| Multi-Scale Modeling for Combined Shock-Shear Initiation of Energetic Solids |
07-Oct-2009 |
25 pages |
| Authors:
Keith A Gonthier; LOUISIANA STATE UNIV BATON ROUGE DEPT OF MECHANICAL ENGINEERING
|
 | Multi-scale interactions between initially planar deformation waves in heterogeneous energetic solids and macro-scale boundaries were computationally examined to characterize wave interaction structures and dissipative heating responsible for combustion initiation. The macro-scale response was described by a continuum theory that accounts for elastic and inelastic volumetric deformation in a thermodynamically consistent manner. The meso-scale response was described by conservation principles and an elastic-viscoplastic constitutive theory to predict contact induced nonlinear deformation ... |
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| Attempts to Create Ball Lightning with Triggered Lightning |
Oct-2009 |
33 pages |
| Authors:
Jonathan D Hill; Martin A Uman; Michael Stapleton; Douglas M Jordan; Alexander M Chebaro; Christopher J Biagi; FLORIDA UNIV GAINESVILLE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| During the 2008 ball lightning experiment, around 100 different material samples were exposed to both relatively continuous (initial stage and inter-stroke continuing current) and to impulsive (return stroke) triggered lightning current. All events with properties similar to those reported by eye-witness and laboratory accounts of ball lightning were produced by slowly varying, relatively low amplitude currents during the initial stage of the triggered-lightning process. No events with sustained luminosity duration ... |
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| Analysis of Silicon Nitride (Si3N4) for Use in a Small Recuperated Turboshaft Engine |
21-Sep-2009 |
8 pages |
| Authors:
Richard L Jr; Stark; Michael J Vick; NAVAL RESEARCH LAB WASHINGTON DC OFF-BOARD COUNTERMEASURES BRANCH
|
| This analysis was performed to determine whether silicon nitride (Si3N4) could be used as a material for fabrication of the Small Recuperated Turboshaft Heavy Fuel Engine (SMART-HFE). Oxidation and volatilization of silicon nitride in the presence of water vapor has proven to be an issue under the conditions of turbine combustion. Through the use of previous research, the recession rates of Si3N4 were predicted for various operating conditions. The volatilization ... |
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| Midwave Infrared Imaging Fourier Transform Spectrometry of Combustion Plumes |
Sep-2009 |
161 pages |
| Authors:
Kenneth C Bradley; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| A midwave infrared (MWIR) imaging Fourier transform spectrometer (IFTS) collected hyperspectral imagery (HSI) of combustion plumes. Exhaust data from a small turbojet engine burning diesel at 300 cc/min was collected at 1/cm. A single-temperature plume model gave fitted temperatures of 811 +/- 1.5 K and 543 +/- 1.6 K near thermocouple probes measuring 719 K and 522 K. Data from a coal-burning stack at 0.25/cm resolution at a range of ... |
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| Cavity Coupled Aeroramp Injector Combustion Study |
Jun-2009 |
76 pages |
| Authors:
Dell T Olmstead; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The difficulties with fueling of supersonic combustion ramjet engines with hydrocarbon based fuels presents many challenges that are currently being tackled by the Air Force Research Lab Propulsion Directorate Aerospace Propulsion Division. As the scramjet engine designs are scaled up, the need for a better solution to supersonic mixing has led to the development of many different styles of fuel injection. An aerodynamic ramp injector has been shown to have ... |
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| Chemical Kinetics Interpretation of Hypergolicity of Ionic Liquid-Based Systems |
01-Apr-2009 |
43 pages |
| Authors:
Laurent Catoire; CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE ORLEANS-LA-SOURCE (FRANCE)
|
| This report results from a contract tasking Centre National de la Recherche Scientifique as follows: The prospect of hypergolically igniting Ionic Liquids (ILs) requires a detailed understanding of the underlying chemical pathways and the reaction mechanisms involved when ILs are treated with NTO or any suitable oxidizer (RFNA, WFNA). The potential to develop hypergolic ignition as a suitable option for space propulsion applications requires gas-phase thermodynamic and chemical kinetic data. ... |
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| Aerospace Toxicology: An Overview |
Apr-2009 |
52 pages |
| Authors:
Arvind K Chaturvedi; FEDERAL AVIATION ADMINISTRATION OKLAHOMA CITY OK CIVIL AEROSPACE MEDICAL INST
|
| The field of aerospace toxicology is composed of aerospace and toxicology. The term aerospace-that is, the environment extending above and beyond the surface of the Earth-is also used to represent the combined fields of aeronautics and astronautics. Aviation is another term frequently and interchangeably used with aerospace and aeronautics and is explained as the science and art of operating powered aircraft. Toxicology is the basic science of poisons. It deals ... |
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| Flame Stabilization and Structure of Reaction Zones |
31-Mar-2009 |
34 pages |
| Authors:
Kevin M Lyons; NORTH CAROLINA STATE UNIV AT RALEIGH OFFICE OF CONTRACTS AND GRANTS
|
| This report discusses recent progress in understanding turbulent, lifted hydrocarbon jet flames and the conditions under which they stabilize, which has implications for both gaseous- and spray-burner design. Experiments are discussed which support the importance of a variety of effects, including partial premixing, local extinction, streamline divergence, air co-flow and large-scale structures. Specifically, advances in flame hystersis and propagation are reported, which have helped clarify the overall understanding of combustion ... |
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| Tunable Diode Laser Absorption Spectroscopy Verification Analysis for Use in the Combustion Optimization and Analysis Laser Laboratory |
Mar-2009 |
125 pages |
| Authors:
Christina R Serianne; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The AFIT Combustion Optimization and Analysis Laser (COAL) laboratory has state-of-the-art laser diagnostic capability for combustion process. The research for this thesis served to enhance the COAL lab's capability. Currently, there are no known commercially available tunable diode lasers that produce Ultra-Violet radiation required for this analysis. Sum-frequency generation at 313.5 nm was utilized for high speed OH absorption and temperature measurements at a rate of 2kHz. The Tunable Diode ... |
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| Ceramic Matrix Composite Characterization Under a Combustion and Loading Environment |
Mar-2009 |
120 pages |
| Authors:
Andrew R Nye; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Lightweight materials that can withstand high temperatures and corrosive environments are constantly sought after in the aerospace industry, typically for Gas Turbine Engine (GTE) application. These materials need to retain their strength throughout the long service period they would see in the combustor and turbine components of a GTE. One material that is ideal for these types of applications is an oxide/oxide Ceramic Matrix Composite (CMC). The fatigue behavior of ... |
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| Development of Implicit Compact Methods for Chemically Reacting Flows |
28-Feb-2009 |
56 pages |
| Authors:
Mitchell D Smooke; Marshall Long; YALE UNIV NEW HAVEN CT DEPT OF MECHANICAL ENGINEERING
|
| This project has focused on the design of numerical algorithms that are well suited to the computation of time-dependent chemically reacting flows with finite-rate kinetics and detailed transport. High order compact finite differences have been used to discretize the spatial operators since the spectral-like resolution of the small scales makes it feasible to conduct accurate, long-time computations of multi-dimensional flames burning real fuels. In view of the stiffness of the ... |
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| Spectroscopic Characterization of Reactive Intermediates Relevant to Supersonic Combustion |
28-Feb-2009 |
18 pages |
| Authors:
Mark A Johnson; YALE UNIV NEW HAVEN CT DEPT OF CHEMISTRY
|
| Our program specializes in the spectroscopic characterization of molecular ions and reactive intermediates in ion-molecule reactions, and is closely integrated with ongoing activities at the AFRL Space Vehicles Directorate to determine the temperature dependence of ion-molecule and ion-ion reaction kinetics which are important in high-velocity (e.g., scramjet) combustion and re-entry plasma. Our role in this collaboration was to provide experimental benchmarks for bond energies, structures, and stationary points in the ... |
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| Computational Prediction of Kinetic Rate Constants |
Feb-2009 |
27 pages |
| Authors:
Mark Ponton; Rodney J Bartlett; ACES QC LC GAINESVILLE FL
|
| The objective of this STTR has been to develop tools to make the evaluation of rate constants for gas phase reactions routine for many modest sized molecules. such quantities are critical input to atmospheric and combustion models. they also provide critical information to designing procedures to destroy stock piles of nerve agents, and other waste products. However, it is often very difficult to experimentally measure such rate constants, making 'predictive' ... |
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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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| Single-Beam Coherent Anti-Stokes Raman Scattering Spectroscopy of N2 Using a Shaped 7 fs Laser Pulse |
Jan-2009 |
4 pages |
| Authors:
Sukesh Roy; James R Gord; Paul Wrzesinski; Dmitry Pestov; Tissa Gunaratne; Marcos Dantus; SPECTRAL ENERGIES LLC DAYTON OH
|
| The feasibility is explored by single-beam coherent anti-Stokes Raman scattering CARS spectroscopy of gas-phase diatomic molecules related to combusting flows, with implications for gas-phase thermometry. We demonstrate CARS of gas-phase N2 using a shaped 7 fs laser pulse, investigate the dependence of the CARS signal on the total pressure of the probed environment, both in pure N2 and in mixtures with Ar, discuss the observed signal-to-noise ratio, and suggest improvements ... |
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| Promising New High-Explosives: Triaminoguanidinium (TAG) and Dinitramide (DN) Salts |
Dec-2008 |
11 pages |
| Authors:
Thomas M Klapoetke; Norbert Mayr; Joerg Stierstorfer; LUDWIG-MAXIMILIANS UNIV MUNICH (GERMANY) DEPT OF CHEMISTRY AND BIOCHEMISTRY
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| High nitrogen energetic materials with astonishing thermal behaviors and performances were synthesized by different metathesis reactions. Particularly the new compound triaminoguanidinium 1-methyl-5-nitriminotetrazolate (TAG-1 Me-AtNO2, 4) shows great explosion performance and may be an alternative to commonly used and toxic RDX. An improved synthesis for the promising energetic compound 4 is also presented. The new compound TAG2-OD (trianinoguanidinium 3,3'-bis-1,2,4-oxadiazol-5-onate, 7) with an N-content of 60% and a relatively low isobaric (20 ... |
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| Investigations of the Energy Release Mechanisms of Aluminum-Nickel Reactive Material System |
Dec-2008 |
9 pages |
| Authors:
Ravindra Pandey; Barrie E Homan; Kevin L McNesby; John Ritter; Joseph Colburn; Andrew Brant; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Reactive materials (RM) are a wide class of energetic materials with unique characteristics that can enable highly lethal munitions along with other applications. Most of the existing information on the behavior of these materials is phenomenological in nature with little evidence as to the initiation and reaction mechanisms at play, making full exploitation of the potential lethality gains difficult. To remedy this situation, a more fundamental understanding of the initiation ... |
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| Critical Evaluation and Modeling of Solid Propellant Dark Zone Experiments |
Dec-2008 |
9 pages |
| Authors:
William R Anderson; Nancy E Meagher; John A Vanderhoff; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The dark zone (DZ) region is a curious phenomenon in low pressure (approximately 5 - 100 atm) flames of combusting solid propellants. The chemistry controlling low pressure DZ structure has recently been shown to be crucial to combustion properties of these propellants at higher pressures, as in guns. The present work focuses on quantitative testing of a model of DZ structure based on a detailed chemical mechanism. A critical survey ... |
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| Computer-Based Adaptation Tool for Advanced Diesel Engines Used in Military Applications |
04-Sep-2008 |
7 pages |
| Authors:
Naeim A Henein; Dinu Taraza; Nabil Chalhoub; WAYNE STATE UNIV DETROIT MI OFFICE OF RESEARCH AND SPONSORED PROGRAMS
|
| The main goal of the project was the development a computer code capable to simulate the operation of a multi-cylinder common rail diesel engine. The code should be used in investigating the possibilities of a commercial engine to be adapted for military applications by increasing the engine output while reducing fuel consumption and assure safe operation of the engine. In the process of developing the simulation model and the corresponding ... |
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| The Key Role of Surface Tension in the Theory of Bubble-Assisted Explosion/Combustion Triggering |
01-Sep-2008 |
20 pages |
| Authors:
Michael Grinfeld; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| We have revised the classical and widely accepted theory of (Bowden, F. P.; Yoffe, A. D. The Initiation and Growth of Explosion in Liquids and Solids; Cambridge University Press: New York, NY, 1952) explaining the initiation of explosion/combustion by means of adiabatic compression of the dissolved gaseous bubbles within condensed liquid substances. The main thrust of our study is to explore the role of surface tension at the interface liquid ... |
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| An Integrated Ignition and Combustion System for Liquid Propellant Micro Propulsion |
26-Jun-2008 |
|
| Authors:
Vigor Yang; Richard A Yetter; I A Aksay; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MECHANICAL AND NUCLEAR ENGINEERING
|
 | Liquid monopropellant microthrusters utilizing electrolytic ignition were designed, fabricated, and analyzed. Low temperature co-fired ceramic tape technologies were used initially to fabricate microscale burners in order to evaluate the applicability of the technology to high temperature combustion systems. Microscale diffusion flames were stabilized in the burners, and optical spectroscopy measurements were performed to characterize the flame behavior. The low temperature co-fired ceramic tape technologies were then applied to the fabrication ... |
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| Launch Survivability Analysis of On-board Components of the Extended Area Protection and Survivability (EAPS) Projectile System |
JUN 2008 |
46 pages |
| Authors:
Michael M. Chen; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| This report focuses on the ability of on-board electronics generally required for precision projectiles to survive pressure waves that occur in early combustion phase for most propelling charges because of pressure imbalance in the chamber. The modeling of pressure waves was achieved by a deterministic transient excitation followed by a stochastic approach. The responses of the on-board electronic components were found to be significant when pressure waves were taken into ... |
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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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| Gasification Characterization of Ionic Liquids as Propellants |
25 MAY 2008 |
18 pages |
| Authors:
Chung K. Law; PRINCETON UNIV NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The objective of the program was to understand and quantify the gasification and oxidation characteristics of droplets of ionic liquids (ILs) in environments of various temperatures and oxygen concentrations. Using 1-ethyl-3- methylimidazolium dicyanamide as a surrogate IL, extensive experiments were performed on suspended and freely falling droplets, and on relating the droplet combustion behavior to the evolution of its internal temperature. Results show that, because of the extreme low volatility ... |
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| Quenching Dynamics of Electronically Excited Hydroxyl Radicals |
19 MAY 2008 |
6 pages |
| Authors:
Marsha I. Lester; PENNSYLVANIA UNIV PHILADELPHIA
|
| Collisional quenching of electronically excited OH radicals by molecular partners has been investigated over the past 25 years, principally by evaluating the quenching cross sections for partners of aeronautical, atmospheric, and/or combustion relevance. Yet little is known about the outcome of these electronic quenching events, except that they facilitate the efficient removal of OH from the excited Alpha 2sigma+ electronic state by introducing nonradiative decay pathways. Most recently, we carried ... |
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| Computational Equipment for Support of Air Force Sponsored Programs for the Design of Advanced and Miniaturized Explosive and Advanced Propellant Systems |
02 MAY 2008 |
6 pages |
| Authors:
D. S. Stewart; John D. Buckmaster; Thomas L. Jackson; ILLINOIS UNIV AT URBANA-CHAMAPIGN
|
| This grant funded the acquisition of a 128 node/256 processor cluster computer that now supports the computational needs of the combined, Air Force-sponsored research groups of Prof. D. Scott Stewart (PI) in Mechanical Science and Engineering, (MechSE), Prof. John Buckmaster (Co-PI) in Aerospace Engineering (AE), and Thomas L. Jackson (Co-PI) in Computational Science and Engineering (CSE), all at the University of Illinois. The combined Stewart/Buckmaster/Jackson group continues to support advanced ... |
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| Effects of a Variable-Phase Transverse Acoustic Field on a Coaxial Injector at Subcritical and Near-Critical Conditions (Preprint) |
01-May-2008 |
12 pages |
| Authors:
Juan I Rodriguez; Ivett A Leyva; Douglas Talley; Bruce Chehroudi; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| An experimental study that focuses on the effects of a variable transverse acoustic field on an N2 shear coaxial jet is presented. The coaxial jet is exposed to different acoustic conditions by varying the phase between two acoustic sources. The main objective of this investigation is to analyze the effect of transverse acoustic forcing with variable phase on the magnitude of the inner-jet dark-core length. The coaxial jet is exposed ... |
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| Reactions of PO(x)Cl(y)-ions with O(2)(a1-delta-g), H(2)O, and Cl(2) at 298 K |
10-Mar-2008 |
5 pages |
| Authors:
A A Viggiano; Anthony J Midey; Itzhak Dotan; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| The rate constants and product branching ratios for the reactions of phosphorus oxychloride anions, POxCly for x = 1-2 and y = 1-3, with 02(a'Ag), C12 and H20 have been measured in a selected ion flow tube (SIFT) at 298 K. A mixture of 02(a'Ag) in 02 has been produced using a recently designed chemical singlet oxygen generator (sparger) with an emission detection scheme adopted previously in our laboratory. The ... |
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| Oxide Coatings in Aero-Turbine Engines |
28 FEB 2008 |
3 pages |
| Authors:
Anthony G. Evans; John W. Hutchinson; CALIFORNIA UNIV SANTA BARBARA
|
| Oxide coatings used for various components in the hot section of aero-turbine engines experience temperature gradients at various stages during their flight cycle. One gradient exists during steady-state, due to the combination of the combustion environment next to the free surface and internal cooling of the underlying superalloy substrate. Other gradients develop during cooling of the surface when engine power is reduced. It is argued that deep delaminations, when observed ... |
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| Tactical Wheeled Vehicle Tire Fire Extinguishing Agent |
01-Jan-2008 |
11 pages |
| Authors:
Eric Wilson; Alex Ordway; NAVAL AIR WARFARE CENTER WEAPONS DIV CHINA LAKE CA
|
| The overall objective of the Tactical Wheeled Vehicle Tire Fire Extinguishing Agent test series is to provide enhanced fire fighting capability to warfighters. Vehicles suffering from mobility loss due to burning tires require a hand held extinguisher to put out the fire and prevent fire spread past the wheel well. The previously used agent (PKP) was not effective at preventing fire reflash after the fire was out. This report is ... |
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| Plasma-Propellant Interaction Studies |
20 DEC 2007 |
24 pages |
| Authors:
Stefan T. Thynell; Thomas A. Litzinger; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MECHANICAL ENGINEERING
|
| This report describes research focused on the interactions between a plasma and a solid propellant. The specific issues addressed include the effects of radical and neutral species as well as radiative heat transfer on the ignition and combustion of double-base propellants. A wide variety of measurements have been conducted using a broad range of diagnostic tools, such as a triple-quadrupole mass spectrometer, special heat flux gages, high-speed cameras, as well ... |
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| Thermal Coating for Insensitive-Munitions Technologies |
NOV 2007 |
40 pages |
| Authors:
Pauline Smith; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The U.S. Army is evaluating coatings for ammunition containers. An intumescent coating system for fire and heat protection is required for packaged 60-mm mortar cartridges to pass fast cookoff requirements. An intumescent coating has all the properties of ordinary paint; furthermore, this coating will not sustain combustion. Consequently, it will not burn and will provide a high degree of protection to the subsurface. Upon exposure to flame or heat, it ... |
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| Synthesis of Nanostructured LaB6 Powders |
25-Oct-2007 |
10 pages |
| Authors:
Olivia A Graeve; NEVADA UNIV RENO
|
| Nanocrystalline powders of LaB6 with an average crystallite size of 20 nm, as determined from x-ray diffraction analysis, have been obtained using a combustion synthesis technique that makes use of lanthanum nitrate, boron, and carbohydrazide as precursors. The optimum fuel-to-oxidizer ratio was found to be 0.25, which is quite low compared to typical combustion synthesis experiments. The powders are phase-pure except for about a 3 mol% contamination of LaBO3. |
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| Phenomenological Model for Infrared Emissions from High-Explosive Detonation Fireballs |
SEP 2007 |
185 pages |
| Authors:
Kevin C. Gross; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| Time-resolved infrared spectra were recently collected via a Fourier-transform spectrometer (FTS) from the detonation fireballs of two types of conventional military munitions (CMM) as well as uncased TNT and four types of enhanced novel explosives (ENEs). The CMM spectra are dominated by continuum emission, and a single-temperature Planckian distribution, modified for atmospheric attenuation, captures most of the variation in the data. Some evidence of selective emission is identified by systematic ... |
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| Physical and Chemical Processes in Flames |
SEP 2007 |
19 pages |
| Authors:
Chung K. Law; PRINCETON UNIV NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The objective of the present program was to study the structure and response of laminar premixed and nonpremixed flames with emphases on effects of high pressure, flame/flow unsteadiness, and chemistry. Studies on flame dynamics show strong coupling between the intrinsic flamefront hydrodynamic cellular instabilities and the diffusional/thermal cellular or pulsating instabilities, for mixture Lewis numbers that are respectively smaller or larger than unity. Linear and nonlinear stability analyses on diffusion ... |
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| Validation of the AFIT Small Scale Combustion Facility and OH Laser-Induced Fluorescence of an Atmospheric Laminar Premixed Flame |
SEP 2007 |
98 pages |
| Authors:
Stephen J. Koether; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Construction in the AFIT combustion facility is complete and the objective of this report is to explain the steps taken to make the laboratory operational. The infinite radius Ultra-Compact Combustor (UCC) sectional model has been delivered and is fully installed with all fuel, air and instrument lines. Every major system in the lab has been tested and is functioning properly. Laboratory operating procedure has been established to ensure both safety ... |
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| Energy Efficient Transient: Plasma Ignition: Physics and Technology |
30 AUG 2007 |
18 pages |
| Authors:
M. Gundersen; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF ELECTRICAL ENGINEERING AND ELECTROPHYSICS
|
| The project has conducted basic studies of flame ignition collaborative studies of pulse detonation ignition, and preliminary studies of fundamental issues relevant to the application of transient plasma as an ignition source for Air Force high-speed aircraft applications. Preliminary basic science experiments have been conducted at the Air Force Research Laboratory (AFRL) using planar laser-induced fluorescence (PLIF) for investigation of radical production and ignition delay. Very strong enhancement of radical ... |
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| Investigation of Non-Conventional Bio-Derived Fuels for Hybrid Rocket Motors |
AUG 2007 |
144 pages |
| Authors:
Scott G. Putnam; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Non-conventional bio-derived fuels have been evaluated for use in hybrid rocket motors. Tests were conducted at combustion pressures in the range of 100 - 220 psig and thrust levels of 40 - 170 newtons. Beeswax was tested with oxygen as the oxidizer and showed a regression rate at least three times as high as traditional hybrid propellant combinations such as hydroxyl-terminated polybutadiene (HTPB) and liquid oxygen (LOX). This provides the ... |
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| The Effect of Steady Fluid Motion on One-Dimensional Wave Propagation (Postprint) |
AUG 2007 |
13 pages |
| Authors:
Barry Kiel; Reza Kashani; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| Reduced order modeling of thermoacoustic instabilities involves the coupled modeling of the wave propagation in the combustion chamber and the unsteady heat release. In many combustion systems the Mach number is low enough that the effect of the fluid motion on the wave propagation can be ignored. Ignoring the fluid motion results in the use of the wave equation to model the wave motion in the combustion chamber. In a ... |
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| Non-Reacting and Combusting Flow Investigation of Bluff Bodies in Cross Flow (Postprint) |
AUG 2007 |
13 pages |
| Authors:
Barry Kiel; Kyle Garwick; Amy Lynch; James R. Gord; Terrence Meyer; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| This paper is the first in a series of papers studying the behavior of bluff body stabilized flames. In this research a combination of Laser Doppler Velocimetry (LDV), and High Speed Imaging are used to investigate these flames. LDV data taken over several non-combusting operating conditions detail the recirculation zone behind the bluff body as well as the effect of inlet conditions on the Karman Street vortex shedding that occurs. ... |
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| Operability and Efficiency Performance of Ultra-Compact, High Gravity (g) Combustor Concepts (Postprint) |
JUL 2007 |
11 pages |
| Authors:
Joseph Zelina; Roger T. Greenwood; Dale T. Shouse; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| This paper presents a parametric design study of the Ultra-Compact Combustor (UCC), a novel design based on trapped-vortex combustor (TVC) work that uses high swirl in a circumferential cavity to enhance reaction rates via high cavity g-loading on the order of 3000 g's. Increase in reaction rates translates to a reduced combustor volume. Three combustor geometric features were varied during experiments which included (1) high-g cavity flame-holding method, (2) high-g ... |
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| Experimental Study of Cavity-Strut Combustion in Supersonic Flow (Postprint) |
JUL 2007 |
16 pages |
| Authors:
K. -Y. Hsu; Campbell D. Carter; M. R. Gruber; T. Barhorst; INNOVATIVE SCIENTIFIC SOLUTIONS INC DAYTON OH
|
| An experimental investigation of cavity-based flameholders with strut injectors in a supersonic flow is reported. In this ongoing research program, emphases are placed on understanding cavity-based flameholders and providing alternative methods for improving overall combustor performance in scramjet engines. Three different struts with fuel injectors are mounted near the cavity leading edge to study flame propagation and ignition of fuel in the core flow region. OH-PLIF is used to identify ... |
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| Dark Core Analysis of Coaxial Injectors at Sub-, Near-, and Supercritical Pressures in a Transverse Acoustic Field (Postprint) |
13 JUN 2007 |
19 pages |
| Authors:
Ivett A. Leyva; Douglas Talley; Bruce Chehroudi; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| An experimental study on the effects of an externally-imposed transverse acoustic field in a N2 shear coaxial jets at sub-, near-, and supercritical pressures is presented. Such fields and their interaction with the jets (i.e., breakup, mixing, etc.) are believed to play a critical role during combustion instabilities in liquid rocket engines. The shear coaxial injector used here is similar to those used in cryogenic liquid rockets. By using N2 ... |
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| Army Research Office and Air Force Office of Scientific Research Contractors' Meeting in Chemical Propulsion Held in Boulder, Colorado on June 11-13, 2007 |
JUN 2007 |
163 pages |
| Authors:
Ralph Anthenien; Julian M. Tishkoff; AIR FORCE OFFICE OF SCIENTIFIC RESEARCH ARLINGTON VA
|
| The Air Force Office of Scientific Research (AFOSR) program in combustion and diagnostics currently is focused on five areas of study: high-speed propulsion, turbulent combustion, diagnostics, supercritical fuel behavior, and plasma-enhanced combustion. An assessment of major research needs in each of these areas is presented. |
|
| Ground Vehicle Power and Mobility Overview |
30 MAY 2007 |
28 pages |
| Authors:
Jennifer Hitchcock; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
|
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| Condensed-Phase Reactions of Energetic Ionic Liquids Under Different Ignition Stimuli |
20 MAR 2007 |
17 pages |
| Authors:
Thomas A. Litzinger; Stefan T. Thynell; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| The experimental work conducted under this program was designed to provide new insight into condensed-phase reactions leading to ignition of ionic liquids. The objectives of the work were: (1) to identify the initiation and secondary reactions in the condensed phase that lead to ignition and combustion, (2) to understand the effects of the structure of the cation on these reactions, and (3) to determine the effects of the type of ... |
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| Advances on Propulsion Technology for High-Speed Aircraft. Volume 1 |
MAR 2007 |
|
| Authors:
VON KARMAN INST FOR FLUID DYNAMICS RHODE-SAINT-GENESE (BELGIUM)
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| The Final Proceedings for Advances in Propulsion Technology for High-Speed Aircraft, 12 March 2007-15 March 2007. The demand for supersonic vehicles is believed to boost in the incoming years. This VKI/RTO lecture series will review the current state of the art of high speed propulsion for both airplanes and space launchers. Hypersonic air-breathing vehicles technology benefits and challenges will be discussed, with particular attention to the recent hypersonic activities in ... |
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| Advances on Propulsion Technology for High-Speed Aircraft. Volume 2 |
MAR 2007 |
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| Authors:
VON KARMAN INST FOR FLUID DYNAMICS RHODE-SAINT-GENESE (BELGIUM)
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| The Final Proceedings for Advances in Propulsion Technology for High-Speed Aircraft, 12 March 2007-15 March 2007. The demand for supersonic vehicles is believed to boost in the incoming years. This VKI/RTO lecture series will review the current state of the art of high speed propulsion for both airplanes and space launchers. Hypersonic air-breathing vehicles technology benefits and challenges will be discussed, with particular attention to the recent hypersonic activities in ... |
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| Laser Diagnostics for Reacting Flows |
30 JAN 2007 |
72 pages |
| Authors:
Ronald K. Hanson; STANFORD UNIV CA HIGH TEMPERATURE GASDYNAMICS LAB
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| Advanced optical diagnostic techniques relevant to propulsion were investigated. The techniques studied were based on laser spectroscopy, with emphasis on spectrally-resolved absorption and laser-induced fluorescence (LIF). Laser sources included tunable cw near-infrared diode lasers and tunable (or fixed-wavelength) pulsed lasers operated at ultraviolet (UV) or infrared (IR) wavelengths. The cw lasers were spectrally narrow, allowing study of innovative diagnostics based on spectral lineshapes, while the pulsed lasers provided intense bursts ... |
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| Combustion Light Gas Gun Technology Demonstration |
23 JAN 2007 |
148 pages |
| Authors:
D. Kruczynski; D. Massey; R. Milligan; E. Vigil; B. Landers; M. Meneguzzi; UTRON INC MANASSAS VA
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| The Combustion Light Gas Gun, or CLGG, has been investigated for over ten years. During this time, the research has shown that the technology provides a minimum of 30% more muzzle energy than advanced solid propellent guns which translates to significant advantages in range and/or throw weight. For the Navy Barrage round fired from a 155mm bore CLGG, the predicted range is up to 200 nm, sufficient to provide effective ... |
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