Bubble Dynamics Measurements Using Four‐Point Optical Probe

By conducting an analysis of the measurement errors it was found that bubble dynamics obtained by two‐point probes can be highly inaccurate. A four‐point optical probe with appropriate data processing algorithm has been developed so that the bubble velocity vector can be obtained. This probe provides directly the value of specific gas‐liquid interfacial area. However, for obtaining accurate values of bubble velocity and size, the four‐point probe must be calibrated by a CCD camera at the same conditions. Calibration columns have been developed for this purpose where the bubble size and velocity can be varied to calibrate the measurements by the four‐point optical probe against a CCD camera.