Multi-scale thermal response modeling of an AVCOAT-like thermal protection material

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

Research output: Contribution to journalArticle

Abstract

A multi-scale modeling approach based on the stochastic Direct Simulation Monte Carlo (DSMC) and walker methods is developed to understand the complex flows and thermophysical phenomena through a syntactic foam TPS, similar to AVCOAT. Using novel, unstructured adaptive mesh refinement/Octree grids and newly developed subsonic boundary conditions, the counter-flow transport of boundary layer and pyrolysis gases through the porous microstructure is modeled for the first time. Permeability of the microstructure models having porosities of 0.71 and 0.86 is computed in the DSMC simulations and compared to a fibrous TPS material. The rigorous development of a stochastic based thermal response model that can couple convective, conductive, and radiative heat transfer through a porous material having non-uniform thermophysical properties and high temperature gradients is presented and compared with a one-dimensional finite-volume approach. The material thermal response is found to be dominated by conduction, yet, the interactions between boundary layer and pyrolysis species on the actual 3-D geometry, which cannot be considered in traditional material response solvers, may in fact cause them to underpredict the TPS material temperature.

Original languageEnglish (US)
Pages (from-to)1176-1195
Number of pages20
JournalInternational Journal of Heat and Mass Transfer
Volume133
DOIs
StatePublished - Apr 2019

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Keywords

  • Ablation
  • Conduction
  • DSMC
  • Gas-gas collisions
  • Gas-surface interactions
  • Material thermal response
  • Permeability
  • Porous media
  • Pyrolysis
  • Radiation
  • Random walk
  • Thermal protection system

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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