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Investigation Of Thermofluid Processes In A Pcm Based Thermal Storage Module, Luca M. Crnjac

Electronic Thesis and Dissertation Repository

Latent heat thermal energy storage systems can capture and store solar thermal energy, enhancing the reliability of solar energy by facilitating a continuous and consistent energy supply. However, phase change materials used in these systems suffer from low thermal conductivities making it difficult to achieve suitable charging and discharging rates. The present research investigated this issue using computational and experimental approaches to improve the design of a thermal storage module through heat transfer enhancement. Various heat transfer enhancements including a finned honeycomb structure, and metal wool were incorporated into a thermal storage module to analyze their effect on charging and …

An Optimization Procedure To Design Nozzle Contours For Hypersonic Wind Tunnels, Omar Antonio Dominguez

Open Access Theses & Dissertations

Supersonic wind tunnels allow scientists and researchers to evaluate and analyze the behaviors of objects under real-life conditions when subjected to supersonic speeds. One of the main complexities when building a wind tunnel is the design of the convergent-divergent nozzle that is used to produce high-speed and high-quality flows. To achieve supersonic speeds, this nozzle adopts a specialized approach that incorporates the complexities of flow compressibility. The compressible effect is accurately evaluated using isentropic relations, allowing for precise determination of stagnation pressure and temperature, and static pressure and temperature relevant to the desired Mach number. Isentropic equations used to define …

Computational Analysis Of Water Braking Phenomena For High-Speed Sled And Its Machine Learning Framework, Jose A. Terrazas

Open Access Theses & Dissertations

Specializing in high-speed testing, Holloman High-Speed Test Track (HHSTT) uses a process called "water braking" as a method to bring vehicles at the test track to a stop. This method takes advantage of the higher density of water, compared to air, to increase braking capability through momentum exchange. By studying water braking using Computational Fluid Dynamics (CFD), forces acting on track vehicles can be approximated and prepared for prior to the actual test. In this study, focus will be made on the brake component of the track sled that is responsible for interacting with the water for braking. By discretizing …

Multidimensional Transport-Coupled Numerical Investigation Of Non-Premixed Low-Temperature Flame In Atmospheric And High-Pressure Systems, Sudipta Saha

Theses and Dissertations

Gas-phase chemical reactions coupled with multidimensional fluid flow and heat and mass transport are found in various applications, i.e., from conventional engine applications to novel combustion techniques. With the goal of understanding such complex coupling in reacting flow systems, this dissertation work focuses on developing multi-physics simulation frameworks to investigate the effect of multidimensional transport on flame dynamics. This study primarily focuses on the modeling and simulation of low temperature flame formation in i) a canonical experimental setting with counterflow burners and ii) a supercritical water medium (i.e., hydrothermal flame).

In the first part of the dissertation, simulations of the …

Modeling Of Transport In Anatomic Respiratory Airways: Applications In Targeted Drug Delivery And Airborne Pathogenic Transmissions, Mohammad Mehedi Hasan Akash

Electronic Theses and Dissertations

This thesis aims to explore the potential of improving the efficacy of drugs for treatment of viral infections by targeting the nasopharynx, which is commonly the first site of infection for many viral pathogens. Currently, intranasal sprays are used, but the standard protocol (“Current Use” or CU) results in suboptimal drug deposition at the nasopharynx. To address this issue, an “Improved Use” or, IU protocol has been proposed, which involves pointing the spray bottle at a shallower angle and aiming slightly towards the cheeks. The IU delivery is also robust to perturbations in spray direction, which highlights the practical utility …

On The Simulation Of Supersonic Flame Holder Cavities With Openfoam, Zachary Chapman

Electronic Theses and Dissertations

One of the next major advancements in the aerospace industry will be hypersonic flight. However, to achieve hypersonic flight, propulsion systems capable of reaching hypersonic speeds need to be developed. One of the more promising hypersonic propulsion systems is the scramjet engine, however, several problems still need to be explored before reliable scramjet engines can be produced, the biggest being keeping the engine ignited. This has led to the use of flame holder cavities to create a region of subsonic flow within the engine to allow combustion to occur. High experimental costs make the use of computational fluid dynamic (CFD) …

Numerical Investigation Of Flow And Thermal Behavior In Channels With Pcm-Filled Thermal Energy Storage Columns For Potential Application In Photobioreactors, Sameed Akber

Electronic Thesis and Dissertation Repository

Microalgae has been identified as a potential source in the production of biofuel. Photobioreactors, which are used for microalgae production, normally experience temperature variations over the diurnal cycle due to changes in ambient conditions. The thermal regulation of photobioreactors to minimize temperature variations will result in a higher yield of microalgae, which are sensitive to such variations. The present research is aimed to investigate a novel approach to thermally regulate photobioreactors using phase change materials (PCM) where the latent heat of the material is exploited as the energy storage. The present research uses a numerical approach to study the flow …

Pressure Disturbance Upstream Of The Boundary Layer Data System, Michelle S. Leclere

Master's Theses

The primary objective for this work was to evaluate the reliability of computational fluid dynamics (CFD) tools in the prediction of upstream surface pressure disturbance and pressure drag of various instrument excrescence shapes for a small aircraft flight test device called the Boundary Layer Data System (BLDS). Insights on pressure disturbance will serve as a guide for the placement of BLDS probes/sensors, and pressure drag can be used to ensure sufficient adhesive is used to install BLDS instrumentation. The Mach number for all CFD cases was 0.12 and the Reynolds number based on excrescence height varied from 4 x 10 …

Numerical Modeling Of Advanced Propulsion Systems, Peetak P. Mitra

Doctoral Dissertations

Numerical modeling of advanced propulsion systems such as the Internal Combustion Engine (ICE) is of great interest to the community due to the magnitude of compute/algorithmic challenges. Fuel spray atomization, which determines the rate of fuel-air mixing, is a critical limiting process for the phenomena of combustion within ICEs. Fuel spray atomization has proven to be a formidable challenge for the state-of-the-art numerical models due to its highly transient, multi-scale, and multi-phase nature. Current models for primary atomization employ a high degree of empiricism in the form of model constants. This level of empiricism often reduces the art of predictive …

Predictive Model Of Air Dam Deflection Under Aerodynamic Loads, Chang Kyun Kang

Electronic Theses and Dissertations

Plastic components are widely used on the exterior body of automotive vehicles. When the vehicle is moving, these components experience deformation caused by air flow. Simultaneously, the deformation affects the flow of air around the vehicle. This research is focused on developing virtual simulation techniques for determining the vehicle air dam behaviour under aerodynamic loads. The main objective of this research is to develop a fluid-structure interaction (FSI) methodology for predicting deflection of the air dam.

Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) codes are coupled so that fluid pressure and air dam displacement parameters are exchanged. The …

Numerical Modeling Of The Fiber Deposition Flow In Extrusion-Based 3d Bioprinting, Dhanvanth Jaya Talluri

Theses and Dissertations

Extrusion bioprinting involves the deposition of bioinks in a layer-wise fashion to build 3D structures that mimic natural living systems' behavior in tissue engineering. Hydrogels are the most common bioinks, in which their viscosity properties are dependent on the shear-rate, such as Non-Newtonian fluids. Numerical simulation of extrusion bioprinting may help study the flow properties of hydrogels and designing improved bioinks. In this thesis, the instability caused by the shear-thinning or -thickening parameter during extrusion is numerically compared with the theoretical estimations. The process of fiber deposition of hydrogels onto a substrate through the single and coaxial nozzle is done …

Assessing The Effectiveness Of Cfd To Solve An Inverse Problem Of Thermal Profiles For The Protodune-Sp Neutrino Detector, Cecilia Anne Streff

Electronic Theses and Dissertations

Computational fluid dynamics (CFD) is a branch of fluid mechanics which is employed to numerically solve complex fluid, heat transfer, and multiphysics problems. Traditionally, CFD techniques are used to solve “forward” problems—using some known information of a system as inputs to a representative model to predict experimental measurements or expected system behavior. The work presented here demonstrates how CFD may be used to solve an “inverse” problem—given limited experimental data and some model, predict (previously unidentified) “input” system (or system model) parameters. The case study for this research uses a validated CFD modeling approach of the liquid argon (LAr) region …

The Stability Of Two-Dimensional Cylinder Wakes In The Presence Of A Wavy Ground, Matt Duran

Honors Undergraduate Theses

The following study investigates hydrodynamic stability for two-dimensional, incompressible flow past a cylinder and compares it alongside four different variations of a wave-like ground introduced within the wake region of the cylinder wake. These different variations include changing the distance of the cylinder both horizontally from the wave-like structure and vertically from the ground. The geometry and meshes were initially constructed using GMSH and imported into Nektar++. The baseflows were then obtained in Nektar++ using the Velocity Correction Scheme, continuous Galerkin method, and Unsteady Navier Stokes solver. Then, the Implicitly Restarted Arnoldi Method driver was used to retrieve the various …

Numerical Investigation Of Flow Around A Deformed Vacuum Lighter-Than-Air Vehicle, Jared N. Kerestes

Browse all Theses and Dissertations

This study characterizes the functional dependence of drag on Reynolds number for a deformed vacuum lighter-than-air vehicle. The commercial computational fluid dynamics (CFD) code, FLUENT, is used to preform large eddy simulations (LES) over a range of Reynolds numbers; only Reynolds numbers less than 310,000 are considered. While the overarching goal is drag characterization, general flow-field physics are also discussed, including basic turbulence spectra. All large eddy simulations are preceded by a Reynolds-averaged Navier-Stokes (RANS) simulation using Menter’s shear stress transport (SST) model. The precursor RANS simulation serves to (1) provide realistic initial conditions, (2) decrease the time needed to …

The Effect Of K2co3 Concentration In Kerosene Emulsions On Spray Droplet Sizes For A Magnetohydrodynamic Power Generator, Alejandra Castellano

Open Access Theses & Dissertations

Potassium carbonate (K2CO3) is an effective seeding material to introduce potassium vapor in oxy-fuel combustion to create a conductive plasma. Injecting potassium carbonate before combustion promotes particle volatilization and improves the generation of potassium vapor. This can be achieved by emulsifying a potassium carbonate solution with kerosene. Several studies have investigated creating stable emulsions with kerosene with water by using differing surfactants. However, the effects of using varying concentrations of K2CO3 dissolved in deionized water have not been fully explored. Based on methods of creating successful emulsions, the development of a successful mixture comprised of kerosene and K2CO3 solution is …

Machine Learning Analysis To Characterize Phase Variations In Laser Propagation Through Deep Turbulence, Luis Fernando Rodriguez Sanchez

Open Access Theses & Dissertations

The present Dissertation is focused on the analysis of the atmospheric conditions of a turbulent environmental system and its effects on the diffraction of a laser beam that moves through it. The study is based on the optical communication of two labs placed at the summit of two mountains located in Maui, Hawaii. The emitter system is located at the Mauna Loa mountain and the receiver at the Haleakala. The distance between both mountains is 150 km. The emitter system is at a height of 3.1 km and the receiver at 3.4 km. The maritime environment at the location experiences …

Development Of Horizontal Axis Hydrokinetic Turbine Using Experimental And Numerical Approaches, Abdulaziz Abutunis

Doctoral Dissertations

“Hydrokinetic energy conversion systems (HECSs) are emerging as viable solutions for harnessing the kinetic energy in river streams and tidal currents due to their low operating head and flexible mobility. This study is focused on the experimental and numerical aspects of developing an axial HECS for applications with low head ranges and limited operational space. In Part I, blade element momentum (BEM) and neural network (NN) models were developed and coupled to overcome the BEM’s inherent convergence issues which hinder the blade design process. The NNs were also used as a multivariate interpolation tool to estimate the blade hydrodynamic characteristics …

Using Computational Fluid Dynamics To Accurately Model Agricultural Spray Nozzles, Zachary Chapman

Electronic Theses and Dissertations

Computational fluid dynamics (CFD) is a tool used by engineers in many industries to study fluid flow. A relatively new industry to adopt the use of CFD is the agricultural industry. The present work seeks to understand whether CFD can be used to accurately model spray nozzles. A spray nozzle commonly used in agricultural spraying was simulated. First, the impact of factors such as mesh size, mesh type, and physics models have on the solution were investigated. Next, a method to pulse the spray was determined. This was required to compare simulation results with experimental data. A user-defined function was …

Computational Fluid Dynamics Models Of Electromagnetic Levitation Experiments In Reduced Gravity, Gwendolyn Bracker

Masters Theses

Electromagnetic levitation experiments provide a powerful tool that allows for the study of nucleation, solidification and growth in a containerless processing environment. Containerless processing allows for the study of reactive melts at elevated temperatures without chemical interactions or contamination from a container. Further, by removing the interface between the liquid and its container, this processing technique allows for greater access to the undercooled region for solidification studies. However, in these experiments it is important to understand the magnetohydrodynamic flow within the sample and the effects that this fluid flow has on the experiment.

A recent solidification study found that aluminum-nickel …

Transient Flow Analysis Of A Closing Blowout Preventer Using Computational Fluid Dynamics (Cfd), Daniel Barreca

LSU Master's Theses

Reliability of blowout preventers (BOPs) is crucial for drilling and production operations. Erosion of BOP components and hydrodynamic forces on rams may cause failure of BOP elements to seal the well. Transient computational fluid dynamics (CFD) simulations of fluids within the wellbore and BOP offer quantitative and qualitative data related to this reliability during the closure of various BOP components. Since limited research has been published in transient CFD simulations of closing BOPs, this thesis discusses challenges and solutions to simulating closing blowout preventers. Single component fluids are simulated through several BOP geometries such as annular preventers, pipe rams, and …

Examination Of Flow Dynamics And Passive Cooling In An Ultra Compact Combustor, Tylor C. Rathsack

Theses and Dissertations

The Ultra Compact Combustor (UCC) promises to greatly reduce the size of a gas turbine engine’s combustor by altering the manner in which fuel is burnt. Differing from the common axial flow combustor, the UCC utilizes a rotating flow, coaxial to the engine’s primary axis, in an outboard circumferential cavity as the primary combustion zone. The present study investigates two key UCC facets required to further this combustor design. The first area of investigation is cooling of the Hybrid Guide Vane (HGV). This UCC specific hardware acts as a combustor center body that alters the exit flow angle and acts …

Quantifying The Performance Of The Protodune Single Phase Neutrino Detector Using Computational Fluid Dynamics, Dillon Pedersen

Electronic Theses and Dissertations

The goal of this research is to provide scientifically-valid computationally generated data of the flow, thermal, and impurity data of the ProtoDUNE single phase detector. Results are compared and validated against an actual detector that is currently being utilized to collect temperature and impurity data. This research will investigate the flows inside these detection chambers using computational fluid dynamics to find approximate solutions to the governing equations of fluid mechanics. Impurity and flow data will allow researchers to determine if results collected are being obstructed by high levels of impurity. Novel approaches have been developed to strike a balance between …

Fluid Agitation Studies For Drug Product Containers Using Computational Fluid Dynamics, Matthew Hiroki Ichinose

Master's Theses

At Amgen, the Automated Vision Inspection (AVI) systems capture the movement of unwanted particles in Amgen's drug product containers. For quality inspection, the AVI system must detect these undesired particles using a high speed spin-stop agitation process. To better understand the fluid movements to swirl the particles away from the walls, Computational Fluid Dynamics (CFD) is used to analyze the nature of the two phase flow of air and a liquid solution.

Several 2-D and 3-D models were developed using Fluent to create simulations of Amgen's drug product containers for a 1 mL syringe, 2.25 mL syringe, and a 5 …

Simulation Of Radiation Flux From Thermal Fluid In Origami Tubes, Robert R. Bebeau

USF Tampa Graduate Theses and Dissertations

Spacecraft in orbit experience temperature swings close to 240 K as the craft passes from the shadow of the Earth into direct sunlight. To regulate the craft’s internal energy, large radiators eject unwanted energy into space using radiation transfer. The amount of radiation emitted is directly related to the topology of the radiator design. Deformable structures such as those made with origami tessellation patterns offer a mechanism to control the quantity of energy being emitted by varying the radiator shape. Three such patterns, the Waterbomb, Huffman Waterbomb, and Huffman Stars-Triangles, can be folded into tubes. Origami tubes offer greater control …

A Mathematical Model For Predicting Rotating Belt Filter Performance, Anthony Sherratt

Electronic Thesis and Dissertation Repository

Increased demand on wastewater treatment plants has motivated the development of new primary wastewater treatment techniques. Rotating belt filters (RBF) offer a spatially compact and lower cost solution. The goal of the present work is to develop a model that accurately predicts the flow rate capacity and removal efficiency of a generic RBF. Mesh resistance will be characterized using an idealized computational fluid dynamics (CFD) model of the mesh filter used in an RBF. To characterize the cake resistance, a gravity drainage column test was modeled and using the results from the CFD model, the cake resistance versus filtered volume …

Implementing Large Eddy Simulation To Numerical Simulation Of Optical Wave Propagation, Diego Alberto Lozano Jimenez

Open Access Theses & Dissertations

In this study, we want to simulate long-range laser propagation in atmospheric turbulence. The numerical simulations are carried out to study the impact of strong atmospheric turbulence in spatial, temporal, and related spectral domains. The first section of this study will be concerned with modeling this numerical simulation in Kolmogorov and non-Kolmogorov spectrum. To validate our numerical simulation, we will compare the statistical parameter to theoretical approximation in both Kolmogorov and non-Kolmogorov spectrums. Once the code is validated, we want to integrate Large Eddy Simulation (LES) turbulence modeling. LES simulations allowa us to study strong fluid turbulence and can predict …

Data-Driven Predictive Framework For Modeling Complex Multi-Physics Engineering Applications, Arturo Schiaffino Bustamante

Open Access Theses & Dissertations

Computational models are often encountered in multiple engineering application, such as structural design, material science, heat transfer and fluid dynamics. These simulations offer the engineers the capability of understanding complex physical situations before putting them to practice, either through experimentation or prototyping. The current advances in computational sciences, hardware architecture, software development and big data technology, have allowed the construction of sturdy predicting frameworks for analyzing a wide array of natural phenomena across different disciplines, either through the implementation of statistical methods, such as big data, and uncertainty quantification, or through high performance computing of a numerical model. The objective …

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …

A Comparison Of The Aerodynamic Centers For Panel Code Compressible Corrections And Openfoam 5 For Mach 0.1 To 0.8, Dustin Weaver

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

It is known that the aerodynamic center changes from quarter chord to half chord from incompressible to compressible flows on airfoils. Compressible corrections are derived and implemented in a vortex panel code. These results will be used to find the aerodynamic centers for the specified Mach range of 0.1 to 0.8 in 0.1 increments within - 6 to 6 degrees angle of attack. OpenFOAM 5 cases will be created with specific meshes and settings. The results calculated from OpenFOAM 5 will be compared to the results obtained from the compressible corrections.

A Computational Fluid Dynamics Study On Bidirectional Glenn Shunt Flow With An Additional Pulsatile Flow Through A Modified Blalock-Taussig Shunt, Seda Aslan

University of New Orleans Theses and Dissertations

The blood flow through the Bidirectional Glenn shunt (BGS) and modified Blalock-Taussig shunt (mBTS) to the pulmonary arteries (PAs) was analyzed using Computational Fluid Dynamics. This study consisted of the steady and pulsatile cases. In case one, the results of blood flow through the BGS for the Newtonian and non-Newtonian viscosity models were compared. Case two focused on having an additional pulsatile blood flow through the mBTS using the non-Newtonian Carreau viscosity model. The geometries were created based on the angiograms. In case one, boundary conditions to be specified at the inlets were obtained from the flow rate measurements via …