The flame stabilization behavior of a premixed ethylene–air jet injected normal to a hot vitiated crossflow (JICF) was studied experimentally using simultaneous hydroxyl (OH) planar laser induced fluorescence (PLIF), formaldehyde (CH₂O) PLIF, and particle image velocimetry (PIV). Pixel-by-pixel multiplication of OH and CH₂O fluorescence signals was conducted to estimate the reacting JICF flame front. The simultaneous PLIF-PIV measurements allowed for an in-depth study of the interaction between the flame and the flowfield. The flame structure was divided into two branches, a windward and leeward flame branch. The unsteady windward flame exhibited both attached and lifted flame behavior, while the leeward flame branch remained consistently attached at the jet exit. In some cases, formaldehyde signal was observed upstream of the windward flame base, suggesting the build-up of a radical pool due to mixing between the jet reactants and hot crossflow. Both flame branches were anchored in the jet shear layer, but with increasing distance from the jet exit the flames moved inside the shear layers. Small scale vortices caused local wrinkling of the flame front. The windward flame was observed to wrap around the large-scale vortices that formed along the jet shear layer. The large-scale structures distorted the flame front but the associated strain-rate was typically lower than that imparted by the small-scale structures. The leeward flame edge aligned with regions of high principal extensive strain-rate and high dilatation. On the other hand, the windward flame edge was located in regions where principal extensive and principal compressive strain rate magnitudes were high and dilatation was low. The results suggest that auto-ignition is the dominant flame stabilization mechanism for the unsteady windward flame and premixed flame propagation is the more dominant stabilization mechanism for the leeward flame branch.

使用同时羟基（OH）平面激光诱导荧光（PLIF），甲醛（CH ₂ O）PLIF和粒子图像测速仪，通过实验研究了垂直于热风流（JICF）的预混乙烯-空气射流的火焰稳定行为。（PIV）。OH和CH _2的逐像素相乘进行O荧光信号以估计反应的JICF火焰前锋。同时进行PLIF-PIV测量可以深入研究火焰与流场之间的相互作用。火焰结构分为两个分支，上风和下风火焰分支。不稳定的迎风火焰同时表现出附着和抬升的火焰行为，而下风向火焰分支在喷射出口处始终保持附着。在某些情况下，在迎风火焰底座的上游观察到甲醛信号，这表明由于喷射反应物和热横流之间的混合，自由基池的建立。两个火焰分支都固定在射流剪切层中，但是随着距射流出口的距离增加，火焰在剪切层内部移动。小规模的旋涡导致火焰前缘局部起皱。观察到迎风火焰包裹了沿射流剪切层形成的大规模旋涡。大型结构使火焰前沿变形，但相关的应变率通常低于小型结构所赋予的应变率。下风向的火焰边缘与高主要广泛应变率和高膨胀区域对齐。另一方面，迎风火焰边缘位于主要扩展和主要压缩应变率幅度大而扩张低的区域。结果表明，自燃是不稳定风向火焰的主要稳定机制，而预混火焰的传播是风向火焰分支的主要稳定机制。