Combustion Team Supersonic Combustion 6/17/2015NASA Grant URC NCC NNX08BA44A Faculty Advisors: Dr. Guillaume Dr. Wu Dr. Boussalis Dr. Liu Sara Esparza Cesar Olmedo Alonzo Perez Student Researchers:

Supersonic Combustion Hypersonic Flight Agenda Background Governing Equations Mach Number & Operational Envelope Supersonic Mixing & Flame Holder Engine Design, Components, and Optimization Current Progress Future Work Cost Analysis Timeline 6/17/2015NASA Grant URC NCC NNX08BA44A

Background United Air Force (UAF) requires further testing and understanding during the conceptual design phase Hypersonic Capabilities NASA considers a more viable and cost effective method of space exploration Hypersonic vehicle Combustion team is developing propulsion systems for air breathing supersonic combustion ramjet or scramjets Primary issues of concern Supersonic mixing – air and fuel mixing length increases chamber length which decreases profit and increases weight and size Combustion – stability to overcome flame blow-out 6/17/2015NASA 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 6/17/2015NASA Grant URC NCC NNX08BA44A

6/17/2015NASA Grant URC NCC NNX08BA44A Combustion Combustion stoichiometry Ideal fuel/ air ratio Recommended fuels for scramjets Hydrogen - most common Ethylene Kerosene Air-breathing engine - oxidizer is air 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

Equivalence and Swirl Ratios: Specific to Combustion Projects Equivalence Ratio, φ 6/17/2015NASA 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 NASA Grant URC NCC NNX08BA44A 6/17/2015

Mach Number & Operational Regimes – Subsonic, Transonic, Supersonic & Hypersonic Flight Subsonic Boeing 747 0<Ma<1.0 Ma =0.85 Supersonic F18 Fighter Plane 1.0<Ma<3.0 Ma =1.5 Hypersonic Space Shuttle Ma>3.0 Ma =25.0 6/17/2015NASA Grant URC NCC NNX08BA44A

Engine Design Process Mission Definition Vehicle Selection Engine Requirements Technology Limits Engine Candidate Optimization Engine Selection Engine Preliminary Design Engine Component Design Engine Component Finalized Design Component Definition 6/17/2015 NASA Grant URC NCC NNX08BA44A

Design Process and Verification Mach 2 Current design effort Lower mach speed Initial setup to test supersonic combustion stability Proof of concept Economical Variable materials Mach 4.5 Future work Higher mach speed Testing in wind tunnel State of the art design facility Specific materials are needed 6/17/2015NASA Grant URC NCC NNX08BA44A

Supersonic mixing Ignition and flame holding are a first order issue for supersonic combustion 6/17/2015NASA 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 6/17/2015

NASA Grant URC NCC NNX08BA44A Combustion Turbulent Shear Mixing Density correct expression for shear layer growth including compressibility effects 6/17/2015

NASA Grant URC NCC NNX08BA44A Combustion Turbulent Shear Mixing Only applies to box cowl 6/17/2015

Flame Holder Using a cavity to develop a flame holder – reduces incoming supersonic velocity – It re-circulate the incoming air with fuel to increase mixture efficiency and promote combustion – A angled cavity allows the flow to reattach itself to the main flow with minimal turbulence and reduce drag – There two type of cavities open and closed 6/17/2015NASA Grant URC NCC NNX08BA44A

Cavity Flame Holder Open cavity – Is when the L/D is less than 10 – If the L/D is less than 2 the cavity will have transverse mechanism for wave oscillations – If the L/D is between 3-7 the cavity will have longitudinal mechanism for wave oscillations 6/17/2015NASA Grant URC NCC NNX08BA44A

Cavity Flame Holder Closed cavity – Is when L/D is greater than 10 – The flow does not separate from the incoming supersonic flow 6/17/2015NASA Grant URC NCC NNX08BA44A

Mach 2 Prototype Design Current design effort represent 4.5 mach design Lower mach speed Initial setup to test supersonic combustion stability Proof of concept Economical Simple in design 6/17/2015NASA Grant URC NCC NNX08BA44A

Mach 2 Design 6/17/2015NASA Grant URC NCC NNX08BA44A Lab Supply Quick Release – CD Nozzle Connection Section View Converging Diverging Nozzle Drawing

Mach 2 Design 6/17/2015NASA Grant URC NCC NNX08BA44A Lab Supply Quick Release – CD Nozzle Connection

Mach 2 Design 6/17/2015NASA Grant URC NCC NNX08BA44A Lab Supply Quick Release – CD Nozzle Connection Section View Fuel inlet

Converging Diverging Nozzle Using a converging diverging nozzle to produce mach 2.4 using 120 psi lab air The CD nozzle was designed using one dimensional isentropic flow of perfect gas 6/17/2015NASA Grant URC NCC NNX08BA44A This ratio is adjustable with a air regulator

CD Nozzle C/D Nozzle drawing 6/17/2015NASA Grant URC NCC NNX08BA44A

CD Nozzle Calculations 6/17/2015NASA Grant URC NCC NNX08BA44A Expansion Area Ratio Throat Compression Area Ratio Expansion Area Ratio Throat Area Expansion Area Ratio A A M = 2.4 Isentropic flow properties D=.30D= Throat D=.13

C/D Simulation Virginia Tech applet 6/17/2015NASA Grant URC NCC NNX08BA44A

6/17/2015NASA Grant URC NCC NNX08BA44A Cavity Flame Holder The ratio of Length vs. Depth is very critical in design The goal is to obtain the best L/D ratio to the incoming Mach number L/D ratio for our cavity 4.7 It is also has a back angle of 17.2° 1.65 in Length.354 in Depth 17.2 °

Cavity Flame Holder 6/17/2015NASA Grant URC NCC NNX08BA44A Dual cavity design

COSMOS Flowork 6/17/2015NASA Grant URC NCC NNX08BA44A Mach number results for our cavity design

COSMOS Flowork 6/17/2015NASA Grant URC NCC NNX08BA44A Velocity profile results for our cavity design

Combustion Chamber 6/17/2015NASA Grant URC NCC NNX08BA44A Cavity design L/D ratio 4.7 Reduction of choke flow Exhaust is larger diameter Fuel Injection locations Four Ports Spark plug locations one in each cavity Fuel inlet

Ignition System Car Distributor Car Battery Ignition Box Drill motor Rim Fire Spark Plug 6/17/2015NASA Grant URC NCC NNX08BA44A

Materials Aluminum 6061 Currently used in prototype fabrication Copper Steel Stainless Steel 304 High Nickel Steels 6/17/2015NASA Grant URC NCC NNX08BA44A Aluminum 6061 Stock Material

Fuel Hydrogen – Primary Fuel – X-43 – High energy density – Clean burning Water is the primary combustion bi-product No x is possible bi-product of high temperature fuel and air dissociation Ethylene – X-51 initial fuel JP-10 Fuel – Alternative Primary Fuel – X-51 6/17/2015NASA Grant URC NCC NNX08BA44A

Current Progress 6/17/2015NASA Grant URC NCC NNX08BA44A Manufactured supersonic combustion chamber

Current Progress 6/17/2015NASA Grant URC NCC NNX08BA44A Manufactured supersonic combustion chamber

Current Progress Spark plugs Rim Fire VR2L Order and will ship out 7/26/2010 6/17/2015NASA Grant URC NCC NNX08BA44A

Current Progress 6/17/2015 NASA Grant URC NCC NNX08BA44A Distributor Ignition Module Coil Car Battery All have been Purchased

Proof of Concept Sustain supersonic combustion – Increase mixing, sustain flame, prevent blow out Design Component Parameterization – Supersonic leading edges – Flame Holders - Cavity L/D Ratios – Ignition Type & Location » Located according to necessary mixing length Develop and simulate computational fluid dynamics analysisof overall design and individual components Compare and analyze test data – Develop correlations Achieve supersonic combustion throughout the engine 6/17/2015NASA Grant URC NCC NNX08BA44A

Future Work Develop a COMOS flowork analysis of C/D nozzle Develop a mathematical model of longitudinal oscillations in cavity Have C/D nozzle machined Prandtl-Meyer expansion exhaust Combustion Stability 6/17/2015NASA Grant URC NCC NNX08BA44A

Cost Analysis 6/17/2015NASA Grant URC NCC NNX08BA44A Totals $1000$5500$7,250

Timeline Hypersonic 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 Cavity Development Begin research on Thesis Development Fuel SelectionPresentation Begin research on fuel igniter locator Began Research on diffuser exhaust Presentation Dr. Spanos Presentation Supersonic Diffusuer Initial Design Angle Determination of Diffuser Shear stress in compressible & non compressible flow Determine Shear Layer in compressible & non compressible flow Machining of New CD Nozzle 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 Math Model for cavity oscillations 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 Cavity Development 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 Selection Machining of New CD Nozzle 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 Cosmos Flowork for CD nozzle 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 6/17/2015NASA Grant URC NCC NNX08BA44A

6/17/2015NASA 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”.

6/17/2015NASA 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 2007.

6/17/2015NASA 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 Alonzo Perez Dr. P. Spanos, Rice University Johanna Lopez

Questions 6/17/2015NASA Grant URC NCC NNX08BA44A