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Combustion Team

Sara Esparza Cesar Olmedo. Combustion Team. Faculty Advisors:. Student Researchers:. Dr. Guillaume Dr. Wu Dr. Boussalis Dr. Liu. Agenda. Background, Theory & Input Parameters Supersonic Combustion Mach Number & Operational Envelope Engine Design & Optimization Design Components

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Combustion Team

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  1. Sara Esparza Cesar Olmedo NASA Grant URC NCC NNX08BA44A Combustion Team Faculty Advisors: Student Researchers: Dr. Guillaume Dr. Wu Dr. Boussalis Dr. Liu

  2. NASA Grant URC NCC NNX08BA44A Agenda Background, Theory & Input Parameters Supersonic Combustion Mach Number & Operational Envelope Engine Design & Optimization Design Components Design Component Analysis Numerical Analysis and Subsequent Design Modification Future Work Timeline

  3. NASA Grant URC NCC NNX08BA44A Governing Equations:Motion of Fluid Substances • Conservation of Mass • Conservation of Momentum • Conservation of Energy • Conservation of Species • State Equation – Ideal Gas Law

  4. NASA Grant URC NCC NNX08BA44A Combustion Combustion stoichiometry Ideal fuel/ air ratio Recommended fuels for scramjets Hydrogen - most common Ethylene Kerosene Only oxidizer is air In scramjets, combustion is often unstable Equivalence ratio Should range from 0.2 - 2.0 for combustion to occur with a useful time scale Lean mixture ratio below 1.0 Rich mixture ratio above 1.0

  5. NASA Grant URC NCC NNX08BA44A Equivalence and Swirl Ratios:Specific to Combustion Projects • Equivalence Ratio, φ • Swirl Number, S

  6. NASA Grant URC NCC NNX08BA44A Supersonic Combustion

  7. NASA Grant URC NCC NNX08BA44A Supersonic CombustionResearch & Product Description Design, fabricate and test supersonic combustion ramjet in supersonic wind tunnel Research and improve upon high speed flow, mixing, and combustion stability

  8. NASA Grant URC NCC NNX08BA44A Speed of Sound The rate of travel of a sound wave through air under specified conditions γ = adiabatic index R = gas constant T = air temperature At sea level a=768 mi/hr or 343m/s

  9. NASA Grant URC NCC NNX08BA44A Mach Number & Operational Regimes – Subsonic, Transonic, Supersonic & Hypersonic Flight

  10. NASA Grant URC NCC NNX08BA44A Multiple Inward Turning Scoop Reversed Inlet Design Chosen Reversed Alligator Inlet Design Chosen

  11. NASA Grant URC NCC NNX08BA44A Integrated Scramjet Vehicle Compressor Turn Angle 18deg Diffuser Exit angle 12.29 deg Variable Cowl Mach decrease from heat input

  12. NASA Grant URC NCC NNX08BA44A Exit Mach Number One Dimensional Flow

  13. NASA Grant URC NCC NNX08BA44A Shockwaves Traverse through Engine Two-Dimensional Flow

  14. NASA Grant URC NCC NNX08BA44A Shock and Turn Angles

  15. NASA Grant URC NCC NNX08BA44A Prandtl Meyer Expansion Waves

  16. Integrated Scramjet Vehicle NASA Grant URC NCC NNX08BA44A M∞ = 4.5 M = 2.6 M = 4.2 M = 2.1

  17. NASA Grant URC NCC NNX08BA44A Supersonic mixing Ignition and flame holding are a first order issue for supersonic combustion

  18. NASA Grant URC NCC NNX08BA44A Supersonic Combustion – Mixing & Stability Supersonic Mixing Development of mixing length Development of injector location Development of ignition location Development of flame holder

  19. CombustionTurbulent Shear Mixing NASA Grant URC NCC NNX08BA44A

  20. NASA Grant URC NCC NNX08BA44A Turbulent mixing at supersonics speeds Micro-mixing

  21. CombustionTurbulent Shear Mixing Mean velocity profile combines Prandtl’s number Turbulent kinematic viscosity Time average characteristics of turbulent shear NASA Grant URC NCC NNX08BA44A Micro-mixing Fuel wave Fuel vortex

  22. CombustionTurbulent Shear Mixing Shear layer width – Two methods NASA Grant URC NCC NNX08BA44A Local shear layer width for turbulent shear mixing Recent research Cδ is a experimental constant

  23. CombustionTurbulent Shear Mixing Density effects on shear layer growth – compressible flow Based on constant but different densities A density ratio, s, is derived s can be calculated once stagnation pressure and stream velocities are known NASA Grant URC NCC NNX08BA44A

  24. CombustionTurbulent Shear Mixing Convective velocity for the vortex structures With compressible flow using isentropic stagnation density equation changes to NASA Grant URC NCC NNX08BA44A

  25. CombustionTurbulent Shear Mixing Density correct expression for shear layer growth including compressibility effects NASA Grant URC NCC NNX08BA44A

  26. CombustionTurbulent Shear Mixing NASA Grant URC NCC NNX08BA44A

  27. NASA Grant URC NCC NNX08BA44A Supersonic Mixing Efficiency • Mixing Efficiency

  28. NASA Grant URC NCC NNX08BA44A Fuel • Hydrogen • Has four times the energy of aviation fluid, less polluting emissions • Safety • Silane • SiH4 is a pyrophoric that can be added to hydrogen to decrease ignition delay time of the fuel • Concentrations are between 5-20% by volume • Useful when the combustion chamber is short or combustion chamber temperature is low • Safety Concerns : is highly explosive easily ignites with air and 9.6k ppm is very lethal in just a four hour exposure • JP–10 Fuel • Liquid Fuel used in First air-breathing Scramjet

  29. NASA Grant URC NCC NNX08BA44A Combustion Stability Flame velocity Flame length Recirculation Detonation Auto-ignition Back pressure

  30. Mach 2 Simple Mutable Flexible Rapid prototype ZPrinter powder, high temperature inner shell Cheap MFDCLab sufficient Mach 4.5 Complex Fixed shape Not flexible Machining Stainless steel, high nickel steel, copper, aluminum Expensive Needs supersonic wind tunnel NASA Grant URC NCC NNX08BA44A Design Approaches

  31. NASA Grant URC NCC NNX08BA44A Combustion Performance & Design Detonation – shockwave induced combustion Flame holder – use back pressure to control flame stability COSMOSWorks Flame Holder Inlet Mach 4.5 Velocity contours shows recirculation zones

  32. NASA Grant URC NCC NNX08BA44A Injector Pressure Profile

  33. NASA Grant URC NCC NNX08BA44A Fuel Injector Holds the Flame

  34. NASA Grant URC NCC NNX08BA44A Size Coolant Delivery Mechanism according to Pressure and Temperature

  35. NASA Grant URC NCC NNX08BA44A Proof of Concept • Test supersonic leading edges • Develop and simulate computational fluid dynamics run of overall design and individual components • Compare and analyze test data • Achieve supersonic combustion throughout the engine

  36. NASA Grant URC NCC NNX08BA44A Conclusion Sustain supersonic combustion Increase fuel and air mixing time Vary input parameters to create knowledge and testing base Key components Multiple combustion chambers Cavities Flameholders Development of a doctoral dissertation

  37. Textbook References Anderson, J. “Compressible Flow.” Anderson, J. “Hypersonic & High Temperature Gas Dynamics” Curran, E. T. & S. N. B. Murthy, “Scramjet Propulsion” AIAA Educational Series, Fogler, H.S. “Elements of Chemical Reaction Engineering” Prentice Hall International Studies. 3rd ed. 1999. Heiser, W.H. & D. T. Pratt “Hypersonic Airbreathing Propulsion” AIAA Educational Searies. Olfe, D. B. & V. Zakkay “Supersonic Flow, Chemical Processes, & Radiative Transfer” Perry, R. H. & D. W. Green “Perry’s Chemical Engineers’ Handbook” McGraw-Hill Turns, S.R. “An Introduction to Combustion” White, E.B. “Fluid Mechanics”. NASA Grant URC NCC NNX08BA44A

  38. Journal References NASA Grant URC NCC NNX08BA44A Allen, W., P. I. King, M. R. Gruber, C. D. Carter, K. Y Hsu, “Fuel-Air Injection Effects on Combustion in Cavity-Based Flameholders in a Supersonic Flow”. 41st AIAA Joint Propulsal. 2005-4105. Billig, F. S. “Combustion Processes in Supersonic Flow”. Journal of Propulsion, Vol. 4, No. 3, May-June 1988 Da Riva, Ignacio, Amable Linan, & Enrique Fraga “Some Results in Supersonic Combustion” 4th Congress, Paris, France, 64-579, Aug 1964 Esparza, S. “Supersonic Combustion” CSULA Symposium, May 2008. Grishin, A. M. & E. E. Zelenskii, “Diffusional-Thermal Instability of the Normal Combustion of a Three-Component Gas Mixture,” Plenum Publishing Corporation. 1988. Ilbas, M., “The Effect of Thermal Radiation and Radiation Models on Hydrogen-Hydrocarbon Combustion Modeling” International Journal of Hydrogen Energy. Vol 30, Pgs. 1113-1126. 2005. Qin, J, W. Bao, W. Zhou, & D. Yu. “Performance Cycle Analysis of an Open Cooling Cycle for a Scramjet” IMechE, Vol. 223, Part G, 2009. Mathur, T., M. Gruber, K. Jackson, J. Donbar, W. Donaldson, T. Jackson, F. Billig. “Supersonic Combustion Experiements with a Cavity-Based Fuel Injection”. AFRL-PR-WP-TP-2006-271. Nov 2001 McGuire, J. R., R. R. Boyce, & N. R. Mudford. Journal of Propulsion & Power, Vol. 24, No. 6, Nov-Dec 2008 Mirmirani, M., C. Wu, A. Clark, S, Choi, & B. Fidam, “Airbreathing Hypersonic Flight Vehicle Modeling and Control, Review, Challenges, and a CFD-Based Example” Neely, A. J., I. Stotz, S. O’Byrne, R. R. Boyce, N. R. Mudford, “Flow Studies on a Hydrogen-Fueled Cavity Flame-Holder Scramjet. AIAA 2005-3358, 2005. Tetlow, M. R. & C. J. Doolan. “Comparison of Hydrogen and Hydrocarbon-Fueld Scramjet Engines for Orbital Insertion” Journal of Spacecraft and Rockets, Vol 44., No. 2., Mar-Apr 2007.

  39. Acknowledgements Thanks to the faculty advisors: Dr. D. Guillaume Dr. C. Wu And SPACE Center faculty: Dr. H. Boussalis Dr. C. Liu SPACE Center Students Combustion Team Sheila Blaise Rebecca Winfield NASA Grant URC NCC NNX08BA44A

  40. NASA Grant URC NCC NNX08BA44A Timeline2009 - 2010

  41. NASA Grant URC NCC NNX08BA44A Timeline2010 - 2011 2011 Timeline Excel

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