Predicting the Gurney velocity of chemical high explosives: thermochemical code calculations and studies on the detonation products isentrope

ABSTRACT

The simplicity and versatility of the Gurney model has led to its widespread adoption for the calculation of peak fragment velocity of explosively-driven munitions such as fragmentation warheads and artillery projectiles. The Chemical Equilibrium with Applications (CEA) thermochemical code provides several relevant parameters that were found to be important for the construction of a mathematical model for estimating the Gurney velocity of pure and mixed chemical high explosives. Compared to other methods, the proposed model demonstrated its accuracy in predicting the Gurney velocity of sensitive and insensitive explosive compositions. Models based on detonation velocity were found to be particularly inadequate to predict the Gurney velocity of insensitive explosives, which is strong proof that the detonation velocity does not necessarily correlate with the Gurney velocity for all types of high explosives. Results from the cylinder expansion test provide some evidence that the low to moderate metal acceleration ability of insensitive explosives is due to their unique and steep expansion isentropes rather than charge diameter effects or non-ideal detonation behavior.

Graphical abstract

KEYWORDS:

• Gurney velocity
• CEA code
• sensitive explosives
• insensitive explosives
• expansion isentrope

List Of Chemical And Atomic Compositions Of Explosive Compounds/Formulations

ADNT: Ammonium 3,5-dinitro-1,2,4-triazolate (C₂H₄N₆O₄)

AFX-521: 95/5 PYX/Kel-F 800 (C_2.696H_1.095N_1.682O_2.446F_0.133Cl_0.036)

AFX-902: 95/5 NQ/Viton-A

(C_1.047H_3.747N_3.654O_1.827F_0.174)

BTF: Benzotrifuroxan (C₆N₆O₆)

CL-14/Viton-A (97/3): C_2.354H_1.572N_2.273O_2.273F_0.104

Composition C-3: 77/4/10/5/1/3 RDX/TNT/Dinitrotoluene/Mononitrotoluene/Nitrocellulose/Tetryl (C_1.90H_2.83N_2.34O_2.60)

Composition C-4: 91/5.3/2.1/1.6 RDX/Di(2-ethylhexyl) sebacate/Polyisobutylene/Motor oil

(C_1.82H_3.54N_2.46O_2.51)

Composition A-3: 91/9 RDX/Wax (C_1.87H_3.74N_2.46O_2.46)

Composition-B: 63/36/1 RDX/TNT/Wax (C_2.03H_2.64N_2.18O_2.67)

Cyclotol 75/25: RDX/TNT (C_1.78H_2.58N_2.36O_2.69)

Cyclotol 77/23: RDX/TNT (C_1.750H_2.588N_2.385O_2.689)

DAAF: 3,3ʹ-Diamino-4,4ʹ-Azoxyfurazan (C₄H₄N₈O₃)

DNAN/RDX/NTO (40/20/40): C_2.300H_2.368N_2.175O_2.474

FOX-7: 1,1-Diamino-2,2-dinitroethylene (C₂H₄N₄O₄)

(FOX-7)vit: 94/6 FOX-7/Viton-A (C_1.431H_2.653N_2.541O_2.541F_0.208)

(FOX-HMX)vit: 94/6 FOX-HMX/Viton-A

(C_1.431H_2.653N_2.541O_2.541F_0.208)

HMX: 1,3,5,7-Tetranitro-1,3,5,7-tetraazacyclooctane (C₄H₈N₈O₈)

HNS: 2,2ʹ,4,4ʹ,6,6ʹ-Hexanitrostilbene (C₁₄H₆N₆O₁₂)

KH 30: 66.5/30/3.5 HMX/NTO/Viton-A (C_1.454H_2.324N_2.720O_2.490F_0.122)

KH 50: 47.5/50/2.5 HMX/NTO/Viton-A (C_1.478H_2.100N_2.822O_2.438F_0.087)

LX-09: 93/4.6/2.4 HMX/DNPA/FEFO (C_1.43H_2.74N_2.59O_2.72F_0.02)

LX-10: 95/5 HMX/Viton-A (C_1.41H_2.66N_2.57O_2.57F_0.16)

LX-14: 95.5/4.5 HMX/Estane 5702-F1 (C_1.52H_2.92N_2.59O_2.66)

LX-17: 92.5/7.5 TATB/Kel-F 800

(C_2.29H_2.18N_2.15O_2.15F_0.2Cl_0.054)

NM: Nitromethane (CH₃NO₂)

NTO: 3-Nitro-1,2,4-triazol-5-one (C₂H₂N₄O₃)

NTO/DAAF/Kel-F 800 (67/30/3):

(C_1.654H_1.611N_3.193O_1.970F_0.080Cl_0.022)

NTO/FOX-7/Kel-F 800 (67/30/3):

C_1.494H_1.856N_2.872O_2.357F_0.08Cl_0.022

Octol 75/25: HMX/TNT (C_1.78H_2.58N_2.36O_2.69)

Octol 78/22: HMX/TNT (C_1.732H_2.593N_2.399O_2.690)

PBX-91C: 90/10 HMX/HTPB (C_1.924H_3.497N_2.439O_2.455)

PBX-9501: 95/2.5/2.5 HMX/Estane/BDNPA-F (C_1.47H_2.86N_2.60O_2.69)

PBX-9502: 95/5 TATB/Kel-F 800

(C_2.304H_2.232N_2.208O_2.208F_0.133Cl_0.036)

PETN: Pentaerythritol tetranitrate (C₅H₈N₄O₁₂)

RDX:1,3,5-Trinitro-1,3,5-triazacyclohexane (C₃H₆N₆O₆)

RDX/TNT 50/50: C_2.218H_2.453N_2.012O_2.673

RDX/Wax (94/6): C_1.70H_3.39N_2.54O_2.54

RX-36-AH: 51.3/43.7/5.0 HMX/BTF/Viton-A

(C_1.867H_1.480N_2.427O_2.427F_0.174)

RX-43-AC: 95/5 HNX/DER-332 (C_2.313H_1.605N_3.257O_1.562)

RX-45-AA: 95/5 ANTA/Kel-F 800

(C_1.569H_2.232N_3.680O_1.472F_0.133Cl_0.036)

RX-47-AA: 92.514/7.486 CL-14/Kel-F 800

(C_2.313H_1.482N_2.168O_2.168F_0.199Cl_0.054)

RX-48-AA: 92.37/7.63 ADNBF/Kel-F 800

(C_2.446H_1.186N_1.915O_2.299F_0.203Cl_0.055)

TATB: 1,3,5-Triamino-2,4,6-trinitrobenzene (C₆H₆N₆O₆)

Tetryl: 2,4,6-Trinitrophenyl-N-methylnitramine (C₇H₅N₅O₈)

TNAZ: 1,3,3-Trinitroazetidine (C₃H₄N₄O₆)

TNGU: 1,3,4,6- Tetranitroglycoluril (C₄H₂N₈O₁₀)

TNT: 2,4,6-Trinitrotoluene (C₇H₅N₃O₆)

TNT/RDX/NTO (40/20/40): C_2.119H_2.037N_2.300O_2.521

X-0432: 57/43 DINGU/TNT (C_2.308H_1.929N_2.042O_2.610)

X-0535: 95/5 LAX-112/Oxy-461

(C_1.438H_2.746N_3.958O_1.319F_0.071Cl_0.06)