Hamzeh M. Duwairi

Effect of thermophoresis particle deposition on mixed convection from vertical surfaces embedded in saturated porous medium

Purpose – The aim of this paper is to formulate and analyze thermophoresis effects on mixed convection heat and mass transfer from vertical surfaces embedded in a saturated porous media with variable wall temperature and concentration.Design/methodology/approach – The governing partial differential equations (continuity, momentum, energy, and mass transfer) are written for the vertical surface with variable temperature and mass concentration. Then they are transformed using a set of non‐similarity parameters into dimensionless form and solved using Keller‐box method.Findings – Many results are obtained and a representative set is displaced graphically to illustrate the influence of the various physical parameters. It is found that the increasing of thermophoresis constant or temperature differences enhances heat transfer rates from vertical surfaces and increases wall thermophoresis velocities; this is due to favorable temperature gradients or buoyancy forces. It is also found that the effect of thermopho...

TRANSIENT MIXED CONVECTION ALONG A VERTICAL PLATE EMBEDDED IN POROUS MEDIA WITH INTERNAL HEAT GENERATION AND OSCILLATING TEMPERATURE

The effects of oscillating plate temperature on transient mixed convection heat transfer from a porous vertical surface embedded in a saturated porous medium with internal heat generation or absorption are studied. The governing equations are transformed into dimenionless form by a set of variables and solved using the Galerkine finite element method. As the energy generation increases, the temperature near the wall will be higher than the wall temperature, thus increasing buoyancy forces inside the boundary layer and consequently increasing the velocity. The increase of energy absorption term for either space or temperature dependence will decrease the velocity inside the boundary layer and increase heat transfer rates. Different temperature and velocity profiles are drawn for different dimensionless groups. Numerical values for Nusselt numbers as well as local skin friction coefficient are also tabulated.

Thermophoresis particle deposition — thermal radiation interaction on mixed convection from vertical surfaces embedded in porous medium

This work deals with thermophoresis particle deposition and thermal radiation interaction on mixed convection heat and mass transfer by steady laminar boundary-layer flow over a nonisothermal vertical flat plate embedded in a fluid- saturated porous medium. The governing partial-differential equations are transformed into nonsimilar form by using a spe- cial transformation and then solved numerically by using an implicit finite-difference method. Different results are ob- tained and displayed graphically to explain the effect of various physical parameters on the wall thermophoretic deposition velocity, Nusselt numbers, and temperature and concentration profiles. It was found that the increasing of radiation param- eter or dimensionless temperature ratio heated the fluid and decreased the temperature gradients near the impermeable wall, which increased the local Nusselt numbers and decreased the wall thermophoresis velocities. It was also found that the effect of power indexes of either temperatures or concentration enhances both local Nusselt numbers and wall thermo- phoresis velocities. Comparison with previously published work in the limits of absent thermophoresis and thermal radia- tion effects shows excellent agreement.

Thermophoresis particle deposition – thermal radiation interaction on natural convection heat and mass transfer from vertical permeable surfaces

Purpose – The purpose of this paper is to study thermophoresis particle deposition and thermal radiation interaction on natural convection heat and mass transfer by steady boundary layer flow over an isothermal vertical flat plate embedded in a fluid saturated porous medium.Design/methodology/approach – The governing partial differential equations are transformed into non‐similar form by using special transformation and then the resulting partial differential equations are solved numerically by using an implicit finite difference method.Findings – Different results are obtained and displaced graphically to explain the effect of various physical parameters on the wall thermophoresis deposition velocity and concentration profiles. It is found that the increasing of thermal radiation parameter or dimensionless temperature ratio heats the fluid and decreases temperature gradients near permeable wall, which increases local Nusselt numbers and decreases wall thermophoresis velocities. It is also found that the ...