Velocity of a Large Bubble Rising in an Inclined Rectangular Channel

Velocity of a large single bubble rising in a stationary liquid in an inclined rectangular channel was measured using silicone oil having a kinematic viscosity of 1000mm²/s. The size of cross section of the test channel was 5mm × (5–40)mm, i.e., the aspect ratio was from 1 to 8. Experiments were carried out changing the aspect ratio of cross section of the channel, the inclination angle and “posture angle”, where the “posture angle” is an angel by which the channel is rotated around the channel axis. Movement of a large bubble in an inclined circular tube is determined by the inclination angle. On the other hand, it is shown that movement of a large bubble in an inclined channel is influenced also by the posture angle beside the inclination angel, i.e., the posture angle is an important parameter in an inclined rectangular channel. Relations among the rising velocity, the inclination angle, the posture angle and the aspect ratio were obtained by the experiments.