Characteristic Behavior of Methane/Hydrogen Premixed Flame in Ultrafine Water Mist with Potassium Additives

ABSTRACT

In order to improve the suppression effect of methane/hydrogen deflagration, it is essential to understand the effects of the addition of ultrafine water mist on their explosion characteristics. An experimental study on the flame propagation behavior of methane/hydrogen premix flames influenced by ultrafine water mist with K₂C₂O₄·H₂O additives was carried out in a 10 mm × 10 mm × 100 mm tube. The results confirmed that potassium additives can improve the inhibition effect of ultrafine water mist, but the inhibition effect shows an inverted “V” shape with the increase of mass concentration. Inhibitory effects from high to low are: 15% K₂C₂O₄·H₂O >3% K₂C₂O₄·H₂O >0% K₂C₂O₄·H₂O >9% K₂C₂O₄·H₂O The addition of ultrafine water mist has both an inhibiting and an enhancing effect on flame propagation. Physical inhibition includes energy absorption by droplet fragmentation, heat absorption by evaporation and dilution of combustible gas components with CO₂ to reduce the rate of combustion. Chemical inhibition occurs when small molecule alkali metals reduce the concentration of free radicals such as •O, •H and •OH. In addition, the unevaporated droplets and CO from pyrolysis have an enhanced effect on deflagration.

KEYWORDS:

• Methane/Hydrogen premixed flame
• ultrafine water mist
• potassium additives
• inhibition-enhancement effects
• cellular structure

Acknowledgements

This work was supported by the National Natural Science Foundation of China (NSFC 52274177, 51704054), Natural Science Foundation of Chongqing Scientific and Technological (CSTB2023NSCQ-MSX0862).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [NSFC 52274177]; Natural Science Foundation of Chongqing Scientific and Technological [CSTB2023NSCQ-MSX0862].