Further experimental investigations of underwater reactive shaped charge liners and aluminum particle combustion during hypervelocity water impact and penetration

Kovarik, Ryan

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https://hdl.handle.net/2142/46728 Copy

Description

Title

Further experimental investigations of underwater reactive shaped charge liners and aluminum particle combustion during hypervelocity water impact and penetration

Author(s)

Kovarik, Ryan

Issue Date

2014-01-16T18:00:29Z

Director of Research (if dissertation) or Advisor (if thesis)

Glumac, Nick G.

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• aluminum
• combustion
• shaped charge
• water

Abstract

The overall motivation of this project was to continue the investigation of reactive shaped charges. Although significant chemical energy is available in the form of combustion, the coupling of this energy to the target depends critically on the rate and position of energy deposition. Since this information is vital to forecasting damage to the target during the transient event, fundamental combustion knowledge is necessary to understand and predict potential damage behavior. A series of 4 shaped charge tests were conducted. The primary objective of these tests was to investigate the combustion characteristics of large scale reactive liners, with emphasis on the 1-2 ms time range. All tests used 50.75 mm aluminum liners fired into a large tank of water with a series of 11 steel plates installed. Deformation of plates was characterized through use of 5 blue LEDs installed in three target plates (8,9,10). Various means to obtain high speed images in the later time frame included a custom pipe extrusion (Test 2) and a custom timed flash (Test 4). Experimental peak pressure results were on the order of 7000 psi, however, no overpressure was recorded in the 1-2 ms time range. Plate deformation results agree with previous experiments, where there were large plate deformations in unpenetrated plates. The maximum deformation in all tests was 0.462”. High speed imaging during tests indicated that full plate deformation might be achieved no earlier than 1150 μs. This is approximately 500-600 μs before late time combustion as indicated by light emission. A series of 66 light gas gun tests were fired. The primary objective of these tests was to produce an equation for oxidation, an indicator of combustion, as a function of particle size and impact velocity as a supplement to shaped charge experiments. A test matrix consisting of varying particle sizes (5-75μm) and velocities (2500-4000 m/s) was developed. A surface was fit to the data, and an oxidation equation was determined. Based on the data, oxidation is roughly proportional to particle size to the second power, with maximum oxidation occurring in the 25-45 μm range. Data indicate that oxidation is roughly proportional to impact velocity to the first power. Further, preliminary results from tests that varied the depth of water penetrated show that the mechanism for particle combustion takes approximately 4” of water to complete.

Graduation Semester

2013-12

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http://hdl.handle.net/2142/46728

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Copyright 2013 Ryan Kovarik

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