The Optical Principles of PFBI Approach

摘要

The present paper describes a technique based on planar fluorescence for round bubble imaging in turbulent two-phase flows. Theoretical principles of the approach are described in terms of geometrical optics, and the result of the method application to a test case on singly rising bubbles is presented. One of principal advantages of the technique, named Planar Fluorescence for Bubbles Imaging (PFBI), is that bubbles located far away from the measurement plane become defocused rapidly, which allows to retrieve experimental information in a certain rectangular measurement volume of a low thickness. Due to the high degree of locality, PFBI represents a rather convenient tool for identification of round bubbles located within and very close to the laser sheet exploited for PIV measurements in a liquid phase.