Coal-Based Porous Graphite for Aerospace Heat Exchanger Applications

A newly developed "coal-based" porous graphite material has been recently produced. This development is a direct result of Touchstone Research Laboratory's Phase I funding to develop enhanced-strength carbon foam heat-exchanger materials for aerospace applications since low density carbon foams cannot endure high bleed air pressures in aerospace pre-coolers and heat exchangers. The newly developed material indicates compressive strength of ~ 6000 psi in comparison with 200-700 psi for graphite foam. In addition, the porous graphite has 3 times the thermal conductivity (55 W/m·K) of Inconel and significantly lower CTE indicating ~3.5 (1/°C), which should be beneficial in reducing thermal stress and improving durability. Preliminary investigations show there will be no added costs related to the production of coal-based porous graphite since similar production methods are employed in the manufacture of other CFOAMr products lines. This makes coal-based porous graphite extremely affordable relative to any other carbon and graphite currently on the market. Touchstone and its partners propose to fabricate a heat exchanger core from porous graphite for pressure drop, heat flow and durability evaluations, which will ultimately lead to the construction of highly efficient, lightweight, and affordable replacements to current heat exchanger technologies in aerospace.