Measurements of gas temperature and velocity in hypervelocity flows using diode-laser sensors

Wehe, Shawn; Baer, Douglas S.; Hanson, Ronald K.; Chadwick, Kenneth

doi:10.2514/6.1998-2699

Cited by 23 publications

(11 citation statements)

References 9 publications

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“…The mixing of driver gas into the test gas in reflected shock tunnels is a well-known phenomenon, occurring due to boundary-layer "jetting" as the reflected shock propagates through the shock tube. 19,20 While driver gas does not affect the gas-dynamic flow properties in this facility due to the similarity of the driver γ with that of the test gas, 18 the presence of driver gas in the test gas will alter combustion chemistry and thus this TDLAS measurement of the driver gas concentration provides an important input for modelers attempting to compare their results with facility measurements. Previous measurements at these conditions have estimated that driver gas did not appear in the test gas until approximately 3.5 ms after the arrival of the test gas.…”

Section: Ivb Non-combusting Mixing Testmentioning

confidence: 99%

Hypersonic scramjet testing via TDLAS measurements of temperature and column density in a reflected shock tunnel

Schultz

Goldenstein

Strand

et al. 2014

52nd Aerospace Sciences Meeting

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A wavelength-multiplexed two-color TDLAS sensor probing transitions near 1.4 µm was developed to measure H2O temperature and column density simultaneously across three lines-of-sight in a ground-based model scramjet combustor. High-enthalpy scramjet conditions equivalent to Mach 10 flight were generated with a reflected shock tunnel. The sensor hardware development and optical engineering to overcome noisy combustor conditions including short test time, beam steering, and mechanical vibration are discussed. A new scanned wavelength-modulation spectroscopy (WMS) technique was used to acquire the complete spectral lineshape while maintaining the high signal-to-noise ratio characteristic of WMS measurements. Two combusting flow experiments were conducted and the results compared with steady-state CFD calculations, with both the simulations and the measurements finding formation of H2O from H2 combustion during the test time. To our knowledge, this work represents the first use of WMS in a reflected shock tunnel and the first use of scanned-WMS in a scramjet combustor. Nomenclature I 0 = incident spectral intensity, W/cm 2 s −1 I t = transmitted spectral intensity, W/cm 2 s −1 ν = optical frequency, cm −1 α = absorbance L = optical path length, cm n i = number density of absorbing species, molecules/cm 3 S n = transition linestrength, cm −1 /molecule cm −2 φ = lineshape function T = temperature, K P = pressure, atm χ = gas mole fraction vector χ i = gas mole fraction of species i A = integrated absorbance, cm −1 N i = column density, molecules/cm −2 σ i = column density (mass basis), kg/cm −2 ρ i = density of absorbing species i, kg/m −3 Q = partition function of absorption transition AIAA SciTech h = Planck constant, J·s c = speed of light, cm/s E = lower state energy of absorption transition, cm −1 k = Boltzmann constant, J/K ν 0 = line-center frequency of absorption transition, cm −1 I 0 = average laser intensity, W/cm 2 s −1 i n = intensity sinusoid amplitude (n=1, 2) ψ n = intensity sinusoid phase shifts (n=1, 2) ν = laser center frequency, cm −1 a n = wavelength scan and modulation depths (n=1, 2) Ψ n = wavelength sinusoid phase shifts (n=1, 2) f s = laser scan frequency, Hz f m = laser modulation frequency, Hz Φ = fuel-air equivalence ratio θ = angle of attack γ = heat capacity ratio c P /c V

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Section: Ivb Non-combusting Mixing Testmentioning

confidence: 99%

Hypersonic scramjet testing via TDLAS measurements of temperature and column density in a reflected shock tunnel

Schultz

Goldenstein

Strand

et al. 2014

52nd Aerospace Sciences Meeting

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“…The need to characterize combustion systems with limited optical access has driven the development of numerous compact LAS sensors [239,240,42,241,242,158,164,243,183,244,245,246,154,247] and the majority of these sensors have leveraged robust 1920 telecommunication-grade optical hardware. Specifically, Wehe et al [239,240] embedded a diode-laserbased sensor into a probe for gas temperature, velocity, and H 2 O in hypervelocity flows, Schultz et al [243] and Strand and Hanson [244] developed fiber-1925 coupled sensor packages for model scramjets housed in vacuum chambers, Ebert et al [247] and Whitney et al [158] developed compact arrangements for providing line-of-sight access in IC engines, and Caswell…”

Section: Compact Sensors 1915mentioning

confidence: 99%

Infrared laser-absorption sensing for combustion gases

Goldenstein

Spearrin

Jeffries

et al. 2017

Progress in Energy and Combustion Science

525

197

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Infrared laser-absorption spectroscopy (IR-LAS) sensors play an important role in diagnosing and characterizing a wide range of combustion systems. Of all the laser-diagnostic techniques, LAS is arguably the most versatile and quantitative, as it has been used extensively to provide quantitative, species-specific measurements of gas temperature, pressure, composition and velocity in both laboratory-and industrial-scale systems. Historically, most IR-LAS work has been conducted using tunable diode lasers, however, today's researchers have access to a wide range of light sources that provide unique sensing capabilities and convenient access to nearly the entire IR spectrum (≈1 to 20 μm). In particular, the advent of room-temperature wavelength-tunable mid-infrared semiconductor lasers (e.g., interband-and quantum-cascade lasers) and hyperspectral light sources (e.g., Fourierdomain mode-locked lasers, dispersed supercontinuum lasers, and frequency combs) has provided a number of unique capabilities that combustion researchers have exploited. The primary goal of this review paper is to document the recent development, application, and current capabilities of IR-LAS sensors for laboratory-and industrial-scale combustors and propulsion systems. A thorough review and description of the fundamental spectroscopy governing the accuracy of such sensors, and recent findings and databases that enable improved modeling of molecular absorption spectra will be provided. Modern light sources and the most commonly used diagnostic techniques are also discussed.

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“…NO number density measurements by UV absorption and NO PLIF have also been reported in the HYPULSE facility [7]. Several diagnostic advances have also been reported in studies at the Calspan University at Buffalo Research Center (CUBRC) LENS I and LENS II Hypersonic Shock Tunnels, including temperature and velocity by water vapor-based diode laser absorption [8], NO number density, temperature and velocity by NObased diode laser absorption [9,10], and aero-optic distortion by Phase Shift Interferometry, infrared scene generation and recording techniques [11,12]. Finally, Barker et al have reported a novel flow tagging velocimetry diagnostic for use in high enthalpy short-duration facilities based on laser enhanced ionization of atomic sodium [13], Allen, et al have reported single laser pulse NO PLIF based thermometry in a high enthalpy shock tunnel facility located at PSI corporation [14], and McMillan et al have reported two-line NO PLIF temperature imaging of in a transverse jet in a supersonic cross flow [15].…”

Section: Introductionmentioning

confidence: 95%

NO PLIF Imaging in the CUBRC 48" Shock Tunnel

Jiang

Bruzzese

Patton

et al. 2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Nitric Oxide Planar Laser-Induced Fluorescence (NO PLIF) imaging is demonstrated at a 10 kHz repetition rate in the Calspan-University at Buffalo Research Center's (CUBRC) 48-inch Mach 9 hypervelocity shock tunnel using a pulse burst laser-based high frame rate imaging system. Sequences of up to ten images are obtained internal to a supersonic combustor model, located within the shock tunnel, during a single ~10-millisecond duration run of the ground test facility. This represents over an order of magnitude improvement in data rate from previous PLIF-based diagnostic approaches. Comparison with a preliminary CFD simulation shows good overall qualitative agreement between the prediction of the mean NO density field and the observed PLIF image intensity, averaged over forty individual images obtained during several facility runs.

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Measurements of gas temperature and velocity in hypervelocity flows using diode-laser sensors

Cited by 23 publications

References 9 publications

Hypersonic scramjet testing via TDLAS measurements of temperature and column density in a reflected shock tunnel

Hypersonic scramjet testing via TDLAS measurements of temperature and column density in a reflected shock tunnel

Infrared laser-absorption sensing for combustion gases

NO PLIF Imaging in the CUBRC 48" Shock Tunnel

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