The Design of a Hybrid Rocket Engine

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Kazuo Inamori School of Engineering at Alfred University
In this thesis a hybrid rocket engine will be designed and built to experimentally test different materials which can be used for fuel. Hybrid rockets contain both a solid propellant such as hydroxyl-terminated polybutadiene (HTPB) or paraffin wax and a gaseous oxidizer such as liquid oxygen (o2). The most recent research has been using Acrylonitrile butadiene styrene (ABS) as the solid propellant. The advantages of using ABS plastic are that it produces a thrust comparable to other propellants, it is affordable, and it can be three dimensionally printed to transform into any shape. Disadvantages of using ABS are its low melting point, causing a lower thrust, and it burns faster than traditional hybrid rocket propellants. Due to its low melting point and faster burn rates, an experiment was conducted where ABS and aluminum nanoparticle flakes were combined to solve this problem. A small scale hybrid rocket stand was designed in Solidworks™ and then built. The next step was to discover a method that would make the combined ABS and aluminum nanoparticles into a shape that could be used in the 3D printer. A filament extruder was then designed and built. ABS was dissolved with acetone and mixed with aluminum to become a plastic/metal propellant for the hybrid rocket. Once that plastic/metal material was bound together, it was then able to undergo heat and pressure in the filament extruder to become a 1.75 millimeter in diameter string that could be 3D printed. Once this plastic/metal material is able to be 3D printed, the aluminum will achieve higher melting temperatures producing greater thrust values.
Advisory committee members: Ehsan Ghotbi, Joseph Kirkland. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Mechanical Engineering at the Inamori School of Engineering at Alfred University