No abstract

Vergleich der Zylindertest-Daten mit den Rechen-Codes für homogene Explosivstoffe Daten aus dem Kupferzy lindertest von homogenen Explosivstoffen wurden gesammelt und vergli chen mit de n Relativ-Volumina nahe 2, 4 und 7 . Die Detonation senerg ie n, proportional zum Quadrat der Zy linderwand geschwindi gke it, wurden bezogen auf hochverdichtetes PETN. Diese Energien werden verg lichen mit JWL-Werten, die abgeleitet wurden aus dem Hydrocode und aus den drei Codes für das Chemi sc he G le ichgewicht: Ti ge r BKWR, Ti ger JCZ3 und CHEQ. Die Werte des ßKWR sind durchweg hoch, können aber korrigiert werden durch Eichun g mit PETN. JCZ3 li efert die besten allumfassende n Energ iewerte der 3 Modell e, obwo hl diese durchweg hoch sind bei v = 2. Die gesamte Detonationsenerg ie beim JWL-Code liegt nahe der gemessenen Werte. All es in all em ist di e Qualität beim Fitten der the rmoellemi sc hen Codes auf di e aus den Zylinderwerten abge leiteten Detonationsenergien schl echt und e in renorm ali sie rter Code is dringend notwendi g. SummaryCopper cy linde r data for homogeneous explosiv es are assemb led and compared for relative vo lumes of approxi mately 2, 4 and 7. The detonation energ ies, proportional to cylinde r wa ll velociries-sq uared, are referenced to hi gh-density PETN. These ene rg ies are compared for JWL 's derived from hyd rocodes and from the three chemi cal-equ ilibrium codes: Ti ger BKWR, Ti ger JCZ3 and CHEQ . BKWR is consistently hi gh but ca n be corrected by adjustm ent with PETN. JCZ3 provides the best overall energies of the three models, although it is consistently hi gh at v = 2. The total e nergy of detonation in the JWL is shown [0 be e10se to the meas ured va lues. Ove rall , the quality of fit of the the rmochemical codes to the cy linder-derived detonation energies is poor and a renorm ali zed code is badly needed.

Fabry-Perot laser interferometry is used to obtain nanosecond time resolved particle velocity histories of the free surfaces of copper, tantalum, or magnesium disks driven by detonating triaminotrinitrobenzene ͑TATB͒-based charges and of the interfaces between detonating TATB and transparent salt crystals. Detonation reaction zone profiles are measured for self-sustaining detonation waves propagating through various thicknesses of LX-17 ͑92.5% TATB and 7.5% KelF binder͒ and pure ultrafine particle size TATB. The experimental records are compared to particle velocity histories calculated with the DYNA2D hydrodynamic code using the ignition and growth reactive flow model. The calculations yield excellent agreement with the experimental records for LX-17 using an unreacted von Neumann spike pressure of 33.7 GPa, a reaction rate law which releases 70% of the chemical energy within 100 ns, and the remaining 30% over 300 additional ns, and a reaction product equation of state fit to cylinder test and supracompression data with a Chapman-Jouguet ͑C-J͒ pressure of 25 GPa. The late time energy release is attributed to diffusion controlled solid carbon particle formation. Ultrafine TATB, pressed to a lower density (1.80 g/cm 3 ) than LX-17 (1.905 g/cm 3 ), exhibits lower unreacted spike and C-J pressures than LX-17 but similar reaction rates.

Fabry–Perot laser interferometry was used to obtain nanosecond time resolved particle velocity histories of the free surfaces of tantalum discs accelerated by detonating pentaerythritol tetranitrate (PETN) charges and of the interfaces between PETN detonation products and lithium fluoride crystals. The experimental records were compared to particle velocity histories calculated using very finely zoned meshes of the exact dimensions with the DYNA2D hydrodynamic code. The duration of the PETN detonation reaction zone was demonstrated to be less than the 5 ns initial resolution of the Fabry–Perot technique, because the experimental records were accurately calculated using an instantaneous chemical reaction, the Chapman–Jouguet (C-J) model of detonation, and the reaction product Jones–Wilkins–Lee (JWL) equation of state for PETN detonation products previously determined by supracompression (overdriven detonation) studies. Some of the PETN charges were pressed to densities approaching the crystal density and exhibited the phenomenon of superdetonation. An ignition and growth Zeldovich–von Neumann–Doring (ZND) reactive flow model was developed to explain these experimental records and the results of previous PETN shock initiation experiments on single crystals of PETN. Good agreement was obtained for the induction time delays preceding chemical reaction, the run distances at which the initial shock waves were overtaken by the detonation waves in the compressed PETN, and the measured particle velocity histories produced by the overdriven detonation waves before they could relax to steady state C-J velocity and pressure.

No abstract