Experimental and computational study of a lifted, non-premixed turbulent free jet flame

Abstract

The results of an experimental and modelling study of a lifted, non-premixed methane turbulent free jet flame issuing into still air are presented. Detailed in-flame measurements, including the gas temperature, oxygen and NO concentration distributions, are made. In a parallel computational study, a radiative mixedness–reactedness flamelet combustion model is employed to simulate the experimental flame. A comprehensive radiation heat transfer model based on the discrete transfer method of solution of the radiative transport equation, together with the wide-band model for gas absorption coefficients, was used. The NO formation and emission was also calculated using a post-processing approach. Validation of the numerical results against the experimental data shows generally good quality combustion predictions in the near burner region. However, predictive difficulties are encountered in the downstream region, particularly for the oxygen concentration. The NO predictions reveal discrepancies when compared with measurements in the fuel rich part of the flame. The in-flame experimental data, with the aid of the predictions, has provided an enhanced understanding of combustion and NO characteristics of the lifted, non-premixed turbulent free jet flame.