Emad M. Abo-Eldahab

Hall current effect on magnetohydrodynamic free-convection flow past a semi-infinite vertical plate with mass transfer

Abstract Heat and mass transfer along a vertical plate under the combined buoyancy force effects of thermal and species diffusion is investigated in the presence of a transversely applied uniform magnetic field and the Hall currents are taken into account. The governing fundamental equations on the assumption of small magnetic Reynolds number are approximated by a system of nonlinear ordinary differential equations, which are integrated by fourth-order Runge–Kutta method. Velocity, temperature and concentration are shown on graphs. The numerical values of the local shear stress, the local Nusselt number Nu and the local Sherwood number Sh are entered in Table 1 . The effects of magnetic parameter, Hall parameter and the relative buoyancy force effect between species and thermal diffusion on the velocity, temperature and concentration are discussed. The results are compared with those known from the literature.

Flow and heat transfer in a micropolar fluid past a stretching surface embedded in a non-Darcian porous medium with uniform free stream

Heat transfer from a stretching iso-thermal surface embedded in a non-Darcian medium to a micropolar fluid in the presence of a uniform transverse magnetic field is analyzed. The surface is linearly stretched in the presence of a uniform free stream of constant velocity and temperature. The effect of internal heat generation/absorption is also considered. The governing equations of momentum, angular momentum and energy are solved numerically. Numerical results are shown in tabular form and graphically for the velocity, angular velocity and temperature distributions as well as the skin-friction and wall heat transfer rate and discussed for various physical parametric values.

Radiation effect on heat transfer of a micropolar fluid through a porous medium

Radiation effect on heat transfer of a micropolar fluid past unmoving horizontal plate through a porous medium is considered. Numerical solutions for the governing boundary layer equations obtained by applying an efficient numerical technique based on the shooting method. This solution studied for a range of values of permeability, vortex-viscosity and radiation parameters. The effects of these parameters examined on the velocity distribution of fluid, temperature distribution and angular velocity of microstructures as well as the coefficient of heat flux and shearing stress at the plate.

HALL CURRENT AND OHMIC HEATING EFFECTS ON MIXED CONVECTION BOUNDARY LAYER FLOW OF A MICROPOLAR FLUID FROM A ROTATING CONE WITH POWER-LAW VARIATION IN SURFACE TEMPERATURE

The problem of laminar mixed convection boundary layer flow of an electrically conducting micropolar fluid from a constantly rotating cone is analyzed, taking into account the effects of Hall current and Ohmic heating. The flow is subjected to a uniform strong transverse magnetic field normal to the cone surface. In this study, the surface temperature is assumed to vary as a power of the axial coordinate measured along the cone surface. A non-similar mixed convection parameter and a pseudo-similarity variable η are introduced to cast the governing boundary layer equations into a system of dimensionless equations, which are solved numerically. The mixed convection parameter is chosen to cover the entire regime of mixed convection from the pure forced limit to the pure free convection limit. Results for the velocity, angular velocity and thermal functions are displayed for a range of values of magnetic parameter, Hall parameter and Eckert number

Radiation effect on heat transfer in an electrically conducting fluid at a stretching surface with a uniform free stream

The problem of free convection heat transfer characteristics in an electrically conducting fluid is investigated near an isothermal sheet. This has been done under the combined effect of buoyancy and radiation in the presence of a transverse magnetic field. The sheet is linearly stretched in the presence of a uniform free stream of constant velocity and temperature. The effect of internal heat generation or absorption is also considered. The resulting coupled nonlinear differential equations are solved numerically. A parametric study is performed to illustrate the influence of the radiation parameter, magnetic parameter and heat generation or absorption parameter on the profiles of the velocity and temperature functions. Numerical data for the skin friction and the heat flux functions have been tabulated for various parametric conditions. The results are compared with those known from the literature.

Convective heat transfer in an electrically conducting micropolar fluid at a stretching surface with uniform free stream

The problem of convective heat transfer for a micropolar fluid in the presence of uniform magnetic field is investigated near an isothermal-stretching sheet. This has been done under the effect of buoyancy force. The sheet is linearly stretched in the presence of a uniform free stream of constant velocity and temperature. Numerical solutions for the governing boundary layer equations for a range of values of magnetic, vortex viscosity and microrotation parameters, also, Grashoff number obtained by applying an efficient numerical technique based on shooting method. The effects of these parameters examined on the velocity of fluid, temperature distribution and angular velocity of microstructures as well as the coefficient of heat flux and shearing stress at the plate.

MHD free-convection flow of a non-Newtonian power-law fluid at a stretching surface with a uniform free-stream

The momentum and heat transfer in laminar boundary layer of a non-Newtonian power-law fluid flowing past a stretching surface with uniform surface heat flux and uniform free-stream, are analyzed. The sheet is linearly stretched in the presence of a uniform transverse magnetic. The effect of internal heat generation or absorption is also considered. The governing similar equations are solved numerically for several values of the power-law viscosity index and the non-Newtonian Prandtl number of the fluid. A discussion is provided for the effect of the magnetic field and heat source/sink parameters on the velocity and temperature fields. Friction coefficients and Nusselt number are calculated for the mentioned parameters.

Radiation Effect on MHD Free Convection Flow of a Gas Past a Semi-infinite Vertical Plate with Variable Viscosity

The radiation effect in the presence of a uniform transverse magnetic field on steady free convection flow with variable viscosity is investigated. The fluid viscosity is assumed to vary as the reciprocal of a linear function of temperature. Boundary layer equations are derived. The resulting approximate non-linear ordinary differential equations are solved linearly and nonlinearly by shooting methods. The velocity and temperature profiles are shown, and the skin friction on the plate and heat transfer coefficient are presented and discussed. The results of the present study show that in the presence of magnetic field, as the radiation parameter increases the temperature increases, but the velocity decreases.