Two-phase bubbly flow velocity measurements using pulsed laser velocimetry

Digital Pulsed Laser Velocimetry (DPLV) is a novel full-field, two dimensional, noninvasive, quantitative flow visualization technique. The technique described here includes the use of direct digitization of the images for two-phase bubbly flow analysis using a high resolution imaging system. The image data is stored for further analysis by a series of new image processing and analysis software developed for flow experiments. An image finding, smoothing, and defining program is also developed. This program groups pixels that could logically be defined as one image, smooths that image and calculates important parameters for the image. In the technique, images via a high resolution camera (1024 1024), ten consecutive frames of data separated by a time increment of 150 ms, are recorded. Each of these ten frames contains the images of bubbles at that one instant of time. Another program is developed to match the bubbles from each of the frames into tracks of bubbles through time. The program uses a statistical technique to determine the best possible path of the bubbles. The ability of pulsed laser velocimetry with these image processing techniques to capture simultaneous and quantitative rather than qualitative information is its most important capability.

American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED

Two-phase bubbly flow velocity measurements using pulsed laser velocimetry Conference Paper