| Unsteady Specific Work and Isentropic Efficiency of a Radial Turbine Driven by Pulsed Detonations |
14 Jun 2012 |
263 pages |
| Authors:
Kurt P Rouser; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
 | There has been longstanding government and industry interest in pressure-gain combustion for use in Brayton cycle based engines. Theoretically, pressure-gain combustion allows heat addition with reduced entropy loss. The pulsed detonation combustor (PDC) is a device that can provide such pressure-gain combustion and possibly replace typical steady deflagration combustors. The PDC is inherently unsteady, however, and comparisons with conventional steady deflagration combustors must be based upon time-integrated performance variables. In ... |
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| Endwall Loss and Mixing Analysis of a High Lift Low Pressure Turbine Cascade (Preprint) |
May 2012 |
14 pages |
| Authors:
M E Lyall; Paul I King; Rolf Sondergaard; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| A high lift LPT profile designated L2A is used as a test bed for studying the origin of endwall mixing loss and the role of vortical structures in loss development. It is shown analytically and experimentally that the mixing forces within the endwall wake can be decoupled into either mean flow or turbulent forces, and can be further classified as either reversible or irreversible. Among the irreversible forces, mean flow ... |
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| Influence of Alternative Engine Concepts on LCTR2 Sizing and Mission Profile |
Jan 2012 |
16 pages |
| Authors:
Jr Acree C W; Christopher A Snyder; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER
|
| The Large Civil Tiltrotor (LCTR) was developed as part of the NASA Heavy Lift Rotorcraft Systems Investigation in order to establish a consistent basis for evaluating the benefits of advanced technology for large tiltrotors. The concept has since evolved into the second-generation LCTR2, designed to carry 90 passengers for 1,000 nm at 300 knots, with vertical takeoff and landing. This paper examines the impact of advanced propulsion system concepts on ... |
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| Maximum Power Point Tracking Control of Hydrokinetic Turbine and Low-speed High-Thrust Permanent Magnet Generator Design |
Jan 2012 |
97 pages |
| Authors:
Hailong Zhou; MISSOURI UNIV OF SCIENCE AND TECHNOLOGY ROLLA
|
| River-based hydrokinetic turbine power generation systems have been studied to introduce an effective energy flow control method. Hydrokinetic turbine systems share a lot of similarities with wind turbine systems in terms of physical principles of operation,electrical hardware, and variable speed capability for optimal energy extraction. A multipole permanent magnet synchronous generator is used to generate electric power because of its ability to reach high power density and high thrust at ... |
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| The Hierarchy of Fatigue Mechanisms in the Long Lifetime Regime (Preprint) |
Oct 2011 |
8 pages |
| Authors:
C J Szczepanski; C P Przybyla; J M Larsen; S K Jha; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIR METALS CERAMICS AND NONDESTRUCTIVE EVALUATION DIV/METALS BRANCH
|
| The primary factors governing the behavior in the long lifetime regime of turbine engine materials are discussed. These factors are based on a study of fatigue lifetime distributions and underlying mechanisms in a number of materials, including titanium alloys, nickel-base superalloys, and gamma TiAl based alloys. A hypothesis of fatigue variability is described, and appears to explain the various features of fatigue behavior seen in the HCF and VHCF regimes. ... |
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| American Recovery and Reinvestment Act Wind Turbine Projects at Long-Range Radar Sites in Alaska Were Not Adequately Planned |
30 Sep 2011 |
30 pages |
| Authors:
INSPECTOR GENERAL DEPT OF DEFENSE ARLINGTON VA
|
| Our overall objective was to evaluate DoD s implementation of Public Law 111-5, American Recovery and Reinvestment Act of 2009, (Recovery Act), February 17, 2009. Specifically, we reviewed the planning, funding, initial project execution, and tracking and reporting of the wind turbine projects, each valued at $4.7 million, located at long-range radar site(s) (LRRS) at Cape Lisburne, Cape Newenham, and Cape Romanzof, Alaska. We determined whether Air Force personnel complied ... |
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| Adaptive Control and Parameter Identification of a Doubly-Fed Induction Generator for Wind Power |
Sep 2011 |
103 pages |
| Authors:
Stamatios Orfanos-Pepainas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The use of Doubly-Fed Induction Generators (DFIG) for wind energy conversion is addressed in this thesis. It is well known that when the stator is connected to the electric grid, the rotor voltage can control both mechanical torque and reactive electric power. To guarantee efficient wind energy conversion, it is important to research and design more advanced control schemes. In this thesis, we first review the basic theory behind DFIGs ... |
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| Cavitation-Resistant Coatings for Hydropower Turbines |
JUN 2011 |
67 pages |
| Authors:
Ryan Sollars; Alfred D. Beitelman; ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
|
| Operating hydropower turbines to obtain the ultimate power output often results in cavitation (the rapid formation and collapse of vapor pockets in a flowing liquid in regions of very low pressure) in the turbine area. The level of cavitation typically destroys organic coatings in a relatively short time. Traditional metallizing to repair cavitation damage has resulted in unsatisfactory performance. Other coating systems, such as those deposited by High Velocity Oxygen ... |
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| Department of Defense Landfill Database: A Collection of DoD-Wide Landfill Data for the Assessment of Implementing the Flex Energy Powerstation for Landfill Gas to Energy Projects |
Jun 2011 |
28 pages |
| Authors:
Tim Hansen; SOUTHERN RESEARCH INST BIRMINGHAM AL
|
| The objective of this task was to collect data on all landfills owned by the Department of Defense and to use that information to calculate gas production rates in order to determine which sites may be appropriate for the Flex Microturbine. Given the approximate nature of the source data and the gas production models, this material can only be used for a preliminary assessment, based on which more detailed site-specific ... |
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| American Recovery and Reinvestment Act Projects - Facility Energy Improvements and Wind Turbine and Photovoltaic Panels at Fort Wainwright, Alaska |
07 MAR 2011 |
23 pages |
| Authors:
INSPECTOR GENERAL DEPT OF DEFENSE ARLINGTON VA
|
| Our overall objective was to evaluate DoD's implementation of the "American Recovery and Reinvestment Act of 2009," February 17, 2009 (Recovery Act). Specifically, we reviewed the planning, funding, initial project execution, and tracking and reporting phases of the two Energy Conservation Investment Program (ECIP) projects, "Facility Energy Improvements" and "Wind Turbine and Photovoltaic Panels" at Fort Wainwright, Fairbanks, Alaska. We determined whether Army personnel complied with the Recovery Act requirements, ... |
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| Measurement of the Effectiveness of Concave Spherical Dimples for the Enhancement of Hot-gas Side Heat Transfer |
31 JAN 2011 |
13 pages |
| Authors:
Edward B. Coy; Stephen A. Danczyk; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| In an expander cycle rocket engine, the turbo-pump is driven by a gaseous propellant that has been heated in channels incorporated into the thrust chamber wall. The power output of the turbine islimited by the hot gas wall heat transfer coefficient and surface area. To increase the chamber pressure, additional pump power and heat are required. Part of the increase can come from an increased heat transfer coefficient at elevated ... |
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| Offshore Renewable Energy Installations: Impact on Navigation and Marine Safety |
Jan 2011 |
4 pages |
| Authors:
Jr Detweiler George H; COAST GUARD WASHINGTON DC MARINE TRANSPORTATION SYSTEMS MANAGEMENT DIRECTORATE
|
| To reduce our dependence on foreign energy supplies, alternative or renewable energy sources are being pursued. These sources exploit a wide range of technologies: solar photovoltaics or power plants; hydroelectricity (dams); ocean thermal energy conversion facilities; and offshore renewable energy installations, which may include wind farms, marine current turbines, and wave generators (hydrokinetics). All these technologies have the potential to affect marine navigation and safety, and although no offshore renewable ... |
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| The Evaluation of HOMER as a Marine Corps Expeditionary Energy Pre-deployment Tool |
21 NOV 2010 |
149 pages |
| Authors:
Brandon H. Newell; NAVAL POSTGRADUATE SCHOOL MONTEREY CA GRADUATE SCHOOL OF BUSINESS AND PUBLIC POLICY
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| In this thesis, the author evaluates whether HOMER Micropower Optimization should be used by the Marine Corps as a pre-deployment tool for meeting expeditionary energy demands. The author created two unique experiments to facilitate the evaluation of HOMER's modeling capability. First, a grid-tied-photovoltaic (PV) system at the Naval Postgraduate School was monitored for a one-month period. During this experiment, a HOMER model of the system was created. The actual energy ... |
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| Design, Build and Test of an Axial Flow Hydrokinetic Turbine with Fatigue Analysis |
JUN 2010 |
95 pages |
| Authors:
Jerod W. Ketcham; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| OpenProp is an open source propeller and turbine design and analysis code that has been in development since 2007 by MIT graduate students under the supervision of Professor Richard Kimball. In order to test the performance predictions of OpenProp for axial flow hydrokinetic turbines, a test fixture was designed and constructed, and a model scale turbine was tested. Tests were conducted in the MIT water tunnel for tip speed ratios ... |
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| Vision & Needs for Distributed Controls: Customers for Control Systems and What Do They Value (Postprint) |
Aug-2009 |
16 pages |
| Authors:
Alireza Behbahani; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH FAN AND COMPRESSOR BRANCH
|
| Distributed Engine Control Working Group: Coordinate, collaborate, and leverage integrated intelligent distributed (partially) engine controls and PHM technology development to address future and current requirements of both military and civil aviation. Provide an open forum for discussion and proliferation of primary S&T drivers and issues that are being, or should be, addressed. Identify possible transition paths for S&T products. |
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| AMC's Hydrogen Future: Sustainable Air Mobility |
Jun-2009 |
116 pages |
| Authors:
Adam D Reiman; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The purpose of this research is to compare the costs associated with the transition to hydrogen aircraft for Air Mobility Command (AMC) to the costs of continuing using JP-8. Using current technology, air mobility aircraft can be designed to use liquid hydrogen instead of JP-8. This transformation will be capital intensive. A model was built that converted current AMC JP-8 usage to liquid hydrogen usage and calculated the costs of ... |
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| A Low-wear Planar-contact Silicon Raceway for Microball Bearing Applications |
Apr-2009 |
34 pages |
| Authors:
C M Waits; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| As silicon rotary micro-electromechanical systems (MEMS) devices become critical components to power generation and sensor platforms, it is crucial to develop bearing mechanisms that can achieve speed and reliability requirements without increasing cost and complexity. Microball bearings have proven simple to fabricate and capable of achieving high speeds. However, previous microball raceway implementations showed substantial degradation in performance and required cleaning steps to improve reliability. Furthermore, large surface roughness on ... |
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| Cost Analysis of Electric Grid Enhancement Utilizing Distributed Generation in Post-War Reconstruction |
Mar-2009 |
83 pages |
| Authors:
Darol D Fiala; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The current wars in Iraq and Afghanistan have presented significant civil infrastructure rebuilding challenges to these nations, as well as to the United States, coalition allies, and the United Nations. Iraqi and Afghan critical infrastructure has been destroyed, or fallen into disrepair, due to years of war, international sanctions, sabotage and neglect. Electrical infrastructure, in particular, is a critical economic and social component that is failing to meet the essential ... |
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| United States Government Support of Pickens' Energy Plan |
18-Feb-2009 |
34 pages |
| Authors:
Matthew N Smith; ARMY WAR COLL CARLISLE BARRACKS PA
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| Billionaire T. Boone Pickens began a media campaign in July, 2008 to convince the American public and U.S. Congress that the nation should embark on a plan to displace one-third of its oil imports with wind energy within ten years. The plan calls for wind turbines to generate 20 percent of the nation's electricity. This new wind energy will free natural gas, currently used in electricity generation, to replace 47 ... |
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| Propulsion and Power Rapid Response Research and Development Support: Fundamental Science Investigations for Propulsion and Power Systems |
Jan-2009 |
236 pages |
| Authors:
Donald B Hanson; UNIVERSAL TECHNOLOGY CORP DAYTON OH
|
| Research was conducted for the Propulsion Directorate's research and development efforts in core technology areas for turbine engines, hypersonics, and aerospace power. Experimental and theoretical research was conducted in the technical disciplines of fuels and combustion; mechanical subsystems and life management; aerodynamics; aerospace power systems including applied and high temperature superconductivity, physics of electrical discharges, applied atomic and molecular spectroscopy, thermophysics and high temperature dielectric materials, thermal nanofluids for heat ... |
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| Hardware-In-The-Loop Power Extraction Using Different Real-Time Platforms (Postprint) |
Nov-2008 |
9 pages |
| Authors:
Mitch Wolff; Michael Corbett; Michael Boyd; John McNichols; Peter Lamm; PC KRAUSE AND ASSOCIATES INC LAFAYETTE IN
|
| Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion systems and can no longer be neglected or assumed linear in system analyses. The complex models designed to integrate new capabilities have a high computational cost. Hardware-in-the-loop (HIL) is being used to investigate aircraft power systems by using a combination of hardware and simulations. This paper considers ... |
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| Variability in Room Temperature Fatigue Life of Alpha+Beta Processed Ti-6Al-4V (Preprint) |
Oct-2008 |
17 pages |
| Authors:
Reji John; JOHN PORTER; Patrick J Golden; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| In this program, smooth bar fatigue tests were conducted by several laboratories on the same lot of Ti-6Al-4V forged plate material. Multiple stress ratios and stress levels were tested to generate a fully populated stress-life curve. The tests, however, did not typically consist of many repeats. The approach of this work is to conduct a statistically significant number of repeated fatigue tests at a few loading conditions. A similar approach ... |
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| Extractive Sampling and Optical Remote Sensing of F-100 Aircraft Engine Emissions (PREPRINT) |
Oct-2008 |
|
| Authors:
Ram Hashmonay; Jan Satola; Kenneth Cowen; Bradley Goodwin; Robert Kagann; Chester Spicer; Michael Holdren; Howard T Mayfield; APPLIED RESEARCH ASSOCIATES INC TYNDALL AFB FL
|
 | The Strategic Environmental Research and Development Program (SERDP) has initiated several programs to develop and evaluate techniques to characterize emissions from military aircraft, in order to meet increasingly stringent regulatory requirements. This paper describes the results of a recent field study using extractive and optical remote sensing (ORS) techniques to measure emissions from six F-15 fighter aircraft. Testing was performed between November 14 and 16, 2006 on the trim pad ... |
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| Evaluating Real-Time Platforms for Aircraft Prognostic Health Management Using Hardware-In-The-Loop |
Aug-2008 |
10 pages |
| Authors:
Mitch Wolff; Michael Corbett; Michael Boyd; Peter Lamm; Tommy Baudendistel; KRAUSE (P C) AND ASSOCIATES WEST LAFAYETTE IN
|
| Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion systems and can no longer be neglected or assumed linear in system analyses and prognostic health management (PHM) schemes. The complex models designed to integrate new capabilities have a high computational cost. Hardware-in-the-loop (HIL) is being used to investigate aircraft power systems by using a combination of ... |
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| Hardware-in-the-Loop Power Extraction Using Different Real-Time Platforms (PREPRINT) |
Jul-2008 |
9 pages |
| Authors:
Mitch Wolff; Michael Corbett; John McNichols; Peter Lamm; Caleb Barnes; Thomas Baudendistel; KRAUSE (P C) AND ASSOCIATES WEST LAFAYETTE IN
|
| Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion systems and can no longer be neglected or assumed linear in system analyses. The complex models designed to integrate new capabilities have a high computational cost. Hardware-in-the-loop (HIL) is being used to investigate aircraft power systems by using a combination of hardware and simulations. This paper considers ... |
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| Creep-Rupture and Fatigue Behavior of a Notched Oxide/Oxide Ceramic Matrix Composite at Elevated Temperature |
JUN 2008 |
116 pages |
| Authors:
Barth H. Boyer; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The inherent resistance to oxidation of oxide/oxide ceramic matrix composites makes them ideal for aerospace applications that require high temperature and long life under corrosive environments. The ceramic matrix composite (CMC) of interest in the study is the Nextel (tm) 720/Alumina (N720/A) which is comprised of an 8-harness satin weave of Nextel (tm) fibers embedded in an alumina matrix. One of the top applications for N720/A is in the combustion ... |
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| Heat Transfer Measurements for a Film Cooled Turbine Vane Cascade |
01-May-2008 |
26 pages |
| Authors:
Douglas R Thurman; Philip E Poinsatte; James D Heidmann; ARMY RESEARCH LAB CLEVELAND OH VEHICLE TECHNOLOGY DIRECTORATE
|
| Experimental heat transfer and pressure measurements were obtained on a large scale film cooled turbine vane cascade. The objective was to investigate heat transfer on a commercial high pressure first stage turbine vane at near engine Mach and Reynolds number conditions. Additionally blowing ratios and coolant density were also matched. Numerical computations were made with the Glenn-HT code of the same geometry and compared with the experimental results. We used ... |
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| MEANS 2: Microstructure-and Micromechanism-Sensitive Property Models for Advanced Turbine Disk and Blade Systems |
24 APR 2008 |
8 pages |
| Authors:
Kevin J. Hemker; JOHN HOPKINS UNIV BETHESDA MD OPERATIONS RESEARCH OFFICE
|
| The overall coordinated research effort involved activities in the following areas: (1) Creep and Deformation Structure Characterization Studies of Disk Alloy Rene 104 (ME3), (2) Calculation of Activation Barriers Using Phase Field Dislocation Dynamics, (3) Adaptive computational model of crystal plasticity involving micro-twinning, (4) 3D Atom Probe Analysis of Phase Microstructures. Descriptions of all activities can be found in the annual and final reports submitted and to be submitted by ... |
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| Influence of Residual Stresses on Fretting Fatigue Life Prediction in Ti-6Al-4V (POSTPRINT) |
Jan-2008 |
14 pages |
| Authors:
Patrick J Golden; Dennis Buchanan; Sam Naboulsi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| The objective of this work was to evaluate life prediction methodologies involving fretting fatigue of turbine engine materials with advanced surface treatments. Fretting fatigue tests were performed on Ti-6Al-4V dovetail specimens with and without advanced surface treatments. These tests were representative of the conditions found in a turbine engine blade to disk attachment. Laser shock processing and low plasticity burnishing have been shown to produce deep compressive residual stresses with ... |
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| Wind Farms and Radar |
JAN 2008 |
21 pages |
| Authors:
Michael Brenner; Shelly Cazares; Michael J. Cornwall; Freeman Dyson; Douglas Eardley; Paul Horowitz; Darrell Long; Jeremiah Sullivan; John Vesecky; Peter J. Weinberger; MITRE CORP MCLEAN VA JASON PROGRAM OFFICE
|
| As part of its 2008 Winter Study, JASON was asked by the Department of Homeland Security (DHS) to review the current status of the conflict between the ever-growing number of wind-turbine farms and air-security radars that are located within some tens of miles of a turbine farm. |
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| Second Moment Closure Modeling of Complex Turbulent Flows |
31 DEC 2007 |
47 pages |
| Authors:
Sharath S. Girimaji; TEXAS A AND M UNIV COLLEGE STATION DEPT OF AEROSPACE ENGINEERING
|
| Turbulence subject to unsteady forcing can exhibit novel features that cannot be explained using the well-known steady-turbulence paradigm. Modeling and prediction of such statistically unsteady flows are important in many practical AFOSR applications: turbine flows, wake-flows with vortex shedding, etc. Further, many flow control strategies depend upon the knowledge of unsteady turbulence dynamics to achieve the desired objectives. However, our understanding of unsteadily-forced turbulence dynamics or our ability to predict ... |
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| Design, Construction and Testing of a Prototype Holonomic Autonomous Vehicle |
DEC 2007 |
211 pages |
| Authors:
Kirk N. Volland; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| United States Department of Defense (DoD) autonomous vehicle efforts have concentrated research in areas that support development of unmanned ground and air battlefield vehicles. Little attention has been paid to applying robotics to automate routine tasks. A robotic solution consisting of a prototype holonomic vehicle is proposed to search for, detect, and remove debris that could cause foreign object damage (FOD) to turbine-engine aircraft operated from ships. Holonomic, or omnidirectional, ... |
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| Engine Test Confidence Evaluation System |
13-Sep-2007 |
35 pages |
| Authors:
Michael A Barga; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH TURBINE ENGINE DIV
|
| These briefing charts discuss: test confidence rating (TCR) development for turbine engines, key program milestones, evaluation of test readiness of engine components, instrumentation, assembly and test facilities, establishes quantitative risk assessment, engine TCR flexibility and how it can be tailored to be applicable across many technical areas. |
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| A Comparison of Film Cooling Techniques in a High Speed, True Scale, Fully Cooled Turbine Vane Ring |
JUN 2007 |
69 pages |
| Authors:
Michael J. Umholtz; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| An effort was undertaken to understand the impact of different film cooling configurations in a true scale turbine vane for three proprietary airfoil designs. The measurements for this study were taken at the United States Air Force Turbine Research Facility (TRF). The TRF enabled heat transfer data to be obtained on full scale turbine hardware under realistic engine conditions. The surface heat flux of the turbine blades was analyzed using ... |
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| Tip Clearance Control Using Plasma Actuators |
MAR 2007 |
73 pages |
| Authors:
Scott C. Morris; Thomas C. Corke; NOTRE DAME UNIV IN DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
| This report documents experimental results from a series of experiments using active flow control to improve the performance and efficiency of turbine tip clearance flows. The flow control was based on plasma actuators. Two experimental facilities were used as part of this research project. The first was a low-speed, large-scale turbine cascade using Pak-B turbine blades. The second was a smaller scale, high-speed cascade with low aspect ratio. The active ... |
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| Wireless Damage Monitoring of Laminated CFRP Composites using Electrical Resistance Change |
25 FEB 2007 |
16 pages |
| Authors:
Akira Todoroki; TOKYO INST OF PSYCHIATRY (JAPAN)
|
| It is difficult to detect delamination of rotating composite components like helicopter and wind turbine blades while in-service with a wired system. In the present study, a wireless system using a tiny oscillation circuit for detecting delamination of carbon/epoxy composites is proposed. In this system, a tiny oscillation circuit is attached to the composite component. When delimitation of the component occurs, electrical resistance changes, which causes a change in the ... |
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| Unlubricated Gross Slip Fretting Wear of Metallic Plasma Sprayed Coatings for Ti6A14V Surfaces |
NOV 2006 |
37 pages |
| Authors:
Jr. Hager Carl H.; Jeffrey H. Sanders; Shashi K. Sharma; UNIVERSAL TECHNOLOGY CORP DAYTON OH
|
| Plasma sprayed Al-bronze (Al-Br) or CuNiIn coatings are often applied to protect against fretting wear and extend the operational life of Ti-alloy compressor blades in turbine engines. In order to develop a fundamental understanding of how these coating systems perform under gross slip fretting conditions, bench level fretting wear tests were conducted at room temperature to simulate cold engine startup. Alternative coatings such as plasma sprayed molybdenum and nickel were ... |
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| Performance Impacts Due to Wake in Axil-Flow Turbomachinery (Postprint) |
SEP 2006 |
12 pages |
| Authors:
T. J. Praisner; J. P. Clark; T. C. Nash; M. J. Rice; E. A. Grover; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| Here, we demonstrate that the unsteady losses incurred as turbomachinery wakes mix in downstream rows are a function of the velocity ratio across the downstream row as calculated in the frame of reference of wake generation. Analytical and computational results, compared to measurements of wakes mixing under variable free-stream velocity conditions, reveal that wake-loss alteration is primarily a result of an inviscid dilation of the stream tubes that comprise the ... |
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| Elastomer Impact When Switch-Loading Synthetic Fuel Blends and Petroleum Fuels |
JUL 2006 |
38 pages |
| Authors:
Patsy A. Muzzell; Leo L. Stavinoha; Eric Sattler; Angela Terry; Luis Villahermosa; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
|
| When some elastomer (rubber) compounds, and specifically those used for seals in fuel-wetted components of vehicles and equipment, are suddenly "switch-loaded" from a fuel of given composition to one of a somewhat different composition, swell/shrink issues relating to seal performance may arise, possibly leading to fuel leakage. The key objective of this study was to evaluate what happens to the elastomers with sudden switches from a conventional (petroleum-derived) fuel to ... |
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| Optimization of a Low Heat Load Turbine Inlet Vane |
JUN 2006 |
25 pages |
| Authors:
Jaime J. Johnson; Paul I. King; John P. Clark; Michael J. Flanagan; Ryan P. Lemaire; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| Often there is a distinction between the design of turbomachinery airfoils for aerodynamic performance and durability. However, future aero-engine systems require ever increasing levels of turbine inlet temperature causing the durability and reliability of components to be an ever more important design concern. As a result, the need to incorporate heat transfer predictions into traditional aerodynamic design and optimization systems presents itself. Here, an effort to design an airfoil with ... |
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| A New Paradigm of Fatigue Variability Behavior and Implications for Life Prediction (Preprint) |
JUN 2006 |
23 pages |
| Authors:
S. K. Jha; M. J. Caton; J. M. Larsen; UNIVERSAL TECHNOLOGY CORP DAYTON OH
|
| The treatment of the fatigue variability behavior has traditionally been based on the understanding of the mean-lifetime behavior. With reference to two turbine engine materials, an alpha + Beta titanium alloy and a nickel-based superalloy, it is shown that the traditional approach may not accurately describe the fatigue variability behavior of these materials. Decreases in stress level, or microstructural change directed at increasing the mean lifetime, were found to affect ... |
|
| Hybrid Mole Computer Using Vapor Phase Assembly |
MAY 2006 |
73 pages |
| Authors:
L. R. Harriott; J. C. Bean; M. Stan; N. Swami; VIRGINIA UNIV CHARLOTTESVILLE
|
| The UHV vapor phase assembly of molecules was performed in a stainless steel chamber that is part of a molecular beam epitaxy (MBE) system (shown on the following page) that Professor John Bean brought to the University of Virginia from Bell Labs. This MBE system has two chambers: one that was used for silicon and germanium growth, and the second (referred to as Dep 2 from now on) we engineered ... |
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| Low Temperature Reactivities of Ultra-High Temperature Ceramics (Hf-X System) |
MAR 2006 |
11 pages |
| Authors:
Yigal Blum; SRI INTERNATIONAL MENLO PARK CA
|
| A growing interest in ultra-high temperature ceramics and their aerospace and turbine applications has led to a renewal of activities to fabricate MB2/SiC composites as the materials of choice, because of their high thermal and oxidation resistance stability. Unfortunately, these composites are currently formed by an expensive, size and shape limited hot-press operation at a temperature range of 1900 to 2200 degrees C. The project investigated chemical reactions at and ... |
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| Stress Intensity Solutions of Thermally Induced Cracks in Combustor Liner Hot Spots Using Finite Element Analysis (FEA) |
DEC 2005 |
158 pages |
| Authors:
Donald W. Rhymer; GEORGIA TECH RESEARCH CORP ATLANTA
|
| Developing stress intensity solutions for thermal strain inducing cracking in hot spots is the chief goal of this research. Using finite element analysis (FEA) to model the stress state and crack stress intensities resulting from thermal gradients, a model is needed to represent and predict this cracking and eventual crack arrest in combustor liners in turbine engines. In determining the number of cycles until the crack arrests, the model estimates ... |
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| Fundamentals of Fretting Applied to Anisotropic Materials. High-Temperature Fretting Fatigue of Single-Crystal Nickel |
DEC 2005 |
101 pages |
| Authors:
T. N. Farris; H. Murthy; PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS
|
| The objective of this program was to determine the fatigue crack growth portion of the dissimilar fretting fatigue tests in order to improve the accuracy of the equivalent stress method used to predict the fretting fatigue lives for the single crystal nickel on INl00 attachment fatigue tests. These analyses will give further confidence in the ability to determine endurance limits for attachment fatigue issues associated with these advanced materials. |
|
| Flameless Combustion Workshop |
20 SEP 2005 |
33 pages |
| Authors:
Ephraim Gutmark; GRA-GUTMARK RESEARCH ASSOCIATES CINCINNATI OH
|
| 45 SCIENTISTS AND ENGINEERS FROM 7 COUNTRIES PARTICIPATED IN THE "Flameless Combustion" workshop that was sponsored by Dr. Gabriel Roy of ONR. During the two and half days workshop that took place in Lund, Sweden, on June 19-2 1, the foremost experts in this new field of research, reviewed experimental, computational, and modeling investigations on this topic. Representatives from industry, academia, and government agencies provided their perspectives regarding this emerging ... |
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| Further Evidence of the Effects of Wind Turbine Farms on AD Radar |
12 AUG 2005 |
|
| Authors:
AIR WARFARE CENTRE RAF LINCOLN (UNITED KINGDOM)
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| The Government is supporting the introduction of wind turbine farms within the UK as part of its renewable energy strategy. As a result of the Government's policy, there has been a rapid increase in the number of planning applications for wind turbine farms, including offshore developments. Prior to conducting live flight trials in 2004, the MoD scrutinised planning applications for wind turbine farm developments within 74 km and Line of ... |
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| Optical Pressure and Temperature Mapping |
AUG 2005 |
28 pages |
| Authors:
Jimmy W. Crafton; Larry P. Goss; E. G. Jones; Sergey D. Fonov; INNOVATIVE SCIENTIFIC SOLUTIONS INC DAYTON OH
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| Experimental validation of turbine performance is a challenging task because the high temperatures, scale of the hardware, and gas composition make taking data in a real turbine virtuously impossible. Facilities such as the Air Force Turbine Research Facility (TRF) enable acquisition of data through simulation of the turbine environment. This blow-down facility for testing full-scale turbine hardware allows control of the gas temperature and composition and matches the Reynolds number, ... |
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| The Effects of Wind Turbine Farms on ATC Radar |
10 MAY 2005 |
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| Authors:
AIR WARFARE CENTRE RAF LINCOLN (UNITED KINGDOM)
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| The UK Government supports the introduction of wind turbine farms as part of its alternative energy strategy. However, Ministry of Defense (MoD) guidelines restrict planning consent for wind turbine farms within line of sight (LoS) from Primary Surveillance Radars and in close proximity to Royal Air Force (RAF) Airfields. The validity of these guidelines has been the subject of close scrutiny by the wind farm developers. Consequently, a trial was ... |
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| Weight Analysis of Two-Stage-To-Orbit Reusable Launch Vehicles for Military Applications |
MAR 2005 |
119 pages |
| Authors:
Richard A. Caldwell; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| In response to Department of Defense (DoD) requirements for responsive and low-cost space access, this design study provides an objective empty weight analysis of potential reusable launch vehicle (RLV) configurations. Each two-stage-to-orbit (TSTO) RLV has a fixed payload requirement of 20,000 lbf to low Earth orbit. The propulsion systems considered in this study include pure rocket, pure turbine, rocket-based-combined-cycle (RBCC), and turbine-based- combined-cycle (TBCC). The hydrocarbon dual-mode scramjet (DMSJ) engines ... |
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