To seek and describe the influence of bubble size on geometric and motion characteristics of the bubble,six nozzles with different outlet diameters were selected to inject air into water and to produce different bubbl...To seek and describe the influence of bubble size on geometric and motion characteristics of the bubble,six nozzles with different outlet diameters were selected to inject air into water and to produce different bubble sizes.High-speed photography in conjunction with an in-house bubble image processing code was used.During the evolution of the bubble,bubble shape,traveling trajectory and the variation of bubble velocity were obtained.Bubble sizes acquired varied from0.25to8.69mm.The results show that after the bubble is separated from the nozzle,bubble shape sequentially experiences ellipsoidal shape,hat shape,mushroom shape and eventually the stable ellipsoidal shape.As the bubble size increases,the oscillation of the bubble surface is intensified.At the stabilization stage of bubble motion,bubble trajectories conform approximately to the sinusoidal function.Meanwhile,with the increase in bubble size,the bubble trajectory tends to be straightened and the influence of the horizontal bubble velocity component on the bubble trajectory attenuates.The present results explain the phenomena related to relatively large bubble size,which extends the existing relationship between the bubble terminal velocity and the equivalent bubble diameter.展开更多
One characteristic of electro-flotation is the presence of micro bubbles that are well known for improving the flotation performance of fine particles. An electro-flotation method was studied with fine scheelite and f...One characteristic of electro-flotation is the presence of micro bubbles that are well known for improving the flotation performance of fine particles. An electro-flotation method was studied with fine scheelite and fluorite particles sized into three different fractions. Experiments were performed in a modified Hallimond tube. We investigated the effects of gas holdup, particle size, and different mesh electrode apertures on mineral recovery. Flotation results show that two size fractions show increased flotation recovery as the gas holdup increases. For the sized scheelite and fluorite, the flotation effect is diverse for different sizes of the cathode aperture. Pictures of the bubbles taken by a high speed CCD were used to determine the hydrogen bubble size distribution generated as a function of collector, current density, and electrode size. The diameters of the hydrogen bubbles ranged from 12 to 117μm in alkaline conditions.展开更多
基金Project(51676087)supported by the National Natural Science Foundation of China
文摘To seek and describe the influence of bubble size on geometric and motion characteristics of the bubble,six nozzles with different outlet diameters were selected to inject air into water and to produce different bubble sizes.High-speed photography in conjunction with an in-house bubble image processing code was used.During the evolution of the bubble,bubble shape,traveling trajectory and the variation of bubble velocity were obtained.Bubble sizes acquired varied from0.25to8.69mm.The results show that after the bubble is separated from the nozzle,bubble shape sequentially experiences ellipsoidal shape,hat shape,mushroom shape and eventually the stable ellipsoidal shape.As the bubble size increases,the oscillation of the bubble surface is intensified.At the stabilization stage of bubble motion,bubble trajectories conform approximately to the sinusoidal function.Meanwhile,with the increase in bubble size,the bubble trajectory tends to be straightened and the influence of the horizontal bubble velocity component on the bubble trajectory attenuates.The present results explain the phenomena related to relatively large bubble size,which extends the existing relationship between the bubble terminal velocity and the equivalent bubble diameter.
基金National Natural Science Foundation of China (No. 51074184)
文摘One characteristic of electro-flotation is the presence of micro bubbles that are well known for improving the flotation performance of fine particles. An electro-flotation method was studied with fine scheelite and fluorite particles sized into three different fractions. Experiments were performed in a modified Hallimond tube. We investigated the effects of gas holdup, particle size, and different mesh electrode apertures on mineral recovery. Flotation results show that two size fractions show increased flotation recovery as the gas holdup increases. For the sized scheelite and fluorite, the flotation effect is diverse for different sizes of the cathode aperture. Pictures of the bubbles taken by a high speed CCD were used to determine the hydrogen bubble size distribution generated as a function of collector, current density, and electrode size. The diameters of the hydrogen bubbles ranged from 12 to 117μm in alkaline conditions.
