Flame propagation mechanism of methanol fuel spray explosion in a square closed vessel

Abstract

Methanol, as an important chemical raw material and clean energy source, easily forms explosive droplet clouds during its production, processing, and usage. Therefore, understanding the evolution and propagation mechanisms of methanol spray explosion flames is crucial for its widespread use and the design of safety measures. This paper studies the flame propagation behavior of methanol spray explosions using a 16.2-L visualized enclosed vessel. The results indicate that the flame structure of methanol spray explosions is similar to that of premixed gas explosions but significantly differs from traditional fossil fuels. It demonstrates homogeneous combustion characteristics primarily governed by the kinetics-controlled regime. As the methanol spray concentration increases, both the maximum flame propagation speed and the maximum explosion pressure initially increase and then decrease, reaching their peak at a concentration of 224.68 g/m3, with values of 9.96 m/s and 0.72 MPa, respectively. The heat losses during combustion exhibit a trend opposite to that of explosion pressure. Numerical simulation results indicate that the concentrations of key radicals such as O, H, and OH vary significantly between lean and rich combustion states. The increase in H radical concentration enhances the elementary reactions that suppress flame temperature and promotes chain-terminating reactions.