Analysis of the effect mechanism of water and CH4 concentration on gas explosion in confined space

In order to study the effect of water and CH₄ concentration on gas explosion, a 20L spherical explosive device was used to carry out a water-containing gas explosion experiment, and the explosion simulation was carried out with CHEMKIN-PRO, the mechanism of water on gas explosion was analyzed from the perspective of free radicals and energy. The results showed that the upper limit of gas explosion, maximum explosion pressure and temperature decreased significantly with the increase of water content. The higher the concentration of CH₄, the more obvious the inhibitory effect of water on gas explosion pressure, and the optimal explosion concentration of CH₄ decreased with the increase of water content. As the water content and CH₄ concentration increase, the residual CH₄ content increases after the explosion, the O₂ content decreases, and the CO content produced increases. When the CH₄ concentration is lower than the optimal concentration, water promotes the formation of CO₂ to a certain extent; when the CH₄ concentration is higher than the optimal explosive concentration, the CO₂ content decreases with the increase of water content. Overall, water inhibits methane explosion, the addition of water on the one hand reduces the concentration of active free radicals H, O, OH, on the other hand, it interferes with the generation of gas explosion energy and consumes the kinetic energy of the gas explosion flame shock wave through heat absorption, thus inhibiting the intensity of gas explosion.