8TH INTERNATIONAL SYMPOSIUM ON FLOW VISUALISATION (1998) SHORT-TIME HOLOGRAPHY APPLIED TO THE THREE DIMENSIONAL TWO-PHASE FLOW IN AN AERATED, STIRRED VESSEL

The present paper deals with the applica-tion of the short-time holography to the analy-sis of the three-dimensional two-phase flow in a aerated, stirred vessels. Both, the macroscopic structure of the flow, such as the flow field of the generated bubbles, and its microscopic struc-ture, such as the number, the size, the loca-tion, and the velocities of the generated bubbles were investigated. Two holograms of the vol-ume of interest, the entire agitator-vessel, were taken simultaneously from two viewing direc-tions which were perpendicular to one another. The developed holograms are reconstructed, and stationary images, the real images of the recorded scene, are formed three-dimensionally in front of the holographic plates. These two 3D reconstructions of the flow field, seen from different viewing-directions, were scanned by means of CCD-cameras. Computer based algo-rithms were developed in order to determine the quantities to be measured that are stored in the obtained video-images. By means of a stereo-matching module both views were correlated and the position and the three-dimensional ve-locity vector of each bubble were determined. The applicability of the used holographic tech-nique and that of the filtering and correlating modules is proven by the presented results