等离子体激励下NH₃/CH₄射流火焰特性的实验研究

Experimental Study on the Characteristics of NH₃/CH₄ Jet Flame Excited by Plasma

摘要: 为应对氨燃料燃烧过程中存在的效率低和火焰不稳定等挑战，本文提出了一种耦合等离子体的氨掺混燃烧方案。通过掺混高反应活性燃料甲烷提升氨火焰稳定性，辅助等离子体助燃技术以进一步提高氨掺混燃烧效率。首先，搭建氨/甲烷燃烧实验系统，设计介质阻挡放电(DBD)等离子体发生器。其次，采集火焰动态实验图像及等离子体电参数，并通过图像处理技术定量分析火焰特性，探讨等离子体激励下氨/甲烷共燃的火焰形态及燃烧特性。实验结果表明，DBD等离子体的引入显著降低火焰高度并增加火焰宽度，其热效应与化学活性加速了燃烧反应进程；外加电压的提升增强了等离子体电离强度，促进活性粒子生成，扩大火焰扩散范围；掺氨比的增加使得火焰传播速度降低，火焰锋面缩短，导致火焰高度持续下降，而火焰宽度则呈现整体减少的趋势。

Abstract: To cope with the challenges of low efficiency and flame instability in the combustion process of ammonia fuel, this paper proposes an ammonia blending combustion scheme coupled with plasma. The stability of ammonia flame is improved by mixing high reactivity fuel methane, and the plasma-assisted combustion technology is used to further improve the combustion efficiency of ammonia blending. Firstly, an ammonia/methane combustion experimental system was built, and a dielectric barrier discharge (DBD) plasma generator was designed. Secondly, the flame dynamic experimental images and plasma electrical parameters were collected, and the flame characteristics were quantitatively analyzed by image processing technology. The flame morphology and combustion characteristics of ammonia/methane co-combustion under plasma excitation were discussed. The experimental results show that the introduction of DBD plasma significantly reduces the flame height and increases the flame width, and its thermal effect and chemical activity accelerates the combustion reaction process. The increase of the applied voltage enhances the ionization intensity of the plasma, promotes the generation of active particles, and expands the flame diffusion range. The increase of ammonia ratio reduces the flame propagation speed and shortens the flame front, resulting in a continuous decrease in flame height, while the flame width shows an overall decreasing trend.