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Large scale Monte Carlo simulation of crossflow membrane filtration for removal of particulate materials
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|Title:||Large scale Monte Carlo simulation of crossflow membrane filtration for removal of particulate materials|
|Abstract:||Membrane separation has emerged as a cost competitive, viable, and alternative way to achieve high quality effluent in comparison to conventional methods for drinking and industrial water production and also water reuse. However, membrane fouling, caused by deposition of suspended and dissolved solids, results in decreased performance of the filtration, especially a decline in permeate flux through the membrane. Membrane fouling can be minimized by chemical modification of the membrane surface, periodic backwashing/cleaning, and optimum operational conditions. Critical flux, which is defined as the flux below which no fouling occurs, is becoming a crucially important concept related to optimum operation. Several methods were used to experimentally measure the critical flux, including direct observation through membrane, mass balance, and flux-pressure observations. In this study, a large-scale Monte Carlo simulation method for crossflow membrane filtration to remove particulate materials is developed to investigate dynamic particle structures associated with the critical flux. This computational study is performed on a parallel computer platform via message passing interface (MPI). Dominant mechanisms of particle transport, including Brownian and shear-induced diffusion, are incorporated and unified into an effective hydrodynamic force acting on hard spheres in the concentrated shear flow. Biased probability distribution, including tangential and normal biases, is used in the Monte Carlo simulations. Critical fluxes are first visually estimated by observing particle configurations, and they are in a good agreement with experimental observations done by multiple researchers with various operational conditions. Effects of shear rate and particle size on the critical flux are also investigated using this force-biased Monte Carlo simulation method, which shows that repulsive particles lead to higher critical flux compared to that of hard sphere particles. Variance of the particle distribution is proposed to be an order parameter, and its second order derivative is used to estimate the critical flux. The simulated critical fluxes are in good agreement with those of experimental results using the particle mass balance method.|
|Description:||Thesis (M.S.)--University of Hawaii at Manoa, 2008.|
Includes bibliographical references (leaves 82-91).
vii, 91 leaves, bound 29 cm
|Rights:||All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.|
|Appears in Collections:||M.S. - Civil Engineering|
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