Droplet-based microfluidics has received extensive research interests due to its superior control over the fluid flow. Conventional passive microfluidic flow-focusing devices confront difficulties in controlling droplet sizes in dripping regime especially when the dispersed phase has a large viscosity. External electric fields have been reported as an effective tool to manipulate droplet breaku...

One particularly efficient approach to making emulsions having monosized droplets is to push a fluid through an orifice into a transverse flow of a second immiscible fluid. We find that, at an intermediate particle Reynolds number, the final droplet size can be readily computed using a simple force balance. Remarkably like the well-known dripping faucet, this system displays both dripping and j...

We experimentally study the formation and evolution of threads containing more viscous liquids surrounded by less viscous, immiscible liquids through hydrodynamic focusing in square microchannels. Over a large range of viscosities and interfacial tensions, five characteristic regimes of flow behavior are identified: threading, jetting, dripping, tubing, and displacement. We locate the boundarie...

The dripping faucet experiment has been performed multiple times since it was proposed by Robert Shaw in 1984 as a system exhibiting chaos. It continues to serve as a relatively simple chaotic system for numerical and experimental analysis. This project seeked to replicate past experiments and find the route to chaos in droplet formation. It was desired to collect enough data to construct a bif...

The objective of this research work is to propose a phase diagram that can be used find proper operating condition for generating droplets different types. It found the QR versus CaD effectively classify droplet generation into three vivid regimes: dripping, jetting and tubing. For dripping regime, its in range either < 10−4 50 or 10−3 1. 1.35 × 10−2 > 100 tubing

We report observation and manipulation of a capillary jet under ultra-high centrifugal gravity in a proposed capillary-based fluidic device for the synthesis of microparticles in a centrifugal tube called Centrifuge-Based Droplet Shooting Device (CDSD). Using a high-speed camera, we directly observed the dripping to jetting transition of a viscous capillary jet of water and Sodium alginate solu...

We examine the dynamics of laser droplet generation that is dependent on the detachment pulse power. In the absence of the detachment pulse, undulating pendant droplets are formed at the end of a properly fed metal wire due to the impact of the primary laser pulse that induces melting. Eventually, these droplets detach, i.e. overcome the surface tension, because of their increasing mass. We sho...

This work is focused on the mechanisms of dripping and jetting flow modes viscoelastic semi-dilute polyacrylamide aqueous solutions co-flowing with silicone oil in co-axial capillaries. A phase diagram dripping, jetting, intermediate established. It was found that mode, elongation velocity filament between terminal droplet inner capillary controlled solely by continuous rate. At same time, decr...

Liquid agent transport was investigated around unheated and heated horizontal cylinders (to a near-surface temperature of approximately 423 K, i.e., well above the water boiling point) under ambient conditions. Experimental results are presented for a well-characterized, droplet-laden homogenous turbulent flow field, using water, methoxy-nonafluorobutane (i.e., HFE-7100, C4F9OCH3, with a boilin...

We demonstrate the control of droplet sizes by an ac voltage applied across microelectrodes patterned around a flow-focusing junction. The electrodes do not come in contact with the fluids to avoid electrochemical effects. We found several regimes of droplet production in electric fields, controlled by the connection of the chip, the conductivity of the dispersed phase and the frequency of the ...