Abstract
The breakup behavior of liquid-liquid two-phase flow in a T-junction microchannel was studied by numerical simulation. The continuous phase is the water phase and the discrete phase is the oil phase. The droplet breakup characteristics were studied in a microchannel with a channel width of 0.4 mm, under different continuous phase flow rates (qc = 0.02 m/s, 0.04 m/s, 0.06 m/s, 0.08 m/s, and 0.1 m/s). The two-phase pressure variation during droplet breakup was analyzed. Three types of breakup behavior were observed at the two flow rates: breakup with a permanent tunnel, breakup with a temporary tunnel, and no breakup. The process of droplet breakup is divided into four stages: entry stages, filling stages, stretching stages, and breaking stages. As the qc increases, the droplet breakup time is shortened. This is because the capillary number (Cac) of the continuous phase increases with the increase of qc. The viscous force of the continuous phase increases with the increase of the capillary number, and the shear effect on the droplet is strengthened. The minimum neck width (Wn) and maximum tensile deformation length (Lc) of the droplet increase with the increase of qc. The droplet breakup characteristics in different widths of T-junction microchannels with initial droplet dimensionless length of 1.95 (L/W = 1.95) were studied. Two kinds of breakup behaviors were observed in the study: breakup with a permanent tunnel and breakup with a temporary tunnel. The results indicate that the maximum droplet length and minimum neck width both increase with the channel width. In the case of breakup with a permanent tunnel, the droplet breakup time increases with the increase in channel width. However, in the breakup with a temporary tunnel, the pressure difference caused by plugging is larger, resulting in a shorter breakup time. The droplet breakup characteristics in microchannels with different fork angles (15°, 30°, 45° and 60°) were studied. The results show that the droplet in the Y-junction microchannel is more prone to breakup, but the angle has little effect on the droplet breakup time.
