to the first intensifies their mutual interaction.
• Bubble size and thermal gradient effects on bubble interaction were estimated.

Conclusions:

• The approach of bubbles significantly enhances their thermocapillary interaction.
• This interaction leads to complex and interesting thermocapillary motions.
• The findings provide insights into multiphase flow behavior in microgravity conditions.