多孔性圓柱預混燃燒器尾流火燄之穩定性分析研究

Premixed wake flame in a porous cylindrical burner

林文昌(Wen-Chang Lin)

指導教授 ： 潘國隆

國立臺灣大學/工學院/機械工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01315

摘要

本文以貧油燃燒為主軸，使用不繡鋼管圓柱直徑13.7mm、長度4.7mm、孔隙40μm、孔隙率69%。利用多孔介質圓柱之特性將預混燃料均勻地噴出並產生穩定火燄。探討自然對流與強制對流場下，流場對多孔介質圓柱火燄燃燒器造成的影響。此外亦改變雙圓柱間距徑比L/D，並比較單圓柱、雙圓柱預混燃燒的貧油可燃極限、熱損失、駐燄效果。
實驗結果顯示，圓柱直徑(D)與速度梯度成反比，火燄熄滅速度梯度隨L/D變小而增大。自然對流場下的單(雙)圓柱預混燃燒貧油可燃極限均為0.33。強制對流場下的單圓柱預混燃燒貧油可燃極限為0.39，雙圓柱預混燃燒可燃極限與L/D有關，L/D=1.02、1.2、1.4貧油可燃極限分別為0.33、0.37、0.39。雙圓柱預混燃燒可燃極限操作範圍將隨距徑比L/D減少而變大、其熱損失愈少、駐燄變佳，利用火焰間保護與交互作用，而達到拓展貧油可燃極限之目的。

關鍵字

多孔介質圓柱 ； 貧油燃燒 ； 貧油可燃極限 ； 包絡燄 ； 側燄 ； 尾燄

並列摘要

An experimental study to investigate the effect of the forced convection and natural convection flow field on the combustion of cylindrical porous medium is presented.
The lean combustion using the cylindrical porous medium as burner ejected the mixing air-fuel uniformly to produce a stable flame. In addition, using different L/D to determine the lean flammability limits value、heat loss and flame stability mechanism between the single cylinder burner and double cylinder burner has been discussed in this study.
The result shows that the cylinder diameter is the negative correlation of gradient velocity. The increasing gradient of flame extinction velocity is relative a decreasing L/D. In natural convective fluid field, the lean flammability limit of premixed flame combustion is 0.33; in forced convective fluid field, single cylindrical burner of the lean flammability limit of premixed flame combustion is 0.39. Double cylindrical burner of the lean flammability limit of premixed flame combustion and L/D are related. When L/D=1.02、1.2、1.4,the double cylindrical burner of the lean flammability limit of premixed flame combustion are 0.33、0.37、0.39. lean flammability limit is corresponded the objective of expanding lean flammability limit by flame interaction.

並列關鍵字

cylindrical porous ； lean combustion ； lean flammability limits value ； envelope flame ； side flame ； wake flam

參考文獻

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