Micro-scale thermal response modeling of an Avcoat-like TPS

Saurabh S. Sawant, Pooja Rao, Abhilash Harpale, Huck Beng Chew, Deborah A. Levin

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The present work describes the efforts to model a complex microstructure of an Avcoat-like material using direct simulation Monte Carlo (DSMC) method with correct boundary conditions, where a cross flow of boundary layer and pyrolysis species through the material can be simulated. To aid in choosing the gas pressures at the boundary, the development and verification of a continuum scale, finite volume solver is presented that models the gas phase in conjunction with the solid phase. To understand the thermal response of the microstructure, a hybrid random walk model is described, which has a capability to include convection, conduction, and radiation. With the help of these tools, the relative importance of heat transfer mechanisms is analyzed on a micron scale morphology. Using DSMC, the continuum permeability of 15.7×10−12 m2 is obtained for our microstructure model with 0.71 porosity. Furthermore, the flow through the microstructure during the process of pyrolysis is analyzed and the detailed collision statistics are reported as a function of depth. An estimate of collision statistics along an assumed trajectory is given to show the relative importance of gas-gas and gas-surface collisions. In addition, a way to scale the DSMC results on a small scale sample to larger depths is described. Finally, molecular dynamics (MD) simulations based on reactive-force-field (ReaxFF) potential are performed to elucidate the pyrolysis kinetics of a highly crosslinked phenolic formaldehyde resin.

Original languageEnglish (US)
Title of host publicationAIAA Aerospace Sciences Meeting
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624105241
StatePublished - 2018
EventAIAA Aerospace Sciences Meeting, 2018 - Kissimmee, United States
Duration: Jan 8 2018Jan 12 2018

Publication series

NameAIAA Aerospace Sciences Meeting, 2018


OtherAIAA Aerospace Sciences Meeting, 2018
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Aerospace Engineering


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