Bingham Plastic Fluid Research Articles

Bingham Plastic Fluid Flow between Two Parallel Plates with Temperature Effect

Fluid flow between two parallel plates, both are at rest has been considered in this work. It describes the theoretical analysis of Bingham Plastic fluid model between the plates. The equation of motion, continuity equation and energy equations are solved simultaneously by assuming the plates are of same temperature. A semi analytical solution has been developed and the flow behavior and temperature effect has been discussed and represented with respect to different lubricant parameter.

Forced Convection in a Bingham Plastic Fluid from a Heated Rotating Cylinder

Forced Convection in a Bingham Plastic Fluid from a Heated Rotating Cylinder

Peristaltic Flow of the Bingham Plastic Fluid in a Curved Channel

In this paper, we study the peristaltic transport of incompressible Bingham plastic fluid in a curved channel. The formulation of the problem is presented through, the regular perturbation technique for small values of is used to find the final expression of stream function. The numerical solution of pressure rise per wave length is obtained through numerical integration because its analytical solution is impossible. Also the trapping phenomenon is analyzed. The effect of the variation of the physical parameters of the problem are discussed and illustrated graphically.

Load and stiffness of a hydrostatic bearing lubricated with a Bingham plastic fluid

Using a smart fluid, for example, magnetorheological or electrorheological, in a hydrostatic bearing gives the possibility to actively change the bearing properties during operation. This work presents an analytical model to predict the load and stiffness of a planar hydrostatic bearing lubricated with a Bingham plastic fluid. The model is validated with the use of a numerical model that uses the Bingham–Papanastasiou regularization to achieve convergence. The model gives insight into the size of the operational range of the bearing and the load characteristic.

Combined Effects of Fluid Yield Stress and Geometrical Arrangement on Natural Convection in a Square Duct From Two Differentially Heated Horizontal Cylinders

Abstract Laminar natural convection in Bingham plastic fluids has been investigated from two differentially heated cylinders arranged either one above the other or along the diagonal of the square enclosure. The coupled momentum and energy equations have been solved to elucidate the effect of Rayleigh number (104–106), Prandtl number (10–100), Bingham number (0.01 to Bnmax), and the gap between the two cylinders in terms of the geometric parameters (0 to −0.25 for vertical alignment and 0.15 to 0.35 for diagonal alignment) on the detailed structure of the flow field and the overall heat transfer characteristics of the system. New extensive results are visualized in terms of streamlines, isotherm contours, and variation of the local Nusselt number along various surfaces. Additional insights are developed by examining the shear-rate contours and the yield surfaces delineating the fluid-like and solid-like regions in the flow domain. At high values of the Bingham number, the average Nusselt number reaches its asymptotic value corresponding to the conduction limit. The increasing Rayleigh number promotes fluid-like behavior which promotes heat transfer. The augmentation in heat transfer depends on the volume of fluid participating in the buoyancy-induced flow. For the vertical arrangement, the average Nusselt number (for the heated cylinder) decreases a little as these are moved slightly away from the center of the enclosure, followed by an increase as the two cylinders approach one of the sidewalls; this is so even in the conduction limit. In contrast, when the two cylinders are arranged along the diagonal, the Nusselt number progressively decreases as the gap between the two cylinders increases. Finally, predictive correlations have been developed for the average Nusselt number and the limiting Bingham number thereby enabling their estimation in a new application.

Effect of a rotating cylinder on the flow of a Bingham plastic fluid in T-junction: Momentum and heat transfer characteristics

The present numerical work investigates the momentum and heat transfer characteristics of a Bingham plastic fluid in a rectangular T-channel. A rotating cylinder which is placed in a T-junction mimics the behaviour of a rotating valve to regulate the fluid flow and enthalpy in the two branches of the channel. Numerical simulations are carried out over a wide range of conditions (based on the cylinder diameter): Reynolds number (10-2⩽Re≤40), Bingham number (10-2⩽Bn≤20), Prandtl number (10⩽Pr≤100) and rotational velocity of the cylinder (-5⩽α≤5) where α is the circumferential velocity normalized by the inlet velocity. Extensive results are presented in the form of streamline patterns, isotherm contours and yielded/unyielded regions in the vicinity of the T-junction. In particular, the major thrust of this study is to predict the hydrodynamic forces and torque exerted on the cylinder, flow split ratio (i.e., flow rates in the two outlet branches), critical Bingham number (beyond which no flow separation occurs). Also, the outlet temperatures, enthalpy gain, distribution of Nusselt number over the cylinder surface and its average value as a function of the governing dimensionless parameters have been investigated. The present results show that the rotation of the cylinder can aid or suppress the formation of the recirculation zones effectively which appear on the left wall of the main branch and lower wall of the side branch depending upon the Reynolds number while it always suppresses the cylinder wake. As expected, the Bingham number stabilizes the flow by suppressing the recirculation zone while the Reynolds number tends to promote it. The flow split ratio is found to be significantly affected by the direction of the cylinder rotation. The cylinder rotation also shows a strong impact on the mean values of the hydrodynamic forces and torque. The temperature of the exiting relative streams is seen to be higher for the lower Reynolds and Prandtl numbers, and higher Bingham numbers while cylinder rotation shows a weak effect. The enthalpy gain by the main branch is found to be significantly affected by all the parameters. It has also been observed that the rate of heat transfer is higher for a clockwise rotating cylinder than in the case of an anticlockwise rotating cylinder.

Effect of an inclined magnetic field on peristaltic flow of Bingham plastic fluid in an inclined symmetric channel with slip conditions

This paper studies the influence of an inclined magnetic field on peristaltic transport of incompressible Bingham plastic fluid in an inclined symmetric channel with heat transfer and mass transfer. Slip conditions for heat transfer and concentration are employed. The formulation of the problem is presented through, the regular perturbation technique for small Bingham number Bn is used to find the final expression of streamfunction, the flow rate, heat distribution and concentration distribution. The numerical solution of pressure rise per wave length is obtained through numerical integration because its analytical solution is impossible. Also the trapping phenomenon is analyzed. The effect of the physical parameters of the problem are discussed and illustrated graphically.

Buoyancy-assisted flow of yield stress fluids past a cylinder: Effect of shape and channel confinement

• Fluid yield-stress suppresses flow field in severely confined flows. • Confinement of cylinder can lead to augmentation in heat transfer rate . • Shape of the cylinder significantly affects the momentum and thermal transport in channel confined flow. • Strong aiding buoyancy causes flow reversal at the walls at low Reynolds numbers . The aiding-buoyancy mixed convection heat transfer in Bingham plastic fluids from an isothermal cylinder of elliptical and circular shape in a vertical adiabatic channel is numerically investigated. For a fixed shape of the elliptical cylinder E = 2 (ratio of major to minor axes), the effect of confinement is studied for three values of blockage ratio, B , defined as the ratio of the channel width to the circumference of the cylinder/π, as 6.5, 2.17 and 1.3. In order to delineate the role of cross-section of the cylinder, results are also presented here for a circular cylinder of the same heat transfer area as the elliptical cylinder. The results presented herein span the range of conditions as: Bingham number, 0 ≤ Bn ≤ 100, Reynolds number, 1 ≤ Re ≤ 40, and Prandtl number, 1 ≤ Pr ≤ 100 over the range of Richardson number Ri = 0 (pure forced convection) to Ri = 10. Extensive results on drag coefficient, local and surface averaged values of the Nusselt number and yield surfaces are presented herein to elucidate the combined effects of buoyancy, blockage ratio and fluid yield stress. The morphology of the yield surfaces shows that the unyielded plug regions formed upstream and downstream of the cylinder grow faster at low Reynolds numbers with the increasing yield stress effects under the weak buoyancy forces, i.e., small values of Grashof or Richardson number. The heat transfer enhancement is observed with the increasing channel-confinement due to the sharpening of the temperature gradients near the surface of the cylinder. The average Nusselt number shows a positive dependence on the Reynolds number, Prandtl number and Richardson number irrespective of the shape of the cylinder or the type of fluid. By employing the modified definitions of the dimensionless parameters (based on the two choices of the overall effective fluid velocity), predictive correlations have been established for estimating the value of the average Nusselt number in a new application.

Native and modified porcine plasma protein as wall materials for microencapsulation of natural essential oils

SummaryPorcine plasma protein (PPP) is of interest as a wall material to encapsulate lemongrass oil, turmeric oil and eucalyptus oil using emulsion technique and freeze drying. The properties of microcapsules were used to evaluate two types of wall material (native porcine plasma protein; NPPP and modified porcine plasma protein; MPPP) at two different ratios of wall material (W) and core material (C) (W:C; 4:1 and 3:1). All NPPP and MPPP emulsions showed Bingham plastic fluid flow behaviours. Moreover, MPPP microcapsules showed lower free oil content on their surface (0.10–0.50%) with higher encapsulation efficiency (91–98%). Fourier‐transform infrared spectroscopy showed the outstanding chemical structure of microcapsules. Furthermore, scanning electron microscopy indicated holes on the surface of microcapsules encapsulated with essential oils. Both PPPs can be used as encapsulation material for natural extract and food additives to improve the food texture and as a biopolymer film to maintain the quality of food products.

Free Convection from a Heated Vertical Cone in Generalized Newtonian Fluids

In many situations, heat transfer occurs primarily by free convection, such as that in confined and restricted spaces and/or where it is not possible to induce fluid motion by using a pump or impeller. In this work, natural convection from an isothermal cone in power law and Bingham plastic fluids has been investigated numerically by solving the coupled momentum and energy equations over wide ranges of conditions such as the Grashof number (), the Prandtl number (5–100), the Bingham number (1–50), and the power-law index (0.4–1). The structure of the flow and temperature fields is visualized in terms of streamlines and isotherm contours, yielded and unyielded regions, and the variation of the local Nusselt number along the surface of the cone. The location and shape of the yielded and unyielded regions are influenced by the values of the Grashof and Bingham numbers. The size of the unyielded regions progressively decreases with the increasing Bingham number, whereas the Grashof number promotes the growth of fluidlike regions. Shear-thinning fluid behavior promotes heat transfer with reference to that in Newtonian fluids. On the other hand, the Bingham yield stress has an adverse influence on the overall heat transfer. The present values of the average Nusselt number are correlated in terms of the pertinent dimensionless numbers to enable its prediction in a new application. Finally, a criterion for the onset of convection in Bingham fluid is also reported in terms of ; above which, conduction is the main mode of transport. Thus, the relative magnitudes of the buoyancy and viscous (including the contribution of yield stress) forces determine the degree of deterioration in the rate of heat transfer with reference to that in Newtonian fluids otherwise under identical conditions. This information is valuable: not only in designing heat transfer equipment, but also in the processing of temperature-sensitive materials.

Performance Evaluation of a Magnetorheological Fluid Damper Using Numerical and Theoretical Methods With Experimental Validation

Magnetorheological (MR) fluids which can exhibit substantial reversible rheological changes under the excitation of external magnetic fields, have enabled the construction of many novel and robust electromechanical devices in recent years. Generally, Bingham plastic model is utilised for the estimation of the characteristics of MR fluids. However, when the geometry and design of the MR device as well as the rheological conditions of the fluid itself become complicated due to the engineering application requirements, the accuracy of Bingham plastic model, which simplifies the relation between the fluid shear stress and shear rate into a linear function, is degraded. In this paper, a multi-degree-of-freedom (MDOF) magnetorheological fluid damper with a novel ball-and-socket structure was developed, which was aimed to enhance the human shoulder rehabilitation treatment. The performance of the proposed smart device with its complex design was estimated numerically using a finite element method (FEM) with a Herschel-Bulkley model and theoretically with a model that is based on a Bingham plastic fluid characteristics. The performance of the developed damper was validated experimentally using a dedicated testing facility for various input conditions. It was found that the FEM simulations with the Herschel-Bulkley model showed a better agreement with the experimental results in comparison with the theoretical predictions which were somewhat degraded with the employed Bingham plastic model.

An experimental study on the jet breakup of Bingham plastic slurries in air

The aim of this experimental study is to determine the jet breakup of non-Newtonian, Bingham plastic slurries in air, notably to obtain an experimentally verified formula for the breakup length. The ash-to-water concentration varies between appr. 9% and 57% resulting in Ohnesorge-numbers between 0.0215 and 0.0476. The Bingham plastic fluid discharge from a circular orifice and the jet exit Weber-numbers were varied between 983 and 46866. The Hedström-numbers are between 172 and 235, the Reynolds-numbers were in the range of 906–7169 and the tested Froude-numbers are between 7.06 and 42.13 at standard temperature and ambient pressure. Most of our experiments fall into the second wind-induced regime. A linearly increasing correlation was found for the dimensionless breakup length as a function of We, the Reynolds-, and the Froude-number. The rheology and the particle size distribution of the (fly and bottom) ash were measured and are reported, respectively.

Combined effects of blockage and yield stress on drag and heat transfer from an in-line array of three spheres

This work reports results on the drag and heat transfer from an in-line array of three isothermal spheres falling in a cylindrical confinement filled with Bingham plastic fluids. The effects of dimensionless parameters, such as the Reynolds number (1 ≤ Re ≤ 100), Prandtl number (1 ≤ Pr ≤ 100), Bingham number (0 ≤ Bn ≤ 100), blockage ratio (2 ≤ β ≤ 4) and sphere-to-sphere distance (1.5 ≤ t ≤ 6) have been elucidated. The flow and heat transfer characteristics were analysed in terms of yielded/unyielded regions, streamline and isotherm contours, drag coefficient, pressure coefficient, and local and average Nusselt number. Broadly, the drag coefficient shows a positive dependence on Bn and sphere-to-sphere distance (t) while it exhibits an inverse dependence on Re and β. On the other hand, the Nusselt number shows a positive dependence on Re, Pr, Bn and β; and a complex dependence on t for each sphere. Simple predictive expressions for the average Nusselt number for each sphere are formulated, thereby enabling its prediction in a new application.

Role of slip and heat transfer on peristaltic transport of Herschel-Bulkley fluid through an elastic tube

Purpose This paper is concerned with the peristaltic transport of an incompressible non-Newtonian fluid in a porous elastic tube. The impacts of slip and heat transfer on the Herschel-Bulkley fluid are considered. The impacts of relevant parameters on flow rate and temperature are examined graphically. The examination incorporates Newtonian, Power-law and Bingham plastic fluids. The paper aims to discuss these issues. Design/methodology/approach The administering equations are solved utilizing long wavelength and low Reynolds number approximations, and exact solutions are acquired for velocity, temperature, flux and stream functions. Findings It is seen that the flow rate in a Newtonian fluid is high when contrasted with the Herschel-Bulkley model, and the inlet elastic radius and outlet elastic radius have opposite effects on the flow rate. Originality/value The analysis carried out in this paper is about the peristaltic transport of an incompressible non-Newtonian fluid in a porous elastic tube. The impact of slip and heat transfer on a Herschel-Bulkley fluid is taken into account. The impacts of relevant parameters on the flow rate and temperature are examined graphically. The examination incorporates Newtonian, Power-law and Bingham plastic fluids.

Effect of orientation on the drag of a cone settling in a Bingham plastic fluid

Effects of the orientation and apex angle on the settling velocity of conical particles in Bingham plastic fluids are numerically investigated over a Reynolds number range of 1≤Re≤100, Bingham number range of 0≤Bn≤100, and cone angle range of 20°≤α≤150°. Governing equations (of continuity and momentum) are solved numerically using the finite element method to obtain velocity and pressure fields that are postprocessed to obtain values of the drag coefficient. Furthermore, the effect of cone orientation on the flow field is visualized and explored in terms of streamline contours and the morphology of yielded/unyielded regions. Finally, the obtained values of drag are correlated via a simple predictive expression in terms of the modified Reynolds number. The effect of the cone angle on drag is found to be moderate because the drag force acting on the lateral surface is a small fraction of the overall drag.

Functional and practical analytical pressure surges model through herschel bulkley fluids

Substantially large pressure surges are generated while drilling a well due to tripping operations in which a central drillstring is being moved up or down through non-Newtonian fluid. The presence of these subsurface surge pressures must be considered and determined in almost every well drilled. Wells exhibiting high geothermal temperature gradient further complicate the determination of wellbore pressures since the classical viscometer does not characterize the non-Newtonian nature of fluids accurately at elevated temperatures. More importantly, rheological model selection also plays a key role for effectively proposing safe tripping speeds without violating the mud window constraints. Herschel-Bulkley rheological model has gained more reputation among others due to better predictions of wellbore hydraulic pressures as suggested by the American Petroleum Institute.A new practical and dimensional analytical model was developed for Herschel Bulkley (HB) fluid to calculate pressure surges caused by drillstring movement for non-Newtonian fluids under the fully developed flow (steady state) conditions in the laminar flow range in a slot geometry. The proposed analytical method was applied on unweighted fresh water sepiolite mud as a non-Newtonian fluid since the sepiolite muds are among the few water based muds performing adequately at extreme temperatures as the synthetic and oil base muds. Already measured rheological constants of selected fluid system using both HTHP dynamic rheometer and classical viscometer were considered to obtain surge pressures at ambient to extreme temperature ranges. The results are compared with already developed Burkhardt method for Bingham Plastic fluid and Schuh method for Power Law fluid and other proposed numerical and analytical solutions. Substantial differences on the pressure surges between the conventional viscometer and the HTHP rheometer measurements were also presented. The precision of the developed model is shown to be acceptable for most practical applications. Being operationally easy and applicable with a convenient solution code make the proposed model straightforward to be used as a part of drilling software.

Flow past a rotating sphere in a Bingham plastic fluid, up to a Reynolds number of 10,000

The flow induced by a sphere rotating inside a non-Newtonian, Bingham fluid has been investigated numerically. The rotating sphere is enclosed in a concentric cubic box with solid boundaries. The Bingham number varied between 0.01 and 100,000 and the Reynolds number varied between 0.01 and 10,000. The torque increases with the Bingham number and reaches an asymptotic state at large Bn. The torque is independent of the Reynolds number at high Bn. The yielded region around the sphere has been determined and an empirical equation is found for its extent.

Unsteady Blood Flow with Nanoparticles Through Stenosed Arteries in the Presence of Periodic Body Acceleration

The effects of nanoparticles such as Fe3O4,TiO2, and Cu on blood flow inside a stenosed artery are studied. In this study, blood was modelled as non-Newtonian Bingham plastic fluid subjected to periodic body acceleration and slip velocity. The flow governing equations were solved analytically by using the perturbation method. By using the numerical approaches, the physiological parameters were analyzed, and the blood flow velocity distributions were generated graphically and discussed. From the flow results, the flow speed increases as slip velocity increases and decreases as the values of yield stress increases.

Effect of orientation on forced convection heat transfer from a heated cone in Bingham plastic fluids

Forced convection heat transfer from an isothermal heated cone (apex up and down) in Bingham plastic fluids has been studied numerically. Extensive results are presented here in terms of isotherm and Nusselt number over ranges of conditions as: Reynolds number, 1 ≤ Re ≤ 100, Prandtl number, 10 ≤ Pr ≤ 100, Bingham number, 0 ≤ Bn ≤ 100 and cone angle, 20° ≤ α ≤ 150°. The rate of heat transfer is influenced mainly by the values of Re, Pr and Bn and to a lesser extent by the cone angle and orientation. The present results are consolidated in terms of the modified Reynolds (Re⁎) and Prandtl numbers (Pr⁎) incorporating the role of Bingham number.

On the stability of thermocapillary convection of a Bingham fluid in an infinite liquid layer

The linear stability of thermocapillary liquid layer of a Bingham-plastic fluid is studied. Due to the yield stress of Bingham fluid, there is a plug region in the flow, which divides the yielded flow into two regions. When the flow is subjected to a small perturbation, the velocity perturbation below the upper surface of plug region is negligible, while the temperature perturbation can be found in all flow regions at moderate and small Prandtl numbers (Pr). The perturbation amplitude of the upper surface of plug region decreases rapidly with the increase of Pr. The preferred modes are the upstream oblique wave and the downstream streamwise wave at small and large Pr, respectively. The effects of the yield stress, gravity and the interfacial heat transfer on the flow stability are discussed. The perturbation amplitude only appears above the plug region, which differs from the cases in the plane Bingham–Poiseuille flow and the thermocapillary liquid layer of a Carreau fluid.