Small-scale pyrotechnic igniter output has been characterized using a high-speed schlieren imaging system for observing critical features of the post-combustion flow. The diagnostic, with laser illumination, was successfully applied towards the quantitative characterization of the output from Ti/KClO4
A pyrotechnic hotwire igniter is an electro-explosive device (EED) that converts input electrical energy to mechanical pressure–volume work via an explosion [1]. The pyrotechnic material is thermally initiated through contact with a metal bridgewire that is heated with approximately 30 mJ of energy [2]. The thermally ignited pyrotechnic powder near the bridgewire transitions to a sustained combustion front that consumes the remaining material and releases exothermic energy into the surrounding environment [3]. Fundamental studies of the ignition and combustion characteristics of pyrotechnics [4–7], thermites [8, 9], and intermetallics [10] have been conducted by numerous researchers where the material parameters of particle size, bed porosity, and mixture composition have been explored. In pyrotechnic EED development, the interplay between the igniter design aspects and the combustion behavior directly impact the energy released in the surrounding environment. Although many studies have characterized pyrotechnic materials, few studies have quantified overall igniter performance and shock wave output for actual igniter systems. The few published studies on EED device output primarily rely on computational simulations due to the experimental challenges in measuring and visualizing the multiphase, high-luminosity output flow [11, 12]. This work overcomes the experimental challenges associated with qualitative and quantitative characterization of EED output and establishes the techniques useful for follow-on studies assessing the coupled effects of pyrotechnic burn behavior and EED design.
