Investigation of air bubble motion in counter-current water flow conditions

Bezdegümeli, Uğur
In this thesis study, air bubble motion in counter-current water flow conditions in a vertical pipe is investigated experimentally. For this purpose, a test set-up was designed and constructed. Images of motions of single bubbles, having different diameters in the range of 3.0-4.8 mm, generated by specially designed bubble injectors were recorded by using a monochrome camera, an image capture card and a PC. Recorded video images were processed to obtain the necessary data for the The purpose of the study is to determine variation as a function of the equivalent bubble diameter, water flow velocity and related dimensionless numbers; Reynolds, Re; Eötvös, Eo; and Weber, We, and is to investigate the bubble shapes and bubble travel paths. Bubble behaviour was investigated at six different counter-current water flow velocities (6.5 cm/s, 7.9 cm/s, 10.5 cm/s, 12.9 cm/s, 15.4 cm/s, and 18.2 cm/s) in addition to stagnant water condition which is taken as the reference case. The direction of the bubble motion is upwards and the direction of the water flow is downwards (i.e. counter-current). Distilled water was used in the experiments. The results of this thesis study for the stagnant water condition have shown good consistency with the previous theoretical and experimental studies found in the literature. For the studied range of bubble diameters, it is observed that the bubble average relative velocity for a certain bubble diameter is less under counter-current water flow conditions than that under stagnant water condition and the drag coefficient values for a certain bubble diameter is higher under counter-current water flow conditions than those under stagnant water condition.


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Citation Formats
U. Bezdegümeli, “Investigation of air bubble motion in counter-current water flow conditions,” Ph.D. - Doctoral Program, Middle East Technical University, 2003.