水蒸气/二氧化碳/氮气工质下甲烷纯氧微混燃烧特性

In response to the future development needs for efficient，advanced，zero-emission gas turbines，we established a system for generating superheated water vapor (200 ℃) and designed an axial-tangential micro-mixing swirl nozzle to conduct experiments on pure oxygen combustion under conditions of water vapor dilution in this study. The results showed that as the flow rate of water vapor dilution increased， the concentration of oxygen decreased， leading to four distinct flame structure process-es: attached to the inside of the nozzle， attached to the outlet of the nozzle， flame lifting， and blowout occurrence. Moreover， we observed an increase in flame resistance against blowout with high-er equivalent ratios. Subsequently，we investigated flame stability with H₂O(g)/CO₂/N₂ dilution at different equivalent ratios and discovered that H₂O(g) dilution exhibited better stability compared to CO₂ dilution. Furthermore，we measured flame temperatures under three diluted gases and discovered that water vapor dilution yielded the highest temperature. Finally，through PIV analysis of the cold flow field within a glass tube， we identified a prominent reflow area on its exterior， and the distribution of axial velocity demonstrated a minimum point 20 mm above the nozzle exit， which enhanced flame stability and improved resistance against blow-out.