STRUCTURE OF TURBULENT HYDROGEN JET DIFFUSION FLAMES WITH OR WITHOUT SWIRL

The near-field turbulent structure of double-concentric hydrogen-air j et diffusion flames, with or without swirl, has been investigated usin g conditionally sampled, three-component laser-Doppler velocimetry and coherent anti-Stokes Raman spectroscopy. The turbulent flame zone bec ame thinner and shifted inward as the mean jet velocity was increased, whereas swirl created a radial velocity even at the jet-exit plane, t hereby broadening and shifting the flame zone outward. The probability -density functions of velocity components, their 21 moments (up to fou rth order), mean temperature, and root-mean-square temperature fluctua tion were determined in the near field. The data can be used to valida te advanced turbulent combustion models.