scholarly journals Determination of Rheological Parameters from Measurements on a Viscometer with Coaxial Cylinders

10.14311/832 ◽  
2006 ◽  
Vol 46 (3) ◽  
Author(s):  
F. Rieger
Keyword(s):  
Power Law ◽  
Rheological Model ◽  
Newtonian Fluids ◽  
Rheological Parameters ◽  
Model Parameters ◽  
Coaxial Cylinders ◽  
Power Law Fluids

The paper deals with measurements of non-Newtonian fluids on a viscometer with coaxial cylinders. The procedure for determining the rheological model parameters is recommended  for power-law fluids and Bingham plastics. 

Friction Coefficients for Bingham and Power-Law Fluids in Abrupt Contractions and Expansions

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Sergio L. D. Kfuri ◽  
Edson J. Soares ◽  
Roney L. Thompson ◽  
Renato N. Siqueira
Keyword(s):  
Reynolds Number ◽  
Yield Stress ◽  
Power Law ◽  
Reynolds Numbers ◽  
Newtonian Fluids ◽  
Rheological Parameters ◽  
Friction Coefficients ◽  
K Value ◽  
Power Law Fluids ◽  
Pipeline Systems

Industrial processes with non-Newtonian fluids are common in many segments such as petroleum, cosmetic, and food industries. Slurries, emulsions, and gas–liquid dispersions are some examples with industrial relevance. When a fluid flows in a pipe system, pressure losses are always present. For Newtonian fluids, a quite reasonable understanding of this phenomenon was already achieved and is available in the literature. The same cannot be stated for non-Newtonian fluids owing to their complex characteristics, such as pseudoplasticity, viscoplasticity, elasticity, and thixotropy. The understanding of the influence of these characteristics on flow behavior is very important in order to design efficient pipeline systems. The design of such systems requires the estimation of the pressure drop due to friction effects. However, there are few works regarding friction losses for non-Newtonian fluids in pipeline systems, making this task a difficult one. In this study, two classes of fluids are investigated and compared with the Newtonian results. The first category of fluids are the ones that exhibits pseudoplastic behavior and can be modeled as a power-law fluid, and the second category are the ones that possesses a yield stress and can be modeled as a Bingham fluid. Polyflow was used to compute the friction losses in both abrupt contractions and expansions laminar flow conditions. It shows that for the expansion cases, the aspect ratio affects more the local friction coefficients than for the contraction cases. The influence of the power index n on local friction losses is similar for both cases, abrupt contractions and abrupt expansions. At low Reynolds numbers, dilatant fluids present the lowest values of the friction coefficient, K, independent of geometry. At high Reynolds numbers, a reversal of the curves occurs, and the dilatant fluid presents larger values of K coefficient. For the cases investigated, there is also a Reynolds number in which all the curves exhibit the same value of K for any value of the power-law index. The effect of τy′ shows a different behavior between contractions and expansions. In the case of contractions, the material with the highest dimensionless yield stress has the highest K value. In the case of the expansions, the behavior is the opposite, i.e., the higher the yield stress, the lower is the values of the K coefficient. Equations for each accessory as a function of the rheological parameters of the fluid and the Reynolds number of the flow are also proposed. The data were adjusted according to two main equations: the two Ks method proposed by Hooper (1981, “The Two-K Method Predicts Head Losses in Pipe Fittings,” Chem. Eng., 81, pp. 96–100.) is used for all the contractions cases, and the equation proposed by Oliveira et al. (1997, “A General Correlation for the Local Coefficient in Newtonian Axisymmetric Sudden Expansions,” Int. J. Heat Fluid Flow, 19(6), pp. 655–660.) is used for all the expansions cases. The equations found were compared with the numerical results and showed satisfactory precision and thus can be used for engineering applications.

scholarly journals Determination of Rheological Parameters from Measurements on a Viscometer with Coaxial Cylinders – Choice of the Reference Radius

10.14311/892 ◽  
2006 ◽  
Vol 46 (6) ◽  
Author(s):  
F. Rieger
Keyword(s):  
Experimental Data ◽  
Power Law ◽  
Rheological Behavior ◽  
Experimental Results ◽  
Rheological Parameters ◽  
Concentrated Suspensions ◽  
Rotational Viscometer ◽  
Coaxial Cylinders

Knowledge about rheological behavior is necessary in engineering calculations for equipment used for processing concentrated suspensions and polymers. Power-law and Bingham models are often used for evaluating the experimental data. This paper proposes the reference radius to which experimental results obtained by measurements on a rotational viscometer with coaxial cylinders should be related. 

Experimental verification of power-law non-Newtonian axisymmetric porous gravity currents

2013 ◽  
Vol 731 ◽  
Author(s):  
Sandro Longo ◽  
Vittorio Di Federico ◽  
Luca Chiapponi ◽  
Renata Archetti
Keyword(s):  
Power Law ◽  
Gravity Currents ◽  
Nonlinear Ordinary Differential Equation ◽  
Rheological Parameters ◽  
Homogeneous Porous Media ◽  
Power Law Fluids ◽  
Water Glycerol ◽  
Similar Solutions ◽  
Selection Of

AbstractWe present a theoretical and experimental analysis of axisymmetric gravity currents of power-law fluids in homogeneous porous media. The non-Newtonian shear-thinning fluid is a mixture of water, glycerol and Xanthan gum ($n= 0. 33{\unicode{x2013}} 0. 53$), and it is injected into a porous layer of glass beads ($d= 1{\unicode{x2013}} 3~\mathrm{mm} $). We compare experiments conducted with constant ($\alpha = 1$) and time-increasing ($\alpha = 1. 5$ and $2. 0$) influxes to theoretical self-similar solutions obtained by the numerical integration of the nonlinear ordinary differential equation that describes one-dimensional transient motion. The theoretical analysis is confirmed by experimental data. In addition, the selection of the most appropriate expression for the tortuosity factor and the choice of the correct range of shear stress for the determination of the rheological parameters are shown to be crucial to obtaining a good fit between the theory and experiments.

Determination of Hagenbach and Coutte Correction Factors for the Flow of Power Law Fluids

1998 ◽  
Vol 35 (4) ◽  
pp. 237-242 ◽  
Author(s):  
N. V. K. Dutt
Keyword(s):  
Power Law ◽  
Correction Factors ◽  
Power Law Fluids

Electrochemical determination of diffusivities in non-newtonian power-law fluids by a rotating geiss body

1987 ◽  
Vol 35 (3) ◽  
pp. 191-199 ◽  
Author(s):  
I. Nikov ◽  
V. Beschkov ◽  
P. Stoyanova
Keyword(s):  
Power Law ◽  
Electrochemical Determination ◽  
Power Law Fluids

On the mass transfer in non-newtonian fluids I. Transfer from spheres to power law fluids

1980 ◽  
Vol 7 (1) ◽  
pp. 43-53 ◽  
Author(s):  
S. Kumar ◽  
P.K. Tripathi ◽  
S.N. Upadhyay
Keyword(s):  
Mass Transfer ◽  
Power Law ◽  
Newtonian Fluids ◽  
Power Law Fluids

Flow of Non-Newtonian Power-Law Fluids Through Porous Media

1979 ◽  
Vol 19 (03) ◽  
pp. 155-163 ◽  
Author(s):  
A.S. Odeh ◽  
H.T. Yang
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Porous Media ◽  
Test Data ◽  
Power Law ◽  
Newtonian Fluids ◽  
Unsteady State ◽  
Partial Differential ◽  
State Flow ◽  
Power Law Fluids

Abstract The partial differential equation that describes the flow, of non-Newtonian, power-law, slightly compressible fluids in porous media is derived. An approximate solution, in closed form, is developed for the unsteady-state flow behavior and verified by. two different methods. Using the unsteady-state solution, a method for analyzing injection test data is formulated and used to analyze four injection tests. Theoretical results were used to derive steady-state equations of flow, equivalent transient drainage radius, and a method for analyzing isochronal test data. The theoretical fundamentals of the flow, of non-Newtonian power-law fluids in porous media are established. Introduction Non-Newtonian power-law fluids are those that obey the relation = constant. Here, is the viscosity, e is the shear rate at which the viscosity is measured, and n is a constant. Examples of such fluids are polymers. This paper establishes the theoretical foundation of the flow of such fluids in porous media. The partial differential equation describing this flow is derived and solved for unsteady-state flow. In addition, a method for interpreting isochronal tests and an equation for calculating the equivalent transient drainage radius are presented. The unsteady-state flow solution provides a method for interpreting flow tests (such as injection tests).Non-Newtonian power-law fluids are injected into the porous media for mobility control, necessitating a basic porous media for mobility control, necessitating a basic understanding of the flow behavior of such fluids in porous media. Several authors have studied the porous media. Several authors have studied the rheological properties of these fluids using linear flow experiments and standard viscometers. Van Poollen and Jargon presented a theoretical study of these fluids. They described the flow by the partial differential equation used for Newtonian fluids and accounted for the effect of shear rate on viscosity by varying the viscosity as a function of space. They solved the equation numerically using finite difference. The numerical results showed that the pressure behavior vs time differed from that for Newtonian fluids. However, no methods for analyzing flow-test data (such as injection tests) were offered. This probably was because of the lack of analytic solution normally required to understand the relationship among the variables.Recently, injectivity tests were conducted using a polysaccharide polymer (biopolymer). The data showed polysaccharide polymer (biopolymer). The data showed anomalies when analyzed using methods derived for Newtonian fluids. Some of these anomalies appeared to be fractures. However, when the methods of analysis developed here were applied, the anomalies disappeared. Field data for four injectivity tests are reported and used to illustrate our analysis methods. Theoretical Consideration General Consideration The partial differential equation describing the flow of a non-Newtonian, slightly compressible power-law fluid in porous media derived in Appendix A is ..........(1) where the symbols are defined in the nomenclature. JPT P. 155

Capillary Filling Dynamics of Electromagnetohydrodynamic Flow of Non-Newtonian Fluids

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Jeffy John Philip ◽  
Joydeb Mukherjee ◽  
Sandip Sarkar ◽  
Sandip K. Saha
Keyword(s):  
Power Law ◽  
Transverse Magnetic ◽  
Newtonian Fluids ◽  
Force Balance ◽  
Rheological Parameters ◽  
Scaling Analysis ◽  
Total Force ◽  
Capillary Filling ◽  
Stress Parameter ◽  
Comparison Results

Abstract In this work, we aim to develop a mathematical model for capillary filling dynamics of electromagnetohydrodynamic flow of non-Newtonian fluids. An axially applied electric field and a transverse magnetic field are considered to elucidate the electromagnetohydrodynamic transport through the microcapillary. Assuming a non-Newtonian power-law obeying fluids, we analyze the transient evolution of the electromagnetohydrodynamic capillary positions by considering the magnitude of the total force balance via finite volume-based numerical formalism. We have highlighted the various rheological regimes in the horizontal capillary through a scaling analysis. For the Newtonian fluids, corresponding inviscid linear Washburn regime is also analyzed and compared with the power-law obeying fluids. Furthermore, we have also derived closed-form analytical expressions for the electromagnetohydrodynamic velocity, pressure gradient, and transient evolution of the capillary positions by using couple stress parameter model to characterize the fluid rheological behaviors. We perform a comparison test of the coupled stress parameter model with the results from the literature for a similar set of fluid rheological parameters. The comparison results are found to be in good agreement.

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