Mechanics of bubble motion and deformation in non-newtonian media

Bubble Rise Phenomena in Non-Newtonian Crystal Suspensions

“…The bubble shapes in terms of bubble eccentricity (which is defined as the ratio of maximum bubble width to the maximum bubble height) are also dependent on rheological properties of the liquids. The literature suggests that prolate shaped ( E < 1) and oblate shaped bubbles ( E > 1) are usually observed in non-Newtonian viscoelastic liquids (Acharya, 1977). The bubble shapes observed in this study are mainly oblate shaped as the eccentricity was found to be greater than 1.…”

“…The quantitative description of the bubble shapes in terms of the process and rheological parameters can be seen in terms of an eccentricity (E) or aspect ratio defined as the ratio of the maximum width to the maximum height. Literature suggests that prolate shaped (E < 1) and oblate shaped (E > 1) bubbles should be treated separately (Acharya et al, 1977). A quantitative relationship between the bubble eccentricity and the relevant dimensionless groups has been attempted by Miyahara and Yamanaka (1993).…”

“…Again, a new dimensionless group 1 G which is a measure of the ratio of the elastic stresses to surface tension stresses can be simplified (Acharya et al, 1977) as:…”

“…In this region, We can be defined as the ratio of the internal stresses to the surface tension stresses; this controls the bubble deformation. In this context for high Reynolds number flow, another new dimensionless group G2 has been simplified (Acharya et al, 1977).…”

Bubble rise velocities and drag coefficients in non-Newtonian polysaccharide solutions

“…Among the most interesting phenomena observed in the dynamics of bubble rise in non-Newtonian liquids is the bubble volume-terminal velocity curve discontinuity (Chhabra, 1988). It was observed by several authors, including Astarita and Apuzzo (1965), Acharya et al (1977), Calderbank et al (1970), and Rodrigue et al (1996). The above-mentioned discontinuity is represented by a jump in the bubble terminal velocity when the bubble volume was increased over a certain limiting value.…”