CFD and Experimental Studies of Yield Power-Law Fluids in Turbulent Pipe Flow

2018 ◽  
Author(s):  
Abdalsalam Ihmoudah ◽  
M. A. Rahman ◽  
Stephen D. Butt
Keyword(s):  
Turbulent Flow ◽  
Power Law ◽  
Pressure Loss ◽  
Xanthan Gum ◽  
Newtonian Fluids ◽  
Turbulent Pipe Flow ◽  
Flow Loop ◽  
Horizontal Pipe ◽  
Cfd Models ◽  
Power Law Fluids

The transport of Non-Newtonian fluids through pipelines and mud circulation in wellbores often occur in turbulent flow regimes. In this study, experiments and computational fluid dynamics (CFD) models are used to examine the influence of yield power law (YPL) fluid rheological properties on pressure loss in the flow loop in turbulent flow. Three Non-Newtonian fluids at different concentrations of Xanthan gum solutions (0.05%, 0.10% and 0.15%, by weight) are studied at flow rates ranging between 400 and 800 L/min. A fully instrumented flow loop system was used, consisting of three main sections of different inclinations: 5 m long horizontal, 5 m vertical, and 3 m inclined 45° test section. Additionally, CFD codes of ANSYS CFX 17.2 are examined and compared to experimental results. These models are based on the Reynolds Averaged Navier-Stokes (RANS) equations. The comparison is done with the results of these investigations, based on vertical and horizontal pipe frictional pressure drops. The results show that the gap between experimental and CFD models has been increased in comparison with increase concentration Xanthan gum solution at the same density of fluids. Specifically, pressure loss rises with rises in the consistency index, k and flow behaviour index, However, rises in yield stress τ0 showed less impacts on frictional pressure losses. Given these simulation outcomes, it is clear that pressure drop in the Non-Newtonian fluid in one phase flow can be more accurately predicted by used the Reynolds-Stress Models (RSM) more than Eddy-viscosity models.

Modeling Turbulent Flow of Non-Newtonian Fluids Using Generalized Newtonian Models

2015 ◽  
Author(s):  
Majid Bizhani ◽  
Ergun Kuru
Keyword(s):  
Turbulent Flow ◽  
Turbulence Model ◽  
Power Law ◽  
Pressure Loss ◽  
Fluid Dynamic ◽  
Turbulence Models ◽  
Velocity Profiles ◽  
Newtonian Fluids ◽  
Generalized Newtonian Fluid ◽  
Power Law Fluids

Computational Fluid Dynamic (CFD) is used to model turbulent flow of non-Newtonian polymeric fluids in concentric annulus. The so called Generalized Newtonian Fluid (GNF) approach is used. Four turbulence models are tested. Applicability of each model in predicting turbulent flow of non-Newtonian fluids in annulus is assessed by comparing results of pressure loss and or velocity profiles with experimental data. The first tested model is a modified version of Lam-Bremhorst k–ε turbulence model. The modification was originally developed to model flow of power law fluids in smooth circular pipes. Results of simulation study showed that this model significantly overestimates the pressure losses. Two k–ε closure type turbulence models, one developed to model turbulent flow of Herschel-Buckley and the other for power law fluids, are shown to fail in predicting turbulent flow of polymer solutions. One of the models contains a damping function which is analyzed to show its inadequacy in damping the eddy viscosity. The last tested model is a one layer turbulence model developed for predicting turbulent flow in annular passages. The model has an adjustable parameter, which is shown to control the slope of velocity profiles in the logarithmic region. It is demonstrated that if the model constant is selected carefully, the model accurately predicts pressure loss and velocity profiles.

Turbulent Flow of Power-Law Fluids Through Circular Pipes

AIAA Journal ◽  
2002 ◽  
Vol 40 (1) ◽  
pp. 181-185
Author(s):  
Z. U. A. Warsi
Keyword(s):  
Turbulent Flow ◽  
Power Law ◽  
Circular Pipes ◽  
Power Law Fluids

Modeling of Newtonian Fluids in Annular Geometries With Inner Pipe Rotation

2010 ◽  
Author(s):  
Mehmet Sorgun ◽  
Jerome J. Schubert ◽  
Ismail Aydin ◽  
M. Evren Ozbayoglu
Keyword(s):  
Axial Velocity ◽  
Pressure Loss ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Newtonian Fluids ◽  
Flow Loop ◽  
Eccentric Annulus ◽  
Pressure Losses ◽  
Proposed Model ◽  
Pipe Rotation

Flow in annular geometries, i.e., flow through the gap between two cylindrical pipes, occurs in many different engineering professions, such as petroleum engineering, chemical engineering, mechanical engineering, food engineering, etc. Analysis of the flow characteristics through annular geometries is more challenging when compared with circular pipes, not only due to the uneven stress distribution on the walls but also due to secondary flows and tangential velocity components, especially when the inner pipe is rotated. In this paper, a mathematical model for predicting flow characteristics of Newtonian fluids in concentric horizontal annulus with drill pipe rotation is proposed. A numerical solution including pipe rotation is developed for calculating frictional pressure loss in concentric annuli for laminar and turbulent regimes. Navier-Stokes equations for turbulent conditions are numerically solved using the finite differences technique to obtain velocity profiles and frictional pressure losses. To verify the proposed model, estimated frictional pressure losses are compared with experimental data which were available in the literature and gathered at Middle East Technical University, Petroleum & Natural Gas Engineering Flow Loop (METU-PETE Flow Loop) as well as Computational Fluid Dynamics (CFD) software. The proposed model predicts frictional pressure losses with an error less than ± 10% in most cases, more accurately than the CFD software models depending on the flow conditions. Also, pipe rotation effects on frictional pressure loss and tangential velocity is investigated using CFD simulations for concentric and fully eccentric annulus. It has been observed that pipe rotation has no noticeable effects on frictional pressure loss for concentric annuli, but it significantly increases frictional pressure losses in an eccentric annulus, especially at low flow rates. For concentric annulus, pipe rotation improves the tangential velocity component, which does not depend on axial velocity. It is also noticed that, as the pipe rotation and axial velocity are increased, tangential velocity drastically increases for an eccentric annulus. The proposed model and the critical analysis conducted on velocity components and stress distributions make it possible to understand the concept of hydro transport and hole cleaning in field applications.

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.

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

Numerical Study on Gas-Yield Power-Law Fluid in T-Junction Minichannel

2019 ◽  
Author(s):  
Abdalsalam Ihmoudah ◽  
Mohamed M. Awad ◽  
Aziz Rahman ◽  
Stephen D. Butt
Keyword(s):  
Film Thickness ◽  
Power Law ◽  
Xanthan Gum ◽  
Numerical Study ◽  
Superficial Velocity ◽  
Bubble Velocity ◽  
Two Phase ◽  
Ansys Fluent ◽  
Power Law Fluids ◽  
Taylor Bubbles

Abstract In this study, a computational examination of Taylor bubbles was performed for gas/non-Newtonian fluid two-phase flows developed in a minichannel T-junction mixer with a hydraulic diameter of 1 mm. The investigations employed three separate aqueous xanthan gum solutions at concentrations of 0.05, 0.1 and 0.15 w/w, which are referred to as non-Newtonian (yield power-law) fluids. The effective concentration of the xanthan gum solutions and superficial velocity of the inlet liquid phase on the length, velocity, and shape of the Taylor bubbles was studied using the ANSYS FLUENT 19 software package. The simulation results show an increase in bubble velocity with increasing film thickness, particularly in solutions of higher viscosity XG-0.15%. Furthermore, bubble lengths decreased as the xanthan gum concentrations increased, but bubble shapes underwent alterations when the concentrations increased. Another interesting result of the tests shows that when the liquid inlet velocity increases, bubble lengths decrease during lower liquid superficial velocity, whereas during higher velocities, they change only slightly after increases in concentration. Finally, with increasing XG concentration, the liquid film thickness around the bubble increased. The results show good agreement with correlations after modifying a capillary number (Ca*) for non-Newtonian liquids in all cases.

Effect of Polymer Fluid Viscoelastic Properties on the Initiation of Transition From Laminar to Turbulent Flow Regime and the Drag Reduction in the Flow Through Horizontal Pipe

2020 ◽  
Author(s):  
Mehmet Meric Hirpa ◽  
Ergun Kuru
Keyword(s):  
Turbulent Flow ◽  
Drag Reduction ◽  
Flow Regime ◽  
Shear Viscosity ◽  
Viscoelastic Properties ◽  
Dynamic Pressure ◽  
Flow Loop ◽  
Horizontal Pipe ◽  
Fluid Elasticity ◽  
Turbulent Flow Regime

Abstract This study investigated the flow of viscoelastic fluids through horizontal pipeline mainly focusing on the effect of fluid elasticity on drag reduction and onset of transition to turbulent flow regime. In order to be able to see the sole effect of fluid elasticity (independent from shear viscosity), three non-Newtonian fluids having the same shear viscosity but different viscoelastic properties were tested in the horizontal flow loop. Those fluids were the dilute solutions of partially hydrolysed polyacrylamide (HPAM) and they were prepared by using three polymer grades of HPAM (i.e. 5 × 105, 8 × 106, 20 × 106 g/gmol) in different compositions. Experiments have shown that increasing fluid elasticity resulted in higher drag reduction in pipe flow. Moreover, fluid elasticity affected the onset of turbulent flow and an earlier transition to turbulent flow regime (as compared to water flow) was only observed for the flow of fluid having the highest elastic properties. So, understanding effects of fluid elasticity on flow dynamics might improve the performance of fluids engineered for hole cleaning/cuttings transport in oil and gas well drilling or proppant transport in hydraulic fracturing operations. Also, field efforts to find solutions to problems caused by excessive dynamic pressure losses encountered in drilling horizontal or extended reach wells or in transporting hydrocarbons through pipeline might benefit from the findings of this or further extended research on this subject.

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