Mesoscopic analysis of three-dimensional droplet displacement on wetted grooved wall of a rectangular channel

- A three dimensional lattice Boltzmann method is used to investigate the droplet displacement and entrapment of the fluid in a grooved wall microchannel.
- The motion of the droplet is governed by gravity.
- Single and two-groove cases on the channel wall have been considered to study.
- Three different wettability (i.e., hydrophobic, hydrophilic and neutral) of the groove have been considered.
- The prime goal of the study is to investigate % fraction of entrapped droplet fluid inside the groove.

A three dimensional lattice Boltzmann method is used to investigate the droplet displacement and entrapment of the fluid in a grooved wall microchannel under the influence of gravitational force. The groove on the wall is considered to be of different wettabilities in different conditions. The uniform hydrophilic wettability of the channel walls except groove is considered for the study. To incorporate multiphase-multicomponent flow, Shan-Chen model has been used. The study is focused on the effect of the wettabilities of the groove, location of the groove and number of grooves on the displacement and entrapment of the droplet fluid. The analysis shows that the volume of fluid entrapped in the single groove is maximum in hydrophilic surface of the groove. It is also found that when the groove is located on the upper side of the domain, the fraction of entrapped droplet fluid is more compared to the groove located in the middle and lower side of the channel wall. In case of two grooves on the wall, the entrapped fluid is almost double of the single groove case. In all cases, it is observed that the amount of entrapped fluid is maximum in hydrophilic groove and minimum in hydrophobic groove.