相向噴流衝擊擴散火焰穿透分析

A Study on Obverse Jet Impinging Diffuse Flame

何達義(Hao-Dar Yee)

指導教授 ： 蘇艾

元智大學/工程學院/機械工程學系/碩士(2000年)

摘要

本實驗主要在研究相向噴流衝擊擴散火焰燃燒現象，以等質量流率的甲烷燃料與鈍性氮氣對衝，藉由控制燃料流率使用不可燃氮氣與甲烷燃氣衝擊後之狀況，來觀察火焰彼此穿透的結構變化。由於氮氣具有吸熱不可燃特性，在觀察氮氣與甲烷衝擊後之等溫圖，可從焰內溫度變化很容易找出彼此衝擊後的穿透深度。由焰形及紋影顯示，火焰燃燒相當對稱，但燃燒的流場變化大時，整個火焰溫度是非對稱型態，所以量測整個火焰場數據來擷取資料，本實驗流率採用250ml/min(Re=81)，350ml/min(Re=113)，450ml/min(Re=145)等三種，並同時採用甲烷－甲烷對衝及氮氣－甲烷對衝等二種方式研究，實驗結果(1)流量調大後衝擊深度並不會跟著加深，焰溫亦不會隨著昇高；(2)由雷諾數為113，流量350ml/min，純甲烷燃燒時發現，燃料加倍並不能使燃燒效果增加 ，相反的會無謂的浪費有限的資源。(3)當甲烷流量為350ml/min，以等流率氮氣對衝時，在流率相等，衝擊點在正衝線上，外在空氣充足，均勻燃燒的情況下，會得到較大的穿透深度，所以根據觀察和實驗, 相向噴流衝擊擴散火焰表現的比相向噴流擴散火焰來的更為穩定均勻和有效率。

關鍵字

噴流火焰 ； 擴散火焰 ； 相向噴流衝擊擴散火焰

並列摘要

The experiments invest major on the reverse jet-pumping diffusion flame of burning phenomenon by using equal-mass-fluid-rate to observe the methane fuel and forbid burn nitric of face-to-face-pump phenomenon. And observe the penetration flame configuration change each other with control fuel-fluid-rate. Because forbid burn nitric has the character of endothermic and forbid burn. So, in observing face-to-face-pump of the methane fuel and forbid burn nitric of isothermal pictures , we can be from the change of flames temperature finding out the penetrating depth of jet-impinging diffusion flame .By experiment and observation, the pulsating flame behaves more stable and efficient than the continuous impinging flame. From the frame type and the veins shadow , the flames are normally symmetry. But when the fuel fluid rate varies large, the total flame temperature is non-symmetry , So, we measure the total flame field to get the detail data.
The experiment of fluid rate uses following three type sources, 250ml/min(Re=81), 350ml/min(Re=113) and 450ml/min(Re=145). And the experiment also separate two type to study ; The first type is methane fuel to methane fuel; The second type is methane fuel to forbid burn nitric.
The experimental results have following three point:
(1) If the fluid rate adjust large , the pulsating depth of flame isn’t large and the flame temperature isn’t rising.
(2) If the Renold Number is equal to 113 and the fluid rate is 350ml/min , adds twice the pure methane fuel, the combustion effects isn’t increasing.
(3) If the methane fuel fluid rate is equal to 350ml/min, the natural air is full, the combustion is well mixed, the pulsating point is on the upright pulsating line , and use equal fluid rate of forbid burn nitric pumping each other, we can obtain more large penetrating depth.
Recording to observation and experiment, the reverse jet-pumping pulsating flame is more stable and efficient the reverse jet-pumping diffusion flame of burning phenomenon by using equal-mass-fluid-rate.

並列關鍵字

impinging flame ； diffusion flame ； Obverse Jet Impinging Diffuse Flame

參考文獻

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