Stabilization and Dynamic of Premixed Swirling Flames

Stabilization and Dynamic of Premixed Swirling Flames: Prevaporized, Stratified, Partially, and Fully Premixed Regimes focuses on swirling flames in various premixed modes (stratified, partially, fully, prevaporized) for the combustor, and development and design of current and future swirl-stabilized combustion systems. This includes predicting capabilities, modeling of turbulent combustion, liquid fuel modeling, and a complete overview of stabilization of these flames in aeroengines. The book also discusses the effects of the operating envelope on upstream fresh gases and the subsequent impact of flame speed, combustion, and mixing, the theoretical framework for flame stabilization, and fully lean premixed injector design.

Specific attention is paid to ground gas turbine applications, and a comprehensive review of stabilization mechanisms for premixed, partially-premixed, and stratified premixed flames. The last chapter covers the design of a fully premixed injector for future jet engine applications.

• Features a complete view of the challenges at the intersection of swirling flame combustors, their requirements, and the physics of fluids at work
• Addresses the challenges of turbulent combustion modeling with numerical simulations
• Includes the presentation of the very latest numerical results and analyses of flashback, lean blowout, and combustion instabilities
• Covers the design of a fully premixed injector for future jet engine applications

Aerospace and mechanical engineers, researchers, masters' and PhD students in aero and mech engineering

1. The Combustor
1. Overall Principle of the Gas Turbine Engine
1.1. Generalities and Overall Description
1.2. Components/Modules Technologies Description
1.3. Thermodynamics and Non-reacting Fluid Dynamics

2. Combustor Role, Requirements and Environment
2.1. Overall View
2.2. Design and Requirements
2.3. Combustor, injector and swirler designs

3. Combustor Architectures
3.1. RQL
3.2. LDI
3.3. LPP
3.4. LSI
3.5. LFP

4. Operating Conditions and Flight Envelope 54

2. Premixed Combustion for Combustors
1. Mathematical descriptions
1.1. Governing Equations of Reacting Flows
1.2. G-Equation Formalism
1.3. Decomposition in static and dynamic components

2. Physical-Chemical Description
2.1. Premixed Combustion Overview
2.2. Swirling Flames Overview
2.3. Acoustics Wave-Flame Interactions
2.4. Autoignition
2.5. Blowout
2.6. Chemical Kinetic
2.7. Combustion Noise
2.8. Combustion Instability
2.9. Flame Speed
2.10. Flame Stretch
2.11. Flammability Limits
2.12. Flashback
2.13. Ignition
2.14. Pollutants Emissions
2.15. Turbulent Combustion
2.16. Turbulent Mixing

3. Combustion modes
3.1. Overview
3.2. Pre-vaporized Mode
3.3. Partially Premixed Mode
3.4. Stratified Premixed Mode
3.5. Fully Premixed Mode

4. Effect of operating conditions on premixed combustion and impact on flame
4.1. Current operating conditions
4.2. Fuel, equivalence ratio and power settings engine matching

3. Premixed Swirling Flame Stabilization
1. Mechanisms and processes of stabilization
1.1. Definitions
1.2. Key stabilization mechanisms: local contributors
1.3. Local equivalence ratio
1.4. Flame stretch
1.5. Flame speed versus flow speed
1.6. Reaction rates
1.7. Vorticity
1.8. Temperature, pressure and density (Equation of State)
1.9. Governing equations
1.10. Role and impact of global flow/flame features

2. Framework for flame stabilization study: application
2.1. Numerical procedure
2.2. Statistically steady flame dynamics
3. Theoretical results on flame stabilization and propagation
3.1. Flowfield decomposition and theoretical approach: framework
3.2. Regimes and configurations
3.3. Expressions for laminar and turbulent planar flames in open tubes
3.4. Expressions for the static component of stabilized flame
3.5. Expressions for the dynamic component of stabilized flame
3.6. Swirling flame numerical simulations: results and discussion
3.7. Summary

4. Effect of operating conditions, swirl number and fuel on flame stabilization

4. Transient Combustion
1. Introduction
1.1. Definitions
1.2. Data sciences and data analysis
1.3. Measurements and diagnostics

2. Unsteady Premixed Combustion
2.1. Laminar unsteady premixed combustion
2.2. Turbulent premixed combustion

3. Combustor Engine Transient

4. Configuration Case Study
4.1. Methodology and Numerical Procedure
4.2. Time average versus instantaneous velocity field
4.3. Flashback
4.4. Lean blowout
4.5. Transient to limit cycle

5. Fundamentals mechanisms and link between steady and unsteady combustion)
5.1. Static and dynamic stability link
5.2. Static stability
5.3. Dynamic stability

6. Technologies and control for flame stabilization and combustion instability
6.1. State of the art
6.2. Effect of swirler position
6.3. Effect of geometry
6.4. Effect of operating condition, equivalence ratio and fuel

5. Swirling Flame Dynamic and Combustion Instability
1. Combustor Acoustics
1.1. Combustion instability loop
1.2. Network acoustics model
1.3. Acoustics codes
1.4. Upstream flow modulation versus self-sustained oscillations
1.5. Flow modulation and Navier-Stokes characteristics boundary conditions models (NSCBC)

2. Modulated swirling flames dynamic
2.1. Flame responses
2.2. Flow dynamic mode conversion processes occurring upstream of the flame
2.3. Unsteady flame front dynamics
2.4. Combustion dynamics mechanisms

3. Combustion instability
3.1. Combustion instability prediction
3.2. Coupling and stability criteria
3.3. Longitudinal instabilities
3.4. Tangential instabilities

6. Design and Numerical Simulations Modeling
1. Context and challenges

2. Modeling of flow modulations in numerical simulations
2.1. Introduction
2.2. Combustor Dynamics Modulation Models
2.3. Inlet modulation in an isothermal duct
2.4. Application to a bluff-body stabilized flame
2.5. Conclusions

3. Modeling approaches and assumptions
3.1. Unsteady Reynolds Averaged Navier-Stokes
3.2. Large Eddy Simulations

4. Chemical kinetic

5. Turbulent combustion modeling
5.1. Thickened flame models
5.2. Flamelet models
5.3. Flame surface models
5.4. Probability Density Function models

6. A priori filtering for turbulent combustion model
6.1. Introduction
6.2. The a priori filtering method
6.3. DNS Preccinsta dataset
6.4. Results and discussion
6.5. Comparisons for the Thickened Flame model
6.6. Conclusions and perspectives

7. Fuel vaporization physics and modeling

8. Supercritical combustion regime at take-off conditions

7. Lean Fully Premixed (LFP) Injector Design
1. Design procedure

2. Innovation and concept definition

3. Modeling and sizing
3.1. Vaporizing unit
3.2. Premixing and premixing-stabilizing units

4. Conclusion

Conclusion and Perspectives