Investigation of enhanced aluminum casings for underwater explosives and development of spectroscopic techniques for measuring temperature in environments relevant to underwater ordnance

Enhanced aluminum casings for high explosives were examined both experimentally and theoretically. The experimental analysis utilized aluminum cylinders with linear shaped charges embedded on the surface. The cavities produced jets which outperformed the regions on the cylinder without cavities in terms of enhanced radial bubble growth. It was also shown that cavities with sharp angles at the apex performed better at increasing the bubble volume as opposed to linear cavities with rounded geometries. The theoretical work analyzed the enhancement of aluminum spheres with conical cavities. The radial position of the gas bubble exhibited similar trends to the experimental data for regions with and without cavities based on the penetration of a shaped charge into water. When the cavity liners were designed with the standard guidelines of shaped charge design, the energy potential associated with the displaced explosive was greater than the energy contained in the aluminum cavity liner. If the design guidelines were neglected, the enhanced casings were feasible both on a velocity/penetration distance analysis and energy basis. The energy requirement could also be satisfied, without modifying the design constraints, by filling the cavities with aluminum powder to increase the mass of aluminum in the system. Two novel spectroscopic temperature measurements were performed on two different underwater systems. A fiber-bundle-coupled emission spectrometer with the input fiber ends anchored along a thin plate near the source provided access to the internal structure of aluminum powder reacting in an underwater environment. This system was sensitive to alignment of the gauge with the combustion event, the intensity of emission from the combustion bubble, and the location of the emission within the gas bubble. An absorption spectrometer was utilized to determine a time-resolved electronic temperature pro file for an iron gas bubble created by an underwater electrical wire explosion. Accounting for the refractive properties of the gas bubble was a critical aspect in transmitting the absorption light source through the bubble and then collecting and focusing the light into the spectrometer. The fitted temperatures for a time period of 200-700 microseconds after the trigger were 3350-3580 K with an uncertainty of +/- 500 K. Additional work should investigate applying this technique to a high explosive underwater.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2013

Author dc:creator

• Kingston, Lance

Contributors dc:contributor

• Glumac, Nick G.
• Krier, Herman
• Stewart, Donald S.
• Austin, Joanna M.

• Underwater
• Explosive
• Shaped Charge
• Spectroscopy
• Bubble
• Emission
• Absorption
• Aluminum
• Temperature

Statement dc:rights

• Copyright 2013 Lance Kingston

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/44792

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/44792