Effects of ambient temperature on flame propagation characteristics of methanol spray-hydrogen explosions

Abstract

Methanol-hydrogen fuel forms explosive spray droplet clouds during storage and transport. Therefore, understanding the propagation characteristics of spray flames is crucial for safe application. This study systematically investigates the impact of ambient temperature, methanol concentration, and hydrogen addition on flame propagation characteristics and reaction kinetics. A spray combustion model was developed and validated against experimental data. The results indicated that hydrogen addition played a dominant role in the variations of flame structure and explosion intensity. Compared with pure methanol spray combustion, the flame with 10.0 % hydrogen addition exhibited a smooth and symmetric structure, resembling that of a premixed gas‑phase flame. Its average propagation speed reached 3.04 times that of the pure methanol case, and the explosion index increased by 223.38 %. Ambient temperature had a non‑monotonic effect on flame propagation. At excessively high temperatures, the evaporative cooling of methanol suppressed combustion. Chemical kinetic analysis showed that the H-abstraction pathways R84 and R85 dominated methanol consumption, while R1 and R30 had the strongest inhibitory effect on flame temperature. This paper clarifies the combined effects of ambient temperature and hydrogen addition on methanol spray explosions, providing a theoretical basis for the safe storage and risk management of blended fuels.