PETN spark-gap detonators

Journal Article · 18 May 2020 · Journal of Energetic Materials

DOI: https://doi.org/10.1080/07370652.2020.1756986 · OSTI ID:1619218

Chen, Kenneth C. ^[1]; Warne, Larry K. ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

The well-developed theory of Lorentz plasma that is dominated by electron–ion interactions is used to calculate the PETN arc characteristics. The spark-gap discharge current is a ramp with 10 to 25 ns rise time to peak and remaining constant subsequently. The approximate formulas for the arc channel conductivity, arc temperature, arc radius, and shock pressure from the arc are obtained from a system of nonlinear ordinary differential equations, which is the similarity solution of hydrodynamic equations similar to the Braginskii approximation. These arc parameters are given for the peak current ranging from 100 A to 1000 A and with different rise times. Representative cases are compared to the nonlinear ordinary differential equation code results. The shock pressures at the peak current are comparable to those from a typical commercial EBW bridgewire burst reported in the literature; the arc radius at the peak current is comparable to a typical bridgewire diameter of 0.0375 mm (e.g., RISI detonators, RP-1, and RP-80). The relevant Pop-Plot for low-density PETN is converted into an empirical detonation criterion, which is applicable to explosives subject to shocks of variable pressure. Finally, this criterion is then used to determine the detonation thresholds, which are comparable with test data obtained by Tucker, et al.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Security
• Grant/Contract Number: AC04-94AL85000; NA0003525
• OSTI ID: 1619218
• Report Number(s): SAND-2020-1371J; 683624
• Journal Information: Journal of Energetic Materials, Vol. 39, Issue 1; ISSN 0737-0652
• Publisher: Taylor & FrancisCopyright Statement
• Country of Publication: United States
• Language: English