Author
Abstract
A mechanistic model is developed to account for the collision between a
single particle and a single bubble in a liquid medium. Based on the model, two
penetration criteria are established under which the particle is predicted to
penetrate through the bubble if any of the two criteria is satisfied. It is shown that
the particle penetration is only a necessary, but not sufficient, condition for bubble
disintegration in the case of single particle-single bubble collision. The penetrated
bubble is shown to deform into a doughnut shape and the subsequent bubble
breakage is made through the necking mechanism of the doughnut-shape bubble.
Bubble disintegration occurs only if the penetrating particle has a diameter greater
than the height of the doughnut-shape bubble. The column is constructed of
Plexiglas with an internal diameter 10 cm and a height of 180 cm. Experiments
are also performed for single particle-single bubble collision in water, using three
different particles (2 mm, 3 mm glass beads and 3*3 mm PVC cylinder) with
Reynolds no. and Weber no. are (953, 1512 and 840) and (5.68, 9.45 and 5)
respectively . Two markedly different collision phenomena are observed. A small
and/or light particle is unable to penetrate through the bubble and is ejected after
collision. A medium particle can penetrate through the bubble but may not break
the bubble. The two phenomena are all well predicted by the proposed model.
Keywords
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