Engineering Commons^™

Flow And Thermal Effects Of Blockages In A Nano-Fluid Cooled Nuclear Fuel Subassembly, Shubham Mandot, N. Govindha Rasu

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Nanofluids have a great impact on heat transfer characteristics due to increased thermal conductivity and heat transfer coefficient. In this study, Titanium nanoparticles mixed in liquid sodium has been chosen for analyzing the effect of Nanofluid coolant for a Nuclear Sub- assembly. This study is conducted to observe the effect of nanoparticles on the flow properties and heat transfer characteristics such as velocity, heat transfer coefficient, clad temperature, coolant temperature etc. These effects have been observed for varying nanoparticle concentration and different flow blockage sizes. For this study, 7-pin fuel bundle with and without blockage has been modeled and analyzed …

Cfd Modeling Of Smoke Movement In An Atrium, Robin Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this paper is to better understand the behavior of smoke movement in an atrium. Thus gives first responders and civilians in and out of building a better understanding

With the advancements of modern technology, computers and softwares make simulation models possible such as fire models to simulate fire and smoke movements. In this paper, a computational fluid dynamic (CFD) software Fire Dynamic Simulator (FDS) is used to conduct a series of atrium tests to investigate the effectiveness of smoke exhaust systems. FDS solves the Navier-Stokes equations appropriate for low speed flows (Ma < 0.3) with an emphasis on smoke, heat transport and CO2 concentrations from fires. The default turbulence model used in FDS simulation is the Large Eddy Simulation (LES), which is the solution of Navier-Stokes equations at low speed.

The compartment tested was 9 …

Parametric Design And Optimization Of A Pivoting S-Type Rudder For Containerships, Chen-Wei Chen, Tsung-Yueh Lin, Bo-Yen Chen, Jen-Shiang Kouh

Journal of Marine Science and Technology

This study proposes an energy-saving S-type rudder design to deal with the inhomogeneous inflow from a rotating propeller behind a containership. The S-type rudder was modelled parametrically using four-digit NACA foils as section profiles together with Non-uniform rational B-splines (NURBS) surface formulations. A three-stage optimization process is proposed to reduce the number of design iterations necessary to achieve an optimal design. The propulsion simulations were done via CFD software, which solves the hydrodynamics of viscous flow, as governed by the Reynold-averaged Navier-Stokes (RANS) equations. Validations were performed with experimental model tests, including hull resistance, propeller open-water performance, and propulsion in …

Micro-Nozzle Simulation And Test For An Electrothermal Plasma Thruster, Tyler J. Croteau

Master's Theses

With an increased demand in Cube Satellite (CubeSat) development for low cost science and exploration missions, a push for the development of micro-propulsion technology has emerged, which seeks to increase CubeSat capabilities for novel mission concepts. One type of micro-propulsion system currently under development, known as Pocket Rocket, is an electrothermal plasma micro-thruster.

Pocket Rocket uses a capacitively coupled plasma, generated by radio-frequency, in order to provide neutral gas heating via ion-neutral collisions within a gas discharge tube. When compared to a cold-gas thruster of similar size, this gas heating mechanism allows Pocket Rocket to increase the exit thermal velocity …

Effect Of Aerogel On The Thermal Performance Of Corrugated Composite Sandwich Structures, Jacob Dillon Chess

Master's Theses

Current insulation solutions across multiple industries, especially the commercial sector, can be bulky and ineffective when considering their volume. Aerogels are excellent insulators, exhibiting low thermal conductivities and low densities with a porosity of around 95%. Such characteristics make aerogels effective in decreasing conductive heat transfer within a solid. These requirements are crucial for aerospace and spaceflight applications, where sensitive components exist among extreme temperature environments. When implemented into insulation applications, aerogel can perform better than existing technology while using less material, which limits the amount of volume allocated for insulation. The application of these materials into composites can result …

Investigating The Effect Of An Upstream Spheroid On Tandem Hydrofoils, Joel Tynan Guerra

Master's Theses

This thesis documents a series of three dimensional unsteady Reynolds Averaged Navier-Stokes CFD simulations used to investigate the influence of an upstream prolate spheroid body on tandem pitching hydrofoils. The model is validated by performing separate CFD simulations on the body and pitching hydrofoils and comparing results to existing experimental data. The simulations were run for a range of Strouhal numbers (0.2-0.5) and phase differences (0-π). Results were compared to identical simulations without an upstream body to determine how the body affects thrust generation and the unsteady flow field.

The combined time-averaged thrust increases with Strouhal number, and is highest …

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 …

A Computational Fluid Dynamics (Cfd) Analysis Of The Aerodynamic Effects Of The Seams On A Two-Dimensional Representation Of A Soccer Ball, Allen R. Rohr

Master's Theses

Most major sports today use a dedicated ball or projectile with specific shape, size, and surface geometry, except for soccer. Over the history of the sport, the surface geometry and design stayed relatively unchanged, sewn together using 32 pentagonal and hexagonal panels. However, recent innovations in panel designs differ substantially from the traditional 32 panel ball. The effects these new designs have on the aerodynamic characteristics of the ball have remained largely unknown, even with the influx of experimental research completed in the past decade. Experimental studies have been broad in scope, analyzing an entire ball in wind tunnels or …

Analysis Of The Effects Of Inlet Distortion On Stall Cell Formation In A Transonic Compressor Using Create-Av Kestrel, Mikkel Andreas Unrau

Theses and Dissertations

Accurately predicting fan performance, including bounds of operation, is an important function of any Computational Fluid Dynamics (CFD) package. The presented research uses a CFD code developed as part of the Computational Research and Engineering Acquisition Tools and Environment (CREATE), known as Kestrel, to evaluate a single stage compressor at various operating conditions. Steady-state, single-passage simulations are carried out to validate capabilities recently added to Kestrel. The analysis includes generating speedlines of total pressure ratio and efficiency, as well as radial total temperature and total pressure profiles at two axial locations in the compressor at various operating conditions and fan …

Wall Shear Stress In Simplified And Scanned Avian Respiratory Airways, Michael Sterling Farnsworth

Theses and Dissertations

Birds uniquely produce sound through a vocal organ known as a syrinx. The presence of wall shear stress acting on the airway cells of any organism will affect how airway cells develop and multiply. Unique features of avian airway geometry and breathing pattern might have contributed to the development of the syrinx. This thesis examines wall shear stress in the trachea and first bronchi of avian geometries using computational fluid dynamics. The computational fluid dynamic simulations underwent grid- and time-independence studies and were validated using particle image velocimetry. Parameters such as bird size, bronchial branching angle, and breathing waveform were …

Turbulent Mixers For Protein Folding Experiments, Venkatesh Inguva

Doctoral Dissertations

Protein folding studies require the development of micro-mixers that require less sample, mix at faster rates, and still provide a high signal to noise ratio. Chaotic to marginally turbulent micro-mixers are promising candidates for this application. In this study, various turbulence and unsteadiness generation concepts are explored that avoid cavitation. The mixing enhancements include flow turning regions, flow splitters, and vortex shedding. The relative effectiveness of these different approaches for rapid micro-mixing is discussed. Simulations found that flow turning regions provided the best mixing profile. Various turbulence models are simulated to determine appropriate model of the design requirements. Experimental validation …

Computational Exploration Of Flash-Boiling Internal Flow And Near-Nozzle Spray, Sampath K. Rachakonda

Doctoral Dissertations

Gasoline engines operating under the principle of direct injection are susceptible to flash-boiling due to superheated nature of the fuel and the sub-atmospheric in-cylinder pressures during injection. A review of the literature on flash-boiling sprays shows that a majority of the studies have focused on the far-field regions of the spray, with limited attention given to understanding the influences of the injector geometry and the near-nozzle regions of the spray. Modeling the internal nozzle flow and the primary atomization, on which the far-field spray depends, is a challenge. This thesis, therefore, is aimed at understanding the complex flow through a …

Liquid Jet Penetration And Breakup In A Free Supersonic Gas Jet, Hansen Jones

LSU Master's Theses

In the testing of today’s rocket engines, both on large scale vertical test stands and smaller subscale horizontal component testing stands, it is extremely important to be able to accurately quantify and mitigate the thermal and acoustic loads the engines will generate on test stand infrastructure. Due to the large number of parameters that must be considered for many cases, development of a multi-phase computational code is under way to properly analyze and design water spray cooling systems used at NASA’s Stennis Space Center (SSC) and across other NASA centers. As such, a small-scale experiment has been conducted at Louisiana …

Development And Application Of Rotation And Curvature Correction To Wray-Agarwal Turbulence Model, Xiao Zhang

McKelvey School of Engineering Theses & Dissertations

Computational Fluid Dynamics (CFD) is increasingly playing a significant role in the analysis and design of aircrafts, turbomachines, automobiles, and in many other industrial applications. In majority of the applications, the fluid flow is generally turbulent. The accurate prediction of turbulent flows to date remains a challenging problem in CFD. In almost all industrial applications, Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a turbulence model are employed for simulation and prediction of turbulent flows. Currently the one-equation (namely the Spalart-Allmaras (SA) and Wray-Agarwal (WA) and two-equation (namely the k-ε and Shear Stress Transport k-ω) turbulence models remain the most widely …

Numerical Investigations Of Bubble Column Equipped With Vertical Internals In Different Arrangements, Tuntun Gaurav

Electronic Thesis and Dissertation Repository

Bubble columns are multiphase contactors with wide applications in industrial processes. Often they are equipped with longitudinal tube bundles to facilitate heat exchange. Studying effects of these internals on column hydrodynamics is vital for the design of these internals. Computational Fluid Dynamic (CFD) simulations provide an understanding of the complex two-phase flow enabling the study of the effects of the internals on the column hydrodynamics. In the present work, an Eulerian-Eulerian based two-fluid model (TFM) coupled with a population balance model (PBM) is used to simulate the gas-liquid two-phase flows in bubble columns. The models studied were validated using experimental …

Computer Modeling Of Close-To-Ground Tornado Wind-Fields For Different Tornado Widths, Mohammadhossein Kashefizadeh

Graduate Theses and Dissertations

Tornadoes induce different wind forces on buildings than straight-line (SL) winds. The tangential velocity (Vθ) of tornados is the main parameter that causes damage to the buildings. In-field tornado measurements cannot evaluate the tornado’s Vθ at less than 20m above ground level (AGL). The laboratory tornado simulators suggest that the Swirl ratio (S) and the radius (ro) are the most influential factors affecting Vθ. However, due to scaling problems, laboratory simulators cannot report the Vθ for elevations less than 10m AGL. Well refined computational fluid dynamics (CFD) models can evaluate the Vθ at less than 10m AGL. However, the CFD …

Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi

Nima Fathi

Validation Of Cfd Simulations For Hypersonic Flow Over A Yawed Cone, Julian Cecil

McKelvey School of Engineering Theses & Dissertations

This study aims to numerically simulate the wind tunnel results for hypersonic flow over a circular cone of semi-apex angle of 10 degrees yawed from 0° to 20° using the commercial computational fluid dynamics software ANSYS Fluent. The ANSYS workbench is used to create the 10° semi-apex circular cone with a shock aligned structured mesh of 3.05 million cells surrounding the cone. Simulation boundary conditions for pressure and temperature in the far field correspond to Tracy’s wind tunnel experiment at Cal Tech. The six simulations cases are conducted for yaw angles of 0, 8, 12, 16, 20 and 24 degrees. …

Computational Fluid Dynamics Model For Air Velocity Through A Poultry Transport Trailer In A Holding Shed, Christian Heymsfield

Graduate Theses and Dissertations

Broiler production in Arkansas was valued at over $3.6 billion in 2013 (University of Arkansas Division of Agriculture Cooperative Extension Service). Consequently, improvement in any phase of the production process can have significant economic impact and animal welfare implications. One area of concern for the poultry industry is thermal stress experienced by the birds after arrival at the processing plant and before they are taken in to be processed, during which time they are left to wait in holding sheds. Various cooling strategies exist to mitigate heat stress in holding sheds, but in most cases it is unlikely that they …

Comparing Stenotic Blood Flow In Three- And Two-Dimensional Arterial Renderings Using Computational Fluid Dynamics And Multiphase Mean Age Theory., Jacob S. Garza

Electronic Theses and Dissertations

Over one million invasive coronary angiography procedures are performed annually in patients who experience chest pain or are known to have coronary artery disease. The procedure is carried out to ascertain the degree of arterial blockage (stenosis) that hinders blood flow to the heart. A cardiologist performing the procedure determines the physiological degree of a stenosis by either visual estimation, which is routine practice, or by invasively measuring fractional flow reserve (FFR), which is the current gold standard that has been demonstrated to improve patient outcomes and temper the cost of healthcare. Nevertheless, FFR is performed in only 10–20% of …

Immersive Visualization In Biomedical Computational Fluid Dynamics And Didactic Teaching And Learning, John Thomas Venn

Master's Theses (2009 -)

Virtual reality (VR) can stimulate active learning, critical thinking, decision making and improved performance. It requires a medium to show virtual content, which is called a virtual environment (VE). The MARquette Visualization Lab (MARVL) is an example of a VE. Robust processes and workflows that allow for the creation of content for use within MARVL further increases the userbase for this valuable resource. A workflow was created to display biomedical computational fluid dynamics (CFD) and complementary data in a wide range of VE’s. This allows a researcher to study the simulation in its natural three-dimensional (3D) morphology. In addition, it …

Investigation Of Microfluidic Kelvin Water Dropper And Its Applications In Contact And Contactless Electrowetting, Elias Yazdanshenas

Mechanical & Aerospace Engineering Theses & Dissertations

A typical Kelvin water dropper is a device that can convert gravitational potential energy to a high voltage electrostatic. This device consists of two inductors, two collectors, tubes, and electrical connections. A Kelvin water dropper is able to generate extremely high voltage by separating ions using two positive feedback loops. A Kelvin water dropper provides a low cost solution for the applications in which high voltage is needed. In the present research, low cost Microfluidic Kelvin Water Droppers (MKWDs) were developed and built in house for electrowetting applications. Two MKWDs with different tube inner diameters (254 and 508 μm) were …

Modeling And Validation Of Local Electrowinning Electrode Current Density Using Two Phase Flow And Nernst-Planck Equations, Joshua M. Werner, W. Zeng, M. L. Free, Z. Zhang, J. Cho

Mining Engineering Faculty Publications

In this work we demonstrate the validity of a multi-physics model using COMSOL to predict the local current density distribution at the cathode of a copper electrowinning test cell. Important developments utilizing Euler-Euler bubbly flow with coupled Nernst-Planck transport equations allow additional insights into deposit characteristics and topographies.

Understanding The Effect Of Extrusion Processing Parameters On Physical, Nutritional And Rheological Properties Of Soy White Flakes Based Aquafeed In A Single Screw Extruder, Sushil Kumar Singh

Sushil Singh

The rapid expansion of aquaculture has increased the demand for aquafeed. As fishmeal is expensive, alternative plant based protein sources such as soybean has shown to be a good alternative for aquafeed production. The present study was done to investigate the effect of soy white flakes (SWF) as an alternative source of protein in the production of aquaculture feed through extrusion processing. Ingredient blends containing different levels of SWF along with distiller dried grains, corn flour, corn gluten meal, fish meal, vitamin and mineral mix with net protein adjusted to 32% protein were formulated. The ingredient blends were extruded in …

Low Reynolds Number Numerical Simulation Of The Aerodynamic Coefficients Of A 3d Wing, Khurshid Malik, Waqar Asrar, Erwin Sulaeman

International Journal of Aviation, Aeronautics, and Aerospace

A low Reynolds number, three-dimensional CFD analysis is carried out for a finite flat plate wing using the commercial CFD code STAR CCM+. The six-aerodynamic force and moment components C_L, C_D, C_M, C_N, C_l, C_Y and their derivatives are computed at a Reynolds numbers of 3x10⁵ by varying the pitch, roll and yaw angles about the quarter chord point. The computed results have been validated with experimental aerodynamic balance data when possible. The results indicate that roll and yaw angle affect the aerodynamic coefficients of the flat plate …

A Cfd Assisted Closed-Loop Control System Design For The 37-Element Canadian Scwr Under Full Load Condition, Huirui Han

Electronic Thesis and Dissertation Repository

A method to design the closed-loop control system for the 37-element vertical Canadian supercritical water-cooled reactor (SCWR) fuel bundle has been proposed in this study. The dynamic models used in the controller design are obtained based on the computational fluid dynamics (CFD) simulations of the fluid flow and heat transfer of the supercritical water in the SCWR fuel bundle. The Reynolds Stress Model is used in the CFD simulations. Comparisons of the supercritical water flow behaviors and heat transfer phenomenon in the single- rod channel and multi-rod channel are also carried out. The results show that there are secondary flows …

Cfd/Fea Of A Steam Methane Reforming Tube, Matthew Wegener

Research Opportunities for Engineering Undergraduates (ROEU) Program 2017-18

Steam methane reforming is the primary method by which hydrogen is produced; increased efficiency in hydrogen production could enable hydrogen’s usage as an alternative fuel. The objectives of this project are to construct a robust CFD/FEA model of a steam methane reforming tube, and to perform CFD/FEA analysis in both steady and transient operational states, comparing thermal stresses/strains in the tube wall in the two states and relating tube stresses/strains to properties of the process controller.

Cardiovascular Biomechanical Models, Ethan Kung

Publications

Computational and in vitro methods offer powerful means to model the cardiovascular system and investigate biomechanics related to blood flow, cardiovascular tissue, and medical devices. These models can be constructed to directly describe human anatomy and physiology, and can be more highly controlled compared to animal models. Low-order models composed of lumped-parameter elements and simplified descriptions of cardiac function can capture the global physiology, while high-order models exhibiting detailed 3D anatomy and dynamics can provide highly realistic replication of biomechanical interactions in a small region of the circulation. Multiscale models offer the freedom to capture biomechanics in different regions at …

An Experimental And Computational Study Of Fuel Spray Interaction: Fundamentals And Engine Applications, Le Zhao

Dissertations, Master's Theses and Master's Reports

An efficient spray injection results in better vaporization and air-fuel mixing, leading to combustion stability and reduction of emissions in the internal combustion (IC) engines. The impingement of liquid fuels on chamber wall or piston surface in IC engines is a common phenomenon and fuel film formed in the spray-piston or cylinder wall impingement plays a critical role in engine performance and emissions. Therefore, the study of the spray impingement on the chamber wall or position surface is necessary.

To understand the spray-wall interaction, a single droplet impingement on a solid surface with different conditions was first examined. The droplet-wall …

Hydrodynamics Related Performance Evaluation Of Upflow Moving Bed Hydrotreater Reactor (Mbr) Using Developed Experimental Methods And Cfd Simulation, Vineet Alexander

Doctoral Dissertations

"Upflow Moving Bed Hydrotreater (MBR) reactor is used for hydrotreating resid crude oil. It is a two-phase upflow reactor having a catalyst bed with conical bottom, and plena. At industrial conditions the reactor is not performing at its best and encountering issues such as hot spots, catalyst agglomeration inside the catalyst bed leading to frequent shutdown of the reactor. The root cause of these problems are linked to the improper hydrodynamics inside the catalyst bed. To investigate this, the industrial scale MBR is scaled down to a pilot scale and indicative and key hydrodynamic parameters are investigated using developed experimental …