Investigation of the effects of N₂ and CO₂ on the overpressure hazards, flame behaviors and reaction kinetics of LPG/air explosions

To research the influence of inert gases on the explosion behaviors of LPG/air mixtures, LPG explosion tests suppressed by CO2 and N-2 were conducted in a spherical chamber and the chemical reaction kinetic properties were analyzed. The results show that CO2 has a better inhibitory effect than N-2, especially when the added amount is small. With the increasing volume fraction of inert gases, the LPG explosion flame propagation speed continuously decreases, and the phenomenon of flame uplift and wrinkling deformation occurs. The explosion pressure of LPG/CO2(N-2)/air mixture and the average flame propagation speed in the initial stage follow an exponential function with an offset. The laminar flame structure of 4% LPG is similar to its mixtures with N-2 and CO2. After adding inert gases, the maximum temperature of the LPG laminar flame decreases significantly, and the flame thickness increases. The key elementary reactions affecting the N-2(CO2)/LPG/air explosions are given. The research results have important implications for suppression of LPG explosions.