Design, fabrication and characterization of an electrical-explosively actuated MEMS flyer-accelerator inserted with parallel bridge foils

Abstract

Parallel bridge foils (PBF) with four strip foils, which is derived from traditional single bridge foil (SBF), was designed to study the effect of convergence and collision of plasmas and shock waves on driving flyer. Firstly, Electro-thermal simulation of PBF was performed to analyze temperature distribution before melting, which predicted the synchronous burst characteristic of PBF. Subsequently, a capacitor discharging circuit was designed to initiate bridge foils, results indicated PBF reached higher burst power in shorter time compared with SBF due to better matching between PBF and the test circuit. The flow fields of electrical explosion of bridge foils were photographed by ultra-high-speed camera, which displayed PBF almost burst simultaneously. Moreover, PBF had wider and brighter flow field visualization than SBF owing to convergence and superposition of plasma beams. Most importantly, flyer-accelerators inserted with bridge foils were prepared by MEMS technology, and comparative analysis from PDV revealed MEMS flyer-accelerator inserted with PBF had access to better velocity performances, compared with that inserted with SBF. For instance, PBF flyer-accelerator spent mere 168 ns to 2325 m/s at 900 V/0.22 µF, but SBF flyer-accelerator took 335 ns to 1073 m/s. Finally, we proposed a mathematical model for explaining the enhancement effect of flyer velocity, which to some extent showed good agreement with experimentation.