Nanoporous metallic surface: Facile fabrication and enhancement of boiling heat transfer

We start with the simplest case, that of zero flow through the fluid-saturated porous medium. For an equilibrium state, the momentum equation is satisfied if

$$ - \nabla P + {{\rho}_{\mathrm{ f}}}g = 0. $$

Internal Natural Convection: Heating from Below

To investigate the convection in a porous medium, a horizontal quiescent layer of one fluid saturating a porous medium heated from bottom is numerically studied using single lattice-Boltzmann method (LBM) and the generalized Navier?Stokes equation proposed by Nithiarasu et al. [P. Nithiarasu, K.M. Seetharamu, and T Sundararajan Int. J. Heat Mass Trans. 40 (1997) 3955]. Due to the rarefaction, the boundary conditions are considered as both temperature jump and velocity slip. The computational results are validated against the analytical results, and excellent agreement has been obtained. The results have shown that the Rayleigh number is increased with increasing temperature jump, the stabilization effect of temperature is much more significant than that of velocity slip, and the computation stability of present model is better than that of Darcy and Brinkman models.

http://iopscience.iop.org/article/10.1088/0253-6102/49/5/51/pdf

Lattice Boltzmann Simulation of Convection in a Porous Medium with Temperature Jump and Velocity Slip Boundary Conditions

Some modelling deficiencies in various recent papers, on convective flows in porous media, are pointed out and discussed. These deficiencies are related to the Forchheimer coefficient, mixed double-diffusive convection, magnetohydrodynamic mixed convection, convection in a rarefied gas, and geophysical phenomena.

Some Pitfalls in the Modelling of Convective Flows in Porous Media

The present work is concerned with the effects of surface slip conditions and thermal radiation on an electrically conducting fluid over a non-isothermal stretching surface in the presence of a uniform transverse magnetic field. Similarity transformation is used to transform the partial differential equations describing the problem into a system of nonlinear ordinary differential equations, which is solved analytically. The effects of various parameters on the velocity and temperature profiles as well as on the local skin-friction and the local Nusselt number are discussed in detail and displayed through graphs.

Mhd flow and heat transfer in a viscous fluid over a non-isothermal stretching surface with thermal radiation in slip-flow regime

The onset of convection in a rarefield gas saturating a horizontal layer of a porous medium has been investigated using both Darcy and Brinkman models. It is assumed that due to rarefaction both velocity slip and temperature jump exist at the boundaries. The results show that (i) when the degree of rarefaction increases the critical Rayleigh number as well as the critical wave number for the onset of convection increases, (ii) stabilizing effect of temperature jump is more than that of velocity slip, (iii) Darcy model is seen to be the most stable one when compared to Brinkman model or the pure gaseous layer (i.e. in the absence of porous medium).

C. Parthiban

Papers

Convection in a porous medium with velocity slip and temperature jump boundary conditions