1.1 UQ and Optimization of kinetic mechanisms . . . . 5

Contents

Acknowledgements II

Summary IV

1 Introduction 1

1.1 UQ and Optimization of kinetic mechanisms . . . . 5

1.1.1 Literature review . . . . 7

1.2 Objectives of this work . . . . 10

2 Methodology 11 2.1 Selection of uncertain parameters . . . . 11

2.1.1 Local sensitivity analysis . . . . 11

2.1.2 Impact factor . . . . 13

2.1.3 Cumulative function . . . . 14

2.2 Uncertainty range of the kinetic parameters . . . . 14

2.2.1 Ensuring physically viable values . . . . 15

2.3 Objective function . . . . 17

2.4 Surrogate models . . . . 18

2.4.1 Kriging . . . . 19

2.5 Optimization algorithms . . . . 20

2.5.1 DIviding RECTangles (DIRECT) algorithm . . . . 20

2.5.2 Evolutionary Algorithm (EA) . . . . 21

3 Optimization of a chemical mechanism for MILD conditions 23 3.1 Experimental data . . . . 23

3.2 Choice of mechanism . . . . 24

3.2.1 Parameter selection . . . . 25

3.3 Optimization study . . . . 28

V

Contents

3.3.1 Validation against conventional conditions . . . . 32

3.4 Concluding remarks . . . . 33

4 OptiSMOKE++ 35 4.1 Workflow . . . . 35

4.1.1 OpenSMOKE++ . . . . 37

4.1.2 DAKOTA . . . . 37

4.2 Optimization targets . . . . 38

4.2.1 Ignition Delay Time (IDT) . . . . 38

4.2.2 Species profiles . . . . 39

4.2.3 Laminar Flame Speed (LFS) . . . . 39

4.3 Choice of objective function . . . . 39

4.4 Penalty function . . . . 40

4.5 Uncertain parameters . . . . 41

4.6 Test cases . . . . 42

4.6.1 Test case 1: Ignition Delay Time for MILD conditions in a Plug Flow Reactor . . . . 42

4.6.2 Test case 2: Ignition Delay Time at high pressures using data from a Shock-Tube . . . . 46

4.6.3 Test case 3: Methanol oxidation in a Jet Stirred Reactor . . . . 48

4.6.4 Test case 4: A combined optimization . . . . 51

4.6.5 Test case 5: Optimization of Laminar Flame Speed of methane diluted in CO

. . . . 54

4.6.6 Runtime and number of evaluations . . . . 55

4.7 Optimization of IDT for CH

and biomass pyrolysis products . . . . 56

4.8 Concluding remarks . . . . 59

5 Optimization of a kinetic mechanism for propane MILD combustion 61 5.1 Experimental database . . . . 61

5.2 Optimization strategy . . . . 62

5.3 Results . . . . 63

5.3.1 Validation against JSR data . . . . 68

5.4 Concluding remarks . . . . 71

6 Conclusions 73

Nomenclature 79

List of Figures 81

List of Tables 85

Appendices 87

Bibliography 101

VI