论文部分内容阅读
流体射入特定结构的突扩腔体会发生整体低频振荡,这类射流称为自激振荡射流。射流振荡对近场和远场的湍流混合过程都具有重要影响。自激振荡射流能增强宏观上的大尺度搅动,但同时却减弱了微观上的小尺度混合。以此为基础开发的自激振荡射流燃烧器能在不增加火焰长度的情况下增加火焰体积,显著提高火焰辐射换热,降低火焰温度,降低热力型氮氧化物(NOx)的生成。在工业水泥回转窑及其他窑炉的应用中,长期的实践证明,该燃烧器与以往的多喷嘴燃烧器相比,降低40%~60%的NOx排放,并降低了5%~10%的单位产量燃料消耗。该文综述了射流振荡对湍流混合及火焰特性的影响,亦对这种燃烧器的局限性做了分析讨论,最后给出利用自激振荡射流现象进一步发展工业燃烧器的建议。
Injecting fluid into a specific structure of the sudden expansion chamber will occur the whole low-frequency oscillation, this type of jet is called self-oscillating jet. Jet oscillation has an important influence on the turbulent mixing process in near-field and far-field. Self-oscillating jets enhance macroscopic large-scale agitation, but at the same time weaken microscopic, small-scale mixing. The self-oscillating jet combustor developed on this basis can increase the volume of the flame without increasing the length of the flame, significantly improve the radiation heat transfer of the flame, reduce the flame temperature and reduce the formation of the heat-type nitrogen oxide (NOx). In the application of industrial cement rotary kilns and other furnaces, long-term practice has proved that this burner reduces NOx emissions by 40% -60% compared to conventional multi-nozzle burners and has a reduction of 5% -10% Unit output fuel consumption. This paper summarizes the effects of jet oscillation on turbulent mixing and flame characteristics. The limitations of this type of combustor are also analyzed and discussed. Finally, some suggestions for the further development of industrial burners using self-oscillating jets are given.