Modelling Diesel Combustion

1. Auflage 2010
ISBN: 978-90-481-3885-2
Verlag: Springer-Verlag
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 305 Seiten

Phenomenology of Diesel Combustion and Modeling Diesel is the most efficient combustion engine today and it plays an important role in transport of goods and passengers on land and on high seas. The emissions must be controlled as stipulated by the society without sacrificing the legendary fuel economy of the diesel engines. These important drivers caused innovations in diesel engineering like re-entrant combustion chambers in the piston, lower swirl support and high pressure injection, in turn reducing the ignition delay and hence the nitric oxides. The limits on emissions are being continually reduced. The- fore, the required accuracy of the models to predict the emissions and efficiency of the engines is high. The phenomenological combustion models based on physical and chemical description of the processes in the engine are practical to describe diesel engine combustion and to carry out parametric studies. This is because the injection process, which can be relatively well predicted, has the dominant effect on mixture formation and subsequent course of combustion. The need for improving these models by incorporating new developments in engine designs is explained in Chapter 2. With “model based control programs” used in the Electronic Control Units of the engines, phenomenological models are assuming more importance now because the detailed CFD based models are too slow to be handled by the Electronic Control Units. Experimental work is necessary to develop the basic understanding of the pr- esses.

Autoren/Hrsg.

Inhaltsverzeichnis

1;Acknowledgments;8
2;Preface;9
3;Contents;11
4;1 Introduction;14
4.1;Role of Internal Combustion Engines;14
4.2;Developments in DI Diesel Engines;15
4.3;Modelling of Combustion in DI Diesel Engines;19
4.4;References;20
5;2 Phenomenology of Diesel Combustion and Modelling;21
5.1;Combustion Model;22
5.1.1;Ignition delay;22
5.1.2;Heat release;23
5.1.3;Models based on fluid dynamics;23
5.1.4;Phenomenological models;23
5.1.5;Zero-dimensional models;24
5.2;Emission Models;26
5.3;Theme of the Book;29
6;3 Experiments;34
6.1;Studies in a Bomb;34
6.1.1;Engine – bomb similarity;36
6.1.2;Vaporisation studies;37
6.1.3;Combustion studies;38
6.2;Real Engine Studies;40
7;4 Turbulent Structure of the Diesel Spray;49
7.1;Vaporising Spray;49
7.1.1;Free jet region;49
7.1.2;Jet penetration and entrainment of air;56
7.2;Combusting Sprays;59
7.3;Summary of the Model for Vapourising and Combusting Sprays;63
7.4;Modern View of the Vaporising and Burning Spray;65
8;5 Ignition Delay in a Diesel Engine;69
8.1;Definition and Measurement of Ignition Delay;70
8.2;Classical Model for Ignition Delay and Its Extension to Other Fuels;71
8.2.1;Validation of classical model;72
8.3;Phenomenological Model of Ignition Delay;73
8.3.1;Mechanism of ignition delay;73
8.3.2;Spray formation;74
8.3.3;Mass transfer;77
8.3.4;Reactions;78
8.3.5;Ignition delay;80
8.3.6;Extent of reaction within the spray;80
8.3.7;Turbulence;82
8.3.8;Computations;82
8.3.9;Validation of the model;82
8.3.10;Effect of orifice size;83
8.3.11;Effect of injection quantity;83
8.3.12;Effect of Cetane number;84
8.3.13;Effect of volatility;84
8.3.14;Summary;85
8.3.15;References;87
9;6 Heat Transfer;89
9.1;Heat Transfer Across the Walls;89
9.2;Heat Transfer Coefficient at the Wall Where the Spray Impinges;90
9.3;Heat Transfer from Spray to the Wall;91
9.4;References;92
10;7 Heat Release in Indirect Injection Engines;93
10.1;Description of the Phenomenological Model;94
10.1.1;Combustion model;94
10.1.2;Heat transfer;100
10.1.3;Gas exchange model;100
10.1.4;Friction power;100
10.1.5;Calculation procedure;100
10.2;Experimental Technique;100
10.3;Results and Discussions;101
10.4;Conclusions;104
10.5;References;107
11;8 Mixing Correlations for Smoke and Fuel Consumption of Direct Injection Engines;108
11.1;Characteristic Parameter for Air Fuel Mixing in a Cross Flow;109
11.1.1;The concept of useful air;110
11.1.2;Calculation of momentum of injected fuel;112
11.1.3;Calculation of momentum of useful air;115
11.1.4;Characteristic mixing parameter of an engine;115
11.2;Validation of the Mixing Parameter;116
11.2.1;Input data for the validation of the correlation;116
11.2.2;Results;117
11.3;Conclusion;120
11.4;References;120
12;9 Heat Release in Direct Injection Engines;122
12.1;Heat Release Rate in Diesel Engines;123
12.1.1;Single dimensional models;123
12.1.2;Multidimensional models;123
12.1.3;Mixing controlled combustion;124
12.2;Model for Mixing Controlled Combustion;126
12.2.1;Regimes of combustion in a modern DI diesel engine;126
12.2.2;Two factors affecting heat release rate;127
12.2.3;k-e theory;128
12.2.4;Modified k-e model;128
12.2.5;Input rate and dissipation rate of turbulent kinetic energy of fuel spray;129
12.2.6;Energy input;129
12.2.7;Calculation of fuel injection rate;130
12.2.8;Energy dissipation;131
12.2.9;Density of turbulent energy;131
12.3;Modelling three regimes of heat release rate;132
12.4;Steps to calculate heat release rate using the new model;133
12.4.1;Step 1: Prediction of impingement and loss in kinetic energy;133
12.4.2;Step 2: Computation of factors of rate of heat release;134
12.4.3;Step 3: Resultant rate of heat release;134
12.5;Experimental Validation;134
12.6;Heat release rate from the experiments;134
12.6.1;Engines A9, B9 and C9;134
12.6.2;Engine D9;135
12.7;Estimation of heat transfer across the walls;135
12.8;Results;135
12.8.1;Parametric studies of Engine A9;135
12.8.2;Base data at rated 100% load and 2,700 rpm;137
12.8.3;Other loads and speeds;137
12.8.4;Study of Engine-B9;138
12.8.5;Engine-C9 and Engine-D9;138
12.8.6;Engine-E9;138
12.9;Discussions;139
12.10;Summary;144
12.11;References;145
13;10 Hydrocarbons from DI Diesel Engines;146
13.1;Injection characteristics and the indicated diagrams;147
13.2;HC Model;148
13.2.1;Spray structure;148
13.2.2;Ignition delay;148
13.2.3;Fuel injected during delay;149
13.2.4;Over-leaned fuel air mixture;149
13.2.5;Fuel effusing the injector sac;150
13.2.6;Other sources of hydrocarbons;150
13.2.7;Formation of unburned hydrocarbons;150
13.3;Predicting HC in the Exhaust;152
13.3.1;HC and fuel injected during delay;152
13.3.2;Specific HC in the exhaust;153
13.3.3;Phenomenological model;153
13.4;Discussions;154
13.5;Summary;155
13.6;References;155
14;11 Hydrocarbon Emissions from Spark Ignition Engines;156
14.1;Description of the Engine Model;158
14.1.1;Breathing;158
14.1.2;Combustion;159
14.1.3;HC emissions;161
14.1.4;The contribution of ring crevice to HC emission;164
14.1.5;Oxidation of HC during exhaust;164
14.1.6;Solution procedure;164
14.2;Comparison of the Model Prediction with Engine Experiments;165
14.3;Conclusions;173
14.4;References;174
15;12 Smoke from DI Diesel Engines;176
15.1;Phenomenon of Soot Formation;177
15.2;Application to Engine Conditions;180
15.2.1;Correlating smoke: phenomenon with spray characteristics;182
15.2.2;Benchmarking with well known smoke model;194
15.2.3;Transient conditions;195
15.3;References;196
16;13 Oxides of Nitrogen from Direct Injection Diesel Engines;198
16.1;Exhaust Gas Recirculation (EGR);203
16.2;Phenomenology of Oxides of Nitrogen;204
16.2.1;Effect of EGR;206
16.2.2;Effect of oxygen in the fuel;208
16.3;References;210
16.4;Before detachment;201
16.5;After detachment;202
16.6;Phenomenon of Heat Transfer;203
17;14 Particulate Matter from Direct Injection Diesel Engines;211
17.1;Phenomenology of Particulate Matter (PM);211
17.2;Validation of Correlation;213
17.3;ReferencesCartillieri W,;214
18;15 Multi-dimensional Modelling of DieselCombustion: Review;215
18.1;Basic Approach;216
18.2;Turbulence Modelling;218
18.2.1;RANS models;218
18.2.2;Large Eddy simulation (LES);219
18.3;Spray and Evaporation Modelling;220
18.3.1;Spray models;221
18.3.2;Evaporation models;224
18.4;Combustion Modelling;226
18.4.1;Shell/CTC model;226
18.4.2;Direct integration of chemical kinetics;228
18.5;Pollutant Emissions Modelling;231
18.5.1;NOx modelling;231
18.5.2;Soot modelling;233
18.5.3;CO and UHC modelling;234
18.6;Heat Transfer Modelling;235
18.7;Efficient Multi-dimensional Simulation of Diesel Engine Combustion with Detailed Chemistry;237
18.7.1;Adaptive multi-grid chemistry (AMC) model;237
18.7.2;Mesh-independent spray models;241
18.7.3;Code parallelization;244
18.8;CFD Codes for Engine Simulation;246
18.8.1;Open source codes;247
18.8.2;Commercial software;249
18.9;Future and Challenge;249
18.10;References;250
19;16 Multi-dimensional Modelling of DieselCombustion: Applications;255
19.1;Case Studies;256
19.1.1;Study of UHC/CO emissions trends;256
19.1.2;Study of engine size-scaling relationships for a light-duty and a heavy-duty diesel engine;269
19.1.3;Results and discussion;276
19.1.4;Optimisation of a heavy-duty engine at low- and high-loads;280
19.1.5;Results and discussion;284
19.1.6;References;289
20;Appendices;291
20.1;Appendix I: Estimation of Products of Combustion from the Interferogram;291
20.2;Appendix II: Estimation of Concentration of Fuel Vapour in the Vapourising and Combusting Spray from the Interferogram;292
20.3;Appendix III: Estimation of Mass and Heat Transfer Functions;293
20.4;Appendix IV: Vapour Pressure of Diesel and Fuels A & B and B*;293
20.5;Appendix V: Calculation of Tangential Velocity of Air in the Piston Cavity from the Inlet Swirl Number;294
20.6;Appendix VI: Momentum of Useful Air of the Three Different Combustion Cavities Described in Kuo et al. (1988);294
20.7;Appendix VII: Momentum of Useful Air for Engines A8, B8, C8 and D8;295
20.8;Appendix VIII: Estimation of Spray Properties andImpingement Parameters;296
20.9;Appendix IX: Calculation of Fuel Injection Rate;298
20.10;Appendix X: Influence of Nozzle Features;299
20.11;Appendix XI: Henry’s Constant Hc for Fuel (n-Octane) in Oil;300
20.12;Appendix XII: Evaluation of gF* and gG*;301
20.13;Appendix XIII: In-Cylinder Oxidation of HC;302
20.14;Appendix XIV: Estimation of Wall Surface Temperature;305
20.15;Appendix XV: Experimental Data on HC Emissions from DI Diesel Engines;306
20.16;References;307
21;Index;309