| A Physical Hypothesis for the Combustion Instability in Cryogenic Liquid Rocket Engines (Preprint) |
21-Apr-2008 |
19 pages |
| Authors:
Bruce Chehroudi; ENGINEERING RESEARCH AND CONSULTING INC (ERC INC) EDWARDS AFB CA
|
 | In this work, the author would like to portray a sketch of a unified physical picture to describe the coupling nature/strength between the chamber acoustics and the injectors. This new perspective is achieved through a physically intuitive argument combined with previously published test results for two popular injector designs, namely, coaxial and impinging jets. For the impinging-jets injectors, it is shown that the dynamic behavior of the dark-core (or breakup) ... |
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| Nanojets: Electrification, Energetics, Dynamics, Stability and Breakup |
NOV 2007 |
53 pages |
| Authors:
Uzi Landman; GEORGIA INST OF TECH ATLANTA SCHOOL OF PHYSICS
|
| The research during this 6 month grant was devoted to finalizing our work on the effect of electric fields on dielectric nanodroplets, as may be found during the breakup of electrified nanojets and colloidal thrusters. In our extensive molecular dynamics simulation, preformed for a 10nm droplet made of formamide molecules, the response of the nano-droplet to uniform electric fields was explored. |
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| Preliminary Results on Coaxial Jets Spread Angles and the Effects of Variable Phase Transverse Acoustic Fields (Preprint) |
21 AUG 2007 |
15 pages |
| Authors:
Ivett A. Leyva; Douglas Talley; Juan I. Rodriguez; Bruce Chehroudi; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| An experimental study on the jet spreading angle of N2 shear coaxial jets at sub-, near-, and supercritical pressures is presented. The jet spreading angle is an important parameter which characterizes the mixing between two flows forming a shear layer. The present results are compared with previous experimental data, CFD results, and theoretical predictions. The angle measurements are made directly from at least 20 backlit images. The shear coaxial injector ... |
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| Liquid Breakup in Dense Sprays |
21 FEB 2006 |
17 pages |
| Authors:
MICHIGAN UNIV ANN ARBOR DIV OF RESEARCH
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| Active Control Strategies to Optimize Supersonic Fuel-Air Mixing for Combustion Associated with Fully Modulated Transverse Jet in Cross Flow |
27 DEC 2005 |
63 pages |
| Authors:
C. Ghenai; G. P. Philippidis; C. X. Lin; FLORIDA INTERNATIONAL UNIV MIAMI APPLIED RESEARCH CENTER
|
| A 76 mm x 76 mm supersonic wind tunnel with variable Mach Numbers (M = 1.5 - 4) was designed and set up. The wind tunnel could support both non-reacting fuel-air mixing and combustion. A back pressure flap was added at the downstream end of the diffuser for dual mode (subsonic- supersonic) combustion studies. A high-speed imaging system was used for the visualization of pure liquid jet, aerated liquid jet ... |
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| Method for the Production of Conductive Polymer Nanofibers and Nanofiber Composites |
DEC 2004 |
3 pages |
| Authors:
G. A. Gaddy; Matthew S. Bratcher; Joseph M. Deitzel; C. Krauthauser; Sean R. Stevens; Chris Ziegler; Frederick L. Beyer; Max D. Alexander; Brandon Black; Hilmar Koerner; AIR FORCE RESEARCH LAB TYNDALL AFB FL MATERIALS AND MANUFACTURING DIRECTORATE
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| Palladium ion-containing polyamic acid nanofibers have been made using an electrospinning process. The fibers are approx. 500 nm in size and have high aspect ratios. Electrospinning is a process which uses an electrostatically driven jet of polymer fluid (solution or melt) to generate submicron - nanometer scale diameter polymer fibers. Typically, a voltage is applied to the fluid which is pumped through a spinnerette. The spinnerette can be a glass ... |
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| Understanding Injection Into High Pressure Supercritical Environments |
09 OCT 2003 |
37 pages |
| Authors:
B. Chehroudi; D. Talley; W. Mayer; R. Branam; J. J. Smith; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| This paper summarizes the results of systematic research programs at both the DLR and the AFRL which began nearly ten years ago. The research is aimed at improving the understanding of atomization, mixing, and combustion processes associated with coaxially injected liquid propellant rocket engines. Cold flow studies are imperative for investigations without the complexities introduced with combustion. Initial studies utilized liquid nitrogen (LN2) without a co-flow stream into a chamber ... |
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| Microscopic Modeling of Tribochemical Processes Vapor-Phase Lubrication and Nanotribology in MEMS |
MAY 2003 |
38 pages |
| Authors:
Uzi Landman; GEORGIA INST OF TECH ATLANTA SCHOOL OFPHYSICS
|
| Research activities supported by this grant focused on the following main topics: 1. Investigations of fluid flow through nanometer scale nozzles (nanojets), aiming at the development of miniaturized injectors in NEMS (Nano Electro Mechanical Systems). 2. Studies of the effects of surface roughness on the properties of confined fluids, pertaining to tribological and lubrication processes in nano-scale junctions. 3. Development of large-scale computer-based molecular dynamics simulation aimed at investigations of ... |
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| High Power Gas-Discharge and Laser-Plasma Based EUV Sources |
17 JUL 2002 |
7 pages |
| Authors:
Frank Flohrer; Kai Gaebel; Diethard Kloepfel; Peter Koehler; Imtiaz Ahmad; XTREME TECHNOLOGIES GMBH JENA (GERMANY)
|
| In this paper we discuss new results from investigations on high power EUV sources for micro-lithography based on gas discharge produced plasmas and laser produced plasmas. The EUV development is performed at XTREME technologies OmbH, a joint venture of Lambda Physik AG, Gottingen, and Jenoptik LOS GmbH, Jena. For gas discharge EUV sources we report data based on Xenon filled Z-pinches. Prototypes of the EUV source achieve an EUV output ... |
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| Preliminary Visualizations of Acoustic Waves Interacting with Subcritical and Supercritical Cryogenic Jets |
MAY 2002 |
7 pages |
| Authors:
Bruce Chehroudi; Doug Talley; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
| The effect of large amplitude acoustic waves on subcritical and supercritical cryogenic jets was studied. A general trend was observed that acoustic waves cause the time averaged cross section of the jet to flatten in a direction where the minor axis becomes aligned with the direction of propagation of the waves. It was also found that the presence of acoustic waves shortened the breakup length of the jets compared with ... |
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| The Fractal Geometry of Round Turbulent Cryogenic Nitrogen Jets at Supercritical Pressures |
MAR 2002 |
13 pages |
| Authors:
Bruce Chehroudi; Doug Talley; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
| Box-counting and EDM methods were used to measure the fractal dimension of round turbulent cryogenic nitrogen jets at pressures ranging from subcritical to supercritical pressures. Both method produced similar trends, with close quantitative agreement for a suitably small box-counting scale. At subcritical pressures, the fractal dimension was found to be consistent with the fractal dimension of a spray in the 2nd wind-induced atomization regime. The fractal dimension tended to increase ... |
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| Initial Results from a Cryogenic Coaxial Injector in an Acoustic Field |
09 JAN 2002 |
9 pages |
| Authors:
B. Chehroudi; D. Davis; D. Talley; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| A coaxial injector was made to inject liquid nitrogen (LN2) with a coflow of gaseous nitrogen (GN2) in its annular region as part, of a program to better understand the nature of the interaction between acoustic waves and liquid fuel jets in cryogenic rocket engines. The LN2 was injected into a room temperature high-pressure chamber having optical access on its sides. A piezo- siren capable of generating sound waves with ... |
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| Fluid Mechanics and Rheology of Liquid Crystalline Polymer Flows: Fundamental Science and Technological Applications |
14 OCT 2001 |
9 pages |
| Authors:
Qi Wang; INDIANA UNIV INDIANAPOLIS
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| This report summarizes the research work done during the period covered by the AFOSR grant. The PI investigated the flow-orientation coupling and pattern formation in flows of liquid crystalline polymers. Both short and long range elasticity due to the microstructure formation in the macromolecular material can impact on the flow stability. Various experimental phenomena have been modeled by the hydrodynamic theory developed in the project. Several new theories for polymer-liquid ... |
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| Visual Characteristics and Initial Growth Rates of Round Cryogenic Jets at Subcritical and Supercritical Pressures |
MAR 2001 |
22 pages |
| Authors:
B. Chehroudi; D. Talley; E. Coy; ENGINEERING RESEARCH AND CONSULTING INCEDWARDS AFB CA
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| The visual characteristics and initial growth rates of round cryogenic jets injected into subcritical and supercritical pressures were studied. We found that the jet exhibits liquid-like and gas-like characteristics at subcritical and supercritical pressures, respectively. Explanations are offered. The jet spreading angle at supercritical pressures has been demonstrated to agree quantitatively with the theoretical spreading angle of incompressible but variable density turbulent gas jets, the first time more than a ... |
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| The Behavior of Cryogenic Shear Layers Under Supercritical Conditions |
MAR 2001 |
8 pages |
| Authors:
B. Chehroudi; R. Cohn; D. Talley; ENGINEERING RESEARCH AND CONSULTING INCEDWARDS AFB CA
|
| Recent experience gained at AFRL with the injection of cryogenic fluids into high back-pressures is summarized. In the experimental investigations described, a jet of a cryogenic fluid, typically liquid N2, is injected into a chamber whose ambient pressure is varied to values exceeding the critical pressure of the injectant. The structure of the jet and the shear layer between the jet and the ambient has been examined. Results from visualization, ... |
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| Experiences on Cryogenic Injection under Supercritical Condition |
22 MAY 2000 |
10 pages |
| Authors:
Bruce Chehroudi; Doug Talley; R. Cohn; ENERGY RESEARCH CONSULTANTS INC LAGUNA HILLS CA
|
| Experience learned at the AFRL on injection of cryogenic jets into sub- and supercritical conditions using shadowgraphy and Raman scattering measurements are presented here. Metamorphic behavior of the jet boundary undergoing disruption has been shown to occur near the critical point of the injected fluid. At subcritical pressures, formations of droplets and ligaments are seen, resembling a second wind-induced liquid-jet breakup. The jet is incapable of reaching the classical full ... |
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| Spray Generation |
SEP 1999 |
100 pages |
| Authors:
Angel G. Salinas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This is an experimental investigation of the ligaments and drops generated at the free surface of liquid wall jets and liquid axisymmetric jets flowing over sand and polystyrene (beads) roughed surfaces. Experiments were conducted with freshwater and Eulerian and Lagrangian methods of description were used in the analysis. Measurements were made with three different high- speed imagers and two different pulsating laser systems and analyzed ... |
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| The Effect of Turbulence on Droplet Drag, Dispersion, Vaporization and Secondary Breakup in Diesel Fuel Sprays |
15 JUL 1999 |
6 pages |
| Authors:
D. A. Santavicca; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MECHANICAL ENGINEERING
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| Results are presented from an experimental study of droplet phenomena in diesel engine and gas turbine combustor simulated flows. Three specific phenomena have been studied: (1) the use of exciplex fluorescence to characterize the vaporization of liquid droplets in unsteady flows, (2) the enhanced secondary breakup of liquid droplets in flows with intense turbulence, and (3) the behavior of liquid jets injected into supercritical environments. |
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| Fractal Geometry and Growth Rate Changes of Cryogenic Jets Near the Critical Point |
14 JUN 1999 |
16 pages |
| Authors:
B. Chehroudi; D. Talley; E. Coy; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| Injection of several pure fluids into a chamber with different ambient gases under supercritical temperature but sub- to supercritical condition based on the injectant thermodynamic critical conditions resulted in the following: the jet exhibits classical liquid-like jet second wind-induced type breakup until chamber pressure reaches near the critical point of the jet substance beyond which gas-like visual behavior is observed and no drops are found. For the first time, these ... |
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| Fluid Mechanics and Rheology of Fluid Fiber Flows: Fundamental Science and Technological Applications |
03 JAN 1999 |
7 pages |
| Authors:
Qi Wang; INDIANA UNIV FOUNDATION INDIANAPOLIS RESEARCH AND SPONSORED PROGRAMS
|
| The research activities are focused on modeling of polymeric liquid crystal (LCP) flows. We first summarizes our comprehensive studies on the shear and elongational flow with an imposed velocity field. This includes a complete characterization of the orientational equilibrium and their bifurcation behavior as well as the detailed study on the orientation dynamics with respect to both types of flows. In particular, biaxial patterns and their ... |
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| Fluid Mechanics and Rheology of Fluid Fiber Flow: Fundamental Science and Technological Applications |
03 JAN 1999 |
7 pages |
| Authors:
Qi Wang; INDIANA UNIV FOUNDATION INDIANAPOLIS RESEARCH AND SPONSORED PROGRAMS
|
| The research activities are focused on modeling of polymeric liquid crystal (LCF) flows. We first summarizes our comprehensive studies on the shear and elongational flow with an imposed velocity field. This includes a complete characterization of the orientational equilibria and their bifurcation behavior as well as the detailed study on the orientation dynamics with respect to both types of flows. In particular, biaxial patterns and ... |
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| General Report: Sonochemistry and Sonoluminescence Conference |
01 FEB 98 |
14 pages |
| Authors:
Lawrence A. Crum; UNIV OF WASHINGTON SEATTLE APPLIED PHYSICS LAB
|
| The presentation of data that demonstrate that a sonoluminescing bubble can produce observable sonochemistry was also an important and interesting aspect of the ASI. Since sonochemistry has been difficult to study in the past because of the many bubbles that are typically formed within a cavitation field, the development of a system for studying SBSC is considered an important contribution to the field. An additional topic of much discussion was ... |
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| A Ballistic Compressor-Based Setup for the Visualization of Liquid Propellant Jet Combustion Above 100 MPa |
SEP 97 |
44 pages |
| Authors:
Avi Birk; Douglas E. Kooker; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This report describes the components and operation of an experimental setup for the visualization of liquid propellant (LP) jet combustion at pressures above 100 MPa. The apparatus consists of an in-line ballistic compressor and LP injector. The ballistic compressor, based on a modified 76-mm gun, provides high pressure (55 MPa) clear hot gas for the jet ignition. A piston (projectile) is fired toward a test chamber beyond the barrel's end, ... |
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| ARO and AFOSR Contractors Meeting in Chemical Propulsion, Held in Virginia Beach, Virginia on 3-6 June 1996 |
20 JUN 96 |
299 pages |
| Authors:
David M. Mann; Mitat A. Birkan; Julian M. Tishkoff; AIR FORCE OFFICE OF SCIENTIFIC RESEARCH BOLLING AFB DC
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| Partial contents: Supercritical droplet behavior; Fundamentals of acoustic instabilities in liquid-propellant rockets; Modeling liquid jet atomization proceses; Liquid-propellant droplets dynamics and combustions in supercritical forced convective environments; Contributions of shear coaxial injectors to liquid rocket motor combustion instabilities; High pressure combustion studies under combustion driven oscillatory flow conditions; Droplet collision on liquid propellant combustion; Combustion and plumes; Development of a collisional radiative emission model for strongly nonequilibrium flows; Energy transfer ... |
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| (DURIP94) Aerospace Post-Processing and Visualization Lab |
31 DEC 95 |
23 pages |
| Authors:
Stephen D. Heister; Gregory A. Blaisdell; Thomas N. Farris; Steven P. Schneider; PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS
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| This report summarizes a Defense University Research Investment Program (DURIP) project involving creation of an Aerospace Post-Processing and Visualization Lab (APVL) in the School of Aeronautics and Astronautics at Purdue University. Even though the entire facility has been in place for about eight months, it has had a dramatic impact on the capabilities of our department to visualize complex three dimensional and/or time-dependent data from both experiments and computations. Innovative ... |
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| Modeling Liquid Jet Atomization Processes |
19 NOV 94 |
65 pages |
| Authors:
Stephen D. Heister; PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS
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| This report summarizes efforts in developing an analytic/numerical modeling capability for both steady and unsteady liquid jet atomization processes. The research involves the application of boundary element methods to model nonlinear deformation of liquid surfaces. An inviscid model has been developed to investigate dynamics of a finite-length jet which includes the presence of the orifice flow passages. In addition, a second model has been developed to simulate gas-phase interactions with ... |
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| Combustion Instability Phenomena of Importance to Liquid Propellant Engines |
31 AUG 94 |
80 pages |
| Authors:
Robert J. Santoro; William E. Anderson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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| A systematic study of the atomization of impinging liquid jets was performed. Effects of jet flow condition, orifice diameter, impingement angle, pre-impingement length, fabrication procedure, and jet velocity at steady and oscillating, and atmospheric- and high-pressure ambient conditions were investigated. Measurements of sheet breakup length, drop size and velocity distribution, and the length between sheet structures and detached ligaments were made. Results of the experiments were compared to theoretical predictions. ... |
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| Fundamental Studies of Diamond Growth and Surface Reactions |
JUL 94 |
143 pages |
| Authors:
Alan B. Harker; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| This report summarizes the research carried out during the period March 1991 through May 1994 at Rockwell Science Center under ONR contract No. Nooo14-91-C-0048. This contract was part of the ONR directed effort on the development of polycrystalline diamond as an optical material. A primary focus of the research was investigating the relationships between the microstructure of polycrystalline diamond and its optical and mechanical properties. The program also involved a ... |
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| Liquefied Metal Jet Program Automation and Robotics Research Institute (ARRL) |
03 MAR 94 |
19 pages |
| Authors:
TEXAS INSTRUMENTS INC DALLAS DEFENSE SYSTEMS AND ELECTRONICS GROUP
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| Contents: Introduction; reports and demonstrations, SOW 5.1; Equipment, SOW 5.2; Fluidizer; Droplet generator; Jet/Droplet Stream; Target chamber; System control; System test and experimentation |
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| Combustion Instability Phenomena of Importance to Liquid Propellant Engines |
31 JUL 93 |
23 pages |
| Authors:
Robert J. Santoro; William E. Anderson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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| A study examining impinging liquid jets has been underway to determine physical mechanisms responsible for combustion instabilities in liquid bi-propellant rocket engines. Primary atomization has been identified as an important process. Measurements of atomization length, wave structure, and drop size and velocity distribution were made under various ambient conditions. Test parameters included geometric effects and flow effects. It was observed that pre-impingement jet conditions, specifically whether they were laminar or ... |
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| Mechanism of Intermittent Atomization |
JUN 93 |
94 pages |
| Authors:
S. P. Lin; CLARKSON UNIV POTSDAM NY
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| A theory is developed for the purpose of enhancing the efficiency of internal combustion engines, and to reduce the air pollution caused by inefficient combustion. The theoretical results show that the droplet formation from the leading edge of the liquid fuel jet is caused by th Taylor-Lamb instability during the decerelation phase of the intermittent spray. The mechanism of droplet formation from the rest of the liquid-gas interface is caused ... |
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| An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion |
22 OCT 92 |
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| Authors:
RENSSELAER POLYTECHNIC INST TROY NY
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 | This report period has been primarily concerned with the development of a two-fluid Computation Fluid Dynamics (CFD) model for a free two-phase jet. This model has been implemented into PHOENICS and evaluated on a RISC/6000 work station and the CRAY YMP-8 at Stennis Space Center. We first present a state-of- the-art two-fluid model for air/water flows, which consists of the phasic three- dimensional conservation equations of mass and momentum. The ... |
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| A Study of the Breakup and Atomization of a Combusting Diesel Fuel Spray by Phase Doppler Anemometry, |
23 JUL 1992 |
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| Authors:
G. Pitcher; G. Wigley; TECHNICAL UNIV OF LISBON (PORTUGAL)
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| Fuel droplet velocity and size measurements have been obtained in a combusting Diesel spray inside a single-cylinder direct injection Diesel engine. The measurements were made in the near nozzle region by phase Doppler anemometry with high spatial and temporal resolution. An analysis of the data describes the fuel spray breakup and atomization based on a liquid jet and model and identifies three distinct zones in the developing spray. (Author) |
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| An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion |
31 MAR 92 |
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| Authors:
RENSSELAER POLYTECHNIC INST TROY NY
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| This report period has been concerned with performing an analysis of the air entrainment process associated with a plunging liquid jet. In particular, a linear stability analysis was successfully performed. The salient results of this work are contained in the enclosed draft technical paper entitled: 'The Analysis of af Plunging Liquid Jet - The Air Entrainment Process'. It appears that there has been a misunderstanding on the part of the ... |
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| An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion |
24 DEC 91 |
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| Authors:
F. Bonetto; R. T. Lahey Jr; RENSSELAER POLYTECHNIC INST TROY NY
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| A good understanding of the air carryunder and bubble dispersion process associated with a plunging liquid jet is vital if one is to be able to quantify such diverse phenomena as the environmental impact of power plant discharges, sea surface chemistry, the meteorological significance of (Breaking) ocean waves, the performance of certain type of chemical reactors, the 'greenhouse' effect (ie, the absorption of CO2 by the oceans), and a number ... |
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| An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion |
20 JUN 91 |
10 pages |
| Authors:
RENSSELAER POLYTECHNIC INST TROY NY
|
| During the Second Quarter of this research project preliminary analysis was performed on two-phase jet spreading phenomena. Appropriate equations of motion have been derived by assembling the relevant equations and adding the appropriate term representing the action of surface tension, which was not originally included. These equations were nondimensionalized for a long, narrow jet. The resulting equations are parabolic, so that numerical solution should be straightforward. The equations of motion ... |
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| Jet Breakup and Combustion Modeling for the Regenerative Liquid Propellant Gun |
APR 91 |
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| Authors:
Terence P. Coffee; Paul G. Baer; Walter F. Morrison; Gloria P. Wren; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Although interior ballistic models for the regenerative liquid propellant gun have been shown to be capable of accurately describing the mechanical response of the system, descriptions of the breakup and combustion of the liquid jet have proven less satisfactory. The propellant has been assumed to break into droplets whose diameters are functions of piston position or chamber pressure, and then combust according to a pressure-dependent burn rate law. This empirical ... |
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| Effect of Monomolecular Films on the Underlying Ambient-Noise Field. Part 2. Low Sea State and Laboratory Tests |
FEB 91 |
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| Authors:
J. J. Rohr; R. M. Detsch; NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
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| A series of low sea-state tests show that the reduction of surface- related ambient noise beneath monomolecular (slick-forming) films begins between 1 and 2 kHz and extends to at least 70 kHz. Although the amount of noise reduction varies between experiments, attenuations of up to 8 dB are not uncommon. Most of the experiments are conducted in the absence of whitecapping, where for wind speeds are greater than 2 m/s, ... |
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| One-Dimensional Analysis of a Liquid Jet in a Regenerative Liquid Propellant Gun |
APR 90 |
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| Authors:
Gloria P. Wren; Paul S. Gough; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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| In the regenerative liquid propellant gun (RLPG) a liquid monopropellant is injected by a moving piston in the form of an annular jet from a reservoir into a combustion chamber. Currently there are a number of lumped parameter models of the RLPG in use in the United States. However, the structure and spatial extension of the jet are not considered in any of these models. In this report the details ... |
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| Development of Vapor Dispersion Models for Nonneutrally Buoyant Gas Mixtures-Analysis of TFI/NH3 Test Data |
OCT 88 |
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| Authors:
Thomas O. Spicer; Jerry Havens; ARKANSAS UNIV FAYETTEVILLE DEPT OF CHEMICAL ENGINEERING
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| Field-scale releases of pressurized anhydrous ammonia were performed by the Lawrence Livermore National Laboratories in 1983 for the U.S. Coast Guard, the Fertilizer Institute, and Environment Canada. Release rates for the four experiments ranged between 80 and 130 kilograms per second. The pressurized liquid ammonia jet formed a denser-than-air aerosol cloud. A method of determining the relative importance of jet and nonjet dispersion processes is discussed. The data from these ... |
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| Investigation of the Impact Performance of Various Glass and Ceramic Systems |
31 AUG 88 |
92 pages |
| Authors:
J. E. Field; CAMBRIDGE UNIV (ENGLAND) CAVENDISH LAB
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| This report describes our research on the impact behavior of various glass and ceramic systems. The first section describes the liquid impact technique and experiments in which high velocity liquid jets were fired at specimens over a range of velocities and the post impact (i.e. residual ) strength measured. The jet technique is velocities and the post impact (i.e. residual ) strength measured. The jet technique is a convenient method ... |
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| Spray Formation: Three-Dimensional Liquid Break-Up due to Surface Tension |
09 AUG 88 |
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| Authors:
Robert E. Childs; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
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| The growth instabilities on the interface between a liquid jet and its gaseous environment is an important mechanism in spray atomization, and it is the subject of the work reported herein. Numerical simulations based on the Navier-Stokes equations were used to model liquid/gas interface flows. An algorithm was developed for solving the unsteady Navier-Stokes equations for incompressible fluid with a discontinuity in density and with surface tensions and its accuracy ... |
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| Survey of the Literature: Controlled Generation of Liquid Droplets |
AUG 88 |
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| Authors:
Craig R. Allan; Hugh R. Carlon; Arthur K. Stuempfle; Thomas E. Hoffer; Richard L. Pitter; CHEMICAL RESEARCH DEVELOPMENT AND ENGINEERING CENTER ABERDEEN PROVING GROUND MD
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| Techniques utilized in generating large drops from visco-elastic liquids, which are also referred to as non-Newtonian liquids, are surveyed, reviewed and evaluated. The minimum droplet size of interest was 0.2 mm (200 micrometers). Drop generation techniques considered include the capillary dropper, liquid jets, atomization, the spinning disc, vaporization-condensation, impulse generation, and other techniques. Of these, only three generator configurations were found to meet experimental requirements. These included a drop impulse/ejection ... |
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| Regenerative Electrical Igniter for a Liquid Propellant Gun |
AUG 87 |
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| Authors:
Avi Birk; Phil Reeves; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A novel igniter for a regenerative liquid propellant gun (RLPG) is described, which utilizes only the liquid gun propellant (LGP). The liquid which is sealed in the igniter is ignited by an arc discharge causing a rise in pressure. At a predetermined pressure the igniter opens and gas products and unreacted liquid are injected to mix and react externally. The liquid jet derives it injection pressure hydraulically from the constantly ... |
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| Droplet Formation for Liquid Monopropellant Jets |
AUG 87 |
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| Authors:
Nelson A. Macken; BATTELLE COLUMBUS LABS RESEARCH TRIANGLE PARK NC
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| The hydrodynamic development of droplets for conditions approximating those in the combustion chamber of regenerative liquid propellant guns has been investigated. The report contains a literature survey and discussion of various breakup mechanisms. Aerodynamic interaction is analyzed using classical stability theory and a formulation applied to anticipated working conditions. The model predicts mass removed and droplet size as a function of time. Results indicate that the jet does break up ... |
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| Regenerative Electrical Igniter for a Liquid Propellant Gun |
AUG 87 |
|
| Authors:
Avi Birk; Phil Reeves; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A novel igniter for a regenerative liquid propellant gun (RLPG) is described, which utilizes only the liquid gun propellant (LGP). The liquid which is sealed in the igniter is ignited by an arc discharge causing a rise in pressure. At a predetermined pressure the igniter opens and gas products and unreacted liquid are injected to mix and react externally. The liquid jet derives its injection pressure hydraulically from the constantly ... |
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| Rheology of Dissemination |
OCT 86 |
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| Authors:
E. A. Kearsley; RHEOLOGY RESEARCH GAITHERSBURG MD
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| The breakup of a cylindrical jet of BKZ fluid perturbed sinusoidally is modeled in one dimension. Surfaced tension, nonlinear viscoelastic forces and both radial and axial acceleration are taken into account. The model leads to an intgro-differential equation. A FORTRAN program is developed to solve this equation using a predictor corrector method. Various subroutines are given to evaluate necessary derivatives with finite differences and to solve a pentadiagonal matrix which ... |
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| Dense-Spray Structure and Phenomena |
15 AUG 86 |
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| Authors:
R. N. Parthasarathy; A. Sagar; G. M. Faeth; MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING
|
| This report describes theoretical and experimental study of dense sprays. The work was divided into two phases: (1) an investigation of particle laden water jets; and (2) an investigation of large scale liquid jet in the atomization regime. The particle laden jet experiments involved nearly monodisperse glass particles in water injected into still water, to simulate phase density ratios typical of high pressure sprays. Preliminary findings suggest that the locally ... |
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| Impingement of Liquid Fuel Sprays on Heated Walls |
12 FEB 86 |
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| Authors:
Norman Chigier; Francisco Ruiz; James Zurlo; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MECHANICAL ENGINEERING
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| An experimental study was made of the structure of high speed Diesel jets. A constant volume chamber was constructed into which sprays of different liquids at a controlled pressure and duration can be injected. The chamber can be pressurized to a design pressure of 900 psi and heated to 750 F. An air operated pump provides liquid injection pressures up to 10,000 psi. Microphotographs of the spray showed the formation ... |
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| Effects of Airblast Atomizer Design Upon Spray Quality, |
1984 |
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| Authors:
A. K. Jasuja; CRANFIELD INST OF TECH (ENGLAND) SCHOOL OF MECHANICAL ENGINEERING
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| This paper reviews the results of numerous investigations that have been conducted on airblast atomization as applied to gas turbine engines. The primary motivation for this is the need to identify the effect that various design features have upon the spray quality so that atomizers of optimum performance can be designed with a minimum of cost and complexity. Attention is focused upon such factors as the atomizer scale, configuration, the ... |
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