國立中央大學機械系
ME7076
燃
燒
學
（Combustion）
施聖洋 教授
(Prof. S. Shy)
Office: E2-413
Tel: (03)426-7327
Fax: (03)425-4501
E-mail: sshy@cc.ncu.edu.tw
Course Content
Chapter 1 Introduction to Combustion
Importance; Applications; Contribution
What is the Combustion Process?
Combustion Books & Journals & Proceedings
1.1 Preliminary remarks
1.2 Some Practical Problems in Combustion
1.3 Scientific Disciplines of Combustion
1.4 Classification of Fundamental Combustion Phenomena
1.5
What is the Combustion Process?
1.6 Books, Journals & Proceedings for Combustion
Chapter 2 Internal Combustion Engine and Its
Alternatives
Classification; Premixed Charge Engine;
Alternatives to IC Engines;
2.1
Internal Combustion Engine
2.2
Alternatives to IC Engines
Chapter 3 Chemical Thermodynamics
Equilibrium; Chemical Reaction;
Heat; Adiabatic Flame Temperature;
3.1 Equilibrium
3.2
Thermodynamics Laws
3.3
Chemical Thermodynamics and Flame Temperature
Chapter 4 Fuels and Stoichiometry
4.1 Fuels
4.2 Stoichiometry
4.3 Stoichiometry, Equivalence Ratio, and Adiabatic Flame
Temperature
Chapter 5 Thermodynamics Calculations of
Combustion Processes
5.1
Motivation
5.2 The energy equation
5.3 The second law as applied to a reacting system
5.4 Atom conservation
5.5
Application of energy, equilibrium, and atom conservation
5.6
Condensed phase
5.7
Reversible adiabatic compression / expansion
Chapter 6 Chemical Reactions and
Combustion
6.1 Types of flames
6.2 Chemical reactions
6.3 Application of chemical reaction to combustion processes
Chapter 1 Introduction to Combustion ME776
Section 1
Preliminary Remarks
1.1.1 Combustion
Interrelated processes of Fluid Mechanics, Heat & Mass Transfer, Chemical
Kinetics, Thermodynamics, and Turbulence.
Understanding of the fundamental concepts of these coupled processes will
provide engineers and scientists with the technical background and training
required to solve various combustion problems.
‧ "Everything that happens is due to the flow and transformation of energy......
Control fire and you control everything. The discovery of fire ...... lifted
man from the level of the beast and gave him dominion over the earth"
Morton Mott-Smith in his book of introduction to Heat and its Workings.
D. Appleton & Co.
(1933)
‧ Many burning issues in Combustion remain to be solved ; there has never
been a lack of demand for well-trained, dedicated combustion engineers and
scientists.
1.1.2 Some Comments about the Course
* This is a course in fundamental principles
* not in nuts-and-bolts design
* Throughout the course, emphasis will be on simple physical reasoning
backed by simple, approximate calculations (1-dimensional, ideal gas,
constant thermodynamic properties, etc.). Memorization of empirical results
(When A goes up, B decrease, etc.) won't work here. If the reasoning aren't
clear------ASK!
 In some sense, this course is really just a vehicle (Basic Concepts) to
study engineering systems in the future in which the trade off/judgments
are required, taking into account not just our back-of-the-envelope type
analyses But likely direction and magnitude of the errors which result.
Chapter 1 Introduction to Combustion ME776
Section 2
火
Some Practical Problems in
Combustion
文明
電、能源 etc. etc.
破壞
毀滅
生
5
1.2.1
污染
存
大
類
Devices
Fuels
Pollution and Health
Safety
Defense and Space
Energy and Combustion Devices

USA 發電方式
10% Nuclear, Solar, Wind, Hydro-electric, Geo. thermal, etc.
90 Chemical energy derived through combustion of fossil fuels
(Petroleum fuels).
This trend will continue in the foreseeable future.
(∵ convenience, high energy density, and the economics.)
1. Domestic Heating
Heat and Power
2. Firing of industrial furnaces
3.Operation of automotive engines and gas
turbines.
Design and operation of energy devices

Taiwan (民國 80 年)：see 所附之圖 (火力：58.1％； 水力：13.9％；
核能：28% )
民國 80 年：台灣發電方式
火力
水力
58.1％
合計
13.9％
18,383 MW
核能
28％

Auto Need more efficient and clean-burning internal
e.g.
combustion engines
Diesel Engine
 Cycle Efficiency <
Gasoline Engine
@ same compression ratio (C.R.).
 But operates at a higher C.R. (more efficiency overall).
 Not requires highly-refined fuels with narrow specifications.
 Can use nonconventional or low-grade fuels, e.g.
 Disadvantages:
e.g.
noisy & Heavy soot emitter.
New concept in engine development
alcohol.
ultralean
Stratified Charge Combustion
:
:
Rich
Overall fuel lean mixture easy to ignite.
Basic Idea
Lean Mixtures
Combustion efficiency
Pollutants formation
Hard to ignite
High pressure direct injection gasoline engine
simultaneously
1.2.2 Combustion needs fuel
e.g.
diesel oil
gasoline engine
Narrow compositional specifications of gases used in domestic
gas ranges.
Energy Crisis  Fuel Crisis
Shortage & reliability of petroleum supply.

Emphasis on Coal
Direct utilization
Fluid bed combustion
coal-derived fuels
· Higher boiling pt.
· Wider boiling pt. ranges
· Higher contents of aromatics and
nitrogen containing compounds
· more soot & NO2
Advantages:
· Direct contact w/ air
· max. burning rates
· SO2 ( limestones )
· NO2 (↓; fluidization rate )
Coal-water slurries
 Finely crushed coal particles
40 ~ 70 μm
 mixed in water
 Sprayed directly → combustion chamber of industrial furnaces
 Advantages:  less energy expansive than the chemical processes of
coal liquefaction.
 easy to transport in pipes
 min. hardware modification of oil-fired combustor
 70% coal content of slurries have been successfully burned.

Alternate & Hybrid Fuels
e.g.
methanol
&
Natural gas & coal
Ethanol
&
Ethanol
w/ oil
biomass (生質量 )
Ethanol: smaller heats of combustion
∵ extra oxygen atom in the mlc.
 Blends of 10% ethanol and 90% gasoline have been successfully.
1.2.3 Pollution and Health
Major Pollutants from Combustion
Soot
Coal-derived fuels
Diesel engine
Carcinogenic
SO x
Burning coal
Sulfuric acid
Water in atm
NO x
N 2 in atm
UHC
(unburned
CO
(carbon
N in fuel hydrocarbon) monoxide)
Thermal NO x
(organic liquid
Acid Rain
combustion products
---High T.
( dissociate inert N 2 in air)
condense on the
Fuel-bound NO x ---less T.
aquatic life
surface of the
soil erosion
soot particles)
致癌物質 ; 成癌質
sensitive major contributor
(burning coal or coal-derived oils)
NOx reacts w / UHC & ozone
by sunlight
smog (smoke + fog)
Detrimental to the respiratory sys.
Indoor Pollution (CO, NOx, UHC)
 Domestic heating devices
gas ranges
furnaces
Kerosene heaters
Incineration (chemical hazardous
wastes)
The uncertainty of the toxicity of the
combustion intermediates and products
e.g. Halogenated Compounds(鹵素)
（氟、氯、溴、碘）
incineration resistant
1.2.4 Safety
Fires
‧Structural & wild land
life & financial loss
‧Research improving
Explosions
Materials
‧Mine galleries
‧Inhalation of smoke &
‧Grain elevators
toxic products
‧Liquefied natural gases ‧Choice of structure &
fire detection tech.
‧Understanding the fire
spills
decoration
‧Nuclear reactor accidents
propagation in confined
spaces e.g. buildings &
a/c cabins
H2 gas
Containment
structure
Radioactive
gases
Fire control
1.2.5 Defense and Space

High-energy propellants.

The suppression of combustion instability within jets and rockets.

Signature and detection vulnerability from exhausts.

Measures at preventing explosion of fuel tank when being penetrated by
Projectiles.

The development of chemical lasers as an intense power source.
Chapter 1 Introduction to Combustion ME776
Section 3
Scientific Disciplines of Combustion
Combustion 
Chemically-reacting flows w/ rapid,
highly-exothermic reactions
Chemically Reacting Flows
Thermodynamics Fluid Mechanics
Heat and Mass Transfer
Chemical Kinetics
Material Structure and
Behaviour
Turbulence
1.3.1
Thermodynamics
Initial states
Reactants
Final states
Products
(Equilibrium)
Heat for utilization
Allows us to do the bookkeeping on how much chemical
energy can be converted to thermal energy in a combustion
process.
Determines the properties of the products ( T ; composition )
when equilibrium is reached.

Mature science & its laws have been firmly established.
1.3.2
Chemical Kinetics

What path and how long of such a process.

Conclusions based on equilibrium calculations could be quite
erroneous.
e.g.
a particular reaction needs 106 years for completion 當分析
cycle performance of an auto engine.
e.g. Calculation amount of NOx
Finite reaction rates  Thermodynamic equilibrium

All combustion processes have some finite, characteristic times
defining our interest in the phenomena.

Chemical Kinetics is needed to prescribe the paths and rates.

Thermodynamics can be considered to be a special area of
chemical kinetics in that with infinite time a reaction will
eventually achieve equilibrium.

A complex subject : a myriad of chemical species exist, each of
which has the potential of interacting w/ the
rest.

Some confidence on fuel oxidation system only for hydrogen, CO,
and the light alkanes.
1.3.3 Fluid Mechanics
Chemical reactions occurring in a flowing medium.
Combustion : Knowledge of F.M. is essential for a successful
understanding of many combustion phenomena.
Highly-localized and exothermic nature of chemical
reactions  significant temperature, and therefore
density variations in a flow, implying that fluid
incompressibility can be a rather poor assumption.
1.3.4 Transport Phenomena
SL ~ 40 cm/s ; D ~ 0.2 cm2/s
 ~ 0.2 / 40 = 510-3 cm = 0.05 mm
比一根頭髮還細
 Transfer of energy & mass from high to low; through the molecular
process of diffusion.
 For heat transfer, radiation is also important.
 Diffusive transport is crucial in the sustenance of many types of
flames in that it is only through these processes fresh reactants can
be continuously supplied to the flame while the heat generated there
is also being continuously used to heat up and thereby cause ignition
of these fresh mixture.
Chapter 1 Introduction to Combustion
Section 4
1.4.1
ME776
Classifications of Fundamental
Combustion Phenomena
Premixed and Nonpremixed Combustion
 Most important classification of combustion phenomena.
 Reactions generally involve two or more reactants.
Frequently
Essential
Elements
a fuel & an oxidizer
( molecular mixedness )
mixed at mlc level
Reaction
 Premixed system :
A+B
implies that at least one of the reactants
should be in either the gaseous or the
liquid phase so that its mlc. can spread
around those of the other reactant.
2B
( A : fuel + oxidizer ; B : heat and/or radicals )
 Nonpremixed system : Diffusional combustion reactants initially
separated, then being brought together, via molecular process of
diffusion and the bulk convective motion, to a common region where
mixing and subsequently reaction take place.
 Diffusion is still essential in transporting the premixture to, and the
thermal energy and combustion products away from, the flame region
where reactions occur.
 Bunsen Flames

As the fuel gas issues from the orifice, air is entrained through
the adjustable air-intake port and is then mixed with the fuel gas
as they travel along the burner tube.

The subsequent reactions between fuel and oxygen in this
premixture forms a premixed flame.

If this premixture is fuel rich ( has a high concentration of fuel
than can be consumed by all the oxygen in the entrained air ),
after passing through the premixed flame, the excess fuel ( or
rather the fuel-related intermediate species, can further react with
the oxygen in the ambient air.
Reactants initially separated
need to be transported to a
common region where mixing and reactions occur
Diffusion flame.
The outwardly-directed excess fuel reacts almost
completely w/ the inwardly-directed oxygen.
 It is obvious that one would not find many examples of premixtures in
nature, because they would have already reacted even if they are only
slightly reactive.
 Nonpremixed system abound.
Indeed w/ oxygen in the air as the oxidizer, then all the materials
which would burn in air are fuels.
e.g.
fossil deposits : petroleum & coal
cellulosic material : paper & cloth
metallic substances : aluminum & magnesium
1.4.2
Laminar and Turbulent Combustion
 Distinct streamlines exist for the bulk, convective motion ― Laminar
 Streamlines do not exist such that at any point in space the flow
quantities randomly fluctuate in time ― Turbulent
 Turbulent facilitates the coarse mixing process, and therefore has a
particularly strong influence on nonpremixed systems in which
reactant mixing is essential.

The final mixing before reactions can take place, however, must still
occur through the molecular diffusion process whether the flow is
laminar or turbulent.
1.4.3

Subsonic and Supersonic Combustion
The velocity of flow

Subsonic flow combustion : The molecular collision processes of
diffusion are predominant while
reactions also have more time to
complete.
Most frequently in our daily lives,
such as the candle flame and the pilot
flame.
瓦斯爐 標示燈等的火燄

Supersonic flow combustion: The high flow velocity usually
renders convective transport to
dominate over diffusive transport.
Reactions also have less time to
proceed.
Wave motions involving shocks and
rarefactions abound.
Explosions and supersonic flights.
1.4.4
Homogeneous and Heterogeneous Combustion
 Most confusing terminology in combustion literature
 Homogeneous :
If both reactants initially exist in the same fluid
phase, either gas or liquid. e.g. Bunsen flame.
Heterogeneous : If two reactants initially exist in different phases,
whether gas / liquid, liquid / solid, or solid / liquid,
then the combustion is heterogeneous. e.g. coal
particle burning in air.

Chemists define a heterogeneous reaction as one in which the
reactants actually exist in different phases at the location where
reaction takes place.

 Traditional combustion definition : Both modes of burning are called
heterogeneous combustion.
 To designate the uniformity of the mixture.
 Homogeneous  no temperature or concentration gradients in the
mixture.
 Heterogeneous  a gaseous mixture containing fuel vapor pockets
produced, say, through vaporization of fuel droplets.
Chapter 1 Introduction to Combustion ME776
Section 5
1.5.1
What is The Combustion Process?
Chemical Reaction
e.g. Methane burning in air
(1) The global reaction of methane and oxygen
CH4 + 2O2
CO2 + 2H2O
(2) The elementary reaction mechanism
( by T. P. Coffee,1984 )
Reaction
Ab
B
C
1.
OH + H2  H2O + H
1.17E9
1.3
1825
2.
H + O2  OH + O
1.42E14
0.0
8250
3.
O + H2  OH + H
1.80E10
1.0
4480
4.
H + O2 +M’  H2O +M’
1.03E18
- 0.72
5.
H + HO2  OH + OH
1.40E14
0.0
540
6.
H + HO2  O + H2O
1.00E13
0.0
540
7.
H + HO2  H2 + O2
1.25E13
0.0
0
8.
OH + HO2  H2O + O2
7.50E12
0.0
0
9.
O + HO2  OH + O2
1.40E13
0.0
540
10. O + HO2  OH + O2
1.25E12
0.0
0
11. H + H + H2  H2 + H2
9.20E16
- 0.6
0
12. H + H + N2  H2 + N2
1.00E18
- 1.0
0
13. H + H + O2  H2 + N2
1.00E18
- 1.0
0
14. H + H + HO2  H2 + O2
6.00E19
- 1.25
0
15. H + H + CO  H2 + CO
1.00E18
- 1.0
0
16. H + H + CO2  H2 + CO2
5.49E20
- 2.0
0
17. H + H + CH4  H2 + CH4
5.49E20
- 2.0
0
18. H + OH + M”  H2O +M”
1.60E22
- 2.0
0
19. H + O + M”  OH +M”
6.20E16
- 0.6
0
20. OH + OH  O + H2O
5.75E12
0.0
390
21. OH + CO  CO2 + H
1.50E7
1.3
-385
22. O + CO + M’  CO2 + M’
5.40E15
0.0
2300
23. H + CO + M’  CHO + M’
5.00E14
0.0
755
0
24. CH4 + O2  CH3 + OH
4.07E14
0.0
7040
25. CH4 + H  CH3 + H2
7.24E14
0.0
7590
26. CH4 + OH  CH3 + H2O
1.55E6
2.13
1230
27. CH4 + M  CH3 + H + M
4.68E17
0.0
46910
28. CH3 + O  CH2O + H
6.02E13
0.0
0
29. CH2O + O  CHO + OH
1.82E13
0.0
1550
30. CH2O + H  CHO + H2
3.31E14
0.0
5290
31. CH2O + OH  CHO + H2O
7.58E12E
0.0
72
32. CHO + O2  CO + H2O
3.00E12
0.0
0
33. CHO + H  CO + H2
4.00E13
0.0
0
34. CHO + OH  CO + H2O
5.00E12
0.0
0
35. CHO + O  CO + OH
1.00E13
0.0
0
36. CH2O + CH3  CHO + CH4
2.23E13
0.0
2590
37. CH3 + OH  CH2O + H2
3.98E12
0.0
0
38. CH3 + H2O  CH4 + O2
1.02E12
0.0
200
39. CO + H2O  CO2 + OH
1.50E14
0.0
11900
40. CH3 + CH3  C2 H6
4.56E37
- 7.65
4250
41. C2 H6 + O  C2 H5 + OH
2.51E13
0.0
3200
42. C2 H6 ++ H  C2 H5 + H2
5.00E2
3.5
2620
43. C2 H6 + OH  C2 H5 + H2O
6.63E13
0.0
675
44. C2 H5 + H  C2 H6
7.23E13
0.0
0
45. C2 H5 + H  CH3 + CH3
3.73E13
0.0
0
46. C2 H5  C2 H4 + H
2.29E11
0.0
19120
47. C2 H5 + O2  C2 H4 + H2O
1.53E12
0.0
2446
48. C2 H4 + O  CH2 + CH2O
2.53E13
0.0
2516
49. C2 H4 + OH  CH2O + CH3
5.00E13
0.0
3020
50. C2 H4 + O  C2 H3 + OH
2.53E13
0.0
2516
51. C2 H4 + O2  C2 H3 + HO2
1.33E15
0.0
27680
52. C2 H4 + H  C2 H3 + H2
2.00E15
0.0
10000
53. C2 H4 + OH  C2 H3 + H2O
4.40E14
0.0
3270
54. C2 H3 + M  C2 H2 + H + M
3.01E16
0.0
20380
55. C2 H3 + O2  C2 H2 + HO2
1.57E13
0.0
5030
56. C2 H3 + H  C2 H2 + H2
7.53E13
0.0
0
57. C2 H3 + OH  C2 H 2 + H2O
1.00E13
0.0
0
58. C2 H2 + OH  CH3 + CO
5.48E13
0.0
6890
59. CH3 + H  CH 2 + H2
2.00E11
0.7
-1500
60. CH3 + OH  CH 2 + H2O
6.00E10
0.7
1010
61. CH2 + O2  CHO + OH
1.00E14
0.0
1860
62. CH2 + O2  CH2O + O
1.00E14
0.0
1860
63. CH2 + O2  CO 2 + H2
a
b
c
1.00E14
0.0
1860
[M] = total concentration; [M’] = [H2] + 0.74[CO] + 1.47[CO2] + 0.35[O2] +
6.5[H2O] + 0.44[N2] ; [M”] = [H2] + [CO] + [CO2] + [O2] +5.0[H2O] + [N2]
A is in units of cm3/mole s or cm6/mole2 s, k = ATB exp(-C/T)
1.17E9 = 1.17  109
Westbrook and Dryer (1984)
150 forward reactions
Frenklach and Bornside (1984)
 Recently proposed chemical reaction mechanisms for soot formation
consist of as many as 2000 reactions.
Chapter 1 Introduction to Combustion
Section 6
ME776
Books, Journals & Proceedings for
Combustion
BOOKS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
S. S. Penner, “ Chemistry Problems in Jet Propulsion “ ,
Pergamon, 1957.
B. Lewis and G. von Elbe, “ Combustion, Flames and Explosions
of Gases “ , Qcademic, 1961.
C. P. Fenimore, “ Chemistry in Premixed Flames “ , Pergamon,
1964.
R. M. Fristrom and A. A. Westenberg, “ Flame Structure “ ,
McGraw-Hill, 1965.
A. G. Gaydon and H. G. Wolfhard, “ Flames “ , Chapman and Hall,
1970.
A. M. kanury, “ Introduction to Combustion phenomena “,
Gordon and Breach, 1975.
I. Glassman, “ Combustion “ , Qcademic, 1977.
D. B. Spalding, “ Combustion and Mass Transfer “ , Pergamon,
1979.
J. D. Buckmaster and G. S. S. Ludford, “ Theory of Laminar
Flame “ , Cambridge University Press, 1982.
T. Y. Toony, “ Combustion Dynamics “ , McGraw-Hill, 1983.
R. A. Strehlow, “ Combustion Fundamentals “ , McGraw-Hill,
1984.
F. A. Wiliams, “ Combustion Theory “ , 2nd Ed. Benjamin /
Cumring, 1985.
N. Chigier, “ Energy, Combustion and Environment “ ,
McGraw-Hill,1981.
A. W. Leferbore, “ Gas Turbine Combustion “ , McGraw-Hill,
1983.
Ya. B. Eeldovich, et. Al., “ The mathematical Theory of
Combustion and Explosion “ , translated by D. H. McNeil,
Consultants Bureau, 1985.
K. K. Kuo, “ Principles of Combustion “ , John Wiley and Sons,
1986.
D. E. Rosner, “ Transport processes in Chemically Reacting Flow
18.
19.
20.
21.
22.
systems “ , Butterworth, 1986.
E. S. Oran and J. P. Boris, “Numerical Simulation of Reactive
Flow “ , Elsevier, 1987.
D. Merrick, “ Coal Combustion and Conversion Technology “ ,
Elsevier, 1984.
K. Iinuma, T. Asanuma, T. Ohsawa and J. Doi, “ Laser Diagnostics
and Modeling of Combustion “ , Springer-Verlag, 1987.
A. C. Eckbreth, “ Laser Diagnostics for Combustion Temperature
and Species “ , Abacus, 1988.
C. K. Law 1996 ? Combustion ? ( Notes ; Draft )
1989
JOURNALS and PROCEEDINGS
(for COMBUSTION)
1.
2.
3.
Acta Astronautica
AIAA Journal
ASME Transaction : Journal of Heat Transfer and
Journal of Engineering for Power
4.
5.
6.
7.
8.
9.
10.
11.
12.
Combustion and Flame
Combustion, Explosion, and Shock Waves
Combustion Science and Technology
International Journal of Heat and Mass Transfer
Journal of Chemical Physics
Journal of Fluid Mechanics
Physics of Fluid
Progress in Energy and Combustion Science
Proceedings of the International Symposia on
Combustion