Air bubble trajectories in polymeric solution and crystal suspension

The experimental results of bubble trajectory in xanthan gum solution, xanthan gum crystal suspension and water are presented in this paper. The suspension was made of 0.05% concentration of xanthan gum solution with 1% (by weight) of 0.23 mm polystyrene crystal particle. The characteristic of the air bubble trajectory in these three different liquids is analysed. The influences of the Reynolds number andthe Weber number on bubble trajectory are discussed. The results show that the smaller bubbles (0.1 mL) experienced more horizontal movement in water than in other liquids. On the other hand, larger bubbles (>5mL) produced less spiral motion in water than in other liquids. Conversely, the smaller bubbles (0.1 mL)followed least horizontal motion and larger bubbles (>5mL) produced more spiral motion for crystal suspension. Path instability occurred at the bubbles of 2mL and 5mL and they induced both zigzag and spiral trajectory for all liquids. At low Re and We, smaller bubble produced a zigzag trajectory while larger bubbles (> 5mL) showed a spiral trajectory at high Re and We.