Effect of N₂ and CO₂ dilution on syngas/air deflagration characteristics in narrow gap disk burner

ABSTRACT

This study explored the typical features of flame from syngas/air premixed flame in a narrow gap disk burner based on diluted N₂ and CO₂. Four concentrations (i.e. 10%, 20%, 30%, and 40%) of CO₂ and five concentrations (i.e. 10%, 20%, 30%, 40%, and 50%) of N₂ were adopted in this study. The experiment was conducted in a narrow gap disk burner with a clearance of 2 mm. The results showed that the addition of N₂ and CO₂ significantly reduced the brightness of flame, the flame propagation velocity, and the pressure resulting from the explosion. When the CO₂ concentration reached 40%, the maximum pressure was reduced to 60.78 kPa, which was 41.5% lower than that without diluent. When the N₂ concentration was increased to 50%, the maximum pressure was reduced to 67.01 kPa, but at this point, the inhibition effect on the maximum pressure was not as good as 40% of CO₂. Additionally, the dilution effect of CO₂ was more obvious than of N₂. An analysis on the dilution mechanism found that reduced moles of critical radicals H, O, and OH were an important reason for the inhibition effect. However, with the increase of N₂ and CO₂ concentrations, the unstable flame propagation behavior in a later stage was not inhibited, but enhanced. The unstable propagation behavior was related to the flow field disturbance caused by heat loss.

KEYWORDS:

• Dilution effect
• narrow gap disk burner
• syngas/air
• instability propagation, flame propagation

Acknowledgements

This paper is supported by the National Natural Science Foundation of China (No. 51774115); Henan Provincial Science and Technology Research Project (No. 222102320105).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [51774115]; Henan Provincial Science and Technology Research Project [222102320105]