The shear layer is a region between the internal and external recirculating zone of the flame, which is critical for combustion stabilization and emission. This study experimentally studied the effects of oxyfuel (CO₂/O₂) shear layer injections on combustion dynamics and pollutant emissions of a model gas turbine combustor. To evaluate the damping performances of ‘Oxy’ CO₂/O₂ shear layer jets on unsteady combustion and pollutant formation processes, four variables of the CO₂/O₂ shear layer injection system are studied—the flow rate, the inner diameter, the injection angle and the oxygen ratio. Experimental results show that thermoacoustic instability and NO_x emissions can be suppressed with the ‘Oxy’ CO₂/O₂ shear layer injection method. The minimum inner diameter cases could achieve better control effectiveness of 80%, with the sound pressure amplitude drops from 27 to 5.4 Pa. The maximum inner diameter case could achieve better control effectiveness of 59.2%, with the concentration of NO_x emissions drops from 25 to 10.2 ppm. Flame oscillation modes experienced shifting and switching under different shear layer angles and oxygen ratios. There exist extreme points that can be selected for a better control effect. The CO₂/O₂ shear layer injection splits the inner and outer recirculation zones of the flame. As the oxygen ratio of CO₂/O₂ varied from 36% to 46%, a flame flapping phenomenon emerged. The ‘Oxy’ CO₂/O₂ shear layer injection method could eliminate combustion instability and NO_x emissions at a relatively lower cost and complexity, which will promote the development of high-performance burners.

中文翻译：

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用环形氧燃料射流进入火焰剪切层区域减轻燃烧不稳定性和 NOx 排放

剪切层是火焰内部和外部再循环区之间的区域，对燃烧稳定和排放至关重要。本研究通过实验研究了氧燃料 (CO ₂ /O ₂ ) 剪切层喷射对模型燃气轮机燃烧器的燃烧动力学和污染物排放的影响。为了评估“Oxy”CO ₂ /O ₂剪切层射流对不稳定燃烧和污染物形成过程的阻尼性能，研究了CO ₂ /O ₂剪切层喷射系统的四个变量——流速、内径、喷射角和氧比。实验结果表明热声不稳定性和 NO _x'Oxy' CO ₂ /O ₂剪切层注入方法可以抑制排放。的最小内径的情况下可取得较好的控制效力的80％，与声压振幅下降27至5.4帕。最大内径的情况下可以达到59.2％更好的控制效果，与NO的浓度_X的排放量从25下降到 10.2 ppm。火焰振荡模式在不同的剪切层角度和氧比下经历了移动和切换。存在可以选择的极值点以获得更好的控制效果。CO ₂ /O ₂剪切层喷射将火焰的内部和外部再循环区分开。作为CO ₂ /O的氧比₂从 36% 到 46% 不等，出现了火焰扑动现象。'Oxy'CO ₂ /O ₂剪切层喷射方法可以以相对较低的成本和复杂性消除燃烧不稳定性和NO _x排放，这将促进高性能燃烧器的发展。