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Variable viscosity and thermal conductivity effects on heat transfer by natural convection from a cone and a wedge in porous media

Hassanien I. A., Essawy A. H., Moursy N. M.

Archives of Mechanics

2003

Vol. 55, nr 4

345-356

The problem of steady, laminar heat transfer by natural convection flow over a vertical cone a wedge embedded in a uniform porous medium with variable viscosity and thermal conductivity is investigated. The transformed governing equations are solved numerically by using a finite difference scheme. The obtained results are compared with earlier papers on special cases of the problem and are found to be in excellent agreement. The influence of porous medium inertia effect, viscosity wariation parameter ... and thermal conductivity variation parameter ... on the fluid velocity and temperature is discussed. Including the porous medium inertia effect or viscosity variation parameter in the mathematical model is predicted to reduce the local Nusselt number. Furthermore, the local Nusselt number increases in the presence of thermal conductivity variation parameter.

Variable viscosity effects on combined heat and mass transfer by free convection over a truncated cone in porous media: UWT/UWC

Hassanien I. A., Essawy A. H., Moursy N. M.

Mechanics and Mechanical Engineering

2002

Vol. 6, nr 1

51-61

An analysis is presented is to study the beat and mass transfer characteristics of natural convection flow about a truncated cone embedded in a saturated porous medium with uniform surface temperature/concentration under the combined buoyancy effects thermal and mass diffusion. The transformed governing equations are solved by Keller box method. Numerical results for dimensionless temperature and concentration; the local Nuss elt (Sherwood) numbers are presented over a wide range of dimensionless distance ξ, Lewis number Le, buoyancy ratio N and the wall to ambient viscosity ratio v∗. It has been found that the local Nusselt number and Sherwood number decrease with decreasing the wall to ambient viscosity ratio v∗. Furthermore, it is shown that the local Nusselt (Sherwood) numbers of the truncated cone approach those of inclined plate (full cone) for the case of constant viscosity at ξ = 0 (ξ → ∞).