Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/96241
Title: Experimental observations of flow instabilities and rapid mixing of two dissimilar viscoelastic liquids
Authors: Gan, Hiong Yap
Lam, Yee Cheong
Issue Date: 2012
Source: Gan, H. Y., & Lam, Y. C. (2012). Experimental observations of flow instabilities and rapid mixing of two dissimilar viscoelastic liquids. AIP Advances, 2(4), 042146-.
Series/Report no.: AIP advances
Abstract: Viscoelastically induced flow instabilities, via a simple planar microchannel, were previously used to produce rapid mixing of two dissimilar polymeric liquids (i.e. at least a hundredfold different in shear viscosity) even at a small Reynolds number. The unique advantage of this mixing technology is that viscoelastic liquids are readily found in chemical and biological samples like organic and polymeric liquids, blood and crowded proteins samples; their viscoelastic properties could be exploited. As such, an understanding of the underlying interactions will be important especially in rapid microfluidic mixing involving multiple-stream flow of complex (viscoelastic) fluids in biological assays. Here, we use the same planar device to experimentally show that the elasticity ratio (i.e. the ratio of stored elastic energy to be relaxed) between two liquids indeed plays a crucial role in the entire flow kinematics and the enhanced mixing. We demonstrate here that the polymer stretching dynamics generated in the upstream converging flow and the polymer relaxation events occurring in the downstream channel are not exclusively responsible for the transverse flow mixing, but the elasticity ratio is also equally important. The role of elasticity ratio for transverse flow instability and the associated enhanced mixing were illustrated based on experimental observations. A new parameter Deratio = Deside / Demain (i.e. the ratio of the Deborah number (De) of the sidestream to the mainstream liquids) is introduced to correlate the magnitude of energy discontinuity between the two liquids. A new Deratio-Demain operating space diagram was constructed to present the observation of the effects of both elasticity and energy discontinuity in a compact manner, and for a general classification of the states of flow development.
URI: https://hdl.handle.net/10356/96241
http://hdl.handle.net/10220/10229
ISSN: 2158-3226
DOI: http://dx.doi.org/10.1063/1.4768667
Rights: © 2012 The Author(s). This paper was published in AIP Advances and is made available as an electronic reprint (preprint) with permission of the author(s). The paper can be found at the following official DOI: [http://dx.doi.org/10.1063/1.4768667]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:MAE Journal Articles
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