Lattice-Boltzmann algorithm for simulating thermal two-phase flow

Area of Science:

• Computational fluid dynamics
• Thermodynamics
• Multiphase flow

Background:

• Lattice-Boltzmann methods are widely used for fluid flow simulations.
• Incorporating thermal effects into two-phase flow simulations presents significant challenges.
• Existing models for thermal flow and two-phase flow have limitations.

Purpose of the Study:

• To develop and validate a novel algorithm for lattice-Boltzmann simulations of two-phase flow with thermal effects.
• To address discrepancies in previous thermal flow models for nonideal systems.
• To provide a more accurate simulation tool for phenomena like evaporation and condensation.

Main Methods:

• Combining a two-distribution model for single-phase thermal flow with a thermodynamically-based model for isothermal two-phase flow.
• Correcting the thermal energy flux description from internal energy gradient to temperature gradient.
• Implementing and testing the algorithm on various benchmark problems.

Main Results:

• The algorithm successfully incorporates thermal effects into lattice-Boltzmann simulations of two-phase flow.
• Simulations accurately reproduced phenomena such as free-standing liquid film formation, film evaporation, droplet evaporation, and channel condensation.
• The corrected thermal energy flux model showed improved accuracy for nonideal systems compared to classical hydrodynamics.

Conclusions:

• The developed algorithm provides a robust and accurate method for simulating thermal two-phase flow.
• This advancement is crucial for understanding and predicting complex fluid dynamics phenomena involving heat transfer.
• The corrected model offers a systematic improvement over previous approaches for nonideal fluid systems.