Modelo de campo medio para la distribución de tamaños de burbujas en espumas húmedas en maduración

Área de la Ciencia:

• Physics
• Colloid and Surface Science
• Materials Science

Sus antecedentes:

• Aqueous foams undergo coarsening, a process where gas diffuses from smaller to larger bubbles, altering bubble size distribution over time.
• While foams are expected to reach a statistically invariant scaling state, a predictive model for this state, especially concerning liquid fraction, is lacking.

Objetivo del estudio:

• To develop a predictive model for the bubble-size distribution in the scaling state of aqueous foams with varying liquid content.
• To validate this model against simulations and experimental data, and to understand the influence of liquid fraction on foam coarsening.

Principales métodos:

• Proposed a three-dimensional mean-field bubble growth law for foams without inter-bubble adhesion.
• Validated the growth law against bubble-scale simulations.
• Used mean-field simulations to derive and verify the scaling-state bubble-size distribution for different liquid fractions (ϕ).

Principales resultados:

• Derived a prediction for the scaling-state bubble-size distribution as a function of liquid fraction (ϕ) up to the unjamming transition (ϕc ≈ 36%).
• Verified that the derived scaling state is approached from various initial conditions.
• Observed a large population of small bubbles for ϕ > 0, consistent with some prior studies but with notable differences attributed to the model's exclusion of rattler bubbles.

Conclusiones:

• The developed mean-field model provides a theoretical framework for predicting the bubble-size distribution in the scaling state of aqueous foams.
• The model highlights the importance of liquid fraction in determining foam coarsening dynamics and the final bubble-size distribution.
• The study identifies the absence of rattler bubbles in the model as a key factor for observed differences compared to previous experimental and simulation results.