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Hypergolic Combustion. Allyssa Stanley December 9, 2009. Hypergolic Combustion. Motivation With a push for further space exploration it is important to develop better propellants
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Hypergolic Combustion Allyssa Stanley December 9, 2009
Hypergolic Combustion • Motivation • With a push for further space exploration it is important to develop better propellants • While hypergolic propellants have been thoroughly researched in the past, new developments and applications are creating the need for further study into the field • Project Goal • Obtain a fundamental understanding of hypergolic combustion and observe its usage in the space industry • Objectives • Develop an understanding of hypergolics • Run a CEA analysis on the primary hypergolic propellants • Run a CEA analysis on the secondary hypergolic propellant • Compare the two results • Approach • Literature review • Development of a physical model • Solution using NASA CEA software • Analysis of the results
Hypergolic Combustion: Source • Literature Review • Simmons, J A et al. “Reactions and Expansion of Hypergolic Propellants in a Vacuum." AIAA Journal 6.5 (May 1968) : 887-893. Print. • Was solely focused on the combustion of hypergolic propellants • Seamans, Thomas F et al. “Development of a Fundamental Model of Hypergolic Ignition in Space-Ambient Engines." AIAA Journal 5.9 (Sept 1967) : 1616-1624. Print.[ • Physical application of hypergolic combustion theory • Stanley, Douglas O & Roland M. Martinez. “Comparative Assessment of Lunar Propellant Options." Journal of Spacecraft and Rockets 45.4 (July-Aug 2008): 776-784. Print.[ • Discussed directly the benefits of hypergolic propellants versus other types • The combustion attributes of hypergolic propellants were only covered briefly • Nusca, Michael J et al. “Modeling Hypergolic Ignition in the Army’s Impinging Stream Vortex Engine Including Injection Throttling." 43rd AIAA/ASME/ASEE Joint Propulsion Conference and Exhibit (8-11 July 2007) • Illustrated the need for new research involving hypergolic combustion • Did not deal with hypergolic usage in space systems • Grayson, Gary D & Daniel A Watts. “Nitrous Oxide and Ethanol Propulsion Concepts for a Crew Space Vehicle." 43rd AIAA/ASME/ASEE Joint Propulsion Conference and Exhibit (8-11 July 2007) • Discussed the combustion of a rival propulsion system
Hypergolic Combustion: Overview • Propellants ignite upon contact, requiring no separate ignition source • Very fast reaction • Most hypergolic propellants can be stored at STP • Highly useful for space application • Drawback is the high toxicity for humans
Case 1 Recreation of Nusca Case 2 Recreation of the hypergolic combustion used on the space shuttle Case 3 Look at how the addition of NO affects case 2 Hypergolic Combustion: Cases
Hypergolic Combustion: Assumptions • Thermodynamic values utilized for CEA code • (A/F) = 2.6 • Tin (MMH)= 298.15 K -requirement of CEA • Tin = 300 K • Pin = 1850 psia • Product restrictions • CO, CO2, H, HNO, HO2, H2, H2O, H2O2, NO, NO2, N2, O, OH & O2
Case 1 Results The CEA results for Temperature closely match those obtained by Nusca when the engine reached steady state.
Case 2 Results We see a an increase in temperature as well as an increase in the N2 production
Case 3 Results As a result of the addition of NO we again have an increase in combustion temperature. These are not the results expected
Hypergolic Combustion: Results • Case 1: Recreation of Nusca • Case 2: Recreation of the hypergolic combustion used on the space shuttle • Case 3: Look at how the addition of NO affects case 2 • The CEA results for Case 1 closely matched the theoretical results of Nusca • The combustion temperature for Case 2 was higher than that of Case 1, but still relatively close. • The use of HNO3 versus N2O4 is not temperature dependent. Should look at other factors when deciding on an oxidizing agent such as cost and handling safety
Hypergolic Combustion: Conclusions • Conclusions • While a basic tool, NASA CEA is highly reliable and with appropriate assumptions even more complicated combustion problems can be analyzed. • Further research can involve reducing the assumptions and adding more variables: • Alter (A/F) for each case to be stoichiometric respectively • Run a non restricted product analysis • Vary input temperatures and pressures • What needs to be improved • Addition of various extra elements to improve performance • A more detailed review of combustion reactions • Designing a new CFD program to analyze more fully hypergolic combustion • Designing a new hypergolic engine that more efficiently utilizes hypergolic propellants