Multi-scale fusion study of atomic oxygen catalytic recombination on ZrB₂/SiC ultra-high temperature ceramics for aerodynamic heating prediction

ZrB₂-SiC thermal protection composite is a representative of promising ultra-high-temperature ceramics materials for future high-speed aircraft. The recombination reaction of dissociated oxygen atoms (AO), also termed as surface catalysis, is exothermic and can influence significantly the aerodynamic heat prediction. This work proposes a global Bayesian maximum entropy (GBME) multiscale fusion model to integrate the oxygen recombination coefficients derived from the reactive molecular dynamics (RMD) method and the experimental results at the macroscale. The obtained AO recombination coefficients and distribution patterns of surface oxides of ZrB₂-SiC composites with temperature variation are in good agreement with experimental observations, demonstrating the effectiveness of this method in achieving multiscale and multisource data fusion. For verification of the proposed multiscale fusion approach, numerical simulations are conducted to obtain the surface heat flux distribution on a blunt body by employing the proposed multi-scale finite-rate surface catalytic model, and the relative error of heat flux calculated from the GBME model compared with experiment is significantly reduced from 53.1 % to 16.7 %.