Effect of Inlet Mixture Stratification on Bluff-Body Stabilized, Turbulent, Prevaporized n-Heptane-Air Flames

An investigation of the characteristics of turbulent prevaporized n-heptane-air flames, stabilized in the downstream wake region of a stratifier/bluff-body combustor configuration under the effect of inlet fuel-air mixture stratification and preheat, is presented. Experimental and computational results for different fuel-air mixing wake topologies have been obtained by regulating the fuel injection level and the incoming fuel-air ratio gradient. Fourier transform infrared analysis and particle image velocimetry measurements were taken to assess the mixing field characteristics in the near-wake region under nonreacting operation. Chemiluminescence measurements were also obtained to assess the flame topology under reacting conditions. In the computations, an implicit, finite-volume-based large eddy simulation method, coupled with a 25-species reduced n-C7H16 kinetic scheme, was utilized for reproducing the mixing and the reacting field characteristics. (C) 2021 American Society of Civil Engineers.