锯齿形浓股出口结构下浓淡燃烧器出口区域的气固流场

应用颗粒动态分析仪测定了富集型煤粉燃烧器浓股出口加置锯齿型稳燃器前后的三维湍流速度场．试验结果表明,加置锯齿型稳燃器后,浓股气流在喷口附近的出口速度在三维方向上皆呈明显的波浪形分布,平均速度和脉动速度都有所增大,轴向平均速度衰减迅速,轴向脉动速度衰减延迟,水平径向和垂直径向的脉动明显增强．试验说明,锯齿型出口结构改善了喷口附近的气固流场,增大煤粉颗粒的局部空间浓度,增强气固混合,可以提高燃烧器着火稳燃和低NOx排放控制性能．

Effect of Tooth-Type Exit Structure on Gas-Solid Flow Field Adjacent to Exit of Dense-Dilute Burner

The tooth-type exit structure, a kind of flame stabilizer, was used in the dense flow tunnel of a dense-dilute type burner. The turbulent gas-solid flow field adjacent to the burner exit was measured by a 3-D phase particle doppler analyzer (PDA). Experimental results show that with the exit structure, both mean velocity and turbulent velocity are of a wave-like distribution adjacent to the burner exit. Along the jet, the mean axial velocity decays fast while the turbulent axial velocity decays more slowly. The turbulent velocities in horizontal and vertical directions increase significantly. The results indicate that tooth-type exit structure is useful to improve the flow field near the burner exit, enrich particulate concentration, enhance gas-solid mixing and reduce NOx exhaustion.