K. Clements thesis revised 5.pdf (4.99 MB)

AN EXPERIMENTAL STUDY OF FACTORS AFFECTING HYPERGOLIC IGNITION OF AMMONIA BORANE

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thesis
posted on 21.04.2020, 20:03 by Kathryn A Clements
Hypergolic hybrid motors are advantageous for rocket propulsion due to their simplicity, reliability, low weight, and safety. Many hypergolic hybrid fuels with promising theoretical performance are not practical due to their sensitivity to temperature or moisture. Ammonia borane (AB) has been proposed and studied as a potential hypergolic hybrid fuel that provides both excellent performance and storability. This study investigates the effect of droplet impact velocity, pellet composition, and storage humidity on ignition delay of AB with white fuming nitric acid as the oxidizer. Most ignition delays measured were under 50 ms with many under 10 ms and some even under 2 ms, which is extremely short for hybrid systems. Higher droplet velocities led to slightly shorter ignition delays, and exposing samples to humidity slightly increased ignition delay. An AB pellet composition of at least 20% epoxy binder was found to minimize ignition delay. The epoxy facilitates ignition by absorbing or adhering the oxidizer and slowing the reaction with the fuel, preventing oxidizer expulsion and holding it close to the fuel. These results emphasize the importance of binder properties in hypergolic hybrids. Pellets varying in composition and storage method were extinguished and reignited with the oxidizer to demonstrate reignition capability.

Funding

Graduate Research Fellowship Program (GRFP)

Directorate for Education & Human Resources

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Surface Chemistry and Combustion Behavior of Hypergolic Solid Fuels

United States Army

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Development of High-Performance Ammonia Borane Based Rocket Propellants, NASA NSTRF

Laura Winkelman Davidson Fellowship, Purdue University

History

Degree Type

Master of Science in Mechanical Engineering

Department

Mechanical Engineering

Campus location

West Lafayette

Advisor/Supervisor/Committee Chair

Steven Son

Additional Committee Member 2

Timothee Pourpoint

Additional Committee Member 3

Terrence Meyer

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