Phase change materials as hydrogen explosion suppressants: An experimental and kinetic investigation

Abstract

To investigate the potential application of phase change materials as H2 explosion suppressants, in the present work, the inhibition effect of Na2HPO4·12H2O, K2HPO4·3H2O, and Na2CO3·10H2O on H2 explosion were experimentally studied. The corresponding explosion suppression mechanism was calculated by using a comprehensive combustion model. Results showed that the selected phase change materials inhibited the H2 explosion, and Na2CO3·10H2O has the most significant effect for fuel-lean H2-air mixtures when 12 g was added. Of which the maximum explosion pressure (Pmax) and maximum rate of pressure rise (dp/dt)max were reduced by 26.6 % and 28.1 %, and maximum pressure increase time (tb) and peak pressure time(tc) were increased by 112.2 % and 120.3 %. The inhibition mechanism of Na2CO3·10H2O on H2 was revealed by numerical simulation. The adiabatic flame temperature (AFT) and laminar burning velocity (LBV) of H2-air mixture decrease with increasing hydrated salt addition, the free radicals H, O and OH have a decisive influence on the explosion process during which H decreases by 86.4 % at most. The chain initial reaction O + H2 ⇌ H + OH and the sodium-containing primitive reaction NaO + H + M ⇌ NaOH + M have the most significant influence on the combustion processes. The results of present work give a theoretical foundation for application the phase change materials in H2 explosion safety industry.