(236e) Dynamic Blocking of Water-Hydrocarbon Emulsion Flow In Microchannel

Water-hydrocarbon emulsions are widely used in various oil–production processes, for example for blocking drill holes and managing fluid flows. With respect to well-known hydrodynamic/rheological properties, the typical distinctive feature of such emulsions is their greater viscosity and non-Newtonian behavior as compared to that of carrier liquid.  However, the flow of emulsions in capillary structures and microchannels reveals a remarkable, quite unexpected effect called “dynamic blocking”, whereby the flow of emulsion through microchannel ceases with the time despite the presence of a continuous pressure gradient. The term “dynamic blocking” reflects the fact that, despite an apparent arrest of the flow, it can nevertheless be observed on a microscopic scale at a much lower (by three to four orders of magnitude) flow rate and with a significantly modified structure of microflows. It should be noted that the size of water microdrops is significantly (by more than an order of magnitude) smaller than the characteristic size of the channel. No clear understanding exists today that explains the behavior of emulsions as they move through the microstructure. In this paper some experimental results of “dynamic blocking” will be presented, and some plausible mechanisms explaining its physical nature will be discussed. This research is supported by the Grant of the Ministry of Education and Science of the Russian Federation (G34.31.0040).