Numerical Simulations of 1-D Two-Phase Flow with Non-Zero Mass Fluxes: Application to Phase Separation at 9° N (EPR) and the Main Endeavour Vent Field (JDF)

Numerical simulations of vertical one-dimensional two-phase flow with non-zero mass fluxes can help to enumerate and describe the different parameter space regimes at which phase separation can occur in submarine hydrothermal systems. Our simulations suggest that there are at least two such quasi-steady state regimes, corresponding to low and high mass fluxes imposed at the bottom of the system. For relatively low mass fluxes (10^-5 - 10^-4 kg/m²-s), a low salinity vapor-rich region forms near the top of the system, and high-salinity brine flows downward, raising the salinity in the lower half of the system. For high mass fluxes (&\sim 10^{-3} kg/m^{2}-s), both vapor and brine flow upward, with the vapor moving more quickly than the brine. In this case, phase separation results in higher salinities near the top of the system, corresponding to a mixture of brine and vapor, and salinities approaching that of normal seawater lower in the system. Bulk surface salinities in the high-flux regime are qualitatively consistent with vent fluid salinities at hydrothermal systems such as 9\deg$N on the East Pacific Rise and some of the vents of the Main Endeavour Field on the Juan de Fuca Ridge. Our future work will further test this preliminary analysis.