Engineering webinar material dealing with power cycles (Carnot, Brayton, Otto and Diesel) and combustion when air, argon, helium and nitrogen are considered as the working fluid.

1. Engineering Software
P.O. Box 2134
Kensington, MD 20891
Phone (301) 919-9670
E-Mail: info@engineering-4e.com
http://www.engineering-4e.com
Copyright © 1996

2. Power Cycles and Combustion Analysis
Webinar Objectives
In this webinar, the engineering students and professionals get familiar with
the ideal simple and basic power cycles and combustion and their T - s, p - V
and h - T diagrams, operation and major performance trends when air, argon,
helium and nitrogen are considered as the working fluid.
Performance Objectives:
Introduce basic energy conversion engineering assumptions and equations
Know basic elements of Carnot Cycle, Brayton Cycle, Otto Cycle, Diesel
Cycle and combustion and their T - s, p - V and h - T diagrams
Be familiar with Carnot Cycle, Brayton Cycle, Otto Cycle, Diesel Cycle and
combustion operation
Understand general Carnot Cycle, Brayton Cycle, Otto Cycle, Diesel Cycle
and combustion performance trends

3. This webinar consists of the following two major sections:
• Power Cycles (Carnot, Brayton, Otto and Diesel)
• Combustion
In this webinar, first overall engineering assumptions and basic engineering
equations are provided. Furthermore, for each major section, basic
engineering equations, section material and conclusions are provided.
Power Cycles and Combustion Analysis
Webinar

4. The energy conversion analysis presented in this webinar considers ideal (isentropic) operation and air, argon,
helium and nitrogen are considered as the working fluid. Furthermore, the following assumptions are valid:
Power Cycles
Single species consideration -- fuel mass flow rate is ignored and its impact on the properties of the working
fluid
Basic equations hold (continuity, momentum and energy equations)
Specific heat is constant
Power Cycle Components/Processes
Single species consideration
Basic equations hold (continuity, momentum and energy equations)
Specific heat is constant
Thermodynamic and Transport Properties
Single species consideration
Ideal gas approach is used (pv=RT)
Specific heat is not constant
Coefficients describing thermodynamic and transport properties were obtained from the NASA Glenn Research
Center at Lewis Field in Cleveland, OH -- such coefficients conform with the standard reference temperature of
298.15 K (77 F) and the JANAF Tables
Engineering Assumptions

5. Basic Conservation Equations
Continuity Equation
m = ρvA [kg/s]
Momentum Equation
F = (vm + pA)out - in [N]
Energy Equation
Q - W = ((h + v2/2 + gh)m)out - in [kW]
Basic Engineering Equations

6. Ideal Gas State Equation
pv = RT [kJ/kg]
Perfect Gas
cp = constant [kJ/kg*K]
Kappa
χ = cp/cv [/]
Basic Engineering Equations

7. Basic Engineering Equations
Physical Properties
Gas Constant
[kJ/kg*K]
0.2867
0.2801
2.0785
0.2969
Specific Heat
[kJ/kg*K]
1.004
0.519
5.200
1.038
χ
[/]
1.4
1.67
1.66
1.4
Working Fluid
Air
Argon
Helium
Nitrogen

8. Power Cycles Engineering Equations
Carnot Cycle Efficiency
 = 1 - TR/TA
Otto Cycle Efficiency
 = 1 - 1/ε(χ-1)
Brayton Cycle Efficiency
 = 1 - 1/rp
(χ-1)/χ
Diesel Cycle Efficiency
 = 1 - (φχ-1)/ (χε(χ-1)(φ-1))
Cycle Efficiency
 = Wnet/Q [/]
Heat Rate
HR = (1/)3,412 [Btu/kWh]
rp = p2/p1 [/]; ε = V1/V2 [/]; φ = V3/V2 [/]

9. Power Cycles Engineering Equations
Otto Cycle
wnet = qh - ql = cv(T3 - T2) - cv(T4 - T1) [kJ/kg]
Wnet = wnetm [kW]
Brayton Cycle
wnet = qh - ql = cp(T3 - T2) - cp(T4 - T1) [kJ/kg]
Wnet = wnetm [kW]
Diesel Cycle
wnet = qh - ql = cp(T3 - T2) - cv(T4 - T1) [kJ/kg]
Wnet = wnetm [kW]

10. Power Cycles Engineering Equations
Isentropic Compression
T2/T1 = (p2/p1)(χ-1)/χ [/]
T2/T1 = (V1/V2)(χ-1) [/]
p2/p1 = (V1/V2)χ [/]
wc = cp(T2 - T1) [kJ/kg]
Wc = cp(T2 - T1)m [kW]

11. Power Cycles Engineering Equations
Isentropic Expansion
T1/T2 = (p1/p2)(χ-1)/χ [/]
T1/T2 = (V2/V1)(χ-1) [/]
p1/p2 = (V2/V1)χ [/]
we = cp(T1 - T2) [kJ/kg]
We = cp(T1 - T2)m [kW]

12. Carnot Cycle Schematic Layout
Compressor
Heat Exchanger
Gas Turbine
1
3
2
4
Heat Addition
Heat Exchanger
Heat Rejection
Carnot Cycle

13. Carnot Cycle T - s Diagram
1
3
2
4
Temperature
--
T
[K]
Entropy -- s [kJ/kg*K]
Carnot Cycle

14. Carnot Cycle Efficiency
0
20
40
60
80
500 600 700 800 900 1,000
Carnot
Cycle
Efficiency
[%]
Heat Addition Temperature [K]
Compressor Inlet Temperature: 298 [K]
Carnot Cycle

15. Carnot Cycle Efficiency
0
20
40
60
80
278 288 298 308 318 328
Carnot
Cycle
Efficiency
[%]
Heat Rejection Temperature [K]
Turbine Inlet Temperature: 800 [K]
Carnot Cycle

16. Brayton Cycle (Gas Turbine) Schematic Layout -- Open Cycle
Compressor
Combustor
Gas Turbine
1
3
2
4
Fuel
Brayton Cycle (Gas Turbine)
Heat Addition
Working Fluid In Working Fluid Out

17. Brayton Cycle Schematic Layout -- Closed Cycle
Compressor
Heat Exchanger
Gas Turbine
1
3
2
4
Heat Addition
Heat Exchanger
Heat Rejection
Brayton Cycle (Gas Turbine)

18. Brayton Cycle (Gas Turbine) T - s Diagram
1
3
2
4
Temperature
--
T
[K]
Entropy -- s [kJ/kg*K]
Brayton Cycle (Gas Turbine)

19. Brayton Cycle (Gas Turbine) Efficiency
0
20
40
60
80
5 10 15 20 25
Compression Ratio (P2/P1) [/]
Brayton
Cycle
(Gas
Turbine)
Efficiency
[%]
Air Argon Helium Nitrogen
Brayton Cycle (Gas Turbine)

20. Brayton Cycle (Gas Turbine) Specific Power
Output
0
500
1,000
1,500
2,000
2,500
900 1,200 1,500
Gas Turbine Inlet Temperature [K]
Brayton
Cycle
(Gas
Turbine)
Specific
Power
Output
[kJ/kg]
Air Argon Helium Nitrogen
Compression Ratio (P2/P1) = 15 [/]
Brayton Cycle (Gas Turbine)
Compressor Inlet Temperature: 298 [K]

21. Brayton Cycle (Gas Turbine) Power Output
0
100
200
300
400
50 100 150
Working Fluid Mass Flow Rate [kg/s]
Brayton
Cycle
(Gas
Turbine)
Power
Output
[MW]
Air Argon Helium Nitrogen
Compression Ratio (P2/P1) = 15 [/]
Compressor Inlet Temperature: 298 [K] -- Gas Turbine Inlet Temperature: 1,500 [K]
Brayton Cycle (Gas Turbine)

22. Brayton Cycle (Gas Turbine)
Oxidant Composition
Fuel Composition
C
[kg/kg]
0.000
H
[kg/kg]
0.000
S
[kg/kg]
0.000
N
[kg/kg]
0.000
O
[kg/kg]
0.000
H2O
[kg/kg]
0.000
CH4
[kg/kg]
1.000
Fuel
Gas
N
[kmol/kmol]
0.790
O
[kmol/kmol]
0.210
N
[kg/kg]
0.767
O
[kg/kg]
0.233
Oxidant
Air

23. Brayton Cycle (Gas Turbine)
Combustion Products Composition on Weight and Mole Basis
CO2
[kg/kg]
0.016
0.036
0.059
H2O
[kg/kg]
0.013
0.030
0.048
N2
[kg/kg]
0.763
0.757
0.751
O2
[kg/kg]
0.209
0.177
0.143
CO2
[kmol/kmol]
0.010
0.024
0.038
Stoichiometry
[/]
10.05
4.35
2.68
N2
[kmol/kmol]
0.782
0.771
0.760
Combustion Products Flame Temperature and Oxidant to Fuel Ratio
Flame Temperature
[K]
900
1,200
1,500
Oxidant to Fuel Ratio
[/]
172.525
74.675
46.007
H2O
[kmol/kmol]
0.021
0.047
0.075
O2
[kmol/kmol]
0.187
0.158
0.127
Stoichiometry
[/]
10.05
4.35
2.68

24. 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kg/kg] Combustion Products -- Weight Basis
900 1,200 1,500
Brayton Cycle (Gas Turbine)
Fuel Temperature: 298 [K] -- Oxidant Temperature: 646 [K]
Gas Turbine Inlet Temperature [K]

25. 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kmol/kmol] Combustion Products -- Mole Basis
900 1,200 1,500
Brayton Cycle (Gas Turbine)
Fuel Temperature: 298 [K] -- Oxidant Temperature: 646 [K]
Gas Turbine Inlet Temperature [K]

26. Brayton Cycle (Gas Turbine) Specific Fuel
Consumption
0.00
0.01
0.02
0.03
900 1,200 1,500
Gas Turbine Inlet Temperature [K]
Brayton
Cycle
(Gas
Turbine)
Specific
Fuel
Consumption
[kg/kg]
HHV Combustion
Compression Ratio (P2/P1) = 15 [/]
Brayton Cycle (Gas Turbine)
Compressor Inlet Temperature: 298 [K]

27. Brayton Cycle (Gas Turbine) Stoichiometry
0
4
8
12
900 1,200 1,500
Gas Turbine Inlet Temperature [K]
Stoichoimetry [/]
Compression Ratio (P2/P1) = 15 [/]
Brayton Cycle (Gas Turbine)
Compressor Inlet Temperature: 298 [K]
Brayton
Cycle
(Gas
Turbine)
Stoichiometry
[/]

28. Otto Cycle p - V Diagram
1
3
2
4
Pressure
--
p
[atm]
Volume -- V [m^3]
Otto Cycle

29. Otto Cycle T - s Diagram
1
3
2
4
Temperature
--
T
[K]
Entropy -- s [kJ/kg*K]
Otto Cycle

30. Otto Cycle Efficiency
0
20
40
60
80
2.5 5 7.5 10 12.5
Compression Ratio (V1/V2) [/]
V1/V2 [/]
Working Fluid: Air
Otto Cycle
Otto
Cycle
Efficiency
[%]

31. Otto Cycle Power Output
100
200
300
400
1,200 1,500 1,800
Combustion Temperature [K]
Otto
Cycle
Power
Output
[kW]
5 10
Compression Ratio (V1/V2) [/]
Working Fluid: Air
Ambient Temperature: 298 [K] -- Number of Revolutions: 60 [1/s]
For Given Geometry of the Four Cylinder and Four Stroke Otto Engine
Otto Cycle

32. Otto Cycle
Oxidant Composition
Fuel Composition
C
[kg/kg]
0.860
H
[kg/kg]
0.140
S
[kg/kg]
0.000
N
[kg/kg]
0.000
O
[kg/kg]
0.000
H2O
[kg/kg]
0.000
CH4
[kg/kg]
0.000
Fuel
Gasoline
N
[kmol/kmol]
0.790
O
[kmol/kmol]
0.210
N
[kg/kg]
0.767
O
[kg/kg]
0.233
Oxidant
Air

33. Otto Cycle
Combustion Products Composition on Weight and Mole Basis
CO2
[kg/kg]
0.028
0.049
0.072
H2O
[kg/kg]
0.011
0.020
0.029
N2
[kg/kg]
0.760
0.755
0.750
O2
[kg/kg]
0.200
0.176
0.150
CO2
[kmol/kmol]
0.019
0.032
0.047
Stoichiometry
[/]
7.53
4.30
2.93
N2
[kmol/kmol]
0.783
0.778
0.762
Combustion Products Flame Temperature and Oxidant to Fuel Ratio
H2O
[kmol/kmol]
0.018
0.032
0.046
O2
[kmol/kmol]
0.180
0.159
0.135
Flame Temperature
[K]
1,200
1,500
1,800
Oxidant to Fuel Ratio
[/]
110.306
62.990
42.921
Stoichiometry
[/]
7.53
4.30
2.93

34. 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kg/kg]
Combustion Products -- Weight Basis
1,200 1,500 1,800
Otto Cycle
Fuel Temperature: 298 [K] -- Oxidant Temperature: 748.5 [K]
Combustion Temperature [K]

35. 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kmol/kmol]
Combustion Products -- Mole Basis
1,200 1,500 1,800
Otto Cycle
Fuel Temperature: 298 [K] -- Oxidant Temperature: 748.5 [K]
Combustion Temperature [K]

36. 0.00
0.01
0.02
0.03
1,200 1,500 1,800
Otto
Cycle
Specific
Fuel
Consumption
[kg/kg]
Combustion Temperature [K]
Otto Cycle Specific Fuel Consumption
HHV Combustion
Compression Ratio (V1/V2) = 10 [/]
Otto Cycle
Ambient Temperature: 298 [K]

37. 0
2
4
6
8
1,200 1,500 1,800
Combustion Temperature [K]
Otto Cycle Stoichiometry
Stoichoimetry [/]
Compression Ratio (V1/V2) = 10 [/]
Otto Cycle
Ambient Temperature: 298 [K]
Otto
Cycle
Stoichiometry
[/]

38. Diesel Cycle p - V Diagram
1
3
2
4
Pressure
--
p
[atm]
Volume -- V [m^3]
Diesel Cycle

39. Diesel Cycle T - s Diagram
1
3
2
4
Temperature
--
T
[K]
Entropy -- s [kJ/kg*K]
Diesel Cycle

40. Diesel Cycle Efficiency
0
20
40
60
80
7.5 10 12.5 15 17.5
Compression Ratio (V1/V2) [/]
Diesel
Cycle
Efficiency
[%]
3 4
Working Fluid: Air
Cut Off Ratio V3/V2 [/]
Diesel Cycle

41. Diesel Cycle Efficiency
20
40
60
80
1,500 1,800 2,100
Combustion Temperature [K]
Diesel
Cycle
Efficiency
[%]
10 15
Compression Ratio (V1/V2) [/]
Diesel Cycle
Ambient Temperature: 298 [K]

42. Diesel Cycle Cut Off Ratio
0
1
2
3
4
1,500 1,800 2,100
Combustion Temperature [K]
Diesel
Cycle
Cut
Off
Ratio
[/]
10 15
Compression Ratio (V1/V2) [/]
Diesel Cycle
Ambient Temperature: 298 [K]

43. Diesel Cycle Power Output
200
300
400
500
600
1,500 1,800 2,100
Combustion Temperature [K]
Diesel
Cycle
Power
Output
[kW]
10 15
Working Fluid: Air
Diesel Cycle
Ambient Temperature: 298 [K] -- Number of Revolutions: 60 [1/s]
For Given Geometry of the Four Cylinder and Four Stroke Diesel Engine
Compression Ratio (V1/V2) [/]

44. Diesel Cycle
Oxidant Composition
Fuel Composition
C
[kg/kg]
0.860
H
[kg/kg]
0.140
S
[kg/kg]
0.000
N
[kg/kg]
0.000
O
[kg/kg]
0.000
H2O
[kg/kg]
0.000
CH4
[kg/kg]
0.000
Fuel
Diesel
N
[kmol/kmol]
0.790
O
[kmol/kmol]
0.210
N
[kg/kg]
0.767
O
[kg/kg]
0.233
Oxidant
Air

45. Diesel Cycle
Combustion Products Composition on Weight and Mole Basis
CO2
[kg/kg]
0.054
0.084
0.115
H2O
[kg/kg]
0.022
0.033
0.046
N2
[kg/kg]
0.754
0.747
0.739
O2
[kg/kg]
0.170
0.136
0.100
CO2
[kmol/kmol]
0.036
0.055
0.075
Stoichiometry
[/]
3.90
2.50
1.81
N2
[kmol/kmol]
0.776
0.769
0.761
Combustion Products Flame Temperature and Oxidant to Fuel Ratio
H2O
[kmol/kmol]
0.035
0.054
0.073
O2
[kmol/kmol]
0.153
0.123
0.091
Flame Temperature
[K]
1,500
1,800
2,100
Oxidant to Fuel Ratio
[/]
57.131
36.622
26.514
Stoichiometry
[/]
3.90
2.50
1.81

46. 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kg/kg] Combustion Products -- Weight Basis
1,500 1,800 2,100
Diesel Cycle
Fuel Temperature: 298 [K] -- Oxidant Temperature: 880.3 [K]
Combustion Temperature [K]

47. 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kmol/kmol] Combustion Products -- Mole Basis
1,500 1,800 2,100
Diesel Cycle
Fuel Temperature: 298 [K] -- Oxidant Temperature: 880.3 [K]
Combustion Temperature [K]

48. Diesel Cycle Specific Fuel Consumption
0.00
0.01
0.02
0.03
0.04
1,500 1,800 2,100
Combustion Temperature [K]
Diesel
Cycle
Specific
Fuel
Consumption
[kg/kg]
HHV Combustion
Compression Ratio (V1/V2) = 15 [/]
Diesel Cycle
Ambient Temperature: 298 [K]

49. Diesel Cycle Stoichiometry
0
2
4
6
1,500 1,800 2,100
Combustion Temperature [K]
Stoichoimetry [/]
Compression Ratio (V1/V2) = 15 [/]
Diesel Cycle
Ambient Temperature: 298 [K]
Cut Off Ratio (V3/V2) = 1.70, 2.05 and 2.39 [/]
Diesel
Cycle
Stoichiometry
[/]

50. Power Cycles Conclusions
The Carnot Cycle efficiency increases with an increase in the heat addition temperature when the heat rejection
temperature does not change at all. Furthermore, the Carnot Cycle efficiency decreases with an increase in the
heat rejection temperature when the heat addition temperature does not change at all. The Carnot Cycle efficiency
is not dependent on the working fluid properties.
The Brayton Cycle efficiency depends on the compression ratio working fluid properties. The efficiency increases
with an increase in the compression ratio values. Also, the efficiency increases with the higher value for ϰ, which is
a ratio of gas specific heat values (cp/cv).
The Brayton Cycle specific power output increases with an increase in the gas turbine inlet temperature for a fixed
compression ratio. Also, the Brayton Cycle specific power output and power output increase for the working fluid
having higher specific heat values. The Brayton Cycle power output increases with an increase in the working fluid
mass flow rate for the fixed gas turbine inlet temperature and compression ratio values.
The Otto Cycle efficiency increases with an increase in the compression ratio values. Also, the Otto Cycle power
output increases with an increase in the combustion temperature. The Otto Cycle power output is greater for the
higher compression ratio values for the given combustion temperature values and geometry of the four cylinder and
four stroke Otto engine.
The Diesel Cycle efficiency increases with an increase in the compression ratio and with a decrease in the cut off
ratio values. Also, the Diesel Cycle power output increases with an increase in the compression ratio values for the
given combustion temperature values and geometry of the four cylinder and four stroke Diesel engine.
For Brayton Cycle, Otto Cycle and Diesel Cycle, specific fuel consumption is greater for the ideal and complete
combustion calculations than for the calculations based upon fuel higher heating value.

51. Combustion Engineering Equations
Combustion is ideal, complete with no heat loss and
fuel reacts with air at different stoichiometry values
(stoichiometry => 1) and air (oxidant) inlet temperature
values.
Also,
Flame Temperature [K]
hreactants = hproducts [kJ/kg]

52. Combustion Schematic Layout
Fuel
Oxidant
Combustion Products
Combustion

53. Specific Enthalpy vs Temperature
-20,000
-10,000
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
500 800 1,100 1,400 1,700 2,000 2,300 2,600 2,900 3,200 3,500 3,800 4,100 4,400 4,700 5,000
C(S) H2 S(S) N2 O2 H2O(L) CH4 CO2 H2O SO2
Combustion
Specific
Enthalpy
[kJ/kg]
Temperature [K]

54. Combustion h - T Diagram
Specific
Enthalpy
--
h
[kJ/kg]
Temperature -- T [K]
Reactants
Products
Tflame
Treference
Combustion

55. Combustion
Oxidant Composition
Fuel Composition
C
[kg/kg]
1.000
0.000
0.000
0.780
0.860
-
H
[kg/kg]
0.000
1.000
0.000
0.050
0.140
-
S
[kg/kg]
0.000
0.000
1.000
0.030
0.000
-
N
[kg/kg]
0.000
0.000
0.000
0.040
0.000
-
O
[kg/kg]
0.000
0.000
0.000
0.080
0.000
-
H2O
[kg/kg]
0.000
0.000
0.000
0.020
0.000
-
CH4
[kg/kg]
-
-
-
-
-
1.000
Fuel
Carbon
Hydrogen
Sulfur
Coal
Oil
Gas
N
[kmol/kmol]
0.790
O
[kmol/kmol]
0.210
N
[kg/kg]
0.767
O
[kg/kg]
0.233
Oxidant
Air

56. Combustion
CO2
[kg/kg]
0.295
0.000
0.000
0.249
0.202
0.151
H2O
[kg/kg]
0.000
0.255
0.000
0.041
0.080
0.124
SO2
[kg/kg]
0.000
0.000
0.378
0.005
0.000
0.000
N2
[kg/kg]
0.705
0.745
0.622
0.705
0.718
0.725
O2
[kg/kg]
0.000
0.000
0.000
0.000
0.000
0.000
CO2
[kmol/kmol]
0.210
0.000
0.000
0.170
0.132
0.095
Fuel
Carbon
Hydrogen
Sulfur
Coal
Oil
Gas
SO2
[kmol/kmol]
0.000
0.000
0.210
0.002
0.000
0.000
N2
[kmol/kmol]
0.790
0.653
0.790
0.759
0.739
0.715
Combustion Products Flame Temperature, Stoichiometric Oxidant to Fuel Ratio and HHV
Flame Temperature
[K]
2,460
2,525
1,972
2,484
2,484
2,327
Stoichiometric
Oxidant to Fuel Ratio
[/]
11.444
34.333
4.292
10.487
14.694
17.167
HHV
[Btu/lbm]
14,094
60,997
3,982
14,162
20,660
21,563
Fuel
Carbon
Hydrogen
Sulfur
Coal
Oil
Gas
H2O
[kmol/kmol]
0.000
0.347
0.000
0.068
0.129
0.190
O2
[kmol/kmol]
0.000
0.000
0.000
0.000
0.000
0.000
Stoichiometric Combustion
Combustion Products Composition on Weight and Mole Basis

57. Combustion Products -- Weight Basis
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O SO2 N2 O2
Combustion
Products
[kg/kg]
Carbon Hydrogen Sulfur Coal Oil Gas
Combustion
Fuel and Oxidant Inlet Temperature: 298 [K]

58. Combustion Products -- Mole Basis
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O SO2 N2 O2
Combustion
Products
[kmol/kmol]
Carbon Hydrogen Sulfur Coal Oil Gas
Combustion
Fuel and Oxidant Inlet Temperature: 298 [K]

59. Combustion Products Flame Temperature
1,900
2,000
2,100
2,200
2,300
2,400
2,500
2,600
Carbon Hydrogen Sulfur Coal Oil Gas
Flame Temperature [K]
Combustion
Fuel and Oxidant Inlet Temperature: 298 [K]
Flame
Temperature
[K]

60. Combustion Stoichiometric Oxidant to Fuel Ratio
0
5
10
15
20
25
30
35
40
Carbon Hydrogen Sulfur Coal Oil Gas
Stoichiometric Oxidant to Fuel Ratio [/]
Combustion
Fuel and Oxidant Inlet Temperature: 298 [K]
Stoichiometric
Oxidant
to
Fuel
Ratio
[/]

61. Higher Heating Value (HHV)
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Carbon Hydrogen Sulfur Coal Oil Gas
HHV [Btu/lbm]
Combustion
Fuel and Oxidant Inlet Temperature: 298 [K]
HHV
[Btu/lbm]

62. Combustion
Oxidant Composition
Fuel Composition
C
[kg/kg]
1.000
0.000
0.000
0.780
0.860
-
H
[kg/kg]
0.000
1.000
0.000
0.050
0.140
-
S
[kg/kg]
0.000
0.000
1.000
0.030
0.000
-
N
[kg/kg]
0.000
0.000
0.000
0.040
0.000
-
O
[kg/kg]
0.000
0.000
0.000
0.080
0.000
-
H2O
[kg/kg]
0.000
0.000
0.000
0.020
0.000
-
CH4
[kg/kg]
-
-
-
-
-
1.000
Fuel
Carbon
Hydrogen
Sulfur
Coal
Oil
Gas
N
[kmol/kmol]
0.790
O
[kmol/kmol]
0.210
N
[kg/kg]
0.767
O
[kg/kg]
0.233
Oxidant
Air

63. Combustion
Stoichiometric Combustion
Flame Temperature
Hydrogen
[K]
2,525
2,583
2,640
2,689
2,757
2,818
2,879
2,942
Sulfur
[K]
1,972
2,045
2,118
2,191
2,267
2,343
2,421
2,501
Coal
[K]
2,484
2,551
2,618
2,686
2,756
2,827
2,899
2,972
Oil
[K]
2,484
2,551
2,616
2,683
2,751
2,820
2,891
2,963
Preheat Temperature
[K]
298
400
500
600
700
800
900
1,000
Combustion Products Stoichiometric Oxidant to Fuel Ratio and HHV
Stoichiometric
Oxidant to Fuel Ratio
[/]
11.444
34.333
4.292
10.487
14.649
17.167
HHV
[Btu/lbm]
14,094
60,997
3,982
14,162
20,660
21,563
Fuel
Carbon
Hydrogen
Sulfur
Coal
Oil
Gas
Gas
[K]
2,327
2,391
2,455
2,520
2,586
2,653
2,721
2,791
Carbon
[K]
2,460
2,531
2,602
2,674
2,747
2,822
2,898
2,976

64. Combustion Products Flame Temperature
0
1,000
2,000
3,000
298 400 500 600 700 800 900 1,000
Flame
Temperature
[K]
Carbon Hydrogen Sulfur Coal Oil Gas
Combustion
Fuel Inlet Temperature: 298 [K]
Oxidant Preheat Temperature for Stoichiometric Combustion Conditions

65. Combustion
Oxidant Composition
Fuel Composition
C
[kg/kg]
0.000
H
[kg/kg]
0.000
S
[kg/kg]
0.000
N
[kg/kg]
0.000
O
[kg/kg]
0.000
H2O
[kg/kg]
0.000
CH4
[kg/kg]
1.000
Fuel
Gas
N
[kmol/kmol]
0.790
O
[kmol/kmol]
0.210
N
[kg/kg]
0.767
O
[kg/kg]
0.233
Oxidant
Air

66. Combustion
Combustion Products Composition on Weight and Mole Basis
CO2
[kg/kg]
0.151
0.078
0.052
0.040
0.032
0.026
H2O
[kg/kg]
0.124
0.064
0.043
0.032
0.026
0.022
N2
[kg/kg]
0.725
0.745
0.753
0.756
0.758
0.760
O2
[kg/kg]
0.000
0.113
0.152
0.172
0.184
0.192
CO2
[kmol/kmol]
0.095
0.050
0.034
0.026
0.020
0.018
Stoichiometry
[/]
1
2
3
4
5
6
N2
[kmol/kmol]
0.715
0.750
0.763
0.770
0.774
0.776
Combustion Products Flame Temperature and Oxidant to Fuel Ratio
Flame Temperature
[K]
2,327
1,480
1,137
951
832
750
Oxidant to Fuel Ratio
[/]
17.167
34.333
51.500
68.667
85.833
103.000
H2O
[kmol/kmol]
0.190
0.100
0.068
0.051
0.041
0.034
O2
[kmol/kmol]
0.000
0.100
0.135
0.153
0.165
0.172
Stoichiometry
[/]
1
2
3
4
5
6

67. Combustion Products -- Weight Basis
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kg/kg]
1 2 3 4 5 6
Fuel and Oxidant Inlet Temperature: 298 [K]
Combustion
Stoichiometry [/]

68. Combustion Products -- Mole Basis
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
CO2 H2O N2 O2
Combustion
Products
[kmol/kmol]
1 2 3 4 5 6
Fuel and Oxidant Inlet Temperature: 298 [K]
Combustion
Stoichiometry [/]

69. Combustion Products Flame Temperature
600
900
1,200
1,500
1,800
2,100
2,400
1 2 3 4 5 6
Flame Temperature [K]
Combustion
Stoichiometry [/]
Fuel and Oxidant Inlet Temperature: 298 [K]
Flame
Temperature
[K]

70. Combustion Oxidant to Fuel Ratio
0
30
60
90
120
1 2 3 4 5 6
Oxidant to Fuel Ratio [/]
Combustion
Stoichiometry [/]
Fuel and Oxidant Inlet Temperature: 298 [K]
Oxidant
to
Fuel
Ratio
[/]

71. Combustion Conclusions
Hydrogen as the fuel has the highest flame temperature, requires the most mass
amount of oxidant in order to have complete combustion per unit mass amount of fuel
and has the largest fuel higher heating value.
When hydrogen reacts with oxidant, there is no CO2 present in the combustion
products.
The flame temperature increases as the oxidant, air, preheat temperature increases
for a fixed stoichiometry value.
The flame temperature decreases as the stoichiometry values increase.