Bubble motion and mass transfer in non‐Newtonian fluids: Part I. Single bubble in power law and Bingham fluids

Abstract

The Sherwood number and drag coefficient for a single gas bubble moving in a power law fluid and a Bingham plastic fluid are obtained using perturbation methods. The perturbation parameters for power law and Bingham plastic fluids are m (= n – 1/2) and E (= τ oR/U μ o), respectively. It is found that in the case of power law fluid, mass transfer and drag increase with increasing pseudoplasticity. These theoretical results are found to be in good agreement with the available experimental data and the data obtained in the present study. In the case of Bingham plastic fluid, mass transfer and drag are found to increase with increase in the Bingham number NB (= 2ε). Contours of plug flow regions, where local stresses are less than the yield stress, are obtained as a function of the Bingham number NB. These results qualitatively predict the zero terminal velocity observed for bubble motion in liquids with very high yield stress. They are also in good agreement with the trends of the results obtained previously for solid sphere motion in Bingham plastic fluids.

Oxygen transfer in liquids

“…A more expressive influence of air velocity on the value of volumetric oxygen transfer coefficient appears when the inner tube is filled with the static mixer elements, as indicated by the values of regression coefficients, a,, given in transfer from the swarm of bubbles into pseudoplastic liquids is larger when the gas holdup is lower in the system studied. 6 In the system with motionless mixer the gas power output increases with increasing air velocity and is in all cases larger than in a system without motionless mixer. In Figure 7 is shown the limited values of the gas power output for the system air-water with motionless mixer and for the system air-Neupexm solution …”

Utilization of Anabaena sp. in CO2 removal processes

“…6). The bubble rise velocity was estimated to be 0.24 m/s, while the bubble diameter was estimated as a function of fluid properties and fluid-dynamic conditions by using the equation proposed for viscous media (Bhavaraju et al 1978) (Eq. 7).…”

Bubble rise dynamics in a viscoplastic material

“…From a theoretical point of view, Bhavaraju et al [24] performed a perturbation analysis in the limit of small yield stress for a spherical air bubble.…”