Simultaneous Measurement of 3-Dimensional Shape and Behavior of Single Bubble in Liquid Using Laser Sensors

Abstract

A novel sensing system of bubble shape, surface area, volume and rising velocity using three coupled laser sensors was developed. To confirm the reliability of the system, the bubble shape was simultaneously measured using both a high-speed video camera and this system for an identical rising single bubble. The bubble’s outline analyzed using the laser scanning system corresponded well with that analyzed by the video image analysis. The measured rising velocities of bubbles agreed well over a wide range of liquid viscosity with the data of Grace (1973), and Bhaga and Weber (1981). Moreover, the measured surface area of a bubble agreed well enough with the estimation of Tadaki and Maeda (1961) under their experimental condition.
With this system, not only rising velocity of a single bubble but also its three-dimensional shape and surface area could be more precisely and quickly measured in real-time.