Coanda Effect on Liquid Flow Characteristics in a Bubbling Jet Rising near the Side Wall of a Cylindrical Vessel
An air-water bubbling jet rising near the side wall of a cylindrical vessel is known to be pulled towards the side wall through the Coanda effect. Once the bubbling jet attaches to the side wall, it rises along the side wall all the way. The mean velocity and turbulence components of water flow in the bubbling jet were measured with a two-channel laser Doppler velocimeter. In the vertical (axial) region located above the attachment position, the horizontal (radial) distributions of the axial mean velocity component <I>u</I> and the root-mean-square values of the axial and radial turbulence components, <I>u</I>'<sub>rms</sub> and <I>v</I>'<sub>rms</sub>, followed their respective similar distributions just like the horizontal distributions of bubble frequency and gas holdup. The maximum values of <I>u</I> and <I>u</I>'<sub>rms</sub> agreed favourably with those obtained in a vertical bubbling jet free from the Coanda effect, and hence, these values were not affected by the side wall. However, the maximum value of <I>v</I>'<sub>rms</sub> became smaller than that in the vertical bubbling jet because the horizontal turbulence motions were suppressed due to the confinement effect of the side wall.
- ISIJ international
ISIJ international 39(3), 213-218, 1999-03-15
The Iron and Steel Institute of Japan