TY - JOUR
T1 - Experimental study of flame evolution, frequency and oscillation characteristics of steam diluted micro-mixing hydrogen flame
AU - Cao, Zhen
AU - Lyu, Yajin
AU - Peng, Jiangbo
AU - Qiu, Penghua
AU - Liu, Li
AU - Yang, Chaobo
AU - Yu, Yang
AU - Chang, Guang
AU - Yan, Biao
AU - Sun, Shaozeng
AU - Yu, Xin
N1 - KAUST Repository Item: Exported on 2021-06-09
Acknowledgements: Thanks to the reviewers and editor for manuscript improvements. This research was funded by the National Natural Science Foundation of China (Grant Nos. 51536002, 51976048, and 61405048).
PY - 2021/5/21
Y1 - 2021/5/21
N2 - Effects of steam dilution on flame evolution, frequency and oscillation characteristics were investigated using an optically accessible micro-mixing combustor under the lean operating condition (equivalence ratio 0.4 to 0.9). The flame profile was visualized by 5 kHz OH planar laser-induced fluorescence (PLIF), meanwhile the structural zoning analysis, frequency spectrum and dynamic mode decomposition (DMD) methods were used to investigate flame instability. The effects on frequency-shift and temporal-spatial heat-release distribution characteristics were demonstrated. Results indicated that heat-release frequency got blue-shift with the increase of hydrogen equivalence ratio while flame length gradually extended, though the second harmonic frequency only occurred in the flame arm zone. The steam content influenced the heat-release obviously, and the obvious periodic oscillation existed in the dilution ratio of 25%. Furthermore, the increasing or decreasing steam content will make the OH radical concentration and distribution change significantly, meanwhile the intensity and location of oscillation zone were also be influenced. The mode decomposition analysis revealed the growth of oscillation zone was closely related to the flame arm zone (FAZ) and experienced the transition to the flame tail zone (FTZ) with the increase of equivalence ratio.
AB - Effects of steam dilution on flame evolution, frequency and oscillation characteristics were investigated using an optically accessible micro-mixing combustor under the lean operating condition (equivalence ratio 0.4 to 0.9). The flame profile was visualized by 5 kHz OH planar laser-induced fluorescence (PLIF), meanwhile the structural zoning analysis, frequency spectrum and dynamic mode decomposition (DMD) methods were used to investigate flame instability. The effects on frequency-shift and temporal-spatial heat-release distribution characteristics were demonstrated. Results indicated that heat-release frequency got blue-shift with the increase of hydrogen equivalence ratio while flame length gradually extended, though the second harmonic frequency only occurred in the flame arm zone. The steam content influenced the heat-release obviously, and the obvious periodic oscillation existed in the dilution ratio of 25%. Furthermore, the increasing or decreasing steam content will make the OH radical concentration and distribution change significantly, meanwhile the intensity and location of oscillation zone were also be influenced. The mode decomposition analysis revealed the growth of oscillation zone was closely related to the flame arm zone (FAZ) and experienced the transition to the flame tail zone (FTZ) with the increase of equivalence ratio.
UR - http://hdl.handle.net/10754/669444
UR - https://linkinghub.elsevier.com/retrieve/pii/S0016236121009571
UR - http://www.scopus.com/inward/record.url?scp=85107059661&partnerID=8YFLogxK
U2 - 10.1016/j.fuel.2021.121078
DO - 10.1016/j.fuel.2021.121078
M3 - Article
SN - 0016-2361
VL - 301
SP - 121078
JO - Fuel
JF - Fuel
ER -