Abstract
In this paper, we studied the effects of the intersection angle between the inlet channels on the droplet diameter using a COMSOL Multiphysics® simulation. We employed the level-set method to study the droplet generation process inside a microfluidic flow device. A flow-focusing geometry was integrated into a microfluidics device and used to study droplet formation in liquid–liquid systems. Droplets formed by this flow-focusing technique are typically smaller than the upstream capillary tube and vary in size with the flow rates. Different intersection angles were modeled with a fixed width of continuous and dispersed channels, orifices, and expansion channels. Numerical simulations were performed using the incompressible Navier–Stokes equations for single-phase flow in various flow-focusing geometries. As a result of modeling, when the dispersed flow rate and the continuous flow rate were increased, the flow of the continuous flow fluid interfered with the flow of the dispersed flow fluid, which resulted in a decrease in the droplet diameter. Variations in the droplet diameter can be used to change the intersection angle and fluid flow rate. In addition, it was predicted that the smallest diameter droplet would be generated when the intersection angle was 90°.
Highlights
In recent years, droplet generation in microfluidic channels has become a useful technical platform for diverse applications in the areas of biology, biomedical studies, chemical synthesis, and drug discovery [1,2]
Results and Discueqsusiiloibnrium of the shear force of the continuous phase flow, we assumed that the droplet diameter could be expressed as follows [29]: We analyzed the effect of the ratio variation for vc/vd on the diameter of the droplets, the number of droplets, and the representativded d=rok(pleQt dgen+erλactoiot nθ)pαCaatβte, rns for the systems (8)
Monitoring how the droplet diameter changed when the flow rate ratios increased allowed us to determine the dominant mode of break-up
Summary
Droplet generation in microfluidic channels has become a useful technical platform for diverse applications in the areas of biology, biomedical studies, chemical synthesis, and drug discovery [1,2]. Microscale droplets of liquid can be produced with high throughput and great uniformity when two immiscible fluids are introduced into droplet generation devices, which can be classified into several types: co-flow (coaxial), cross-flow (including T-junctions), and flow-focusing (FF) devices [3]. ‘continuous or continuous phase flow’ denotes a fluid that allows droplets to flow continuously, while ‘dispersed or dispersed phase flow’ denotes a droplet to be made in a fluid that flows discontinuously. Droplet generation in biochemical processes, as well as in molecular biology processes is very useful, such as in the encapsulation of cells or drugs including cosmetic ingredients
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