LASER ULTRASONICS FOR BUBBLY FLOW DETECTION

Laser ultrasonics was used to study flow of air bubbles in still water . An experimental system was developed utilizing a Nd:YAG laser to gen erate ultrasonic pulses in the MHz range and a He-Ne laser beam to det ect echoes from the bubble-water interfaces. Several methods were appl ied to compare ultrasonic waveform parameters with air flow rates. The results show a correlation between the number and magnitude of amplit udes in the waveform and the bubble production air flow rate. (C) 1998 Elsevier Science B.V.