Thermal Spray Forming of High-efficiency Metal-foam Heat Exchangers

Thermal spray coating processes have been employed in the current study to deposit well-adhered, dense skins onto the surfaces of open-cell metal foams. The result is a channel that consists of a metal foam core and a thermal sprayed skin wall that can be used as a compact heat-exchanger by directing the coolant flow through the foam. To study the feasibility of the metallic foam heat-exchangers, hydraulic and heat-transfer characteristics were investigated experimentally. The local wall and fluid temperature distribution and the pressure drop along the length of the heat exchanger were measured for different coolant flow velocities. The Dupuit-Forchheimer modification is employed with the experimental results to determine flow characteristics. To measure the heat transfer performance, a length average Nusselt number is derived from a volumetric heat transfer coefficient based on the local wall and fluid temperatures. Heat transfer was shown to have increased nearly 7 times compared to that of a channel without a foam core.MAS