A Kinetic Monte Carlo based analysis of graphite oxidation with realistic defect distributions

Simon Schmitt, Alexandre Martin

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

A coarse-grained kinetic oxidation mechanism is developed and implemented in a Kinetic Monte Carlo simulation framework, that allows to simulate pitting of large carbon surfaces up to micrometer lengthscales. The mechanism is validated on the basis of single pit growth. We further study more realistic defected carbon structures, where multiple pits interact with each other, as well as with grain boundaries present in the graphite structure. For two merging pits, the KMC results agree with an analytic model derived for the evolution of active sites that contribute to the reactivity of the carbon surface. The KMC results on more complex defect structures, including grain boundaries, reveal several characteristics of the dynamic evolution of the carbon surface reactivity. One of those is the possibility of an equilibrium state of the pitted carbon surface with respect to its effective reactivity on a single grain basis. We use this finding to build a model for the active site density on a pitted HOPG surface, which provides a theoretical foundation for the choice of active site density in modern finite-rate chemistry models used to predict gas-surface interactions on carbon ablators.

Original languageEnglish
Title of host publicationAIAA AVIATION 2022 Forum
DOIs
StatePublished - 2022
EventAIAA AVIATION 2022 Forum - Chicago, United States
Duration: Jun 27 2022Jul 1 2022

Publication series

NameAIAA AVIATION 2022 Forum

Conference

ConferenceAIAA AVIATION 2022 Forum
Country/TerritoryUnited States
CityChicago
Period6/27/227/1/22

Bibliographical note

Publisher Copyright:
© 2022, American Institute of Aeronautics and Astronautics Inc, AIAA., All rights reserved.

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Nuclear Energy and Engineering
  • Aerospace Engineering

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