The role of shear and elongation in the flow of solutions of semi-flexible polymers through porous media |
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Authors: | Juan M González Alejandro J Müller Miguel F Torres A Eduardo Sáez |
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Institution: | (1) Grupo de Polímeros USB, Departamento de Ciencias de los Materiales, Universidad Simón Bolívar, Caracas, 1080A, Venezuela;(2) Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA |
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Abstract: | The rheological behavior of hydrophobically modified hydroxyethyl cellulose (HMHEC) and xanthan gum solutions has been characterized in simple shear flow, opposed-jets flow, and flow through porous media. Both polymers exhibit shear thinning in simple shear flow and apparent shear thinning in flow through porous media. Analysis of the results shows there is a direct correspondence between shear viscosities determined in simple shear experiments and apparent viscosities in porous media flow at relatively low shear rates. At high shear rates the extensional component of the flow in porous media appreciably increases the apparent viscosity over the simple shear values. This increase is shown to correlate with results obtained in opposed-jets experiments, and is attributed to formation of transient entanglements. |
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Keywords: | Hydrophobically modified hydroxyethyl cellulose Xanthan gum Porous media |
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