Tuning the Splitting Behavior of Droplet in a Bifurcating Channel through Wettability–Capillarity Interaction

Abstract

We present a comprehensive computational physics-based study of the influence of surface wettability on the displacement behavior of a droplet in a three-dimensional bifurcating channel. Various surface wettability configurations for the daughter branches are considered to gain insight into the wettability–capillarity interaction. Also, the influence of initial droplet size on the splitting dynamics for different wettability configurations is investigated. Time evolution of the droplet displacement behavior in the bifurcating channel is discussed for different physicochemical parameters including capillary number and wettability. Three distinct flow regimes are identified as the droplet interacts with the bifurcating tip of the channel, namely, splitting, nonsplitting, and oscillating regimes. Furthermore, the occurrence of Rayleigh–Plateau instability in different wettability scenarios is discussed. Additionally, the intricacies associated with the droplet dynamics are elucidated through the temporal evolution of the droplet surface area and mass outflow of the continuous phase. A flow regime map based on the capillary number and wettability contrast of the daughter branches is proposed for a comprehensive description of the droplet dynamics.

Computational and Analytical Investigation of Droplet Impingement and Spreading Dynamics around the Right Circular Cone

“…Boruah et al 48 demonstrated the displacement behavior pair of immiscible fluids flowing through a microfluidic T-junction and concomitantly, the influence of capillarity, wettability, and viscosity ratio on the displacement behavior of the dispersed phase, resulting in squeezing, dripping, necking, droplet formation, and jetting, was described. The splitting behavior of droplets in a Y-shaped bifurcating channel through wettability−capillarity interaction was numerically investigated by Deka et al 49 They also presented regime plots to differentiate the splitting, nonsplitting, and oscillation behaviors of the drop.…”

Triggering the Splitting Dynamics of Low-Viscous Fingers through Surface Wettability Inside Bifurcating Channel

“…Numerous experimental and numerical research works [50][51][52][53] have been done on the splitting dynamics of the droplet into the bifurcating channels. Recently, Dekha et al have performed computation work on the splitting dynamics of the droplet in a Y-shaped channel.…”

Influence of wettability and initial size on the merging dynamics of droplet within a Y-shaped bifurcating channel

“…Baroud et al (2010) and Christophe et al (2009) reported that the merging of droplets is solely driven by interfacial tension between the participating phases and the phenomena can be realized by the instability of the leading interface of the droplet. Some of the recent studies (Deka et al 2020, Schütz et al 2020 explored droplet-based microfluidics to enquire about different phenomena related to droplet splitting and merging which consequences the generation of new droplets. Deka et al (2020) investigated the splitting behavior of droplet in a Y-shaped bifurcating channel governing by inertia of the carrier fluid along with the wettability conditions of the channel walls.…”

“…Some of the recent studies (Deka et al 2020, Schütz et al 2020 explored droplet-based microfluidics to enquire about different phenomena related to droplet splitting and merging which consequences the generation of new droplets. Deka et al (2020) investigated the splitting behavior of droplet in a Y-shaped bifurcating channel governing by inertia of the carrier fluid along with the wettability conditions of the channel walls. The study reveals the fact that the interfacial tension is not only the driving factor for splitting a dispersed droplet at the junction, but the wettability of the channel wall is also one of the vital factor.…”

“…As far as merging dynamics of droplets is concerned, limited numbers of literatures are available considering the wall wettability condition which can potentially influence the dynamics of droplet generation. Deka et al (2020) reported the dynamical behavior of droplet in a Y-shaped bifurcating channel considering both the capillarity and the wettability effects, although the study covers splitting dynamics and not the merging of droplets. The present study aims to investigate the merging dynamics of two identical droplets with different wall wettability condition and the initial dispersed droplet size.…”