Measurements of Bubble Characteristics: Comparison Between Double Optical Probe and Imaging

The objective of this study is to evaluate the accuracy of double optical probe technique in local two-phase flow measurements. Able to provide both bubble velocity, chord length, and gas hold-up, this technique involves nevertheless delicate signal treatment procedures and, being intrusive, depends on probe tips configurations and sizes. During probe-bubble interactions, bubble surface is occasionally deformed and this can complicate measurements analysis. The current study is focussed on the rise of single bubbles of known sizes in still water (equivalent diameter of 2.15mm and 4.5mm). Bubble parameters obtained from digital image processing method and from a double optical probe are compared statistically.