在本論文研究中，以暫態數值模擬搭配實驗驗證，針對甲烷火焰在內環通入燃料，外環為氧化劑同軸流燃燒器中進行暫態數值分析。燃料選用甲烷，氧化劑則是氧氣與二氧化碳依照特定比例混合，以10%為間隔，使二氧化碳在氧化劑流中佔比從40%到60%進行變化。數值模擬使用GRI Mech. 3.0作為化學反應機制，並且將研究討論的重點專注於反應區內中間產物的生成以及火焰傳播機制及方式。從本研究的結果表明，藉由分析甲烷裂解所產生的Ｈ自由基可以用來標示三歧火焰的結構，二氧化碳在氧化劑流中的多寡會顯著地影響三歧火焰的傳播速度以及其火焰架構；結果顯示火焰會沿著特定的當量比等高線行進，火焰的動力學特性分析也顯示，甲烷火焰在氧氣/二氧化碳同軸流中的傳播仍以三歧火焰所主導，且其傳播行為會受自由基而有明顯的變化。

In the current study, the propagation characteristics of methane flames in O2 blended CO2 in laminar coaxial flow in a confined quartz tube were studied using numerical transient simulation and experiments. The fuel is pure CH4, and CO2 in O2/CO2 varies from 40% to 60%, with a 10% difference. The transient simulations of CH4-O2/CO2 flame propagation were modeled using GRI 3.0. This study characterizes the formation of the reaction zone and the transformation of flame-based propagation. The numerical investigation result showed that CO2 content in O2/CO2 mixture affects the triple flame speed propagation and triple flame structure by focusing on the H radical of CH4 decomposition known for methane pyrolysis and the rich side of the flame. The result also shows the flame base propagate along the preferred equivalent ratio isoline. The flame kinetic properties of the flame show that methane flame propagation in O2/CO2 coaxial flow is still dominated by the triple flame. The results also suggest that the triple flame propagation transformation is affected by the radicals as well as the chemical reactions.

[1] Festus, et al., Journal of Environmental Management, 266 (2020), article 110628
[2] Y.L. Xie, N. Lv, Q.Z. Li, J.H. Wang, Hydrogen Energy, 45 (2020), pp. 20472-20481
[3] L.G. Zheng, et al, Fuel 256 (2019), article 115913
[4] Y.L. Xie, et al, Energy Fuels, 27 (2013), pp. 6231-6237
[5] J.H. Wang, Z.H. Huang, Energy fuels, 27 (2013) 6231-6237
[6] F. Halter, F. Foucher, L. Landry, C. mounaim-Rousselle, Combust. Sci. and Tech., 181 (2009), pp. 813-827
[7] S.X. Wang, Z.H. Wang, Y. He, et al. Fuel, 259 (2020), article116152
[8] A. Rahbari, Gh. Barari. J Energy Eng, 142 (2016), article 04016009
[9] Y.S. Ko & S.H. Chung. CombustFlame, 118 (1999), pp. 151-163
[10] C.Y. Wu, Y.H. Li, T.W. Chang. CombustFlame, 159 (2012), pp. 2806-2816
[11] C.Y. Wu & K.H. Chen. Hydrogen Energy, 39 (2014), pp. 14109-14119
[12] Holmen, V. (2015). Direct Numerical Simulation and Modelling Study of the Structures and Propagation of Partially Premixed Turbulent Flames.
[13] K.A. Watson, et al. CombustFlame, 117 (1999), pp. 257-271
[14] G.R. Ruetsch, L. Vervisch, & A. Liñán. Phys. Fluids, 7 (1995) article 1447
[15] J. Boulanger, et al. CombustFlame, 134 (2003), pp. 355-368
[16] X. Qin, eat al. Combust. Theory Modelling, 8 (2004), pp. 293-314
[17] A. M. Briones, et al. CombustFlame, 153 (2008), pp. 367-383
[18] T.C. Williams, C.R. Shaddix. Combust. Sci. Technol. 179 (2007) 1225-1230
[19] L.G. Zheng, et al. Fuel 256 (2019), article 115913
[20] Bibzycki J, Poinsot T, Zajdel A. Arch Combust 2010, 4(30):287-396.