Experimental and Numerical Simulation Study of the Influence of Fe(C5H5)2-SiO2 Composite Dry Powders on Characteristics of Hydrogen/Methane/Air Explosion

In order to ensure the safety of methane/hydrogen, regular SiO2 powder was modified. Fe(C5H5)2/SiO2 composite dry powder (CDP) was selected as the explosion-suppression material. Explosion-suppression experiments and numerical simulations were adopted to investigate the inhibition effect of 0% (XH2 = 0%) and 20% (XH2 = 20%) hydrogen doping ratios. The flame structure, flame propagation speed, and maximum explosion pressure are depicted to compare the inhibition effect of different mass fractions (XFe(C5H5)2 = 0–6%). The results showed that CDP significantly reduced the flame propagation velocity and maximum explosion pressure of XH2 = 0%. The best effect was observed when 6% Fe(C5H5)2 was added, with the velocity reduced to 9.241 m/s. The maximum explosion pressure was reduced to 0.518 MPa, and the effect was relatively weak for XH2 = 20%, with the maximum pressure reduced to 0.525 MPa. In addition, the key radical production and temperature sensitivity showed that Fe(C5H5)2 altered the molar fractions of the major species and increased the consumption of •H, •O, and •OH. As the mass fraction of Fe(C5H5)2 increased, the steady-state concentrations of •H, •O, and •OH in the system showed a significant decreasing trend. This phenomenon originated from the two-step synergistic mechanism of Fe(C5H5)2 inhibiting radical generation and accelerating radical consumption. This study provides insight into the process of Fe(C5H5)2/SiO2 composite dry powder inhibition and renders theoretical guidance for the explosion protection of methane/hydrogen.