Chemiluminescence and Structure Characteristics in CH4/O2 Coflow Jet Diffusion Flames

The chemiluminescence characteristics of the excited state radicals are significant for spectrum-based diagnostics of practical diffusion flames. The detailed spatial profiles of OH* and CH* radicals in diffusion flames are investigated, and the effects of different conditions on the chemiluminescence and structure are studied. OH* emissions are obtained by the UV imaging system, while CH* emissions are captured by a novel high-spatial-resolution line-scan hyperspectral camera. The results show that there are three structure types in laminar flame along the flame propagating direction: jet core region, jet transition region and the jet fully developed region. However, the turbulent flame only has jet core region and transition region. Moreover, the twodimensional distributions of OH* and CH* under different equivalent ratios ([O/C](e)) also feature different characteristics. (C) 2017 The Authors. Published by Elsevier Ltd.