<p>Additive manufacturing of gun
propellants is an emerging and promising field which addresses the limitations
of conventional manufacturing techniques. Gun propellants are manufactured
using wetted extrusion, which uses volatile solvents and dies of limited and
constant geometries. On the other hand, additive techniques are faced with the challenges
of maintaining the gun propellant’s energetic content as well as its structural
integrity during high pressure combustion. The work presented in this thesis demonstrates
the feasibility of producing functioning gun propellant grains using vibration-assisted
3D printing, a novel method which has been shown to extrude extremely viscous materials
such as clays and propellant pastes. At first, the technique is compared to
screw-driven additive methods which have been used in printing gun propellant
pastes with slightly lower energetic content. In chapter two, diethylene glycol dinitrate (DEGDN), a
highly energetic plasticizer, was investigated due to its potential to replace
nitroglycerin in double base propellants with high nitroglycerin content. A
novel isoconversional method was applied to analyze its decomposition kinetics.
The ignition and lifetime values of diethylene
glycol dinitrate were obtained using the new isoconversional method, in
order to assess the safety of using the plasticizer
in a modified double base propellant. In chapter three, a modified double base
propellant (M8D) containing DEGDN was additively manufactured using VAP. The
printed strands had little to no porosity, and their density was nearly equal
to the theoretical maximum density of the mixture. The strands were burned at
high pressures in a Crawford bomb and the burning was visualized using high
speed cameras. The burning rate equation as a function of the M8D propellant as
a function of pressure was obtained. Overall, this work shows that VAP is
capable of printing highly energetic gun propellants with low solvent content,
low porosity, with high printing speeds, and which have consistent burning
characteristics at high pressures. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/14524176 |
| Date | 05 May 2021 |
| Creators | Aaron Afriat (10732359) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/COMBUSTION_CHARACTERISTICS_OF_ADDITIVELY_MANUFACTURED_GUN_PROPELLANTS/14524176 |
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