Rheological behaviour of dextran sulfate solutions

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Asgar Farahnaky ◽  
Zahra Allahdad ◽  
Mahmoud Aminlari ◽  
Mahsa Majzoobi ◽  
Hamed Askari ◽  
...  
Keyword(s):  
Dextran Sulfate ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Newtonian Flow ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
Sulfate Solutions ◽  
Different Temperatures ◽  
Power Law Equation ◽  
Plate Geometry

Abstract The purpose of this research was to study the rheological behaviour of dextran sulfate solutions under different conditions. A PC controlled rotational viscometer with a cone and plate geometry equipped with a temperature controlled unit was used to measure apparent viscosity of dextran solutions at different temperatures (25, 40 and 60 oC) and concentrations (2, 5, 10 and 20%). Viscosity tests of dextran sulfate solutions were performed at a range of shear rates (8-230 1/s) and the rheological data were fitted using the Power Law equation to get consistency and flow behaviour indices. The results indicated that all dextran sulfate solutions showed Newtonian flow behaviour. The viscosity of dextran sulfate solutions was significantly affected by temperature, e.g. the viscosity of a 5% solution at 25, 40 and 60 oC was 16.7, 12.7 and 10.7 mPa.s, respectively.

Rheological Characterisation of Heavy Oil and Impact on its Production Enhancement

2011 ◽  
Vol 367 ◽  
pp. 393-401 ◽  
Author(s):  
Amol Bali ◽  
Babs Mufutau Oyeneyin ◽  
Ebenezer Adom
Keyword(s):  
Power Law ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Horizontal Well ◽  
Rheological Behaviour ◽  
Pvt Properties ◽  
Rheological Models ◽  
Bingham Plastic ◽  
Shear Rates ◽  
Different Temperatures

Criticality of rheology for heavy oil recovery is the main purpose of this paper supported by different results. The Bingham Plastic, Power Law and Herschel Bulkley rheological models have been adopted for the purpose of this paper. Rheological characterisation was carried out for different temperatures. Rheological behaviour of non-Newtonian heavy oil for different shear rates is analysed in this paper. Effective shear and bulk viscosities for different flow rates are compared for all rheological models. Using the horizontal well productivity model, the drawdown values for all rheological models are determined. Similarly for the sand management purpose the critical rates of Newtonian and these three non-Newtonian fluids are plotted to determine the critical drawdown values for each type of fluid. Impact of drainage profile on the effective viscosities is also compared for different drainage profiles. Shear rate models are proposed in this paper for Bingham Plastic, Power Law and Herschel Bulkley rheological models. The new Micro-PVT equipment is also introduced for determining the PVT properties and rheological behaviour of heavy oil. Nomenclature

scholarly journals Rheological Behavior of Sumac (Rhus coriaria L.) Extract as Affected by Temperature and Concentration and Investigation of Flow Behavior with CFD

2020 ◽  
Vol 10 (6) ◽  
pp. 7120-7134
Keyword(s):  
Arrhenius Equation ◽  
Flow Behavior ◽  
Rheological Behaviour ◽  
Effect Of Temperature ◽  
Sudden Expansion ◽  
Flow Properties ◽  
Rotational Viscometer ◽  
Different Temperatures ◽  
Rhus Coriaria ◽  
Temperature Ranges

The purpose of this study is to investigate the rheological properties of sumac extract in different concentrations at different temperatures as well as its flow behavior in sudden expansion-contraction and at 90o elbow with CFD. The rheological behaviour of sumac extract in different concentrations (45.65%, 50.44%, 55.53%, 60.32%, and 65.13% total solids) were evaluated using a rotational viscometer at different temperatures (10, 20, 30, 40 and 50 C). Sumac extract samples showed Newtonian flow properties in these temperature ranges. Arrhenius equation was used to determine the effect of temperature. Ea value varied in the range of 11.16-34.35 kJ/mol, which diminished with a decrease in concentration. Power and Exponential models were used to characterize the effect of concentration on flow behavior. Time average velocity vector and contours, vorticity contours, kinetic energy contours, and pressure contours are given to show the flow behavior of sumac extract.

Constitutive Models for AZ31 Magnesium Alloys

2008 ◽  
Vol 367 ◽  
pp. 87-94 ◽  
Author(s):  
Carlo Bruni ◽  
Lorenzo Donati ◽  
Mohamad El Mehtedi ◽  
M. Simoncini
Keyword(s):  
Magnesium Alloy ◽  
Constitutive Models ◽  
Extrusion Process ◽  
Flow Behaviour ◽  
Az31 Magnesium Alloy ◽  
Strain Rates ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Different Temperatures ◽  
Power Law Equation

The present investigation aims at studying and modelling the flow behaviour of the AZ31 magnesium alloy by means of torsion tests performed in extended ranges of temperature and strain rates. Two types of rheological models were considered. The former is based on the power law equation, whilst the latter is based on the Sellars and Tegart approach. The effectiveness of the two constitutive models in describing the flow behaviour of the AZ31 magnesium alloy under investigation was evaluated. It was observed that both the equations are able to predict the flow behaviour of the material at different temperatures and strain rates. In particular, the former is very effective in predicting the hardening stage of the flow curve, whilst the latter allows to fit the softening stage. The models were used for the finite element analysis of a complex extrusion process and the results, in terms of the load-stroke curves, compared to each other.

scholarly journals Viscosity Model for Nanoparticulate Suspensions Based on Surface Interactions

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2752
Author(s):  
Benedikt Finke ◽  
Clara Sangrós Sangrós Giménez ◽  
Arno Kwade ◽  
Carsten Schilde
Keyword(s):  
Mechanistic Model ◽  
Model Development ◽  
Rheological Behaviour ◽  
Hybrid Modelling ◽  
Shear Rates ◽  
Drag Forces ◽  
Boehmite Nanoparticles ◽  
Data Points ◽  
Two Parameters ◽  
Physical Phenomena

In this paper, a widely mechanistic model was developed to depict the rheological behaviour of nanoparticulate suspensions with solids contents up to 20 wt.%, based on the increase in shear stress caused by surface interaction forces among particles. The rheological behaviour is connected to drag forces arising from an altered particle movement with respect to the surrounding fluid. In order to represent this relationship and to model the viscosity, a hybrid modelling approach was followed, in which mechanistic relationships were paired with heuristic expressions. A genetic algorithm was utilized during model development, by enabling the algorithm to choose among several hard-to-assess model options. By the combination of the newly developed model with existing models for the various physical phenomena affecting viscosity, it can be applied to model the viscosity over a broad range of solids contents, shear rates, temperatures and particle sizes. Due to its mechanistic nature, the model even allows an extrapolation beyond the limits of the data points used for calibration, allowing a prediction of the viscosity in this area. Only two parameters are required for this purpose. Experimental data of an epoxy resin filled with boehmite nanoparticles were used for calibration and comparison with modelled values.

VISCOSITY OF NATURAL RUBBER SOLUTIONS AT VERY LOW RATES OF SHEAR

1957 ◽  
Vol 35 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Morton A. Golub
Keyword(s):  
Experimental Data ◽  
Natural Rubber ◽  
Pressure Head ◽  
Viscosity Data ◽  
Theoretical Relation ◽  
Newtonian Flow ◽  
Shear Rates ◽  
Reduced Viscosity ◽  
Wide Range ◽  
Composite Data

The shear dependence of viscosity of benzene solutions of natural rubber was studied at rates of shear from about 500 down to less than 1 sec.−1. Measurements involved following the change of pressure head with time of the various solutions flowing in a capillary, U-tube viscometer. Curvature in the plots of the logarithm of pressure head versus time indicated non-Newtonian flow. From such curves, reduced viscosity data over the above-mentioned shear range were readily derived. As a check, data over the range 100–500 sec.−1 were also obtained with a five-bulb viscometer of the Krigbaum–Flory type, and these data overlapped those obtained with the U tube. The reduced viscosity increased very sharply with decrease in gradient, making extrapolation to the viscosity axis quite unreliable. However, a theoretical relation proposed by Bueche fitted the composite data rather well. This work furnished a nice technique for determining the zero shear reduced viscosity (ηap/c)0 without the necessity of performing an uncertain extrapolation: evaluate the parameters of the Bueche formula which best satisfies the experimental data over a fairly wide range of shear rates, and then calculate (ηap/c)0 directly.

Rheological Properties of Tomato Concentrate

2008 ◽  
Vol 4 (7) ◽  
Author(s):  
Manish Dak ◽  
Radha Charan Verma ◽  
S N A Jaaffrey
Keyword(s):  
Rheological Properties ◽  
Absolute Temperature ◽  
Power Law Model ◽  
Arrhenius Model ◽  
Rotational Viscometer ◽  
Consistency Coefficient ◽  
Flow Behaviour Index ◽  
Different Temperatures ◽  
Wide Gap ◽  
Good Agreement

Rheological properties of tomato concentrate were evaluated using a wide-gap rotational viscometer (Brookfield Engineering Laboratories: Model LVDV-II) at different temperatures of 20, 30, 40, 50, and 60oC, at concentration of 18, 12.18 and 8.04 % total solids, and at appropriate shear rate(1-100 RPM). The power law model was fitted to the experimental results. The values of flow behaviour index (n) were found less than unity (0.23 to 0.82) at all the temperature and the concentration indicating shear-thinning (pseudoplasticity) behaviour of the concentrate. The correlation between the observed consistency coefficient ranging from 0.09 to 65.87 Pa.sn and the inverse absolute temperature has been exhibited by Arrhenius model. Consistency coefficient increased exponentially with increase in the concentration. Statistical model was used for prediction of the consistency coefficient as a function of temperature and concentration which showed a good agreement (r2=0.99) between experimental and theoretical values. The magnitude of activation energy were found to be in the range of 8.6 to 14.08 kJ/mol.K.

scholarly journals Rheological properties and flow behaviour of wax-stabilized water-in-oil emulsions

2021 ◽  
Author(s):  
Samira Haj-Shafiei
Keyword(s):  
Rheological Properties ◽  
Initial Temperature ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Paraffin Wax ◽  
Oscillatory Rheology ◽  
Initial Deposition ◽  
Oil Emulsions ◽  
Light Mineral ◽  
Glycerol Monooleate

The objective of this study was to characterize the flow and rheological behaviour of model wax-stabilized water-in-oil (W/O) emulsions consisting of light mineral oil, paraffin wax and glycerol monooleate as the oil phase and water as the dispersed aqueous phase. An[sic] laboratory-scale benchtop flowloop system was used to explore the flow behaviour of the emulsions' oil phase (oil, paraffin wax and surfactant). The key contribution from this work was that the higher initial temperature gradient (40°C compared to 19°C) experienced by the rapidly-cooled oil led to more initial deposition on the flowloop inner wall. The rheological properties of W/O emulsions with different water cuts (10-50wt%) were also studied. Rotational, oscillatory rheology and creep compliance and recovery were characterized on emulsions aged up to 28 days. Overall, the results demonstrated that emulsion composition, and age could significantly influence an emulsion's flow behaviour and rheological properties.

scholarly journals Rheological properties and flow behaviour of wax-stabilized water-in-oil emulsions

2021 ◽  
Author(s):  
Samira Haj-Shafiei
Keyword(s):  
Rheological Properties ◽  
Initial Temperature ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Paraffin Wax ◽  
Oscillatory Rheology ◽  
Initial Deposition ◽  
Oil Emulsions ◽  
Light Mineral ◽  
Glycerol Monooleate

The objective of this study was to characterize the flow and rheological behaviour of model wax-stabilized water-in-oil (W/O) emulsions consisting of light mineral oil, paraffin wax and glycerol monooleate as the oil phase and water as the dispersed aqueous phase. An[sic] laboratory-scale benchtop flowloop system was used to explore the flow behaviour of the emulsions' oil phase (oil, paraffin wax and surfactant). The key contribution from this work was that the higher initial temperature gradient (40°C compared to 19°C) experienced by the rapidly-cooled oil led to more initial deposition on the flowloop inner wall. The rheological properties of W/O emulsions with different water cuts (10-50wt%) were also studied. Rotational, oscillatory rheology and creep compliance and recovery were characterized on emulsions aged up to 28 days. Overall, the results demonstrated that emulsion composition, and age could significantly influence an emulsion's flow behaviour and rheological properties.

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