Engulfment of a drop on solids coated by thin and thick fluid films

Abstract

When an aqueous drop contacts an immiscible oil film, it displays complex interfacial dynamics. When the spreading factor is positive, upon contact, the oil spreads onto the drop's liquid–air interface, first forming a liquid bridge whose curvature drives an apparent drop spreading motion and later engulfs the drop. We study this flow using both three-phase lattice Boltzmann simulations based on the conservative phase field model, and experiments. Inertially and viscously limited dynamics are explored using the Ohnesorge number $Oh$ and the ratio between the film height $H$ and the initial drop radius $R$ . Both regimes show that the radial growth of the liquid bridge $r$ is fairly insensitive to the film height $H$ , and scales with time $T$ as $r\sim T^{1/2}$ for $Oh\ll 1$ , and as $r\sim T^{2/5}$ for $Oh\gg 1$ . For $Oh\gg 1$ , we show experimentally that this immiscible liquid bridge growth is analogous with the miscible drop–film coalescence case. Contrary to the growth of the liquid bridge, however, we find that the late-time engulfment dynamics and final interface profiles are significantly affected by the ratio $H/R$ .

Experiments on Steam Injection into Preformed Steam Chambers of Various Shapes for Maximum Condensate Recovery

“…Recent studies have shown that when an aqueous drop contacts an immiscible oil film, it displays complex interfacial dynamics. When the spreading factor is positive, upon contact, the oil spreads onto the drop's liquid interface, first forming a liquid bridge whose curvature drives an apparent drop-spreading motion and then engulfing the drop [33]. We also believe that the local curvature of each steam chamber used in experiments may influence the downward flow intensity through the effective gravity.…”

“…It should be mentioned that, by following the evolution of the condensation front, we can confirm that the condensation must occur at the steam chamber edge (Figures 4 and 8); however, in our experiments, the condensate water wets the cast iron edge [32] of the preformed steam chamber. Such conditions produce a substrate coated with a water film that absorbs the water drops contacting the film [33]. On the contrary, in actual SAGD processes, the condensate water does not wet the steam chamber edge, which essentially is in the base oil phase, i.e., both fluids are immiscible; nevertheless, the produced fluids in the SAGD recovery method have been reported to be in emulsion form (the most common range of emulsified water in light crudes (>20 API) is 5-20 vol% and it is 10-35 vol% in heavier crudes (<20 API) [34,35], which shows that emulsification is more severe in hydrocarbon recovery from the heavy crude reservoirs).…”

Factors influencing wettability and surface/interface mechanics of plant surfaces: a review

“…Many studies related to this liquid-liquid floating system have been done from experimental (Burton et al, 2010;Pototsky et al, 2021;Zhao et al, 2023) and theoretical (Phan et al, 2012;Wong et al, 2017;Hack et al, 2020;Ravazzoli et al, 2020;Liu et al, 2021) perspectives. The equilibrium shape of the liquid lens was achieved from experiments, which was attributed to the competition between inertial forces, adhesion forces, and surface tensions.…”