Md. Abdul Hakim Khan

Finite element analysis of double-diffusive natural convection in a porous triangular enclosure filled with Al2O3-water nanofluid in presence of heat generation

The problem of double-diffusive natural convection of Al2O3-water nanofluid in a porous triangular enclosure in presence of heat generation has been studied numerically in this paper. The bottom wall of the cavity is heated isothermally, the left inclined wall is non-isothermal and the right inclined wall is considered to be cold. The concentration is higher at bottom wall, lower at right inclined wall and non-isoconcentration at left inclined wall of the cavity. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The results are obtained in terms of streamlines, isotherms, isoconcentrations, average Nueeslt number (Nu) and average Sherwood number (Sh) for the parameters thermal Rayleigh number (RaT), dimensionless heat generation parameter (λ), solid volume fraction (ϕ) and Lewis number (Le) while Prandtl number (Pr), Buoyancy ratio (N) and Darcy number (Da) are considered to be fixed. It is observed that flow pattern, temperature fields and concentration fields are affected by the variation of above considered parameters.

Magneto-Nanofluid Dynamics in Convergent-Divergent Channel and its Inherent Irreversibility

The effects of Cu-nanoparticles on the entropy generation of steady magnetohydrodynamic incompressible flow with viscous dissipation and Joule heating through convergent-divergent channel are analysed in this paper. The basic nonlinear partial differential equations are transformed into a system of coupled ordinary differential equations using suitable transformations which are then solved using power series with Hermite- Padé approximation technique. The velocity profiles, temperature distributions, entropy generation rates, Bejan number as well as the rate of heat transfer at the wall are presented in convergent-divergent channels for various values of nanoparticles solid volume fraction, Eckert number, Reynolds number and channel angle. A stability analysis has been performed for the shear stress which signifies that the lower solution branch is stable and physically realizable, whereas the upper solution branch is unstable. It is interesting to remark that the entropy generation of the system increases at the two walls as well as the heat transfer irreversibility is dominant there whereas the fluid friction irreversibility is dominant along the centreline of the channel.

Instability of Variable Thermal Conductivity Magnetohydrodynamic Nanofluid Flow in a Vertical Porous Channel of Varying Width

A numerical investigation is performed into the heat transfer and entropy generation of a variable thermal conductivity magnetohydrodynamic flow of Al2O3-water nanofluid in a vertical channel of varying width with right porous wall, which enable the fluid to enter. The effects of the Lorentz force, buoyancy force, viscous dissipation and Joule heating are considered and modeled using the transverse momentum and energy balance equations respectively. The governing nonlinear partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using power series with Hermite-Padé approximation method. A stability analysis has been performed for the local rate of shear stress and Nusselt number that indicates the existence of dual solution branches. Numerical results are achieved for the fluid velocity, temperature as well as the rate of heat transfer at the wall and the entropy generation of the system. The present results are original and new for the flow and heat transfer past a channel of varying width in a nanofluid which shows that the physical parameters have significant effects on the flow field.

Natural convective heat and mass transfer in a porous triangular enclosure filled with nanofluid in presence of heat generation

The problem of natural convective heat and mass transfer in a triangular enclosure filled with nanofluid saturated porous medium in presence of heat generation has been studied in this paper. The bottom wall of the cavity is heated uniformly, the left inclined wall is heated linearly and the right inclined wall is considered to be cold. The concentration is higher at bottom wall, lower at right inclined wall and linearly concentrated at left inclined wall of the cavity. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The results are obtained in terms of streamline, isotherms, isoconcentrations, Nusselt number (Nu) and Sherwood number (Sh) for the parameters thermal Rayleigh number (RaT), Heat generation parameter (λ) and Lewis number (Le) while Prandtl number (Pr), Buoyancy ratio (N) and Darcy number (Da) are considered to be fixed. It is observed that flow pattern, temperature fields and concentr...