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对丙烷/空气在内径2 mm的圆管内的预混燃烧进行了实验研究,借助于高速数码摄像机发现了分裂火焰现象,其中一个为向上游传播的较亮的常规火焰,另一个为向下游传播的较暗的微弱火焰。这些火焰先后熄灭,经过一段时间后又重复发生自着火、分裂、反向传播、灭火过程。这种现象在富燃、化学恰当比以及贫燃火焰中都有存在。一维非稳态计算表明化学反应速率的轴向分布曲线存在大小不同的两个峰值,它们分别对应实验观察到的两个不同亮度的火焰。其中,常规火焰是由于向上游较冷的壁面散热而熄灭,微弱火焰则是由于下游燃料耗尽而熄灭的。
Experimental studies on premixed combustion of propane / air in a tube of 2 mm inside diameter were performed with the aid of high-speed digital video cameras to detect the phenomenon of split-fire, one of which is a relatively bright, conventional flame propagating upstream and the other is downstream Dark, faint flame. These flames went out one after another, and after a period of time they repeatedly occurred from burning their fires, splitting up, spreading backwards and extinguishing fires. This phenomenon exists in the rich, the proper chemical ratio and the flame of lean burn. The one-dimensional unsteady calculations show that there are two peaks of different sizes in the axial distribution curve of the chemical reaction rate, corresponding to the two flames of different brightness experimentally observed. Among them, the conventional flame is due to the cooling of the upper reaches of the wall heat to extinguish the faint flame is due to depletion of the downstream fuel and extinguished.