DNS of a turbulent premixed jet flame with fully developed turbulent inlet

Abstract

A Direct Numerical Simulation (DNS) study is conducted of a premixed round jet flame with a fully turbulent flow exiting a long pipe as inlet condition. The inclusion of the pipe in the simulation with a fully turbulent flow inside ensures that the turbulence-flame interaction, in particular near the inlet region, is well represented. The orientation of turbulence structures in different regions of the domain is identified. The interaction between the turbulence structures and the flame is examined using vector alignments. Streamwise oriented vortical structures formed in the pipe boundary layer are convected into the base of the flame. Preferential alignment of the flame normal with the compressive eigenvector of the strain rate tensor is observed close to the pipe exit suggesting that the turbulence characteristics of the jet inlet have an effect on the flame front close to the flame base.