generally, the porous media used in force convection to increase heat transfer, While it used in natural convection to decrease heat transfer (insulation).
Laith M. Jasim actually i need sth with high porosity (more than 85%) and high thermal conductivity (in the range of metals' properties) which can be used in the mentioned scale and could have enough stability against water liquid momentum.
Md. Washim Akram i appreciate u. but the thermal conductivity in ur suggested articles is too low and it can not be useful for heat transfer enhancement. thanks a lot.