Comparison of numerical models of a pyrotechnic device

Conference · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5078116

Pierce, K G

The predictions of two numerical models of a hot-wire initiated pyrotechnic device are compared to each other and to experimental results. Both models employ finite difference approximations to the heat diffusion equation in cylindrical coordinates. The temperature dependence of the thermal properties of the pyrotechnic materials and of the bridgewire are modeled. An Arrhenius' model is used to describe the exothermic reaction in the powder. One model employs a single radial coordinate and predicts the radial temperature distribution in the bridgewire and surrounding powder mass. In addition to the radial coordinate, the other model also employs a longitudinal coordinate to predict the temperature distribution parallel to the axis of the bridgewire. The predictions of the two-dimensional model concerning the energy requirements for ignition and the energy losses from the ends of the bridgewire are presented. A comparison of the predictions of the two models and the development of thermal gradients are employed to define the regime where the assumption, in the one-dimensional model, of negligible heat transfer axial to the bridgewire does not lead to significant error. The general problems associated with predicting ignition from a diffusion model are also discussed.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA). Components and Systems Reliability Div.
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5078116
• Report Number(s): SAND-86-1459C; CONF-861230-4; ON: DE86016119
• Resource Relation: Conference: 13. symposium on explosives and pyrotechnics, Hilton Head Island, SC, USA, 2 Dec 1986; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
PYROTECHNIC DEVICES
IGNITION
MATHEMATICAL MODELS
COMPARATIVE EVALUATIONS
FINITE DIFFERENCE METHOD
HEAT TRANSFER
ENERGY TRANSFER
ITERATIVE METHODS
NUMERICAL SOLUTION
420200* - Engineering- Facilities
Equipment
& Techniques
450100 - Military Technology
Weaponry
& National Defense- Chemical Explosions & Explosives