Droplet Formation by Confined Liquid Threads inside Microchannels
نویسندگان
چکیده
A confined liquid thread can form monodisperse droplets near the exit of a microchannel, provided the continuous phase is able to enter the microchannel. A general model that accurately predicts the droplet size including the breakup position inside the microchannel is presented and is verified with experimental observations; breakup occurs as long as the capillary number (Ca) of the liquid thread is below a critical capillary number (Cacr); for cylindrical microchannels, it is derived that Cacr = 1/16. Below Cacr, the formed droplets at the exit of the microchannel have a diameter approximately two times the diameter of the liquid thread; around and above Cacr, the liquid thread remains stable and the formed droplets grow infinitely large. The presented controlled droplet generation method is a useful tool for producing monodisperse emulsions and has great potential for the food and pharmaceutical industry.
منابع مشابه
Formation of Droplets Using Branch Channels in a Microfluidic Circuit
This paper presents a new method for preparing micro droplets inside the liquid layer at a T-junction in a microchannel network. The relations between droplet size, flow speed, and channel size are studied. The droplet size is easily varied by changing the flow conditions in the microchannels. The size distribution of the resulting droplets is very narrow.
متن کاملCapillary threads and viscous droplets in square microchannels
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...
متن کاملSelf-assembly of carbon nanotube polyhedrons inside microchannels.
Well-defined carbon polyhedrons with faceted morphologies and hollow internal structures made of self-organized multi-walled carbon nanotubes have been fabricated by gas phase catalytic CVD inside microchannels, of which the confined space is critical for the formation of polyhedral structures with hexagonal, heptagonal and octagonal cross-sections that show superhydrophobic properties, with th...
متن کاملMicrofluidic Induced Controllable Microdroplets Assembly in Confined Channels
We report on the microfluidic induced monodispersed microdroplet generation and assembly in confined microchannels. Two and three dimensional close-packed droplet lattices were obtained in microfluidic devices by adjusting the channel geometry, the fluidic flow rates and the monodispersed droplet size. The droplet packing was mainly caused by the volumetric effect and capillarity in confined mi...
متن کاملConfined self-assembly of toric focal conic domains (the effects of confined geometry on the feature size of toric focal conic domains).
A smectic liquid crystal (LC) containing a rigid biphenyl group and semifluorinated chains exhibits a high density of toric focal conic domains (TFCDs) arranged in an ordered array when confined within a microchannel. The formation of the TFCDs is strongly influenced by the width (W) and depth (h) of the confined microchannels, most importantly, by the channel depth. We studied a broad variety ...
متن کامل