Mohamed Eissa Sayed-Ahmed

MHD flow and heat transfer in a rectangular duct with temperature dependent viscosity and hall effect

Abstract In the present paper the laminar fully developed MHD flow and heat transfer through a rectangular duct of a viscous incompressible electrically conducting fluid is studied. A constant pressure gradient and an external uniform magnetic field are applied and the Hall effect is taken into consideration. The fluid viscosity is assumed to be temperature dependent with the assumption of constant wall heat flux axially and constant wall temperature peripherally. A numerical solution for the governing non-linear partial differential equations is obtained. The effect of the Hall term and the variable viscosity on the velocity and temperature fields is examined.

Forced convection heat transfer of a Robertson-Stiff fluid between two coaxial rotating cylinders

Abstract Laminar flow and forced convection heat transfer of the time independent non-Newtonian fluid obeying Robertson-Stiff stress-strain relation have been investigated numerically in the annular space between two coaxial rotating cylinders. The problem is considered when the inner cylinder rotates about the common axis with constant angular velocity and the outer cylinder at the rest, and two cases of the third kind of the thermal boundary conditions. The tangential and axial momentum equations have been solved iteratively by using a finite difference method. Then the energy equation has been solved for the two cases. For the steady fully developed flow, the velocity distributions, temperature profiles, the average volumetric flow rate, torque and the average Nusselt numbers have been obtained for different values of the radius ratio and model parameters.

Unsteady Hydromagnetic Generalized Couette Flow of a Non-Newtonian Fluid With Heat Transfer Between Parallel Porous Plates

The unsteady magnetohydrodynamics flow of an electrically conducting viscous incompressible non-Newtonian Casson fluid bounded by two parallel nonconducting porous plates is studied with heat transfer considering the Hall effect. An external uniform magnetic field is applied perpendicular to the plates and the fluid motion is subjected to a uniform suction and injection. The lower plate is stationary and the upper plate is suddenly set into motion and simultaneously suddenly isothermally heated to a temperature other than the lower plate temperature. Numerical solutions are obtained for the governing momentum and energy equations taking the Joule and viscous dissipations into consideration. The effect of the Hall term, the parameter describing the non-Newtonian behavior, and the velocity of suction and injection on both the velocity and temperature distributions are studied.

Laminar fully developed flow and heat transfer for Robertson-stiff fluids in rectangular ducts with temperature defendent viscosity

Laminar fully developed flow and heat transfer for Robertson-Stiff fluids in rectangular ducts with temperature dependent viscosity is studied numerically. The viscosity is taken to vary exponentially with temperature. The effect of the temperature dependent viscosity on the behavior of the flow and the heat transfer is investigated. The coupled momentum and energy equations are solved iteratively using finite difference method to obtain the velocity, fanning friction factor and temperature distributions. The average Nusslet numbers are obtained for H 1 thermal boundary condition. Computations are obtained for different values of yield stress, flow index, aspect ratio and viscosity parameters