Initial temperature effect on NaHCO3-inhibited hydrogen/methane/ air flames

To investigate the effect of initial temperature on NaHCO3-inhibited stoichiometric hydrogen/methane/air (SHMA) flames, experiments were conducted in a 36 L spherical vessel to evaluate the relationship between the initial temperature (T0 = 298-398 K) and maximum explosion pressure (Pmax) of the inhibited SHMA flames under a fixed hydrogen fraction of 25%. The results indicated that the inhibitory effect of NaHCO3 decreased with increasing initial temperature. The overpressure drop ratios were 26.82% and 15.74% for initial temperatures of 298 and 398 K at 250 g/m3, respectively. The impact of T 0 on the endothermic effect of NaHCO3 was quantitatively assessed via a more detailed thermal decomposition equilibrium equation for NaHCO3. After the addition of 250 g/m3 NaHCO3, the endothermic heat at 298 and 398 K reached 13.35 and 9.97 kJ/m3, respectively. A simplified kinetic model incorporating both NaHCO3 and NaOH components was used to evaluate the laminar burning velocity (SL). A strong correlation was established between the S L and the experimental variables (T0 and C ). In addition, T 0 , C , methane and hydrogen mole fractions were used as inputs for neural network predictions of P max and S L for the SHMA. These findings provide a crucial research foundation for the safe transportation and explosion suppression of SHMA or other similar gases in industrial applications.