PROF SEUNG WOOK BAEK DEPARTMENT OF AEROSPACE …procom.kaist.ac.kr/Download/Combustion/Combustion 1.pdfK.K.Kuo, “Principles of Combustion,” Wiley V.R.Kuznetsoz and V.A.Sabelnikov,

COMBUSTION

PROF. SEUNG WOOK BAEK DEPARTMENT OF AEROSPACE ENGINEERING, KAIST, IN KOREA

ROOM: Building N7-2 #3304

TELEPHONE : 3714

Cellphone : 010 – 5302 - 5934

[email protected]

http://procom.kaist.ac.kr

TA : Hyunwook Jegal

ROOM: Building N7-2 #2311

[email protected]

TA : Kyu-Seop Kim

ROOM: Building N7-2 #1308-4

[email protected]

http://procom.kaist.ac.kr/

COURSE CODE : AE 410

COURSE NAME : COMBUSTION ENGINEERING

PROFESSOR : SEUNG WOOK BAEK (Rm #3304, Ext. 3714)

GRADING SYSTEM

1 Final Exam

Homeworks

SYLLABUS (1/4)

How to efficiently mix fuel and oxidizer

Convection and diffusion

How to efficiently burn fuel and oxidizer: energy saving

How to reduce pollutant emission such as CO,CO2 and NOx

How to improve safety and reduce impact on environment

To develop green, sustainable and alternative energy

CURRENT ISSUES IN COMBUSTION SCIENCE &

TECHNOLOGY

REFERENCES

F.A.Williams, “Combustion Theory,” Addison Wesley, 2nd Ed.

D.B.Spalding, “Combustion and Mass Transfer,” Pergamon

Press

I.Glassman, “Combustion,” Academic Press, 2nd Ed.

M.Kanury, “Introduction to Combustion Phenomena,” Gordon

and Breach Science Publishers

P.A.Libby and F.A.Williams (Editors), “Turbulent Reacting

Flows,” Springer Verlag

L.A.Kennedy (Editor), “Turbulent Combustion,” Progress in

Astronautics and Aeronautics, Vol.58

SYLLABUS (2/4)

K.K.Kuo, “Principles of Combustion,” Wiley

V.R.Kuznetsoz and V.A.Sabelnikov, “Turbulence and

Combustion,” Hemisphere Publishing Corporation

JOURNALS

Combustion and Flame

Combustion Science and Technology

Symposium (International) on Combustion

Combustion Theory and Modeling

AIAA Journal

Progress in Energy and Combustion Science

SYLLABUS (3/4)

Combustion, Explosion and Shock Waves

Progress in Astronautics and Aeronautics

Fire Safety Journal

International Journal of Heat and Mass Transfer

Journal of Heat Transfer

Journal of Thermophysics and Heat Transfer

Journal of Propulsion and Power

SYLLABUS (4/4)

Thermochemistry

Combustion- high temperature, moderate or high pressure,

perfect gas, real gas effects for high pressure environment

Thermodynamic properties of a single perfect gas

Equation of

state :

TRCTW

Rp

: Universal gas constant R

PROPULSION AND COMBUSTION LABORATORY

Kmole

energy

: Molecular weight W

mole

mass

: Concentration C

volumeunit

mole

Combustion Engineering

PROPULSION AND COMBUSTION LABORATORY Combustion Engineering

Internal Energy

u : per unit mass

dTTcuuT

TV

0

0

0u : Internal energy of formation

Vc : Specific heat

K mass

energy

Enthalpy

W

TRdTcu

W

TRu

puh

T

TV

0

0

or

W

TR

W

TRdT

W

Rc

W

TRuh

T

T P

00

00

= T

TP

dTTch0

0

0h : Enthalpy of formation



Only change in or is important (not the absolute level) h

0

u0

hNeed a convention for and

1) Prescribe a standard state, i.e., 0

T and 0p

2) The formation enthalpy of the chemical elements in their

natural phase at and will be zero. 0

T 0p

3) , atmp 10

KT 16.2980

0h for, gH

2: 0

0h gOH

2: 0

0h sC : 0

0h

gN2

: 00

h lH2

: 00

h

u


Entropy

T

T

P

p

p

W

RdT

T

css

00

0ln

Let = Entropy at and any temperature . 0s 0

p T

0

0

lnp

p

W

Rss

Gibbs Free Energy

Tshf per unit mass basis

0000TshTshf

0

0

0

0

ln)ln(p

p

W

TRf

p

p

W

RsThf

p

dp

W

R

T

dhds

d h v d pT d s d h v d p d s

T T


On a molar basis

0

0ln

p

pTRFFWf

F : Molar basis

Helmholtz Free Energy

Tsua

0

0

lnR T p

f fW p


TC : Total number of moles per unit volume

KC : Total number of moles of species K per unit volume

KX : Mole fraction of species K

K

KTCC

T

K

K

C

CX

K

KX 1

Mixture of perfect gases ;

222

cNbOaH


: Density of the mixture

K : Partial density of species K

KY : Mass fraction of species K

KW : Molecular weight of species K

K

KK

K

KCW

K

KY

, 1

K

KY

K

KK

K

KY

WWC


jK K

T K

K K jK K j

YYC C

W W W

K

/, Y

/

K K K K K K K K

K

T j j j j j j

j j j

C Y W W C W XX

C Y W W C W X

W : Mean molecular weight of the mixture

K

j

jj

j

jj

K K

K

K

KK

WYWY

W

YW

XWW/

1

/

K K K j j

K K j

W C W C K

KK

K

KY

WWC

K

KK

K

K

K

K

K

K

WXW

YW

W

Y

W

1

)(,1

EQUATION OF STATE

Partial pressure exerted by species K if it occupies

the whole volume at temperature T.

TRCpKK


Dalton’s Law

K K T T

K K

p p R T C C R T C W R T R T

but ,

K

T

K K

YC

W W

K K

KT

W

R

W

YTRp

Internal Energy

K

KKYuu


T

TVKK

dTTcuuK

00

0

0K

T

K K K K K VT

K K

u Y u Y u Y c T d T

T

TV

dTcuu0

0 where

K

KKuYu

00

T

TK

T

TVVK

T

TV

K

KdTcdTcYdTcY

KK0 00

K

VKVK

cYc


Enthalpy

K

KKhYh

T

TP

dTchh0

0 when is fixed KY

K

KKhYh

00

K

PKPK

cYc

Entropy

K

KKsYs


T

T

K

K

P

KK

p

p

W

RdT

T

css

K

00

0

ln

00

0

ln

KK P

TK K K

K K K KT

K K K K

Y cY p

s Y s Y s d T RT W p

K

K

K

KT

T

P

p

p

p

p

W

YRdT

T

cs

0

0lnln

0


T

T

P

p

p

W

RdT

T

css

00

0ln

K

K

K

KT

T

PX

W

YR

p

p

W

RdT

T

css lnln

0

00

0

0

0

1

ln ln

P

K

TP K

KT

K K

E n tr o p y in c r e a s e s d u e to m ix in gE n tr o p y th a t a p e r fe c t g a s o f W a n d c

X s o th a t p o s it iv e te r mw o u ld h a v e fo r p a n d T

c YR ps s d T R X

T W p W

K

KKfYf

0

0

lnp

p

W

TRff

K

K

KK

0

0ln

p

p

W

YTRff

K

K K

K


0

0

0

ln lnT

P K K

TK K

c Y p ps s d T R

T W p p

lnK K

K

RX X

W

KY

K K K K

j j

j

W X W X

W X W

K

K

K

K

XW

YTR

p

p

W

TRff lnln

0

0

p

K

P

T

hc

K

Caution ;

When there is reaction p

P

T

hc

K

KKhYh

p

K

K

K

p

K

K

K

pT

Yh

T

hY

T

h

p

K

K

K

p

P

T

Yh

T

hc


K

KKXX

W

TRln

0 0

0 0

ln ( ln ln )K K K K

K KK K

Y p Y ppf f R T f R T

W p W p p

KK

K

XY

W W

Problem for notes

Binary mixture of 422

HeH

,1

2

2

2

2

H

H

H

Y

YX

2

2

1

1

H

H

He

Y

YX

,12

HeHYY

HeH PHPHPcYcYc

222

1

Specification of Composition

,K K

p V N R T p V N R T For same

TV ,


j

j

j

K

K

K

W

Y

W

Y

X

/

/

K K K K

K

K

p N m W WY

p N m W W

,TW

RmpV

K

KK T

W

RmpV

For same P and T, partial volume of species K

K K K K K

K K

V m N W NW W

V m W N W W N

Here, is not so that V KV .

K

KY

m

m


Material Balance for Chemical Reactions

Ex) Combustion of Octane with Air

Air: 2222

176.379.021.0 Oof mole perNof molesNO

Molecular Weight: 298.282879.03221.0

For complete combustion (stoichiometric)

22222188

21

79

2

2598

21

79

2

25

2

25NOHCONOHC

Stoichiometric Coefficients: 1188

HC

,2/252

O21

79

2

25

2N


On a mass basis,

2821

79

2

25

2

189

2

448

2

)(1831

2821

79

2

25

2

322

25

2

114

188

21

79

2

2598

21

79

2

25

2

25

NOHCONOHC

gmsorlbs

or 15.1 kg of air/ 1 kg of octane

For reactants

0165.052.60

1

21

79

2

25

2

251

1

188

HC

X

,2065.052.60

2/25

2

O

X 7769.052.60

21/792/25

2

N

X



0623.01831

114

188

HC

Y

W

: MEAN MOLECULAR WEIGHT OF REACTANTS

3.3052.60

1831

MASS OF PRODUCTS = 1831

125.0

21

79

2

2598

8

2

CO

XRP

nn

2821

79

2

25

2

189

2

448

2

)(1831

2821

79

2

25

2

322

25

2

114

188

21

79

2

2598

21

79

2

25

2

25

NOHCONOHC

gmsorlbs


EQUIVALENCE RATIO :

tricstoichiomeoxidizerofmass

fuelofmass

oxidizerofmass

fuelofmass

FOR 1

22222476.32276.322 NOHCONOCH


1

1

1

: STOICHIOMETRIC

: FUEL LEAN

: FUEL RICH

FOR 9.0 224

76.3229.0 NOCH

FOR 1 differentCH 4

ENERGY Eq. FOR CHEMICAL REACTION

CONSTANT VOLUME SYSTEM – NO MOTION


1st LAW : WdEQ

Q

dE

W

: HEAT TRANSFER

(POSITIVE WHEN ADDED TO THE SYSTEM)

: INTERNAL ENERGY

: WORK DONE BY THE SYSTEM

1221EEQ

1: REACTANT STATE

2: PRODUCT STATE

ONLY IMPORTANCE IS , NOT THE ABSOLUTE VALUES.


E

BT

C25

: REFERENCE OR

BASIC TEMPERATURE

BE

: INTERNAL ENERGY OF REACTION,

DETERMINED IN A BOMB CALORIMETER


11122212EEEEEEEEQ

BBBB

ncompositiofixed

B

tabulated

B

ncompositiofixed

BEEEEE

11

22

FOR CONSTANT PRESSURE PROCESS;

VdpdHpdVdEWdEQ

1 2 2 1 2 2 2 1 1 1

B

B B B B

H

Q H H H H H H H H


BH

BE

: ENTHALPY OF REACTION

BBBBBBVpVpEH

1122

:INTERNAL ENERGY OF

REACTION AT B

T

FOR PERFECT GASES;

constpBconstVB

EE

2 1B B BH H H


BBBBBBBTRNTRNTRNVpVp

121122

12NNN BBB

TRNEH

2 2 1 1

2 1 2 2 2 1 1 1

B B B B B B

B B B B

H E p V p V

Q H H H H H H H H

ENTHALPY OF FORMATION AND ENTHALPY OF COMBUSTION

ENTHALPY OF FORMATION -THAT CHANGE OF ENTHALPY

WHICH OCCURS WHEN A COMPOUND IS FORMED FROM THE

ELEMENTS, WHICH ARE IN THEIR STABLE STATE, AT SAME

STANDARD TEMPERATURE AND PRESSURE.


gCOgOsC22

GIVES OFF 94052 cal :exothermic reaction

2

0

29 4 0 5 2 /

fC O

H ca l g m o le o f C O

HEAT OF FORMATION = 0

29 4 0 5 2 /

fH ca l g m o le o f C O

ALSO A COMBUSTION PROCESS

ENTHALPY OF COMBUSTION 0 0

29 4 0 5 2 /

c fH H ca l g m o le o f C O

2/94052 COofgmolecal

HEAT OF COMBUSTION OF

HEAT OF COMBUSTION

)(/12

94052)( sCof gcalsC


gNOgOgNEx222

2

1)

2

0/8091

2

NOofgmolecalHNOf

HEATING VALUES; FOR C+O2 REACTION,

BBEH , BECAUSE THERE IS NO WORKS. pdV

IN GENERAL,

HIGHER HEATING VALUES AND LOWER HEATING VALUES

DEPEND ON STATE OF PRODUCTS.

BBEH

ENDOTHERMIC REACTION

BBBTRNEH


IMPORTANT CASE IS vs. gOH2

lOH2

OHOH222

2

1

IF IS LIQUID,

LHV DIFFERS FROM HHV BY HEAT OF VAPORIZATION.

OH2

22

/32.34 HofgkcalOHHHV

2

2

2

2/9.28

9/602.0 Hofgkcal

Hofg

OHofgOHofgkcalHHVLHV


REFERENCES FOR THERMOCHEMICAL DATA

1. NBS, “Tables of Selected Values of Chemical Thermal

Properties”, Circular Letter 500

2. JANAF Thermo-Chemical Tables (1993)

3. Penner’s Book

4. Van Wylen & Sonntag (SI units)

5. CHEMKIN: Software package for the analysis of gas-

phase chemical and plasma kinetics (2000)

EXAMPLE

10g OF H2 (g) BURN IN AIR (=1) AT CONSTANT

PRESSURE. INITIAL TEMPERATURE IS 298K AND FINAL

TEMPERATURE IS 2000K SO THAT H2O IS GASEOUS.

CALCULATE THE HEAT LIBERATED ;


12HHQ

molesHofg 5102

)(4.9)(5)()76.3(2

5)(

2

5)(5

22222gNgOHgNgOgH

KgNKgOHHHH

2000),(2000),(222

4.95

KgNKgOKgHHHHH

298),(298),(298),(1222

4.92

55

molecal

HHHHKgOHfKKKgOH

7.40535577987.236719630

298),(,29820002000),(22

KgNfKgNHH

298),(,2000),(22

3.20728.15494


MINUS INDICATES THAT HEAT WAS

TRANSFERRED OUT OF THE SYSTEM. IN OTHER

WORDS, THE FLAME TEMPERATURE, IF ADIABATIC,

WOULD BE HIGHER THAN 2000 K.

IF THE PROBLEM WERE AT CONSTANT VOLUME,

0298),(298),(298),(

222

KgNKgOKgH

HHH

calQ 76512

12EEQ

TRNHpVHE

etc. ,20009807.15)7.40535(5

552000),(2000),( 22

calcal

TRNHEKgOHKgOH


CALCULATION OF ENTHALPY OF REACTION FROM

THE ENTHALPY OF FORMATION

REACTION ;

ReactantsProductsReaction

RfPfR

HHH

nNmMbBaA

Na

nM

a

mB

a

bA ro

AfBfNfMfAofmoleR

HHa

bH

a

nH

a

mH


EX) GASEOUS CH4 + O2 REACT TO YIELD H2O(l)+CO2(g).

CALCULATE PER MOLE OF CH4 R

H

kcal

HHHHHgOfgCHflOHfgCOfCHR

8.2129.1732.68205.94

22)()()()(

24224

)(2)()(2)(2224

lOHgCOgOgCH

EXOTHERMIC PER MOLE OF CH4


CONSIDER A CHEMICAL SYSTEM OF CONSTANT MASS

EITHER HOMOGENEOUS OR HETEROGENEOUS IN

MECHANICAL AND THERMAL EQUILIBRIUM BUT NOT IN

CHEMICAL EQUILIBRIUM. THE SYSTEM IS IN CONTACT

WITH A RESERVOIR AT TEMPERATURE T AND

UNDERGOES AN INFINITESIMAL IRREVERSIBLE

EXCHANGE OF HEAT, Q, TO THE RESERVOIR. PROCESS

MAY INVOLVE CHEMICAL REACTION AND TRANSPORT

BETWEEN PHASES.


FROM SYSTEM

dS: ENTROPY CHANGE OF THE SYSTEM

sQQ

0 dST

Qs

dSO: ENTROPY CHANGE OF THE RESERVOIR

dS+dSo: ENTROPY CHANGE OF THE UNIVERSE

0 dSdSO

T

QdS

O

0 dS

T

Q


FROM SYSTEM

1ST LAW sQ dE pdV

0 dST

Qs

0d E p d V T d S

VARIOUS CONSTRAINTS

CASE A ; HOLD E AND V CONSTANT

ISOLATED SYSTEM 0dS

CASE B ; HOLD p AND T CONSTANT

0d E p V T S d H T S d F

GIBBS FREE ENERGY DECREASES


WHEN ; HAVE CHEMICAL EQUILIBRIUM

AT EQUILIBRIUM ;

0,

TP

F

CASE C ; HOLD V AND T CONSTANT

0 dATSEd

0,

TV

A

-


EQUILBRIUM OF A MIXTURE OF PERFECT GASES

UNDERGOING CHEMICAL REACTION

CONSIDER THE REACTION,

dDcCbBaA

WE KNOW GIBBS FREE ENERGY FOR

AND ANY TEMPERATURE T PER MOLE.

AF atmP 1

0

AT ANY T AND P ;

0ln ppTRFF

AAA

0ln ppTRFF

BBB

, ETC

AF

0

0

0 0

0 0

ln

ln ln

K

K K

K

K K

K K K K K K

pR Tf f

W p

p pW f F W f R T F R T

p p


LET

BADCbFaFdFcFF

0 0

0 0

ln

c d

C D

a b

A B

p p p pF F RT

p p p p

01 P a tm

ln

c d

C D

a b

A B

p pF F RT

p p

BADCbFaFdFcFF

0 0 0 0

ln ln ln lnC D A B

C D A B

p p p pc F RT d F RT a F RT b F RT

p p p p

0

0

lnK

K K

pF F R T

p


NOTE THAT

AT EQUILIBRIUM

DEFINE e q u ilib r iu m c o n s ta n t b a s e d o n p re s s u re

c d

C D

P a b

A B

p pK

p p

0 F

PKTRF ln

F RT

PK e

)(TfF

)(TgKP

A

A

pX m o le fr a c t io n

p

B Bp p X

C Cp p X

D Dp p X


EFFECT OF T ON EQUILIBRIUM COMPOSITION IS GIVEN IN

Kp

EFFECTS OF p ON THE TERM.

FOR THE CASE OF , IE. C + D = A + B

NO PRESSURE EFFECT

EQUILIBRIUM CONSTANT BASED ON CONCENTRATION ;

WHERE

( )

c d c dc d a b nC D C D

P a b a b

A B A B

X X X XK p p

X X X X

)()( badcn

np

0 n

CK

volumeunit

moleionConcentratC


VALUES OF KP ARE TABULATED FOR SPECIFIC

CHEMICAL REACTION.

b

B

a

A

d

D

c

C

C

CC

CCK C C

p C RT , ETC

c d

n nC D

C pa b

A B

p pK RT K RT

p p

EX) DISSOCIATION OF CO2

22

2

1OCOCO 2

2

1 2

1

C O O

P

C O

p pK

p (1)


EX) 100% WATER VAPOR, INITIALLY AT 1 atm AND 2200

K DISSOCIATES INTO H2 (g) AND O2 (g). ASSUMING

PERFECT GASES THROUGHOUT, DETERMINE THE

EQUILIBRIUM COMPOSITION

EQUILIBRIUM COMPOSITION

(2) 22

2

1COOCO

2

2

1

2 11 / 2

C O

P P

C O O

pK K

p p

2222 COOCO (3)

2

12

2

3

2

2

P

OCO

CO

PK

pp

pK


CHEMICAL REACTION )(2

1)()(

222gOgHgOH

2 2 2 2

2 2

1 2 1 2

1 2H O H O

P

H O H O

p p X XK p

p X

2222cObHOaHOH EQUILIBRIUM COMPOSITION

caO

baH

21:

222:

2)1(

1

ac

ab

2222

2

)1(1 O

aHaOaHOH

2

3

2

)1()1(

aaaan

T


2

3

1

2 a

aX

H

2

3

2

1

2 a

a

XO

2

32 a

aX

OH

1 2

1 2

1

1 2

3 3

2 2,

3

2

P

a

a

a a

K pa

a

3 2 1 2

3

1 2

11 .1 4 5 1 0

3P

a PK

a a

2222

2

0137.00137.09863.0 OHOHOH

EQUILIBRIUM

COMPOSITION


EXAMINE LIMITING CONDITIONS

CASE I - LOW TEMPERATURES

; VERY LITTLE DISSOCIATION

LET 1a 1

21

2123

2

PK

P

32

31

2

PK

P

OR

A) HIGHER PRESSURE ; LOWER ; GREATER

LESS DISSOCIATION

B) HIGHER TEMPERATURE ; HIGHER KP GREATER ;

SMALLER

MORE DISSOCIATION

a

a

3 2 1 2

1 2

1

3P

a pK

a a

2222cObHOaHOH

2222

2

)1(1 O

aHaOaHOH


CASE II - HIGH TEMPERATURES ; HIGH DISSOCIATION

OR

A) HIGHER PRESSURE ; HIGHER ; HIGHER

LESS DISSOCIATION

B) HIGHER TEMPERATURE ; HIGHER KP ; LOWER =

MORE DISSOCIATION

a 1

21

21

3

PK

P

PK

P 1

3

21

a

a

3 2 1 2

1 2

1

3P

a pK

a a

2222

2

)1(1 O

aHaOaHOH


EQUILIBRIUM WHEN SIMULTANEOUS REACTIONS

OCCURRING

THE NUMBER OF INDEPENDENT REACTIONS, WHICH MUST

BE CONSIDERED IN EQUILIBRIUM CALCULATIONS, IS

EQUAL TO THE LEAST NUMBER OF EQUATIONS WHICH

INCLUDE ANY REACTANT AND PRODUCT WHICH ARE

PRESENT TO AN APPRECIABLE DEGREE IN THE

EQUILIBRIUM MIXTURE.

EX) CALCULATE THE COMPOSITION OF THE EQUILIBRIUM

MIXTURE OBTAINED WHEN 5 MOLES OF STEAM, H2O

(g) REACT WITH 1 MOLE OF CH4 AT ELEVATED

TEMPERATURE AND SOME ARBITRARY PRESSURE


MECHANISM FOR REACTION ;

2 ACTUAL REACTIONS ARE ;

C : 1 = a + c + e

H : 14 = 4a + 2b + 2d

O : 5 = b + c + 2e

2224245 eCOdHcCOObHaCHOHCH

2224

24

42723

5

CObaHbaCObaObHaCH

OHCH


03224

R

HHCOOHCH

0222

R

HHCOOHCO

(1)

(2)

2

4 2

3

1

C O H

P

C H H O

p pK

p p 2 2

2

2

C O H

P

C O H O

p pK

p p

aedcbanT

28

3 2

1 2

3 2 7 2

8 2P

a b a b pK

a b a

bba

babaK

P

23

274

2

2224

24

42723

5

CObaHbaCObaObHaCH

OHCH

3 2

8 2

.

C O C O

a bp X p p

a

e tc


(1)

(2)

eEcCaA

dDbBeE

dDcCbBaA ADD (3)

1

c e

C E

P a

A

p pK

p

2

d

D

P e b

E B

pK

p p

3 1 2

c d

C D

P P Pa b

A B

p pK K K

p p

PRODUCT RULE FOR KP’s


ADIABATIC FLAME TEMPERATURE 0Q

POINT (2) FINAL TEMPERATURE AND H AFTER

A NON-ADIABATIC REACTION

POINT (2i) ISOTHERMAL REACTION

POINT (c) ADIABATIC FLAME TEMPERATURE ; H2=H1


CONSTANT PRESSURE REACTION – GENERAL CASE

0Q

P

n

i

ii

R

m

i

iiBbAa

DETERMINE TC FROM H2=H1

H2 DEPENDS ON THE bi WHICH DEPENDS ON Tc WHICH

DEPENDS ON THE bi.

m

i

TATi

n

i

TBTiiiCiC

HaHb1

,,,,


FOR PERFECT GASES

WHERE

TO CALCULATE Tc

m

i

T

TPAfTi

n

i

T

TPBfTi

Bi

C

BiC

dTCHadTCHb1

1,,

r

m

iAfTi

n

iBfTi

HHaHbiiC

1,,

1. ASSUME TC FOR GIVEN PRESSURE

2. CALCULATE THE bi FROM THE KP’s

3. SUBSTITUTE INTO H2=H1

4. ITERATE UNTIL H2=H1


CALCULATE THE ADIABATIC FLAME TEMPERATURE

OF A = 0.8 METHANE – O2 MIXTURE AT p = 10 atm,

TAKING INTO ACCOUNT THE DISSOCIATION OF CO2

AND H2O

2 UNKNOWNS

OHCOOCH2224

220.1

22222428.08.0 eOdHcCOObHaCOOCH

2222

24

5.05.06.16.18.0

28.0

ObaHbCOaObHaCO

OCH

baedcbanT

5.05.04

T

CO

n

aX

2

T

O

n

eX

2

etc.

Dissociation Reactions

22

2

1OCOCO 2 2

2 2

1 12 2

12

1

C O O C O O

P

C O C O

p p X XK p

p X

222

2

1OHOH 2 2 2 2

2 2

1 12 2

12

2

H O H O

P

H O H O

p p X XK p

p X

12HH

1

21

42222

28.0TOTCHTOTHTCOTOHTCO

HHHeHdHcHbHaCCCCC

Combustion Engineering PROPULSION AND COMBUSTION LABORATORY

Procedure ; assume Tc; Calculate a,b,c,d,e

Substitute into H2=H1 (from Energy Equation)

If Tc=3000K


a[-94.05 kcal/mole + 38.94-2.24]+b[-57.8+32.16-2.37]

+c[-26.42+24.43-2.07]+d[0+23.19-2.02]

+e[0+25.52-2.07] = 0.8[-17.89]+2[0]

Hco2 HH20

Hco HH2

Ho2 HCH4 Ho2


Tables of Thermodynamic Properties














PROF SEUNG WOOK BAEK DEPARTMENT OF AEROSPACE …procom.kaist.ac.kr/Download/Combustion/Combustion 1.pdfK.K.Kuo, “Principles of Combustion,” Wiley V.R.Kuznetsoz and V.A.Sabelnikov,

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