CH and NO planar laser-induced fluorescence and rayleigh-scattering in turbulent flames using a multimode optical parametric oscillator

Miller JD, Tröger JW, Engel S, Seeger T, Leipertz A, Meyer TR (2021)


Publication Type: Journal article

Publication year: 2021

Journal

Book Volume: 60

Pages Range: 98-108

Journal Issue: 1

DOI: 10.1364/AO.406237

Abstract

An optical parametric oscillator (OPO) is developed and characterized for the simultaneous generation of ultraviolet (UV) and near-UV nanosecond laser pulses for the single-shot Rayleigh scattering and planar laser-induced-fluorescence (PLIF) imaging of methylidyne (CH) and nitric oxide (NO) in turbulent flames. The OPO is pumped by a multichannel, 8-pulse Nd:YAG laser cluster that produces up to 225 mJ/pulse at 355 nm with pulse spacing of 100 µs. The pulsed OPO has a conversion efficiency of 9.6% to the signal wavelength of ∼430 nm when pumped by the multimode laser. Second harmonic conversion of the signal, with 3.8% efficiency, is used for the electronic excitation of the A-X (1,0) band of NO at ∼215 nm, while the residual signal at 430 nm is used for direct excitation of the A-X (0,0) band of the CH radical and elastic Rayleigh scattering. The section of the OPO signal wavelength for simultaneous CH and NO PLIF imaging is performed with consideration of the pulse energy, interference from the reactant and product species, and the fluorescence signal intensity. The excitation wavelengths of 430.7 nm and 215.35 nm are studied in a laminar, premixed CH4−H2−NH3–air flame. Single-shot CH and NO PLIF and Rayleigh scatter imaging is demonstrated in a turbulent CH4−H2−NH3 diffusion flame using a high-speed intensified CMOS camera. Analysis of the complementary Rayleigh scattering and CH and NO PLIF enables identification and quantification of the high-temperature flame layers, the combustion product zones, and the fuel-jet core. Considerations for extension to simultaneous, 10-kHz-rate acquisition are discussed.

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How to cite

APA:

Miller, J.D., Tröger, J.W., Engel, S., Seeger, T., Leipertz, A., & Meyer, T.R. (2021). CH and NO planar laser-induced fluorescence and rayleigh-scattering in turbulent flames using a multimode optical parametric oscillator. Applied Optics, 60(1), 98-108. https://doi.org/10.1364/AO.406237

MLA:

Miller, Joseph D., et al. "CH and NO planar laser-induced fluorescence and rayleigh-scattering in turbulent flames using a multimode optical parametric oscillator." Applied Optics 60.1 (2021): 98-108.

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