Review of Fluorescence-Based Velocimetry Techniques to Study High-Speed Compressible Flows

Bathel, Brett F.; Johansen, Craig T.; Inman, Jennifer A.; Jones, Stephen B.; Danehy, Paul M.

doi:10.2514/6.2013-339

Cited by 5 publications

(1 citation statement)

References 21 publications

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“…Figure 3 shows a schematic of the paths of the forward (solid) and return (dashed) laser beams inside the test section. The use of the delay line allowed for Doppler-based velocimetry measurements in subsequent tests, the results of which are reported elsewhere [11]. Figure 1 (right) shows a side-view schematic of the HYMETS facility and the NO/O-atom imaging system.…”

Section: Experimental Methodsmentioning

confidence: 98%

Simultaneous Nitric Oxide/Atomic Oxygen Laser-Induced Fluorescence in an Arcjet Facility

Johansen¹,

Lincoln²,

Bathel³

et al. 2016

Journal of Thermophysics and Heat Transfer

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Simultaneous nitric-oxide and atomic-oxygen laser-induced-fluorescence experiments were performed in the Hypersonic Materials Environmental Test System facility at the NASA Langley Research Center. The data serve as an experimental database for validation for chemical and thermal nonequilibrium models used in hypersonic flows. Measurements were taken over a wide range of stagnation enthalpies (6.7−18.5 MJ∕kg) using an Earth atmosphere simulant with a composition of 75% nitrogen, 20% oxygen, and 5% argon (by volume). These are the first simultaneous measurements of nitric-oxide and atomic-oxygen laser-induced fluorescence to be reported in literature for the Hypersonic Materials Environmental Test System facility. The maximum atomic-oxygen laser-inducedfluorescence mean signal intensity was observed at a stagnation enthalpy of approximately 12 MJ∕kg, whereas the maximum nitric-oxide laser-induced-fluorescence mean signal intensity was observed at a stagnation enthalpy of 6.7 MJ∕kg. The experimental results were compared to a fluorescence model that assumes equilibrium conditions in the plenum and frozen chemistry in an isentropic nozzle expansion (Mach 5). The equilibrium calculations were performed using CANTERA v2.1.1 with 16 species. The fluorescence model captured the correlation in mean atomicoxygen laser-induced-fluorescence and nitric-oxide laser-induced-fluorescence signal intensities over a large range of stagnation enthalpies tested. The agreement between equilibrium calculations and the experimental laser-induced fluorescence signals was better for nitric oxide than atomic oxygen. Very weak correlations between single-shot atomic-oxygen laser-induced-fluorescence and nitric-oxide laser-induced-fluorescence intensities were observed in the experiments at all of the stagnation enthalpy conditions. It was found that the overall magnitude of nitric-oxide laser-induced-fluorescence fluctuations was much larger than atomic-oxygen laser-induced-fluorescence fluctuations.

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Section: Experimental Methodsmentioning

confidence: 98%

Simultaneous Nitric Oxide/Atomic Oxygen Laser-Induced Fluorescence in an Arcjet Facility

Johansen¹,

Lincoln²,

Bathel³

et al. 2016

Journal of Thermophysics and Heat Transfer

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Doppler velocimeter based on dual-comb absorption spectroscopy

Gu¹,

Zou²,

Zuo³

et al. 2020

Photon. Res.

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The determination of airflow parameters is essential to the research of critical information on environment monitoring, chemical kinetics, and aerodynamic and propulsion applications. During the past few decades, tunable diode laser absorption spectroscopy has become a common and efficient tool for the flow velocity measurement based on the Doppler shift of the absorption line. Dual-comb absorption spectroscopy (DCAS), as a state-of-the-art Fourier-transform broadband spectroscopic technique, not only can detect multiple trace molecules in parallel but also can extract Doppler shifts to derive the flow velocity through the analysis of dozens of molecular absorption lines simultaneously with high precision. Here, we report a proof-of-principle demonstration of the velocity measurements of acetylene at various flow velocities by means of a high-resolution and broadband DCAS. Mode-resolved Doppler-shifted rotational-vibrational lines in the P branch of acetylene molecules are obtained. A model for multiline Doppler frequency determination is investigated and experimentally verified. The flow velocity measurements with a measuring uncertainty down to the submeter per second over the range from 8.7 m/s to 44.8 m/s at an effective time resolution of 1 s and a measuring uncertainty of 1.97 m/s at 0.1 s are demonstrated. With broadband mid-infrared frequency combs covering atmospheric transmission windows, the open-path measurement for monitoring diffusion of the weak pollutant source would be realized.

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Molecular-Based Optical Diagnostics for Hypersonic Nonequilibrium Flows

Danehy¹,

Bathel²,

Johansen³

et al. 2015

Hypersonic Nonequilibrium Flows: Fundamentals and Recent Advances

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Outline for 1 st Talk • Temperature, equilibrium and nonequilibrium • Characteristics of hypersonic nonequilibrium flow -What needs measuring? Explanation of Parameter Charts Overview:This appendix shows the static conditions (temperature and pressure) at which various measurement techniques have been successfully demonstrated. When planning a new experiment to occur at a specified temperature and pressure, these graphs might be useful to see what measurements have previously been demonstrated at those conditions. The numerals used as data points indicate the reference in the attached reference list. The different measurement techniques are denoted by the colors indicated. Pressure is plotted on a logarithmic axis while temperature is on a linear axis. Caveats:• The data includes both references contained in the manuscript as well as additional works.• The reference numbers in the manuscript are different from those in this appendix.• This study is not meant to be exhaustive; it provides a partial sampling of the data available in the literature. • Some data points overlap. This is particularly true at room temperature and atmospheric pressure. Some data has been omitted to avoid overlaps.

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Review of Fluorescence-Based Velocimetry Techniques to Study High-Speed Compressible Flows

Cited by 5 publications

References 21 publications

Simultaneous Nitric Oxide/Atomic Oxygen Laser-Induced Fluorescence in an Arcjet Facility

Simultaneous Nitric Oxide/Atomic Oxygen Laser-Induced Fluorescence in an Arcjet Facility

Doppler velocimeter based on dual-comb absorption spectroscopy

Molecular-Based Optical Diagnostics for Hypersonic Nonequilibrium Flows

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