A sheet laser flow visualization system in the NASA Lewis Icing Research Tunnel

Canacci, Victor A.; Bencic, Timothy J.; Krupar, Martin J.; Potapczuk, Mark G.

doi:10.2514/6.1998-342

Cited by 2 publications

(1 citation statement)

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“…Various optical techniques have been applied in NASA GRC's Icing Research Tunnel (IRT) over the years [2][3][4][5] . Building on the knowledge gained from developing and applying various optical techniques in the IRT facility a light extinction tomography system has been targeted as the desired cloud diagnostic for PSL.…”

Section: Introductionmentioning

confidence: 99%

Advanced Optical Diagnostics for Ice Crystal Cloud Measurements in the NASA Glenn Propulsion Systems Laboratory

Bencic

Fagan

Zante

et al. 2013

5th AIAA Atmospheric and Space Environments Conference

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A light extinction tomography technique has been developed to monitor ice water clouds upstream of a direct connected engine in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center (GRC). The system consists of 60 laser diodes with sheet generating optics and 120 detectors mounted around a 36-inch diameter ring. The sources are pulsed sequentially while the detectors acquire line-of-sight extinction data for each laser pulse. Using computed tomography algorithms, the extinction data are analyzed to produce a plot of the relative water content in the measurement plane. To target the low-spatial-frequency nature of ice water clouds, unique tomography algorithms were developed using filtered backprojection methods and direct inversion methods that use Gaussian basis functions. With the availability of a priori knowledge of the mean droplet size and the total water content at some point in the measurement plane, the tomography system can provide near real-time in-situ quantitative full-field total water content data at a measurement plane approximately 5 feet upstream of the engine inlet. Results from ice crystal clouds in the PSL are presented. In addition to the optical tomography technique, laser sheet imaging has also been applied in the PSL to provide planar ice cloud uniformity and relative water content data during facility calibration before the tomography system was available and also as validation data for the tomography system. A comparison between the laser sheet system and light extinction tomography resulting data are also presented. Very good agreement of imaged intensity and water content is demonstrated for both techniques. Also, comparative studies between the two techniques show excellent agreement in calculation of bulk total water content averaged over the center of the pipe.

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Section: Introductionmentioning

confidence: 99%