scholarly journals Thermophoresis and suction/injection roles on free convective MHD flow of Ag–kerosene oil nanofluid

2020 ◽  
Vol 7 (3) ◽  
pp. 386-396
Author(s):  
Himanshu Upreti ◽  
Alok Kumar Pandey ◽  
Manoj Kumar
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Mass Transfer Rate ◽  
Brownian Diffusion ◽  
Particle Volume ◽  
Ohmic Dissipation ◽  
Surface Mass

Abstract In this article, the mass and heat transfer flow of Ag–kerosene oil nanofluid over a cone under the effects of suction/injection, magnetic field, thermophoresis, Brownian diffusion, and Ohmic-viscous dissipation was examined. On applying the suitable transformation, PDEs directing the flow of nanofluid were molded to dimensionless ODEs. The solution of the reduced boundary value problem was accomplished by applying Runge–Kutta–Fehlberg method via shooting scheme and the upshots were sketched and interpreted. The values of shear stress and coefficients of heat and mass transfer were attained for some selected values of governing factors. The obtained results showed that when the amount of surface mass flux shifts from injection to the suction domain, the heat and mass transfer rate grew uniformly. However, they have regularly condensed with the rise in the magnitude of the magnetic field and particle volume fraction. Several researches have been done using cone-shaped geometry under the influence of various factors affecting the fluid flow, yet, there exists no such investigation that incorporated the response of viscous-Ohmic dissipation, heat absorption/generation, suction/blowing, Brownian diffusion, and thermophoresis on the hydro-magnetic flow of silver-kerosene oil nanofluid over a cone.

scholarly journals Magnetorheological Fluids Behaviour in Oscillatory Compression Squeeze: Experimental Testing and Analysis

2019 ◽  
Vol 13 (4) ◽  
pp. 221-225
Author(s):  
Wojciech Horak ◽  
Marcin Szczęch ◽  
Bogdan Sapiński
Keyword(s):  
Magnetic Field ◽  
Volume Fraction ◽  
Experimental Testing ◽  
Magnetic Field Gradient ◽  
Particle Volume Fraction ◽  
Excitation Frequency ◽  
Magnetorheological Fluid ◽  
Density Level ◽  
Particle Volume ◽  
The Magnetic Field

Abstract This article deals with experimental testing of magnetorheological fluid (MRF) behaviour in the oscillatory squeeze mode. The authors investigate and analyse the influence of excitation frequency and magnetic field density level on axial force in MRFs that differ in particle volume fraction. The results show that, under certain conditions, the phenomenon of self-sealing can occur as a result of the magnetic field gradient and a vacuum in the working gap of the system.

The motion of Brownian particles and sediment on an inclined plate

1997 ◽  
Vol 337 ◽  
pp. 25-47 ◽  
Author(s):  
A. A. DAHLKILD
Keyword(s):  
Volume Fraction ◽  
Particle Density ◽  
Particle Volume Fraction ◽  
Present Theory ◽  
Brownian Diffusion ◽  
Inclined Plate ◽  
Particle Volume ◽  
Hindered Settling ◽  
Brownian Particles ◽  
And Migration

The gravitational settling of a homogeneous suspension of Brownian particles on an inclined plate is considered. The hindered settling towards the wall and the viscous, buoyancy-driven bulk motion of the sediment are considered assuming steady conditions and accounting for the effects of Brownian diffusion, shear-induced diffusion and migration of particles due to a gradient in shear stress. Generally, the results show the development of a sediment boundary layer where the settling towards the wall is balanced by Brownian diffusion at the beginning of the plate and by shear-induced diffusion further downstream. Compared to previous results in the literature, the present theory allows steady-state solutions for extended values of the plate inclination and particle volume fraction above the sediment; upon reconsidering the case with non-Brownian particles, a new similarity solution, with a stable shock in particle density, is developed.

scholarly journals Effects of the Hydro Anisotropy and the Magnetic Field on the Dynamic Thermo-Bi-Diffusive Flow in a Horizontal Cavity Confining a Porous Medium Saturated by a Binary Fluid

2021 ◽  
pp. 1-13
Author(s):  
Faras Issiako ◽  
Christian Akowanou ◽  
Macaire Agbomahena
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Porous Medium ◽  
Heat And Mass Transfer ◽  
Transverse Magnetic Field ◽  
Mass Transfer Rate ◽  
Transverse Magnetic ◽  
Binary Fluid ◽  
Diffusive Flow ◽  
Horizontal Cavity

We analyze analytically the effects of anisotropy in permeability and that of a transverse magnetic field on thermal convection in a porous medium saturated with a binary fluid and confined in a horizontal cavity. The porous medium, of great extension, is subjected to various conditions at the thermal and solutal boundaries. The axes of the permeability tensor are oriented obliquely with respect to the gravitational field. Based on a scale analysis, the velocity, temperature, and heat and mass transfer rate fields were determined. These results were validated by the study of borderline cases which are: pure porous media and pure fluid media discussed in the literature. It emerges from this study that the anisotropy parameters influence the convective flow. The application of a transverse magnetic field significantly reduces the speed of the flow and thereby affects the temperature field and the rate of heat and mass transfer.

scholarly journals Magnetic Field Effect on the Double Diffusive Natural Convection in Three-Dimensional Cavity Filled with Micropolar Nanofluid

2018 ◽  
Vol 8 (12) ◽  
pp. 2342 ◽  
Author(s):  
Awatef Abidi ◽  
Zehba Raizah ◽  
Jamel Madiouli
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Transfer Rates ◽  
Micropolar Nanofluid ◽  
Nanoparticles Volume Fraction ◽  
Mass Transfers

This article presents a three-dimensional numerical investigation of heat and mass transfers and fluid flow in a cavity filled with an Al2O3/water micropolar fluid under uniform magnetic field. To solve the governing non-dimensional equations, Finite Volume Method (FVM) based on 3-D vorticity-vector potential formulation has been employed. The effects of various parameters such as buoyancy ratio (−2 ≤ N ≤ 0), Rayleigh number (103 ≤ Ra ≤ 105), Hartmann number (0≤ Ha≤ 60), nanoparticles volume fraction (0 ≤ φ ≤ 0.06) and micropolar material parameter (0≤ K≤ 5) on flow structure and on heat and mass transfers are presented. The results illustrate that for the micropolar nanofluid model, both heat and mass transfer rates and three-dimensional character of the flow are smaller when compared with the pure nanofluid model. It is also observed that increase and decrease in heat and mass transfer rates is experienced due to increase in Rayleigh number and Hartmann number, respectively. It is also noted that increase in vortex viscosity parameter reduces the average heat and mass transfer rates and is more evident when the magnetic field is imposed. Combined effects of magnetic field and nanoparticles volume fraction on heat and mass transfers are also explored.

Double Diffusive Convection in Flow Couple Stress Nanofluid in a Permeable Wall Vertical Channel in the Presence of a Magnetic Field

2019 ◽  
Vol 26 ◽  
pp. 30-44
Author(s):  
Noureddine Messaoudi ◽  
Mohamed Nadjib Bouaziz ◽  
Hamza Ali Agha
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Brownian Motion ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Couple Stress ◽  
Volume Fraction ◽  
Nonlinear Partial Differential Equations ◽  
Vertical Channel ◽  
Strong Impact

In this work, the flow of a couple stress nanofluid in a vertical channel with heat and mass transfer in the presence of a magnetic field and taking account the Brownian motion, the thermophoresis as well as the effect of Soret and Dufour was simulated numerically using Matlab following the code bvp4c. The nonlinear partial differential equations governing this particular flow are transformed into a system of ordinary differential equations via the similarity technique. The influence of the parameters describing the behavior of the problem studied on the velocity, temperature, concentration and volume fraction fields of the nanoparticles, as well as on the coefficient of friction, Nusselt and Sherwood numbers, were highlighted for the end of the study. understand their effect on heat and mass transfer. The rheology of the nanofluid and the magnetic field have a strong impact on the velocity and temperature profiles, while the parameters of Brownian motion and thermophoresis promote heat transfer.

Heat and mass transfer in non-coaxial rotation of radiative MHD Casson carbon nanofluid flow past a porous medium

2021 ◽  
Vol 2 (2) ◽  
pp. 37-51
Author(s):  
W.N.N. Noranuar ◽  
A.Q. Mohamad ◽  
S. Shafie ◽  
I. Khan ◽  
L.Y. Jiann
Keyword(s):  
Magnetic Field ◽  
Carbon Nanotubes ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Moving Boundary ◽  
Volume Fraction ◽  
Transform Method ◽  
Casson Nanofluid ◽  
Multi Wall Carbon Nanotubes ◽  
The Laplace Transform

The heat and mass transfer of a radiative Casson nanofluid with single-wall and multi-wall carbon nanotubes in a non-coaxial rotating frame is analyzed in this article. The effects of thermal radiation, magnetic field and porosity are considered. Casson human blood is used to suspend both types of carbon nanotubes. The governed dimensional momentum, energy and concentration equations associated with initial and moving boundary conditions are converted into dimensionless expression by applying appropriate dimensionless variables. The exact solutions are determined by solving the dimensionless governing partial differential equations using the Laplace transform method. The obtained solutions are verified by comparing the present results with the published results. The validity of the solutions is assured since a precise agreement between the results is accomplished. The variation of the skin friction, Nusselt number, and Sherwood number for various values of the embedded parameters are presented in tables. The impacts of embedded parameters on the velocity, temperature and concentration profiles are illustrated in graphs. The distribution of the velocity and temperature is enhanced by the nanoparticles volume fraction but a reverse effect is observed for concentration profile. The radiation parameter has amplified the velocity and temperature of the Casson nanofluid. The emergence of porosity effect has aided to the smoothness of fluid flow but the presence of magnetic field reports the opposite effect on the velocity.

scholarly journals Experimental and numerical study on surface roughness of magnetorheological elastomer for controllable friction

Friction ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 917-929 ◽  
Author(s):  
Rui Li ◽  
Xi Li ◽  
Yuanyuan Li ◽  
Ping-an Yang ◽  
Jiushan Liu
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Surface Morphology ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Rubber Matrix ◽  
Magnetorheological Elastomer ◽  
Particle Volume ◽  
Simulation Results ◽  
The Magnetic Field

Abstract Magnetorheological elastomer (MRE) is a type of smart material of which mechanical and electrical properties can be reversibly controlled by the magnetic field. In this study, the influence of the magnetic field on the surface roughness of MRE was studied by the microscopic modeling method, and the influence of controllable characteristics of the MRE surface on its friction properties was analyzed by the macroscopic experimental method. First, on the basis of existing studies, an improved mesoscopic model based on magnetomechanical coupling analysis was proposed. The initial surface morphology of MRE was characterized by the W-M fractal function, and the change process of the surface microstructures of MRE, induced by the magnetic interaction between particles, was studied. Then, after analyzing the simulation results, it is found that with the increase in the magnetic field and decrease in the modulus of rubber matrix, the surface of MRE changes more significantly, and the best particle volume fraction is within 7.5%–9%. Furthermore, through experimental observation, it is found that the height of the convex peak on the surface of MRE decreases significantly with the action of the magnetic field, resulting in a reduction in the surface roughness. Consistent with the simulation results, a particle volume fraction of 10% corresponds to a maximum change of 14%. Finally, the macroscopic friction experiment results show that the friction coefficients of MREs with different particle volume fractions all decrease with the decrease in surface roughness under the magnetic field. When the particle volume fraction is 10%, the friction coefficient can decrease by 24.7% under a magnetic field of 400 mT, which is consistent with the trend of surface roughness changes. This shows that the change in surface morphology with the effect of the magnetic field is an important factor in the control of MRE friction properties by magnetic field.

Pre-Yield Shearing Regimes of Magnetorheological Fluids

2012 ◽  
Author(s):  
Waad Nassar ◽  
Xavier Boutillon ◽  
José Lozada
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Shear Strain ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Initial Response ◽  
Magnetic Pole ◽  
Particle Volume ◽  
Average Shear ◽  
The Magnetic Field

We analyzed experimentally the pre-yield regime of some MRFs. The hearing response is ruled by two successive regimes and limited by an interfacial phenomenon. The initial response is pseudo-elastic and independent from the magnetic field and of the particle volume fraction. The shear-stress limit of this regime is proportional to the square of the magnetic field and to the particle volume fraction. In the next regime, the shear strain is not uniform in the fluid. The increase in average shear stress varies linearly with the increase in average shear strain. The variation coefficient is proportional to the square of the magnetic field and decreases with the particle volume fraction. Finally, a loss of adhesion of the magnetic aggregates with the shearing plate or the magnetic pole occurs. The corresponding shear stress is proportional to the square of the magnetic field and to the particle volume fraction.

scholarly journals Dusty Nanofluid Past a Centrifugally Stretching Surface

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Wubshet Ibrahim ◽  
Dachasa Gamachu
Keyword(s):  
Magnetic Field ◽  
Differential Equations ◽  
Velocity Profile ◽  
Ordinary Differential Equations ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Stretching Surface ◽  
Particle Volume ◽  
Magnetic Field Parameter ◽  
The Magnetic Field

This communication reports, the flow of Cu-water dusty nanofluid past a centrifugally stretching surface under the effect of second order slip and convective boundary conditions. The coupled nonlinear ordinary differential equations are get hold of from the partial differential equations which are derived from the conservation of momentum and energy of both nanofluid and dusty phases. Then, using apt resemblance transformation these ordinary differential equations were altered into a dimensionless form and then solved by bvp5c solver in Matlab software. The variation in velocity and temperature profiles of fluid and dusty phases for different parameters are thrash out in depth by figures and tables. The outcomes exhibit that the velocity profile of both fluid and dusty phases boot as the values of the dust particle volume fraction parameter is enlarged. Besides, the magnetic field parameter has similar effect on the velocity profile of both fluid and dusty phases. Also, the results illustrated that temperature profile of both Cu-water nanofluid and dusty particle phases are improved within an enhancement in the values of the temperature relaxation parameter, Cu-particle volume fraction, and Biot number. The results also confirm that for greater values of the magnetic field parameter the values of skin friction coefficient are enlarged for all values of the velocity ratio parameter.

Radiation and non-uniform heat sink/source effects on 2D MHD flow of CNTs-H2O nanofluid over a flat porous plate

2019 ◽  
Vol 16 (4) ◽  
pp. 791-809
Author(s):  
Himanshu Upreti ◽  
Sawan Kumar Rawat ◽  
Manoj Kumar
Keyword(s):  
Magnetic Field ◽  
Heat Sink ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Porous Plate ◽  
Mhd Flow ◽  
Particle Volume ◽  
Content Type ◽  
Uniform Heat ◽  
The Impact

Purpose The purpose of this paper is to examine the velocity and temperature profile for a two-dimensional flow of single- and multi-walled nanotubes (CNTs)/H2O nanofluid over a flat porous plate, under the impact of non-uniform heat sink/source and radiation. The influence of suction/blowing, viscous dissipation and magnetic field is also incorporated. Design/methodology/approach The solution of the PDEs describing the flow of nanofluid is accomplished using Runge–Kutta–Fehlberg approach with shooting scheme. Findings Quantities of physical importance such as local Nusselt number and skin friction coefficient for both types of nanotubes are computed and shown in tables. Also, the impact of copious factors like Prandtl number, magnetic field, Eckert number, porosity parameter, radiation parameter, non-linear stretching parameter, injection/suction, heating variable, particle volume fraction and non-uniform heat sink/source parameter on temperature and velocity profile is explained in detail with the aid of graphs. Originality/value Till date, no study has been reported that examines the role of radiation and non-uniform heat sink/source on MHD flow of CNTs‒water nanofluid over a porous plate. The numerical outcomes attained for the existing work are original and their originality is authenticated by comparing them with earlier published work. This problem is of importance, as there are many applications of the fluid flowing over a flat porous plate.

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