Evolution of two-phase flow in networks of branching microchannels

Abstract : The transport of liquid plugs in networks of branching channels is experimentally studied. Liquid plugs are pushed at different driving conditions in a tree-like network of microchannels with widths either narrowing or widening with the generation number. The global flow pattern can be either symmetric or asymmetric, with daughter plugs dividing in synchrony or asynchrony as a function of the driving force and the network geometry. This behavior is explained by plug interactions at work in a fundamental element of the network, which consists of three adjacent bifurcations. When a single plug is pushed at constant pressure, its daughters can reach the exits only if the driving pressure is higher than the thresholds in the network. For a plug pushed at constant flow rate, its daughters can arrive at the exits of the narrowing network even when the flow rate is low. Conversely, in the widening network, only some daughters can reach the exits while others get stuck at intermediate bifurcations. Moreover, a linear relation between the driving pressure and total flow rate in the network is derived and found to be applicable in the presence of successive plugs. In this case, the total flow rate can be influenced by the initial distance between plugs when the driving pressure and plug lengths are fixed. Furthermore, some preliminary results about network reopening through plug ruptures at high pressure driving are also presented.
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Mechanics of the fluids [physics.class-ph]. Ecole Polytechnique X, 2010. English


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Contributor : Yu Song <>
Submitted on : Saturday, April 16, 2011 - 2:05:05 PM
Last modification on : Friday, May 20, 2011 - 10:40:35 AM

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  • HAL Id : pastel-00585509, version 1

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Yu Song. Evolution of two-phase flow in networks of branching microchannels. Mechanics of the fluids [physics.class-ph]. Ecole Polytechnique X, 2010. English. <pastel-00585509>

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