Showing papers on "Shear thinning published in 1974"
TL;DR: In this article, a dimensionless number has been formulated to correlate the permeability reduction factor with the polymer, brine, and rock properties, and a model has been developed to represent adsorption as a function of polymer and brine properties.
Abstract: The rheological behavior of the flow of polymer solution through porous media could be Newtonian at low flow rates, pseudoplastic at intermediate flow rates, and dilatant at high flow rates. The pseudoplastic behavior is modeled with the Blake-Kozeny model for power law model fluids. The dilatant behavior is modeled with the viscoelastic properties of the polymer solution. The reduction in permeability is postulated to be due to a trapped or adsorbed layer of polymer molecules that either plugs or reduces the effective size of the pores. A dimensionless number has been formulated to correlate the permeability reduction factor withthe polymer, brine, and rock properties. This dimensionless number represents the ratio of the size of the polymer molecular coil to an effective pore radius of the porous medium. A model has been developed to represent adsorption as a function of polymer, brine, and rock properties. The model assumes that the polymer is absorbed on the surface of the porous medium as a monolayer of molecular coils that have a segment density only slightly greater than the molecular coil in dilute solution. (25 refs.)
301 citations
01 Aug 1974
TL;DR: A theory was developed in this paper to predict pseudoplastic flow behavior for agglomerated suspensions, but the quantitative correlation between theory and experiment is not satisfactory, as shown in Figure 1.
Abstract: Small amounts of a second immiscible liquid, water, were introduced into suspensions of glass beads (untreated or surface treated with dimethyldichlorosilane) in liquid polybutadiene. Water formed liquid bridges between the particles and caused the suspensions containing untreated beads to agglomerate. These large agglomerates changed the flow behavior from Newtonian to pseudoplastic. The extrapolated Bingham yield stress went through a maximum as the amount of water increased. Surfactants first decrease the pseudoplastic behavior and then, at higher concentrations, surfactants cause the suspensions to become Newtonian in behavior. A theory was developed in an attempt to explain the experimental results. The theory predicts pseudoplastic flow behavior for agglomerated suspensions, but the quantitative correlation between theory and experiment is not satisfactory.
50 citations
TL;DR: In this article, the authors used the wetted sphere technique for the measurement of diffusivity of gases in polymeric solutions under flow conditions and showed that gas absorption from a stress-free interface may not be a sensitive technique of studying shear rate dependence of D.
39 citations
TL;DR: In this article, the volumetric filler fraction ranges between 0.01 and 0.07 and the shear rate from 0.1 to 1000 sec−1, and the results indicate that the filler enhances the non-Newtonian pseudoplastic behaviour of the suspending solution increasing its relaxation time.
20 citations
TL;DR: In this paper, the authors used the modified Martin equation to describe the effect of concentration, and the Sabia equation is used to describe pseudoplastic behavior, and they showed that at constant stress the activation energies (EA) for the effects of temperature on viscosity are higher for solutions in the midrange of composition than for either of the pure components.
Abstract: The steady shear viscosities of high density polyethylene disolved in highly branched isoparaffin solvents have been measured with a high-pressure autoclave viscometer at temperatures ranging from 150 to 250°C and over a range of shear rates from 0.02 to 170 sec−1. Laboratory measurements on solutions ranging from 15 to 67 wt percent polymer were used to develop and calibrate a mathematical model for solution viscosity intended for a range of from 10 to 100 wt percent polymer. The foundation for the model consists fo two equations: the modified Martin equation is used to describe the effect of concentration, and the Sabia equation is used to describe pseudoplastic behavior. The model correlates viscosities that can range over nine orders of magnitude with sufficient accuracy for most process design work, averaging less than 10 percent error. Both the data and the model indicate that at constant stress the activation energies (EA) for the effect of temperature on viscosity are higher for solutions in the midrange of composition than for either of the pure components. This peak in EA is related to the density difference between polymer and solvent.
7 citations
TL;DR: In this article, the effects of nonionic surfactants on thin-film flow of pseudoplastic non-Newtonian liquids down a smooth vertical plate have been studied experimentally.
Abstract: The effects of nonionic surfactants on thin-film flow of pseudoplastic non-Newtonian liquids down a smooth vertical plate have been studied experimentally. For all liquids examined there was a surfactant concentration at which the stabilizing action of surfactants was maximized. Comparison with experimental data showed that an existing equation, developed for the stabilizing action of surfactants on thin-film flow of Newtonian fluids, may be used to predict the effect of surfactants on the stability of pseudoplastic thin-film flow by using the zero-shear rate apparent viscosity in place of the Newtonian viscosity.
6 citations
TL;DR: In this article, an experimental and analytical study has been conducted on thin film flow of pseudoplastic, non-Newtonian liquids down a smooth vertical plate and mean film thickness, friction coefficient, wavelength and entrance length preceding the first noticeable waves have been examined experimentally.
5 citations