Experimental heat transfer due to oscillating water flow in open-cell metal foam

•Experimental heat transfer due to oscillating water flow in metal foam is presented.•Kinetic Reynolds numbers: 1873 and 5619; displacements: 1.5, 1.9 and 2.2 pipe diameters.•Cycle-averaged Nu behaves similar to water flow in packed spheres and air flow in foams.•For the higher frequency, cycle-averaged Nu was higher for higher displacement.

While studies concerning heat transfer due to oscillating air (and few other gases) flow in metal foam are available, heat transfer due to oscillating water flow in metal foam has not been offered in the literature. This paper presents characteristics of heat transfer of oscillating water flow in commercial open-cell metal-foam pipe that were obtained experimentally, most likely for the first time. One main difference between gas and liquid flows in porous media is that dispersion is far more significant in the latter. Another difference is the length of the entrance region, which depends strongly on the Prandtl number. The trends in the cycle-averaged wall temperature, length-averaged wall temperature and cycle-averaged Nusselt number were similar to those for oscillating water flow in packed spheres and for oscillating air flow in aluminum, copper and graphite foams in a rectangular channel. For the higher flow frequency of the current study, the cycle-averaged Nusselt number was higher for higher flow displacement amplitude.