Tutorials Manual

More documents

Recommendations

Info

Chemkin 4.1.1 Chapter 2: Combustion in Gas-phase Processes Setting up this problem first involves the C1 Equilibrium panel. The problem type (constant pressure and enthalpy), initial temperature (300 K) and pressure (1 atm) are entered on the Reactor Physical Properties tab. An estimated solution temperature of 2000 K is used to help ensure that the solution obtained is for an ignited gas rather than the unburned state. The presence of an estimated solution temperature is often unnecessary for equilibrium simulations but required when a trivial secondary solution may exist. The starting composition is entered on the Reactant sub-tab of the Species-specific Data tab. The reactant mixture defines the initial state, which provides the initial moles of chemical elements and the initial energy of the system. The Continuations panel is used to specify two additional simulations with increasing initial temperatures. 2.1.1.3 Project Results Figure 2-1 shows the equilibrium temperatures from these simulations, which represent the adiabatic flame temperatures for a hydrogen/air mixture with a H/O ratio of 2.0. The temperatures are on the order of ~2400 K, and thus clearly correspond to the combusted gas. As expected, these adiabatic flame temperatures increase with increasing initial gas temperature. Figure 2-1 Adiabatic Flame Temperatures—Hydrogen/Air Mixture 2.2 Using Equivalence Ratio Many properties of combustion processes strongly depend on the stoichiometry of the combustion mixture. The parameter used most frequently to describe the stoichiometry of the mixture is the equivalence ratio, φ . CHEMKIN gives the user an option of describing the initial mixture composition by either listing all of the reactant species and their respective mole or mass fractions, or identifying fuel, oxidizer and complete-combustion (stoichiometric) product species, the mole fraction of any © 2007 Reaction Design 18 RD0411-C20-000-001
Chapter 2: Combustion in Gas-phase Processes <strong>Tutorials</strong> <strong>Manual</strong> additional species (such as an inert like Ar or N 2 ) and the equivalence ratio. Examples of the use of the equivalence ratio can be found in Section 2.3.1, Steady-state Gasphase Combustion, and Section 2.3.6, Parameter Study: Varying Equivalence Ratio of Propane/Air Flame. 2.2.1 Example: Propane in Air Stoichiometric equation for propane in air combustion: C 3 H 8 +5(O 2 + 3.76N 2 ) → 3CO 2 +4H 2 O + 5 * 3.76N 2 Here, the equivalence ratio, φ , is defined as the ratio of the actual fuel/oxidizer ratio to the fuel/oxidizer ratio in the stoichiometric equation, as follows: X C3 H φ 8 ⁄ X O2 = ( ----------------------------------------- = X C3 H 8 ⁄ X O2 ) 5 ( X C3 H ⁄ X ) 8 O2 stoich CHEMKIN is able to interpret all of the input formats as illustrated in Tables 2-1 to 2-4: Table 2-1 Reactant Mole Fractions Sum to 1.0 Name Mole Fraction Reactant C 3 H 8 0.04 Reactant O 2 0.202 Reactant N 2 0.758 Table 2-2 Relative Moles Normalized So Mole Fractions Sum to 1.0 Name Mole Fraction Reactant C 3 H 8 0.2 Reactant O 2 1 Reactant N 2 3.76 RD0411-C20-000-001 19 © 2007 Reaction Design
Page 1 and 2: August 3, 2007 1:53 am Release 4.1.
Page 3 and 4: Chemkin 4.1.1 Contents Table of Con
Page 5 and 6: Chemkin 4.1.1 Tables List of Tables
Page 7 and 8: Tutorials Manual 4.1.1 Figures List
Page 9 and 10: List of Figures Tutorials Manual 2-
Page 11 and 12: List of Figures Tutorials Manual 4-
Page 13 and 14: Chemkin 4.1.1 1 1 Introduction The
Page 15 and 16: Chapter 1: Introduction Tutorials M
Page 17: Chemkin 4.1.1 2 2 Combustion in Gas
Page 21 and 22: Chapter 2: Combustion in Gas-phase
Page 69 and 70:
Chapter 2: Combustion in Gas-phase
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Chemkin 4.1.1 3 3 Catalytic Process
Page 93 and 94:
Chapter 3: Catalytic Processes Tuto
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Chemkin 4.1.1 4 4 Materials Problem
Page 117 and 118:
Chapter 4: Materials Problems Tutor
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Chemkin 4.1.1 5 5 Chemical Mechanis
Page 163 and 164:
Chapter 5: Chemical Mechanism Analy
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Tutorials Manual 4.1.1 Index Index
Page 179 and 180:
Index Tutorials Manual normalized s
show all

Tutorials Manual

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?