甲烷/氢气混合燃料贫预混旋流燃烧特性数值研究

Numerical Study of Combustion Characteristics of Methane/Hydrogen Hybrid Fuel of Lean Premixed Swirl

采用数值模拟的方法,对燃气轮机燃烧室使用甲烷/氢气混合燃料时的混合比例对燃烧室的燃烧特性和污染物排放特性的影响开展了研究.结果表明:由于燃烧化学反应的作用,冷态和热态流场结构存在一定的差异,热态流场流速增高,回流区变大.氢气含量对燃烧室内热态流场的结构和温度分布特性会产生明显影响,氢气含量小于20%时形成中心回流区,可以维持稳定燃烧;氢气含量大于40%时,中心回流区消失,角回流区延长,出现了不同程度的自燃和回火现象;燃烧室进气温度越高自燃现象越明显,进气温度越低回火现象越明显;NO_(x)排放量随着氢气含量增加而增大,CO排放量随着氢气含量增加而减少,CO集中分布在主燃级燃烧区.

The numerical simulation method is used to study the influence of the mixing ratio of methane/hydrogen mixture on the combustion characteristics and pollutant emission characteristics of the combustor.The results show that due to the action of combustion chemical reaction,there exists a certain difference in the structure of cold and hot flow fields.The flow velocity of the hot flow field increases,and the recirculation zone becomes larger.The hydrogen content has a significant impact on the structure and temperature distribution characteristics of the hot flow field,and a central recirculation zone is formed when the hydrogen content is less than 20%,which can maintain stable combustion.When the hydrogen content is greater than 40%,the central recirculation zone disappears,the external recirculation zone is extended,and the spontaneous combustion and flashback occur to varying degrees.As the inlet air temperature increases,the spontaneous ignition phenomenon becomes more obvious,and the inlet air temperature decreases,the flashback phenomenon becomes more obvious.NO_(x) emissions increase with the increase of hydrogen content,CO emissions decrease with the increase of hydrogen content,and CO is concentrated in the combustion zone of the main combustion stage.