Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 46 for “"species transport"”.
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A 3-dimensional h-adaptive algorithm for species transport prediction
… equations for fluid flow and scalar transport; This h-adaptive algorithm, in combination with the finite element solver, has been designed to solve simple to moderately complex 3-dimensional problems on high-end PC's with at least 16 megabytes of ram, and more complex geometries on …
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Finite element analysis of nitrogen species transport and transformation in the unsaturated zone
… was developed to predict water flow and nitrogen species transport and transformation in variably saturated soil. In the finite element analysis various numerical algorithms were examined to evaluate methods of improving the efficiency of the traditional finite element approach. Results indicate …
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Modeling biotic and abiotic decay of trichloroethylene (TCE) using the Reactive Multi-Species Transport in 3-Dimensional Groundwater Aquifers (RT3D) code
… can spend long time periods in LPZs as the mass transport is mainly by diffusion. The biotic process uses an organic solute such as lactate as an electron donor and the halogenated compounds as electron acceptors to biologically transform TCE into dichloroethylene (DCE), vinyl chloride (VC), and …
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3D printing-based microfluidics for geosciences
… pore-scale processes such as CO2 dissolution and species transport in multiscale porous media. However, there are concerns regarding dimensional fidelity, shape conformity and surface quality of the 3D printed products, and therefore, the printing quality and printer limitations must be …
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Coupled radiation transport and mobile depletion for health physics and environmental impact applications
… work developed a discrete ordinates radiation transport solver and a radionuclide trace species transport solver in the MOOSE framework for Caribou. This radiation transport solver is compared to several benchmark problems to determine its accuracy with and without ray effect mitigation …
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Parallel Processing of Reactive Transport Models Using OpenMP
Transport codes are beginning to be parallelized in order to allow more complex add-ons, such as geochemical packages, to utilize finer, more accurate grids, and to reduce solution times making stochastic and Monte Carlo simulations more feasible. Most codes parallelized via MPI (message passing …
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Development of a Simulation Model for Fluidized Bed Mild Gasifier
… The Navier-Stokes equations and seven species transport equations are solved with three heterogeneous (gas-solid), two homogeneous (gas-gas) global gasification reactions. Development of the model starts from simulating single-phase turbulent flow and heat transfer to understand the …
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Simulation of Combustion and Thermal Flow inside an Industrial Boiler
… FLUENT. The 3-D Navier-Stokes equations and five species transport equations are solved with the eddy-breakup combustion model. Calculation of NOx is performed after obtaining a converged flow, thermal and combustion solution. The results provide insight into the detailed thermal-flow and …
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A 3-dimensional H-adaptive algorithm for groundwater flow and contaminant transport
The simulation of contaminant transport through the subsurface is a very useful way to effectively design mitigation methods for cleanup and prevention of the deterioration of groundwater; The GWADAPT3 code is developed using the finite-element method and mesh adaptation to simulate groundwater …
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Computational fluid dynamics modelling of PEM fuel cells to investigate transport limitations.
… models have been developed to investigate the transport limitations of fresh reactants and its effect on cell performance. The governing equations (continuity, momentum and species transport) with appropriate source terms were solved using computational fluid dynamics (CFD) technique. A user …
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A finite element segregated method for thermo-chemical equilibrium and nonequilibrium hypersonic flows using adapted grids
… problems is chemically reacting and molecular species are vibrationally excited, numerical analyses based on an ideal gas assumption result in inaccurate if not erroneous solutions. Instead, hypersonic flows must be computed by solving the gasdynamic equations in conjunction with species …
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Numerical investigation of ion transport mechanisms in electrochemical energy storage devices: Similarity correlation and exergy destruction analysis
… to handle intermittency. In this thesis, the ion transport mechanisms are studied by modeling redox flow batteries (RFBs) and intercalation-based Li-ion batteries. Redox flow batteries are an emerging technology which allows independent scaling of energy and power density making them suitable …
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Simulation of Coal Gasification Process Inside a Two-Stage Gasifier
… The 3-D Navier-Stokes equations and seven species transport equations are solved with eddy-breakup combustion model. Simulations are conducted to investigate the effects of coal mixture (slurry or dry), oxidant (oxygen-blown or air-blown), wall cooling, coal distribution between the two …
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A Three-dimensional Bay/estuary Model To Simulate Water Quality Transport
… a reaction network. Through the decomposition of species governing equations via Gauss-Jordan column reduction of the reaction network, (1) redundant fast reactions and irrelevant kinetic reactions are removed from the system, which alleviates the problem of unnecessary and erroneous formulation …
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Simplified Combustion Modeling of Composite Propellants
… rate) determined by coupled gas-solid energy/species transport analysis. Comparisons of the model with experimental observations focus on surface geometry, flame structure and the burning rate for variations in pressure, particle size, binder width and propellant formulation. Experimentally …
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Super-conformal coating and filling of high aspect ratio recessed structures by two-molecule CVD
… along the centerline of the feature because the transport of precursor molecules to the bottom becomes rate limiting. These defects undermine device properties and methods are needed to afford complete filling. One approach is to taper the two sidewalls slightly inwards. However, the requirement …
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Oscillatory Flow As A Means Of Enhanced Species Separation: A Three Dimensional Time-accurate Cfd Analysis
A fluid that contains species in the presence of a concentration gradient generates unusual phenomena when it is forced into pulsatile motion. For example, each species in the fluid has an enhanced mass transport due to pure molecular diffusion. This enhancement takes place even if there is no net …
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Conversion of Saline Water to Fresh Water Using Air Gap Membrane Distillation (AGMD)
… A one dimensional analysis for the overall transport in an AGMD process has been done in the present study considering all the mass transfer resistances present in the process. A two dimensional analysis of the heat and mass transfer process inside the feed chamber has been considered. …
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Computational fluid dynamics modelling of dissolved oxygen in oxidation ditches.
… (BOD) distribution on the DO distribution. Species transport modelling predicts the BOD and DO distribution in the ditch. De-oxygenation of local dissolved oxygen by BOD is modelled by an oxygen sink that depends on the local BOD concentration. This is a novel approach to flow modelling for …
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