Direct measurement of the differential pressure during drop formation in a co-flow microfluidic device

Abstract

In this study, we developed a new method for the direct measurement of differential pressures in a co-flow junction microfluidic device using a Capillary Laplace Gauge (CLG). The CLG - used inside the microchannel device--was designed using a tapered glass-capillary set up in co-flow junction architecture with a three-phase liquid-liquid-gas system with two flowing liquid phases and an entrained gas phase. By taking advantage of the Laplace equation, basic geometric relations and an integrated image analysis program, the movement of the entrained gas phase with the flow of the liquid-phases is tracked and monitored, allowing the gauge to function as an ultra-sensitive, integrated, differential pressure sensor measuring fluctuations in the liquid-dispersed phase channel pressure as small as tens of Pascals caused by droplet formation. The gauge was used to monitor the drop formation and breakup process in a co-flow junction microfluidic device under different flow conditions across a large range (1 × 10(-3) to 2.0 × 10(-1)) of capillary numbers. In addition to being able to monitor short and long term dispersed phase pressure fluctuation trends for both single drop and large droplet populations, the gauge was also used to clearly identify a transition between the dripping and jetting flow regimes. Overall, the combination of a unique, integrated image analysis program with this new type of sensor serves as a powerful tool with great potential for a variety of different research and industrial applications requiring sensitive microchannel pressure measurements.

Formation of liquid–liquid slug flow in a microfluidic T‐junction: Effects of fluid properties and leakage flow

“…Leakage flow at this stage is kept at a high level. With the increasing blockage from the droplet, the leakage flow gradually decreases and the pressure in the continuous phase increases rapidly at this stage, When the interfacial tension cannot balance the accumulated pressure, the droplet neck starts to shrink drastically. During this shrinking stage, a first quick decrease in the estimated Q C is observed because that the assumption of a constant interface curvature in the depth‐wise direction no longer holds.…”

Experiments and modeling on bubble uniformity of Taylor flow in T-junction microchannel

“…The dynamic feedback effects arise from the periodic changes in the hydrodynamic resistance of the microchannel as bubbles enter and exit the system (Glawdel and Ren, 2012). In order to avoid nonuniform bubble sizes, a few measures have been taken: A high resistance feed line has been used to dampen the flow rate fluctuations caused by the syringe pump (Korczyk et al, 2011); surfactants such the SDS (Rajesh and Buwa, 2012) or the Tween-80 (Xu et al, 2014) have been added in liquid to reduce surface tension to mitigate bubble formation pressure changes. Recently, a method has been proposed which attempted to erase the effects of flow rate variations on bubble sizes by improving the channel structure (Dangla et al, 2013;Van Steijn et al, 2013).…”

A review study on micro fluid chips for enhancing the oil recovery by injecting the chemical floods

“…Basically, micro-fluidics is a technical field of study which shows flow passage, flow control and manipulation of liquid substances from large to small volume i. e. micro to nano, micro or macro. It has been broadly used to understand the basic flow behavior in permeable medium for example single phase flow of Newtonian [2] and non-Newtonian [3] fluids, multi-phase flow, cross interface mass-transport and [4] mechanisms of droplet formation [5] coalescence [6]. Also, it is used to assess the polymer effectiveness especially when dealing with pore-scale phenomena due to its advantages such as it is low cost and frequently more illustrative of the medium than modelling.…”