Abstract: A piloted CH₄/O₂/N₂ turbulent jet non-premixed flame (Sandia flame D) is numerically investigated.The summary of the adopted models contains a two-scale k-ε turbulence model,the scalar joint probability density function (PDF) transport equation approach,the augmented reduced mechanism (ARM) for methane oxidation (consisting of 16 species and 12 lumped reaction steps),the Euclidean minimum spanning tree (EMST) small scale mixing model etc.The agreements between the numerical results and the experimental data are good,including the scatter plots and conditional PDFs of scalars as well as the scalar averages.The numerical results indicate that the present models are not only able to represent the macro flame structure accurately,but also can successfully predict the complicated local extinction and re-ignition processes in the turbulent combustion.

Key words: turbulent non-premixed flame, local extinction and re-ignition, PDF transport equation method, numerical simulation