为了更深入地理解废气中二氧化碳对掺氢燃料燃烧特性的影响,在定容燃烧弹中利用高速摄像系统研究了不同燃空当量比咖(0.6~1.4)和稀释比(0%-40%)下CO2稀释氢气-空气混合气的层流燃烧特性.结果表明:氢气-空气混合气的火焰传播速率随着燃空当量比的增大而增大;马克斯坦长度随着当量比的增大而增大,即火焰的稳定性增强;随稀释比的增大,无拉伸火焰传播速率S1明显减小;同时得到层流火焰燃烧速率,并分析了稀释比对火焰稳定性的影响.通过对试验结果数据拟合,获得了计算氢气-CO2-空气混合气的无拉伸层流燃烧速率的拟合多项式.
Hydrogen-enriched hydrocarbon fuels are widely used in internal combustion engines, and exhaust gas recirculation is one of the most effective ways to decrease NOx emission from internal combustion engines. In order to investigate the effect of CO2 in exhaust gas on combustion characteristics of hydrocarbon fuels with hydrogen addition, the laminar combustion characteristics of hydrogen-air-CO2 mixtures are studied at different equivalence ratios ( Ф = 0.6--1.4 ) and different CO2 diluent ratios (0%---40% ). The results indicated that both flame propagation speed andthe Markstein length of hydrogen-air mixtures increases with the increase of equivalence ratio. By increasing diluent ratio, the unstretched flame propagation speed S1 decreases obviously. The effects of diluent gas on flame stability are also discussed in this paper. A polynomial fit to the data from experiments is also obtained, which can be used to calculate the unstretched laminar burning velocity of hydrogen-air-CO2 mixture .