4D spatiotemporal evolution of combustion intermediates in turbulent flames using burst-mode volumetric laser-induced fluorescence
Benjamin R. Halls, Naibo Jiang, Terrence R. Meyer, Sukesh Roy, Mikhail N. Slipchenko, and James R. Gord
Index: 10.1364/OL.42.002830
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Abstract
High-speed (20 kHz rate), volumetric laser-induced-fluorescence imaging of combustion intermediates such as a formaldehyde (CH2O) and polycyclic aromatic hydrocarbon (PAH) species is demonstrated for tracking the four-dimensional (4D) evolution of turbulent flames. The third-harmonic, 355 nm output of a burst-mode Nd:YAG laser with a 130 mJ/pulse is expanded to 30 mm diameter for volume illumination of the base region of a methane–hydrogen jet diffusion flame. Eight simultaneous images from different viewing angles are used to collect the resulting fluorescence signal for reconstruction of 200 time-sequential three-dimensional volumes over 10 ms duration. The signal-to-noise ratio (SNR) of 300:1 is achieved after reconstruction with a temporal resolution of 100 ns and spatial resolution of 0.85–1.5 mm.