Studies on properties of laminar premixed oxygen-enriched NH3/H2/O2/N2 flames at elevated temperature and pressure

• Published in: Journal of the Energy Institute 2024-06, Vol.114, p.101645, Article 101645
• Main Authors: Ma, Pengcheng, Deng, Haoxin, Wen, Xiaoping, Song, Jun, Wang, Fahui, Chen, Guoyan
• Format: Article
• Language: English
• Subjects: Ammonia; Flame instability; Laminar burning velocity; Oxygen-enriched
• ISSN: 1743-9671
• DOI: 10.1016/j.joei.2024.101645

In this work, the effects of oxygen enrichment coefficient (Ω = 0.21 − 0.42) and initial temperature (Tu = 298 − 448 K) on the laminar burning properties of NH3/H2/O2/N2 flames are systematically investigated by using the spherical flame propagation method at equivalence ratios (Φ = 0.8 − 1.4) and initial pressure (Pu = 3 atm). LBV is analyzed by obtaining experimental data. In order to analyze flame instability, thermal diffusion and hydrodynamic instability are separated by linear stability theory. The thermal and chemical effects of oxygen enrichment on LBV and its effect on heat release rate are analyzed by numerical simulation. The results show that the laminar burning velocity (LBV) exhibits a positive correlation with both the oxygen enrichment coefficient and the initial temperature. The temperature index (α) exhibits a non-monotonic variation in response to the initial temperature of the NH3/H2/O2/N2 flame. Leeff is insensitive to temperature and positively correlated with the oxygen enrichment coefficient. The NH3/H2/O2/N2 flame is mainly affected by hydrodynamic instability when the oxygen enrichment coefficient is large. The peak NHRR scales positively with the oxygen enrichment coefficient. Oxygen enrichment helps to contribute to the overall net reaction rate. •The LBV of mixture flame with oxygen enrichment coefficient 0.21–0.42 was measured.•The effects of initial temperature on the LBV of the mixture flame were studied.•Thermal and chemical effects of oxygen enrichment were analyzed by adding virtual gas.•Diffusion thermal and hydrodynamic instability were separated by linear stability theory.