Mechanical Engineering Commons^™

Scale Model Investigations Of The Effects Of Flow Conditioning Devices, Grady P. Saunders

Masters Theses

A scale model was constructed of a portion of a supersonic wind tunnel to perform experiments on various flow conditioning devices. The various devices researched were: swirl vanes, screens, honeycombs, and various combinations thereof. Each flow conditioning device was analyzed to show its effect on total pressure profiles, static pressure profiles, test section flow angularity, test section turbulence, and acoustic noise. Of most concern are the effects flow conditioning devices have on temporal fluctuation of previously mentioned parameters.

The data from these experiments were used as the basis for selecting a screen-honeycomb combination to be installed in the full-scale tunnel. …

Discrete Event Simulation In Manufacturing Environments: The Waste Isolation Pilot Plant, Benjamin Thomas Burnette

Masters Theses

The purpose of this thesis was to construct a discrete event model of the waste handling activities inside of the Waste Isolation Pilot Plant (WIPP) in order to examine "what-if" scenarios designed to increase the rate at which waste is disposed.

The discrete event modeling software EXTEND was chosen by Sandia National Laboratories (Sandia) because of its ease of use, flexibility, ability to customize, and low cost. Historical and observed data were used to construct, verify, and validate the resulting model. Verification ensures that the model works as programmed, and validation ensures the real world system is truly being modeled …

Heat Release Analysis And Modeling For A Common-Rail Diesel Engine, M. Rajkumar

Masters Theses

The main purpose of this study was to perform a heat release analysis in order to formulate a heat-release model for a common-rail diesel engine. The fundamental idea of the model is to describe the observed physical processes with empirical formulas based on the experimental data.

A Fiat 2.4Liter common rail engine was used in the tests. A rotary incremental encoder with 0.1° resolution was coupled to the crankshaft pulley with a special adapter. The engine was operated at a number of different speeds and load conditions. Cylinder pressure data was recorded using a high-speed data acquisition system. The data …

Determination Of The Performance Of A Prototype Turbx Engine, Kurt Erickson

Masters Theses

The purpose of this study was to develop a testing procedure to measure the performance of a prototype TurbX. engine. Dr. Michael A. Wilson invented a new concept internal combustion engine called TurbX. and it is said to have higher efficiency and fuel economy compared to other engines. Theoretically, the TurbX. engine cycle can be ideally represented by the Atkinson thermodynamic cycle with a continuous combustion process.

Oak Ridge National Laboratory and The University of Tennessee, Knoxville joined together to conduct tests to determine the performance of the TurbX. engine. A total of 26 fired test runs were conducted to …

An Experimental And Numerical Study Of Open Cavity Flows, Sekhar Radhakrishnan

Doctoral Dissertations

This work is part of an ongoing study aimed at understanding of cavity flow oscillations. An experimental setup was designed, constructed, and tested to measure the Sound Pressure Levels (SPL) on the floor of four cavities, and to quantitatively visualize the flow-field inside the cavity. Measurements were made for a fixed cavity width by depth ratio of 3.33, for four length by depth (L/D) ratios of 2.0, 2.5, 3.5 and 4.5. Using Particle Image Velocimetry (PIV), the cavity velocity fields were obtained at subsonic speeds ranging from Mach 0.3 to Mach 0.6. Numerical simulations were performed for cavity geometry configurations …

An Experimental Study Of Low Speed Open Cavity Flows, Abraham J. Meganathan

Masters Theses

The experimental work is part of an ongoing study aimed at understanding and controlling of cavity instabilities by passive or active steady or unsteady fluid injection. An experimental setup has been designed to quantitatively visualize the flow-field inside the cavity for varying relative dimensions (L/D ratios of 2.0, 2.67, 3.5 and 4.5, W/D of 3.33) at low subsonic speeds ranging from 55 ft/sec to 214 ft/sec using Particle Image Velocimetry (PIV).

The results showed that PIV could provide instantaneous velocity and other flow field data inside and above the cavity. The quality of data is good and may be used …

One-Dimensional Mean Line Code Technique To Calculate Stage-By-Stage Compressor Characteristics, Sherri Lynette Smith

Masters Theses

Because modem turbine engines have such complex flow fields, extensive testing is required to ensure stability. The testing of these engines and their components is very expensive. To offset testing costs, computer simulations are often used. Several computer simulations have been developed at Arnold Engineering Development Center for this purpose. These codes require stage-by-stage compressor characteristics in order to simulate flow through a compressor.

A technique to calculate compressor characteristics was developed using a mean line code (MLC). This MLC was modified to include loss and deviation correlations from open literature and to account for the conservation of angular momentum …

The Experimental Analysis Of Aqueous Lithium Bromide Vertical Film Absorption, William A. Miller

Doctoral Dissertations

A heat and mass transfer test stand was fabricated and used to investigate nonisothermal falling film absorption of water vapor into a solution of aqueous lithium bromide. The absorber was made of borosilicate glass for visual inspection of the falling film. Experiments were conducted on an internally cooled smooth tube of about 0.019 m outside diameter and of 1.53 m length. Laboratory testing evaluated the tube's performance at varying falling film flow rates, pressures, temperatures, and concentrations. No heat and mass transfer additive was used during testing nor had it been previously added to the stand.

The coolant temperature profile …

Investigation And Demonstration Of A Rich Combustor Cold Start Device For Alcohol Fueled Engines, David Kim Irick

Doctoral Dissertations

Alcohols (methanol and ethanol) have been identified as having the potential to improve air quality when used to replace conventional gasoline. This potential is primarily due to the different organic species that are emitted by alcohol-fueled engines. The use of "near neat" alcohols gives greater benefits than fuels containing lower levels of alcohol, but neat alcohols present a significant cold starting problem.

The primary objective of this study was to develop a rich combustor device which will extend the cold start range of alcohol fueled engines to -30°C while reducing cold start emissions. In support of this objective a software …

Atec: The Aerodyanmic Turbine Engine Code For The Analysis Of Transient And Dynamic Gas Turbine Engine System Operations, Glenn Douglas Garrard

Doctoral Dissertations

A new one-dimensional, time dependent aerothermodynamic mathematical model and computer simulation of the gas turbine engine has been developed and is introduced herein. The Aerodynamic Turbine Engine Code (ATEC) simulates the operation of the gas turbine engine by solving conservation equations, expressed as one dimensional, time dependent Euler equations, with turbomachinery source terms. By incorporating both implicit and explicit equation solvers, transient simulations of the gas turbine engine can be conducted efficiently while maintaining the capability of simulating dynamic events such as compressor stall. ATEC can also be used to address dynamic events or steady-state processes to model both on- …

Mechanical Impedance Methods For Vibration Simulation, Jeffrey Allen Gatscher

Masters Theses

Realistic laboratory simulation of a system's field vibration environment has been of major concern to design and test engineers for many years. The usual practice of basing vibration design and test specifications on an envelope of the equipment base acceleration levels experienced in the field environment has often resulted in excessive levels of overtesting. This results from the large differences between the mechanical impedance of the vehicle structure and that of a fully equalized vibration shaker. Mechanical impedance effects occur naturally in a field environment. Including such effects in a laboratory vibration environment achieves more realistic conditions of similitude. A …

Design Of Nozzle Contours For The Pwt 16-Ft Transonic Wind Tunnel, William Everett Milam

Masters Theses

The nozzle contours of the Tunnel 16T nozzle were designed in the early 1950's and, for the most part, were calculated by hand. In addition, corrections have been made to the contours through the use of an influence coefficient correction technique in an attempt to remove small flow irregularities. This correction technique is not based on aerodynamic theory, and, as a result the corrected contours are not necessarily aerodynamically correct. A second problem stems from the fact that the application of the nozzle corrections results in nozzle contours that do not change in a monotonic manner. There are some jacks …

An Experimental And Analytical Investigation On The Production Of Microfibers Using A Single Hole Melt Blowing Process, Bryan David Haynes

Doctoral Dissertations

An extensive experimental investigation was undertaken to study the influence of the processing variables on the production of microfibers using a single hole melt blowing process. included: The processing variables that were investigated air jet exit velocity, polymer throughput, die air gap, die setback, polymer and air temperatures, polymer melt viscosity as expressed by ASTM Melt Flow Rate (MFR), and collection distance. Polypropylene was used for the investigation. In addition to the experimental investigation, a one dimensional single hole melt blowing analytical model was developed.

The air jet exit velocity and polymer throughput had the most influence on the average …

An Investigation Of The Combined Heat And Mass Transfer Processes In The Drying Of Hygroscopic Porous Media With Two Disparate Length Scales, Thomas Joseph Phillips

Doctoral Dissertations

A mathematical model describing the drying process in a hygroscopic porous medium with two disparate length scales is formulated. The mathematical model is used to identify the important dimensionless parameters appearing in the problem; and, a parametric study is performed to determine the effects of varying these parameters on the drying process. Of particular interest in this study is to apply the model to the drying of large, round hay bales. Therefore a discussion of how the results of the parametric study impact on the efficient use of a hay drier is also presented.

The results from the parametric study …

Transient Response Of A Packed Bed For Both Sensible And Latent Thermal Energy Storage, Shi-Hong Ji

Doctoral Dissertations

The present work was undertaken to provide a model which accurately predicts the performance of a packed bed energy storage system utilizing spherically encapsulated phase-change material (PCM). Two models were developed which are referred to as the first-order and second-order models. Both models involve modeling of the phase-change material as a conduction problem with both sensible and latent energy storage and include consideration of the temperature gradients in both phases. Both models include the solution of the energy equation for the fluid passing through the packed bed. In the second-order model, both the intra-particle conduction and the dispersion effects in …

Modeling Of A Combined Cycle Mhd/Steam Power Plant, Edward H. Kiessling Iii

Masters Theses

The objective of this effort was to develop an improved process model of a prototype MHD/steam central station power plant. This model was designed to perform a first law thermodynamic analysis for steady state plant operation. An existing MHD topping cycle model was modified to provide predictions of mass flows and energy requirements associated with topping cycle equipment for coal processing and oxidant preparation. This topping cycle is characterized by full slag carryover to the heat and seed recovery system. PRESTO II, a program for analyzing the performance of regenerative, superheated steam-turbine cycles, was added to the existing model structure …

A Wear Minimization Design Investigation Of Feedline Splitters, Turning Sections, And Feed Nozzles Of A Pneumatic Conveyed Solids System, Warren R. Gilbert Jr.

Masters Theses

The adverse effects of wear has continually plagued the operation of the TVA 20 MW Atmospheric Fluidized Bed Combustion Pilot Plant. Wear has caused serious problems in all aspects of the pneumatically fed below-bed coal feed system. This has given rise to the development of high wear resistant designs of feedline splitters, turning sections, and feed nozzles.

Wear testing of PVC feedline system components was conducted at The University of Tennessee to determine the wear characteristics of different designs. PVC was chosen for the feedline system component material to accelerate the wear testing results. A series of similar tests were …

Performance Of A Ground-Coupled Heat Pump During A Cooling Season, Steven D. Wix

Masters Theses

A ground-coupled heat pump system was installed in TECH House I at the Tennessee Energy Conservation in Housing site located on the University of Tennessee campus. The performance of the heat pump system was evaluated for the cooling season of 1983. Data on system energy flows, power consumption, house temperatures, soil temperatures and weather conditions were gathered on an hourly basis for the entire cooling season. Weekly coefficients of performance, soil thermal conductivitys, and a seasonal performance factor were calculated from experimental data.

The performance was found to be poor when compared to a conventional air-to-air heat pump system. The …

A General Solution For Wind Tunnel Boundary-Induced Interference In Two-Dimensional Subsonic Flow, Werner Johann Anton Dahm

Masters Theses

A general solution is presented for determination of wind tunnel boundary-induced interference in two-dimensional subsonic flow. The solution requires no a priori knowledge of the model geometry or tunnel wall characteristics, and instead, relates the interference to velocity measurements at a selected control surface within the tunnel. The solutions for the tunnel, free-air and interference fields are obtained using linearized subsonic theory with the Fourier transform technique. An analytical example dealing with the case of the wavy wall in the presence of a generalized tunnel wall boundary condition demonstrates the validity of the solutions in closed form. Numerical examples dealing …

Energy And Cost Analysis Of Commercial Hvac Equipment: Offices And Hospitals, Robert E. Lyman Jr.

Masters Theses

A study was made to determine annual energy use in several typical heating, ventilating, and air conditioning (HVAC) systems for two commercial building types: offices and hospitals. The study was part of a program at Oak Ridge National Laboratory to develop a model to predict energy use in the commercial sector of the United States. This study's objective is to define relationships between energy use and capital cost for commercial HVAC systems.

The NECAP computer program was used to analyze the HVAC systems' energy use. Both pre-embargo and current energy efficient HVAC system designs were modeled with several energy conservation …

Energy Conservation And Economic Analysis Of Residential Refrigerators, Robert A. Hoskins

Masters Theses

A detailed computer model is developed to calculate energy flows and electricity use for residential refrigerators. Model equations are derived from application of the first law of thermodynamics, analysis of manufacturers' literature, and related studies. The model is used to evaluate the energy (and associated initial cost) impacts of alternative designs to reduce refrigerator energy use.

Model results show that 56% of the total heat gain in a typical 0.45 m³ (16 ft³) top-freezer refrigerator is due to conduction through cabinet walls and doors. The remaining 44% is from door openings, heaters, fans, food, gasket area infiltration, …

Transient Response Of Linear Elastic Structures Determined By The Matrix Exponential Method, William Christopher Terrill Stoddart

Masters Theses

This investigation was undertaken to develop a numerical solution for the transient response of linear, elastic structures based on the matrix exponential solution for first order, linear, constant coefficient differential equations. The investigation was prompted by the need for an economical technique that can be used to analyze multidegree of freedom systems exemplified by piping and structural components associated with nuclear power plants.

A mathematical model characterizing the behavior of linear, elastic structures was developed by using state variables of displacement and velocity. The structure consists of beam elements of uniformly distributed mass, weightless springs, and rigid masses. The stiffness …

An Experimental Study Of The Viscoseal Bearing, Chandrakant Khumaji Shah

Masters Theses

The experimental data obtained from two groove geometries of the viscoseal bearing were analyzed to study the bearing characteristics and the sealing performance. The experimental bearing characteristics were compared with the Dubois and Ocvirk Short-bearing Approximation. The sealing performance analysis of the bearing included (1) the determination of the sealing coefficient which was compared with the Stair and Hale method of theoretical prediction and (2) the effect of the bearing eccentricity ratio on the sealing coefficient, which was compared with the Vohr and Chow method of theoretical prediction.

The results of the study indicated that, at constant load and speed, …

An Analytic Study Of Microlayer Evaporation And Related Bubble Growth Effects In Nucleate Boiling, Gerald Steven Dzakowic

Doctoral Dissertations

Introduction: Nucleate boiling heat transfer is of technical interest since it allows a high heat flux with only a relatively small temperature difference. The demand for a better understanding of the behavior of a liquid as it exceeds its saturation temperature and changes to vapor has been the result of design problems in liquid cooled rocket nozzles and nuclear reactor cores. Moreover, to improve the performance of these high heat flux systems an understanding and control of the phenomena of boiling must be achieved. This dissertation is an attempt to establish the criteria for the heat and mass transfer processes …

The Design And Construction Of A Visco Seal Test Facility, Charles Franklin Bowman

Masters Theses

No abstract provided.

The Analysis Of Cantilever Plates With Concentrated Loads, Constant Roberts Marks

Masters Theses

(From the Introduction)

The problem of a cantilever plate or slab with variable, discontinuous, concentrated, or eccentric loading occurs frequently in engineering design. Examples are substructure walls, piers, projecting floor slabs, and gear teeth. The solution of most of these problems can be made to depend on the analysis of the plate in question loaded with one or more concentrated loads. Such analyses are available for only a few cases of loading, and no practical method is available to the designer for making any kind of a reasonably accurate stress analysis for many cases he may encounter.

In …