In the fields of mechanical and chemical engineerings, it is important to measure diameters of bubbles in liquid accurately. Many measuring methods of bubble diameter have been reported. Almost all of them use photograph and are unsuitable for a real-time measurement of bubble diameter.
In this paper, a new dynamic measuring method of bubble diameter using CCD image sensor is described. Experimental results demonstrate that bubble diameters measured by a system using the method are good agreement with those measured by photographs within the linearity of ±1.0%.
A drive of CCD image sensor at scanning time of 0.25ms enable the system to measure bubble diameter changing fast in 15ms.