Natural convection in water-saturated reticulated vitreous carbon foam

Experiments of the Horton–Rogers–Lapwood type are reported for water-saturated, 97% porous reticulated vitreous carbon foam. Heat transfer data have been obtained for layer aspect ratios of 2.5 and 5, porous medium Rayleigh numbers from 140 to 4700, and Darcy numbers from 5 × 10−5 to 37 × 10−5. The data are well correlated in the form Num=(0.007±0.002)Ram0.504±0.06Prp0.41±0.08.Conduction through the solid phase plays a limited role, and the main heat transfer mechanism is advection. Correlation of the present data and water-saturated copper foam data [1] is achieved by inclusion of the conductivity ratio to give, Num=(0.008±0.003)kmkf0.25±0.04Ram0.50±0.02Prp0.38±0.04.