This paper investigates the flow boiling characteristics of water and FC-72 in aluminum foams. For the experiments, the heat transfer processes prior to nucleate boiling, the onset of nucleate boiling and the hysteresis effect were studied. The temperature jump, marking the transition from nucleate to film boiling was observed for FC-72. Numerical simulations were performed based on water to compare with the experiments. In the single-phase simulations, the Brinkman-Forchheimer and local thermal non-equilibrium models were adopted for the momentum and energy equations, respectively while in the two-phase simulations, the two-phase mixture model was used. Comparisons between the experimental and numerical results show reasonable agreement. (C) 2011 Elsevier Ltd. All rights reserved.