scholarly journals Thermal radiation and magnetohydrodynamics flow over a black isothermal plate

2021 ◽  
pp. 246-246
Author(s):  
Andreas Raptis

We study the effects of the thermal radiation and an induced magnetic field on the flow over a black isothermal plate for an optically thin gray fluid. The flowing medium absorbs and emit radiation, but scattering is not included. Numerical solutions are obtained for different values of radiation parameter, Prandtl number, Grashof number and magnetic Prandtl number.

2013 ◽  
Vol 18 (2) ◽  
pp. 599-608
Author(s):  
R. Muthucumaraswamy ◽  
V. Visalakshi

Thermal radiation effects on an unsteady free convective flow of a viscous incompressible flow of a past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion in the presence magnetic field are considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature is raised to Tw and the concentration level near the plate is also raised to Cʹw . An exact solution to the dimensionless governing equations is obtained by the Laplace transform method, when the plate is exponentially accelerated with a velocity u= u0 exp(aʹtʹ) in its own plane against gravitational field. The effects of velocity, temperature and concentration fields are studied for different physical parameters such as the magnetic field parameter, thermal radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing magnetic field parameter or radiation parameter. But the trend is just reversed with respect to a or t .


2014 ◽  
Vol 44 (1) ◽  
pp. 9-17
Author(s):  
S. AHMED ◽  
A. BATIN

An approximate solution to the problem of steady free convective MHD flow of an incompressible viscous electrically-conducting fluid over an infinite vertical isothermal porous plate with mass convection is presented here. A uniform magnetic field is assumed to be applied transversely to the direction of the flow, taking into account the induced magnetic field with viscous and magnetic dissipations of energy. The dimensionless governing equations are solved by using the series solution method. The induced magnetic field, current density, temperature gradient and flow velocity are studied for magnetohydrodynamic body force, magnetic Prandtl number, Schmidt number and Eckert number. It is observed that the induced magnetic field is found to increase with a rise in magnetic Prandtl number. Current density is strongly reduced with increasing magnetic Prandtl number, but enhanced with Schmidt number. The acquired knowledge in our study can be used by designers to control MHD flow as suitable for a certain applications such as laminar magneto-aerodynamics, and MHD propulsion thermo-fluid dynamics.


2011 ◽  
Vol 7 (2) ◽  
pp. 61-72 ◽  
Author(s):  
Sahin Ahmed

The objective of this investigation is to study the influence of thermal radiation and magnetic Prandtl number on the steady MHD heat and mass transfer by mixed convection flow of a viscous, incompressible, electrically-conducting, Newtonian fluid which is an optically thin gray gas over a vertical porous plate taking into account the induced magnetic field. The similarity solutions of the transformed dimensionless governing equations are obtained by series solution. It is found that, velocity is reduced considerably with a rise in conduction-radiation parameter (R) or Hartmann number (M) whereas the skin friction is found to be markedly boosted with an increase in M or Magnetic Prandtl number (Pm). An increase in magnetic body parameter (M) or Magnetic Prandtl number (Pm) is found to escalate induced magnetic field whereas an increase in R is shown to exert the opposite effect. Applications of the study include laminar magneto-aerodynamics, materials processing and MHD propulsion thermo-fluid dynamics.DOI: 10.3329/jname.v7i2.5662


2017 ◽  
Vol 22 (3) ◽  
pp. 567-582 ◽  
Author(s):  
B.K. Jha ◽  
B. Aina

AbstractThe present work presents a theoretical investigation of an MHD mixed convection flow in a vertical microchannel formed by two electrically non-conducting infinite vertical parallel plates. The influence of an induced magnetic field arising due to motion of an electrically conducting fluid is taken into consideration. The governing equations of the motion are a set of simultaneous ordinary differential equations and their exact solutions in dimensionless form have been obtained for the velocity field, the induced magnetic field and the temperature field. The expressions for the induced current density and skin friction have also been obtained. The effects of various non-dimensional parameters such as rarefaction, fluid wall interaction, the Hartmann number and the magnetic Prandtl number on the velocity, the induced magnetic field, the temperature, the induced current density, and skin friction have been presented in a graphical form. It is found that the effect of the Hartmann number and magnetic Prandtl number on the induced current density is found to have a decreasing nature at the central region of the microchannel.


2017 ◽  
Vol 9 (2) ◽  
pp. 349-361 ◽  
Author(s):  
Muhammad Ashraf ◽  
Iram Iqbal ◽  
M. Masud ◽  
Nazara Sultana

AbstractIn present work, we investigate numerical simulation of steady natural convection flow in the presence of weak magnetic Prandtl number and strong magnetic field by involving algebraic decay in mainstream velocity. Before passing to the numerical simulation, we formulate the set of boundary layer equations with the inclusion of the effects of algebraic decay velocity, aligned magnetic field and buoyant body force in the momentum equation. Later, finite difference method with primitive variable formulation is employed in the physical domain to compute the numerical solutions of the flow field. Graphical results for the velocity, temperature and transverse component of magnetic field as well as surface friction, rate of heat transfer and current density are presented and discussed. It is pertinent to mention that the simulation is performed for different values of algebraic decay parameter α, Prandtl number Pr, magnetic Prandtl number Pm and magnetic force parameter S.


2016 ◽  
Vol 20 (5) ◽  
pp. 1585-1596 ◽  
Author(s):  
Jamalabadia Abdollahzadeh ◽  
Hyun Park ◽  
Chang Lee

This study presents the effect of thermal radiation on the steady flow in a vertical micro channel filled with highly absorbing medium. The governing equations (mass, momentum and energy equation with Rosseland approximation and slip boundary condition) are solved analytically. The effects of thermal radiation parameter, the temperature parameter, Reynolds number, Grashof number, velocity slip length, and temperature jump on the velocity and temperature profiles, Nusselt number, and skin friction coefficient are investigated. Results show that the skin friction and the Nusselt number are increased with increase in Grashof number, velocity slip, and pressure gradient while temperature jump and Reynolds number have an adverse effect on them. Furthermore, a criterion for the flow unsteadiness based on the temperature parameter, thermal radiation parameter, and the temperature jump is presented.


2021 ◽  
Vol 26 (1) ◽  
pp. 122-134
Author(s):  
P. Pramod Kumar ◽  
Bala Siddulu Malga ◽  
Lakshmi Appidi ◽  
Sweta Matta

AbstractThe principal objective of the present paper is to know the reaction of thermal radiation and the effects of magnetic fields on a viscous dissipative free convection fluid flow past an inclined infinite plate in the presence of an induced magnetic field. The Galerkin finite element technique is applied to solve the nonlinear coupled partial differential equations and effects of thermal radiation and other physical and flow parameters on velocity, induced magnetic field, along with temperature profiles are explained through graphs. It is noticed that as the thermal radiation increases velocity and temperature profiles decrease and the induced magnetic field profiles increases.


2021 ◽  
Vol 10 (4) ◽  
pp. 478-490
Author(s):  
M. Venkateswarlu ◽  
P. Bhaskar

The work of steady hydromagnetic stream of Casson liquid in a micro-channel constructed by two indefinite vertical proportionate walls in the appearance of thermal radiation is presented in this article. The effect of an imposed magnetic domain appearing scheduled to movement of an electrically administrating liquid is adopted into account. The exact solutions of the liquid velocity, imposed magnetic domain, and temperature domain have been obtained. Also, the analytical expressions for the skin-friction coefficient and imposed current density are obtained. The basic aspiration of this article is to reinvestigate the supremacy of pertinent physical constraints like magnetic Prandtl number, injection/suction parameter, Hartmann number, thermal radiation parameter, rarefaction parameter, wall ambient temperature difference ratio, and liquid wall interaction parameter over the imposed magnetic field and velocity of the liquid. Lorentz force which is obtained from magnetic field has a propensity to decline the motion of liquid and imposed magnetic field. The imposed current density rises with an enhancement in the hydromagnetic Prandtl number. This study is applied in the machines like transformers, generators, and motors work on the principle of electromagnetic induction. Results are compared with the literature in the limiting case.


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