Simulation of an Aluminum Foam Heat Exchanger Using the Volume Averaging Technique

Open cell metal foams show a high potential for heat transfer applications. In this paper the thermal and hydraulic performance of a metal foam heat exchanger with two tube rows in a staggered layout is studied. Two-dimensional simulations are performed using a bulk model based on the volume averaging technique. A louvered fin heat exchanger with the same tube layout and overall volume is considered as reference case. Velocities range from 1.2 m/s to 3.2 m/s. An experimental validation illustrates the quality of the simulation results. For the same fan power, the 10 ppi and 20 ppi foams show a smaller heat transfer than the louvered fin heat exchanger. This is mainly due to the larger airside heat transfer surface area of the louvered fin heat exchanger (because of the small fin pitch) compared to the foams. 30 and 35 ppi foams, having a specific surface area above 1000 m2/m3, show a better thermal hydraulic performance than the louvered fin design.