Comparison of X-ray and optical measurements in the near-field of an optically dense coaxial air-assisted atomizer

Journal Article · 12 January 2020 · International Journal of Multiphase Flow

DOI: https://doi.org/10.1016/j.ijmultiphaseflow.2020.103219 · OSTI ID:1663381

Bothell, Julie K. ^[1]; Machicoane, Nathanael ^[2]; Li, Danyu ^[1]; Morgan, Timothy B. ^[1]; Aliseda, Alberto ^[2]; Kastengren, Alan L. ^[3]; Heindel, Theodore J. ^[1]

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1. Iowa State Univ., Ames, IA (United States)
2. Univ. of Washington, Seattle, WA (United States)
3. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)

Understanding the near-field region of a spray is integral to optimization and control efforts because this region is where liquid break-up and spray formation occurs, setting the conditions under which the spray dynamics evolve under the gas turbulence and droplet inertia. However, the high optical density of this region complicates measurements; thus, it is not yet well characterized. This paper is intended to compare four of the leading experimental techniques that are being used or developed to study the near-field region of a spray. These techniques are shadowgraphy, tube source X-ray radiography, high-speed synchrotron white-beam X-ray imaging, and synchrotron focused-beam X-ray radiography. Each of these methods is applied to a canonical spray, using the same nozzle, under identical flow conditions. Synchrotron focused-beam radiography shows that a time-averaged Gaussian liquid distribution is a valid approximation very near the nozzle, before the core has broken apart. The Gaussian behavior continues as the spray progresses further downstream, showing self-similarity. A spray angle can be defined from the linear spreading of the Gaussian intensity distribution with downstream distance. The spray angle found from shadowgraphy is validated with focused-beam testing. Finally, a novel method of estimating the intact length of the spray from different X-ray techniques, that uses broadband illumination, is presented.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: US Department of the Navy, Office of Naval Research (ONR); USDOE
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1663381
• Journal Information: International Journal of Multiphase Flow, Journal Name: International Journal of Multiphase Flow Vol. 125; ISSN 0301-9322
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English