On the Shape and Velocity of Single Air Bubbles Rising in Various Liquids

Abstract

The shape and the velocity of bubbles in various liquids listed in Table 1 were measured on photographs The shape bubble size taken of through gas bubbles a stroboscope. changed increased. The experimental from the bubble was almost spherical and traveled spherical results to ellipsoidal, showed that up and then to to the Reynolds in a rectilinear path. In the range mushroomlike, number as the of 2M-0.23, of 2 <16.5, ellipsoidal bubbles of ReM0.23>16.5, were formed the bubble and as the bubble was of mushroom size shape. increased These the shape changes in became shape flatter. are plotted In the range in terms of d/a and ReM0.23 in Fig. 12, from which experimental equations, Eqs. (12)•`(15) are derived. These are applicable to bubbles in all solutions except for surface active agent solution. The bubbles in surface active agent solution remained spherical in much bigger size than those in pure water. Data bubbles, on the terminal velocity the surface tension and of gas bubbles the viscosity are shown were found in Fig. 6. to be important Of spherical and factors determining ellipsoidal the rate of rise. Mushroomlike bubbles rose independently of liquid properties. To correlate the results, dimen sionless obtained parameters, CD, for all solutions Re and M were except for surface well with the data of previous investigators employed active and experimental agent solution. equations, These equations Eqs. (9)•`(11), were agree approximately summarized in Fig. 16. The presence of certain surface active with substances in water the drag of bubbles served in pure to