TECHNOLOGY AREAS: Air Platform, Materials/Processes, Space Platforms, Weapons

OBJECTIVE: Develop kinetics models for the high temperature decomposition products of JP-10 and to validate the kinetics model against experimental data over a range of temperatures, pressures and equivalence ratios relevant to ramjet and scramjet propulsion.

DESCRIPTION: JP-10 (exo-tricyclo[5.2.1.0^2,6]decane, also known simply as C10H16) is a high vapor pressure, dense hydrocarbon fuel suitable for cruise missiles and shipboard environments. The physical properties of JP-10 have been fairly well characterized, however the decomposition chemistry is poorly understood and the few kinetics models that exist are very limited in their ability to reproduce experimental data [1, 2]. The combustion chemistry of JP-10 is highly complex and involves hundreds if not thousands of individual species and thousands of chemical reactions. Numerous efforts [3-9] have been undertaken to characterize the combustion chemistry of JP-10 and develop reduced order combustion chemistry models. A detailed kinetics model capable of predicting the chemical species, transport properties and other important parameters is necessary to understand ignition, flame-holding and combustion behavior in ramjet and scramjet applications. In addition, a detailed kinetics model is necessary to build one ore more reduced-order kinetics models suited to different regions of the temperature, pressure and equivalence ratio ranges relevant to air-breathing propulsion. These models must be suited for use in combustion modeling such as computational fluid dynamics (CFD) and simpler models utilizing codes such as Chemkin and Cantera. Validation of the predictions made with the kinetics model against experimental data will be an important part of this effort.

PHASE I: Identify and define an initial kinetics model that includes transport properties for the decomposition products.

PHASE II: Develop a detailed JP-10 kinetics model that includes transport properties, which can be utilized in computational fluid dynamics (CFD) simulations or other modeling efforts that utilize codes such as Cantera and Chemkin. In addition, documentation that details the model development effort, plus extensive comparison of simulations utilizing the model to experimental data published in the literature.

PHASE III: Work with the government to incorporate the JP-10 kinetics model into new or existing DoD or NASA programs where JP-10 is used as a fuel. A robust JP-10 kinetics model would be used for assessing air-breathing propulsion flow-path performance and also would facilitate the design of combustion systems with shorter combustor lengths.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The aerospace industry will be the primary beneficiary of this STTR. An example of a potential private-sector application is the emerging UAV market. As the requirements for more sensors and other systems increase the demand for available payload space in UAV's, there will likely be a push towards higher energy density fuels to both increase range and available payload space. In addition, propulsion for space access will also benefit from a robust JP-10 kinetics model such as NASA's X37 project, which uses JP-10. It is likely there will be other propulsion systems for space access that will use JP-10 in the future.

REFERENCES:
1. O. Herbinet, B. Sirjean, R. Bounaceur, R. Fournet, B. Battin-Leclerc, G. Scacchi, P.M. Marquaire, "Primary Mechanism of the Thermal Decomposition of Tricyclodecane", J. Phys. Chem, A 2006, Vol. 110, No. 11298.

2. S. Nakra, R.J. Green, S.L. Anderson, "Thermal decomposition of JP-10 studied by microflow tube pyrolysis-mass spectroscopy", Combustion and Flame, Vo. 144, No 4, 2006.

3. D.F. Davidson, D.C. Horning and R.K. Hanson, "Shock Tube Ignition Time Measurements for n-heptane/O2/Ar Mixtures, AIAA 99-2216, 1999.

4. D.F. Davidson, D.C. Horning, J.T. Herbon and R.K. Hanson, "Shock Tube Measurements of JP-10 Ignition", Proceedings of the Combustion Institute, Vol. 28, pp. 1687-1692, 2000.

5. D.F. Davidson, D.C. Horning, M.A. Oehlschlaeger and R.K. Hanson, "The Decomposition Products of JP-10", AIAA 01-3707, 2001.

6. M. Cooper and J.E. Shepherd, "Experiments Studying Thermal Cracking, Catalytic Cracking and Pre-Mixed Partial Oxidation of JP-10", AIAA 03-4867, 2003.

7. M. Cooper and J.E. Shepherd, "Thermal and Catalytic Cracking of JP- for Pulse Detonation Engine Applications", Explosion Dynamics Laboratory Report FM2002.002, California Institute of Technology, December 2002.

8. R. J. Green and S.L. Anderson, "Pyrolysis Chemistry of JP-10", Proceedings of the 13th ONR Propulsion Meeting, ONR, Salt Lake City, UT, 2000, pp 271-276.

9. S.C. Li, B. Varatharajan, F.A. Williams, "The Chemistry of JP-10 Ignition", AIAA Journal, Vol. 39, No. 12, pp. 2351-2356, 2001.

KEYWORDS: JP-10; Combustion; Chemical Kinetics; Transport Properties; CFD; Chemical Decomposition