Effects of channel length on propagation behaviors of non-premixed H2-air flames in Y-shaped micro combustors |
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Affiliation: | 1. School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China;2. School of Energy and Power Engineering, Wuhan University of Technology, Wuhan, 430063, China;3. School of Mechanical & Mining Engineering, The University of Queensland, QLD, 4072, Australia;1. State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, PR China;2. Shenzhen Institute of Huazhong University of Science & Technology, Shenzhen 518057, PR China |
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Abstract: | In the present study, dynamics of non-premixed hydrogen-air flames in two Y-shaped cylindrical micro combustors of different horizontal channel lengths (L = 100 and 200 mm) were experimentally compared. The inner diameters of the micro-combustors are 2 mm. Unburned mixture was ignited by heating the near-exit wall with a butane torch. The results show that six and three flame propagation modes in the 200-mm and 100-mm micro-combustors were observed, respectively. Moreover, it is found that the flame oscillation duration is much longer with a larger noise intensity in the 200-mm micro-combustor. As a result, the mean propagation speed under L = 100 mm is much larger. In addition, the edge flame is longer on the lean side under L = 100 mm and almost identical on the rich side for the two combustors. Furthermore, the luminosity of edge flame in the 100-mm micro-combustor is much brighter. Numerical analysis reveals that the deflection of propagating flame in the Y-shaped micro-combustor is determined by the stoichiometric line. In summary, the short combustor has a smaller heat loss ratio and a stronger flame-wall thermal coupling, which can enhance the combustion intensity and increase the flame propagation speed. |
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Keywords: | Micro-combustor Noise emission Flame oscillation Edge flame Flame propagation speed |
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