Phase segregation of liquid-vapor systems with a gravitational field

Abstract

Phase separation in the presence of external forces has attracted considerable attention since the initial works for solid mixtures. Despite this, only very few studies are available which address the segregation process of liquid-vapor systems under gravity. We present here an extensive study which takes into account both hydrodynamic and gravitational effects on the coarsening dynamics. An isothermal formulation of a lattice Boltzmann model for a liquid-vapor system with the van der Waals equation of state is adopted. In the absence of gravity, the growth of domains follows a power law with the exponent $2/3$ of the inertial regime. The external force deeply affects the observed morphology accelerating the coarsening of domains and favoring the liquid accumulation at the bottom of the system. Along the force direction, the growth exponent is found to increase with the gravity strength still preserving sharp interfaces since the Porod's law is found to be verified. The time evolution of the average thickness $L$ of the layers of accumulated material at confining walls shows a transition from an initial regime where $L\simeq t^{2/3}$ ($t$: time) to a late-time regime $L\simeq g{t}^{5/3}$ with $g$ the gravitational acceleration. The final steady state, made of two overlapped layers of liquid and vapor, shows a density profile in agreement with theoretical predictions.

References in corpus (17)

• Theory of Phase Ordering Kinetics
• Inertial effects in three dimensional spinodal decomposition of a symmetric binary fluid mixture: A lattice Boltzmann study
• Eliminating spurious velocities in the free energy lattice Boltzmann method
• Finite difference lattice Boltzmann model with flux limiters for liquid-vapor systems
• Phase separation in thermal systems: LB study and morphological characterization
• Interface Width and Bulk Stability: requirements for the simulation of Deeply Quenched Liquid-Gas Systems
• Universality in Fluid Domain Coarsening: The case of vapor-liquid transition
• Stripe formation in differentially forced binary systems
• Nucleation and Growth of Droplets in Vapor-Liquid Transitions
• Entropy production in thermal phase separation: a kinetic-theory approach
• Cavitation inception of a van der Waals fluid at a sack-wall obstacle
• Corner transport upwind lattice Boltzmann model for bubble cavitation
• A lattice Boltzmann study of phase separation in liquid-vapor systems with gravity
• Pattern Formation in Liquid-Vapor Systems under Periodic Potential and Shear
• Droplet growth during vapor-liquid transition in a 2D Lennard-Jones fluid
• Growth regimes in three-dimensional phase separation of liquid-vapor systems
• Simulating liquid-vapor phase separation under shear with lattice Boltzmann method