本文主要研究非同質相向噴流衝擊火焰三維結構,相向衝擊火焰架構中,以不可燃氮氣替代另一支燃料管,經由調整不同質衝量比條件觀察火焰燃燒結構。本文藉由非同質相向噴流(Un-like jet impingement),可將擴散火焰結構透明化,以分析火焰貫穿深度及燃燒穩定性。 實驗主要是將噴嘴固定在72.5度衝擊角度參數條件下,探討不同燃料流速、甲烷與氮氣不同衝量比條件下,研究相向噴流擴散火焰的結構特性,以及火焰與流場所產生結構的變化與火焰穩定性的影響。研究目標是求得在不同衝量比條件下,噴流的Re(或速度)對穿透性與火焰結構的影響,並找出最佳的衝量比趨勢。在同質燃燒條件下,火焰結構包含兩個噴流的衝擊結果,但不易看出混合效益或穿透深度。但由本實驗以氮氣取代另一支噴流,不可燃特性的氮氣,在相向噴流火焰結構內,提供明顯的混合關係。 由XY平面溫度圖及Schlieren光學觀測,在五組衝量比條件中,當甲烷及氮氣衝量比為1:1時,火焰燃燒場平均溫度、高溫區及火焰結構穩定性為所有衝量比搭配中最佳。非同質相向噴流擴散火焰藉由有效控制氮氣與甲烷對衝衝量比,使燃燒場內高溫區能夠集中且穩定作用,火焰內部溫度的瞬時變化將會減至最低,而有助於控制燃燒室火焰燃燒溫度及火焰高度。 關鍵字:相向噴流擴散火焰、非同質燃料、氮氣
The subject of the study is the 3-dimention structure of un-like jet impingement diffusion flame. In the structure of impingement flame, a un-combustibility nitrogen fuel pipe replaces another methane one. By different conditions of mass momentum, we observe the flame structure. Un-like impingement flame supplies a transparent flame structure to analysis the depth of penetrating and the burning stability. In the impingement angle condition of 72.5 degree, fuel velocity and momentum influence the streamline and the stability of flame. The goal of this study is to find the effects of Re and the best momentum ratio. Un-combustibility nitrogen provides an obviously mixing relation. From XY diagrams and Schieren optics observation, in the five momentum conditions, while the methane-nitrogen momentum is 1:1, the average temperature, high-temperature region, and stability are the better than other conditions. By controlling the mass momentum, the centralizing high-temperature region is stable and helpful to control the flame temperature and height. Keywords:impingement diffusion flame, un-like fuel