Simultaneous multispecies combustion diagnostics using FRAME

Abstract

continuous drive towards efficient and compact combustion devices has necessitated the exploration of innovative diagnostic methodologies. This study investigates the efficacy and potential of the FRAME (Frequency Recognition Algorithm for Multiple Exposures) technique, inspired by structured illumination, for advanced combustion diagnostics. The technique offers significant capabilities in simultaneous multispectral imaging, offering enhanced insights into combustion phenomena. The research investigates the application of the FRAME technique in simultaneous multispectral imaging of PAH (Polycyclic Aromatic Hydrocarbons)/OH radicals, and soot, employing Laser-Induced Fluorescence (LIF) and Laser-Induced Incandescence (LII) methods. Both symmetric and asymmetric diffusion flames are examined, with the technique extended to facilitate the three-dimensional mapping of flames. This enables tomographic reconstruction and quantitative estimation of soot volume fraction, achieved by scanning the flame with laser sheets spaced 0.5 mm apart. The resulting tomographic reconstruction provides the species distribution within the flame, facilitating comparative analysis. The study scrutinizes four major optical configurations to discern practical limitations and optimal configuration of setups.