LDA Characterization of the Velocity Field around a Growing and Rising Bubble in Shear-thinning Fluid

W. Fan and X. Yin

Abstract
Laser Doppler anemometry (LDA) has been employed to quantify the liquid velocity field around a single bubble in its generating and accelerating stage in carboxymethylcellulose (CMC) aqueous solution. The instantanoues velocities were treated by Reynolds time-averaged method, and mean velocities and its contours in both axial and radial directions were investigated. The results show that in vertical direction, the flow field characteristics of the liquids around the bubble are determined by bubble formation-rise mechanism, whereas in horizontal direction they are governed by the relative position with the bubble shear radius. The contours of axial and radial mean velocity in the test section take on the shapes of inverted trapezoid and butterfly forewing, respectively.

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords
bubble formation, velocity field, shear-thinning, laser Doppler anemometry