衝擊角度對衝擊噴流脈衝火焰之研究

A Study on Impinging Angle Effect on Jet-to-Jet Impinging Pulsation Flame

徐可能(Ke-Neng Shu)

指導教授 ： 蘇艾

元智大學/工程學院/機械工程學系/碩士(2001年)

摘要

本實驗主要在研究不同衝擊角度條件下，衝擊噴流脈衝火焰之燃燒溫度場變化。本實驗將電磁閥成一直線的排列方式裝設於直管噴嘴上游的位置，利用 2 Hz 到 17 Hz之間的開閉週期，控制甲烷燃料及出口流場條件，並藉由改變衝擊角度、燃料出口雷諾數與燃料供應脈衝頻率等參數，來探討相向噴流擴散火焰之溫度場變化。實驗結果顯示：經由電磁閥做為衝擊噴流火焰源頭，提供規律性擾動源，增加氣流紊流強度，獲得較佳之火焰穩定性；頻率約13Hz~15Hz間的火焰高度皆較無脈衝頻率時為低，且衝擊角度為54度有較明顯的矮化現象，可改善燃燒的設計長度；由平面溫度場的觀察，當改由電磁閥做為燃料供應的源頭，因頻率間斷吸入較多的空氣量，火焰內部參與反應的燃氣分子數量增加，而使燃氣燃燒較完全，火焰溫度場在操作頻率約13Hz時會得到較佳的燃燒效果；整體而言，最佳的操作頻率約為13Hz，且頻率在10Hz以下，會產生不連續燃燒結果，增加火焰不穩性。

關鍵字

脈衝 ； 擴散火焰

並列摘要

Experimental investigations on the pulsating jet-impinging diffusion flame were executed. A solenoid valve was aligned upstream of the jet orifice and the methane fuel and the outlet-field condition were controlled in open-closed cycles from 2 Hz to 17 Hz. By changing some parameters such as impinging angle, outlet fuel Renault Number and fuel supplying pulsation frequencies, to confer the changing of the temperature contours of a impinging jet diffusion flame. Results show that a solenoid which is the impinging jet flame source supplying a regular disturbing fountainhead to increase the turbulence flow strength can get better flame stability; the flame length between 13 Hz to 15 Hz was lower than that without pulsating, and the impinging angle at 54 degree with more obviously shorting phenomenon can improve the designed length of the burning room; observing temperature contour plane, a solenoid as a fuel supplying source can burn the fuel more completely because the reacting fuel molecules in the flame increase as a result of sucking more air by interrupted frequency. We can get a better burning efficiency when the operating frequency at about 13 Hz in flame temperature contours. Results show that the best operating frequency is at about 13 Hz, and if the frequency were below 10 Hz, it would result an uncontinuous burning and decrease the stability of the flame.

並列關鍵字

pulsating ； diffusion flame

參考文獻

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