Date of Award
Fall 2014
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Aeronautics and Astronautics
First Advisor
Stephen D. Heister
Second Advisor
Steven F. Son
Committee Chair
Stephen D. Heister
Committee Co-Chair
Steven F. Son
Committee Member 1
Sally P. Bane
Committee Member 2
Timothee L. Pourpoint
Abstract
Hypergolic hybrid rockets have the potential of providing systems that are simple, reliable, have high performance, and allow for energy management. Such a propulsion system can be applied to fields that need a single tactical motor with flexible mission requirements of either high speed to target or extended loitering. They also provide the possibility for alternative fast response dynamic altitude control systems if ignition delays are sufficiently short. ^ Amines are the traditional fuel of choice when selecting a hypergolic combination as these tend to react readily with both nitric acid and dinitrogen tertroxide based oxidizers. It has been found that the addition of a borane adduct to an amine fuel tends to reduce the ignition delay by up to an order of magnitude with white fuming nitric acid (WFNA). The borane addition has resulted in fuels with very short ignition delays between 2-10 ms - the fastest times for an amine based fuel reacting with nitric acid based oxidizers. The incorporation of these amine-boranes, specifically ethylenediamine bisborane (EDBB), into various fuel binders has also been found to result in ignition delays between 3-10 ms - the fastest times again for amine based fuels. ^ It was found that the addition of a borane to an amine increased theoretical performance of the amine resulting in high performance fuels. The amine-borane/fuel binder combinations also produced higher theoretical performance values than previously used hypergolic hybrid rockets. Some of the theoretical values are on par or higher than the current toxic liquid hypergolic fuels, making amine boranes an attractive replacement. The higher performing amine-borane/fuel binder combinations also have higher performance values than the traditional rocket fuels, excluding liquid hydrogen. Thus, amine-borane based fuels have the potential to influence various area in the rocket field. ^ An EDBB/ferrocene/epoxy fuel was tested in a hypergolic hybrid with pure nitric acid as the oxidizer. Hypergolic ignition occurred repeatably and with short combustor pressurization times of under 100 ms. The regression rate of the fuel exhibited never before observed high pressure dependence regression rates. The presence of a foam like layer on the fuel surface provides an adequate explanation for the observed combustion behavior with a calculated regression rate that depends on pressure raised to the 2nd power. Extrapolation of this theory indicates that amine-borane based fuels could produce high regression rate fuels.
Recommended Citation
Pfeil, Mark A., "Solid amine-boranes as high performance hypergolic hybrid rocket fuels" (2014). Open Access Dissertations. 347.
https://docs.lib.purdue.edu/open_access_dissertations/347