Effect of scale on liquid recirculation in bubble columns

Gravity-Driven Bubbly Flows

“…Nevertheless, the findings stress the need for an improved description of the turbulence. Kumar et al (1994) used gamma-densitometry tomography to measure the cross-sectional, long-time averaged gas holdup distribution in the bubble columns. As was already reported by Hills, the gas fraction profile is symmetric and peaks in the center.…”

Quantitative tomographic measurements of opaque multiphase flows

“…Finally, Kumar et al (1994) addressed the biggest difficulty with the two-fluid model: the Reynolds shear stress term has not yet been accurately modeled or predicted in either laboratory or industrial flow scales, making the scaleup of laboratory results difficult. Many versions of the one-dimensional bubble-colti equations have been developed with different models for the shear stress term, z=, but no model has successfully recreated all velocity or gas volume fraction data.…”

“…The one-dimensional two-phase bubble-column model assumes steady-state, axisymmetric flow that is fully developed and involves no end effects. The largest source of uncertainty in the two-fluid model (even in its simplified one-dimensional two-phase form) is the stress tensor, which has been simplified in different ways with varying degrees of success (Kumar et al, 1994).…”

Engineering Development of Slurry Bubble Column Reactor (Sbcr) Technology

“…The parameters a, b, c, d and e were obtained by Kumar et al (1994) after extensive data on liquid recirculation velocities from CARPT were considered, as well as results from experiments of other researchers who have made measurements of the liquid recirculation velocity by other experimental means.…”

“…With the gas holdup profile as input, the liquid velocity profile can be readily computed by a procedure described elsewhere (Kumar, 1994;Kumar et al, 1994).…”