Key modeling issues in prediction of minor species in diluted-preheated combustion conditions

A numerical investigation of a jet in hot coflow (JHC) burner emulating Moderate or Intense Low-oxygen Dilution (MILD) combustion is carried out in order to understand key modeling issues for such three stream problem. Favre-averaged Navier–Stokes (FANS) equations were solved in a finite volume scheme with the Eddy Dissipation Concept (EDC) model for the turbulence-chemistry interaction and the skeletal KEE mechanism (consisting 17 species and 58 reactions) for the combustion reactions. It was found that mixing in shear layers has a significant impact on the temperature, species and flow fields and could be predicted only with a proper selection of the turbulence levels at the inlet boundaries. Analyzing the minor species reaction path together with the mean and fluctuating temperature fields elucidated the great influence of temperature fluctuations on the net rate of CO and OH production in MILD combustion regime.