421073 Hypergolic Combustion of Nitric Acid with Protonated Dicyanamide and with Nitro-Dicyanamide-Carbonyl: A Reactive Molecular Dynamics Study

Wednesday, November 11, 2015: 10:15 AM
Canyon A (Hilton Salt Lake City Center)
Chad Junkermeier, Mechanical & Nuclear Engineering, Penn State University, University Park, PA, Michael R. Weismiller, Naval Research Laboratory, Washington, DC, Dmitry Bedrov, Materials Science and Engineering, University of Utah, Salt Lake City, UT and Adri C.T. van Duin, Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA

Ionic liquids are of interest as much less volatile and less toxic replacements for current hypergolic fuels.  One such ionic liquid is dicyanamide (DCA), which when it reacts with nitric acid (HNO3) has the predicted reaction mechanism DCA -> protonated DCA (DCAH) -> nitro-dicyanamide-carbonyl (NDC) -> 1,5-Dinitrobiuret (DNB) -> combustion.  To better understand the reaction dynamics of DCA, we used a ReaxFF reactive force field to perform molecular dynamics simulations of mixtures HNO3 with DCA (DCAH) and with NDC.  To investigate the reaction in a dense vapor and liquid phase, simulations were performed at both low (0.25 g/ml) and high (1.00 g/ml) densities.  DCAH and NDC each react hypergolically with HNO3 with increased density leading to shorter times for the onset of thermal runaway.  Neither DCAH nor NDC are converted to 1,5-Dinitrobiuret (DNB) before thermal runaway, suggesting a new reaction path may need to be considered.

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See more of this Session: Interfacial Phenomena in Ionic Liquids
See more of this Group/Topical: Engineering Sciences and Fundamentals