Gaseous, Liquid and Gelled Propellant Hypergolic Reaction Mechanisms
DOD-Army STTR Phase I Contract W911NF-06-C-0127
This STTR Phase I program addresses elucidation of the underlying physics and chemistry associated with ignition delay in hypergolic propulsion systems. More specifically it addresses if the differences observed in ignition delay for liquid and gelled hypergolic propulsion systems are due to mainly physical and/or chemical effects. Mechanisms will be developed for the gas/gas, liquid/liquid and gel/gel hypergolic reactions of mono-methyl hydrazine (MMH) and inhibited red fuming nitric acid (IRFNA) based on literature search, previous research, thermo-chemistry predictions, and engine test results. Reaction mechanisms will include both physical and chemical effects so as to enable prediction of changing ignition delays for the different hypergolic systems being considered. Following mechanism compilation, a set of test methods and apparatus will be devised that provides the best way forward in validating/invalidating the proposed mechanisms.
Gelled hypergolic propellants offer safety advantages inherent to solid phase systems (good handling and storage characteristics, temperature stability, low vapor pressure) while offering performance characteristics similar to liquid phase systems (variable thrust, ability to throttle and turn on and off). However, recent testing of liquid and gelled hypergolic propulsion systems has shown marked differences in ignition delay. Longer than anticipated ignition delays has been associated with engine failure. The results of Phase I program will be crucial to understanding the overall hypergolic reaction mechanism of gelled propellants and to the better deign of current and advanced gas/gas, liquid/liquid or gel/gel hypergolic bipropellant propulsion systems.
The final goal of this program is to develop more effective and efficient gel propellant formulations. Therefore, private industrial, NASA, and DoD propulsion applications would be ideal marketing targets. The emerging private space launch industry would be interested in this capability when evaluating novel ideas that would give them an advantage over traditional government launch services. This interest would be in actual space launch, satellite positioning, and, potentially, providing space travel to civilians. This emerging industry might be very interested in novel approaches to propulsion if they could be confident that their candidates would be hypergolic. Additionally, commercial and small businesses could take advantage of the physical properties of gelled propellants because of the much simpler, safer, and less costly issues associated with handling and transportation.