Rheological properties of high concentrations of carboxymethyl cellulose solutions

Edali, Mohamed; Esmail, M. N.; Vatistas, Goergios H.

doi:10.1002/1097-4628(20010307)79:10<1787::aid-app70>3.0.co;2-2

Cited by 89 publications

(66 citation statements)

References 9 publications

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“…2 the rheological curves for the CMC solution used in the present experiment. It is worthy to note that viscoelastic effects are already observed with the adopted concentration, as reported in [25,26]. From velocity measurements and from the curve η(γ ) we deduce the corresponding value of the viscosity for the CMC solution and, then, we prepare an appropriate Glycerol solution, which matches the calculated non-Newtonian viscosity.…”

Section: Choice Of a Non-newtonian Fluid And Scaling Argumentmentioning

confidence: 68%

“…Dynamic viscosities of the distilled water and the Glycerol solution are measured using a falling ball viscometer at a room temperature of about 20 • C. The shear thinning fluid used in the present experiments is an aqueous solution of carboxymethyl cellulose (CMC), which is a nontoxic water soluble polymer of sodium salt (CH 2 COONa). The rheological response to steady-state shear flow test for the CMC can be modeled by the power law Ostwald-de-Waele equation written as [25,26]:…”

Section: Experimental Apparatusmentioning

confidence: 99%

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Large-scale flow structures in particle–wall collision at low Deborah numbers

Guala

Stocchino

2007

European Journal of Mechanics - B/Fluids

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PIV measurements of two dimensional velocity fields during the rebound of a steel spherical particle colliding a wall are provided in Newtonian fluids (distilled water and aqueous solution of Glycerol) and in a viscoelastic shear thinning fluid (aqueous solution of carboxymethyl cellulose). The experiments are designed in order to reproduce the same conditions in which the coefficient of restitution was observed to be significantly affected by viscoelasticity at the typical scales of the lubrication layer [A. Stocchino, M. Guala, Particle-wall collision in shear thinning fluids, Exp. Fluids 65 (2005) 17-46]. In such conditions, the Deborah number, which is a measure of the relevance of the viscoelastic effects compared to the inertial effects, is however relatively low. The aim of the present study is to investigate the relative influence of the elasticity and of the shear thinning character of the nonNewtonian fluid on the large scale flow structures triggered by the particle impact. Special attention is dedicated to the definition of a proper viscosity when the non-Newtonian fluid is involved. In this respect, a scaling argument is suggested to derive the value of the viscosity for an assigned rate of strainγ , given a constitutive law of the kind τ = τ (γ ), where τ is the shear stress. The scaling analysis is supported by previous works on particle settling in non-Newtonian fluids and by recent studies on the flow structures that form as a consequence of a particle-wall collision in Newtonian fluids. The experimental validation of the proposed scaling is provided by first choosing a Newtonian fluid with viscosity equal to the non-Newtonian viscosity and, then, carrying out a comparative analysis of the large-scale vortical structure formed during the collision-rebound process. The statistical analysis suggests that the large scale flow structures observed during the Glycerol experiment and the CMC solution experiment behaves similarly in term of spatial and temporal scales. Therefore, at least for the values of the dimensionless parameters investigated, the shear thinning character of the non-Newtonian fluid employed is dominant with respect of its viscoelasticity.

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Section: Choice Of a Non-newtonian Fluid And Scaling Argumentmentioning

confidence: 68%

Section: Experimental Apparatusmentioning

confidence: 99%

Large-scale flow structures in particle–wall collision at low Deborah numbers

Guala

Stocchino

2007

European Journal of Mechanics - B/Fluids

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“…Homotopy analysis method (HAM) is an effective approach in solving the nonlinear differential equations, which was proposed and developed by Liao. [39][40][41] Considering the basic essentials of HAM, we present here only the main structure of the computations.…”

Section: Application Of Homotopy Analysis Methods In the New Modelmentioning

confidence: 99%

“…The generalized power law diffusion model has been utilized to address some typical nonlinear diffusion processes such as shear flow and heat transfer of non-Newtonian power law fluids by Zheng 36 and Pascal et al 37,38 The advantage that such theories can characterize the typical shear-thinning and shear-thickening performances of non-Newtonian fluids by modulating the power exponent n adequately, while the rheological relationships of some real complex fluids such as carboxymethyl cellulose (CMC) solutions and polyvinyl alcohol (PVA) were used to verify the value range of n experimentally. [39][40][41][42] With such motivation, we introduce in this work a generalized nonlinear diffusion model to remodel the rheological and heat-conduction constitutive relations of a micropolar fluid. The model first shows the effects of shear-thinning on boundary layer flow and heat transfer theoretically by analyzing the salient parameters in detail.…”

Section: Introductionmentioning

confidence: 99%

A novel investigation of a micropolar fluid characterized by nonlinear constitutive diffusion model in boundary layer flow and heat transfer

et al. 2017

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The rheological and heat-conduction constitutive models of micropolar fluids (MFs), which are important non-Newtonian fluids, have been, until now, characterized by simple linear expressions, and as a consequence, the non-Newtonian performance of such fluids could not be effectively captured. Here, we establish the novel nonlinear constitutive models of a micropolar fluid and apply them to boundary layer flow and heat transfer problems. The nonlinear power law function of angular velocity is represented in the new models by employing generalized "n-diffusion theory," which has successfully described the characteristics of non-Newtonian fluids, such as shear-thinning and shear-thickening fluids. These novel models may offer a new approach to the theoretical understanding of shear-thinning behavior and anomalous heat transfer caused by the collective micro-rotation effects in a MF with shear flow according to recent experiments. The nonlinear similarity equations with a power law form are derived and the approximate analytical solutions are obtained by the homotopy analysis method, which is in good agreement with the numerical solutions. The results indicate that non-Newtonian behaviors involving a MF depend substantially on the power exponent n and the modified material parameter K 0 introduced by us. Furthermore, the relations of the engineering interest parameters, including local boundary layer thickness, local skin friction, and Nusselt number are found to be fitted by a quadratic polynomial to n with high precision, which enables the extraction of the rapid predictions from a complex nonlinear boundary-layer transport system. Published by AIP Publishing.

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“…Previous studies indicated that the preparation of CMC solutions requires a minimum time to fully dissolve the CMC powder, depending on the polymer concentration and the temperature (Edali et al 2001;Savadkoohi et al 2013a). Therefore, PSCMC, LMCMC and HMCMC dispersions (0.5, 1, 3, 5 and 7 % w/w) were prepared by dissolving the powder in deionized water at neutral pH and ambient temperature.…”

Section: Methodsmentioning

confidence: 99%

Small deformation viscoelastic and thermal behaviours of pomegranate seed pips CMC gels

Savadkoohi

Farahnaky

2014

J Food Sci Technol

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The current investigation presents an exploration in phase behaviour of carboxymethyl cellulose (CMC) produced from pomegranate seed pips compared to low and high viscosity CMCs (LMCMC and HMCMC) primarily at low solid concentrations. Cellulose was extracted with 10 % NaOH at 35°C for 22 h from pomegranate seed pips and converted to CMC by etherification process. Thermomechanical analysis and micro-imaging were carried out using small deformation dynamic oscillation in shear, modulated differential scanning calorimetry (MDSC) and scanning electron microscopy (SEM). The results emphasize the importance of molecular interaction and the degree of substitution in produced CMC. Thermal gravimetric analysis (TGA) thermograms showed an initial weight loss in pomegranate seed pips CMC (PSCMC) sample, which we attribute to presence of amount of moisture in sample powder. MDSC analysis of PSCMC showed five different peaks at 84, 104, 173, 307 and 361°C. Moreover, G' and G" changes were found to be dependent on both concentration and frequency. The results of frequency sweep and tan δ indicate that PSCMC solutions can be classified as weak gels.

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Rheological properties of high concentrations of carboxymethyl cellulose solutions

Cited by 89 publications

References 9 publications

Large-scale flow structures in particle–wall collision at low Deborah numbers

Large-scale flow structures in particle–wall collision at low Deborah numbers

A novel investigation of a micropolar fluid characterized by nonlinear constitutive diffusion model in boundary layer flow and heat transfer

Small deformation viscoelastic and thermal behaviours of pomegranate seed pips CMC gels

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