A comparative note on the free convection of micropolar nanofluid due to the interaction of buoyancy and the dissipative heat energy

Heat Transfer ◽  
2021 ◽  
Author(s):  
Pradyumna K. Pattnaik ◽  
Jyotsnarani Pattnaik ◽  
Satya R. Mishra ◽  
Bagh Ali
Keyword(s):  
Free Convection ◽  
Heat Energy ◽  
Dissipative Heat ◽  
Micropolar Nanofluid ◽  
Comparative Note

The impacts of non-uniform magnetic field on free convection heat transfer of a magnetizable micropolar nanofluid

2019 ◽  
Vol 29 (10) ◽  
pp. 3685-3706
Author(s):  
Zafar Namazian ◽  
S.A.M. Mehryan
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Content Type ◽  
Viscosity Parameter ◽  
Micropolar Nanofluid ◽  
Free Convection Heat

Purpose The purpose of this study is to numerically study the heat transfer of free convection of a magnetizable micropolar nanofluid inside a semicircular enclosure. Design/methodology/approach The flow domain is under simultaneous influences of two non-uniform magnetic fields generated by current carrying wires. The directions of the currents are the same. Although the geometry is symmetric, it is physically asymmetric. The impacts of key parameters, including Rayleigh number Ra = 103-106, Hartman number Ha = 0-50, vortex viscosity parameter Δ = 0-4, nanoparticles volume fraction φ = 0-0.04 and magnetic number Mnf = 0-1000, on the macro- and micro-scales flows, temperature and heat transfer rate are studied. Finding The outcomes show that dispersing of the nanoparticles in the host fluid increases the strength of macro- and micro-scale flows. When Mnf = 0, the increment of the vortex viscosity parameter increases the strength of the particles micro-rotations, while this characteristic is decreased by growing Δ for Mnf ≠ 0. The increment of Δ and Ha decreases the rate of heat transfer. The increment of Ha decreases the enhancement percentage of heat transfer rate because of dispersing nanoparticles, known as En parameter. In addition, the value of Δ has no effect on En. Moreover, the average Nusselt number Nuavg and En remain constant by increasing the magnetic number Mnf for different volume fraction values. Originality/value The authors believe that all of the results, both numerical and asymptotic, are original and have not been published elsewhere yet.

scholarly journals Numerical solution of Stokes problem for free convection effects in dissipative dusty medium

2004 ◽  
Vol 2004 (72) ◽  
pp. 3975-3988 ◽  
Author(s):  
V. Venkataraman ◽  
K. Kannan
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Stokes Problem ◽  
Temperature Fields ◽  
Dust Particles ◽  
Two Phase ◽  
Dusty Fluid ◽  
Dissipative Heat ◽  
Phase Fluid

The flow past an infinite vertical isothermal plate started impulsively in its own plane in a viscous incompressible two-phase fluid has been considered by taking into account the viscous dissipative heat. The coupled nonlinear equations governing the flow are solved for fluid and particle phases by finite difference method. The velocity and temperature fields have been shown graphically forGbeing positive for dusty air and it was observed that the same results hold for water. (Gdenotes the Grashof number andG>0corresponds to cooling of the plate by free convection currents.) The results forG<0(heating of the plate) have been verified and discussed. The numerical values of skin friction and the rate of heat transfer of dusty fluid are shown in tables. The effects ofGandE(the Eckert number) on the flow field are discussed. It is observed that dusty fluid causes an increase in skin friction. The increase in mass concentration of dust particles decreases the heat transfer rate. The presence of inert particles does not admit the reverse type of flow even for large values oft.

Free convection effects on the oscillatory flow past an infinite, vertical, porous plate with constant suction. II

1973 ◽  
Vol 333 (1592) ◽  
pp. 37-50 ◽  
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Oscillatory Flow ◽  
Porous Plate ◽  
Transient Temperature ◽  
Dissipative Heat ◽  
Constant Suction ◽  
Two Dimensional Flow ◽  
Transient Velocity

An analysis of a two-dimensional flow of an incompressible, viscous fluid is presented here for the unsteady flow. The mathematical analysis having been presented in part I, only the solutions for the transient velocity profiles, transient temperature profiles, the amplitude and the phase of the skin friction and the rate of heat transfer are presented in this paper. They are shown graphically. The effects of heating or cooling the plate ( G < > 0) the Eckert number ( E ), the Prandtl number ( P ), and the frequency ( ω ) are discussed. It has been observed that a reversed type of flow occurs when the plate is heated by the free convection currents. The amplitude of the skin friction is not affected significantly by the free convection currents when the frequency is large. In the case of air, the phase of the skin friction is more, when the plate is cooled than that when it is heated, by the free convection currents. Also, owing to greater viscous dissipative heat for G > 0, or to greater cooling of the plate, the amplitude of the skin friction increases, whereas owing to greater viscous dissipative heat for G < 0 or to greater heating of the plate, the amplitude of the skin friction decreases. But the amplitude of the rate of heat transfer increases owing to greater heating or cooling of the plate. However, it is more when the plate is cooled than that when the plate is heated.

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