scholarly journals Unsteady conducting dusty gas flow through a circular pipe in the presence of an applied and induced magnetic field

1993 ◽  
Vol 17 (1) ◽  
pp. 55-64
Author(s):  
Colette Calmelet-Eluhu ◽  
Philip Crooke
Author(s):  
Huei Chu Weng

The presence of current flow in an electric and magnetic field results in electromagnetic force and joule heating. It is desirable to understand the roles of electromagnetic force and joule heating on gas microflow and heat transfer. In this study, a mathematical model is developed of the pressure-driven gas flow through a long isothermally heated horizontal planar microchannel in the presence of an external electric and magnetic field. The solutions for flow and thermal field and characteristics are derived analytically and presented in terms of dimensionless parameters. It is found that an electromagnetic driving force can be produced by a combined non-zero electric field and a negative magnetic field and results in an additional velocity slip and an additional flow drag. Also, a joule heating can be enhanced by an applied positive magnetic field and therefore results in an additional temperature jump and an additional heat transfer.


2011 ◽  
Vol 89 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Kh. S. Mekheimer ◽  
Mohammed H. Haroun ◽  
M. A. El Kot

A mathematical model for blood flow through an elastic artery with overlapping stenosis under the effect of induced magnetic field is presented. The present theoretical model may be considered as a mathematical representation to the movement of conductive physiological fluid through coaxial tubes such that the inner tube is uniform and rigid, representing a catheter tube, while the outer tube is an anisotropically tapered elastic cylindrical tube filled with a viscous incompressible electrically conducting fluid, representing blood. The analysis is carried out for an artery with mild local narrowing in its lumen, forming a stenosis. Analytical expressions for the stream function, the magnetic force function, the axial velocity, the axial induced magnetic field, and the distribution of the current density are obtained. The results for the resistance impedance, the wall shear stress distribution, the axial velocity, the axial induced magnetic field, and distribution of the current density have been computed numerically, and the results were studied for various values of the physical parameters, such as the the Hartmann number Ha, the magnetic Reynolds number Rm, the taper angle ϕ, the maximum height of stenosis δ, the degree of anisotropy of the vessel wall n, and the contributions of the elastic constraints to the total tethering K.


Author(s):  
Nematollah Askari ◽  
Hossein Salmani ◽  
Mohammad Hasan Taheri ◽  
Mojtaba Masoumnezhad ◽  
Mohammad Ali Kazemi

In the present study, the heat transfer of nanofluid magnetohydrodynamic (MHD) fluid flow through a channel with radiation and viscous dissipation effect is considered. Also, the induced magnetic field is considered. The main aim of the study is to obtain the impact of the induced magnetic field, nanoparticle volume fraction, non-electrically conducting, and conducting walls on the MHD nanofluid flow and heat transfer. Hence, the governing equations include momentum, energy, and induced magnetic field equations that are transformed into non-dimensional forms. The analytical least square method (LSM) and numerical finite element method (FEM) effectively conducted for solving the problem. The results of LSM and FEM are compared, and it is observed that there is an excellent agreement. The effect of several parameters such as Hartmann number, suction/injection parameter, magnetic Prandtl number, radiation parameter, Eckert number, and nanoparticle volume fraction are demonstrated and discussed. It can be concluded that the augmentation of the Hartmann number reduces the value of velocity by up to 50%, and the magnetic Prandtl number augmentation reduces the non-dimensional velocity value of about 10% but increases the induced current density value more than twice. Moreover, the increase of radiation parameter, Eckert number, and nanoparticle volume fraction enhance the heat transfer by 20–50%. Besides, the absolute value of the induced magnetic field increases when the Hartmann number rises. Further, the injection parameter decreases the value of velocity and induced magnetic field by 40–50%; whereas, the value of temperature increases by about 40%, and the induced current density increases by 5–7 times. The suction parameter has the contrary effect.


2016 ◽  
Vol 16 (03) ◽  
pp. 1650030 ◽  
Author(s):  
G. C. SHIT ◽  
M. ROY

A nonlinear micropolar fluid model is considered with a view to examine the effect of induced magnetic field on blood flow through a constricted channel. We assume that the flow is unidirectional and flowing through a narrow channel, where the Reynolds number is less than unity such as in microvessels. Under the low Reynolds number approximation, the analytical expressions for axial velocity, micro-rotation component, axial pressure gradient, axial induced magnetic field, resistance to flow and wall shear stress have been obtained. The flow characteristic phenomena have been analyzed by taking valid numerical values of the parameters, which are applicable to blood rheology. The present analytical solutions have been compared with the analytical solutions of Hartmann (Hartmann J. Hg-Dynamics-I: Theory of the laminar flow of an electrically conductive liquid in a homogeneous magnetic field, Mathematisk-Fysiske Meddeleser XV:6, 1937) and found excellent agreement. The study shows that with the increasing values of the magnetic field strength decreases the axial velocity at the central line of the channel, while the flow is accelerating in the vicinity of the channel wall. The induced magnetic field has an increasing effect on the micro-rotation component, which in turn produces increasing pressure gradient. The electrical response of the microcirculation increases with the increase in the Hartmann number and the stenosis height. Thus, the resultant flow predictions presented here may be useful for the potential applications in cardiovascular engineering.


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