Colloidal behavior of aqueous montmorillonite suspensions in the presence of non-ionic polymer

In this paper we characterized at first, the rheological behavior of the bentonite suspensions and the aqueous solutions of polyethylene oxide (PEO), then we were investigated the influence of this polymer in a water-based drilling fluid model (6% of bentonite suspension). The objective is to exhibit how the non ionic polymer with molecular weight 6×103 g/mol. of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions. The rheological measurements made in simple shear and in dynamic on the mixture (water-bentonite-PEO), showed rheological properties of bentonite suspensions both in the presence and absence of non-ionic polymer. The PEO presents an affinity for the bentonite particles slowing down their kinetic aggregation. The analysis by X-rays diffraction also allowed understanding the structure of this mixture. It had revealed the intercalation between of the clay platelets on one hand, and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel- Bulkley rheological model is used for the correlation of our experimental result

Etude de la convection forcée d’un fluide non-Newtonien dans un espace annulaire tournant

Nous proposons une étude numérique de la convection thermique des fluides non-newtoniens dans les espaces annulaires cylindriques tournants. Le modèle rhéologique retenu dans cette étude est le modèle de Carreau. Les équations de conservation sont résolues par une méthode d’éléments finis mixtes. On étudie l’influence du nombre de Reynolds et de l’indice de l’écoulement, sur le transfert de chaleur et sur la structure de l’écoulement. Les résultats obtenus en convection forcée sont discuté

Rheological characterization of the systems clay-polymer. Drilling fluids application.

cited By 0International audienceIn this article, we demonstrate how the non ionic polymer, the polyethylene oxide (PEO) with molecular weight 6000 g/mol of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions (6%) in the water. The different rheological tests made in simple shear and in dynamic on the ternary system (water-bentonite-PEO), showed the influence of the polymer on the rheological properties of this drilling fluid. The PEO which presents an affinity for the bentonite particles slows down the kinetic of aggregation of the clay particles. Also the analysis by X-rays diffraction on different samples revealed the intercalation of the clay platelets on one hand and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel-Bulkley rheological model is used for the correlation and the interpretation of our experimental results. © (2011) Trans Tech Publications

Numerical study of a thermodependent non-Newtonian fluid flow between vertical concentric cylinders

In this paper, we present a numerical investigation of the thermal convection for a thermodependent non-Newtonian fluid in an annular space between two coaxial rotating cylinders. The rheological behaviour of the fluid can be expressed through the Ostwald-De-Waele power law: View the MathML sourceτ=Kγ˙n; all fluid properties except consistency index K are constant. K–T relation used is K = K0e−bT. The problem is studied when the heated inner cylinder is rotating around the common axis with constant angular velocity and the cooled outer cylinder is at the rest. The horizontal endplates are assumed adiabatic. The governing equations are solved using mixed finite elements method. The influence of the temperature on the structure of the dynamic and thermal fields is examine

Finite element study of mixed convection for non-Newtonian fluid between two coaxial rotating cylinders

In this work, we present a numerical simulation of the flow characteristics and the heat transfer mechanism of a non-Newtonian fluid in an annular space between two coaxial rotating cylinders. The Carreau stress–strain relation was adopted to model the rheological fluid behaviour. The problem is studied when the heated inner cylinder rotates around the common axis with constant angular velocity and the cooled outer cylinder is at the rest. The horizontal endplates are assumed adiabatic. The governing equations are solved using mixed finite elements method. The effects of the different parameters on the heat transfer and on the flow are examined. These parameters are the Reynolds (Re), the Grashof (Gr) and the Weissenberg numbers (We), and the flow index (n). The results of the natural, forced and mixed convections are presented and discussed. © 2006 Elsevier Ltd. All rights reserve

Rheological study of concentrated dispersions. Application to the drilling fluid.

International audienceIn order to understand the rheological behavior of concentrated aqueous Algerian bentonite dispersions of drilling (sodium bentonite of Mostaganem "m'zila"), rheological tests were carried out. By varying the concentration of bentonite, flow tests have allowed to estimate the yield stress and apparent viscosity for each concentration and to see their influence on the rheological behavior of these dispersions. In addition dynamic tests (oscillatory) are used to define the linear region of our samples, the state of our fluid (elastic solid or viscous liquid) and understanding the mechanisms of structuring of the particles constituting the material. In parallel, other tests coupled with rheological measurements such as x-rays diffraction to know the mineralogical composition and granulometry to estimate the bentonite particle size