Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. This type of ablative material is composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Then, as the temperature rises, the surface of the porous matrix recess through ablative processes. For re-entry conditions typical of space exploration missions, this is mainly diffusion limited oxidation. However, recent studies have shown that oxygen from the atmosphere actually penetrates a thin layer of the porous material, oxidizing the carbon fibers from within.
This research activity presents a volume-averaged fiber-scale oxidation model, based on the one previously developed by Lachaud et al. The present model, however, solves the momentum equation as well as the energy equation. Results based on a an experimental test case are presented. The importance of solving both equations is clearly demonstrated, and a new value for carbon fiber oxidation reactivity is suggested.
Digital Object Identifier (DOI)
Martin, Alexandre, "Volume Averaged Modeling of the Oxidation of Porous Carbon Fiber Material" (2013). Mechanical Engineering Faculty Publications. 13.