Development of High-Speed Photography and Image Processing Method for the Characterization of Bubbles in a Bubble Column

In the present research, a square bubble column has experimentally been utilized in order to quantify the important hydrodynamic properties of bubbly liquid/gas two phase flows, such as bubble velocity and diameter, flow pattern as well as oscillation frequency of the gas phase via the high-speed video recorder. Results were then processed using new techniques of image processing. The column was fabricated from plexy-glass which was dimensionally 205120cm (cross sectionheight). Results indicated that gas superficial velocity varied from 0.1 to 0.7 cm/s. Three cameras with different speeds were employed (20, 500 and 600 frames per second) to evaluate the bubble characteristics and MATLAB 7.4 (2007a) was used for image analysis. Oscillation frequency of gas phase was obtained using a new method with accuracy close to 95%. At coalescence condition, Mean Sauter Diameter (MSD) of bubbles was calculated with accuracy of about 99.8%. For the first time, bubble velocity was computed by "minimum distance with upper limit" method in the bubble column.