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Electrothermal analysis as a tool for Designing Electric Detonator Firing Circuits
Author(s) -
Austing J. L.,
Tulis A. J.,
Schmitt H. R.,
Urbanski E.,
Mosora J. A.,
Hawley J.
Publication year - 1984
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19840090604
Subject(s) - detonator , capacitor , electronic circuit , materials science , electrolytic capacitor , mechanics , nuclear engineering , internal resistance , explosive material , electrical engineering , voltage , thermodynamics , engineering , chemistry , physics , battery (electricity) , power (physics) , organic chemistry
The use of modified forms of the Rosenthal electrothermal equation to aid in the design of a capacitor discharge firing circuit for a specific detonator is described. The electrothermal parameters C p and γ, representing the heat capacity of the bridge and the heat loss factor, respectively, were calculated from previously obtained firing data for the detonator. These calculations provided input to the design of a firing circuit utilizing electrolytic capacitors, which have a large value of electrical capacity but also a non‐negligible internal resistance. Calculations were performed which (1) revealed the degrading effect on detonator initiation caused by too large a value of internal resistance, and (2) permitted selection of a particular capacitor that would allow reliable functioning of the detonator with initiation times of about 230 μs. The circuit was designed utilizing this capacitor, and in the experimental evaluation of the circuit the measured initiation times were compared with the calculated values. Good agreement between the two was documented, and the conclusion was reached that the detonator functioned reliably. The merits of the electrothermal analysis and the assumptions utilized therein relative to a vigorous heat transfer/reaction kinetics modeling of the flow of energy from the bridge into the explosive flash charge are discussed in detail.