3.1. Framework
In the present research, two imperative multiphase models of
Eulerian-Eulerian and volume of fluid (VOF) are utilized. The VOF method
is a proper numerical technique to simulate the two-phase flows. The
gas-liquid interface is a critical feature of this modeling. The model
can be utilized to make the interface between the phases (a free surface
reconstruction technique). This technique is also employed for mass and
heat transfer in two-phase flows. In the present work, it was tried to
assess the weeping rate of a column armed with Nye trays for the whole
system not mainly for the gas-liquid interfaces. Consequently, an
Eulerian-Eulerian method was chosen for this work. Here, two sets of
transient CFD models in the 3D framework were established to investigate
the single and two-phase flows via a full three-dimensional geometry of
the circular distillation column. The Eulerian-Eulerian multiphase flow
was utilized where the phases are treated as interpenetrating continua.
Furthermore, the pressure velocity coupling was incorporated using the
SIMPLE algorithm. To solve the transient equations prior to reaching the
quasi mode, the time period of 0.002 s was considered. The upwind
technique was also used for the advection discretization scheme and
second-order backward Euler for integrating the time. The equations of
momentum balance, species conservation, and mass conservation were
solved but the energy conservation was neglected due to the isothermal
system.