Transport Phenomena Commons^™

Anion Exchange Membrane Transport And Accelerated Testing Methods For Co2 Electrolyzers With Cu-Based Electrocatalyst, John C. Hendershot

LSU Doctoral Dissertations

Electrocatalytic carbon dioxide (CO₂) reduction to C₂₊ products holds promise for low carbon intensity fuels, chemicals, and food; however, durability challenges, particularly bicarbonate (HCO₃^-)and carbonate (CO₃^2-) salt precipitation, hinder their commercialization. This report considers water (H₂O) and ion transport properties of conventional anion exchange membranes (AEMs) in zero-gap membrane electrode assembly (MEA) configurations using Cu electrocatalysts. Transport characterization includes H₂O diffusion, permeability, potassium (K⁺) diffusion, and transference numbers using three commercial AEMs, including piperidinium-based (Versogen), quaternary ammonium-based (Fumasep), and imidazolium-based (Dioxide Materials) membranes. Accelerated lifetime …

Statistical Investigation Of Gypsum Crystallization Kinetics, Azmain A. Akash

LSU Master's Theses

Gypsum, a naturally occurring mineral salt, is frequently encountered in industrial processes such as seawater desalination and power plant cooling. Over the years, significant effort has been devoted to controlling the crystallization of gypsum through various chemical approaches, including acidification, chelating agents, and antiscalant polymers. Nevertheless, the cost associated with chemical treatments may be reduced by incorporating physical operational strategies to complement chemical methods in regulating gypsum crystallization.

This study systematically examines the comparative roles of chemical and physical entropy in the gypsum crystallization process to elucidate their respective influences on gypsum growth kinetics. Chemical entropy is manipulated by adjusting …

Electric Field Driven Co-Assembly And Transport Of Colloids Using Active-Passive Interaction, Brishty Deb Choudhury

LSU Master's Theses

Over the past few decades, the out-of-equilibrium transport and assembly of colloidal particles have been drawing significant interest due to their myriad applications in biology, engineering, and physics. In the absence of any external force, micro and nanoparticles perform Brownian motion in dispersion and are termed as passive colloids. In contrast, active colloids are a class of particles where a net imbalance of fluid flow around their surface drives their net migration in space when subjected to an external electric field. While several studies have shown the ability to program the dynamics of active colloids using an external electric field, …

Tuning Electrochemical Interactions And Polymer Electrolyte Interfaces For Enhanced Organic Acid Separations Using Electrodeionization, Matthew Leo Jordan

LSU Doctoral Dissertations

Chemical separations are critical processes for chemical and industrial plants to purify and isolate products however current separation technologies, such as distillation, rely on energy intensive processes. Electrochemical separation processes, such as electrodialysis and electrodeionization, are an energy efficient alternative that are emerging as an alternative for thermal-based separations. Organic acids are weakly ionizable species and susceptible for purification from process streams using electrochemical processes. Recently the fermentation route has garnered greater attention as a means for producing value-added chemicals, such as organic acids, from a renewable feedstock and aiding the circular economy. Some of the challenges electrodialysis faces for …

Cfd Simulations Of Macroscopic And Microscopic Multiphase Fluid Flow And Droplet Interaction, Aaron Harrington

LSU Master's Theses

Multiphase flow is a complex phenomenon which can be modeled on numerous different length scales, both macroscopically and microscopically. The use of a Euler-Euler model for Computation Fluid Dynamics (CFD) simulations of subcooled boiling phenomena is discussed in detail. The CFD conditions have been set up to mimic previous experimental conditions. A cylindrical vessel with subcooled liquid flow is heated along part of the axial wall of the vessel. A constant heat flux is applied to produce subcooled boiling. We discuss the development of the phase change within the vessel as well as the temperature profile, and validate the results …

The Desorption Kinetics Of Methane From Nonaqueous Fluids For Enhanced Well Control, James Lee Nielsen Jr.

LSU Master's Theses

The mass transfer of a dissolved gas evolving to return to the gaseous phase from a liquid is governed by many parameters. This process affects the development of an oil and gas well due to the possibility of gas contamination occurring from either an influx entering the wellbore, or drilling through gas-bearing formations. Once this dissolved hydrocarbon gas circulates up the wellbore, it will begin to evolve from solution and poses a potential risk to drilling equipment, the environment, and personnel at a drilling rig. Being able to predict the behavior of gas desorption based on a known set of …

A Study Of Particle-Laden Flows From Meso And Micro-Scale Perspectives, Daniel Guedes De Oliveira

LSU Doctoral Dissertations

Particle-laden flows are investigated numerically from a meso-scale perspective using Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) and from a micro-scale perspective using Particle Resolved Direct Numerical Simulation (PR-DNS). For the former, the dynamics of a pseudo-2D pulsed fluidized bed (PFB) consisting of 400,000 to 800,000 particles was investigated (Chapters 2 and 3). The focus is on the capabilities of CFD-DEM to (1) reproduce pattern formation in these systems and (2) further the understanding of the dynamics of PFB's as a function of pulsation parameters. In Chapter 4, a two-spheres system is investigated with a recently implemented PR-DNS …

Breaking Coastal Hypoxia: Destratification Of Gulf Of Mexico Deadzone To Encourage Oxygen Transport Downwards To Maintain Marine Fauna, Veda Thipparthi

LSU Master's Theses

As a consequence of seasonal eutrophication and human input, a vast hypoxic area termed The Dead Zone develops every year in the Gulf of Mexico (GOM) during summer along the Louisiana coastline characterized by vertical seawater density-stratification with oxygen concentrations less than 2 mg.l^-1 at the seafloor. It poses a threat to bottom-dwelling faunae and their environment which has negative ecological and economic consequences. This project aims to mitigate hypoxia by employing mechanical impellers placed at strategic water depths and locations in the Gulf. Enhanced transport of oxygen results by mixing oxygen-enriched seawater at the surface, downward into the …

Multiphase Cfd Modeling In Particle-Laden Flows, Zhizhong Ding

LSU Doctoral Dissertations

Multiphase modeling is prevalent and useful in solving problems involving multiphase interactions such as fluid and solid. Applications conclude but not limited to fluidized bed, hydraulic conveying, and many others. Modeling techniques with multiple scales can provide various states of details with diverse computational resources used. In this dissertation, two CFD multiphase models are used to disclose interaction details in the particulate system. Two-Fluid Model is used to solve pulsed fluidized bed problem and immersed boundary method based direct numerical method is used to solve particle’s behavior in shear flow. Getting a better understanding of these problems to help to …

Experimental And Numerical Investigation Of Liquid-Assisted Gas-Lift Unloading, Renato Peixoto Coutinho

LSU Doctoral Dissertations

The case for a unique form of gas-lift unloading, termed “Liquid-Assisted Gas-Lift (LAGL),” is presented. This work demonstrates that the injection of a gas-liquid mixture allows transport of gas to a deep injection point utilizing injection pressure considerably lower than single-phase gas injection. The LAGL is demonstrated in a 2,880 ft deep test well. The test well is kicked-off using an injection pressure that would normally be lower than the pressure for single-point single-phase gas injection at this depth. Experimental results indicate that the LAGL can lower the injection pressure by up to 75%.

This work breaks the LAGL system …

Mobility Of Nano-Particles In Rock Based Micro-Models, Jagannath Upadhyay

LSU Doctoral Dissertations

A confocal micro-particle image velocimetry (C-μPIV) technique along with associated post-processing algorithms is detailed for obtaining three dimensional distributions of nano-particle velocity and concentrations at select locations of the 2.5D (pseudo 3D) Poly(methyl methacrylate) (PMMA) and ceramic micro-model. The designed and fabricated 2.5D micro-model incorporates microchannel networks with 3D wall structures with one at observation wall which resembles fourteen morphological and flow parameters to those of fully 3D actual reservoir rock (Boise Sandstone) at resolutions of 5 and 10 μm in depth and 5 and 25 μm on plane. In addition, an in-situ, non-destructive method for measuring the geometry of …

Pore-Scale Analysis Of Interfacial Instabilities And Impact Of Heterogeneity On Relative Permeability By Lattice Boltzmann Method, Zhipeng Zhu

LSU Master's Theses

Interfacial instabilities occur often during immiscible fluid flow through porous media and their understanding is essential for waterflooding operations or other oil recovery processes. Although many studies including experimental and numerical have been done to reproduce and analyze the interfacial instabilities in porous median, there is still significant knowledge gap in fundamental understanding of these flow instabilities at the pore-scale. In order to better understand the interfacial instabilities phenomenon, the pore-scale simulations are performed. In this study, Lattice Boltzmann Method is used to simulate two different types of interfacial instabilities: viscous fingering and capillary fingering in irregular sphere packs by …

Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam

LSU Doctoral Dissertations

The application of the Euler-Euler framework based Computational Fluid Dynamics (CFD) models for simulating the two-phase gas-liquid bubbly flow in down-flow bubble columns is discussed in detail. Emphasis is given towards the modelling and design optimization of a novel down-flow bubble column. The design features of this novel down-flow bubble column and its advantages over a conventional Plunging Jet down-flow bubble column are discussed briefly. Then, some of the present challenges in simulating a conventional Plunging Jet down-flow bubble column in the Euler-Euler framework is highlighted, and a sigmoid function based drag modification function is implemented to overcome those challenges. …