Foam Heat Exchangers: A Technology Assessment

Open-cell porous metal foams have received attention for use in compact heat exchangers due to their increasing availability and improved thermal performance. In recent years, considerable research has been conducted on use of metallic and nonmetallic foams to further improve performance of state-of-the-art heat exchangers. In this paper, we report preliminary results from fabrication, development and experimental investigation of thermal-hydraulic performance of high-temperature metal foam heat exchangers for automotive exhaust gas recirculation (EGR) system. A brief review of nickel–chromium and stainless-steel foam heat exchanger technology and of recent efforts on their manufacturing techniques for a liquid-to-air heat exchange application is presented. Measured heat transfer and pressure drop data for foam heat exchangers and their comparison with performance of a conventional wavy plate-fin heat exchanger are discussed. Technical challenges and risks associated with foam heat exchangers are discussed, along with recommendations for future development.