Control of ignition delay in microfabricated hot-wire igniters: Simulation, fabrication, and experimental results

The presented work studied thermal interactions between laminated, metal-foil, hot-wire igniters and exothermic solid-state, composite chemical systems in order to demonstrate precise timing control of a thermal ignition process. The study includes FEA modeling, device fabrication, and characterization to demonstrate control microthruster ignition delays to within 2 ms. The modeling included studies of total ignition delay as well as the ignition delay variation versus process variations. Microthrusters were then fabricated via printed circuit board lamination, and the ignition performance was characterized. The characterization showed agreement with modeling to within 2-sigma for most cases. And the characterization demonstrated that the ignition delay could be controlled to within 0.36 and 0.84 ms for the best case. Furthermore, this performance was demonstrated with a small battery supply (200–600 mAh) and minimal electronics in the ignition system. This work extends the use of current microthrusters to short-lifetime applications that need high forces delivered in millisecond time intervals.

Figure optionsDownload as PowerPoint slideHighlights
► The thermal interactions between hot-wire igniters and solid composite propellants are studied for control of the ignition process.
► Devices leverage lamination packaging and batch fabrication.
► FEA and device characterization showed that the hot-wire fused within 2 ms width.
► Characterization demonstrated that the ignition delay could be controlled to within 0.36 and 0.84 ms.