Date of Award


Document Type


Degree Name

Master of Science (MS)




This study was designed to improve understanding of the motion of air bubbles in water, in order to make possible more precise mass transfer calculations.

An accurate, low cost photographic technique was developed for studying the trajectory of air bubbles rising unrestrained in water.

The effect of several variables on velocity and direction of bubble movement was studied. These include: equivalent bubble radius; temperature; contamination; release pressure; vessel size, shape and construction material, and orientation and size of the capillary tube from which the bubbles were released.

Air bubble velocities in this work were generally low, as compared to the results of other experiments for air bubbles in distilled or filtered water. For small air bubbles a smooth curve showing increase of velocity with increase in equivalent radius was obtained. When the size of the air bubbles reached the transition region where spherical shape was lost and the path deviated from rectilinearity the velocities increased with bubble radius but considerable scatter was in evidence.

It was shown that the amplitude of the bubble oscillation from the rectilinear path increased as the vertical velocity increased. The level of contamination was found to be considerably less than the amount, as stated in the literature, required to cause a reduction in bubble velocity of the magnitude found in this study.