TWO-PHASE FLUID SUBJECTED TO TERRESTRIAL OR SPACE CONDITIONS: A LATTICE BOLTZMANN STUDY

A lattice Boltzmann model for two-phase fluids is used to find the equilibrium distribution of density and pressure across a vertical column under the action of terrestrial gravitational field. At low temperatures and without surface tension, the density distribution has a discontinuity point due to phase separation, while the pressure is always continuous. At temperatures far above the critical point, the fluid column behaves as an ideal gas and the well-known barometric formula is recovered. When surface tension is considered, this model gives also the correct behavior of a Van der Waals fluid placed in a tank subjected to terrestrial or space conditions in both cases, when the tank walls are wetted or not by the fluid.