Engineering Commons^™

Aeroelastic Analysis Of A Wind Turbine Blade Using The Harmonic Balance Method, Jason Charles Howison

Doctoral Dissertations

Most current wind turbine aeroelastic codes rely on the blade element momentum method with empirical corrections to compute aerodynamic forces on the wind turbine blades. While efficient, this method relies on experimental data and does not allow designers much flexibility for alternative blade designs. Unsteady solutions to the Navier-Stokes equations offer a significant improvement in aerodynamic modeling, but these are currently too computationally expensive to be useful in a design situation. However, steady-state solutions to the Navier-Stokes equations are possible with reasonable computation times. The harmonic balance method provides a way to represent unsteady, periodic flows through coupled a set …

Characterization Of Convective Heat Transfer Coefficients Of A Self-Aspirated Hot Gas Temperature Probe, Samuel David Stephens

Masters Theses

The objective of this work is to provide a Nusselt Number in a Reynolds Number and Prandtl Number correlation for various surfaces of an aspirated total temperature probe exposed to high temperature flow. The experiment discharged thermally stabilized dry air through large scale models of the probe surfaces in a blow-down wind tunnel and a direct connect facility. The model contained electrically heated sections exposed to the flow which were thermally insulated and instrumented with thermocouples. Experimental data were recorded for several Reynolds numbers and heater positions across three configurations. Uncertainty analysis was performed by the Monte Carlo uncertainty propagation …

Optimization Of Titanium Liquid/Gas Diffusion Layers In Proton Exchange Membrane Electrolyzer Cells, Stuart Mccoy Steen

Masters Theses

Polymer electrolyte membrane electrolyzer cells (PEMECs), which are reverse PEM fuel cells (PEMFCs), are effective energy storage medium by producing hydrogen/oxygen from water using electricity from renewable energy sources. This is due in part because of its efficiency, high energy density, compact design, and large capacity. In a PEMEC, a liquid/gas diffusion layer (LGDL) is located between the catalyst layer and the current distributing flow field. The LGDL is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. Carbon materials (carbon paper or carbon cloth), typically used …

Measurements Of Methyl Radicals And Temperatures By Using Coherent Microwave Rayleigh Scattering From Resonance Enhanced Multiphoton Ionization, Yue Wu

Doctoral Dissertations

This thesis includes two main parts: (I) The CH₃[methyl radical] detection in methane/air flames and (II) the rotational temperature measurement of O₂[molecular oxygen] in a variety of environments by using coherent microwave Rayleigh scattering from resonance enhanced multiphoton ionization (Radar REMPI).

In first the part, from Chapter I to Chapter III, the methyl radical detection and quantitative measurements have been conducted in hydrocarbon flame with one-dimensional and two-dimensional spatial-resolved concentration distribution. Due to the proximity of the argon resonance state (4+1 REMPI by 332.5 nm) with the CH₃ state (2+1 REMPI by 333.6 nm), in …

Flight Testing The Piper Pa-32 Saratoga And Pa-31 Navajo, Matthew John Dimaiolo

Masters Theses

The purpose of this thesis was to flight test the University of Tennessee Space Institute’s PA-32 Saratoga and PA-31 Navajo and provide baseline data for future students to reference. Flight tests consisted of both performance and stability and control parameters using a variety of flight test techniques. The tests selected represent the fundamentals that are taught in classes and short courses at the university, beginning with the air data system calibration, proceeding to cruise and climb performance, to stall performance and characteristics, and to static and dynamic stability.

After an introduction and description of the aircraft and flight test program, …

Trajectory Analysis And Comparison Of A Linear Aerospike Nozzle To A Conventional Bell Nozzle For Ssto Flight, Elizabeth Lara Lash

Masters Theses

Single-stage to orbit (SSTO) rocket technology offers the potential to substantially reduce launch costs, but has yet to be considered practical for conventional launch vehicles. However, new research in composite propellant tank technology opens the field for renewed evaluation. One technology that increases the efficiency and feasibility of SSTO flight is an altitude compensating rocket engine nozzle, as opposed to a conventional constant area, bell nozzle design. By implementing an altitude compensation nozzle, such as a linear, aerospike nozzle for in-atmosphere flight, the propellant mass fraction (PMF) may be reduced by as much as seven percent compared to a conventional …

Analysis Of Flammability Limits And Gas Properties Of A Solid Rocket Motor Test In A High Altitude Test Facility, Richard Scott Kirkpatrick

Masters Theses

The testing of solid and liquid rocket propulsion systems in a confined test facility often produces explosive or flammable gases which must be safely handled. Often inert gases such as nitrogen are used to lower the molar fraction of oxygen to low enough levels to minimize the probability of an explosion or deflagration. For this thesis, the chemical composition of these rocket exhaust gases mixed with air were used to determine the flammability limits of the gas mixture. Using the ideal gas law and the conservation of mass, the exhaust gas composition and gas properties such as pressure, temperature, volume …

Cfd Analysis Of Viscosity Effects On Turbine Flow Meter Performance And Calibration, Carl Tegtmeier

Masters Theses

In this research turbine flow meters were studied, using computational fluid dynamics (CFD) modeling to the study effects of viscosity on the flow meters, across a wide range of operation, to improve our understanding and their performance. A three-dimensional computational model was created for a typical flow meter geometry. The work began with a steady state model to provide an acceptable initial condition for further simulations. These results were input into a transient model that has a rotating zone around the rotor to provide insight into the interaction between static and rotational structures. In order to automatically adjust the rotor …

Design, Testing, And Calibration Of A Custom Air Data Boom To Obtain Flight Data For The Utsi Cessna-T210j (N33ut), Kristopher Nathaniel Oegema

Masters Theses

Flight testing is dependent on the ability to accurately calculate the flight characteristics of an aircraft during a test. Any error caused by an instrument will grow into potentially larger errors or unacceptable ranges of uncertainty for any flight test calculations. The aircrafts pitot static system is designed to minimize the error in readings caused by the pressure changes resulting in air flying around the aircrafts structure. However, it still does not meet the level of accuracy desired for quality flight testing data. In order to get the most accurate data possible noncommercial equipment is installed on the aircraft for …