Momentum And Heat/Mass Transfer Phenomena Of Contaminated Bubbles In Power-Law Liquids
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2014
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Abstract
The presence of impurities or contaminants or surface active materials is unavoidable in many industrial applications in which bubbles play important role. The momentum and heat/mass transfer from bubbles can also be affected by wall confinement, neighboring bubbles and rheology of surrounding continuous liquid. Thus, in this dissertation, the momentum and heat/mass transfer phenomena of unconfined and confined single contaminated bubbles and those of swarms of contaminated bubbles in Newtonian and power-law liquids are numerically elucidated. The non-diffusing surfactant effects are incorporated using the spherical stagnant cap model whereas the effect of volume fraction of contaminated bubble swarms is studied by the use of free surface cell model. The flow behavior and heat/mass transfer phenomena of unconfined single contaminated bubbles in power-law fluids are studied using both in-house solver and Ansys Fluent. The momentum and heat/mass transfer phenomena of confined contaminated bubbles in power-law fluids are studied using Ansys Fluent. The momentum and mass transfer phenomena of swarms of contaminated bubbles is studied using in-house solver. In the in-house solver, a finite difference method based simplified marker and cell (SMAC) semi implicit algorithm used with convective terms being discretized using the quadratic interpolation for convective kinematics (QUICK) scheme; while the diffusive terms discretized using central differencing scheme. In Ansys Fluent, the conservation equation of mass and momentum are solved using the semi-implicit method for pressure-linked equations (SIMPLE) algorithm along with QUICK scheme for convective terms. Furthermore, the contamination effects on the drag coefficients, streamline patterns, surface pressure, surface vorticity, surface viscosity, isotherm contours, surface Nusselt number and average Nusselt number of confined and unconfined single contaminated bubbles and of swarms of contaminated bubbles in power-law fluids are...
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Supervisor: Nanda Kishore
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CHEMICAL ENGINEERING