Flow-Tagging Velocimetry for Hypersonic Flows Using Fluorescence of Nitric Oxide

Danehy, Paul M.; Frank, A. I.; Houwing, P.; Fox, J.S.; Smith, Daniel R.

doi:10.2514/2.1939

Cited by 119 publications

(25 citation statements)

References 31 publications

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“…In cases where the NO fluorescence lifetime is long relative to fluid displacement, MTV can be used to obtain streamwise velocity maps writing a set of vertical NO excitation lines onto the flowfield with the PLIF lasers [26,27]. The laser sheet is directed through an array of 10 300-mm-focal-length 2-mm-wide microcylindrical lenses, following the approach reported by Lahr et al [20] and Ribarov et al [28].…”

Section: B Spatial Characterizationmentioning

confidence: 99%

Repetitively Pulsed Hypersonic Flow Apparatus for Diagnostic Development

et al. 2012

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A repetitively pulsed hypersonic test facility has been constructed and characterized. This apparatus was designed to enable advanced laser diagnostic development. The underlying principle is to synchronize the intermittent tunnel operation with the laser pulses to achieve effectively continuous operation. Repetitively pulsed (2-20 ms pulse lengths) uniform supersonic flow at Mach 4.6 and hypersonic flow at Mach 6.2 were demonstrated for extended operation. The nozzle flows were characterized using fast-response pressure sensors and NO planar laser-induced fluorescence imaging for two-dimensional temperature and velocity measurements. The pulse-to-pulse impact pressure repeatability was within 1.0%, corresponding to exit flow velocity and temperature fluctuations of 0.7 and 1.0%, respectively. The apparatus can operate over a unit Reynolds number range of 6:0 10 4 to 3:0 10 6 m 1 . Nomenclature

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Section: B Spatial Characterizationmentioning

confidence: 99%

Repetitively Pulsed Hypersonic Flow Apparatus for Diagnostic Development

et al. 2012

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“…In environments in which the tag fluorescence or phosphorescence is rapidly quenched (e.g., oxygen containing gas at atmospheric pressure), MTV methods require a two-step process in which one laser "writes" a tag line (usually via dissociation) and a second laser "reads" the displaced tag line (usually a photo-product from the write phase) [7,8]. For low quenching environments (e.g., low pressure or pure nitrogen at atmospheric pressure), the tag line fluorescence or phosphorescence can persist long enough to record the tag line movement without a second laser [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…MTV can be accomplished by direct seeding of the gas using biacetyl [9], N 2 O [11], NO 2 [12], NO [10,13], tert-butyl nitrate [14], and other molecular seeds [15][16][17]. However, these seeds can be expensive, toxic, damaging to the experimental apparatus, or not viable in reacting flows.…”

Section: Introductionmentioning

confidence: 99%

Vibrationally excited hydroxyl tagging velocimetry

Grady

Pitz

2014

Appl. Opt.

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A new molecular-based velocity method is developed for high-temperature flame gases based on the hydroxyl tagging velocimetry (HTV) technique. In vibrationally excited HTV (VE-HTV), two photons from a KrF laser (248 nm) dissociate H₂O into a tag line of vibrationally excited OH (v=1). The excited state OH tag is selectively detected in a background of naturally occurring ground state OH (v=0). In atmospheric pressure laboratory burners, the OH (v=1) tag persists for 5-10 μs, allowing single-shot velocity measurements along a 2 cm line under lean, stoichiometric, and rich flame conditions with temperatures reaching 2300 K. Mean velocity measurements are demonstrated in a lean (ϕ=0.78) premixed H₂/air turbulent flame (Re=26,550) laboratory flame. The VE-HTV method is best suited to measure high-speed velocities in hot combustion environments in the presence of background OH.

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“…Nitric oxide is a very stable MTV tag that has been used in both low-and high-temperature gas flows [23][24][25][26][27][28][29][30][31]. In low-pressure high-speed flows, NO can be naturally present (e.g., arc-heated tunnel) or directly added to the gas.…”

Section: Introductionmentioning

confidence: 99%

“…In low-pressure high-speed flows, NO can be naturally present (e.g., arc-heated tunnel) or directly added to the gas. When the NO is electronically excited along a line in this low quenching rate environment, the NO fluorescence lifetime is sufficient for the laser line displacement to be tracked in time [23][24][25]. In air flow without NO addition, a highly focused ArF laser beam can create photochemically produced NO along line [26].…”

Section: Introductionmentioning

confidence: 99%

N2O molecular tagging velocimetry

Elbaz

Pitz

2012

Appl. Phys. B

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A new seeded velocity measurement technique, N 2 O molecular tagging velocimetry (MTV), is developed to measure velocity in wind tunnels by photochemically creating an NO tag line. Nitrous oxide "laughing gas" is seeded into the air flow. A 193 nm ArF excimer laser dissociates the N 2 O to O( 1 D) that subsequently reacts with N 2 O to form NO. O 2 fluorescence induced by the ArF laser "writes" the original position of the NO line. After a time delay, the shifted NO line is "read" by a 226-nm laser sheet and the velocity is determined by time-of-flight. At standard atmospheric conditions with 4% N 2 O in air, ∼1000 ppm of NO is photochemically created in an air jet based on experiment and simulation. Chemical kinetic simulations predict 800-1200 ppm of NO for 190-750 K at 1 atm and 850-1000 ppm of NO for 0.25-1 atm at 190 K. Decreasing the gas pressure (or increasing the temperature) increases the NO ppm level. The presence of humid air has no significant effect on NO formation. The very short NO formation time (<10 ns) makes the N 2 O MTV method amenable to low-and highspeed air flow measurements. The N 2 O MTV technique is demonstrated in air jet to measure its velocity profile. The N 2 O MTV method should work in other gas flows as well (e.g., helium) since the NO tag line is created by chemical reaction of N 2 O with O( 1 D) from N 2 O photodissociation and thus does not depend on the bulk gas composition.

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Flow-Tagging Velocimetry for Hypersonic Flows Using Fluorescence of Nitric Oxide

Abstract: We investigate a new type of flow-tagging velocimetry technique for hypersonic flows.

Cited by 119 publications

References 31 publications

Repetitively Pulsed Hypersonic Flow Apparatus for Diagnostic Development

Repetitively Pulsed Hypersonic Flow Apparatus for Diagnostic Development

Vibrationally excited hydroxyl tagging velocimetry

N2O molecular tagging velocimetry

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