氨气预混旋流燃烧火焰稳定性及燃烧极限研究

Experimental Studies on Flame Instability and Combustion Limit of Premixed Ammonia Swirl Combustion

采用叶轮型旋流燃烧器,研究了旋流数、叶片数以及流量等因素对氨气预混旋流燃烧火焰稳定性和燃烧极限的影响.实验结果表明,在一定当量比下,氨气预混旋流燃烧火焰会失稳发生回火或振荡抬举;随着旋流数的增大或叶片数的增加,火焰更易失稳发生回火;石英玻璃高度越高,内部流场结构越完整,火焰高度越高。氨气预混旋流火焰贫燃极限在φ=0.64～0.76之间,富燃极限在φ=1.47～1.74之间。随着总流量的增大,贫燃极限逐渐增大,富燃极限波动较大,总体燃烧极限范围变大;随着旋流数的增大、叶片数的增加或石英玻璃高度的升高,燃烧极限范围变窄。

Ammonia swirl flame instability and combustion limit were experimentally investigated by an impeller swirl burner. The influences of swirl number, impeller blades numbers and flow rate were changed systematically. The results illustrate that under some certain equivalence ratios, ammonia swirl flame would lose stability with flashback and blowoff. The increase of the swirl number and impeller blades numbers would promote the occurrence of flashback. The quartz glass liner with height of 200 mm resulted in a fully developed flow field which increased the height of flame. Lean limit of ammonia swirl combustion was between φ= 0.64 and φ = 0.76, while rich limit was betweenφ = 1.47 and φ = 1.74. With the increase of total flow rate, lean combustion limit was narrowed down and rich combustion limit was fluctuated significantly, while the overall combustion limit was broadened. With the increase of the swirl number, impeller blades numbers and the height of quartz glass liner, the combustion limit range became narrower.