(562d) Turbulence Analysis of a Cylindrical Bubble Column

Bubble columns are widely used in industrial applications, due to their simple construction, operation and they can promote high heat and mass transfer rates.  However, their fluid dynamics is very complex, and several studies are still in progress concerning iteration forces and turbulence. 

Turbulence plays an important role on the bubble columns performance, since it contributes for bubbling break up and coalescence, as well as for estimating mass and heat transfer. In a bubble column this phenomenon is induced by the bubbles, which differs from the so-called true turbulence, like grid generated. The difference between them is the slope of the energy spectrum in inertial subrange, for the induced one is about -3, while the grid generated -5/3, this is a significant feature in a bubbly flow.

In this context, this study proposes an experimental and numerical investigation of the bubble influence on the flow turbulence. Liquid velocity profiles and turbulence fluctuations were obtained by PIV technique, bubble information with shadowgraphy. Pressure data were acquired for the spectrum analysis. Numerical simulations were performed with a CFD Commercial code. Liquid and bubble velocity profiles were compared with the simulations for validating the model. A comparison between the experimental and numerical spectrum data were also performed.