This paper is part of a broader program aimed at investigating the effects of co-firing clean fuels such as ammonia or hydrogen with hydrocarbons. The focus is on soot formation as well as flame stability in turbulent mixed-mode combustion, which is highly relevant in practical combustors. Ammonia substitution for nitrogen results in reduced flame stability, and this is correlated to differences in flame speed and extinction strain rate. While it is known that the addition of ammonia suppresses soot, visual inspection of compositionally inhomogeneous flames of ethylene-ammonia indicates a reduction in ammonia's ability to suppress soot formation. Measurements of soot volume fraction and laser-induced fluorescence in selected UV and visible bands are made along the centreline in selected flames to test this hypothesis. Experimental results are then compared to simulations in laminar diffusion flames, stratified counterflow flames, and partially premixed flames. All results confirm the soot-inhibiting ability of ammonia. Increasing inhomogeneity, leading to higher centreline mixture fractions, enhances soot formation, and the level of enhancement is greater for flames with ammonia than without. Moreover, it is found that partial premixing is ultimately responsible for determining the amount of soot formed as opposed to stratification of fuel mixtures near the pilot.

本文是一项更广泛计划的一部分，该计划旨在调查氨或氢气等清洁燃料与碳氢化合物共燃的影响。重点是湍流混合模式燃烧中的烟灰形成和火焰稳定性，这与实际燃烧器高度相关。用氨代替氮会导致火焰稳定性降低，这与火焰速度和熄灭应变率的差异有关。虽然已知添加氨可抑制烟灰，但目视检查组成不均匀的乙烯-氨火焰表明氨抑制烟灰形成的能力降低。沿选定的 UV 和可见波段测量烟尘体积分数和激光诱导荧光选定火焰的中心线来检验这一假设。然后将实验结果与层流扩散火焰、分层逆流火焰和部分预混火焰中的模拟进行比较。所有结果都证实了氨的烟灰抑制能力。增加的不均匀性导致更高的中心线混合分数，增强了烟灰的形成，并且具有氨的火焰的增强水平比没有氨的火焰更大。此外，发现部分预混合最终决定了形成的烟灰量，而不是飞行员附近燃料混合物的分层。