本論文實作研究一低氮氧化物(NOX)氫燃燒器，採用先前Bédat & Cheng (1995)所提出之弱漩渦噴流燃燒器(weak swirl jet burner, WSJB)的設計概念，在燃燒器上游出口設置一弱噴流漩渦產生器(weak jet-swirl generator)，它乃由四支20o向上斜角設計之切邊小噴嘴所構成，可在燃燒器出口下游處，形成一均勻擴張流場(diverging flow field)，使原本生燈噴流預混火焰呈一穩定之碗狀預混火焰。並配合本實驗室先前所設計之快速混合裝置及貧油甲烷加氫紊流燃燒技術，由純甲烷燃氣開始，逐漸增加加氫量至純氫燃料，成功地建立一低氮氧化物氫燃燒器。實驗探討於不同甲烷/氫氣混合比例及純氫燃料條件下，燃燒器的穩定操作範圍及應用高速質點影像測速儀(particle image velocimetry, PIV)和氣體分析儀分別量測不同氫燃料比例之紊流燃燒速度(turbulent burning velocities, ST)和[NOX]排放物濃度。實驗結果顯示：添加氫氣可有效擴展甲烷貧油可燃極限並提高ST值；在當量比? = 0.4，所有加氫後之紊流預混火焰，其[NOX]值均低於5 ppm，甚至在純氫燃料時，[NOX]幾無任何可以量測之值。本研究更首次利用化學螢光法(chemiluminescence measurements)分析火焰特性，利用不同波段透鏡擷取火焰的輻射光，經由Abel 轉換技術，針對所接收化學螢光的波長範圍，分別為氫氧基(OH*)介於305 nm 與315 nm 之間、碳氫基(CH*)介於425 nm 至445 nm 之間、雙碳基(C2*)介於465 nm 至475nm 或505 nm 至520 nm 的範圍內作分析，以獲取火焰燃燒相關化學反應之資訊。上述研究成果對無碳氫燃燒技術之研發有重要之助益，因本燃燒器同時具備了可大幅度降低[NOX]之功能。 This thesis studies experimentally a low NOX hydrogen burner, adopting the design of the weak swirl-jet burner (WSJB) proposed by Bédat & Cheng (1995) with new modifications using a rapid mixing mechanism and the hydrogen doping lean premixed turbulent methane combustion technology previously developed by our laboratory led by professor Shy. The weak jet-swirl generator is equipped at the exit of the burner, composed of four small circumferential jets inclined at 20°, capable of generating a uniform diverging flow field in the downstream of the burner exit, so that the original Bunsen-type jet flame can be stabilized in a form of the bowl-shape flame with very low NOX emissions. Furthermore, the abovementioned new modifications are used to make the burner more compact and to develop a pure hydrogen burner by gradually increasing the amount of doping hydrogen. Specifically, the flame stable operation domain of the burner is studied using different volume ratios of lean CH4/H2 mixtures and finally to pure H2 mixtures. Turbulent burning velocities (ST) and [NOX] emissions are then measured by a high speed particle image velocimetry (PIV) and the gas analyzer, respectively. The result shows that by adding hydrogen the lean flammability limit of methane can be effectively extended and values of ST at any given values of equivalence ratios (?) and root-mean-square turbulent fluctuating velocities (u') can be increased. All measured [NOX] values for CH4/H2 flame are found to be lower than 5 ppm, while for pure H2 flames at ? = 0.4 no measurable [NOX] can be found. This study also applies chemiluminescence measurements to analyze the flame characteristics, using appropriate lenses with different wavelengths. The Abel inversion is then applied to analyze these flame appropriate chemiluminescence data which should be related to various. The selected wavelengths for chemiluminescence species include hydroxyl (OH*) between 305 nm and 315 nm, hydrocarbon-based (CH*) ranging from 425 nm to 445 nm, and dual-carbon (C2*) from 465 nm to 475nm or from 505 nm to 520 nm. As a final remark, these results should be of help to the future development of carbon-free hydrogen combustion technology with extremely low NOX emissions.
