TY  - EJOU
AU  - Yin, Zongjun 
AU  - Su, Rong 
AU  - Xu, Hui 

TI  - Numerical Simulation of Droplet Generation in Coaxial Microchannels
T2  - Fluid Dynamics \& Materials Processing

PY  - 2024
VL  - 20
IS  - 3
SN  - 1555-2578

AB  - In this study, numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics (level-set method). Four flow patterns, namely “drop flow”, “jet flow”, “squeeze flow”, and “co-flow”, have been obtained for different flow velocity ratios, channel diameter ratios, density ratios, viscosity ratios, and surface tension. The flow pattern map of two-phase flow in coaxial microchannels has been obtained accordingly, and the associated droplet generation process has been critically discussed considering the related frequency, diameter, and pinch-off length. In particular, it is shown that the larger the flow velocity ratio, the smaller the diameter of generated droplets and the shorter the pinch-off length. The pinch-off length of a droplet is influenced by the channel diameter ratio and density ratio. The changes in viscosity ratio have a negligible influence on the droplet generation pinching frequency. With an increase in surface tension, the frequency of generation and pinch-off length of droplets decrease, but for small surface tension the generation diameter of droplet increases.
KW  - Droplet generation characteristics; coaxial microchannels; flow patterns; pinch-off length

DO  - 10.32604/fdmp.2023.042631