Mass Flux Sensing via Tunable Diode Laser Absorption of Water Vapor

Chang, Leyen S.; Jeffries, Jay B.; Hanson, Ronald K.

doi:10.2514/1.j050544

Cited by 23 publications

(22 citation statements)

References 24 publications

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“…This sensor was demonstrated recently in a high-uniformity, low-speed tunnel to accurately measure velocities within 0:5 m=s of the facility set point [8]. In an earlier study, with an O 2 sensor, Lyle et al [6] demonstrated that at low velocities, the distortion to the detected lineshape caused by boundary layers is nearly negligible.…”

Section: Simulation Of Path-integrated Wms Linementioning

confidence: 99%

“…As described in [8], the 1f-normalized WMS-2f signal (WMS2f=1f) enables rejection of non-absorption-related transmission fluctuations and also improves velocity resolution. This sensor was demonstrated recently in a high-uniformity, low-speed tunnel to accurately measure velocities within 0:5 m=s of the facility set point [8].…”

Section: Simulation Of Path-integrated Wms Linementioning

confidence: 99%

“…A brief introduction to WMS theory is now given; nomenclature will follow [8][9][10][11]. The injection current of the diode laser is driven with a high-frequency sinusoid superimposed on a lower-frequency wavelength scan.…”

Section: Simulation Of Path-integrated Wms Linementioning

confidence: 99%

“…Subsequent TDL mass-flux sensors have been deployed for a variety of field tests, including a commercial turbofan (PW6000) inlet at Pratt and Whitney [6], a full-scale Pratt & Whitney F-100 engine in an open ground-test stand at the NASA Dryden Flight Research Facility [7], and a model scramjet combustor at WrightPatterson Air Force Base [3]. A TDLAS sensor employing wavelength-modulation spectroscopy (WMS) for measurement of mass flux using water vapor absorption was previously tested in a subsonic tunnel with uniform flow [8]. Optimization of this sensor for high-enthalpy flows is discussed here.…”

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confidence: 99%

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Supersonic Mass-Flux Measurements via Tunable Diode Laser Absorption and Nonuniform Flow Modeling

Chang¹,

Strand²,

Jeffries³

et al. 2011

AIAA Journal

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Measurements of mass flux are obtained in a vitiated supersonic ground-test facility using a sensor based on lineof-sight diode laser absorption of water vapor. Mass flux is determined from the product of measured velocity and density. The relative Doppler shift of an absorption transition for beams directed upstream and downstream in the flow is used to measure velocity. Temperature is determined from the ratio of absorption signals of two transitions ( 1 1349 nm and 2 1341:5 nm) and is coupled with a facility pressure measurement to obtain density. The sensor exploits wavelength-modulation spectroscopy with second-harmonic detection for large signal-to-noise ratios and normalization with the 1f signal for rejection of non-absorption-related transmission fluctuations. The sensor line of sight is translated both vertically and horizontally across the test section for spatially resolved measurements. Time-resolved measurements of mass flux are used to assess the stability of flow conditions produced by the facility. Measurements of mass flux are within 1.5% of the value obtained using a facility predictive code. The distortion of the wavelength-modulation spectroscopy lineshape caused by boundary layers along the laser line of sight is examined and the subsequent effect on the measured velocity is discussed. A method for correcting measured velocities for flow nonuniformities is introduced and application of this correction brings measured velocities within 4 m=s of the predicted value in a 1630 m=s flow.

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Section: Simulation Of Path-integrated Wms Linementioning

confidence: 99%

Section: Simulation Of Path-integrated Wms Linementioning

confidence: 99%

Section: Simulation Of Path-integrated Wms Linementioning

confidence: 99%

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confidence: 99%

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Supersonic Mass-Flux Measurements via Tunable Diode Laser Absorption and Nonuniform Flow Modeling

Chang¹,

Strand²,

Jeffries³

et al. 2011

AIAA Journal

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“…Most of the applications of diode laser absorption spectroscopy in engines, as opposed to wind-tunnel models, have used water vapor as the absorbing species and distributed feedback diode lasers as the light source (Griffiths and Houwing 2005, Upschulte et al 2000, Zhao et al 2003, Chang et al 2010). However, these tests tended to concentrate on the combustor behavior of the engine, where water vapor is produced in large quantities by the combustion processes.…”

Section: Summary Of Previous Researchmentioning

confidence: 99%

Diode Laser Sensor for Scramjet Inlets

O’Byrne¹,

Wittig²,

Kurtz³

et al. 2011

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Report Documentation PageForm Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. REPORT DATE JUN 20112. REPORT TYPE This work presents test results of a diode-laser sensor for an axially symmetric inlet in a Mach 6 hypersonic flow facility. The conical inlet design presented here is more realistic than the flat plate design presented in the previous report, and is similar to the design that will be chosen as part of the Australian Space Research Program SCRAMSPACE flight test scheduled for 2012. The optical system was changed for this study to make the pitch and catch optics less sensitive to vibration, and to fit into a smaller volume than for the previous test. In addition, wavelength modulation detection was attempted with the system. Initial tests of the conical inlet design showed that it was not starting, as indicated using flow visualization images. The second version of the sensor has similar velocity sensitivity to the system used for the flat plate inlet test. The conical system was, however, still too susceptible to amplitude noise, which hinders the ability of the system to measure the free stream temperature or the angle of attack. Electrical problems with the log-ratio amplifier prevented temperature measurements for the vehicle. Preliminary vibration tests have shown that the problem is caused by independent motion between the laser and collimator when the tunnel fires. A preliminary design of a low-power lock-in amplifier for use in field experiments was completed, and tests with current inputs in place of photodiodes proved successful. SUBJECT TERMS

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Apodized 2f/1f wavelength modulation spectroscopy method for calibration-free trace detection of carbon monoxide in the near-infrared region: theory and experiment

Salati

Khorsandi

2013

Appl. Phys. B

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Mass Flux Sensing via Tunable Diode Laser Absorption of Water Vapor

Cited by 23 publications

References 24 publications

Supersonic Mass-Flux Measurements via Tunable Diode Laser Absorption and Nonuniform Flow Modeling

Supersonic Mass-Flux Measurements via Tunable Diode Laser Absorption and Nonuniform Flow Modeling

Diode Laser Sensor for Scramjet Inlets

Apodized 2f/1f wavelength modulation spectroscopy method for calibration-free trace detection of carbon monoxide in the near-infrared region: theory and experiment

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