Direct numerical simulations of laboratory-scale NH3/air jet flames: Analysis of flame structure, flame stabilization and NO emission characteristics

被引：0
作者：
Tian, Tingquan [1 ]
Wang, Haiou [1 ]
Chen, Jacqueline H. [2 ]
Li, Zhongshan [3 ]
Alden, Marcus [3 ]
Luo, Kun [1 ]
Fan, Jianren [1 ]
机构：
[1] Zhejiang Univ, State Key Lab Cblean Energy Utilizat, Hangzhou 310027, Peoples R China
[2] Sandia Natl Labs, Combust Res Facil, Livermore, CA USA
[3] Lund Univ, Div Combust Phys, S-22100 Lund, Sweden
来源：
COMBUSTION AND FLAME | 2025年 / 274卷
关键词：
Direct numerical simulation; Ammonia combustion; Turbulent flame structure; Flame stabilization; NO formation characteristics; AMMONIA/AIR PREMIXED FLAMES; LAMINAR BURNING VELOCITY; TURBINE LIKE COMBUSTOR; STRAIN-RATE; AIR FLAMES; AUTOIGNITION; TEMPERATURE; CHEMISTRY; OXIDATION; MIXTURES;
D O I：
10.1016/j.combustflame.2025.114007
中图分类号：
O414.1 [热力学];
学科分类号：
摘要：
In the present study, three-dimensional direct numerical simulations (DNS) of experimental ammonia/air premixed jet flames with different turbulent intensities were performed. The DNS results were first compared to the measurements with good agreements. Based on the DNS data, the turbulent flame structure, stabilization mechanism and NO emission characteristics of the flames were investigated. It was found that the flame with higher turbulent intensity exhibits a higher degree of wrinkling and an increased flame surface area. In addition, turbulent eddies can enter into the reaction zone and disrupt the distributions of NH and temperature more strongly for the flame with higher turbulent intensity. It was shown that the heat release rate of the turbulent flame can be approximated by the results of strained laminar flames to some extent. Enhanced heat release rates were observed in the regions of negative curvature near the reactant side and in the regions of positive curvature near the product side, which is due to the local enhancement of radicals such as NH and NH2 that contribute significantly to the heat release. To understand the flame stabilization mechanism of the turbulent flames, corresponding one-dimensional unstrained and strained unsteady laminar flames were simulated. It was found that auto-ignition initially occurs and the reaction front transitions into a propagating front following the ignition process for both the unstrained and strained laminar flames. The ignition characteristics of the turbulent flames are largely consistent with those of the laminar flames. The study also revealed the NO formation characteristics. NO is consumed in the reaction zone and produced in the product side. The maximum NO mass fraction increases with increasing axial distance. Analysis of NO pathway suggests that this phenomenon is due to the enhanced NO production in the downstream regions, which is related to the accumulation of radicals such as OH, O and H. Novelty and significance This research reports the first direct numerical simulations of laboratory-scale ammonia/air turbulent premixed jet flames with varying turbulent intensities. The novelty of this research is that the flame structure, flame stabilization and NO emission characteristics of ammonia/air jet flames are explored using detailed DNS data, which are crucial for improved understanding of ammonia combustion. Furthermore, the present work provides high-fidelity DNS data of turbulent ammonia combustion for the development of combustion models.
引用
收藏
页数：15
相关论文
共 83 条
[1]  
Kobayashi H., Hayakawa A., Somarathne K.K.A., Okafor E.C., Science and technology of ammonia combustion, Proc. Combust. Inst., 37, 1, pp. 109-133, (2019)
[2]  
Elbaz A.M., Wang S., Guiberti T.F., Roberts W.L., Review on the recent advances on ammonia combustion from the fundamentals to the applications, Fuel Commun., 10, (2022)
[3]  
Dai L., Gersen S., Glarborg P., Levinsky H., Mokhov A., Experimental and numerical analysis of the autoignition behavior of NH3 and NH3/H2 mixtures at high pressure, Combust. Flame, 215, pp. 134-144, (2020)
[4]  
Dai L., Gersen S., Glarborg P., Mokhov A., Levinsky H., Autoignition studies of NH3/CH4 mixtures at high pressure, Combust. Flame, 218, pp. 19-26, (2020)
[5]  
Okafor E.C., Naito Y., Colson S., Ichikawa A., Kudo T., Hayakawa A., Kobayashi H., Experimental and numerical study of the laminar burning velocity of CH4–NH3–air premixed flames, Combust. Flame, 187, pp. 185-198, (2018)
[6]  
Okafor E.C., Naito Y., Colson S., Ichikawa A., Kudo T., Hayakawa A., Kobayashi H., Measurement and modelling of the laminar burning velocity of methane-ammonia-air flames at high pressures using a reduced reaction mechanism, Combust. Flame, 204, pp. 162-175, (2019)
[7]  
Rocha R.C., Zhong S., Xu L., Bai X.-S., Costa M., Cai X., Kim H., Brackmann C., Li Z., Alden M., Structure and laminar flame speed of an ammonia/methane/air premixed flame under varying pressure and equivalence ratio, Energy Fuels, 35, 9, pp. 7179-7192, (2021)
[8]  
Wang Z., Han X., He Y., Zhu R., Zhu Y., Zhou Z., Cen K., Experimental and kinetic study on the laminar burning velocities of NH3 mixing with CH3OH and C2H5OH in premixed flames, Combust. Flame, 229, (2021)
[9]  
Ichimura R., Hadi K., Hashimoto N., Hayakawa A., Kobayashi H., Fujita O., Extinction limits of an ammonia/air flame propagating in a turbulent field, Fuel, 246, pp. 178-186, (2019)
[10]  
Brackmann C., Zhou B., Li Z.S., Alden M., Strategies for quantitative planar laser-induced fluorescence of NH radicals in flames, Combust. Sci. Technol., 188, 4-5, pp. 529-541, (2016)
123456789