Phase-field lattice Boltzmann model for two-phase flows with large density ratio.
Shengyuan Zhang1, Jun Tang1, Huiying Wu1
1School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Physical Review. E
|February 23, 2022
Summary
This study introduces a lattice Boltzmann (LB) model using the phase-field method for simulating two-phase flows with large density ratios. The novel model accurately captures complex fluid dynamics, validated against benchmarks.
Area of Science:
- Computational Fluid Dynamics
- Multiphase Flow Physics
- Phase-Field Modeling
Background:
- Simulating two-phase flows with significant density differences presents challenges for existing computational models.
- Accurate modeling is crucial for understanding phenomena in various engineering applications.
Purpose of the Study:
- To develop a robust lattice Boltzmann (LB) model capable of simulating large density ratio two-phase flows.
- To improve the accuracy and efficiency of phase-field-based LB methods.
Main Methods:
- Developed a multiple-relaxation-time (MRT) lattice Boltzmann equation to solve the conserved Allen-Cahn equation without deviation terms.
- Modified the equilibrium distribution function and discrete source term for accurate Allen-Cahn equation recovery.
- Simplified and modified the discrete force term in the LB equation for incompressible Navier-Stokes equations.
- Introduced an alternative scheme to compute gradient terms using the nonequilibrium part of the distribution function.
Main Results:
- The proposed MRT LB equation accurately solves the conserved Allen-Cahn equation, avoiding temporal derivative calculations.
- The model successfully simulates benchmark cases of large density ratio two-phase flows, including Poiseuille flow, droplet impact, and Taylor bubbles.
- Numerical results show excellent agreement with analytical, numerical, and experimental data.
Conclusions:
- The developed LB model provides a reliable and accurate method for simulating large density ratio two-phase flows.
- The improvements in the MRT LB equation and discrete force term enhance the simulation capabilities for complex interfacial phenomena.
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