ECN 3: Flame structure 1/19April 2014

Experimental analysis between Experimental analysis between LIF-OH/355 from IFPEN, SANDIA and TU/eLIF-OH/355 from IFPEN, SANDIA and TU/e

H. Baya Toda, M. Meijer, N. Maes, S. Skeen, L. Pickett, LM, Malbec, G. Bruneaux

Third Workshop of the Engine Combustion Network,

April 4-5, 2014, Ann Arbor, USA,

ECN 3: Flame structure 2/19April 2014

• Analyze the spray flame structure

• Assess the repeatability of measurements among different institutions

• Improve measurements/post-processing for more reliable results for next ECN meetings

Objectives

ECN 3: Flame structure 3/19April 2014

• Flame phases – spray A

• Operating conditions for comparisons

• Hardware comparisons

• 2D and 1D profiles comparisons

Contents

ECN 3: Flame structure 4/19April 2014

0 1000 2000 3000 4000 5000 6000 7000time [us]

0

10

20

30

40

50

60

70

80

90

100

110s[

mm

]

BBand(soot)

ShadowR

ShadowI

LOL-OH*

LOL(t)-BBand

Analysis of flame phases – Spray A

sR sinert

FTP

SOC

I II IIIEOI

LOL OH*

FL

Sources of information – Shadowgraphy (CMT)– OH* Chemiluminescence LOL OH* (CMT) – Broadband chemiluminescence

• FTP(t) = Flame Tip Penetration (CMT)• LOL(t) (Sandia)

LOL(t)

ECN 3: Flame structure 5/19April 2014

0 1000 2000 3000 4000 5000 6000 7000time [us]

0

10

20

30

40

50

60

70

80

90

100

110s[

mm

]

BBand(soot)

ShadowR

ShadowI

LOL-OH*

LOL(t)-BBand

Analysis of flame phases – Spray A

sR sinert

FTP

SOC

I II IIIEOI

LOL OH*

FL

LOL(t)

Combustion stages – (I) = Autoignition and early development

• From SOC until reacting penetration accelerates over inert case• The reacting spray undergoes a transition from inert to reacting flow

ECN 3: Flame structure 6/19April 2014

0 1000 2000 3000 4000 5000 6000 7000time [us]

0

10

20

30

40

50

60

70

80

90

100

110s[

mm

]

BBand(soot)

ShadowR

ShadowI

LOL-OH*

LOL(t)-BBand

Analysis of flame phases – Spray A

sR sinert

FTP

SOC

I II IIIEOI

LOL OH*

FL

LOL(t)

Combustion stages – (II) = Mature flame

• From the end of (I) until EOI• (IIA) Transient mature flame – LOL still unsteady (upto 2000 us)• (IIB) Quasi-steady mature flame – LOL steady but FTP increasing (upto 4000 us)• (IIC) Steady flame – FTP steady (FL)

ECN 3: Flame structure 7/19April 2014

0 1000 2000 3000 4000 5000 6000 7000time [us]

0

10

20

30

40

50

60

70

80

90

100

110s[

mm

]

BBand(soot)

ShadowR

ShadowI

LOL-OH*

LOL(t)-BBand

Analysis of flame phases – Spray A

sR sinert

FTP

SOC

I II IIIEOI

LOL OH*

FL

LOL(t)

Combustion stages – (III) = Burn-out phase

• From EOI onwards

ECN 3: Flame structure 8/19April 2014

Operating conditions for comparisons

Phases IFPEN SANDIA TU/e

PLIF-355 Transient 0.7 ms 0.7 ms X

Stabilized 2.7 ms 2.5 ms 4.7 ms*

PLIF-OH Transient 0.7 ms X 0.7 ms*

Stabilized 4.7 ms X 4.7 ms** Assuming an identical hydraulic delay as at IFPEN: 300us

0 1000 2000 3000 4000 5000 6000 7000time [us]

0

10

20

30

40

50

60

70

80

90

100

110

s[m

m]

BBand(soot)

ShadowR

ShadowI

LOL-OH*

LOL(t)-BBand

sR sinert

FTP

SOC

I II IIIEOI

LOL OH*

FL

LOL(t)

ECN 3: Flame structure 9/19April 2014

Hardware differences

IFPEN SANDIA TU/e

Injectors 201-02 370 201-01

PLIF-355 Laser sheet 55 mm 65 mm 90 mm

Energy 100 mJ 100 mJ 110 mJ

PLIF-OH Excitation line Q1(6) 282.920 Q1(9) 283.928

Energy 11-17 mJ 11 mJ

Laser sheet 40 mm* 30 mm

* Measurements were performed with two laser sheets

ECN 3: Flame structure 10/19April 2014

Flame structure – Spray A

Liquid phase

Formaldehyde

Hot burnt gases

PAH

Reaction zone

1. The formaldehyde structure decreases when increasing tempereature/ [O2]

2. The PLIF-OH signal start « almost » at LOL (OH*)

ECN 3: Flame structure 11/19April 2014

PLIF-355: 2D comparisons

Formaldehyde

PAH

ECN 3: Flame structure 12/19April 2014

PLIF-355: 2D comparisons IFPENSANDIA

ECN 3: Flame structure 13/19April 2014

PLIF-355: 2D comparisons

Formaldehyde

ECN 3: Flame structure 14/19April 2014

PLIF-OH: 2D comparisons t = 4.7 ms ASOI

ECN 3: Flame structure 15/19April 2014

Profiles comparison: PLIF-OH

ECN 3: Flame structure 16/19April 2014

PLIF-OH: 2D comparisons t = 0.7 ms ASOI

Not the same structure ?

•Laser profile correction ?

•Timing ?

•AI delay differences ?

Not the same penetration

•Ambient conditions ?

•Injector to injector variations ?

•Hydraulic delay ?

ECN 3: Flame structure 17/19April 2014

PLIF-OH: 2D comparisons t = 0.7 ms ASOI

0.4 ms 0.7 ms

4.7 ms 0.7 - 1 ms

ECN 3: Flame structure 18/19April 2014

Conclusions

• Good agreement for PLIF-355 measurments • Transient (IFPEN and SANDIA)• Steady phase (IFPEN,TU/e and SANDIA)

• Good agreement for PLIF-OH measurements at steady state phase

• PLIF-OH comparisons during transient phases are more difficult and need more time for investigation

• PLIF-OH from TU/e more suitable for LOL estimation because of the stable energy laser

ECN 3: Flame structure 19/19April 2014

Thank you to all the contributors and good luck to the CFD GUYS !