33 years and 27 days of Shock Tube Research at Stanford

D. F. Davidson, R. K. Hansonand Endless Graduate Students

Mechanical Engineering Department, Stanford University

Academic Genealogy (English & Irish)

• Lord Raleigh, Cambridge University (1842-1919) All Things Classical

• J. J. Thomson, Cambridge University (1856-1940) Electron

• Ernest Rutherford, Cambridge University (1871-1937) Nucleus

• Karl Emeleus, Queens University Belfast (1901-1989) Ionized Gases

• Robert Sloane, Queens University Belfast Langmuir Probes

• Robert Hobson, York University Toronto Canada Shock Tubes/Ion Kinetics

→ David F. Davidson, Ph.D. Physics (May 1986) NO++e-N*+O*

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Academic Genealogy (German & American)

• Heinrich Magnus, University of Berlin (1802-1870)• Gustav Wiedeman, Liepzig University (1826-1899)• August Foeppl, Technische Hochschule Munich (1854-1924)• Ludwig Prandtl, University of Gottingen (1875-1953)• Theodore von Karman, University of Gottingen (1881-1963)• Hans Liepmann, California Institute Technology (1914-2009)• Donald Baganoff, Stanford University (1932-2004)• Ronald K. Hanson, Stanford University

→ David F. Davidson, Sr. Research Scientist

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NASA STKinetics

Shock Tube 1

Ron Hanson

KSTKineticsShock Tube 2Matt Oehlschlaeger

Stanford Shock Tube Facilities

FASTFlexible ApplicationShock TubeHelsley/Wang

HPSTHighPressureShock TubeEric Petersen

ASTMulti-Purpose

Shock TubeRossman/Hanson/Haylett 4

In the Past:UTRC Shock Tube: lost in storage3x3 Imaging Shock Tube: lost alsoYork University 2” Glass Shock TubeUTIAS Hypersonic Tunnels

Stanford Shock Tube & Laser Facilities

431, 440 nmRing Dye Laser

2.7 & 4.3 µm Lasers

10.5 µmCO2 Gas Lasers

216 nmTi:Sapphire Laser 3.39 µm He-Ne Laser

UV/Vis/IREmission

Detectors/Cameras

Incident Beam Detector

Transmitted Beam Detector

PressurePZT

P5T5

P2T2 VRS

ReflectedShock Wave

Advantages of Reflected Shock Wave Experiments• 1-D spatially-uniform chemical reactor, perfect for computer modeling!!!• Near-ideal constant V or constant P platform • Excellent control of T, P (to within 1%)• Well-defined kinetics time zero

CH3

CH, NCO

C2H4

T(t)

Fuel

CH4C2H2

i-C4H8C3H6

3.0-3.4 µm Lasers

11µm QC Laser

Advantages of CW Laser Diagnostics• Highly sensitive, quantitative, µs time resolution• Access to many species and temperature

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InfraredH2OCO2T(t)CH4CH2OCH3CHOCONOCH3OHC2H4iC4H8

2.5 µm2.7 or 4.3 µm2.7 + 4.3 µm3.4 µm3.4 µm

3.4 µm 4.6 µm5.2 µm9.6 µm10.5 µm11.3 µm

UltravioletCH3NOO2HO2H2O2OHNH

Ultra-fast lasers used to extend UV tuning range (2009)

First use of tunable dye lasers in shock tubes (1982)

New lasers allow simple access to mid-IR (2007-Present)

216 nm225 nm227 nm230 nm230 nm306 nm336 nm

388 nm431 nm440 nm472 nm597 nm 614 nm670 nm

VisibleCNCHNCONO2NH2HCOO2

Species time-histories critical to modeling combustion k inetics!

M2 laser (2016) Ti:sapphire laser

replaces dye lasers 6

Stanford Laser Diagnostics

• Combustion* occurs through species* following multiple paths with hundreds of individual steps*

• So in shock tubes wemeasure those 3 things!!

- * Ignition Delay Times- * Species Time-Histories- * Fundamental Rxn. Rate Constants

How Do We Study Combustion Kinetics?

Warnatz/Heghes (2006)

Carbon Flow Diagram: Rich CH4/Air Flame

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Leonardo Da Vinci“Ginevra de Benci”c. 1474 National Gallery of ArtWashington DC

Next: The Classical ST Stuff

Early Years: 1986-1992 (Carbon # 1-3)• David Masten (GM) H+O2=OH+O• Anthony Dean (GE) CH Spectroscopy, AB+C=A+BC for H/C/O• Prof. John Mertens (Trinity) HNCO Kinetics• Albert Chang (JPL) NO Spectroscopy, UV Scanning• Brian McMillin (Lam) PLIF Imaging• Prof. Margaret & Steve Wooldridge (Ford) CN & OH Kinetics, Vis/UV lasers• Michael DiRosa (Los Alamos) NO Spectroscopy, CH3• Larry Zelson (Praxair) C2H4 Pyrolysis• Prof. Katharina Kohse-Hoinghaus NH2 Spectroscopy• David Davidson Photolysis, NH3, N-ARAS, CH4 Kinetics

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H + O2 OH + O Most Important Reaction in Hydrocarbon Oxidation

0.3 0.5 0.7 0.91010

1011

1012

1013

OH Laser Abs. Wang et al. (2017)

H2O Laser Abs. Hong et al. (2009)

H ARAS. Pirraglia et al. (1989)

2000K

k 1 [cm

3 mol

-1s-1

]

1000/T [1/K]

1428K 1111K

OH Laser Abs. Masten et al. (1990)

Shock Tube and Laser Absorption Study of CH2O Oxidation via Simultaneous Measurements of OH and CO Shengkai Wang, David F. Davidson, Ronald K. HansonJ. Phys. Chem. A (2017)

Shock Tube Study of the Reaction of H + O2 = OH + O Using OH Laser AbsorptionDavid A. Masten, Ronald K. Hanson, Craig T. BowmanJ. Phys. Chem. (1990)

An Improved H2/O2 Mechanism Based on Recent Shock Tube/Laser Absorption MeasurementsZekai Hong, David F. Davidson, Ronald K. HansonProc. Comb. Inst. (2011)

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Internat. J. Chem. Kinetics (1990)

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NH3 NH2 NH/N2H4 NNH/N2H2 N2/H2

J. Quant. Spectrosc. Radiat. Transfer (1989)

1790K, 1.21atm1.81%H2O/Argon

2195K, 1.07atm1.0%NH3/Argon

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OH Generated by Photolysis NH2 Generated by Photolysis

Combustion and Flame (1990)O

Ato

m A

bsor

banc

e

2580K, 0.53 atm2000ppm NO212ppm H25ppm N2O3ppm N/O by γ

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Rembrandt H. v. Rijn“Self-Portrait”1661 Kenwood HouseLondon England

Next: We start to see what elsewe can do with the tools we have!

A little Later: 1992-2002 (Carbon # 4-7)

• Prof. Eric Petersen HPST CH4• German Post-docs Woiki, Votsmeier, Rohrig, FM Spectroscopy• Venu Nagali H2O Spectroscopy• John Herbon OH ∆Hf

• David Horning Liquid Fuels• Prof. Matt Oehlschlaeger CH3, Benzene• German Visitors Profs. Schulz, Friedrichs, Photolysis, FM

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Internat. J. Chem. Kinet. (2001)S. H. Bauer Issue

OH Concentration Time Histories in n-Alkane OxidationD. F. DAVIDSON, J. T. HERBON, D. C. HORNING, R. K. HANSON

1511K, 1.51 atm500ppm i-C8H18/0.63%O2/Ar

Shock Tube Measurement of Branched Alkane Ignition Times and OH Concentration Time HistoriesM. A. Oehlschlaeger, D. F. Davidson. J. T. Herbon, R. K. Hanson

Internat. J. Chem. Kinet. (2003)

Our New Advertising Strategy:Ignition Delay Times

Species Time-HistoriesReaction Rate Constants 16

Dots: Davis/LawDash: Ranzi et al.*Dot-Dash: Curran et al.Dot-Dot-Dash: Pitsch et al.

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J. Quant. Spectrosc. Radiat. Trans. (1993)

Ethane Pyrolysis (1995)CH3 UV Absorption Spectrum

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Edgar Degas“Women Ironing”1884 Musee D’OrsayParis France

Next: We move to the real world where liquids are involved!

DFD Over 50: 2002-2010 (Carbon # 8-12)• Ben Gauthier Gasoline IDT• Venky Vasudevan DOE Formaldehyde Kinetics• Tom Hanson Aerosol ST• Will Heltsley Expansion Tube• Zekai Hong H2/O2 Kinetics• Prof. Subith Vasu Jet Fuel• Robert Cook Hydrazine• Genny Pang OH+Alkanes• Daniel Haylett Diesel on AST• Megan MacDonald RP-1• Zack Owens Reactive Chemkin• Prof. Jon Yoo Toluene PLIF

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Methyl concentration time-histories during iso-octane & n-heptane oxidation

D. F. Davidson, M. A Oehlschlaeger, R. K. HansonProceedings of Combustion Institute (2007)

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Iso-Octane/O2/Argon IgnitionIso-Octane/O2/Argon Ignition

Davis/Law 1998Ogink/Golovichev 2001Pitsch et al. 1996

Shock tube determination of ignition delay times in full-blend and surrogate fuel mixtures

B. M. Gauthier, D. F. Davidson, R. K. Hanson Combustion and Flame (2004) {cited 545x}

21IDT Peak scales as P-1.64

OH and C2H4 species time-histories during hexadecane and diesel ignitionD. R. Haylett, R. D. Cook, D. F. Davidson, R. K. Hanson Proceeding of Combustion Institute (2011)

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Diesel & C16 Ignition Delay Times C16H34 Speciation

First gas-phase IDT and speciation for C16/Diesel fuel on the Aerosol ST

100μ

s15

0μs

200μ

s

Reflected shockEndwall

Shock Flow Conditions:T1=296K, T2=498K, T5=696KP1=32torr, P2=0.25atm, P5=1.05atmXf=8% Tol/N2 Incident Vs=710m/s

498K 696K

Planar laser-induced fluorescence imaging in shock tube flowsJ. Yoo, D. Mitchell, D. F. Davidson, R. K. Hanson

First toluene PLIF images of shock bifurcation: shows interaction of reflected shock wave with boundary layer

Calculation of temperature field is not straightforward: PLIF signal related to T, P, XToluene

Images provide experimental data for CFD shock interaction validation

4 cm

Experiments in Fluid (2010)

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“Vincent Van Gogh”Self-Portrait with Bandaged Ear1889The Courtauld Gallery London England

Next: It’s still a struggle to get funding, even when we are doing exciting new things

DFD Over 60: 2012-Present (Carbon # 12-20)• Matthew Campbell AST heavy fuels• Brian Lam Ketones• Ivo Stranic Isotopic studies• Prof. Wei Ren C2H4 Spectroscopy• Prof. Aamir Farooq ST Temperature• Sieji Li Nitrogen Chemistry• Shengkai Wang All Sorts of Laser Stuff• Yangye Zhu Jet Fuels• Prof. Mitch Spearrin iC4H8• Marcel Nations O* kinetics• JK Shao HyChem

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Multi-species time-history measurements during n-dodecane oxidationD. F. Davidson, Z. Hong, G. L. Pilla, A. Farooq, R. D. Cook, R. K. Hanson

• Implication: Separate time scales for pyrolysis and oxidation enables new approach (HyChem) for modeling HC fuels!

• 5 species measured using laser absorption: fuel, OH, C2H4, H2O, CO2

• Data reveal separation of scales 10 µs: fuel pyrolysis 700 µs: stable intermediate oxidation 1 ms: ignition

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1410 K, 2.3 atm457 ppm C12H26/O2/Ar, φ = 1

Ignition

Fuel pyrolysisStable intermediateoxidation

Proceedings of the Combustion Institute (2011)

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AIAA (2019)

Jet-A Fuel (8 species) Highly Branched Fuel (6 species)

Pyrolysis products dominated by C2H4 Pyrolysis products dominated by i-C4H8

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Ignition delay time correlations for distillate fuelsD. F. Davidson, Y. Zhu, J. Shao, R. K. Hanson Fuel (2017)

12 atm, φ=1, air/airgon

Distillate Fuels:A- Jet FuelsR- Rocket PropellantsK- KerosenesD- DieselG- Gasoline

28It is nice when everything falls on one line!!

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Jackson Pollock“Lavender Mist: Number 1, 1950”National Gallery of Art Washington DC

Next: Doing ST stuff that has never been done before

New Shock Tube Stuff Developed by Our Students • High-pressure kinetics to 500+ atm, EOS measurements for Argon

Eric Petersen• Application of driver Inserts to achieve dP5/dt ~ 0

Zekai Hong• Extended drivers and tailored mixtures to achieved 100 ms test times

Matt Campbell/Adam Susa• Addition of CRV valve to enable constant P constraint operation

Matt Campbell/Adam Susa• Spatially-uniform aerosol generation to investigate gas-phase heavy fuels

Tom Hanson/Dan Haylett• Accurate (+/-5K) temperature measurement in ST using laser absorption

Aamir Farooq/Several Others• GC sampling and LA in real-time to access 1st stage NTC kinetics

Alison Ferris• Endwall imaging to identify inhomogeneous ignition events

JK Shao/Valerie Troutman30

DFD Shock Tube Summary

• Fundamental Kinetics Database Utilizing Shock Tube Measurements• Summarizes 33+ years of shock tube measurements in our lab• On line https://purl.Stanford.edu/kb621cw6967• 267 pages of IDT Tables• 71 pages of Speciation Citations• 200 Fundamental Reaction Rate Measurement Citations• Thanks to all the grad students, my Google H-Index = 58, 10K+ citations

with 350 co-authored publications, (of which I was forced to write 66 of them)

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What’s left to do?• Big Data: multi-wavelength/multi-species analysis of complex fuels• Spectroscopy: IR and UV absorption spectra at high temperatures• Ion/Electron Kinetics: apply new lasers to old problems• Commercialization: Use shock tubes for ASTM fuel testing• Temperature: Use T(t) to constrain heat release models for combustion• HO2+CH3: find a simple way to measure this rate (Hong 2012)• S and P: do for sulfur and other species what we did for C/H/N/O• NTC Kinetics: speciation studies before all cars become electric• RCMs: Convince the RCM people to use shock tubes instead

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Exotic Travel while at Stanford

• Morroco 1990 • Japan 1991 • Turkey 1995• China 1998• India 2002• Cambodia 2005• Vietnam 2007• Egypt 2009

• Tibet 2010• Indonesia 2011• Guatemala 2012• Burma 2013• Israel 2015 • Sikkim 2015• Korea 2016• Egypt 2017• Coming up: Indonesia 2019

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Angkor Wat

Hanoi

Cairo

Northern Ontario

Tibet

Tibet

Santa Cruz

LuangPrabang

Jerusalem

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Acknowledgements

Recent Staff: Drs. Rito Sur, Chris Strand, Shengkai Wang, Jiankun Shao, Jay JeffriesSome of our Sponsors: AFOSR, ARO, ONR, NASA, DOE, FAA, TOTAL, SHELL, NSF

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