Volumetric characterization of dispersed two-phase flows by digital image analysis

• Published in: Measurement science & technology Vol. 11; no. 8; pp. 1152 - 1161
• Main Authors: Lecuona, A, Sosa, P A, Rodríguez, P A, Zequeira, R I
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.08.2000; Institute of Physics
• Subjects: Computers in experimental physics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Image processing; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Optical elements, devices, and systems; Optical instruments, equipment and techniques; Optics; Physics; Range finders, remote sensing devices, laser doppler velocimeters, sar, and lidar; Optical measurement; Multiphase flow; Image processing; Flow measurement; Particle image velocimetry; Overlap; Digital image; Particle size measurement; Particle tracks; Experimental study; Velocity measurement
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/0957-0233/11/8/309

A digitally-based image analysis system has been developed for the experimental determination of size, spatial distribution and two components of velocity for particles suspended in any clear fluid flow. A special characteristic of the system is its suitability for relatively large particles (some mm in diameter) which are difficult to measure with other systems. The system includes a procedure for classification of the particles in the image, the separation of the partially overlapped particles and the selection of those that are found in the control volume. These parameters serve as a basis for velocity determination through a particle tracking algorithm (PTV) which is based on iteratively estimating the match probability as a measure of the likelihood of pairing. The depth of the control volume is obtained with a new technique based on the loss of focus of the particles in the image, combined with diffuse illumination provided by twin short-pulse argon spark discharge lamps. The system has been extensively checked using calibrated micro-balls and sprays that simulate rain. (Original abstract - amended)