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Conference Papers Year : 2016

Digital in-line holography for near field observation of liquid-liquid flows under astigmatic conditions

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Abstract

Several processes used in nuclear research and industry are based on liquid-liquid extraction. This method is designed for selective separation of products in a mixture. As the transfer occurs at the contact surface between both phases, the characterization of the dispersed phase of the emulsion (size distribution of droplets, shape, etc.) is fundamental. Numerous imaging techniques can be used to measure, but one of them, digital holography (DH) is particularly relevant as it determines simultaneously the size, shape and 3D positions of particles using a single camera. Because the droplets are millimeter size, a nearfield diffraction regime is observed and adapted numerical solutions are required. In a previous work [1], an effective focusing method has been validated on an experimental cuboid-shape setup designed to produce droplets of known diameter and velocity as well as an unknown polydisperse droplet population. However, the standard shapes of liquid-liquid extraction apparatus are cylindrical, inducing a strong astigmatism and preventing the direct use of classical focusing methods. In this communication, we proposed a survey of two approaches, based respectively on Generalized Huygens-Fresnel Transform (GHFT) and Fractional Fourier Transform (FrFT), which allows overpassing this issue. Using these tools induce a supplementary quadratic phase term, which must be corrected in order to use automatic focalisation methods.
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Dates and versions

cea-02509783 , version 1 (17-03-2020)

Identifiers

  • HAL Id : cea-02509783 , version 1

Cite

F. Lamadie, M. Sentis, Laurent Bruel. Digital in-line holography for near field observation of liquid-liquid flows under astigmatic conditions. LIP 2016 - The 11th International Conference on laser-light and Interactions with Particles, Apr 2016, Xi'an, China. ⟨cea-02509783⟩
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