Blowing off multiple flames by air vortex ring: flame stretch and gravity effects

作者：Sainan Quan, Caiyi Xiong, Feng Zhu, Xinyan Huang, Shuangfeng Wang · 发表于：Applications in Energy and Combustion Science · 年份：2026 · DOI：10.1016/j.jaecs.2026.100547 · 研究领域：Fire dynamics and safety research、Combustion and flame dynamics、Combustion and Detonation Processes

Multi-flame sources represent one of the most challenging fire scenarios to extinguish, and the intense injection of suppression agent may cause secondary ignition. This work investigates the performance of air vortex rings in extinguishing a line of up to 7 candle flames (38 W each in normal gravity) and the effects of buoyancy-driven disturbances. To decouple the buoyancy effect, microgravity experiments are conducted in a 3.6-s drop tower, and a piston-tube apparatus is developed to generate stable vortex rings with energies up to 1 mJ for extinguishing multiple candle flames. Results show an 11% relative increase in vortex extinguishing capacity in microgravity, based on which the mechanism for vortex-induced multiple flame extinction is revealed using flame stretch rate. The rotation of the vortex ring contributes strongly to flame stretch and entrainment, while the translation laterally blows the flame away. In microgravity, the vortex ring requires a lower stretch rate to extinguish the flame than in normal gravity, and the elimination of buoyancy disturbances allows it to maintain a high rotational kinetic energy. In multi-flame scenarios, the vortex ring effectively utilizes its energy, achieving up to 3 times the efficiency compared to extinguishing a single flame. This efficiency can be further improved in microgravity or by optimizing the kinetic energy structure of the vortex ring. This work provides a fundamental understanding of vortex-induced extinction, offer...