NH3/H2预混旋流火焰稳定性及燃烧极限实验研究

Experimental Studies on Flame St ability and Combustion Limit of Premixed NH3/H2 Swirl Combustion

采用叶轮型旋流燃烧器,选取氢气作为燃料添加剂,研究了掺氢比对氨气旋流火焰稳定性的影响,分析了不同旋流数、叶片数、当量比以及预混气总流量条件下,旋流火焰形态变化。测定并分析了不同参数对旋流火焰燃烧极限范围的影响。结果表明,随掺氢比的增大,火焰逐渐由“V”型转化为稳定的“M”型,燃烧反应愈发充分;高旋流数(1.27)或低叶片数(6片)相比低旋流数(0.42)或高叶片数(8片)更有利于旋流火焰的稳定和燃烧的充分进行;相比富燃,贫燃有利于形成稳定的旋流火焰;预混气总流量较大时,火焰高度较高.对于燃烧极限,掺氢比越高,极限范围越大;总流量的变化对贫燃极限影响较小,对富燃极限影响较大;高旋流数(1.27)条件下,燃烧极限范围较大。

With hydrogen adopted as the fuel additive,the effects of the hydrogen blend ratio on ammonia swirl flame were experimentally investigated using an impeller swirl burner.The variations of ammonia/hydrogen premixed swirl flame under different swirl numbers,impeller blade numbers,equivalence ratios and total flow rates were analyzed in detail.The combustion limits of swirl flame were experimentally measured and the influences of different parameters on the combustion limit ranges were analyzed.The results illustrated that the ammonia swirl flame tended to be more stable and the combustion reaction became more sufficient with the addition of hydrogen.A "V-M"flame structure transition was observed as the hydrogen proportion increased.Higher swirl numbers(1.27) or lower impeller blade numbers(6) were in favour of steadier swirl flames and more complete combustion reactions than lower swirl numbers(0.42) and higher impeller blade numbers(8).In contrast with fuel-rich conditions,swirl flames were more stable under fuel-lean conditions.Higher total flow rates resulted in higher swirl flame heights.As for the combustion limit,higher hydrogen blend ratio gave rise to wider range.The variation of total flow rates had limited effect on the lean flammability,while the rich flammability was very sensitive.The combustion limit ranges got wider under higher swirl numbers(1.27).