Combustion Team Faculty Advisors: Dr. Guillaume Dr. Wu Dr. Boussalis Dr. Liu Sara Esparza Cesar...

Combustion Team

Faculty Advisors:

Dr. GuillaumeDr. GuillaumeDr. Wu Dr. Wu Dr. BoussalisDr. BoussalisDr. LiuDr. 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


Governing Equations:Motion of Fluid Substances

• Conservation of Mass

fTpDt

Dv

0 vDt

D

pRT

WdUQ

SJxumxMt

)(

1

)(

1

)(

1

• Conservation of Momentum

• State Equation – Ideal Gas Law

• Conservation of Species

• Conservation of Energy


Combustion

Combustion stoichiometryIdeal fuel/ air ratio

Recommended fuels for scramjetsHydrogen - most common EthyleneKerosene

Only oxidizer is airIn scramjets, combustion is often unstableEquivalence ratio

Should range from 0.2 - 2.0 for combustion to occur with a useful time scale Lean mixture ratio below 1.0Rich mixture ratio above 1.0

tricstoichiome

actual

AF

AF


Equivalence and Swirl Ratios:Specific to Combustion Projects

0H2

yN

476.3xCO3.76NO

4HC 22222yx

yx

yx

• Equivalence Ratio, φ

axial

tagential

G

GS

• Swirl Number, S


Supersonic Combustion


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


Speed of Sound

TRa

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


Mach Number & Operational Regimes – Subsonic, Transonic, Supersonic & Hypersonic Flight

SubsonicBoeing 747

0<Ma<1Ma =.85

SupersonicF15 Fighter Plane

1.0<Ma<3.0Ma =1.5

HypersonicSpace Shuttle

Ma>3Ma =25


Reversed Alligator Inlet Design Chosen

Multiple Inward Turning Scoop Reversed Inlet Design Chosen


CompressorTurn Angle 18deg

Variable CowlMach decrease from heat input

DiffuserExit angle12.29 deg

Integrated Scramjet Vehicle


Exit Mach Number One Dimensional Flow


Shockwaves Traverse through Engine Two-Dimensional Flow


Shock and Turn Angles


Prandtl Meyer Expansion Waves


Integrated Scramjet Vehicle

M∞ = 4.5

M = 2.6

M = 2.1

M = 4.2


Supersonic mixing

Ignition and flame holding are a first order issue for supersonic combustion


Supersonic Combustion – Mixing & Stability

Supersonic Mixing

Development of mixing length

Development of injector location

Development of ignition location

Development of flame holder


CombustionTurbulent Shear Mixing


Turbulent mixing at supersonics speeds

Micro-mixing



• Mean velocity profile combines– Prandtl’s number

– Turbulent kinematic viscosity

– Time average characteristics of turbulent shear

3

431

11

yy

r

r

U

U

c

Micro-mixingFuel vortexFuel wave



Shear layer width – Two methods

m

m

lB

xr

rB

1

16 2

Local shear layer width for turbulent shear mixing

xr

rCm

1

1

Recent researchCδ is a experimental constant



• 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

2

1

2

12

1

21

22

11

2222

2111

2

1

2

1

2

1

UU

UU

U

Us

PP

UUU

UUU

uPuP

s

c

c

c

c



• Convective velocity for the vortex structures

• With compressible flow using isentropic stagnation density equation changes to

2

22

1

11

1222

212

11

2/12

2/11

2

1

1

2

11

2

11

1

a

UUM

a

UUM

MM

s

UsUU

cC

cC

CC

c



• Density correct expression for shear layer growth including compressibility effects

213

1

2/1

2/1

2/1

2/11

8.2.)(

1129.1

1

11

12

1

1

1)(49.

cMc

cm

eMf

rr

rsrs

rs

rs

rCMf

x




Supersonic Mixing Efficiency

• Mixing Efficiency

1,179.0 072.1 0 eC

b

Lmm

F

1,333.3 0204.1 0 eC

b

Lmm

A


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


Combustion Stability

Flame velocity

Flame length

Recirculation

Detonation

Auto-ignition

Back pressure


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


Combustion Performance & Design

Detonation – shockwave induced combustion

Flame holder – use back pressure to control flame stability

COSMOSWorks Flame Holder Inlet Mach 4.5Velocity contours shows recirculation zones


Injector Pressure Profile


Fuel Injector Holds the Flame


Size Coolant Delivery Mechanism according to

Pressure and Temperature

Pc Mechanism

700 tubes

1310 tubes

1378 channels/tubes

1486 channels/ablative

2994 channels/tubes


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


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


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”.


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”. 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” 4 th 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.


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


Timeline2009 - 2010


Timeline2010 - 2011

2011 Timeline Excel

Supersonic Combustion Team Timeline: March 2010 - February 2011

2010 2011Student Name MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB

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 adjustableDetermined 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



time

Developed cost to

determined Budget

First cavity is adjustableDetermined if Budget can be

obtained

Alonzo Perez Engineering Drawing of Flame Holde

Attempt Supersonic

Combustion

Gather Data

Attempt Multiple

combustion Chamber



time


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Combustion Team Faculty Advisors: Dr. Guillaume Dr. Wu Dr. Boussalis Dr. Liu Sara Esparza Cesar...

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