Studies of Blowout of Turbulent Diffusion Flames

CTS-9905786本文对喷吹火焰的机理和喷吹附近反应区的形态进行了实验研究。研究了大尺度结构动力学对井喷附近火焰的影响。用同步粒子图像测速仪(PIV)和双脉冲平面激光诱导荧光(PLIF)测量了火焰区相对于燃料流动的传播速率。CH自由基的双脉冲PLIF图像提供了火焰前锋运动的信息，而PIV提供了燃烧区域内燃料速度的信息。利用CH-PLIF对爆燃附近燃烧区前缘的结构进行了评估。这种可视化是针对各种流动条件和下游位置进行的。对甲烷、乙烯和丙烷等多种燃料，评估了空气同流速度对火焰熄灭的影响。对近场火焰和远场火焰的预混程度进行了对比研究，重点研究了火焰的扩散稳定机理和火焰向爆燃的过渡过程。

CTS-9905786AbstractThis is an experimental investigation of the mechanisms of jet flame blowout and of the morphology of the reaction zone near blowout. The effects of the dynamics of large-scale structures on flames near blowout is examined. Measurements of the propagation rate of the flame zone relative to the fuel flow are made using simultaneous particle image velocimetry (PIV) and double-pulsed planar laser-induced fluorescence (PLIF). The double-pulsed PLIF images of the CH radical provide information on the motion of the flamefront, while PIV provides information on the fuel velocity in the combustion zone. Assessment of structures at the leading edge of the combustion zone near blowout is made using CH-PLIF. Such visualizations are performed for a variety of flow conditions and downstream positions. The effect of the air coflow velocity on flame blowout is assessed for a variety of fuels such as methane, ethylene, and propane. Further studies are performed to contrast premixedness in the flowfields in near-field lifted flames to far-field flames with an emphasis on the mechanism of lifted diffusion flame stabilization and the transition to blowout.