Panel Session: Observations Regarding Autoignition and ... › sites › default › files › event... · Panel Session: Observations Regarding Autoignition and Contributions of

Panel Session: Observations Regarding

Autoignition and Contributions of the

UTSR Program

Fred Dryer, Hong Im,

Vincent McDonell, Eric Petersen, Margaret Wooldridge

UTSR 2014 Workshop

West Lafayette, IN

21 October 2014

UTSR 2014 Panel Session on Autoignition

Ignition Delay

• Why of interest?

– If tmix > tign, premixing (and associated temperature/emissions

reduction) becomes a challenge for LPM systems

– Relative location of reaction zone

– Basic characteristic for kinetic mechanism validation

REACTION

[CO]

[NOx]

Better Mixing

Mixing

Time

Location?

FUEL FLEXIBILITY INFLUENCES ON PREMIXED

COMBUSTOR BLOWOUT, FLASHBACK, AUTOIGNITION, AND

STABILITY (2008). ASME J. of Engineering for Gas Turbines and

Power. Vol. 130, January, pp. 011506-1 – 011506-10 (T. Lieuwen,

V. McDonell, E. Petersen, and D. Santavicca)

2/20


Ignition Delay

• Typical Ignition Delay Plot

– Log scale for Ignition Delay Time vs 1000/T (1/K)

• Exponential dependency on T

– Hydrogen behavior quite distinct from methane

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4

1000/T (1/K)

Ig

nit

ion

Dela

y T

ime

H2, Φ=1.0

H2, Φ=0.8

H2, Φ= 0.6

H2, Φ=0.5

NG, Φ=1.0

NG, Φ=0.510 µs

1 ms

1 s

100 µs

10 ms

100 ms

925104011751340154017902110

Temperature (F)

Comparison

of NG and H2

at 15 atm

RT

EATk n exp

]][[..

R.R.

1~DelayIgnition

OFkRR

3/20

Autoignition Devices

Devices:

• Shock tube – compress homogenous mixture with shock wave

• Rapid Compression Machine – compress homogenous mixture with piston

• Flow reactor – inject fuel into high temperature air stream and rapidly mix

• Each device has relative advantages/disadvantages along with different range of

operating conditions

P T Test Times

Shock tubes 1- 100 atm 1000 to 3000K < 10 ms

RCMs 1- 50 atm 900 to 1200K 1 to 50 ms

Flow Reactors 1 - 30 atm 300 to 1000K 50 to 500 ms

UTSR 2014 Panel Session on Autoignition 4/20

Gas Turbine Context

1 atm

700K 800K 900K 1000K 1100K 1200K

10 atm

Lefebvre et al.

(1980’s)

Flow Reactor

Flow Reactor

Pure Fuels/

Blends

UCI, UTRC

Princeton

Shock Tubes

Pure Fuels

+

Blends

RCMs

Pure Fuels

+

Blends

Temperature

Pre

ssure

e.g., Spadaccini &

Colket (1990’s)

Stanford

Petersen &

coworkers (2000s till

present)

e.g., Curran &

coworkers

(2000s, current);

Wooldridge

(current)

Lean Premixed Combustors (Simple/Recuperated) Reheat Combustors

15 atm

Holton et al. ‘09 (Blends)


Panel Session: Autoignition and UTSR

Flow Reactor Perspective

Vincent McDonell

UTSR 2014 Workshops

West Lafayette, IN

21 October 2014

UCICL Flow Reactor


Steady Flow Technique for Hydrogen

• Conditions for Ignition slowly approached

– Method of Spadaccini (1976) and co-workers at UTRC

– Small step increases in inlet T until ignition observed

– Ignition occurs at end of reactor as that point will have longest

time


Lreactor

U

Photodiodestign = L/U

• Other more efficient/effective methods developed and used

for later alkane studies

8/20


Experimental Results for Hydrogen

Boleda et al. (1999)—UCI EPRI Report

Beerer et al (2006)—UCI UTSR Final Report 03-01-SR112

9/20



Peschke, W.T. and Spadaccini, L.J. (1985) Determination of Autoignition and Flame Speed

Characteristics of Coal Gases Having Medium Heating Values. Final Report for AP-

4291 Research Project 2357-1

10/20


Results for Hydrogen vs Models

Mueller, M.A., Kim, T.J., Yetter, R.A., and Dryer, F.L. (1999a) Flow reactor studies and

kinetic modeling of the H2=O2 reaction. Inter. J. Chem. Kinetics, 31, 113

11/20


0.01

0.1

1

10

100

1000

0.8 1.0 1.2 1.4 1.6

Ign

itio

n D

ela

y (m

sec)

1000/T (1/K)

Current Study (6 atm) Φ=0.2-0.5

Peschke et al. (12-23 atm) Φ=0.3-0.6

Santoro et al. (9 atm) Φ=1.0

Snyder (1.0 atm) Φ=0.5




Wang (4 atm) Φ=0.6

Blumenthal (4 atm) Φ=0.6

Slack (2 atm) Φ=0.5

1250 1000 833 714 625Temperature (K)


Shock Tubes

Flow Reactor

12/20



0.00001

0.0001

0.001

0.01

0.1

1

10

0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Ign

itio

n D

ela

y (

se

c)

O'Conaire (20 atm) Φ=0.5O'Conaire (15 atm) Φ=0.5O'Conaire (6.5 atm) Φ=0.5O'Conaire (4 atm) Φ=0.5O'Conaire (2 atm) Φ=0.5O'Conaire (1 atm) Φ=0.5Peschke et al. (12-23 atm) Φ=0.3-0.6Snyder (1.0 atm) Φ=0.5Snyder (2.1 atm) Φ=0.5Snyder (4.2 atm) Φ=0.5Snyder (6.8 atm) Φ=0.5Wang (4 atm) Φ=0.6Blumenthal (4 atm) Φ=0.6Slack (2 atm) Φ=0.5Current Study (6 atm) Φ=0.2-0.5

11801340 1040 925 8251540

D.J. Beerer and V.G. McDonell (2008). AUTOIGNITION OF HYDROGEN AND

AIR IN A CONTINUOUS FLOW REACTOR WITH APPLICATION TO LEAN

PREMIXED COMBUSTION (2008). ASME J. Engr. Gas Turbines and Power,

Vol 130, 051507-1 to 051507-9, September.

• All mechanisms effectively same

• 1985 data--100x faster ignition 1000/T (1/K)

Temperature (K)

13/20



0.00001

0.0001

0.001

0.01

0.1

1

10

0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Ign

itio

n D

ela

y (

se

c)

O'Conaire (20 atm) Φ=0.5O'Conaire (15 atm) Φ=0.5O'Conaire (6.5 atm) Φ=0.5O'Conaire (4 atm) Φ=0.5O'Conaire (2 atm) Φ=0.5O'Conaire (1 atm) Φ=0.5Peschke et al. (12-23 atm) Φ=0.3-0.6Snyder (1.0 atm) Φ=0.5Snyder (2.1 atm) Φ=0.5Snyder (4.2 atm) Φ=0.5Snyder (6.8 atm) Φ=0.5Wang (4 atm) Φ=0.6Blumenthal (4 atm) Φ=0.6Slack (2 atm) Φ=0.5Current Study (6 atm) Φ=0.2-0.5

11801340 1040 925 8251540

1000/T (1/K)

Temperature (K)

Simple Cycle Reheat Cycle

Premixer

Conditions

14/20


Ignition Delay

• Engine Implications

H2/CO H2/CO CH4 CH4

Engine Pressure Air Temp Based on CHEMKIN Global Exp. CHEMKIN

(atm) (K) Experiments (Mueller) (Li&Williams) GRIMech

GE 9H * 23 705 85 11800 2336 21520

Solar Taurus 65 15 670 153 - 8713 -

Solar Taurus 60 12.3 644 221 - 21985 -

Solar Mercury 50** 9.9 880 59 4941 189 11660

GE LM6000 * 35 798 35 34850 214 15510

Siemens V-94.3A * 17.7 665 141 - 8448 -

Siemens V-94.2 * 12 600 336 - 88406 -

Capstone C60** 4.2 833 140 1869 917 6937

* Inlet temp estimated from ideal gas, isentropic compression

** Recuperated Engine

- represents no ignition within 1 min.

Estimated Ignition Delay Time, msEstimated Ignition Delay Time

What about wall surface effects, radiation, poor aerodynamics?

(ignition at 800K with 1/8” rod inserted into flow vs 1000K w/o)

Part load conditions D.J. Beerer and V.G. McDonell (2008). AUTOIGNITION OF HYDROGEN AND



Vol 130, 051507-1 to 051507-9, September. 15/20


0.01

0.1

1

10

1.2 1.25 1.3 1.35 1.4 1.45 1.5

Ign

itio

n D

ela

y (

sec)

1000/T (1/K)

Temperature (F)

Full ignition observed

Small temp. rise observed

Temperature drop observed

900940 860 820 7801000





Vol 130, 051507-1 to 051507-9, September.

Range still

well below

calculated

values

16/20


0.001

0.01

0.1

1

10

600 700 800 900 1000 1100 1200

Pre

ssu

re (atm

)

Temperature (K)

Explosive Limits

Extended 2nd Limit

Peschke '85 (12-23 atm)

Wang '03 (4 atm)

Blumenthal '69 (4 atm)

Snyder '65 (4.2 atm)



Current Study

1.54 0.830.860.900.951.001.051.131.211.291.40

1000/T (1/K)

"Strong" Ignition

"Mild" Ignition

Steady Reaction





Vol 130, 051507-1 to 051507-9, September. 17/20


Ignition Delay

• Reasons for Discrepancy?

– Flowing gas/wall effects shorten delay time?

• Noted by some (most GT premixers have flowing gas/walls)

– Homogeneous ignition vs “localized”?

Meyer & Oppenheim, 1971

“Mild” Ignition “Strong Ignition”

18/20

Flow Reactor Homogeneity

• Regions in the reactor are clearly not fully homogeneous

with respect to mixing/velocity……

• …..but are representative of the processes/rates within

practical devices


Plug flow validPlug flow invalid

Venturi/Mixing Region Constant Area Test Section

19/20

Alkane Behavior

• What about results for alkanes?

– Unlike H2, model/measurements agree well in low T region

(at least for this study)


10

100

1,000

1.05 1.10 1.15 1.20 1.25

Ign

itio

n D

elay

Tim

e (m

sec)

1000/Tmix (1/K)

This Study - Methane

This Study - Ethane

This Study- Propane

Galway - Methane

Galway - Ethane

Galway - Propane

910 K 870 K 830 K

D.J. Beerer and V.G. McDonell (2011). AN EXPERIMENTAL AND KINETIC STUDY OF

ALKANE AUTOIGNITION AT HIGH PRESSURES AND INTERMEDIATE

TEMPERATURES. Proceedings of the Combustion Institute, Vol 33, pp. 301-307.

9 atm

f = 0.6

20/20

Documents

Panel Session: Observations Regarding Autoignition and ... › sites › default › files › event... · Panel Session: Observations Regarding Autoignition and Contributions of