噴流擴散火燄最主要的特徵為火燄的動態現象，一般來說，噴流火燄隨出口速度增加除從層流火燄轉變為紊流火燄，也會產生跳脫(lift-off)、吹熄(blow-out or blow-off)、遲滯(hysteresis)與回駐(reattachment)等動態現象，這些現象包含相當複雜的流體與火燄相互作用機制與穩定特性，若能增加此動態特性的了解，對燃燒系統的設計以及運作有莫大的幫助。
在本研究中，回顧近年來發展的紊流噴流跳脫火燄的穩駐機制，發現三歧火燄跟跳脫穩駐有很大的關係，另一方面，經由適當的改變預混甲烷/一氧化碳/空氣中的燃料組成比例或是燃料混合空氣之當量比，火燄的層流燃燒速度可以達到最大值。
因此，依據紊流噴流其部份混合(partially premixed)的特性與甲烷/一氧化碳混合燃料其特殊的層流火燄速度現象來探討在靜止空氣中的紊流跳脫火燄之穩駐特性。實驗方法是利用一噴流燃燒器、CCD數位硬碟式攝影機、非介入式的雷射粒子影像測速儀，藉由調整噴嘴出口速度來觀測不同混合比例的燃料之跳脫火燄影像、跳脫高度、火燄底端速度分佈。從實驗結果發現，此混合燃料的噴流火燄跳脫特性介於純甲烷與純一氧化碳之間，大約以10%甲烷90%一氧化碳之比例為轉變點，而此穩駐的特性改變可藉由理論的濃度分佈曲線以及火燄底端的速度場分佈比較，推論出可能隨著一氧化碳增加至80%時，純甲烷的三歧火燄穩駐特性會轉變為由甲烷/一氧化碳混合燃料的最大層流火燄速度主導，而當增加至90%的一氧化碳時，火燄穩駐特性會有所改變，除了變為直接吹熄(blow-off)之外，利用降低噴嘴出口速度而從下游再次引燃的方法，發現火燄底端的速度分佈也跟三岐火燄的特性不同。

The dynamic mechanism of a non-premixed jet flame are important characteristics considerably. In general, when velocity of nozzle exit is increased to the limit value, the laminar jet flame will transfer into turbulent jet flame, in addition to generate the typical phenomenon of the lift-off, blow-out/off, hysteresis and reattachment which involved with these complex features of flame-flow interactions and fundamental combustion stability. It is useful to design and operate the combustor with more knowledge of this dynamic property of jet flame.

In the present study, the developmental theories and assumption of stabilization mechanism of lifted turbulent jet diffusion flames are reviewed, some commentary suggest that there are significant relation between the triple flame and flame-lifted stabilization. On the other hand, the laminar flame speed of premixed CH4/CO/air can attain maximum when change applicably the composition of CH4/CO mixture fuels or equivalence ratio of fuel/air.

Hence, the stabilization characteristics of CH4/CO lifted turbulent jet flames in still air are explored by the partially premixed behavior of axisymmetric turbulent jet and the exceptional laminar burning velocity of CH4/CO/air flames. A systematic experiment is conducted in this investigation with a jet burner, a CCD digital camera and the non-intervened laser diagnostic technique (Particle Image Velocimetry) to observe the instantaneous flame-lifted images, the lift-off height and velocity data of flame base by adjusting the exit velocity and blended fuel concentration. Results show that the lift-off characteristics of this jet flame will change from pure methane into pure carbon monoxide at the fuel composed of 10% methane and 90% carbon monoxide. According to compare the theoretical model of fuel concentration distributing in still air and the velocity field in flame base, we predict the stabilization characteristics which is determined by the triple flame in pure methane will transfer into the specific criterion of maximum laminar burning velocity of blended fuels. The jet flame don’t turn into blow-out but become the blow-off, furthermore the characteristics of velocity field in flame base which used by reigniting from downstream again with decreasing the exit velocity are distinct from the triple flame when CO content is further increased over 90%.

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