The lean blow-off (LBO) limits and structure of turbulent premixed flames were investigated with vaporized liquid fuels stabilized by a bluff-body burner. Ethanol, heptane, and two kerosenes were used. To facilitate comparisons to gaseous-fueled flames, results were also obtained from methane flames. The measured LBO limits indicate that, for this burner, the ethanol and heptane flames are more resilient to blow-off than the kerosene fuels. Furthermore, a correlation based on a Damköhler number ($Da$), which is proportional to the laminar flame speed, does not lead to the successful collapse of the different fuels, indicating that the $Da$ correlations based on laminar flame speed are not applicable. Average OH* chemiluminescence images of the ethanol and heptane flames are qualitatively similar to that from methane: the flame brushes of both exhibit an M shape when close to blow-off. In contrast, the distribution of OH* signal in the kerosene flames is primarily concentrated in regions further downstream of the bluff body. Ultimately, the results of this effort highlight the influence fuel type has on the LBO of bluff-body stabilized flames. Moreover, this work indicates the LBO behavior of flames produced with complex hydrocarbon fuels cannot be fully understood via high-temperature chemistry concepts such as the laminar flame speed.

用钝体燃烧器稳定的汽化液体燃料研究了稀薄吹气（LBO）极限和湍流预混火焰的结构。使用了乙醇，庚烷和两个煤油。为了便于与气体火焰进行比较，还从甲烷火焰中获得了结果。测得的LBO限值表明，对于这种燃烧器，乙醇和庚烷火焰比煤油燃料更有弹性。此外，基于Damköhler数（$d\mathrm{一种}$）（与层流火焰速度成比例）不会导致不同燃料的成功崩溃，这表明 $d\mathrm{一种}$基于层流火焰速度的相关性不适用。乙醇和庚烷火焰的平均OH *化学发光图像在质量上与甲烷相似：当接近吹扫时，两者的火焰刷均呈M形。相反，煤油火焰中OH *信号的分布主要集中在钝体下游的区域。最终，这项努力的结果突出了燃料类型对钝体稳定火焰的LBO的影响。此外，这项工作表明复杂的碳氢燃料产生的火焰的LBO行为无法通过层流火焰速度等高温化学概念完全理解。