Filtered Rayleigh scattering mixing measurements of merging and non-merging streamwise vortex interactions in supersonic flow

Ground, Cody R.; Gopal, Vijay; Maddalena, Luca

doi:10.1007/s00348-018-2521-4

Cited by 12 publications

(4 citation statements)

References 30 publications

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“…Early FRS work made use of the signal gain capability offered by intensified CCD (ICCD) cameras due to the relatively weak signal produced by the Rayleigh scattering process [26,63,64,90,91]. Improvements in laser and detector technology have enabled the use of modern unintensified CCDs for FRS [61,92,93], which have much less noise than ICCDs. Another option demonstrated in FRS experiments is the electron-multiplied CCD (EMCCD) [67,94,95].…”

Section: Detectormentioning

confidence: 99%

“…Nevertheless, they were able to demonstrate the feasibility of the technique. This approach was also used by Maddalena et al to quantify the time-averaged mixture composition of supersonic flowfields dominated by streamwise vortices at conditions relevant to scramjet-powered hypersonic flight [45,93,[114][115][116]. In these experiments, helium was injected through a ramped-strut injector to simulate the dynamics of hydrogen fuel.…”

Section: Mixture Compositionmentioning

confidence: 99%

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Quantitative gas property measurements by filtered Rayleigh scattering: a review

Ground¹,

Hunt²,

Hunt³

2023

Meas. Sci. Technol.

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Filtered Rayleigh scattering (FRS) is a laser-based diagnostic technique used to nonintrusively quantify various thermodynamic properties of a light-scattering gas. The backbone of FRS is the molecular filtering of Rayleigh scattered light. This concept was initially introduced by the atmospheric LIDAR community before being adopted within the aerospace research field in the early 1990s. Since then, FRS has matured into a versatile quantitative diagnostic tool and has found use in a variety of flow regimes ranging from sub- to supersonic speeds in both reacting and nonreacting environments. This adoption can be attributed to the wealth of information that can be obtained via FRS, including the gas density, pressure, temperature, velocity, species composition, or, in some cases, several of these properties at once. This article reviews the current state of FRS methodology in recovering such gas properties. As knowledge of the fundamentals of Rayleigh scattering and spectral light filtering is crucial to the design of an FRS experiment, we begin by briefly reviewing these areas. Subsequently, we conduct a survey of experimental design strategies, assumptions, and data reduction methods used to measure different gas properties using FRS. We conclude the review with a short discussion on quantification of experimental uncertainty and future trends in FRS.

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Section: Detectormentioning

confidence: 99%

Section: Mixture Compositionmentioning

confidence: 99%

Quantitative gas property measurements by filtered Rayleigh scattering: a review

Ground¹,

Hunt²,

Hunt³

2023

Meas. Sci. Technol.

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“…FRS imaging has previously been demonstrated at MHz repetition rate using a low energy pulse burst laser (~1 mJ per pulse at 532 nm) [15]. FRS has also been extensively used for quantitative measurements in enclosed combustors, and in flames seeded with particles [16][17][18][19][20]. However, the test case presented here is a particularly challenging one due to proximity to the wall, and small collection angle.…”

Section: Introductionmentioning

confidence: 99%

50-kHz-rate Rayleigh and filtered Rayleigh scattering thermometry using a pulse-burst laser

Krishna

Mahuthannan

Lacoste

et al. 2021

AIAA Scitech 2021 Forum

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A one-dimensional Rayleigh/filtered Rayleigh scattering system is developed using a pulse burst laser and it is used to demonstrate temperature measurements at 50 kHz repetition rate. The system utilizes a CCD camera operated in the subframe burst gating mode for improved signal to noise ratio. This improvement in precision is verified by conducting temperature measurements in a laminar flame and comparing the results with that obtained using a highspeed CMOS camera. Two experiments are conducted to demonstrate the capability of the system. Firstly, 1D Rayleigh thermometry is conducted in a turbulent jet flame with Reynolds number 15200. Time-resolved temperature profiles and spatially resolved integral time scales are presented. After this, we demonstrate a 50-kHz-rate filtered Rayleigh scattering thermometry experiment using the pulse burst laser. In this experiment, the 1D temperature profiles of a turbulent flame propagating through a narrow rectangular channel with a variable height of approximately 2mm is studied. The test facility is designed to study the flame quenching process in narrow channels and has unique measurement challenges due to the limited optical access and short flow duration. Measurements at three heights, ranging from quenching to no quenching conditions, are presented and the evolution of temperature profile is discussed. i = lineshape function of Rayleigh-Brillouin spectrum of species i P = pressure

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“…In combustion diagnostics, the technique has been used prevalently for 2D temperature measurements, and very few works in the past concentrated on the measurement of mole fraction using FRS. Ground et al [31] used FRS to obtain a 2D mapping of helium to air ratio in merging and non-merging streamwise vortices in supersonic flows. The focus was on 2D average flow field, and the 20% single-shot uncertainty was deemed acceptable.…”

Section: Introductionmentioning

confidence: 99%

Mole fraction measurement through a transparent quarl burner using filtered Rayleigh scattering

et al. 2019

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A filtered Rayleigh scattering system is developed and applied to measure the mole fraction of methane in a methane-air swirl flow through a transparent conical quartz quarl. Light scattering from the location where the laser beam is incident on the surface of the quarl is orders of magnitudes larger than Rayleigh scattering from the gas mixture of interest. This diffusive scattering is suppressed using molecular absorption by an iodine cell and using spatial filtering by an optical aperture. Residual stray light accounted for up to 5% of the total signal and had to be removed for accurate measurements. The flow consisted of a non-premixed mixture of methane and air in the central jet surrounded by a strong swirling air flow. Measurements were conducted at a height of 4 mm from the fuel tube's exit for six different conditions of the swirl flow to demonstrate the ability of the instrument to study the effects of swirl strength and fuel flow rate on the mixing process. By using a 4-leg pulse stretcher to allow higher laser energies in the probe volume, large collection optics and a reference iodine cell to monitor laser wavelength variations, standard deviations of ~ 0.006 in air and ~ 0.012 in a laminar methane flow were achieved for mole fraction measurements.

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Filtered Rayleigh scattering mixing measurements of merging and non-merging streamwise vortex interactions in supersonic flow

Cited by 12 publications

References 30 publications

Quantitative gas property measurements by filtered Rayleigh scattering: a review

Quantitative gas property measurements by filtered Rayleigh scattering: a review

50-kHz-rate Rayleigh and filtered Rayleigh scattering thermometry using a pulse-burst laser

Mole fraction measurement through a transparent quarl burner using filtered Rayleigh scattering

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