Chemical-potential multiphase lattice Boltzmann method with superlarge density ratios.

Area of Science:

• Multiphase flow modeling
• Computational fluid dynamics
• Statistical physics

Background:

• The liquid-gas density ratio is crucial for multiphase flow simulations.
• Existing methods struggle with extremely large density ratios.
• Accurate modeling is essential for understanding real fluid systems.

Purpose of the Study:

• To develop a chemical-potential multiphase lattice Boltzmann method capable of handling extremely large liquid-gas density ratios.
• To ensure thermodynamic consistency and computational accuracy in simulations.
• To validate the model's performance in dynamic flow scenarios.

Main Methods:

• Construction of a chemical-potential multiphase lattice Boltzmann method.
• Decoupling mesh and momentum spaces using a proportional coefficient.
• Application of a compact finite-difference method for high-order accuracy.
• Inclusion of an upper limit for chemical potential to enhance stability.

Main Results:

• Achieved liquid-gas density ratios exceeding 10^14 at very low temperatures.
• Maintained thermodynamic consistency across extreme density ratios.
• Suppressed spurious currents to very low levels even with density ratios up to tens of thousands.
• Verified Galilean invariance of the model through drop splashing simulations.

Conclusions:

• The developed method accurately models multiphase flow with extremely large density ratios.
• The approach preserves thermodynamic consistency and computational accuracy.
• The model is robust and suitable for simulating complex fluid dynamics phenomena.