Journal of Propulsion and Power · 2019 · 11 citations · 26 references
EngineeringChemical EngineeringMechanical EngineeringCombustionFlow VisualizationSpectroscopyCombustion FundamentalsCombustion ProcessesFlame PropagationFlame StructureFluorescence SpectroscopyPremixed FlamesCombustion DynamicsFlame DiagnosticsFlame Structure AnalysisFlame TopologyLaser-induced FluorescencePlanar Laser-induced FluorescencePremixed Flame StructureReaction-zone Structure
Formaldehyde planar laser-induced fluorescence (PLIF) imaging was performed in a premixed, ethylene-fueled dual-mode scramjet combustor to study the flame structure and dynamic flame behavior. PLIF is used as a marker to provide information on the structure and position of the lower-temperature portion of the reaction zone. Low-repetition-rate (10 Hz) measurements were acquired at several cross-flow planes along the axial flow direction. Statistical analysis of the topology indicates sparse concentrations of formaldehyde that are intermittently detected by the PLIF measurement. Comparisons between previous large-eddy simulations, laboratory-scale flames, and the current experimental measurements indicate discrepancies between the expected and measured formaldehyde concentrations and structure. High-speed formaldehyde PLIF also was conducted at 50 kHz to further investigate the intermittency of the formaldehyde layers in the flow.
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