Opportunity at Air Force Research Laboratory (AFRL)
Bench Top Energetics
Munitions Directorate, RW/Ordnance Division
||Eglin Air Force Base, FL 325426810
|Fajardo, Mario E.
The incorporation of nanometric (sub-micron size) metal fuel and oxidizer particles into energetic materials is a promising approach to increasing significantly the systems-level performance of munitions. We propose to exploit the phenomenon of laser driven shock initiation of energetic materials to enable bench-scale testing of initiation mechanisms and energy-release reaction kinetics of nanometric energetic materials using methods which utilize a minimum of often rare and expensive energetic materials, and which routinely yield rapid repetitive energetic events. Direct laser initiation of energetic materials involves a complicated combination of shock, electronic, and thermal effects which are very difficult to relate to real-world chemical-explosive-driven initiation processes. We will use laser driven flyer plates to decouple the laser photon flux from the energetic material, reducing interference from direct electronic and thermal initiation mechanisms, thus greatly simplifying matters. The technology for producing laser driven flyers is advancing rapidly, thanks to efforts in a number of laboratories around the world. We will exploit as much of the state-of-the-art as feasible, including the use of advanced numerical simulation techniques to model our benchtop experiments. We will adopt the “nanoshock target array” approach for generating repetitive energetic events. In this method thin films of energetic materials are prepared on a transparent substrate “target coupon” which is rastered mechanically through the fixed focus of a pulsed laser beam. Our novel adaptation will include the laser driven flyer plate intermediate and a target-in-vacuum capability. The expansion of reaction intermediates into vacuum will quench subsequent reactions and preserve these intermediates for spectroscopic interrogation. Conversely, we will also employ buffer gases and “glass confined” experimental geometries as necessary to permit longer reaction times. The spectroscopic diagnostics will permit testing of common modeling assumptions, such as local thermodynamic equilibrium, and will be capable of measuring conditions in the reacting flow such as rotational and vibrational temperatures.
Fossum EC, et al: Prop. Expl. Pyro. 37: 445, 2012
Nanometric energetic materials; Laser driven shocks; Laser driven flyer plates; Spectroscopic diagnostics;
Open to U.S. citizens and permanent residents
Open to Postdoctoral and Senior applicants