Effect of HBr on Explosion Limits of Stoichiometric Hydrogen‐oxygen Mixture

This work, based on numerical simulations, discusses the effect of HBr as an inhibitor on the explosion limit of stoichiometric hydrogen-oxygen gas mixture in a closed spherical vessel. The numerical simulation solves the complete governing equations for mass, momentum, species and energy. In addition, wall surface reactions are included to describe the destruction of chemically reactive radicals. The in-house INSFLA code is used, which takes into account the differential diffusion and thermal diffusion (Soret effect) to describe the mass transport of species within the system. The inhibitory effect of HBr on all three explosion limits under the considered conditions is analyzed based on sensitivity analysis of the explosion limit with respect to chemical reaction rates and reaction pathway analysis. It is found that the main reason for the inhibition effect is the chain-propagating step HBr+H -> Br+h$_2$ which is in effect terminating. However, each of the three explosion limits is governed by different key reactions.