双旋流燃油燃烧器火焰特征研究

Experimental and Numerical Investigations of Diesel Diffusion Flame Structures on a Dual-Swirl Burner

利用OH平面激光诱导荧光技术,测量了双旋流燃油燃烧器扩散火焰特征,考察了不同当量比下火焰内部的OH摩尔浓度分布.应用FLUENT软件进行了数值分析,并将模拟结果与实验结果进行了比较,分析了不同当量比下,双旋流燃烧器柴油扩散火焰的结构特点与流场间的关系.结果表明,在双旋流燃烧器中,火焰出现在内外旋流器两股射流间的低速区域内;在燃料量不变、进气量加大的情况下,当量比低于0.38时,由于径向速度沿径向持续增大,导致火焰锋面被剪成前后两段;随着当量比的增大,火焰张角没有明显变化,但是燃烧区域显著增大.

The flame structures of diesel diffusion flame on a dual-swirl burner are observed by using OH-PLIF method at different equivalence ratio. FLUENT is used to analyze the fluid and OH distribution,and then the compu-tation results are compared with the experimental ones. The results show that,in the dual-swirl burner,the flame is located in the low velocity zone between two jet flows,that with constant amount of fuel and increasing amount of inlet air,the flame is cut into two when the equivalence ratio is lower than 0.38,and that with decreasing equivalent ratio,the angle of flame remains almost the same,while the combustion zone increases remarkably.