Novel Heat Exchanger Materials for Fuel-Air Cooler Heat Exchanger

Open cell foam, which provides the highest heat transfer surface areas per unit volume, is considered as an excellent heat exchanger core material. Pyrolytic Carbon coated reticulated vitreous carbon (RVC) foam, developed by Allcomp, which offers highly conductive foam ligaments and is available in different pore sizes and density, provides wide design options. A hybrid heat exchanger composed of carbon foam as heat transfer core and metallic parting sheet can provide efficient heat transfer performance, acceptable pressure drop, sound structure that is compatible with external ducting, and meet leak tightness required for a fuel-air heat exchanger. Under this program, we plan to further optimize existing RVC based carbon foams to achieve improved thermal performance with minimum impact on the flow resistance. We also plan to further improve the reliability of joining between carbon foam and aluminum parting sheet meeting both thermal and structural requirements.  Finally, analytical models will also be developed based on experimental data to guide prototype design. A full-size return fuel-air cooler (RFAC) heat exchanger will be designed, fabricated and tested at end of the program. BENEFIT: A successful demonstration and qualification of a hybrid heat exchanger using open cell RVC foam and aluminum parting sheet for fuel-air heat exchanger will open up many design opportunities for other military and commercial heat exchanger applications.