In this study, the flame dynamics of swirl stabilized lean premixed combustion is investigated for kerosene and natural gas operation. A natural gas swirl burner is retrofitted with a twin-fluid nozzle to allow performing all experiments with the identical burner hardware. The mixture preparation complexity is stepwise increased from perfectly premixed natural gas to technically premixed natural gas and lastly technically premixed kerosene combustion. Flame transfer functions (FTFs) for the three configurations are presented and compared with each other. This approach allows to experimentally decompose the FTF and isolate the contributions of equivalence ratio fluctuations and droplet dynamics. Furthermore, FTF data for a systematic variation of equivalence ratio and air mass flow in kerosene operation is presented and the impact of spray quality and convective delay time on the FTF is discussed. For all operation points, stationary flame images are provided and evaluated as basis for the FTF interpretation. Additionally, NO[Math Processing Error]${}_{\mathrm{x}}$${}_{\mathrm{x}}$ emissions are measured in order to determine the degree of premixing in kerosene operation. Through a systematic FTF comparison, it was found that the frequency range in which droplets react to acoustic forcing can be read from the FTF phase. The spray quality was found to have a significant impact on the FTF whereas a change in the convective delay time does not affect the FTF.

在这项研究中，研究了煤油和天然气运行的涡流稳定稀薄预混燃烧的火焰动力学。天然气旋流燃烧器改装了双流体喷嘴，以允许使用相同的燃烧器硬件进行所有实验。混合物制备的复杂性逐步增加，从完全预混天然气到技术预混天然气，最后是技术预混煤油燃烧。介绍了三种配置的火焰传递函数 (FTF) 并相互比较。这种方法允许通过实验分解 FTF 并隔离当量比波动和液滴动力学的贡献。此外，给出了煤油操作中当量比和空气质量流量系统变化的 FTF 数据，并讨论了喷雾质量和对流延迟时间对 FTF 的影响。对于所有操作点，提供静止火焰图像并作为 FTF 解释的基础进行评估。此外，没有[数学处理错误]${}_{\mathrm{X}}$${}_{\mathrm{x}}$测量排放物以确定煤油操作中的预混程度。通过系统的FTF比较，发现液滴对声学强迫反应的频率范围可以从FTF相中读出。发现喷雾质量对 FTF 有显着影响，而对流延迟时间的变化不影响 FTF。