SIZES AND SIZE DISTRIBUTIONS OF BUBBLES IN A BUBBLE COLUMN - COMPARISON BETWEEN THE 2 POINT ELECTRIC PROBE METHOD AND THE PHOTOGRAPHIC METHOD

In the bubble flow region of a two-dimensional bubble column, bubble sizes were measured by the two-point electric probe method and by the photographic method, and both the results are analysed and discussed. Most bubbles in the bubble column are not spherical, but can be approximated by oblate ellipsoids. But the experimental results show that the volume-surface mean diameter equivalent to spherical bubbles, which is calculated by the analysis of Ueyama et al. for spherical bubbles with data obtained by the electric probe method, agrees fairly well with that obtained by the photographic method. The major axis of a rising bubble is not always horizontal, and the analysis shows that this fact may be the principal reason for the agreement. A very simple method is presented to obtain the bubble size distribution curve from data of the electric probe method. © 1979, The Society of Chemical Engineers, Japan. All rights reserved.