Ammonia/methane fuel blends have gathered interest as a promising solution for the development of a low-carbon energy system. In that pursuit, this work focused on the effects of turbulent intensity (u′ = 1.3–2.6 m/s), ammonia contents (XNH3 = 0.0–1.0), and equivalence ratios (ϕ = 0.5–0.9) on the flame structure and NO emissions of bluff-body swirl-stabilized premixed flames of ammonia/methane/air as well as their links to hydroxyl planar laser-induced fluorescence (OH-PLIF) intensity. Three swirling flame shapes are distinguished, which are jointly determined by the ammonia content and equivalence ratio. The normalized OH-PLIF intensity (Iaverage/SL) of all XNH3, u′, and ϕ can be collapsed well onto one unified correlation as a function of the normalized turbulent intensity u′/SL. The flame surface density (FSD, marked as Σ) of confined swirling flames was rarely reported before, and the FSD in a V shape increases obviously when transiting to a M shape as the ammonia content reduces. The turbulent flame area ratio (AT/AL) derived from the FSD is increasing as u′/SL increases; however, it decreases first and then increases as ϕ increases. Then, a new description of the link between NO, OH, and XNH3 was provided, which improves the correlation performance more than the previous studies only considering the link between NO and OH.
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Chemical Engineering(all)
- Fuel Technology