Mechanical Engineering Commons^™

Quantification Of Flows Emerging From Small Pores In Plane Walls, Matia Peter Edwards

Electronic Thesis and Dissertation Repository

Current membrane separation processes are limited in high production and high purity settings due to a trade-off between selectivity and permeance. Methods of creating nanoscale geometries in 2D materials are emerging and present an opportunity for fast, size selective mass transport that can be tailored to a wide array of applications. This thesis develops a method for quantifying flow through small pores in plane walls based on the behaviour of a solute dispersed in a downstream reservoir. This method is validated for a range of micropore diameters, for which flow rates can be calculated with confidence, and is shown to …

Non-Circular Hydraulic Jumps Due To Inclined Jets, Ahmed Mohamed Abdelaziz

Electronic Thesis and Dissertation Repository

When a laminar inclined circular jet impinges on a horizontal surface, it forms a non-circular hydraulic jump governed by a non-axisymmetric flow. In this thesis, we use the boundary-layer and thin-film approaches in the three dimensions to theoretically analyse such flow and the hydraulic jumps produced in such cases. We particularly explore the interplay among inertia, gravity, and the effective inclination angle on the non-axisymmetric flow.

The boundary-layer height is found to show an azimuthal dependence at strong gravity level only; however, the thin film thickness as well as the hydraulic jump profile showed a strong non-axisymmetric behaviour at all …

3d Printing Technology Applied In Lithium Metal Batteries: From Liquid To Solid., Xuejie Gao

Electronic Thesis and Dissertation Repository

Li-metal batteries are strongly considered to be one of the most promising candidates for high energy density energy storage devices in our modern society. However, the state-of-the-art Limetal batteries are still limited by several challenges including 1) low energy/power density; 2) Li dendrite growth; 3) low coulombic efficiency, and 4) safety concerns within the liquid electrolyte. This thesis mainly focuses on addressing these challenges by using a 3D printing technique to realize high energy/power density Li-metal batteries.

A self-standing high areal energy density cathode for Li-S battery was developed by the 3D printing method in the first part. The optimized …

Understanding The Interplay Between Fluid Mechanics And Particle Size Distributions For Filtration Of Flocculated Mixtures, Brooke Remler

Electronic Thesis and Dissertation Repository

The breakdown of nutrients in biological processes in wastewater treatment require a sub- stantial amount of energy, contributing to greater greenhouse gas (GHG) emissions. Floc- culation can be used to reduce the loading on a biological process by increasing removals during primary treatment in devices such as a rotating belt filter (RBF). The relationship between shear conditions, defined by velocity gradients (G-values) and floc size is crucial. Understanding G-value magnitudes and distributions within an RBF, corresponding trans- port network, and the effects on floc size degradation are needed to maximize removals. G-values were calculated using a newly developed approach, improving …

A Model For Complex Heat And Mass Transport Involving Porous Media With Related Applications, Furqan A. Khan

Electronic Thesis and Dissertation Repository

Heat and mass transfer involving porous media is prevalent in, for example, air-conditioning, drying, food storage, and chemical processing. Such applications require non-equilibrium heat and mass (or moisture) transfer modeling inside porous media in conjugate fluid/porous/solid framework. Moreover, modeling of turbulence and turbulent heat and mass transfer becomes essential for many applications. A comprehensive literature review shows a scarcity of models having such capabilities. In this respect, the objectives of the present thesis are to: i) develop a formulation that simulates non-equilibrium heat and mass transfer in conjugate fluid/porous/solid framework, ii) demonstrate the capabilities of the developed formulation by simulating …

Numerical Modeling Of Solidification Process And Prediction Of Mechanical Properties In Magnesium Alloys, Mehdi Farrokhnejad

Electronic Thesis and Dissertation Repository

A formulation used to simulate the solidification process of magnesium alloys is developed based upon the volume averaged finite volume method on unstructured collocated grids. To derive equations, a non-zero volume fraction gradient has been considered and resulting additional terms are well reasoned. For discretization the most modern approximations for gradient and hessians are used and novelties outlined. Structure-properties correlations are incorporated into the in-house code and the proposed formulation is tested for a wedge-shaped magnesium alloy casting. While the results of this study show a good agreement with the experimental data, it was concluded that a better understanding of …

Improved Non-Linear Solution Of Dip Coating Flow, Omar Bin Yusuf

Electronic Thesis and Dissertation Repository

A thin layer of film is developed on the surface of a substrate in the dip coating process where the substrate is initially immersed into the coating fluid and then withdrawn continuously from the coating fluid bath. In this study a two dimensional flow of the thin film for a Newtonian fluid is examined theoretically by dividing the film into three separate regions. A general formulation is developed for a thin film flow, which then simplifies for each region upon considering appropriate assumptions to each region. The influence of inertia and surface tension in the presence of gravity is investigated …

Numerical Simulation Of Catalytic Ozone Decomposition Reaction In A Gas-Solids Circulating Fluidized Bed Riser, Lei Kong

Electronic Thesis and Dissertation Repository

Computational fluid dynamics (CFD) modeling of catalytic ozone decomposition reaction in a circulating fluidized bed (CFB) riser using iron impregnated FCC particles as catalyst is carried out. The catalytic reaction is defined as a one-step reaction with an empirical coefficient. Eularian-Eularian method with kinetic theory of granular flow is used to solve the gas-solids two-phase flow in the CFB riser. The simulation results are compared with experimental data, with the reaction rate modified using an empirical coefficient to provide better simulation results than the original reaction rate. Moreover, the particle size has great effects on the reaction rate. Studies on …