Inhibition of Confined Hydrogen Explosion by Inert Gases

"This paper is aimed at revealing the inhibiting effects of He, Ar, N2 and CO2 on confined hydrogen explosion. The flame characteristics under thermo diffusive instability and hydrodynamic instability are analyzed using Lewis number and ratio of density ratio to flame thickness. The inhibiting effects of inert gas on confined hydrogen explosion are evaluated using maximum explosion pressure and maximum pressure rise rate. The inhibiting mechanism is obtained by revealing thermal diffusivity, maximum mole fraction and net reaction rate of active radicals. The results demonstrated that the strongest destabilization effect of hydrodynamic instability and thermodiffusive instability occurs when the inert gas is Ar and CO2, respectively. Taking maximum explosion pressure and maximum rate of pressure rise as an indicator, the effects of confined hydrogen explosion inhibition from strong to weak are CO2, N2, Ar and He. Laminar burning velocity, thermal diffusivity, maximum mole fraction and net reaction rate of active radicals, continues to decrease in the order of He, Ar, N2 and CO2. The elementary reactions of generating and consuming active radicals at the highest net reaction rate are mainly consisted of R1 (H+O2=OH+O), R2 (H2+O=OH+H), R3 (H2+OH=H2O+H) and R10 (HO2+H=2OH).