Engineering Commons^™

Using Numerical Modeling To Determine Viscous Losses Within Helium Turbomachinery, Benjamin Uhlig

Mechanical and Aerospace Engineering Theses

As the consumption of energy has increased relentlessly over the last few decades, the need for reliable clean energy generation has increased as well. Currently, nuclear power is the only method capable of providing a stable supply of clean energy, although the nuclear energy generation process still requires improvement. Specifically, there is a need to increase efficiencies while reducing the risks of radioactive contamination. It is possible that both these issues may be mitigated using helium as the working fluid. However, the performance of turbomachinery using helium must be evaluated before its use can be implemented. To do this, Balaji …

Development Of A Pediatric Cardiac Assist Maglev Pump For Use With A Universal Driver System., Landon Heath Tompkins

Electronic Theses and Dissertations

Heart failure (HF) remains the leading cause of death, affecting 26 million adults worldwide and 6.5 million adults in the United States. Pediatric HF patients have been a historically underserved population with few options for mechanical circulatory support (MCS) therapy, a leading treatment as an alternative to heart transplantation. To address this clinical need, the Inspired Universal MagLev System is being developed; a low cost, universal magnetically levitated extracorporeal MCS system with interchangeable single-use pumps that will ultimately provide adult and pediatric patients ventricular and respiratory assist therapies. The Inspired Pediatric VAD is the first single-use pump application for this …

Analytical And Computational Modelling Of The Ranque-Hilsch Vortex Tube, Nolan J. Dyck

Electronic Thesis and Dissertation Repository

The Ranque-Hilsch vortex tube (RHVT) is a simple mechanical device with no moving parts capable of separating a supply of compressed fluid into hot and cold streams through a process called temperature separation. The overall aim is to develop models which can be used to assess the temperature separation mechanisms in the RHVT, leading to a better overall understanding of the underlying physics. The introductory chapter contains a thermodynamic analysis and introduction to the flow physics, alongside three miniature literature reviews and critiques identifying research gaps.

The body of the thesis contains three articles. The first article studies the flow …

Design Of A Methanol Reformer For On-Board Production Of Hydrogen As Fuel For A 3kw High-Temperature Proton Exchange Membrane Fuel Cell Power System, Vladimir Gurau, Adedayo Ogunleke, F. Strickland

Department of Manufacturing Engineering Faculty Research and Publications

The method of Computational Fluid Dynamics is used to predict the process parameters and select the optimum operating regime of a methanol reformer for on-board production of hydrogen as fuel for a 3 kW High-Temperature Proton Exchange Membrane Fuel Cell power system. The analysis uses a three reactions kinetics model for methanol steam reforming, water gas shift and methanol decomposition reactions on Cu/ZnO/Al2O3 catalyst. Numerical simulations are performed at single channel level for a range of reformer operating temperatures and values of the molar flow rate of methanol per weight of catalyst at the reformer inlet. Two operating regimes of …

Optimization Design For A New Type Throttle Valve Of Managed Pressure Drilling Based On Response Surface Methodology, Guorong Wang, Chu Fei, Hongkang Fan, Siyu Tao, Zhu Hao, Jiang Long

Journal of System Simulation

Abstract: The Kriging response surface of single parameter and double parameters versus mass loss of valve spool about bonnet length, bonnet external radius and chamber inner radius of a new type throttle valve used in Managed Pressure Drilling was carried out by using CFX and ANSYS-Design Exploration. The results show that these dimensions have significant influence on erosion mass loss of valve spool. In order to improve the anti-erosion ability of the spool and enhance the service life of the whole valve, the multi-objective genetic algorithm was used for dimensional optimization design of the mentioned variables. After optimization …

Survey Of Airflow Around A Heated Manikin As A Simulated Aeromedical Evacuation Patient On A Litter With Computational Fluid Dynamics Models, George P. Lemmer

Theses and Dissertations

Aeromedical Evacuations remain the predominant method used to transport patients from forward deployed areas of operations to secure locations with more robust medical infrastructure. Transportation of chemical warfare casualties and infectious patients require additional attention to prevent cross contamination. Specific airflow characteristics paired with environmental control system settings are a gap in scholarly literature. Based on the available literature computational fluid dynamics models were created to simulate the airflow around a patient represented by human geometry using commercially available software. In order to compare simulated and experimental results a heated manikin was placed in the MURPHEE aerosol exposure chamber and …

Minimum Induced Drag For Tapered Wings Including Structural Constraints, Jeffrey D. Taylor, Douglas F. Hunsaker

Mechanical and Aerospace Engineering Student Publications and Presentations

LIFTING-LINE theory [1,2] is the foundation for much of our understanding of finite-wing aerodynamics. Solutions based on lifting-line theory are widely accepted and have been shown to be in good agreement with CFD [3-10]. From Prandtl’s analytic solution to the classical lifting-line equation [1,2], the wing section-lift distribution can be expressed as a Fourier series of the form [11]

bL^~ (θ)/L = (4/π)[sin(θ) + Σ^∞_n-2 B_nsin(nθ)]; θ = cos^-1(-2z/b) (1)

where b is the wingspan, L^~ is the local wing section lift, L is the total wing lift, z is the spanwise …

Identification Of Aerodynamic Damping For Flexible Structures Using Wind-Induced Response, Shea Laventure

Electronic Thesis and Dissertation Repository

Damping estimation is a critical task to perform during the design of slender structures, or for existing structures. This is to ensure the response of the structure is within allowable limits and to determine if additional damping is necessary from auxiliary devices. If a slender structure is experiencing wind loading, a phenomenon known as aerodynamic damping arises, which has the potential to reduce the damping of the structure. The most efficient method to estimate aerodynamic damping is to use a system identification technique, which requires only the input forces and output response of the structure. This thesis describes how to …

Simulation Analysis Of Combustion Optimization Scheme For Ultra Supercritical Wall Arrangement Tangential Circle Boiler, Yingbao Li, Dongfeng Wang

Journal of System Simulation

Abstract: To research the combustion optimization scheme of air distribution type selection and low nitrogen oxides (NOx) emission in a 600MW supercritical wall arrangement tangential circle boiler, a modeling and simulating method which applied computational fluid dynamics (CFD) was proposed, the 3D grid model of the boiler is drawn by CAD software, the turbulence model, the radiation model and the inlet boundary condition of the boiler were determined, the boiler combustion simulation experiment was completed. The simulation results show that compared the change of velocity field, temperature field and NOx generation in the furnace under four type air distribution conditions …

Helios And Tenasi Results For The Workshop For Integrated Propeller Prediction, Aaron Crawford

Honors Theses

Beginning in 2018, the AIAA began the workshop for integrated propeller prediction. This effort was intended to bolster the CFD prediction capabilities of the aerospace community due to a resurgent interest in propeller driven vehicles for electric applications. The test bed for this workshop is the NASA X-57, a model of which was experimentally tested in the Lockheed Martin Low Speed Wind Tunnel in January 2019. Using the 3D scanned geometry provided by the workshop a mesh was created and all priority one simulations were performed using two flow solvers. The flow solvers used were Helios, developed by the ADD …

A Numerical Investigation Of Microgravity Evaporation, Daniel Peter Ringle

Dissertations and Theses

Evaporation is important to myriad engineering processes such as cooling, distillation, thin film deposition, and others. In fact, NASA has renewed interest in using cabin air pressure evaporation as a means to recycle waste water in space. As one example, NASA recently conducted experiments aboard the International Space Station (ISS) to measure evaporation rates in microgravity and to determine the impacts of porous structure on the process. It has long been assumed that differences in evaporation rates between 1-g₀ and microgravity are small. However, discrepancies by as much as 40% have been observed in practice. The assumption now …

Numerical Study Of Roundness Effect On Flow Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting

Civil and Environmental Engineering Publications

Imperfectly round bridge stay cable cross section is speculated to be a key factor for wind-induced large-amplitude cable vibrations observed on site. A delayed detached eddy simulation implemented in Open source Field Operation and Manipulation is used to investigate the flow structure around and in the near-wake of an imperfectly round circular cylinder and the corresponding aerodynamic forces at a Reynolds number of 104 and an attack angle of 0° or 45°. With the increase in roundness imperfection, both monotonic and non-monotonic changes of the mean surface pressure and the wake velocity are found when the cylinder is normal to …

A Protocol For Automated A Posteriori Adaptive Meshing With Simvascular: A Test Case, Akash Gupta, Ethan Kung

Publications

Objective

Operational details regarding the use of the adaptive meshing (AM) algorithm available in the SimVascular package are scarce despite its application in several studies. Lacking these details, novice users of the AM algorithm may experience undesirable outcomes post-adaptation such as increases in mesh error metrics, unpredictable increases in mesh size, and losses in geometric fidelity. Here we present a test case using our proposed iterative protocol that will help prevent these undesirable outcomes and enhance the utility of the AM algorithm. We present three trials (conservative, moderate, and aggressive settings) applied to a scenario modelling a Fontan junction with …

Rough Airfoil Simulation For Wind Turbine Applications, Nathaniel B. Develder

Doctoral Dissertations

As a result of insects or other environmental fouling, surface roughness on wind turbine blades can reduce power output significantly. Superhydrophobic surfaces, though possibly a passive, cost-saving, answer to the problem of ice accretion on wind turbine rotors in cold climates, may alter turbulence development in the blade boundary layer similar to environmental roughness. This work uses an equivalent sand grain extension to the Turbulent Potential model to computationally assess the aerodynamic effects of surface roughness on the s809 airfoil, including a representational superhydrophobic surface. Rough surface boundary layer theory, application of the equivalent sand grain method, roughness parameter correlation, …

Design And Analysis Of A Disk-Oriented Engine Combustor, Bennett M. Staton

Theses and Dissertations

In a novel approach to gas-turbine power production, an engine was designed and analyzed to use both a single-stage centrifugal compressor and single-stage radial in- ow turbine configured back-to-back. This air path reduced the axial length of the engine up to 60%, providing additional modularity in a gas-turbine engine that could be used to improve mobility of ground-based power units or increase the survivability of aircraft through the use of distributive propulsion. This increased modularity was made possible by the use of a circumferential ow combustor that substantially decreased the axial length of the burner and negated the need to …

Development Of A Computationally Inexpensive Method Of Simulating Primary Droplet Breakup, Brendon A. Cavainolo

Honors Undergraduate Theses

Liquid droplet impingement on aircraft can be problematic as it leads to ice accretion. There have been many incidents of aircraft disasters involving ice accretion, such as American Eagle Flight 4184. Understanding liquid droplet impingement is critical in designing aircraft that can mitigate the damages caused by icing. However, the FAA's regulations are only specified for "Appendix C" droplets; thus, aircraft designs may not be safe when accounting for droplets such as Supercooled Large Droplets. The assumptions of many models, such as the Taylor-Analogy Breakup (TAB) model, are no longer accurate for Supercooled Large Droplets, and the physics of those …

Editorial For The Special Issue On Micro/Nano-Chip Electrokinetics, Volume Iii, Shizhi Qian, Xiangchun Xuan

Mechanical & Aerospace Engineering Faculty Publications

No abstract provided.

Performance Optimisation Of A Sensing Chamber Using Fluid Dynamics Simulationfor Electronic Nose Applications, Punjan Dohare, Sudeshna Bagchi, Amol P. Bhondekar

Turkish Journal of Electrical Engineering and Computer Sciences

The sensor chamber plays a significant role in order to improve the performance of an electronic nose in terms of stability, repeatability, reproducibility, and sensitivity. Fluid dynamics simulations of six different configurations of 3D sensing chambers are presented to facilitate the efficient design of an electronic nose system comprising 64 sensor arrays. Numerical simulations were carried out to investigate the gas (zero air) flow behaviour inside these chambers under steady-state conditions for velocities ranging from 0.1 to 2 m/s using ANSYS software. Design optimisation was performed in terms of area coverage, velocity, and mass fraction. The results show that the …