Consistent evaporation formulation for the phase-field lattice Boltzmann method

Area of Science:

• Computational fluid dynamics
• Phase-field modeling
• Evaporation phenomena

Background:

• Accurate modeling of evaporation is crucial for various applications.
• Existing methods may lack consistency or require complex source terms.
• Phase-field lattice Boltzmann methods offer a promising approach for complex interface phenomena.

Purpose of the Study:

• To develop a consistent evaporation model for the Allen-Cahn-based phase-field lattice Boltzmann method.
• To incorporate an appropriate source term for recovering the advection-diffusion equation of specific humidity.
• To validate the proposed scheme against established analytical and numerical models.

Main Methods:

• Development of a conservative Allen-Cahn-based phase-field lattice Boltzmann method.
• Implementation of a source term to model specific humidity advection-diffusion.
• Numerical simulations of 1D Stefan flow with a flat interface.
• Numerical simulations of 3D evaporating sessile droplets on a flat substrate with a curved interface.

Main Results:

• The model accurately reproduces the evaporative mass flux for Stefan flow within a specific humidity range (≤0.8).
• Simulations of sessile droplets show good agreement with the Hu and Larson model regarding contact angle dependence on evaporative mass flux.
• The scheme effectively captures evaporation dynamics for both flat and curved interfaces.

Conclusions:

• The developed evaporation model is consistent and accurate for phase-field lattice Boltzmann simulations.
• The method provides reliable predictions for evaporation under various interface conditions.
• This work advances the capability of lattice Boltzmann methods in simulating complex evaporation processes.