This study integrates radiative equilibrium boundary conditions on a
catalytic surface within the Direct Simulation Monte Carlo (DSMC) method. The
radiative equilibrium boundary condition is based on the principle of energy
conservation at each surface element, enabling the accurate capture of
spatially varying surface temperatures and heat fluxes encountered during
atmospheric re-entry. The surface catalycity is represented through the
finite-rate surface chemistry (FRSC) model, specifically focusing on the
heterogeneous recombination of atomic oxygen on silica surfaces. Both the FRSC
model and the radiative equilibrium boundary conditions within the DSMC
framework are validated through comparison to analytical solutions. Numerical
simulations are conducted for rarefied hypersonic flow around a two-dimensional
cylinder under representative re-entry conditions for both non-catalytic and
catalytic surfaces. The results demonstrate significant discrepancies in
computed surface properties between the radiative equilibrium and conventional
isothermal boundary conditions. Furthermore, linear interpolation between
results from two independent isothermal boundary conditions is shown to be
inadequate for accurately predicting surface heat flux, particularly when
surface reactions are considered. The observed discrepancies originate from a
non-linear correlation between surface temperature and heat flux, influenced by
factors such as surface catalycity and local geometric variations along the
cylinder. These findings highlight the necessity of implementing radiative
equilibrium boundary conditions within DSMC to ensure physically accurate
aerothermodynamic computations.

Este artículo explora los viajes en el tiempo y sus implicaciones.

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