Combustion Team Faculty Advisors: Dr. Guillaume Dr. Wu Dr. Boussalis Dr. Liu Sara Esparza Cesar Olmedo Student Researchers: 1NASA 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 2NASA Grant URC NCC NNX08BA44A

Governing Equations: Motion of Fluid Substances Conservation of Mass Conservation of Momentum State Equation – Ideal Gas Law Conservation of Species Conservation of Energy 3NASA 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 for combustion to occur with a useful time scale Lean mixture ratio below 1.0 Rich mixture ratio above 1.0 4NASA Grant URC NCC NNX08BA44A

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

Supersonic Combustion 6NASA Grant URC NCC NNX08BA44A

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

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

Mach Number & Operational Regimes – Subsonic, Transonic, Supersonic & Hypersonic Flight Subsonic Boeing 747 0<Ma<1 Ma =.85 Supersonic F15 Fighter Plane 1.0<Ma<3.0 Ma =1.5 Hypersonic Space Shuttle Ma>3 Ma =25 9NASA Grant URC NCC NNX08BA44A

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

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

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

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

Shock and Turn Angles 14NASA Grant URC NCC NNX08BA44A

Prandtl Meyer Expansion Waves 15NASA Grant URC NCC NNX08BA44A

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

Supersonic mixing Ignition and flame holding are a first order issue for supersonic combustion 17NASA 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 18NASA Grant URC NCC NNX08BA44A

Combustion Turbulent Shear Mixing 19NASA Grant URC NCC NNX08BA44A

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

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

Combustion Turbulent Shear Mixing Shear layer width – Two methods Local shear layer width for turbulent shear mixing Recent research C δ is a experimental constant 22NASA Grant URC NCC NNX08BA44A

Combustion Turbulent 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 23NASA Grant URC NCC NNX08BA44A

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

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

Combustion Turbulent Shear Mixing 26NASA Grant URC NCC NNX08BA44A

Supersonic Mixing Efficiency Mixing Efficiency 27NASA 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 28NASA Grant URC NCC NNX08BA44A

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

Design Approaches 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 30NASA 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 31NASA Grant URC NCC NNX08BA44A

Injector Pressure Profile 32NASA Grant URC NCC NNX08BA44A

Fuel Injector Holds the Flame 33NASA Grant URC NCC NNX08BA44A

Size Coolant Delivery Mechanism according to Pressure and Temperature PcMechanism 700tubes 1310tubes 1378channels/tubes 1486channels/ablative 2994channels/tubes 34NASA 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 35NASA 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 36NASA Grant URC NCC NNX08BA44A

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. 3 rd ed 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”. 37NASA Grant URC NCC NNX08BA44A

Journal References 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”. 41 st AIAA Joint Propulsal 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” 4 th Congress, Paris, France, , Aug 1964 Esparza, S. “Supersonic Combustion” CSULA Symposium, May Grishin, A. M. & E. E. Zelenskii, “Diffusional-Thermal Instability of the Normal Combustion of a Three-Component Gas Mixture,” Plenum Publishing Corporation Ilbas, M., “The Effect of Thermal Radiation and Radiation Models on Hydrogen-Hydrocarbon Combustion Modeling” International Journal of Hydrogen Energy. Vol 30, Pgs Qin, J, W. Bao, W. Zhou, & D. Yu. “Performance Cycle Analysis of an Open Cooling Cycle for a Scramjet” IMechE, Vol. 223, Part G, 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 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 , 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 NASA Grant URC NCC NNX08BA44A

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 39NASA Grant URC NCC NNX08BA44A

Timeline Supersonic Combustion Team Timeline: March February Student NameMARAPRMAYJUNJULAUGSEPOCTNOVDECJANFEB Sara Esparza Understanding Compressible Flow Determination of Mach Speed inside Diffuser Determined Fuel Selection Hydrogen & Ethylene Boundary Layer Theory Develop shear mixing layer Begin research on Thesis Development Fuel SelectionPresentation Begin research on fuel igniter locator Began Research on diffuser exhaust Presentation Dr. Spanos Presentation Supersonic Diffuser Initial Design Angle Determination of Diffuser Shear stress in compressible & non compressible flow Determine Shear Layer in compressible & non compressible flow Begin writing Thesis Determined that Ethylene is better than Hydrogen, and mixing efficiency Begin research on fuel injection angles Using mixing layer theory, determined igniter location Design SECETA Supersonic diffuser with Prandtl-Myer expansion Research on Flame Holder Concept Science Symposium Presentation Cosmos CFD analysis of Diffuser CFD Analysis of Mach Speed & Shock Wave Angles Determine difference in shear layer growth between compressible & non compressible flows Determined efficiency of mixing dependent of injection angle Determine the angle of injection Determined igniter should be continuous like a spark plug CFD analysis of SECETA Paper for Colorado Conference Cesar Olmedo Understanding Compressible Flow CFD Analysis of Mach Speed & Shock Wave Angles Determined Fuel Selection Hydrogen & Ethylene Understand Supersonic Mixing Develop shear mixing layer Begin research on Thesis Development and writing Thesis Fuel SelectionPresentation Begin research on fuel igniter locator Began Research on diffuser exhaust Presentation Dr. Spanos Presentation Boundary Layer Theory Fuel Selecti on Determine Shear Layer in compressible & non compressible flow Determined that Ethylene is better than Hydrogen, and mixing efficiency Begin research on fuel injection angles Using mixing layer theory, determined igniter location Design SECETA Supersonic diffuser with Prandtl-Myer expansion Research on Flame Holder Concept Science Symposium Presentation Cosmos CFD analysis of Diffuser Shear stress in compressible & non compressible flow Determine difference in shear layer growth between compressible & non compressible flows Determined efficiency of mixing dependent of injection angle Determine the angle of injection Determined igniter should be continuous like a spark plug CFD analysis of SECETA Design of Flame Holder Paper for Colorado Conference 40NASA Grant URC NCC NNX08BA44A

Timeline Timeline Excel Supersonic Combustion Team Timeline: March February Student Name MARAPRMAYJUNJULAUGSEPOCTNOVDECJANFEB Sara Esparza Duel cavity flame holder is selected Engineering Drawing of Flame Holder Material Selection for flame holder (Copper) CFD analysis of Flame holder Presentation Fabrication of Flame Holder Integration of SECETA and Flame Holder Application of Sensors on SECETA Fabricate Fuel line to Wind tunnel Supersonic Wind tunnel Testing Set up fuel lines in wind tunn el Attempt Supersonic Combustion Gather Data Attempt Multiple combustion Chamber Determine thrust of engine Determine Combustion time Developed cost to determined Budget First cavity is adjustable Determined if Budget can be obtained Cesar Olmedo Duel cavity flame holder is selected Engineering Drawing of Flame Holder Material Selection for flame holder (Copper) CFD analysis of Flame holder Presentation Fabrication of Flame Holder Integration of SECETA and Flame Holder Application of Sensors on SECETA Fabricate Fuel line to Wind tunnel Supersonic Wind tunnel Testing Set up fuel lines in wind tunn el Attempt Supersonic Combustion Gather Data Attempt Multiple combustion Chamber Determine thrust of engine Determine Combustion time Developed cost to determined Budget First cavity is adjustable Determined if Budget can be obtained Alonzo Perez Engineering Drawing of Flame Holde Attempt Supersonic Combustion Gather Data Attempt Multiple combustion Chamber Determine thrust of engine Determine Combustion time 41NASA Grant URC NCC NNX08BA44A