Fig. 10 Distribution of water at an acceleration of 0.002
nm/ps2 and Cw = 71.43% in 5nm, 10nm, 15nm H-H pores.
The hydrocarbon molecules are not shown. The result indicates that at
each pore size, the peaks and troughs in the velocity profiles
correspond to the local density of each of the phases.
4.2 Fluid Transport in P-H
Nanopores
In the previous section, we reviewed transport of water and hydrocarbon
in H-H pore systems where water bridges are largely absent except under
some specific conditions. In this section, we present the corresponding
results for P-H pores where water bridges are prevalent across multiple
pore sizes and water concentrations.
The water and hydrocarbon velocity profiles for 54 NEMD simulations in
P-H nanopore are provided in Figs. S6-7 in Supporting Information. In
this section, we only analyze a few representative hydrocarbon-water
velocity profiles in P-H nanopores and address the effects of pore size,
water concentration and electric
field (the effects of acceleration
are provided in Supporting Information).
Effect of Pore size
Fig.11 shows the water (Fig.11a) and hydrocarbon (Fig.11b) velocity
profiles at an acceleration and water concentration of 0.002
nm/ps2 and 71.43% respectively in different P-H
nanopore sizes. Water and hydrocarbon velocities increase with an
increase of pore size which is in agreement with Liu et
al.41. Additionally, water and hydrocarbon velocity
profiles are parabolic in the 5 nm P-H nanopore and show flatter
profiles for the 10nm and 15nm pores with increasing distance from the
pore walls and the accompanying decrease in fluid-pore wall
interactions.