Velocity and temperature measurement in supersonic free jets using spectrally resolved Rayleigh scattering

Panda, Jayanta; Seasholtz, Richard G.

doi:10.2514/6.1999-296

Cited by 36 publications

(43 citation statements)

References 13 publications

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“…However, when the gas leaves the pipe and expands, it is diluted with surrounding air and quickly reaches ambient temperature. This initial expansion to ambient temperature created a cloud with an estimated volume of 125 m 3 using empirical models [2,3].…”

Section: Incident Review and Emission Calculationsmentioning

confidence: 99%

Accident reconstruction and plume modeling of an unplanned ammonia release

Daly¹,

Zannetti²,

Jennings³

2013

WIT Transactions on Ecology and the Environment

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This paper describes the study we performed in relation to an accidental release of ammonia at a plant in Luling, Louisiana. Our work involved the understanding of the dynamics of the accident, the evaluation of the emission scenario, the computer modeling of the ammonia plume transported by the wind, and the visualization of our results for the purpose of litigation support and presentation to a non-technical audience. The emission scenario was complicated because of a high-velocity jet release and stormy weather conditions. We used emissions and weather data available at the site, in addition to other local weather data. We also used an EPA-approved model to simulate the transport and dispersion of the ammonia cloud and calculate ground-level concentrations of ammonia over the period of concern (a 2-hour interval). We concluded that maximum hourly concentrations of ammonia, beyond the industrial fenceline in the local community, were around 0.20 ppm, which is far below existing levels of concern. However, our odor modeling calculations showed that short-term concentrations were potentially larger, and may have reached 5 ppm for very short periods. Our estimated concentrations of ammonia were validated by the locations and times of local odor complaints as well as in-situ measurements. Finally, we visualized the plume by applying a simplified version of our MONTECARLO particle model and creating a computer animation of plume concentrations, in order to illustrate the dynamics of the events to a non-technical audience.

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Section: Incident Review and Emission Calculationsmentioning

confidence: 99%

Accident reconstruction and plume modeling of an unplanned ammonia release

Daly¹,

Zannetti²,

Jennings³

2013

WIT Transactions on Ecology and the Environment

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“…Previous works using molecular Rayleigh scattering to make temperature, velocity, and number density measurements in various environments (Lock et al 1992, Panda & Seasholtz 1999, Mielke et al 2005, and dynamic density and velocity measurements in supersonic free jets (Seasholtz et al 2002) have been reported. The technique described in this paper has been demonstrated previously in various lab-scale flow studies and validated by comparison with hotwire and coldwire probe measurements (Mielke 2008).…”

Section: Introductionmentioning

confidence: 99%

Dynamic measurement of temperature, velocity, and density in hot jets using Rayleigh scattering

Mielke

Elam

2009

Exp Fluids

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A molecular Rayleigh scattering technique was utilized to measure time-resolved gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz. A high power continuous-wave (cw) laser beam was focused at a point in an air flow field and Rayleigh scattered light was collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultipler tubes operated in the photon counting mode allowed high frequency sampling of the total signal level and the circular interference pattern to provide time-resolved density, temperature, and velocity measurements. Mean and rms velocity and temperature, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at the NASA Glenn Research Center (GRC). The Rayleigh measurements are compared with particle image velocimetry data and CFD predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.

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“…Previous works using molecular Rayleigh scattering to make temperature, velocity, and number density measurements in harsh environments [12][13][14][15], and dynamic density and velocity measurements in supersonic free jets [16,17] have been reported. The current work describes further development and validation of a technique previously reported in [18] and [19] in which dynamic temperature, velocity, and density measurements were made in a low speed heated jet and an acoustically driven flow up to 16 kHz.…”

mentioning

confidence: 99%