The effect of hydrogen ( $$\mathrm {H}_{\mathrm {2}}$$ ) enrichment on the flame-holding characteristics of two natural gas jet flames in crossflow is investigated here, experimentally. The flame and flowfield measurements are analyzed using simultaneously acquired high-speed (10 kHz) stereoscopic particle image velocimetry, planar laser-induced fluorescence of the hydroxyl radical, and OH* chemiluminescence. The flames, enriched with 20% and 40% $$\mathrm {H}_{\mathrm {2}}$$ , by volume, are studied at conditions typical of the mixing duct of a modern gas turbine engine; specifically in confinement, at 10 bars, and with a crossflow preheat of 530 K. Consistent with previous findings, the 40% $$\mathrm {H}_{\mathrm {2}}$$ flame was found to be stabilized on the windward and leeward side of the jet, while the 20% $$\mathrm {H}_{\mathrm {2}}$$ flame was stabilized only on the leeward side. Analysis of mean and instantaneous velocity fields showed no major differences in the trajectories and principal compressive strain fields of the two flames. The presence of the windward stabilized flame in the 40% $$\mathrm {H}_{\mathrm {2}}$$ case was, however, found to decrease the centerline velocity decay and greatly reduce or eliminate large scale vortices along the windward shear layer. The difference in the flame-holding here was attributed to the difference in the extinction strain rate from the addition of hydrogen, which would impact the local and global extinction of the flame along the high shear windward region of the flame.

中文翻译：

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富氢对高温高压横流天然气射流火焰持焰的影响

这里通过实验研究了氢气 ( $$\mathrm {H}_{\mathrm {2}}$$ ) 富集对横流中两个天然气喷射火焰的火焰保持特性的影响。使用同时获得的高速 (10 kHz) 立体粒子图像测速法、羟基自由基的平面激光诱导荧光和 OH* 化学发光分析火焰和流场测量值。在现代燃气涡轮发动机的混合管道的典型条件下研究了按体积计分别含有 20% 和 40% $$\mathrm {H}_{\mathrm {2}}$$ 的火焰；特别是在限制条件下，10 巴，交叉流预热为 530 K。与之前的发现一致，发现 40% $$\mathrm {H}_{\mathrm {2}}$$ 火焰稳定在喷气机的迎风面和背风面，而 20% $$\mathrm {H}_{\mathrm {2}}$$ 火焰仅在背风侧稳定。平均和瞬时速度场的分析表明，两种火焰的轨迹和主压应变场没有重大差异。然而，在 40% $$\mathrm {H}_{\mathrm {2}}$$ 情况下，迎风稳定火焰的存在被发现减少了中心线速度衰减并大大减少或消除了沿迎风切变层。此处火焰保持的差异归因于添加氢气的消光应变率的差异，这将影响火焰沿高剪切迎风区域的局部和全局熄灭。平均和瞬时速度场的分析表明，两种火焰的轨迹和主压应变场没有重大差异。然而，在 40% $$\mathrm {H}_{\mathrm {2}}$$ 情况下，迎风稳定火焰的存在被发现减少了中心线速度衰减并大大减少或消除了沿迎风切变层。此处火焰保持的差异归因于添加氢气的消光应变率的差异，这将影响火焰沿高剪切迎风区域的局部和全局熄灭。平均和瞬时速度场的分析表明，两种火焰的轨迹和主压应变场没有重大差异。然而，在 40% $$\mathrm {H}_{\mathrm {2}}$$ 情况下，迎风稳定火焰的存在被发现减少了中心线速度衰减并大大减少或消除了沿迎风切变层。此处火焰保持的差异归因于添加氢气的消光应变率的差异，这将影响火焰沿高剪切迎风区域的局部和全局熄灭。发现减少中心线速度衰减并大大减少或消除沿迎风切变层的大尺度涡流。此处火焰保持的差异归因于添加氢气的消光应变率的差异，这将影响火焰沿高剪切迎风区域的局部和全局消光。发现减少中心线速度衰减并大大减少或消除沿迎风切变层的大规模涡流。此处火焰保持的差异归因于添加氢气的消光应变率的差异，这将影响火焰沿高剪切迎风区域的局部和全局消光。