Vivek V. Buwa
Advanced  Flow Characterization

Dynamics of Gas-Liquid Flow and Mixing in a Shallow Vessel

Gas–liquid reactors are widely used for different applications in the chemical, metallurgical, oil and gas industries. These reactors are broadly categorized into two groups namely tall columns (with height to diameter ratio (H/D) > 5), e.g., bubble column, airlift reactor, etc., and shallow vessels (H/D < 1), e.g., Basic Oxygen Furnace (BOF), Ladle, etc. In these reactors, liquid–phase mixing is achieved either by mechanical agitation or mixing induced by gas bubbles. In the metallurgical industries, due to high temperatures and harsh environment in the molten metal baths, gas–induced mixing is used in the shallow vessels. The extent of gas–liquid mixing is closely related to the local liquid flow field induced by single/multiple bubble plumes and different bottom blowing configurations. In shallow vessels, the free gas–liquid interface influences the meandering motion of the gas plume and also the local liquid recirculation flow.

Furthermore, the top blowing intensifies the sloshing motion of the gas–liquid interface. This leads to change in the liquid flow characteristics and in turn in the overall mixing process. Therefore the primary focus of present work is to understand the effects of (i) uniform and differential flow schemes, (ii) free gas–liquid interface, (iii) combined top and bottom gas blowing configuration and bubble size on the liquid–phase velocity distribution, dynamics of gas–liquid flow and turbulent quantities (e.g., turbulent kinetic energy, rate of kinetic energy dissipation, Reynolds stresses, etc.) by Particle Image Velocimetry (PIV) and their role in liquid phase mixing by Laser Induced Fluorescence (LIF) measurements.
Schematic of experimental set–up
                            Measurement planes                                                                                      Snapshot of (i) time–averaged liquid field velocity contour,
                                                                                                                                                          (ii) streamlines and (iii) tracer distribution of the plane 1
PIV Videos:                                                         Instantaneous liquid phase velocity
LIF Videos:                                                    Time–evolution of tracer distribution (LIF)

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