Hydroxyl-Radical Planar Laser-Induced Fluorescence Imaging of Turbulent Supersonic Combustion

Abstract

Flow visualisation and statistical analysis of a supersonic, turbulent reacting flow from non-intrusive hydroxyl radical (OH) planar laser-induced fluorescence (PLIF) images are presented. The OH PLIF images show instantaneous structures of turbulence in two combustor configurations at different fuel equivalence ratios in the University of Virginia Supersonic Combustion Facility (UVaSCF). Proper orthogonal decomposition (POD) and autocorrelations are performed on the OH PLIF data to extract quantitative information about turbulent fluctuations and length scale correlations. Changes in integral length scales and turbulent energy flow patterns are observed as a function of position in the combustor and fuel equivalence ratio. Dual-mode operation with supersonic and subsonic combustion is demonstrated in the facility. This work has been performed in collaboration with other non-intrusive diagnostic techniques in the UVaSCF to develop a comprehensive database for the validation of computational fluid dynamics (CFD) models.