Bulletin of the American Physical Society
2005 14th APS Topical Conference on Shock Compression of Condensed Matter
Sunday–Friday, July 31–August 5 2005; Baltimore, MD
Session C2: Detonations & Shock-Induced Chemistry I |
Hide Abstracts |
Chair: Raafat Guirguis, Naval Surface Warfare Center, Indian Head Room: Hyatt Regency Constellation C |
Monday, August 1, 2005 11:00AM - 11:15AM |
C2.00001: Study of Detonation and Cylinder Velocities for Aluminized Explosives Leonard Stiel, Ernest Baker, Christos Capellos The detonation properties of aluminized explosives have been studied using experimental data available in the literature and EXP-6 thermo-chemical potential calculations with the JAGUAR computer program. It has been found that the observed detonation velocity behavior for aluminized explosives can be accurately represented by a reaction zone model in which unreacted aluminum is initially in equilibrium with H-C-N-O compounds. The JAGUAR procedures have been modified to represent the aluminum reaction zone behavior and to enable specified temperature differences between the gas and aluminum particles in the initial portion of this reaction zone. The modified procedures enable isentropic expansion for incomplete or complete aluminum reaction in the zone, and result in close agreement with experimental cylinder test data for several explosives. In order to aid in the application of the model, constants of thermodynamic equations of state are related to the extent of aluminum reaction. [Preview Abstract] |
Monday, August 1, 2005 11:15AM - 11:30AM |
C2.00002: Critical Conditions for Ignition of Aluminum Particles in Cylindrical Explosive Charges David Frost, Samuel Goroshin, Jeffrey Levine, Fan Zhang The critical conditions for the ignition of spherical aluminum particles dispersed during the detonation of long cylindrical explosive charges have been investigated experimentally. The charges consist of packed beds of aluminum particles (Valimet, CA), ranging in size from 3 -– 115 $\mu$m in diameter, and saturated with sensitized liquid nitromethane. The ignition conditions depend on both the charge and particle diameters, which govern the thermal history of the particles as they are dispersed within the conically expanding products. For a given charge diameter, the most reactive particles correspond to an intermediate size ($\sim$55 $\mu$m dia). For this particle size, with increasing charge diameter the particle reaction behavior progresses through several distinct regimes: i) no particle reaction, ii) reaction at isolated spots, iii) reaction in distinct radial bands, and iv) continuous reaction of the particle cloud. In each case, a separation between the detonation front and the onset of aluminum reaction is always observed. To determine the point of particle ignition, visible radiation from the charge is recorded, through a slit, with a 3-color pyrometer and with a line spectrometer, with the wavelengths chosen to overlap the AlO emission lines. [Preview Abstract] |
Monday, August 1, 2005 11:30AM - 11:45AM |
C2.00003: Prompt Reaction of Aluminum in Detonating Explosives Harold Sandusky, Richard Granholm The potential of aluminum reaction to boost detonation energy has been studied for decades, most recently spurred by the availability of nanometer-sized particles. A review of the literature provides perspective for a recent study with the small-scale shock reactivity test. In this test, $<$1/2-g samples in confinement are shock loaded on one end, and the output at the other end dents a soft witness block. One test series had 0.3 g of HMX mixed with various forms of aluminum added in amounts of up to 25{\%} of the total sample mass, with the deepest dent for H-5 aluminum occuring at 15{\%}. Test results on ammonium perchlorate mixed with H-5 aluminum were consistent with the peak in detonation velocity reported in \textit{Combustion and Flame} by Price in 1973 on similar mixtures. One outcome of this study is a new interpretation for the participation of aluminum in large scale gap tests on plastic-bonded explosives, which was discussed by Bernecker at this meeting in 1987. [Preview Abstract] |
Monday, August 1, 2005 11:45AM - 12:00PM |
C2.00004: Atmospheric Effects on the Combustion of Detonating Aluminized Explosives Joel Carney, Scott Miller, Jared Gump, Gerry Pangilinan The detonation and subsequent combustion of aluminized explosive formulations depend heavily on the reactions of aluminum and oxygen. Fuel-rich formulations require oxygen from an external source (nominally an oxygen-containing atmosphere) to burn the fuel to completion. Dynamic spectroscopic measurements were made for two different aluminized explosives (PBXIH-135 and PBXN-111) to investigate the effect of changing atmospheres on the combustion properties of aluminum. Both explosive formulations were tested under normal atmospheric conditions and in an atmosphere of nitrogen. Light emission (from 350-550 nm) from the explosive events was collected in a spectrometer and dispersed temporally in a streak camera. New, nitrogen-containing species (near 387 and 416 nm) arise in the nitrogen atmosphere experiments for both formulations that seem to replace aluminum monoxide as a primary intermediate product for the fuel. The peak assignments and global kinetics of each species will be presented and the implications of these results on atmospheric effects will be discussed. [Preview Abstract] |
Monday, August 1, 2005 12:00PM - 12:15PM |
C2.00005: Model of Non-premixed Combustion of Aluminium---Air Mixtures Boris Khasainov, Allen Kuhl, Sergey Victorov, Peter Neuwald For solving the problem of shock-induced dissemination and burning of aluminium particles in air, we have developed a new solver based on equilibrium equation of states (EOS) of 2-phase reactive mixtures. The solver uses two pre-calculated tables; the larger one describes the equilibrium states of reaction products and the smaller one describes states of fresh air. Being linked with gas-dynamics equations, the solver finds iteratively the mixture pressure and temperature; in addition it furnishes a complete description of chemical and physical transformations. 2D numerical simulations give encouraging agreement with experimental pressure histories recorded on the chamber wall. It is shown that multiple blast wave reflections from the walls of the chamber strongly accelerate particle burning. The results demonstrate the advantages of the equilibrium EOS model and appeal for 3D AMR calculations on massively-parallel computers, which should better define the initial stage of turbulent particle dissemination. [Preview Abstract] |
Monday, August 1, 2005 12:15PM - 12:30PM |
C2.00006: Reaction Zone Structure of High Explosives With Additions Alexander Utkin, Alexander Ananin, Sergey Pershin The reaction zone structure for steady-state detonation waves in pressed HE with additions TNT/RDX 25/75+25{\%} graphite like boron nitride BN and RDX+16.5{\%} graphite have been investigated. The interest in these mixtures was caused by unusual particle velocity profile, recorded by electromagnetic method elsewhere: sharp velocity decrease was observed behind shock front. To investigate that problem in detail the laser interferometric system VISAR was used. The laser beam was reflected from aluminum foil with a thickness from 50 to 850 mkm which was placed on the boundary between HE charge and water window. As a result of experiments the reaction time was found (150-200 ns) and it was demonstrated that the ratio of particle velocity in Von Neumann spike to Chapman-Jouguet velocity can exceed 2. No peculiarities on the particle velocity profiles were found. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700