碩士生: 彭冠勛
畢業年分: 2020年7月
論文名稱: 甲烷/氫氣預混火焰於帶有穿透孔之不鏽鋼/鉑觸媒隔板反應器之燃燒特性研究(中文) / Combustion characteristics of methane-/hydrogen-air premixed flames in the combined steel-platinum catalytic partition reactor with a percolated hole (英文)
中文摘要:
本研究主要探討具有穿透孔之不鏽鋼/鉑觸媒隔板反應器的燃燒性能與火焰穩駐機制，並使用Kriging模型優化整體系統之燃燒效率。觸媒微燃燒器是由分段式觸媒是由鉑與不鏽鋼接合組成，而分段式觸媒平板將主燃燒器分成兩個區域。氫氣−空氣混合氣與甲烷−空氣混合氣分別注入於兩側流道之中。在過去的研究中，反應器上的穿透孔不僅可以提供一個低速流區域以穩駐微火焰，還可以促使兩側流道的燃燒化學物質與自由基藉由擴散或流入進行誘發氣相火焰生成。
比較傳統平板燃燒器與具有穿透孔的平板燃燒器之模擬結果顯示，具有穿透孔的燃燒器在不同的燃氣條件下，呈現較高的甲烷−空氣之燃燒效率。其主要的原因是在穿透孔附近的氫氣-空氣燃燒反應提供所產生的化學熱能與自由基，可以有效地輔助另一微流道中的甲烷−空氣觸媒誘發預混火焰。然而，氫氣-空氣預混火焰的樣態會影響另一側流道的甲烷−空氣觸媒誘發預混火焰之穩住機制，其火焰穩住機制易遭受到兩側流道的燃氣當量比例，以及燃氣流速比不同而衍生出的溫度與速度梯度不平衡，進而影響燃燒穩定性與燃燒效率。
最後，本研究採用Kriging模型對具有穿透孔的燃燒器進行操作參數與系統參數進行甲烷−空氣燃燒效率之優化，綜合優化結果得知甲烷−空氣流速是影響甲烷−空氣燃燒效率最大的參數，其次是:白金孔洞位置、甲烷−空氣當量比。影響最低的參數是氫氣−空氣流速以及氫氣−空氣當量比。系統優化最佳條件為甲烷−空氣當量比為 0.7，甲烷−空氣流速為 5 m/s；氫氣−空氣當量比為 0.9 ，氫氣−空氣流速為 10 m/s、穿透孔位置為 15 mm。
英文摘要:
This study aims to investigate the combustion efficiency and combustion stabilizing mechanism of the combined steel-platinum catalytic partition reactor with a perforated hole. Then, the optimal Kriging model is employed to optimize the overall combustion efficiency of the proposed micro combustion system. The micro catalytic combustor was partitioned by the combined stainless steel-platinum plate(s) into two channels. Hydrogen-air and methane-air mixtures were injected into each channel individually. In the previous study, the gap provided a low-velocity region to stabilize the catalytically-stabilized premixed flame and space to trade the species and radicals diffusing or flowing from both channels, leading to the inception of gas reaction.
Compared the simulation results of the micro flat combustor (FC) and flat combustor with a hole (FCH), it is obvious to note that the methane-air combustion efficiency of the FCH is much higher than that of the FC. The reaction in the vicinity of the perforated hole provides thermal energy and sufficient radicals to sustain the methane-air flame in the upper channel. However, the parameters of the combustor configuration also had been discussed, such as the hole location and hole size. It is interesting to note that the flame modes of the hydrogen-air mixture in the lower channel would affect the flame stabilizing mechanism and combustion efficiency of the methane-air mixture in the upper channel. It is due to the imbalance of thermal and velocity gradients in the vicinity of the perforated hole.
In this study, the kriging model was used to optimize the operational and design parameters of the FCH for maximizing the combustion efficiency of the methane-air mixture. The results indicated the order of the utmost influencing parameter is the flow rate of the methane-air mixture, the location of the perforated hole, and the equivalence ratio of the methane-air mixture. The insignificant parameters are the flow rate of the hydrogen-air mixture and the equivalence ratio of the hydrogen-air mixture. Consequently, the optimal condition of the combined steel-platinum catalytic partition reactor with a perforated hole is the equivalence ratio of the methane-air mixture = 0.7, the flow rate of the methane-air mixture = 5 m/s, the equivalence ratio of the hydrogen-air mixture = 0.9, the flow rate of the hydrogen-air mixture = 10 m/s, and the location of the perforated hole is 15 mm away from the combustion basement.
