Some applications of integral and spatial averaging to the mechanics of dispersed phase systems /
In this document, we apply integral and spatial averaging to
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742745651&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | In this document, we apply integral and spatial averaging to problems involving suspensions and thin films. The first problem considered is the simultaneous flow and sedimentation of a suspension in a narrow vertical channel. The suspension, formed from monodisperse spheres in a Newtonian fluid, is treated as a homogeneous fluid with an effective viscosity. The velocity field and locations of the apparent dividing surfaces between the suspension and the solids free clarified zone above and the sediment below are obtained analytically for the limiting case of slow settling velocity. In the second problem, a volume averaged approach is used to obtain the hindrance function for the sedimentation of a moderately concentrated suspension of uniform non-Brownian spheres. The spheres are assumed to be arranged in regular array. The velocity field in the vicinity of a sphere is obtained by considering pairwise interaction with its nearest neighbors. The average velocities of the fluid and solid are estimated from a cell-like approach, but unlike most previous work, no artificial boundary condition is imposed and the final result is relatively insensitive to whether the array is cubic or closely packed rhombic. Good agreement with experimental data is found. For the third problem, the effect of surface properties and mass transfer on the thinning of a plane-parallel film containing a partially soluble surfactant is studied. The effects of surface viscosities, surface tension gradient, and London-van der Waals forces are included in the analysis. The mass transfer is considered to be controlled by adsorption. Recognizing that the film is limited, we allow for the depletion of surfactant through surface flow. The analysis is applied to a sodium dodecylsufate NaCl system. The last problem considered is the hydrodynamics of film drainage with no mass transfer. This problem is normally treated using lubrication theory. Bird et al. [Dynamics of Polymeric Liquids, Vol. 1 Fluid Mechanics, (1977)] suggested an alternative approach. We compare these two approaches and find that lubrication theory neglects an edge effect. When the surfaces of the film are mobile, there is an additional normal force. Though typically negligible, in some cases this normal force may have an effect. |
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| Item Description: | Vita. "Major Subject: Chemical Engineering". |
| Physical Description: | x, 181 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |