High-speed video microscopy and computer enhanced imagery in the pursuit of bubble dynamics

The equipment and method for studying transient bubble dynamics are describ ed in simple sonochemical reactors and presented using still frames from hi gh-speed video microscopy (500 fps). Effects on aeration bubbles (mean size 1-3 mm diameter) and the cavitation induced species (<0.5 mm diameter) are studied. The images are computer enhanced to improve interpretation of suc h features as the maximum ellipsoidal distortion at the nodal sound plane a nd spherical shape regain with due consideration of energy involved and exp ansion effects at the nodal sound plane. Also immersion depth/pressure effe cts, as the bubbles transcend the sound field column, in the cylindrical re actor, are recorded for evaluation of nodal and antinodal sound wave effect s. Positions of the nodal and antinodal regions are marked using a novel tu ngsten halogen bulb technique and verified using the sonoelectroluminescent approach with the classical luminol/hydrogen peroxide chemistry which is e nhanced under the sound field conditions. (C) 2000 Elsevier Science B.V. Al l rights reserved.