ODT Closure with Extinction and Reignition in Piloted Methane-Air Jet Diffusion Flames

Abstract

A novel tabulation procedure for reactive scalar statistics based on the one-dimensional turbulence (ODT) is implemented to study extinction and reignition in piloted methane-air jet diffusion flames. The formulation is based on constructing the scalar statistics from stand-alone temporal jet simulations using ODT. The statistics are correlated in terms of two parameters based on a single transported variable: the mean mixture fraction, which measures the extent of mixing between the fuel and oxidizer streams, and the centerline mixture fraction, which measures the extent of entrainment into the fuel jet or the jet evolution downstream. The evolution of momentum and passive scalars is computed using a Reynolds-Averaged Navier-Stokes (RANS) formulation, which uses the 2D table for look-up of the mean density. Other reactive scalars' profiles are obtained from the 2D table and the computed momentum and scalar fields from RANS. Comparison of the computed and the experimental statistics for momentum and scalars shows that the tabulation scheme along with the RANS model yields reasonable predictions of the processes of extinction and reignition in piloted jet diffusion flames.

Keywords:

• ODT-based closure
• Piloted-jet diffusion flames
• Turbulent non-premixed combustion

We are grateful to Prof. A. Dreizler for providing us the velocity data for Flames D and F and to Drs. R. S. Barlow and J. F. Frank for providing the scalar data through the TNF workshop Web site.

Notes

The velocities represent bulk properties at the fuel jet, the pilot, and the co-flow.