Measurement of flame front structure of turbulent premixed flames for CH₄/H₂/air mixtures

The measurement of the flame front structure of CH₄/H₂/air flames was conducted using planar induced laser fluorescence (OH-PLIF) to study the effects of hydrogen blending on the premixed turbulence-flame interaction of natural gas. Various turbulence conditions were generated by perforated plates with different hole diameters and opening ratios. The scales of the turbulent flow were measured and the properties of laminar flames were calculated. The effects of hydrogen addition, turbulence intensity and turbulence scales on the flame-turbulence interaction of CH₄/air turbulent premixed flames were discussed. The results show that the hydrogen addition significantly promoted the wrinkle intensity of the flame front, and the wrinkle intensity of the flame front increased with an increase in turbulence intensity. The flame height decreased slightly with an increase in hydrogen fraction and increased with an increase in turbulence intensity. The hydrogen addition facilitated the flame intrinsic instability, leading to the active response of laminar flame to turbulence and the highly wrinkled OH-PLIF flame front structure.