Asymmetric Bubble Formation at Rectangular Orifices

Area of Science:

• Fluid dynamics
• Multiphase flow phenomena
• Heat and mass transfer

Background:

• Bubble formation is vital in nature and industry, particularly in boiling for thermal management.
• Asymmetric bubble formation at slits and in convective flows is poorly understood compared to symmetric cases.
• Previous research primarily focused on symmetric bubble formation at circular orifices.

Purpose of the Study:

• To experimentally investigate bubble formation dynamics at rectangular orifices.
• To analyze the effects of orifice size, aspect ratio, and gas flow rate on bubble size.
• To develop predictive models for bubble size in both quasi-static and dynamic regimes.

Main Methods:

• Experimental investigation of bubble formation at rectangular orifices.
• Analysis of asymmetric bubble shape evolution and bubble neck size.
• Development of static force balance and dynamic models incorporating Bond and Weber numbers.

Main Results:

• Bubble neck size is governed by orifice dimensions or capillary length.
• A static force balance model predicts quasi-static bubble size, identifying Bond number and aspect ratio roles.
• A dynamic model using Weber number explains bubble size evolution under gas flow influence.

Conclusions:

• Provides a physical understanding of asymmetric bubble formation dynamics at rectangular orifices.
• Offers guidance for predicting bubble size in systems with asymmetric orifices.
• Enhances knowledge applicable to thermal management and industrial processes involving bubble generation.