1. Introduction to turbulent combustion modeling

Luc Vervisch and Pascale Domingo - CORIA - CNRS, INSA Rouen, Normandy University, France

1.1 Background and challenges

1.2 Major length and time scales

1.3 Generic scalar balance equation

1.3.1 Eddy viscosity - RANS & LES

1.4 Modeling review
1.4.1 Fixed flame structure
1.4.2 Micro-mixing modeling
1.4.3 LES-specialized turbulent combustion modeling

1.5 Conclusion

2. Combustion Chemistry

Ulrich Maas - Karlsruhe Institute of Technology, Germany

2.1 Introduction
2.2 Chemical Source Terms
2.2.1 Need for source terms
2.2.2 Rate laws
2.2.3 Rate laws for elementary reactions

2.3 Combustion Kinetics
2.3.1 Formation of Radicals
2.3.2 Fuel oxidation

2.4 Time Scales of Chemical Kinetics

2.5 Detailed Reaction Mechanisms
2.5.1 State of the art
2.5.2 Different strategies for the mechanism development
2.5.3 Different strategies for optimization
2.5.4 Available Detailed Mechanisms
2.5.5 Implementation
2.5.6 General remarks

2.6 Skeleton Mechanisms
2.6.1 Construction of skeleton mechanisms based on intuition
2.6.2 Mathematical analysis
2.6.3 General remarks
2.6.4 Adaptive Chemistry

2.7 Principles of Reduced Kinetic Models

2.8 Knowledge Based Model Reduction

2.8.1 Methods for Analysis
2.8.2 Implementation of steady state and partial equilibrium assumptions

2.9 Manifold Methods
2.9.1 Principles of Manifold Methods
2.9.2 Identification of Low-Dimensional Manifolds

2.10 Global Mechanisms

2.11 Tabulation Strategies

2.12 Implementation of reduced schemes

2.13 Conclusions

3. Thermal Radiation

Pedro J. Coelho - Universidade de Lisboa, Lisboa, Portugal
Marco Mancini - Technische Universität Clausthal, Germany
Dirk J.E.M. Roekaerts - Delft University of Technology, The Netherlands

3.1 Radiative Heat Transfer in Combustion Systems
3.1.1 Radiative transfer equation
3.1.2 Absorptivity, emissivity, transmissivity
3.1.3 Radiative heat flux and radiative source term

3.2 Solution Methods for Thermal Radiation
3.2.1 Optically thin approximation
3.2.2 Optically thick approximation
3.2.3 Spherical harmonics method
3.2.4 Discrete transfer method (DTM)
3.2.5 Discrete ordinates method (DOM)
3.2.6 Finite volume method (FVM)
3.2.7 Monte Carlo method
3.2.8 Other solution methods

3.3 Radiative Properties of Gases
3.3.1 Line-by-line model
3.3.2 Narrow band models
3.3.3 Wide band models
3.3.4 Correlated k-distribution method
3.3.5 Global models
3.3.6 Total gas radiative properties
3.3.7 Other gas property models

3.4 Radiative Properties of Particles
3.4.1 Radiative properties of soot particles
3.4.2 Radiative properties of coal particles
3.4.3 Radiative properties of biomass particles
3.4.4 Radiative properties of droplets
3.4.5 Radiative properties of porous media

3.5 Turbulence-Radiation Interaction

3.6 Computational Implementation of Radiation Models

3.7 Summary of Guidelines
3.7.1 Selection of the radiation model and RTE solution method
3.7.2 Selection of the radiative properties model
3.7.3 Computational implementation

3.8 Examples of Validation Studies and Applications
3.8.1 Example 1: Comparison of radiative transfer models
3.8.2 Example 2: Comparison of spectral models
3.8.3 Example 3: Application to a laboratory combustor (BERL furnace)
3.8.4 Example 4: Application to MILD combustion

4. RANS and LES validation

Friedrich Dinkelacker - Leibniz Universität Hannover, Germany Andreas Kempf - Universität Duisburg-Essen,Germany
Guido Kuenne - Technische Universität Darmstadt, Germany
Michael Pfitzner - Universität der Bundeswehr München, Germany

4.1 Reacting versus non-reacting CFD validation
4.1.1 Why validate a CFD code?
4.1.2 Validation of Combustion CFD codes
4.1.3 Steps in a CCFD validation process
4.1.4 Analysis of CCFD validation simulations
4.1.5 Differences in CCFD validation for RANS and LES codes

4.2 Non premixed validation flames
4.2.1 Combustion physics
4.2.2 Overview of some available validation flames
4.2.3 Piloted Jet Flames
4.2.4 Bluff-Body Flame
4.2.5 Conclusions and best practice guidelines non premixed flames

4.3 Fully premixed validation flames
4.3.1 Combustion Physics and Remarks for Usability as Validation Flames
4.3.2 Premixed Turbulent Validation Flames
4.3.3 Atmospheric 48 mm Bunsen Flames from Erlangen
4.3.4 High Pressure Bunsen Flames from Orléans
4.3.5 Large Sudden Expansion Combustor from PSI
4.3.6 Conclusions and best practice guidelines for premixed turbulent flames

4.4 Partially premixed / stratified validation flames
4.4.1 Combustion physics
4.4.2 Overview over validation flames
4.4.3 Swirl burner (TECFLAM)
4.4.4 Stratified burner
4.4.5 Conclusions and best practice guidelines for partially premixed flames

4.5 General conclusions

5. Sooting flames

Stelios Rigopoulos - Imperial College London, UK

5.1 Introduction
5.1.1 Fundamental processes in soot formation

5.2 Soot models
5.2.1 Taxonomy and historical overview of soot models
5.2.2 Semi-empirical non-precursor models
5.2.3 PAH formation
5.2.4 Nucleation
5.2.5 Surface growth and oxidation

5.3 Soot aerosol dynamics
5.3.1 The particle size distribution
5.3.2 The Population Balance Equation (PBE)

5.4 Solution of the PBE
5.4.1 Method of moments and variants
5.4.2 Discretisation methods

5.5 Coupling of soot models with flow

5.6 Turbulent combustion and soot
5.6.1 Closure problem for soot in turbulent flow
5.6.2 Fundamentals of turbulence-soot interaction
5.6.3 Modelling of turbulence-soot interaction - monodisperse and moment-based models
5.6.4 Modelling of turbulence-soot interaction - discretised PBE

5.7 Choice of models
5.7.1 Choice of combustion mechanism for soot modelling
5.7.2 Suggested configurations

6. Internal Combustion Engine

Amsini Sadiki, Francesca di Mare and Kaushal Nishad - Darmstadt University of Technology, Germany

Peter Keller, Stefan Buhl, Frank Hartmannand and Christian Hasse - TU Bergakademie Freiberg, Germany

6.1 Introduction
6.1.1 Generalities
6.1.2 Engine Typologies and Technology Trends
6.1.3 Structure of this Chapter

6.2 On Turbulent Flow Modelling in IC Engines
6.2.1 Large Eddy Simulation for ICE
6.2.2 Hybrid URANS/LES and their Applications in IC Engines
6.2.3 Numerical Methods, Quality Assessment and Postprocessing
6.2.4 Best Practice Guidelines

6.3 Spray Description, Atomization and Modelling
6.3.1 Generalities
6.3.2 Spray Description
6.3.3 Spray Atomization Models
6.3.4 Single Component Spray Modeling
6.3.5 Best Practice Guidelines

6.4 Multicomponent Droplet Evaporation
6.4.1 Introduction and Outline
6.4.2 Review of Modeling Approaches
6.4.3 Model Formulation
6.4.4 Application Examples
6.4.5 Best Practice Guidelines

6.5 Ignition Process and Combustion Models
6.5.1 Ignition Process
6.5.2 Combustion Models
6.5.3 Best Practice Guidelines

6.6 Best Practice for Combustion LES and HLR
6.6.1 Choice of Models
6.6.2 Choice of Mesh
6.6.3 Choice of Discretisation Scheme
6.6.4 Choice of Time Step
6.6.5 Statistics and Required Number of Engine Cycles

6.7 Validation and Concluding Remarks

7. Gas - Turbines

Laurent Y.M. Gicquel, O. Vermorel, Florent Duchaine, Eleonore Riber, Antoine Dauptain, G. Staffelbach, Benedicte Cuenot and Thierry Poinsot - CFD Combustion Team, CERFACS Toulouse, France

7.1 Introduction
7.2 Modeling and computational issues
7.2.1 Combustor components
7.2.2 Turbulent combustion modeling
7.2.3 Modeling versus computing power

7.3 Pre-requisites for e_cient CFD case studies
7.3.1 Setup phase
7.3.2 Run monitoring
7.3.3 Validation and exploitation
7.3.4 Recommendations to new CFD users

7.4 Conclusions and perspectives

8. Emerging Methods

Bénédicte Cuenot - CERFACS, Toulouse, France, cuenot@cerfacs.fr

Dominique Thévenin, Univ. of Magdeburg ‘Otto von Guericke’, Magdeburg, Germany, thevenin@ovgu.de

8.1 Introduction: why should you read this chapter?

8.2 Present problems and (future) solutions

8.3 The no-model approach: Direct Numerical Simulation

8.4 Developing, testing, and calibrating models

8.5 Solving computational limitations

8.6 Advanced and alternative numerical techniques

8.7 Uncertainty Quantification

8.8 Conclusions