Mechanical Engineering Commons^™

Validation Of A Modified Parallel Compressor Model For Prediction Of The Effects Of Inlet Swirl On Compressor Performance And Operability, Reggie Floyd

Masters Theses

Engine inlet distortion complications have plagued the turbine engine development community for decades, and engineers have developed countless methods to identify and combat the harmful effects of inlet distortion. One such type of distortion that has gained much attention in recent years is known as inlet swirl, which results in a significant flow angularity at the face of the engine. This flow angularity can affect the pressure rise and flow capacity of the fan or compressor, and subsequently affect compressor and engine performance.

Previous modeling and simulation efforts to predict the effect inlet swirl can have on fan and compressor …

Design And Model Of The Frame For Hagrid (Hybrid Array Of Gamma Ray Detectors), Santiago Munoz

Masters Theses

Transfer reactions in inverse kinematics have provided critical information in the study of exotic nuclei. However, transfer reactions with charged particles suffer from poor resolution. The measurement of gamma-rays offers several advantages: they provide not only good resolution in measurements but also other information about the nuclei like lifetimes of unstable states. The combination of these two methods would be the ideal situation to gather information about nuclear structure.

HAGRiD, which stands for The Hybrid Array of Gamma Ray Detectors, is a LaBr3(Ce) [lanthanum bromide crystal with a cerium activator] scintillation array to measure gamma rays from transfer reactions and …

Design And Fabrication Of A Low-Cost Turbine Engine Component Testbed (Tect), Joshua A. Hartman

Masters Theses

With gas turbine engine testing becoming very expensive because of the increasing complexity involved with the engine, engine subsystems, and test support systems, a low-cost Turbine Engine Component Testbed (TECT) is proposed. This engine build is given the designation J1-H-02. In the present study, a small augmented gas turbine engine (GTE) is constructed. The TECT engine is built with modularity as a key design consideration to allow for flame-tube patterns and augmentor sections to be changed quickly for combustion experiments that have gained impetus due to combustion anomalies/instabilities inherent with future military engine augmentors. This testbed allows for an effective …

Simulating High Flux Isotope Reactor Core Thermal-Hydraulics Via Interdimensional Model Coupling, Adam Ross Travis

Masters Theses

A coupled interdimensional model is presented for the simulation of the thermal-hydraulic characteristics of the High Flux Isotope Reactor core at Oak Ridge National Laboratory. The model consists of two domains—a solid involute fuel plate and the surrounding liquid coolant channel. The fuel plate is modeled explicitly in three-dimensions. The coolant channel is approximated as a two-dimensional slice oriented perpendicular to the fuel plate’s surface. The two dimensionally-inconsistent domains are linked to one another via interdimensional model coupling mechanisms. The coupled model is presented as a simplified alternative to a fully explicit, fully three-dimensional model. Involute geometries were constructed in …

Rotordynamic Analysis Of A Two-Pole Synchronous Motor With Sleeve And Pressure Dam Bearings, Justin Matthew Garrard

Masters Theses

A two-pole synchronous motor was recently rewound for the von Karman Gas Dynamics facility at Arnold Engineering Development Complex, Arnold Air Force Base, Tennessee. After installing the rewound rotor, unexpected vibration amplitudes were recorded during motor checkouts. To resolve this issue, an investigation was initiated to investigate the causes of the vibration issues. The investigation discovered that the original design used sleeve bearings rather than pressure dam bearings. A study was formed to determine the effect of changing the pressure dam bearings back to sleeve bearings. Because only one spare bearing shell existed, the bearing with the highest vibration amplitudes …

Thermal Response Characterization And Low Fluid Velocity Measurements Using Specialized In-Situ Thermocouples Via The Loop Current Step Response Method, Alexander Hashem Hashemian

Masters Theses

In this study, a specialized balanced-leads thermocouple was developed to perform in-situ thermal response characterization via the LCSR test method. Thermal response characterization of installed thermocouples is essential in order to obtain accurate positional temperature data in rapid transient applications. An analytical model is presented that fully describes the thermocouple system based on a first-principles approach to the heat transfer physics of the sensor. In conjunction with the LCSR test, the full model presented yields quantifiable characterization parameters useful for determining accurate positional temperature data. It is necessary to employ a balanced-leads thermocouple for this experimental procedure in order to …

Neutron Imaging Of Lithium (Li) Coolants Inside High Temperature Niobium (Nb) Heat Pipes, Brad Harrison Hight

Masters Theses

Lithium (Li) behavior inside a high temperature Nb-Li leading edge heat pipe was successfully imaged under induction heating operation via neutron imaging. Startup and cool-down operations gave visual confirmation of bulk Li movement using both gravity assisted and inverted operating orientations. The pipe was imaged during an operation cycle from ambient conditions, heated to a steady state temperature of 908.8 ⁰C, and allowed to cool below 200^°C. The experiment was performed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, and at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee.

Tomographic images …

Formulation And Experimental Verification Of Alternate Calibration Techniques Of The Temperature Dependent Response Of Phosphor Fluorescence, Kelsey Michele Winstead

Masters Theses

The overall goal of this work is to provide an alternative approach to the thermographic phosphor (TP) time constant calibration method for temperature recovery. In this work two techniques are proposed that retain the pulsed source input used in the standard TP time constant calibration approach but reinterpret the phosphor response taken a fixed distance such that the single-exponential decay assumption is removed. The methods do not require knowledge of key parameters prior to data processing, nor do they involve complicated numerical schemes that attempt to fit data in the low signal-to-noise region of the phosphor response. The approaches do …