Lattice Boltzmann simulation for phase separation with chemical reaction controlled by thermal diffusion

Area of Science:

• Physical Chemistry
• Fluid Dynamics
• Materials Science

Background:

• Phase separation in binary fluids is crucial for material properties.
• Understanding pattern formation under chemical reaction and thermal diffusion is complex.
• Lattice Boltzmann Method (LBM) is a powerful tool for simulating fluid dynamics.

Purpose of the Study:

• Investigate phase separation behavior and pattern formation in a binary fluid with chemical reaction.
• Evaluate the coupling effects of pre-exponential factor (K), viscosity, and thermal diffusion (D) on phase separation.
• Assess the influence of thermal diffusion versus concentration on morphology and dynamics during slow cooling.

Main Methods:

• Incorporation of the Arrhenius equation into the lattice Boltzmann method (LBM).
• Extended LBM used to simulate binary mixtures under chemically reacting conditions and slow cooling.
• Systematic evaluation of parameters: pre-exponential factor (K), viscosity, and thermal diffusion (D).

Main Results:

• Increased viscosity and thermal diffusion (D) yield interconnected structures (ISs) and lamellar structures (LSs) for small K.
• Concentric phase-separated structures (CSs) emerge with large K.
• Decreased viscosity and increased thermal diffusion significantly enhance phase separation degree and efficiency.

Conclusions:

• Viscosity, thermal diffusion, and the pre-exponential factor critically control phase separation morphology in reacting binary fluids.
• The study provides insights into designing materials with specific microstructures through controlled phase separation.
• Extended LBM offers a robust framework for simulating complex fluid phenomena.