Modeling the oxidation of low-density carbon fiber material based on micro-tomography

Joseph C. Ferguson, Francesco Panerai, Jean Lachaud, Alexandre Martin, Sean C.C. Bailey, Nagi N. Mansour

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Oxidation is one of the main decomposition mechanisms of fibrous carbon/phenolic ablators employed in thermal protection systems for planetary entry capsules. The oxidation process is driven by two competing mechanisms: diffusion of reactants within the porous medium, and reaction rates at the surface of the fibers. These mechanisms are characterized by the Thiele number. Given that the Thiele number varies during an atmospheric entry, we aim to understand the effects of the diffusion/reaction processes on the decomposition of a porous carbon material in various regimes. We use a particle method for simulations of the oxidation process at microscale. The movement of oxygen reactants is simulated using a Brownian motion technique, and heterogeneous first-order reactions at the surface are modeled with a sticking probability law. To enable simulations of the fiber decomposition on actual materials, we use digitized computational grids obtained using X-ray micro-tomographic imaging. We present results for the oxidation of the substrate of the material used on the Mars Science Laboratory capsule that landed the Curiosity rover. We find that the depth of the reaction zone for this material is critically dependent on the Thiele number.

Original languageEnglish
Pages (from-to)57-65
Number of pages9
JournalCarbon
Volume96
DOIs
StatePublished - Jan 2016

Bibliographical note

Funding Information:
The authors are indebted to T.A. Sandstrom for his assistance in the development of the PuMA framework. A.A. McDowell and D.Y. Parkinson are gratefully acknowledged for their help in the LBNL/NASA Ames collaboration on micro-CT measurements. This work was performed under the Entry System Modeling Project (M.J. Wright project manager) of the NASA Game Changing Development (GCD) Program. The work was partly supported by NASA SBIR Phase II Award NNX10CC53P , NASA and Kentucky EPSCoR Award NNX13AN04A , NASA Award NNX14AI97G , and NASA Kentucky under NASA Award NNX10AL96H . The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 .

Publisher Copyright:
© 2015 Elsevier Ltd.

Keywords

  • Carbon fibre
  • Micro-tomography
  • Oxidation

ASJC Scopus subject areas

  • Chemistry (all)
  • Materials Science (all)

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