Effect of gas composition and initial turbulence on the propagation dynamics of premixed flames of hydrogen-blended natural gas fuel

Abstract

In order to reduce carbon emissions, the effects of gas composition and initial turbulence on the premixed flame dynamics of hydrogen-blended natural gas were investigated. The results show that an increase in hydrogen content leads to earlier formation of flame wrinkles. When the equivalence ratio is 1 and hydrogen blending ratio is below 20 %, Tulip flames appear approximately 2.25 m away from the ignition point. When hydrogen blending ratio exceeds 20 %, Tulip flames appear approximately 1.3 m away from the ignition point, and twisted Tulip flames appear approximately 2.5 m away from the ignition position. During the 0.05 m process of flame propagation downstream from ignition point, flame propagation velocity increases by about 2 m/s for every 10 % increase in hydrogen content. The increase in hydrogen content has the most significant impact on the flame propagation velocity during the ignition stage. The average flame propagation velocity increases with the increase of hydrogen blending ratio. The greater the initial turbulence, the more obvious the stretching deformation of flame front structure. With the increase of wind speed, the flame propagation velocity first increases and then decreases. At a wind speed of 3 m/s, the flame propagation velocity reaches its maximum value.

Keywords

• Hydrogen-blended natural gas fuel
• Flame front structure
• Flame propagation velocity
• Component effects
• Initial turbulence