Hydromagnetic Natural Convection Flow Research Articles

Laminar boundary layers in three‐dimensional MHD natural convective flow past a semi‐infinite vertical plate with variable sinusoidal suction

AbstractThe primary goal of this study is to investigate how the diffusion‐thermo and thermo‐diffusion affect a three‐dimensional hydromagnetic natural convective flow of a radiating fluid past a uniformly moving isothermal and isosolutal semi‐infinite vertical plate subjected to a sinusoidal suction velocity. The asymptotic series expansion method is adopted to solve the equations governing the flow model and to find the analytical solutions. The effect of variable suction on the flow and transport characteristics is mainly highlighted in the study. Both the diffusion‐thermo and thermo‐diffusion effects improve the fluid velocity.

Effect of Rayleigh number on transport of solute in a hydromagnetic natural convective flow through a vertical channel with chemical reaction

In the present research, the transport of solute in a hydromagnetic natural convective flow through a vertical channel under the impact of bulk chemical reaction is investigated for the first time using Mei's multi-scale homogenization method. The purpose of this research is to obtain an analytical solution of a physical model for a vertical flow. A uniformly variable axial temperature is considered at both walls. Analytical expressions of Taylor dispersivity, multi-dimensional concentration distributions i.e. horizontal concentration, vertical mean and real concentration distributions are obtained together in the present article. One of the major fact of the present study is to highlight the influence of Rayleigh number (Ra) on mass transfer phenomena in the above mentioned flow. It is observed that both the velocity and Taylor dispersivity reduce due to the increment of the Hartmann and Rayleigh numbers. The Rayleigh number imposes the horizontal uniformity throughout the vertical channel and with the increment of Ra, the variation of horizontal distribution of concentration reduces but it remains tri-modal. It is important to note that, when the Rayleigh number reaches to 275, the non-uniform variation of horizontal concentration distribution becomes bimodal. It is significant to note that a critical value of the Rayleigh number is suggested where the horizontal variation curve becomes bimodal from tri-modal. The outcomes of this study may have a wide range of industrial applications, including metal casting, crystal growth and liquid metal cooling blankets for fusion reactors.

Heatline visualization in hydromagnetic natural convection flow inside a prismatic heat exchanger using nanofluid

Heatline visualization in hydromagnetic natural convection flow inside a prismatic heat exchanger using nanofluid

Chemical reaction on hydromagnetic natural convective flow over an unlimited perpendicular permeable plate

AbstractIn this paper, we have explored the hydromagnetic free convective flow over an unlimited perpendicular porous plate in the presence of temperature resources. The prevailing equations are subsequently solved systematically by utilizing the perturbation methodology. The velocity, temperature as well as concentration sketches are shown in graphical profiles. The impacts in the flow area for dissimilar leading parameters have been explored. Also, the skin frictions, the Nusselt quantity along with the Sherwood quantity are computed with different parameters and mentioned in the tables. The velocity diminishes with an escalation in the chemically reacting parameter as well as improves with an increment in the temperature resource parameter. The temperature field reduces with an augment in the Prandtl number. The concentration field is enhanced by amplifying in the chemically reacting variable, whereas it lessens with amplifying in the Schmidt number.

Interplay of conducting and non-conducting walls on hydromagnetic natural convection flow in a vertical micro-channel with Hall current

Theoretical investigation on the interaction between conducting and non-conducting walls on hydromagnetic natural convection flow of viscous incompressible and electrically conducting fluid through a vertical micro-channel taking into account the effects of induced magnetic field in presence of Hall current is presented. Governing coupled equations responsible for the flow are obtained when either the micro-channel walls are electrically conducting or are electrically non-conducting. Using the method of undetermined coefficients, exact solution are obtained and presented in dimensionless form subject to relevant boundary conditions. Expressions for fluid velocity, induced magnetic field, skin friction, volume flow rate and induced current density in both primary and secondary flow directions are also obtained. Effects of some governing parameters like Hall current parameter, rarefaction parameter and Hartmann number on the different flow situations are given using the aid of line graphs and Tables. The main conclusion of the present analysis is that, in the existence of rarefaction parameter, primary fluid velocity could be enhanced with the increase in Hall parameter when the micro-channel walls are either insulated or when the left micro-channel wall is electrically conducting. Results obtained in this work are relevant in many magnetically controlled devices and could also be used as a benchmark in checking the accuracies of result obtained in some empirical experiments.

Effect of a Point/Line Heat Source on Hydromagnetic Free Convection between Vertical Walls due to Induced Magnetic Field

The hydromagnetic natural convective flow of an incompressible electrically conducting and viscous liquid amid non-conducting vertical walls with a constant point heat source/sink under the impact of the induced magnetic field has been studied. A wavelet function is used to formulate the point heat source. The considered problem is described by a group of simultaneous ODEs with significant boundary conditions, and their solutions have been acquired for the induced magnetic field, the velocity field and the temperature field by applying the Laplace technique. The skin friction, induced current density and mass flux have also been discussed. The influences of controlling parameters on the fluid flow are discussed with the tables and graphs. The valuable consequence of this investigation is that an enhancement in the length of point heat source enhances the induced magnetic field, velocity, induced current density and temperature field.

Influence of Hall current on hydromagnetic natural convective flow between two vertical concentric cylinders in presence of heat source/sink

AbstractThe fully developed laminar magnetohydrodynamic free convection between two concentric vertical cylinders with Hall currents and heat source/sink, in the presence of the radial magnetic field, are studied. The governing thermal energy and momentum equations are changed into ordinary differential equations whose solutions are determined in closed‐form expressions of the Bessel and modified Bessel functions of order zero. A parametric investigation illustrating the impacts of the Hall current, magnetic field, heat source, and radii ratio has been accomplished graphically to examine the changes in temperature as well as velocity while the Nusselt number, mass flux, and skin friction values have been presented in tabular forms. The results ensure that the Hall current has a strong and direct impact on the flow character, such that the influence of the Hall parameter enhances the velocity fields in the appearance of heat source and sink. The velocity remains almost constant as the Hall parameter value is greater than four. Moreover, the velocity and temperature fields have an increasing tendency due to the heat source and inversely for the heat sink.

Influence of Hall current and rotation on the radiative MHD flow past an impulsively started infinite vertical porous plate

The present investigation deals with the effects of hall current, and Soret number on the non linear, radiative, unsteady, hydromagnetic natural convection flow of an optically thick rotating fluid past an impulsively started vertical porous plate. Exact analytical solution of the non-dimensional governing equations is obtained in closed form by using Laplace transform technique. The numerical values of primary and secondary velocity profiles are displayed graphically for different values of pertinent flow parameters.

Effects of Hall Current and Magnetic Field Inclination on Hydromagnetic Natural Convection Flow in a Micro-Channel With Asymmetric Thermal Boundary Condition

AbstractThis study examines the impact of induced magnetic field and Hall current on steady fully developed hydromagnetic natural convection flow in a micro-channel under the action of an inclined magnetic field. The mathematical model responsible for the present physical situation is presented in a dimensionless form under relevant boundary conditions. The governing coupled equations are solved exactly. A parametric study of some physical parameters is conducted and a representative set of numerical results for the velocity field, the induced magnetic field, induced current density, volume flow rate, and skin friction on the micro-channel surfaces are illustrated graphically. It is observed that magnetic field inclination plays an important role in flow formation inside the micro-channel. Numerical computation reveals that the increase in inclination angle reduces the hydromagnetic drag leading to enhancement in primary fluid velocity, while the impact is just converse on the secondary fluid velocity. Furthermore, the increase in Hall current parameter increases the magnitude of the fluid velocity in both primary and secondary flow directions.

Ffects Radiation and Thermal Diffusion on Hydromagnetic Natural Convection Flow of a Rotating and Chemically Reacting Fluid Past an Infinite Vertical Flat Plate in the Presence of Heat Sink

ffects Radiation and Thermal Diffusion on Hydromagnetic Natural Convection Flow of a Rotating and Chemically Reacting Fluid Past an Infinite Vertical Flat Plate in the Presence of Heat Sink

Numerical Simulation of Hydromagnetic Natural Convection Flow in a Grooved Enclosure Filled with CuO–Water Nanofluid Considering Brownian Motion

The influence of magnetic field on natural convection flow and heat transfer in a grooved enclosure filled with nanofluid has been analyzed numerically in the present study. The vertical and grooved walls of the enclosure are kept at constant low temperature while the top horizontal walls are thermally insulated and different thermal boundary conditions are set to the bottom horizontal walls. The fluid within the enclosure is initially assumed to be at rest and the initial temperature of the nanofluid is considered at low temperature. The governing equations representing the flow model are converted into dimensionless form using appropriate transformations and then solved with finite element method based on Galerkin weighted residual technique. The effects of pertinent parameters have been displayed graphically and discussed in terms of streamlines, isotherms, average Nusselt number, average temperature, mean velocity and mid height velocities, respectively. The results indicate that the heat transfer rate in terms of average Nusselt number increases with the increase in Rayleigh number and solid volume fraction of nanoparticales but decreases for increasing strength of magnetic field. Moreover, it is also found that the various thermal boundary conditions have significant effects on the flow and thermal fields inside the enclosure. In addition, the heat transfer rate accelerates significantly in presence of square grooves. Comparisons with previously published results are performed and the results are found to be in excellent agreement.

Analysis of Unsteady Hydromagnetic Natural Convective Dissipative Flow through an Inclined Plate

Analysis of Unsteady Hydromagnetic Natural Convective Dissipative Flow through an Inclined Plate

Unsteady Hydromagnetic Natural Convection Flow Past an Oscillating Vertical Surface with Hall Effect and Convective Boundary Condition

The aim of this paper is to analyze the effect of Hall current on unsteady MHD free convection flow of a viscous, incompressible and electrically conducting fluid past an oscillating vertical plate with convective boundary condition. The fluid flow is due to both the oscillation and the convective heating of the plate. The resulting governing equations are nondimensionalized and solved analytically using the Laplace transform technique. Numerical results for axial and transverse velocities and temperature as well as the skin-friction coefficient and Nusselt number are shown graphically for various values of pertinent flow parameters.

Hydromagnetic natural convection flow of water-based nanofluid along a vertical wavy surface with heat generation

Abstract The interaction of nanoparticles (Al 2 O 3 (alumina) and Ag (silver) ) with external applied magnetic field in the presence of internal heat generation along the vertical rough surface of sinusoidal nature is major concern of this study. The problem is formulated in mathematical form by using the model of Tiwari and Das [19]. The obtained system of partial differential equations is transformed into dimensionless form and then solved numerically by an appropriate finite difference scheme. The values of skin friction coefficient and Nusselt number are obtained for emerging dimensionless parameters and are shown graphically. The important factors for the present study are Al 2 O 3 (alumina) and Ag (silver) nanoparticles, heat generation parameter, wavy amplitude, magnetic parameter, volume fraction parameter of nanoparticle and Prandtl number. To predict the flow and heat transfer along the surface of sinusoidal nature, streamlines and isotherm lines are also plotted.

MHD Natural Convection Flow of Casson Nanofluid over Nonlinearly Stretching Sheet Through Porous Medium with Chemical Reaction and Thermal Radiation.

In the present work, the effects of chemical reaction on hydromagnetic natural convection flow of Casson nanofluid induced due to nonlinearly stretching sheet immersed in a porous medium under the influence of thermal radiation and convective boundary condition are performed numerically. Moreover, the effects of velocity slip at stretching sheet wall are also examined in this study. The highly nonlinear-coupled governing equations are converted to nonlinear ordinary differential equations via similarity transformations. The transformed governing equations are then solved numerically using the Keller box method and graphical results for velocity, temperature, and nanoparticle concentration as well as wall shear stress, heat, and mass transfer rate are achieved through MATLAB software. Numerical results for the wall shear stress and heat transfer rate are presented in tabular form and compared with previously published work. Comparison reveals that the results are in good agreement. Findings of this work demonstrate that Casson fluids are better to control the temperature and nanoparticle concentration as compared to Newtonian fluid when the sheet is stretched in a nonlinear way. Also, the presence of suspended nanoparticles effectively promotes the heat transfer mechanism in the base fluid.

SORET, HALL CURRENT, ROTATION, CHEMICAL REACTION AND THERMAL RADIATION EFFECTS ON UNSTEADY MHD HEAT AND MASS TRANSFER NATURAL CONVECTION FLOW PAST AN ACCELERATED VERTICAL PLATE

The heat and mass transfer characteristics of the unsteady hydromagnetic natural convection flow with Hall current and Soret effect of an incompressible, viscous, electrically conducting, heat absorbing and optically thin radiating fluid flow past a suddenly started vertical infinite plate through fluid saturated porous medium in a rotating environment are taken into account in this paper. Derivations of exact analytical solutions are aimed under different physical properties. The velocity, concentration and temperature profiles, Sherwood number and Nusselt number are easily examined and discussed via the closed forms obtained. Soret effect and permeability parameter tends to accelerate primary and secondary fluid velocities whereas hall current, radiation and heat absorption have reverse effect on it. Radiation and heat absorption have tendency to enhance rate of heat transfer at the plate. The results obtained here may be further used to verify the validity of obtained numerical solutions for more complicated transient free convection fluid flow problems.

Unsteady Hydromagnetic Natural Convection Flow Past a Vertical Plate with Time-Dependent Free Stream through a Porous Medium in the Presence of Hall Current, Rotation, and Heat Absorption

AbstractAn investigation of the unsteady hydromagnetic natural convection flow of a viscous, incompressible, electrically conducting, and heat-absorbing fluid past an infinite vertical plate through a fluid-saturated porous medium with a time-dependent free stream in a rotating system with Hall effects is carried out. An exact solution of the governing equations is obtained using the Laplace transform technique. Two cases of interest are discussed, viz, (1) the impulsive movement of the free stream and (2) the accelerated movement of the free stream. Expressions for the shear stresses at the plate as a result of the primary and secondary flows and the rate of heat transfer at the plate are derived. Asymptotic behavior of the solution is analyzed for both small and large values of time t to highlight the transient approach to the steady-state flow and to gain some physical insight into the flow pattern. A reverse flow exists in the secondary flow direction because of the presence of the thermal buoyancy fo...

Hydromagnetic natural convective heat transfer flow in an isosceles triangular cavity filled with nanofluid using two-component nonhomogeneous model

In this paper, a numerical investigation is presented to study Buongiorno's mathematical model for hydromagnetic free convection flow in an isosceles triangular cavity filled with nanofluid. The inclined walls of the cavity are maintained at constant cold temperature whereas various combinations of the thermal boundary conditions at the bottom heated wall are considered. The cavity is permeated by an inclined uniform magnetic field and the effects of Brownian motion and thermophoresis are incorporated into the nanofluid model. The Galerkin weighted residual finite element method has been employed to solve the governing partial differential equations after converting them into a non-dimensional form using a suitable transformation of variables. In the numerical simulations, alumina-water based nanofluid has been taken into account. Comparisons with previously published work are performed and excellent agreement is obtained. The effects of various parameters such as Hartmann number, Rayleigh number and inclined magnetic field angle on streamlines, isotherms and isoconcentrations have been displayed graphically. The heat transfer augmentation for various combination of model parameters as well as various thermal boundary conditions have been done in light of the average Nusselt number from the bottom heated wall. The results show that the heat transfer rate can be decreased with the increasing values of the Hartmann number and inclination angle of the magnetic field but it can be increased by increasing the Rayleigh number and by reducing the diameter of the nanoparticles. The obtained numerical results also indicate that the variable thermal boundary conditions have significant effects on the flow and thermal fields.

Unsteady/Steady Hydromagnetic Flow of Reactive Viscous Fluid in a Vertical Channel with Thermal Diffusion and Temperature Dependent Properties

The problem of unsteady as well as steady hydromagnetic natural convection and mass transfer flow of viscous reactive, incompressible and electrically conducting fluid between two vertical walls in the presence of uniform magnetic field applied normal to the flow region is studied. Thermal diffusion, temperature dependent variable viscosity and thermal conductivity are assumed to exist within the channel. The governing partial differential equations are solved numerically using implicit finite difference scheme. Results of the computations for velocity, temperature, concentration, skin friction, rate of heat and mass transfer are presented graphically to study the hydrodynamic behavior of fluid in the channel.

Heat and Mass Transfer Effects on Unsteady MHD Natural Convection Flow of a Chemically Reactive and Radiating Fluid through a Porous Medium Past a Moving Vertical Plate with Arbitrary Ramped Temperature

Investigation of unsteady hydromagnetic natural convection flow with heat and mass transfer of a viscous, incompressible, electrically conducting, chemically reactive and optically thin radiating fluid past an exponentially accelerated moving vertical plate with arbitrary ramped temperature embedded in a fluid saturated porous medium is carried out. Exact solutions of momentum, energy and concentration equations are obtained in closed form by Laplace transform technique. The expressions for the shear stress, rate of heat transfer and rate of mass transfer at the plate for both ramped temperature and isothermal plates are derived. The numerical values of fluid velocity, fluid temperature and species concentration are displayed graphically whereas those of shear stress, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. It is found that, for isothermal plate, the fluid temperature approaches steady state when t  1.5 . Consequently, the rate of heat transfer at isothermal plate approaches steady state when t  1.5 .