Rise of Taylor bubbles through narrow rectangular channels

Experiments have been performed to investigate the rise of Taylor bubbles in narrow rectangular channels (0.0051 m × 0.0027 m × 0.8 m and 0.01 m × 0.0027 m × 0.8 m). The studies conducted for both stationary and moving liquid have revealed definite influence of channel orientation, dimension and inclination on the propagation velocity of Taylor bubbles. The rise velocity first increases and then decreases as the channel is moved from the horizontal to the vertical position with its broad face always lying in a vertical plane. This is in agreement to the results reported in literature for circular as well as non-circular geometries. On the other hand, the rise velocity increases continuously with inclination when the channel is oriented with its broad face in a horizontal plane. The explanation for this difference in behavior has been obtained through visualization and photographic recording. It has also been noted that the bubble rise velocity in the vertical orientation could not be predicted by any of the existing correlations proposed for non-circular channels.