碩士生: 戴明偉
畢業年月: 2024年8月
論文名稱: 碳氫火焰輔助氨/空氣燃燒過程中的熵生成率和NOx排放機制之數值研究 / Numerical study of NOx emission and entropy generation in ammonia/air combustion with assistance of hydrocarbon/air flames
中文摘要:
氨燃燒涉及MILD燃燒與富—熄—貧燃燒等複雜現象。本研究以簡化三口燃燒器，數值探討碳氫母火輔助的氨燃燒，設定Case 1為CH4/空氣、Case 2為（90% CH4＋10% H2）/空氣、Case 3為C2H6/空氣，採用Star CCM+搭配Glarborg詳細反應機制，辨識出瞬發NO、燃料NO與三條熱NO路徑（NNH、HNO、N2O）共六種生成途徑。母火中添加氫氣或改用乙烷可顯著抑制NO：Case 3的燃料NO路徑減少75%、瞬發NO減少12.5%，整體NO質量分數在Case 2與Case 3分別降低10%與31%。可用能分析顯示各案例歸一化後比例相近，表示在減少NO的同時維持可用能。
英文摘要:
Ammonia combustion involves complex phenomena such as MILD and rich-quench-lean modes. This thesis numerically studies ammonia combustion assisted by hydrocarbon pilot flames in a simplified three-port burner, with Case 1 CH4/air, Case 2 (90% CH4 + 10% H2)/air, and Case 3 C2H6/air, using Star CCM+ and the detailed Glarborg mechanism. Six NO routes are identified: prompt, fuel, and three thermal sub-routes (NNH, HNO, N2O). Adding hydrogen to the pilot flame or replacing methane with ethane significantly suppresses NO: the fuel NO route falls by 75% and prompt NO by 12.5% in Case 3, and overall NO mass fraction falls by 10% in Case 2 and 31% in Case 3. Exergy analysis shows similar normalized ratios across cases, so these measures cut NO while maintaining exergy.
