2005 Volume 30 Issue 2 Pages 58-65
It is important that the effect of dilution gas on the turbulent burning velocity of hydrogen mixtures is elucidated to develop modern hydrogen combustion devices. In our previous studies, the preferential diffusion effect was made clear to play an important role in the turbulent combustion characteristics, affecting the local burning velocity, where nitrogen was added as a dilution gas to several fuel/air mixtures. The present study is performed to obtain experimentally the turbulent combustion characteristics of dilution gas added lean hydrogen mixtures with special attention to the local burning velocity of turbulent flame, in order to elucidate the mechanism of turbulent combustion of those mixtures. In this study, the turbulent burning velocities of the prepared mixtures, whose laminar burning velocity were nearly the same and the equivalence ratio were varied, w ere experimentally investigated. Where, argon, helium and carbon dioxide in addition to nitrogen were adopted as dilution gas. It is found that carbon dioxide added mixtures show larger turbulent burning velocities than that of nitrogen added mixtures at the same equivalence ratio. On the contrary, helium added mixtures show very smaller turbulent burning velocities. Those characteristics are discussed in preferential diffusion effect, turbulent flame-front configurations and Markstein number.
