Growth regimes in three-dimensional phase separation of liquid-vapor systems

The liquid-vapor phase separation is investigated via lattice Boltzmann simulations in three dimensions. After expressing length and time scales in reduced physical units, we combined data from several large simulations (on 5123 nodes) with different values of viscosity, surface tension, and temperature, to obtain a single curve of rescaled length l as a function of rescaled time t. We find evidence of the existence of kinetic and inertial regimes with growth exponents alpha d = 1/2 and alpha i = 2/3 over several time decades, with a crossover from alpha d to alpha i at t <^> 1. This allows us to rule out the existence of a viscous regime with alpha,, = 1 in three-dimensional liquid-vapor isothermal phase separation, differently from what happens in binary fluid mixtures. An in-depth analysis of the kinetics of the phase separation process, as well as a characterization of the morphology and the flow properties, are further presented in order to provide clues into the dynamics of the phase-separation process.