Numerical simulation of the ignition law for a hot bridge wire electroexplosive device

Abstract

Hot bridge wire electroexplosive devices (EEDs) are widely used as starting elements in aerospace and other fields. Their thermal ignition process and safety testing technology have always been a focus of research. In this paper, we construct a temperature rise model for a hot bridge wire EED by using the law of conservation of energy, and the temperature response of the bridge wire and the reagent is obtained. According to the theoretical and numerical analysis, the sensitive criterion for a hot bridge wire EED is given, and the simulation process for the critical ignition current is designed. Based on this process, the law of the influence of the bridge wire and reagent parameters on the ignition of a hot bridge wire EED was studied. The research results show that a first derivative of the reagent temperature with respect to the radial distance of greater than zero is a sensitive criterion for the ignition of a hot bridge wire EED with high accuracy. Compared with traditional numerical methods, the proposed process makes the acquisition of the critical ignition current more precise and programmable due to the use of sensitive criteria. In addition, the following significant features are noted: the critical ignition current first increases as the square root of the bridge wire radius and then linearly; the square of the critical ignition current increases linearly with the activation energy of the reagent; there is rapid exponential decay of the critical ignition current with increasing reagent combustion heat; asymptotic values are present. In engineering use, it is possible to conveniently design the ignition characteristics of a hot bridge wire EED by changing the radius of the bridge wire. This study serves as a foundational work for the safety testing of hot bridge wire EEDs and can provide theoretical guidance for the safety testing, actual production and use of hot bridge wire EEDs.