Bubble size and velocity measurement in gas—liquid systems: Application of fiber optic technique to pilot plant scale

A new fiber optic probe was developed for the detection and measurement of bubble sizes and velocities in a gas‐liquid column. The probe is made of a single 1 mm plastic fiber with a sharp wedge tip. The calibration was carried out on a laboratory scale unit using a cine‐photographic technique to verify the measurements. Bubble velocities were calculated using two identical parallel fibers and the cross‐correlation technique. With the velocities and the passage time determined, it was then possible to determine the bubble diameter. Bubble diameters were within 10% of the measurements obtained with the cine‐photographic technique. After calibration, measurements were carried out on a pilot scale unit.