Unsteady MHD Mixed Convection Flow of Non-Newtonian Casson Hybrid Nanofluid in the Stagnation Zone of Sphere Spinning Impulsively

In the present analysis, an unsteady MHD mixed convection flow is scrutinized for a non-Newtonian Casson hybrid nanofluid in the stagnation zone of a rotating sphere, resulting from the impulsive motion of the angular velocity of the sphere and the velocity of the free stream. A set of linearized equations is derived from the governing ones, and these differential equations are solved numerically using the hybrid linearization–differential quadrature method. The surface shear stresses in the x- and y-directions and the surface heat transfer rate are improved due to the Casson βo, mixed convection α, rotation γ and magnetic field M parameters. In addition, as nanoparticles, the solid volume fraction (parameter ϕ) increases, and the surface shear stresses and the rate of heat transfer are raised. A comparison between earlier published data and the present numerical computations is presented for the limiting cases, which are noted to be in very good agreement.

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Effect of Nanofluid on Heat Transfer Enhancement for Mixed Convection Flow Over a Corrugated Surface

Journal of Non-Equilibrium Thermodynamics ◽

10.1515/jnet-2020-0008 ◽

2020 ◽

Vol 45 (4) ◽

pp. 373-383

Author(s):

Nepal Chandra Roy ◽

Sadia Siddiqa

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Nusselt Number ◽

Mixed Convection ◽

Local Nusselt Number ◽

Richardson Number ◽

Thermal Boundary Layer ◽

Volume Fraction ◽

Convection Flow ◽

Mixed Convection Flow

AbstractA mathematical model for mixed convection flow of a nanofluid along a vertical wavy surface has been studied. Numerical results reveal the effects of the volume fraction of nanoparticles, the axial distribution, the Richardson number, and the amplitude/wavelength ratio on the heat transfer of Al2O3-water nanofluid. By increasing the volume fraction of nanoparticles, the local Nusselt number and the thermal boundary layer increases significantly. In case of \mathrm{Ri}=1.0, the inclusion of 2 % and 5 % nanoparticles in the pure fluid augments the local Nusselt number, measured at the axial position 6.0, by 6.6 % and 16.3 % for a flat plate and by 5.9 % and 14.5 %, and 5.4 % and 13.3 % for the wavy surfaces with an amplitude/wavelength ratio of 0.1 and 0.2, respectively. However, when the Richardson number is increased, the local Nusselt number is found to increase but the thermal boundary layer decreases. For small values of the amplitude/wavelength ratio, the two harmonics pattern of the energy field cannot be detected by the local Nusselt number curve, however the isotherms clearly demonstrate this characteristic. The pressure leads to the first harmonic, and the buoyancy, diffusion, and inertia forces produce the second harmonic.

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G-jitter fully developed heat transfer by mixed convection flow of nanofluid in a vertical channel

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v13n3.647 ◽

2017 ◽

Vol 13 (3) ◽

Author(s):

Wan Nor Zaleha Amin ◽

Noraihan Afiqah Rawi ◽

Mohd Ariff Admon ◽

Sharidan Shafie

Keyword(s):

Heat Transfer ◽

Mixed Convection ◽

Base Fluid ◽

Volume Fraction ◽

Vertical Channel ◽

Convection Flow ◽

Physical Parameters ◽

Mixed Convection Flow ◽

Temperature Ratio ◽

Water Base

In this study, the effect of g-jitter fully developed heat transfer by mixed convection flow of nanofluid in a vertical channel is investigated. The nanoparticles of aluminum oxide and copper with water as a base fluid are used in this study. The equations corresponding to this study are solved analytically to find the exact solutions. The results of velocity and temperature profiles with the influence of physical parameters such as mixed convection, oscillation, temperature ratio and volume fraction of the nanoparticles are plotted and analyze in details. The behavior of steady state flow is also investigated. Results shown that as mixed convection, oscillation, and temperature ratio increased, the velocity profiles increased. The conductivity and viscosity of the nanofluid are also increased due to the increase of the volume fraction of nanoparticles in the water base fluid.

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Unsteady Mixed Convection Flow in the Stagnation Region of a Three Dimensional Body Embedded in a Porous Medium

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2008.13.1.14587 ◽

2008 ◽

Vol 13 (1) ◽

pp. 31-46 ◽

Cited By ~ 4

Author(s):

F. S. Ibrahim

Keyword(s):

Heat Transfer ◽

Mixed Convection ◽

Potential Flow ◽

Nodal Point ◽

Three Dimensional ◽

Convection Flow ◽

Physical Parameters ◽

Shear Stresses ◽

Mixed Convection Flow ◽

Unsteady Mixed Convection

An analysis is preformed to study the heat transfer characteristic of unsteady mixed convection flow of a viscous fluid in the vicinity of a stagnation point of a general three-dimensional body embedded in a porous media. The velocity in the potential flow is assumed to vary arbitrary with time. The non-Darcy effects including convective, boundary and inertial effects are included in the analysis. Both nodal-point region (0 ≤ c ≤ 1), where c = b/a is the ratio of the velocity gradients in y and x directions in the potential flow and saddle point region (−1 ≤ c < 0) are considered. The semisimilar solutions of the momentum and energy equations are obtained numerically using finite difference method. Also a self-similar solution is found when the velocity in the potential flow and the wall temperature vary with time in particular manner. Many results are obtained and a representative set is displayed graphically to illustrate the influence of the physical parameters on the surface shear stresses and the surface heat transfer.

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