Macroscopic correlation for natural convection in water saturated metal foam relative to the placement within an enclosure heated from below

Natural convection in water saturated metal foams is explored though experiments and numerical simulations. From these data a new generalized heat transfer correlation is developed for saturated metal foam with superposed water layers heated from below with arbitrary placement of the foam with respect to the bounding heated and cooled surfaces. The macroscopic correlation allows prediction of heat transfer with known or easily measurable properties of the foam. For Rayleigh numbers from 10⁶ to 10⁸, water saturated copper foam enhances heat transfer compared to pure water when the foam is adjacent to the heated or cooled boundary, but immersion of the foam without contact with the boundary provides no benefit. The enhancement of heat transfer is attributed primarily to conduction.