| Effects of Corona, Spark and Surface Discharges on Ignition Delay and Deflagration-to-Detonation Times in Pulsed Detonation Engines (Postprint) |
DEC 2006 |
12 pages |
| Authors:
Kenneth Busby; Jennifer Corrigan; Sheng-Tao Yu; Skip Williams; Campbell Carter; Frederick Schauer; John Hoke; Charles Cathey; Martin Gundersen; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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 | The purpose of the research described herein is to compare the ignition delays in an experimental pulsed detonation engine produced by thermal and non-thermal ignitions. The commercial thermal ignition has a pulse duration of about 1 microsec, whereas the non-thermal ignitions have pulse durations of 100 nanosec. Ignition delay is an important factor, along with fill and purge times, that limit the maximum repetition rate and thrust of pulsed detonation ... |
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| Investigation of Kinetics of Iso-Octane Ignition Under Scramjet Conditions (Postprint) |
OCT 2006 |
10 pages |
| Authors:
Moshan S. Kahandawala; Shehan A. Corera; Sukh S. Sidhu; Skip Williams; Campbell D. Carter; DAYTON UNIV OH DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| A single pulse reflected shock tube was used to investigate iso-octane ignition over the temperature range of 900-1400 K at a pressure of ~1 atm. To account for the anticipated long ignition delay times at the lower temperatures, long shock tube dwell times (~12 ms) at lower temperature and near atmospheric pressure were achieved by using argon-helium mix as a driver gas. Chemical thermometer experiments were conducted to remove any ... |
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| Diode Laser Diagnostics of High Speed Flows (Postprint) |
OCT 2006 |
17 pages |
| Authors:
Skip Williams; Dominic Barone; Todd Barhorst; Kevin Jackson; K. C. Lin; Pat Masterson; Qingchun Zhao; Andrew D. Sappey; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| This document contains the specific requirements and preliminary results for the Optical Mass Capture (OMC) experiment for the Fundamental RESearch Hypersonic Flight experimentation (FRESH Fx) program. The objective of this effort is to develop and demonstrate in flight a diode-laser-based measurement of engine air mass capture in the inlet or isolator of a hypersonic vehicle over an altitude range of 60,000-90,000 ft with an average Mach number of 7.5 over ... |
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| Passive Optical Diagnostic of Xe-Propelled Hall Thrusters. I. Emission Cross Sections (Reprint) |
09 JUN 2006 |
12 pages |
| Authors:
Yu-Hui Chiu; Brad L. Austin; Skip Williams; Rainer A. Dressier; George F. Karabadzhak; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| This paper presents a set of xenon apparent emission excitation cross sections for emission lines that have diagnostic value in the analysis of Xe-propelled Hall thruster plasmas. Emission cross sections are presented for three excitation processes involving ground-state xenon atoms: e^- + Xe, Xe^+ + Xe, and Xe^2+ + Xe. The cross sections are derived from luminescence spectra produced at single-collision conditions. Apparent emission excitation cross sections are tabulated for ... |
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| A Microwave-Augmented Plasma Torch Module |
MAR 2006 |
12 pages |
| Authors:
S. P. Kuo; Daniel Bivolaru; Skip Williams; Campbell D. Carter; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| A new plasma torch device which combines arc and microwave discharges to enhance the size and enthalpy of the plasma torch is described. A cylindrical-shaped plasma torch module is integrated into a tapered rectangular cavity to form a microwave adaptor at one end, which couples the microwave power injected into the cavity from the other end to the arc plasma generated by the torch module. A theoretical study of the ... |
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| Investigation of Kinetics of Iso-Octane Ignition Under Scramjet Conditions |
OCT 2005 |
10 pages |
| Authors:
Moshan S. Kahandawala; Shehan A. Corera; Skip Williams; Campbell D. Carter; Sukh S. Sidhul; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| A single pulse reflected shock tube was used to investigate iso-octane ignition over the temperature range of 900-1400 K at a pressure of 1 atm. To account for the anticipated long ignition delay times at the lower temperatures, long shock tube dwell times (12 ms) at lower temperature and near atmospheric pressure were achieved by using argon-helium mix as a driver gas. Chemical thermometer experiments were conducted to remove any ... |
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| Ion-Molecule Rate Constants and Branching Ratios for the Reaction of N(3)+ + O(2) From 120 to 1400 K |
15 NOV 2004 |
9 pages |
| Authors:
Svetozar Popovic; Anthony J. Midey; Skip Williams; Abel I. Fernandez; A. A. Viggiano; Peng Zhang; K. Morokuma; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| The kinetics of the reaction of N3(+) with O2 has been studied from 120 to 1400 K using both a selected ion flow tube and high-temperature flowing afterglow. The rate constant decreases from 120 K to approx. 1200 K and then increases slightly up to the maximum temperature studied, 1400 K. The rate constant compares well to most of the previous measurements in the overlapping temperature range. Comparing the results ... |
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| Quantitative Detection of Singlet O2 by Cavity-Enhanced Absorption |
15 MAY 2004 |
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| Authors:
Skip Williams; Manish Gupta; Thomas Owano; Douglas S. Baer; Anthony O'Keefe; David R. Yarkony; Spiridoula Matsika; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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 | A method for the practical determination of the absolute concentration of single oxygen is discussed. The method is based on sensitive off-axis integrated-cavity-output spectroscopy (ICOS). Off-axis ICOS allows narrowband, continuous-wave lasers to be used in conjunction with optical cavities to record sensitive absorption measurements. The details of the method, as well as spectroscopic data confirming the first observation of the (1,0) band of the Noxon system are presented. The absolute ... |
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| Quantitative Determination of Singlet Oxygen Density and Temperature for Oxygen-Iodine Laser Applications |
2004 |
6 pages |
| Authors:
Manish Gupta; Thomas Owano; Douglas S. Baer; Anthony O'Keefe; Skip Williams; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| Guided-Ion Beam Measurements of X(+)+NO (X=Ar, Nsub2) Reactions. |
15 MAY 1994 |
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| Authors:
Susan T. Graul; Skip Williams; Rainer A. Dressler; Richard H. Salter; Edmond Murad; PHILLIPS LAB HANSCOM AFB MA
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| Cross section and product ion time-of-flight measurements are presented for the X(+)+NO (X=Ar, Nsub2) collision systems over a collision energy range of 0.1-20 eV (c.m.). The experiments are carried out in an octopole guided-ion beam apparatus. Charge transfer is the main channel observed and dissociative charge-transfer products are observed for collision energies equal to or greater than their respective thermodynamic thresholds. A weak channel leading to ArN(+) and/or ArO(+) is ... |
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| Guided-Ion Beam Measurements of the Kr(+) + NO Charge-Transfer Reaction |
17 DEC 1993 |
9 pages |
| Authors:
Rainer A. Dressler; Skip Williams; Susan T. Graul; Richard H. Salter; Edmond Murad; PHILLIPS LAB HANSCOM AFB MA
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| Guided-ion beam measurements of Kr(+) + NO charge-transfer reaction cross sections are presented over a collision energy range of 0.08 to 16 eV (c. m.). At energies below 2 eV, the charge-transfer cross section is approximately two orders of magnitude smaller than the Langevin capture cross section and decreases with collision energy displaying an EsubT(-0.4) dependence. The cross section reaches a minimum at about 3 eV, increases with collision energy ... |
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