Stabilization of piloted turbulent flames with inhomogeneous inlets

The flame with inhomogeneous inlet conditions is more stable being at 57% of blow-off compared to the homogeneous counterpart, which is at 78% of blow-off. It is found that, very close to the jet exit plane, premixed combustion dominates the flame with an inhomogeneous profile. This is in contrast to the homogeneous case, which behaves like a diffusion flame. Further downstream, but still within the pilot region, partial mixing starts to occur between richer samples and hot combustion products. A comparison of the relative conditional scalar dissipation rates, χr shows that in the upstream region, and within the reactive limits, the homogeneous case has higher values of χr. Premixed combustion with higher rates of heat release and lower scalar dissipation rates in the near field are therefore key reasons for the improved stability of the flames with inhomogeneous inlets. These findings are corroborated by results from LES.