Transported Probability Density Function Method for MILD Combustion

Abstract

Modeling of Moderate and Intense Low oxygen Dilution (MILD) combustion is a challenging task due to slow reaction rates. The present chapter aims at assessing the predictive capability of transport PDF-based combustion models for two burners (Delft-Jet-in-Hot-Coflow (DJHC) burner and Adelaide JHC burner), which mimics MILD combustion characteristics. In the present work, both the transported PDF approaches, i.e., Lagrangian PDF (LPDF) and multi-environment Eulerian PDF (MEPDF), are considered and assessed. For DJHC burner, both 2D and 3D calculations are reported for varying parameters. However, for Adelaide burner, only 2D computations are reported. In the context of LPDF calculations, different micro-mixing models are considered to investigate the effect of molecular diffusion. In the case of DJHC burner, all the models behave properly and predictions are observed to be in good agreement. However, the model discrepancies are noticed while comparing the species profiles, especially in the case of Adelaide burner. Also, the performance of the models is properly assessed by analyzing the profiles of minor species and RMS of scalar fields. Overall, the performances are improved with increasing O2 content, i.e., higher Damkohler number range.