Combustion mbustion Eng ngine ine us using ng STAR AR-CD CD - - PowerPoint PPT Presentation

Overvie view w & Perspecti spectives es for Inter ernal al Combustion mbustion Eng ngine ine us using ng STAR AR-CD CD

Marc ZELLA LAT

Quick ck overvie iew w of ECF CFM M fa famil ily y models ls Examples xamples of validat dation ion for Diesel and d SI-GDI GDI engines ines Intr trod

• duc

ucti tion

• n to multi

ti-com componen

• nent

t fuels Applicati ication

• n and

d validat dation

• n of multi

ti-comp component

• nent fuel to SI-GDI

GDI and d Dual al fuel engines ines

– Real multi-component gasoline – Influence of anti-knock additive in the fuel mixture – Dual fuel : Diesel/Natural gas combustion

Conclus clusion

• n and

d perspectiv ectives es

TOPICS PICS

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

A General ral Schemati ematic c View of Spray y and Combust mbustio ion n

• c
• Z

st

• Diffusion reaction zone
• Air
• mixture
• Demoulin & Borghi,

Comb.Flame,129(2002)

• Large scales : τ=k/ε

(integral lenght )

• Small scales : τ=(ν/ε)**0.5

(Kolmogorov lenght)

Mixtur ure e fluctuations uations Temperat eratur ure e fluctuat uations ions Auto-Igni Ignitio ion Post-ox

• xidat

idation ion Temperat eratur ure e fluctuations uations Mixtur ure e fluctuations uations Kinet etic ic controll rolled ed

air + egr fuel

spray

air + egr fuel mixed

spray

air + egr fuel mixed

spray

fuel injection into charge (air + egr) mixing of fuel and charge ignition in mixed zone

air + egr fuel mixed

spray

unburnt burnt Combustion in mixed zone

+ Un-mixed in burnt gases

‘EXTENDED COHERENT FLAME - 3 3 ZONE’ possible fluid states in computational cell

time

THOE OERETICA RETICAL L ECFM-CLEH CLEH MODEL EL DESCR SCRIP IPTION TION: : ECFM FM-3Z 3Z / ECFM FM-CLEH LEH models els : : conceptu ptual al frame mewor

• rk
• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

PSTOX F DIFF F PM F UM F F

Z Z Z Y Z    

ECFM-3Z 3Z Zf/unmixed

Zf/premixed Zf/diffusion

Transfer fer is function tion of c only Transfer fert if Phi > Phi.cr i.crit it. The diffus usion

• n zone

ne is unmixed ixed burnt nt gases es The post-ox

• xidat

idation ion is mixed ed burnt t gases es The trans nsfer er between een zones nes is from turbulent ulent mixing ing and the combus bustion tion progr gres esses es

Spray

ECFM-CL CLEH EH

THOE OERETICA RETICAL L ECFM-CLEH CLEH MODEL EL DESCR SCRIPTION IPTION: : ECFM FM-3Z 3Z / ECFM FM-CLEH LEH concept pt : Flame

lame str tructure cture

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

THOE OERE RETIC TICAL AL ECFM-CLEH CLEH MODEL EL DESC SCRIP IPTION: TION:

ECFM-CLEH CLEH model : Fundame ndament ntal al appr proac ach h of 4 reactio ion n rates

Propagation Diffusion flame G F G B Auto-ignition ECFM model Mixing PDF model P.D.F : Mixture Fraction FLUCTUATION TKI-PDF model

AI-Saturation Coupling

Ox fuel

Tables bles for r LFS Flame surface density ITNFS Function

Mixing controlled reaction rate Distributed flame with Pdf on mixing scalar (look-up table)

Post-Oxidation Chemical Kinetics

Chemistry controlled reaction rate NO Fluctuations

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

5 operating conditions

poin int 1 : F : Full ll lo load poin int 2 : Mid Mid-load load poin int 3 : M : Mid id-load load poin int 4 : L : Low-load load poin int 5 : L Low-load load Swir irl l Leve vel l : Fla lap open/closed en/closed

Autom

• motiv

tive e DIES ESEL EL ENGIN GINE E B : RES ESULTS TS

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

Emissions NOx-NORA NORA S SOOT OOT CO CO

10 20 30 40 50 60 70 80 90 100

1 2 3 4 5

Soot Experiments STAR-CD

10 20 30 40 50 60 70 80 90 100

1 2 3 4 5

CO Experiments STAR-CD

10 20 30 40 50 60 70 80 90 100

1 2 3 4 5

NOx Experiments STAR-CD (NORA)

Autom

• motiv

tive e DIES ESEL EL ENGIN GINE E B : RESU SULTS TS

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

112 146 116 80 172 141 79 20 10

50 100 150 200

• 4
• 2

2 4 CLEH EXPE

7 14 34 44 6 20 15 26 34 31

5 10 15 20 25 30 35 40 45 50

• 4
• 2

2 4 CLEH EXPE

Inje ject ctor

• r 1

Inje ject ctor

• r 2

SO SOOT Retarted Injection

Autom

• motiv

tive DIES ESEL EL ENGIN GINE E C : Inject ector

• r 1 v

versus sus Inject ector

• r 2

Inj nject ection n timing ming variati iation

• n comparison

arison : : SOOT

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

Injector 1 Injector 2

Soot Diameter Soot Diameter Distribution Distribution

The Soot Sectional Method is capable to differentiate Soot diameter and Distribution between injector 1 and injector 2

ENG NGINE INE C C : : Inj nject ector

• r 1 v

versus sus Inj nject ctor

• r 2

Injec ectio tion n timing ming variat iation ion comparis arison

• n :

SOOT T Section ctional al soot model el / PDF

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

GDI GDI-GASOLIN GASOLINE: : Real l Engine ngine Wall l Guided ed Multi ti-hole

• le inject

ector

• r

11

Spra ray y and d mix ixture ure @ 440 °CA ABDC Equival ivalenc ence ration ion aro round und TDC Red d is is a above

• ve ER 1.
• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

In In-cylin cylinder der pres ressur ure e his istory

• ry (left)

t) - Ap Appare parent nt Hear ar Rele leas ase e (right ight) Zoom

• m on : In

In-cylin cylinde der r Pres essur sure Apparen arent Rate e OF Heat at Releas lease

GDI GDI-GASOLIN GASOLINE: E: Real l Engine ngine Operat rating ing point nt 1 : : ECM-CLEH CLEH

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

A single le comp mpon

• nent

ent repres resen enta tativ tive e fuel has been used in the example amples and d validat dation

• ns shown

n in the previou

• us section
• n

SI SI-GDI GDI engines ines are e very y sensitiv tive e to the fuel compo mposition ition (evaporation

• ration process,

s, strat atifica icati tion

• n,

, Octa tane numb mber er calibra libration tion using g additiv tives es …) Dual al fuel combu bustion tion is emergin ging, g, especia cially ly in combination ination with Diesel and Natu tura ral gas To get et bet etter er simulation lation of the system m includ ludin ing combu busti tion

• n chamb

mber, fuel compo mpositi ition

• n and

d mixture ture preparati aration

• n strat

ategy gy CD CD-adapco dapco has extend ended ed existing ing combus ustion tion models in STAR AR-CD D to multi ti- compo mponent nent fuel.

Introdu

• duction

ction of Multi ti-com compone

• nent

nt fuel

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

Crud ude

• ïl

ïl

Light Fraction

Heavy Fractio tion

Lig ight ht Gaso soli line C5 – C6 C6 RON 60 - 80 80 Heavy vy Gaso soli line C7 – C10 RON 20 - 50 50 Unle leaded Gaso solin ine RON 95 - 98 98 MON 85 - 87 87

The refiner iner must st im imple lemen ment proces

• cesses

ses to to im improve rove the gasoline soline octan

ane number er from natura

ural crude rudes.

Boiling Temperature Heavy Gasoline Light t Gasol

• lin

ine

Aromatics Benzene Toluene

Gasoline

• line disti

tillati lation

• n problem

lem

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

Americ

rican an Society ty for Testing ting and nd Materials erials Cooperati perative e Fue uel Rese sear arch h : Distillation tillation process ess

% volume Temperature

ASTM procedure

Heated Multi-component Droplet

STAR-Simulation

% volume Temperature

C1 C1+C2 C1+C2+C3+ C4=anti-knock Agent

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

The e liqui uid is repres resent nted d us using g N compon ponen ents ts Vapor

• riza

izati tion

• n is treat

ated ed us using the e discre crete e approach ach For r comb mbusti ustion

• n:

– The molecular weight is computed according to local component concentration taking into account the number of C, H and O in each component – Same treatment for the Enthalpy of formation and Laminar Flame speed

For r Aut uto-Igni gniti tion

• n:
• 1. When correlation is used:
• Ignition delay and auto-ignition rate are balanced by the Octane (cetane) number of

each component

• 2. When tables are used:
• Tabulated Kinetic for Ignition technique is used, extracting information directly from

the tables

The mult lti-com

• mpon

ponen ent t approac

• ach

h with h ECFM FM-3Z 3Z combu bust stion ion model el

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

Gasoline represented by 4 components

Pressure :full cycle Pressure : zoom around TDC A.R.O.H.R :full cycle A.R.O.H.R : zoom around TDC

Experiment STAR-CD

SI SI-GD GDI I Wall l Guided ed : MULTI TI-COMPONENT COMPONENT COMBUS BUSTION TION

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

Comparison with baseline gasoline: Same amount of energy is introduced due lower L.HV for Ethanol

Pressure :full cycle A.R.O.H.R : zoom around TDC Gasoline 4C Combustion Laminar flame speed E85 Combustion

E85 – Combust bustion

• n

Bett etter er homog

• geni

enizati zation

• n

around und stoic

• ichiome

hiometr try Higher gher Lami minar nar Flame ame Speed eed for r Ethanol anol Higher I.M.E.P

MULTI TI-COMPONE COMPONENT T – E85 (Mixt ixture ure Ethanol/ hanol/Gasoline Gasoline)

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

SPRA RAY Y 40 40 CA after er star art t of injec ectio tion

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

4 4 compo mponents nents E85 (Gas asolin line e / Et Ethanol nol Mix ixture) ure)

Operating point 1 KNOCK : Spark Timing VARIATION Reduced Anti-knock Agent

Chemical Heat Release Total Chemical Heat Release Premixed Propagation Post-oxidation Premixed Auto-Ignition Diffusion

S.T=20 btdc Mean In-cylinder & Local sensor

S.T=13b 13btdc dc

GDI GDI-GASOLIN ASOLINE: E: Spra ray wall Guided ded

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

AI + PM iso-surfaces of Chemical Heat release

Chemical Heat Release Total Chemical Heat Release Premixed Propagation Post-oxidation Premixed Auto-Ignition Diffusion

Pr Premixe emixed d Pr Propaga

• pagation

ion Pr Premixe emixed d Au Auto-Ign gnitio ition

Stati atic c (728 °CA CA) ) Knock k onset t (spac pace e and time) me)

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

CFD Simulation ulations of a Dua ual Fue uel l Engine * Premix mixed ed Natural ural Gas (meth thane) ane) + Diesel sel Pilot

• t injecti

ection

• n

Tabulated Kinetic for Ignition is used for Auto-Ignition delay

and rate of Auto-ignited consumed fuel

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

*prepared by J.Lim

Case 1 NG % 2.20 Diesel [mg]

27.26

Case 2 NG % 1.72 Diesel [mg]

156.90

Experiment STAR-CD

Pressure essure Trac ace e – for case 1 a and 2

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

*prepared by J.Lim

Case 2 NG % 1.72 Diesel [mg]

156.90

Case 1 NG % 2.20 Diesel [mg]

27.26

Premixed Auto-Ignition Diffusion Propagation

Mixed Mode of Combustion Diesel Mode of Combustion

Chemical mical heat Release lease for case 1 a and 2

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat

*prepared by J.Lim

Single e compone

• nent

nt using ng a representa sentati tive e speci cie

– Well established in ECFM combustion models (ECFM-3Z and ECFM-CLEH) – Good level of prediction for pressure, heat release, wall heat fluxes – Good level of prediction in emissions : NO, CO and Soot – The soot sectional method is able to predict soot diameter and distribution

Emergence gence of multicom icompone ponent nt for mixtu ture e preparat atio ion n and combus mbustion

• n

– ECFM-3Z has been extended to multi-component fuel – Combustion and fuel composition are seen now as a system – Ethanol blended duel and Dual duel combustion has extensively been validated – Possibility to take into account the detailed mechanism – Introducing different fuel (via External tables) – CD-adapco is working to provide a tool for tables generation using DARS chemistry solver – ECFM-CLEH will extended to multi-component fuel in STAR-CD V4.22 (next release)

Conclusion and Perspectives

• G. Desoutter, A. Desportes, J. Hira, D. Abouri, M. Zellat