In this study, simultaneous measurements of velocity and concentration fields using the time-resolved particle image velocimetry (PIV) and planar laser induced fluorescence (PLIF) methods have conducted to investigate mixing characteristics in turbulent water flows driven by air bubbles in a cylindrical water tank. The flow rates of compressed air is changed from 1 to 5 L/min at 0.5 MPa and the corresponding range of bubble based Reynolds number is from 8,320 to 22,100. PLIF measurement results demonstrate that the mixing efficiency is enhanced with increase of gas flow rate. The sloshing motion of the free surface is also effective to the scalar mixing process since the vertical motion can be correlated with concentration fluctuation and increase turbulent dispersion process.

Volume Subject Area:
Symposium on Non-Invasive Measurements in Single and Multiphase Flows
Topics:
Bubbles, Flow (Dynamics), Turbulence, Water, Compressed air, Fluorescence, Gas flow, Lasers, Particulate matter, Reynolds number, Scalars, Sloshing, Turbulent diffusion
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 by KSME
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