A.K. Abdul Hakeem

Natural convection in a square cavity due to thermally active plates for different boundary conditions

Abstract This work deals with the study of natural convection cooling of thermally active plates placed inside an air filled cavity at the center, with two different boundary conditions imposed on the cavity walls. By an active plate we mean one that is hotter due to isothermal heating or inherent heat generation. The walls of the cavity are subjected to either an isothermal temperature or a uniform outward heat flux. The finite difference method using the alternating direction implicit method coupled with the successive over-relaxation technique is employed to solve the governing nonlinear coupled equations. The results are presented and discussed in terms of a steady state isotherm and streamline plot, and over all Nusselt numbers. This study will provide qualitative suggestions that may improve the thermal design of sealed modern electronic packages which are encountered frequently in the electronics industry.

Hydromagnetic flow and radiative heat transfer of nanofluid past a vertical plate

Abstract Hydromagnetic flow of an incompressible viscous nanofluid past a vertical plate in the presence of thermal radiation is investigated both analytically and numerically. The radiative heat flux is described by the Rosseland diffusion approximation in the energy equation. The governing non-linear partial differential equations are converted into a set of ordinary differential equations by suitable similarity transformations. The resulting ordinary differential equations are successfully solved analytically with the help of homotopy analysis method and numerically by the fourth order Runge–Kutta method with shooting technique. The effects of various physical parameters are analyzed and discussed in graphical and tabular forms. The effects of some physical parameters such as Lewis number, Prandtl number, buoyancy ratio, thermophoresis, Brownian motion, radiation parameter and magnetic parameter are analyzed on the velocity, temperature and solid volume fraction profiles as well as on the reduced Nusselt number and the local Sherwood number. An excellent agreement is observed between present analytical and numerical results.

SECOND LAW ANALYSIS ON RADIATIVE SLIP FLOW OF NANOFLUID OVER A STRETCHING SHEET IN THE PRESENCE OF LORENTZ FORCE AND HEAT GENERATION/ABSORPTION

In this article, we analyzed the second law of thermodynamics applied to an electrically conducting incompressible water based nanofluid flow over a stretching sheet in the presence of thermal radiation and uniform heat generation/absorption both analytically and numerically. The basic boundary layer equations are non-linear PDEs which are converted into non-linear ODEs using scaling transformation. The dimensionless governing equations for this investigation are solved analytically using hypergeometric function and numerically by the fourth order Runge Kutta method with shooting iteration technique. The effects of partial slip parameter with the nanoparticle volume fraction, magnetic parameter, radiation parameter, uniform heat generation/absorption parameter, suction parameter, dimensionless group parameter, Hartmann number and Reynolds number on the entropy generation are discussed for various nanoparticles such as Cu, Ag, Al2O3 and T iO2. It is found that the entropy generation enhances with the increase of magnetic parameter and Hartmann number and decreases with slip parameter.