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The present study investigates the effect of trapezoidal type columns to rise velocity of a single bubble in quiescent water using a couple level set volume of fluid (CLSVOF) methods. The bubble rising characteristics such as spatial distribution and shape deformation in different types of trapezoidal columns with inclination angles of 3°, 6°, 9° from vertical wall will be presented. The results from these cases will be compared with a benchmark case which is based on a rectangular domain (0°). The bubble rising velocity reduces with the increase of trapezoidal angle. Subsequently, the bubble rising distance for a given particular total time reduces with the increase of the trapezoidal angle, which enhances the lateral distribution of a bubble from left to right and vice versa of the column with the increase of the time, may enhance the gas hold up, the heat and mass transfer between gas and liquid. [ABSTRACT FROM AUTHOR]

The dynamical characteristic of a single bubble rising in non-Newtonian fluid was investigated experimentally. The bubble aspect ratio and rising velocity were measured by high speed camera. The shape regimes for bubbles in non-Newtonian fluids was plotted by means of Reynolds number Re, Eotvos number Eo and Morton number Mo. The effects of bubble shape and liquid rheo-logical property on the total bubble drag coefficient were studied. A new empirical drag coefficient correlation covering spherical bubble and deformed bubble was proposed, the predicted results shows good conformity to experimental values over a wide range of 0.05 < Re < 300. [ABSTRACT FROM AUTHOR]

Volume of Fluid (VOF) method was applied to investigate the hydrodynamics of single elongated bubble propagation in inclined pipes. Specially, a moving reference frame attached to the bubble nose was implemented in ANSYS FLUENT. The CFD model was validated with experimental data on the bubble rising speed in inclined pipes with stagnant liquid. The model performance with various turbulence models was studied. The effects of pipe inclination on bubble shape, propagation speed, velocity profile and wall shear stress distribution were analysed. The effect of flowing liquid on the bubble propagating hydrodynamics was also investigated. [ABSTRACT FROM AUTHOR]