A novel framework for modeling hydrogen convection-diffusion-heat-reaction coupling transport in evolving three dimensional porous fibrous materials across rarefied to continuum regimes

Gas catalytic reaction in porous materials is integral to the chemical industry. A novel reactive direct simulation Monte Carlo model is proposed to investigate the hydrogen gas reaction in three dimensional porous fibrous materials with flow state across from rarefied to continuum regimes. Complicated processes involving mass, gas flow, heat transfer, radiation effect, and evolving process of the solid skeleton within chemical reactions can be considered simultaneously. The effects of catalyst coverage and gas ratio on heat and mass transfer in the evolved porous fibrous materials are investigated. Results show that the porous fibrous skeleton evolution results in an increase in temperature compared to the scenarios neglecting skeleton evolution across rarefied to continuum regimes. The temperature increases with an increase in catalyst coverage and inlet hydrogen content. Both chemical reaction heat induced by gas molecules and skeleton evolution rate are contributed to the temperature rise within porous fibrous materials. A formula is derived to accurately and efficiently predict the effect of various factors on the temperature in porous fibrous materials. Above findings can improve the understanding of the real chemical reaction process in porous materials.