The complex geometry of carbon foam is enhanced by this microscopic imagery. Its unique high-temperature properties, high thermal shock resistance and dimensional stability make carbon foam ideal for thermal protection and thermal management systems. (U.S. Air Force photo)

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Carbon Foam Well Suited to Thermal Management

Published April 19, 2011
By Dr. Ajit Roy
Materials and Manufacturing

WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- Thermal management is critical to aerospace systems, and researchers at the Air Force Research Lab are tailoring carbon foam materials to enhance thermal protection in Air Force applications. Carbon foam materials are well suited to the task because of their unique high-temperature properties, high thermal shock resistance and dimensional stability. Ultra lightweight, thermally stable, multifunctional materials are critical in the development of thermal protection systems (TPS), thermal management systems (TMS) and heat exchangers.

Materials that can be tailored to carry, store, and shield thermal energy in an aerospace system improve performance while increasing speed and operational life. Carbon is an extremely tailorable material, with intrinsic attributes ideal for TPS and TMS. Carbon offers more stiffness than polymer foams and elastomers, and is lighter than many polymer and ceramic composites, elastomers, polymer foams and metals. Some varieties of carbon foam offer low temperature processing, which is ideal for insulating. Other processes yield carbon foam that can process high temperatures. The open-cell porosity of conductive carbon foam also offers a scaffolding microstructure for solid state thermal storage devices, significantly reducing the charging/decharging cycle time.

TPS-hybrid materials designed with embedded carbon foam of connected porosity will enable micro channel cooling of TPS sharp leading edge (tip diameter less than 0.02 inch)--existing technology of high-temp alloys cannot do this. Replacing metal heat exchangers with air-to-air heat exchanger designed with carbon foam provides a weight savings of 30 percent and doubles performance life.