Rheological Characteristics Of Fluid Research Articles

Comparative study of the accuracy of friction factor correlations developed for flow of inelastic yield power-law fluids in pipes

An extensive review of the friction factor correlations used for pressure loss prediction of yield power-law (YPL) fluid flow in pipes has been conducted, and the results are summarized in this paper.A comparative study was also conducted to determine the predictive performances of various laminar and turbulent friction factor models developed for YPL fluid flow in pipes. Model predictions of frictional pressure losses were validated by comparing them with the experimentally measured pressure drop data obtained from the flow of several YPL fluids in pipes.Investigations were further extended to determine the impact of the variation of YPL fluid rheological characteristics (resulting from using different rheological characterization methods) on the pressure drop predictions.A wide range of generalized Reynolds numbers (i.e., 20 to 9000, as defined by the API-RP:13D) in a pipe flow configuration was considered in the analyses. The yield stress of the test fluids (determined by using the nonlinear curve fitting technique recommended by the API RP:13D) varied from 0.10 to 0.95 Pa.The results indicated that Hanks and Ricks' model predicted the pressure drop of YPL fluid flow in pipes better than any other models, both in laminar and turbulent flow regimes, matching the experimental data within a ±10% error range.Variations of the YPL model parameters (resulting from using different rheological characterization methods) significantly impacted the pressure drop predictions. Using YPL model parameters obtained from the non-iterative dual power law (DPL) approximation method (as recommended by API-RP:13D) and Hanks and Ricks' model yielded the most accurate pressure drop predictions for the pipe flow of YPL fluids.

Impact of physico‐chemical properties of nanocellulose on rheology of aqueous suspensions and its utility in multiple fields: A review

AbstractNanocellulose (NC), due to its sustainable nature, high aspect ratio, superior mechanical strength, and availability of functionalizable OH groups, has been widely utilized as reinforcement in numerous fluids/plastics. The physico‐chemical properties of NC, like surface characteristics, dimensions/aspect ratio and their concentration, significantly impact the interparticle interactions, such as the extent of hydrogen bonding, van derWaalforces, hydrophobicity, electrostatic attraction/repulsion, and cellulose entanglement, and have been found to play a critical role in regulating the overall rheological characteristics of fluids. The functionalized NC aqueous suspension exhibited unique shear thinning properties, thixotropic behavior, and quick steady‐state viscosity recovery and viscoelastic properties. However, upon adding functionalized NC to other fluids, a different impact was noticed. For instance, it improved the viscosity, G′ and mechanical stability of bio‐ink; the setting time and mechanical strength of cementitious fluids; increased the filtration performance and provided a unique thermo‐thickening impact in case of water‐based drilling‐fluid; enhanced viscosity with time and heat in case of oil recovery, and so forth. Keeping in view the notable dependence of the rheology of fluids on NC additives, in the present review article, the impact of various physico‐chemical properties of NC additives on the rheological behavior of NC aqueous suspension and its utility as a rheology modifier in multiple advanced fields has been explored. This review article, compared to previous studies, warrants an update on the impact of recent NC surface functionalization/blending techniques employed and NC aspect ratio on specific properties of multiple advanced fluids.

CFD-PBM simulation of hydrodynamics of microbubble column with shear-thinning fluid

Abstract A numerical simulation was performed to study the hydrodynamics of micro-bubble swarm in bubble column with polyacrylamide (PAM) aqueous solution by using computational fluid dynamics coupled with population balance models (CFD-PBM). By considering rheological characteristics of fluid, this approach was able to accurately predict the features of bubble swarm, and validated by comparing with the experimental results. The gas holdup, turbulent kinetic energy and liquid velocity of bubble column have been elucidated by considering the influences of superficial gas velocity and gas distributor size respectively. The results show that with the rise of the superficial gas velocity, the gas holdup and its peak width increase significantly. Especially, the curve peak corresponding to high gas velocity tends to drift obviously toward the right side. Except for the occurrence of a smooth holdup peak at the column center under the condition of the moderate distributor size, the gas holdups for the small and large distributor sizes become flat in the radial direction respectively. The distribution of turbulent kinetic energy presents an increasingly asymmetrical feature in the radial direction and also its variation amplitude enhances obviously with the rise of gas velocity. The increase in gas distributor size can enhance markedly turbulent kinetic energy as well as its overall influenced width. At the low and moderate superficial gas velocity, the curves of the liquid velocity in radial direction present the Gaussian distributions, whereas the perfect distribution always is broken in the symmetry for high gas velocity. Both liquid velocities around the bubble column center and the ones near both column walls go up consistently with the gas distributor size, especially near the walls at the large distributor size condition.

Experimental study on thermal, rheological and filtration control characteristics of drilling fluids: effect of nanoadditives

Cooling the drill bit is one of the major functions of drilling fluids, especially in high temperature deep drilling operations. Designing stable drilling fluids with proper thermal properties is a great challenge. Identifying appropriate additives for the drilling fluid can mitigate drill-bit erosion or deformation caused by induced thermal stress. The unique advantages of nanoparticles may enhance thermal characteristics of drilling fluids. The impacts of nanoparticles on the specific heat capacity, thermal conductivity, rheological, and filtration control characteristics of water‐based drilling fluids were experimentally investigated and compared in this study. Al2O3, CuO, and Cu nanoparticles were used to prepare the water-based drilling nanofluid samples with various concentrations, using the two-step method. Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) were utilized to study the nanoparticle samples. The nanofluids stability and particle size distribution were, furthermore, examined using Dynamic Light Scattering (DLS). The experimental results indicated that thermal and rheological characteristics are enhanced in the presence of nanoparticles. The best enhancement in drilling fluid heat capacity and thermal conductivity was obtained as 15.6% and 12%, respectively by adding 0.9 wt% Cu nanoparticles. Furthermore, significant improvement was observed in the rheological characteristics such as the apparent and plastic viscosities, yield point, and gel strength of the drilling nanofluids compared to the base drilling fluid. Addition of nanoparticles resulted in reduced fluid loss and formation damage. The permeability of filter cakes decreased with increasing the nanoparticles concentration, but no significant effect in filter cake thickness was observed. The results reveal that the application of nanoparticles may reduce drill-bit replacement costs by improving the thermal and drilling fluid rheological characteristics and decrease the formation damage due to mud filtrate invasion.

Are the rheological properties of water-based and synthetic drilling fluids obtained by the Fann 35A viscometer reliable?

Abstract Drilling fluids are complex materials that display elastoviscoplastic and thixotropic characteristics. Rotational viscometers that impose discrete rotational velocities, such as the Fann 35A, are traditionally employed to evaluate the rheological properties of drilling fluids in field operations due to their robustness and low cost. These viscometers are used to measure the steady-state shear stresses by imposing different shear rates and the transient stress overshoot as an estimation of the fluid's gel strength. In the current work, two synthetic drilling fluids and two bentonite suspensions were tested in a Fann 35A viscometer and in a rotational rheometer to check how accurate the Fann 35A viscometer results can be in comparison to rheometer data. Although the steady-state shear stresses measured by the Fann 35A were corroborated by the corresponding values obtained from the rheometer, the accuracy of Fann 35A on measuring the stress overshoots depends on the fluid rheological characteristics. Two hypotheses were proposed to explain the difference on the stress overshoots: (i) wall slip and (ii) the inappropriate control of the shear rate.

Comparison investigation of fluid rheological characteristics effect on stator temperature field for large hydro-generator based on experiment

Purpose – The purpose of this paper is to explore the relationship of fluid flow and heat transfer inside the generator, a large hydro-generator is taken for an example and the temperature field in the generator is calculated according to computation of fluid field by using of corresponding mathematics methods based on fluid mechanical theory and heat transfer theory. Design/methodology/approach – To calculate the temperature field of the generator more accurately, a large-scale hydro-generator is taken as an example and the mathematical model and physical model of 3D stator temperature field and fluid field are established. And the calculation results of the fluid field are applied into the physics field of generator, coupled relationship between fluid field and temperature field was calculated by using of finite volume method and finite element method, respectively. The temperature fields based on fluid fields and the effect of different fluid flow state on generator temperature were analyzed and compared. Findings – The calculated results shows show good agreement with the measured results, meanwhile the effect of different fluid field state on the temperature field is analyzed and the relationship between temperature fields and fluid fields is achieved, which will provide a theoretical basis for ventilation structure design and calculation of synthesis physical fields. Originality/value – The relationship between temperature fields and fluid fields is obtained, providing a theoretical basis for ventilation structure design and calculation of synthesis physical fields.

Micro Foam Drilling Fluid System Performance Research and Application

Micro foam drilling fluid has irreplaceable advantages in reservoir protection, drilling speed, improve the cementing quality and leak plugging, especially suitable for the "three low" Daqing peripheral oilfield Haita area. Indoor the foaming agent, foam stabilizing agent were screened, Preferably choose the efficient composite foaming agent, stabilizer and thickener, the drilling fluid system is transformed into micro foam drilling fluid system. And evaluate the inhibition, anti temperature, anti pollution (anti clay, calcium, anti kerosene) reservoir protection capability, The micro foam drilling fluid leakage, oil reservoir protection, speed up mechanism and micro foam drilling fluid rheological characteristics were studied, Set up a specific rheological model of Micro Foam Drilling fluid, According to the characteristics of Gulong oilfield,R&D the calculation software of Micro Foam drilling fluid density changes with the temperature, pressure and provide guidance for safe drilling. Field application shows that the system has the advantages of simple preparation,convenient maintenance, easy transformation, drilling fluid properties can meet the requirements of drilling technology, To ensure the safe, fast, and high quality drilling of oil and gas,reduce pollution,improve the productivity of a single well.

Numerical Study on Interaction Between Two Bubbles Rising Side by Side in CMC Solution

A numerical simulation was performed to investigate the interaction of two bubbles rising side by side in shear-thinning fluid using volume of fluid (VOF) method coupled with continuous surface force (CSF) method. By considering rheological characteristics of fluid, this approach was able to accurately capture the deformation of bubble interface, and validated by comparing with the experimental results. The rising of bubble pairs with different configurations, including horizontal alignment and oblique alignment, was simulated by the method. The influences of the bubble initial distance and the bubble alignment were studied by analyzing the bubble deformation, rising paths and flow fields surrounding bubbles. The results indicate that within certain initial bubble spacing of S*3.3 (S*SI/D, SI initial distance between bubbles, and D bubble diameter), the dynamic interaction between two bubbles aligned horizontally shows repulsive effect that decreases with the increase of initial bubble spacing, but weakens to certain degree by the shear-thinning properties of fluid. However, the interaction between two bubbles aligned obliquely presents a repulsive effect for the small angle involved but an attractive impact for the large one, which is yet strengthened by the rheological characteristics of fluid.

Fractal analysis of Herschel-Bulkley fluid flow in a capillary

A fractal model for Herschel-Bulkley fluid in a capillary is proposed based on the fractal theory. The proposed model relates flow rate, velocity, starting pressure gradient and effective permeability to the rheological characteristics of fluid and the structural parameters of capillary, and all parameters in the proposed expressions have clear physical meanings. The analytical expressions reveal the physical principle for Herschel-Bulkley fluid flow in a capillary.

Cold model study of metal droplet descent through fluids including a treatment of the non-Newtonian behaviour as exhibited by molten slag system

In the context of several high temperature metallurgical processes including blast furnaces, a cold model study simulating a metal droplet descent through the surrounding fluid system is presented. The study comprises an experimental programme employing wide range of fluids exhibiting both Newtonian and non-Newtonian behaviour. Such fluid systems are encountered in slag–metal droplet systems where viscosity of the slag system has a significant effect on the kinetics of refining reactions. Slag systems generally possess random network structures comprising internal regions of weak ordering and the presence of these regions may result in non-Newtonian behaviour of the slag. As the viscosity of the slag is very sensitive to structure, a treatment of non-Newtonian behaviour as exhibited by some molten slag systems is therefore required. Two parameters have been identified and estimated that help to determine the rheological characteristics of fluids in relation to their network structure. The underlying principle of the model development has been that the external pressure exerts a driving force that affects the motion of the fluid to a degree dependent on the rheological behaviour and the network structure of the fluid. The paper also describes some results of a cold model study of the momentum transfer to the fluid system by correlating the drag Reynolds number with the modified drag coefficient for non-Newtonian fluids(N*Rem)½−n′ = (NRem)½−n′ (1/2CDm)½

Effects of fracture fluid degradation on underground fracture dimensions and production increase

A detailed computer study has been conducted to determine the effects of fracture fluid rheological characteristics upon fracture growth, proppant transport and placement and ultimate gas recovery. Several examples presented in this paper illustrate that an effective fracture fluid quality control needs to be implemented in order to achieve the desired fracture dimensions and production performance as computed during design procedure. Several actual cases show how the fracture fluid can degrade in quality due to variations in fluid additive concentrations, inefficient mixing procedures, and many other factors. This fluid degradation can lead to inadequate fracture dimensions, poor proppant transport, and loss in ultimate well recovery. The quality of fracture fluid can be effectively maintained by continuously measuring fluid characteristics in the field and controlling its viscous properties by modifying fluid additives, injection rate, etc., during the actual execution of a stimulation treatment. A three-dimensional hydraulic fracture model has been used to compute fracture and proppant characteristics for a wide range of field measured fluid properties in order to illustrate the impact of fracture fluid upon fracture dimensions and proppant transport. Using data computed by the fracturing model, a single-phase analytical model has then been used to predict gas production and ultimate recovery.

The Rheological Characteristics of Electrorheological Fluids in Dynamic Squeeze

This paper is concerned with an experimental and theoretical determination of the rheological performance of an electrorheological (ER) fluid when subjected to time-dependent applied loads. The experimental facility was built as a squeeze cell in which the fluid is sandwiched between two electrodes, one fixed and the other moving, which permits the instantaneous measurement of the mechanical and electrical responses of the fluid. The transient rheological characteristics of the fluid were assessed for various mechanical force levels and for constant voltage excitation of the fluid. Input and output stress levels across the fluid were monitored enabling the dynamic response of the fluid to be determined using a combination of displacement, force, velocity and acceleration transducers. The experimental results were compared with the results from a modified theoretical analysis, which employs a bi-viscous shear stress/shear strain characteristic of the electrically stressed fluid together with a fluid yield stress, which has a strain-direction dependence on the electric field.

Turbulent Pressure Loss of Yield-fluids In Pipes

Abstract A friction factor equation for yield fluids (yield-pseudoplastic, yield-dilatant, Bingham) was derived from flow equation under turbulent pipe flow conditions. The rheological characteristics of the yield fluid were described by Herschel and Bulkley model. To verify the validity of the proposed approach a comparison was made between published experimental friction factors and those calculated from the developed equation and Torrance correlation. Results show that the average absolute relative error between the experimental data and calculated data ranges from 2.84 to 5.05% for the developed equation and from 6.97 to 13.68% for Torrance correlation. A comparison was also made between the field measurements of the pressure loss in Mobil pipeline and those based on the proposed friction factor, the results showed good agreement. The evaluation emphasizes the accuracy of the developed equation in comparison to earlier work. Introduction All over the world, there are several pipelines transporting yield-fluids under turbulent flow conditions. Design of such pipelines requires an adequate relationship to determine the pressure loss. The yield-fluids include yield-pseudoplastic, yield-dilatant and Bingham fluids. The rheological characteristics of these fluids can be described by Herschel and Bulkley(1) model. Equation 1 (available in full paper) where: n > 1.0 for yield-pseudoplastic fluids n < 1.0 for yield-dilatant fluids n = 1.0 for Bingham fluids In view of the correlations developed for predicting the friction factor in a pipeline handling a yield fluid, there are two groups: Bingham correlations and yield-pseudoplastic and yield-dilatant correlations. For Bingham fluids, Workers(2–5) had applied the Prandtl mixing length concept to the turbulent flow in smooth tubes to derive a friction factor formula. Hanks and Dadia(6) extended the analysis of Hanks(7) for the turbulent flow of Newtonian fluids to the case of Bingham plastics. Thomas(8) presented Bingham fluid data on the turbulent pipe flow and correlated his data with Blasius equation. For yield-pseudoplastic and yield-dilatant fluids, there exists only one correlation developed by Torrance(9). He extended Clapp's treatment to the power law yield-pseudoplastic fluids and deduced the following correlation. Equation 2 (available in full paper) A comparison between the friction factor calculated from the above equation and the published experimental data(5, 7, 10–14) show that, Equation (2) can be used to predict the friction factor with average absolute relative error ranging from 6.97 to 13.68%. Therefore, it is necessary to develop a more accurate equation for pipeline design calculations. In the present analysis, an equation relating the friction factor to Reynolds number and yield-fluid characteristics is developed. The validity of the equation is confirmed with published experimental data. Theoretical Analysis The flow equation of an incompressible fluid under steady state, isothermal and fully developed conditions is given by(15). Equation 3–18 (available in full paper) Equation (17) represents the velocity distribution at the turbulent core. The maximum velocity (Umax) is obtained by equating the velocities at the interface between the turbulent core and the laminar sublayer, that is Equation 19–23 (available in full paper) Friction Factor To obtain an equation for friction factor, the following definitions are used, Equation 24–28 (availabl