Final Report Summary - TECC-AE (Technologies Enhancement for Clean Combustion in Aero-engines)
Executive Summary:
Due to continuous efforts through past and ongoing European projects, lean combustion by means of internally staged injectors now appears to be the promising technology for obtaining the required emission reductions compatible with a sustainable growth of aviation transport. (cf. ACARE 2020). Recognizing that putting into service such a technology as soon as possible is the only way to effectively reduce the aviation environmental impact, TECC-AE addressed some unavoidable issues in order to:
1. Solve the main limitations identified during past and ongoing projects appearing when lean combustion is pushed toward its maximum potential about NOx emissions reduction. In particular, TECC-AE did:
a. Provide full combustor operability in terms of ignition, altitude relight and weak extinction performance;
b. Suppress the occurrence of thermo-acoustic instabilities by reducing the combustor sensitivity to unsteady features to a level such instabilities did not happen;
2. Ensure injection system robustness with respect to coking that can appear during transient operations of the engine;
3. Optimize the combustion system’s operational and environmental performance through all the flight phases;
4. Develop, demonstrate and validate design rules, CFD capabilities and scaling laws;
5. Provide a global optimization of the multiplicity of combustion parameters of lean combustion systems to achieve lower flame temperatures and thus lower thermal NOx formation.
To look even further ahead and to overcome the complexity issues inherent to staged lean combustors, TECC-AE also focused on the design and assessment of an innovative, compact, lighter and simplified lean combustion combustor concept, and on the development of a compact Ultra Low NOx (ULN) injection system
Project Context and Objectives:
The main objective of the TECC-AE project is to provide the needed and missing design rules as well as innovative technologies to develop an overall staged lean combustion technology with a proven capability to reach the 80% NOx emissions reduction required for introduction into service before 2020 with the necessary reliability, safety and economical viability.
The scientific and technological topics aiming at that goal are:
• To solve the main limitations identified during past and ongoing projects appearing when lean combustion is pushed toward its maximum potential about NOx emissions reduction. In particular, TECC-AE did
• Provide full combustor operability in terms of ignition, altitude relight and weak extinction performance
• Suppress the occurrence of thermo-acoustic instabilities by reducing the combustor sensitivity to unsteady features to a level such instabilities did not happen
• To ensure injection system robustness with respect to coking that can appear during transient operations of the engine.
• To develop, demonstrate and validate design rules, CFD capabilities and scaling laws
• To provide knowledge for global optimization of the multiplicity of combustion parameters of lean combustion systems to achieve lower flame temperatures and thus lower thermal NOx formation (e.g. homogeneous fuel-air mixtures, cooling and unsteady behavior optimization)
To look even further ahead and to overcome the complexity issues inherent to staged lean combustors, the TECC-AE project also had the objective to design and assess an innovative, compact, lighter and simplified lean combustion combustor concept, and to develop a compact Ultra Low NOx (ULN) injection system.
The main outputs derived from the objectives mentioned above are :
• ULN staged and compact injection systems addressing both NOx reduction objectives and operability issues
• Optimised cooling system for gas turbine combustor liner and fuel injection system thermal management.
• Improved techniques to minimise the impact of unsteady flow on the system stability for the ULN injection and combustion systems
• Knowledge, design rules and basic innovative technologies for the design of clean combustion systems capable of ACARE 2020 objectives and for a new compact & simplified combu
Project Results:
See PDF
Potential Impact:
Socio-economic impact
TECC-AE addressed the objective of the transport aeronautics workprogramme to “ensure more environmentally friendly air transport focussing on the greening of the aircraft performance”. TECC-AE made a significant contribution to two of the expected impacts of the AREA 7.1.1.1 Green Aircraft in which the proposal is submitted, namely
- To reduce NOX emissions by 80% in landing and take-off according to ICAO standards and down to 5 g/kg of fuel burnt in cruise,
- To reduce unburnt hydrocarbons and CO emissions by 50% according to ICAO standards
In addition, the purpose of TECC-AE is to deliver such emission reductions while preserving the potential industrial development of such a solution: lightweight, simplicity and cost effectiveness. The expected weight reduction targeted by TECC-AE is also important to reduce fuel consumption and consequently CO2 emissions.
First of all, the demonstration of technology capabilities regarding the impacts has to be fully made and the identified limitations solved. TECC-AE fully supported this objective.
Impacts will be effective only if the technology is largely in service on commercial planes in 2020. Before, it will be necessary to increase the maturity level from 4 at the output of TECCAE to 8 (certification) by mean of others projects (level 2 and level 3). Complementary tests and developments have to be carried out: complete annular combustors tests at high and sub atmospheric pressure, high pressure core test and engine demonstration. For those phases of maturity increase, funding continuity is an essential condition. Some design operations could still occur in order to improve the design while keeping the overall concept unchanged or to scale the technology for integration into different class of engines, using the knowledge and design rules acquired during level 1 projects. TECC-AE contributes directly to this aspect by solving all the remaining unavoidable trade off not addressed by past projects (LOPOCOTEP, TLC, INTELLECT).
After certification, the lean technology has to be largely adopted by airlines. It will be the case if the technology answers to market expectations. Global costs are then to be maintained under control even if market acceptance depends also on regulations, taxes and aviation growth. The more lean technologies will be available with reduced global costs, the more extent they will take within the aeronautical fleet and the bigger the impact on the emissions reduction. Time to market is long in the aeronautic industry: it is crucial to take good decisions regarding design at the beginning of the R&T process to keep global costs (development, acquisition, maintenance and operational costs) under control during all the technology life.
Development costs.
TECC-AE provided answers to the following questions having a big impact on development costs.
Question 1
How to make fully relevant choices for the technological concept to be developed in order to achieve the fixed objectives in terms of operational and environmental performances while controlling induced costs?
Elements of answer provided by TECC-AE
- Identification, quantification and solution of the main limitations of the concepts
- Complete trade off panel solved
Question 2
How to take right decisions during the first iterations of the conception phase with controllable consequences over all the remaining development?
Elements of answer provided by TECC-AE
- Increasing the application field of existing design rules by generating the missing knowledge. Design rules must cover all the aspects in order to get rapid and robust conception avoiding the discovery of problems at the later stage of the process or in production or at worse in service.
Question 3
How to reduce the number and the duration of the design iterations and the number of tests to speed up the whole design process?
Elements of answer provided by TECC-AE
- Increase CFD robustness by application and validation on complex situations
- Extending design rules and design tools to the complete relevant domain
Acquisition costs reduction
Due to the integration of staged combustion functions, clean technologies are usually more complex than the former ones. Complexity mainly comes from the internal architecture of the injection system that makes it difficult to manufacture: production cost increases compared to non Low NOx single annular combustors.
This aspect has been specifically addressed by TECC-AE within the WP5 “Innovative Technologies”. An innovation work has been undertaken with the target of simplifying combustors and injection systems architectures to reduce mass and size while improving operational and environmental performances characteristics. This work led to a simultaneous reduction on acquisition and development costs.
Maintenance costs reduction
Within TECC-AE domain of interest, maintenance costs can be linked to the time taken to change injection systems while the engine is on-wing, to the time taken to change the whole combustor or to the costs to repair the liner of the combustor or some component of the injection system.
The TECC-AE project addressed one potential source, coking, which could be at the origin of some in service maintenance operations. Coking mostly consists of carbon deposit on the wall of the fuel system which perturbs the fuel supply with impacts on the temperature profiles at the combustor exit in such a way that the components turbine life time could be altered.
The robustness of injection systems with respect to coking has been demonstrated through the work done within WP3 “Thermal management”.
Operational costs: Fuel consumption reduction
TECC-AE delivers further reductions in specific fuel consumption through enabling the environmentally acceptable use of higher bypass ratio and overall pressure ratio cycles.
In addition the TECC-AE project addresses the important issue of fuel burn reduction through the development of innovative technologies in view of strongly reducing mass and size of the combustor. As pointed out earlier, strong innovative compact combustor architectures can lead to strong reductions of the total length and mass of the engine, and thus to reduction of fuel burn.
Wider societal implications of the project
Taking into account the evolution of the CAEP standards and societal requirements towards cleaner technologies, TECC-AE output is also a key element in strengthening the competitiveness of the European engine industry.
Compliance with more stringent future international environmental regulations and / or local policies and necessity to meet public expectation concerning environmental issues, are essential challenges for the global aviation. The development of low-emission combustor technology is therefore a pre-requisite for European engine aircraft manufacturers and in particular for the partners of the project to guarantee their competitiveness in the world-wide market, not only in the short term but also in the long term.
TECC-AE will have a major impact on short and long term engine manufacturer competitiveness as it provides:
- An acceleration toward the entry into service for lean technologies based on internally staged injection systems,
- Knowledge and material for optimizing the relevance of the technological strategy developed during the R&T phase to gain excellent performance (operational and environmental ones) while maintaining exploitation costs at market acceptance levels,
- An increase of the technology robustness regarding some vital trade off (NOx emissions reduction / combustor durability, transient operations/ coking, CO-UHC emissions / NOx emissions,
- Knowledge and multi-physics CFD methodology for scaling technology and for doing performance optimization for the whole combustion system ensuring that the product has optimal environmental and operational performance,
- An extension of the acquired knowledge to the whole problematic of lean combustion and its embodiment into more or less automatic system, (which is of vital importance for ensuring that the combustion system is designed with the shortest possible time and fully meets its operational and environmental objective performance).
TECC-AE also reduces corresponding developments costs (20% short term, 50% long term) as compared to former lean combustors (e.g. CFM56 5B DAC combustor).
List of Websites:
Sebastien Roux
SNECMA
Site de Villaroche, Rond-Point René Ravaud - Réau
FRANCE
Phone: +33 1 60 59 71 69
E-mail: sebastien.roux@snecma.fr
TECC-AE public website: www.tecc-project.eu
Due to continuous efforts through past and ongoing European projects, lean combustion by means of internally staged injectors now appears to be the promising technology for obtaining the required emission reductions compatible with a sustainable growth of aviation transport. (cf. ACARE 2020). Recognizing that putting into service such a technology as soon as possible is the only way to effectively reduce the aviation environmental impact, TECC-AE addressed some unavoidable issues in order to:
1. Solve the main limitations identified during past and ongoing projects appearing when lean combustion is pushed toward its maximum potential about NOx emissions reduction. In particular, TECC-AE did:
a. Provide full combustor operability in terms of ignition, altitude relight and weak extinction performance;
b. Suppress the occurrence of thermo-acoustic instabilities by reducing the combustor sensitivity to unsteady features to a level such instabilities did not happen;
2. Ensure injection system robustness with respect to coking that can appear during transient operations of the engine;
3. Optimize the combustion system’s operational and environmental performance through all the flight phases;
4. Develop, demonstrate and validate design rules, CFD capabilities and scaling laws;
5. Provide a global optimization of the multiplicity of combustion parameters of lean combustion systems to achieve lower flame temperatures and thus lower thermal NOx formation.
To look even further ahead and to overcome the complexity issues inherent to staged lean combustors, TECC-AE also focused on the design and assessment of an innovative, compact, lighter and simplified lean combustion combustor concept, and on the development of a compact Ultra Low NOx (ULN) injection system
Project Context and Objectives:
The main objective of the TECC-AE project is to provide the needed and missing design rules as well as innovative technologies to develop an overall staged lean combustion technology with a proven capability to reach the 80% NOx emissions reduction required for introduction into service before 2020 with the necessary reliability, safety and economical viability.
The scientific and technological topics aiming at that goal are:
• To solve the main limitations identified during past and ongoing projects appearing when lean combustion is pushed toward its maximum potential about NOx emissions reduction. In particular, TECC-AE did
• Provide full combustor operability in terms of ignition, altitude relight and weak extinction performance
• Suppress the occurrence of thermo-acoustic instabilities by reducing the combustor sensitivity to unsteady features to a level such instabilities did not happen
• To ensure injection system robustness with respect to coking that can appear during transient operations of the engine.
• To develop, demonstrate and validate design rules, CFD capabilities and scaling laws
• To provide knowledge for global optimization of the multiplicity of combustion parameters of lean combustion systems to achieve lower flame temperatures and thus lower thermal NOx formation (e.g. homogeneous fuel-air mixtures, cooling and unsteady behavior optimization)
To look even further ahead and to overcome the complexity issues inherent to staged lean combustors, the TECC-AE project also had the objective to design and assess an innovative, compact, lighter and simplified lean combustion combustor concept, and to develop a compact Ultra Low NOx (ULN) injection system.
The main outputs derived from the objectives mentioned above are :
• ULN staged and compact injection systems addressing both NOx reduction objectives and operability issues
• Optimised cooling system for gas turbine combustor liner and fuel injection system thermal management.
• Improved techniques to minimise the impact of unsteady flow on the system stability for the ULN injection and combustion systems
• Knowledge, design rules and basic innovative technologies for the design of clean combustion systems capable of ACARE 2020 objectives and for a new compact & simplified combu
Project Results:
See PDF
Potential Impact:
Socio-economic impact
TECC-AE addressed the objective of the transport aeronautics workprogramme to “ensure more environmentally friendly air transport focussing on the greening of the aircraft performance”. TECC-AE made a significant contribution to two of the expected impacts of the AREA 7.1.1.1 Green Aircraft in which the proposal is submitted, namely
- To reduce NOX emissions by 80% in landing and take-off according to ICAO standards and down to 5 g/kg of fuel burnt in cruise,
- To reduce unburnt hydrocarbons and CO emissions by 50% according to ICAO standards
In addition, the purpose of TECC-AE is to deliver such emission reductions while preserving the potential industrial development of such a solution: lightweight, simplicity and cost effectiveness. The expected weight reduction targeted by TECC-AE is also important to reduce fuel consumption and consequently CO2 emissions.
First of all, the demonstration of technology capabilities regarding the impacts has to be fully made and the identified limitations solved. TECC-AE fully supported this objective.
Impacts will be effective only if the technology is largely in service on commercial planes in 2020. Before, it will be necessary to increase the maturity level from 4 at the output of TECCAE to 8 (certification) by mean of others projects (level 2 and level 3). Complementary tests and developments have to be carried out: complete annular combustors tests at high and sub atmospheric pressure, high pressure core test and engine demonstration. For those phases of maturity increase, funding continuity is an essential condition. Some design operations could still occur in order to improve the design while keeping the overall concept unchanged or to scale the technology for integration into different class of engines, using the knowledge and design rules acquired during level 1 projects. TECC-AE contributes directly to this aspect by solving all the remaining unavoidable trade off not addressed by past projects (LOPOCOTEP, TLC, INTELLECT).
After certification, the lean technology has to be largely adopted by airlines. It will be the case if the technology answers to market expectations. Global costs are then to be maintained under control even if market acceptance depends also on regulations, taxes and aviation growth. The more lean technologies will be available with reduced global costs, the more extent they will take within the aeronautical fleet and the bigger the impact on the emissions reduction. Time to market is long in the aeronautic industry: it is crucial to take good decisions regarding design at the beginning of the R&T process to keep global costs (development, acquisition, maintenance and operational costs) under control during all the technology life.
Development costs.
TECC-AE provided answers to the following questions having a big impact on development costs.
Question 1
How to make fully relevant choices for the technological concept to be developed in order to achieve the fixed objectives in terms of operational and environmental performances while controlling induced costs?
Elements of answer provided by TECC-AE
- Identification, quantification and solution of the main limitations of the concepts
- Complete trade off panel solved
Question 2
How to take right decisions during the first iterations of the conception phase with controllable consequences over all the remaining development?
Elements of answer provided by TECC-AE
- Increasing the application field of existing design rules by generating the missing knowledge. Design rules must cover all the aspects in order to get rapid and robust conception avoiding the discovery of problems at the later stage of the process or in production or at worse in service.
Question 3
How to reduce the number and the duration of the design iterations and the number of tests to speed up the whole design process?
Elements of answer provided by TECC-AE
- Increase CFD robustness by application and validation on complex situations
- Extending design rules and design tools to the complete relevant domain
Acquisition costs reduction
Due to the integration of staged combustion functions, clean technologies are usually more complex than the former ones. Complexity mainly comes from the internal architecture of the injection system that makes it difficult to manufacture: production cost increases compared to non Low NOx single annular combustors.
This aspect has been specifically addressed by TECC-AE within the WP5 “Innovative Technologies”. An innovation work has been undertaken with the target of simplifying combustors and injection systems architectures to reduce mass and size while improving operational and environmental performances characteristics. This work led to a simultaneous reduction on acquisition and development costs.
Maintenance costs reduction
Within TECC-AE domain of interest, maintenance costs can be linked to the time taken to change injection systems while the engine is on-wing, to the time taken to change the whole combustor or to the costs to repair the liner of the combustor or some component of the injection system.
The TECC-AE project addressed one potential source, coking, which could be at the origin of some in service maintenance operations. Coking mostly consists of carbon deposit on the wall of the fuel system which perturbs the fuel supply with impacts on the temperature profiles at the combustor exit in such a way that the components turbine life time could be altered.
The robustness of injection systems with respect to coking has been demonstrated through the work done within WP3 “Thermal management”.
Operational costs: Fuel consumption reduction
TECC-AE delivers further reductions in specific fuel consumption through enabling the environmentally acceptable use of higher bypass ratio and overall pressure ratio cycles.
In addition the TECC-AE project addresses the important issue of fuel burn reduction through the development of innovative technologies in view of strongly reducing mass and size of the combustor. As pointed out earlier, strong innovative compact combustor architectures can lead to strong reductions of the total length and mass of the engine, and thus to reduction of fuel burn.
Wider societal implications of the project
Taking into account the evolution of the CAEP standards and societal requirements towards cleaner technologies, TECC-AE output is also a key element in strengthening the competitiveness of the European engine industry.
Compliance with more stringent future international environmental regulations and / or local policies and necessity to meet public expectation concerning environmental issues, are essential challenges for the global aviation. The development of low-emission combustor technology is therefore a pre-requisite for European engine aircraft manufacturers and in particular for the partners of the project to guarantee their competitiveness in the world-wide market, not only in the short term but also in the long term.
TECC-AE will have a major impact on short and long term engine manufacturer competitiveness as it provides:
- An acceleration toward the entry into service for lean technologies based on internally staged injection systems,
- Knowledge and material for optimizing the relevance of the technological strategy developed during the R&T phase to gain excellent performance (operational and environmental ones) while maintaining exploitation costs at market acceptance levels,
- An increase of the technology robustness regarding some vital trade off (NOx emissions reduction / combustor durability, transient operations/ coking, CO-UHC emissions / NOx emissions,
- Knowledge and multi-physics CFD methodology for scaling technology and for doing performance optimization for the whole combustion system ensuring that the product has optimal environmental and operational performance,
- An extension of the acquired knowledge to the whole problematic of lean combustion and its embodiment into more or less automatic system, (which is of vital importance for ensuring that the combustion system is designed with the shortest possible time and fully meets its operational and environmental objective performance).
TECC-AE also reduces corresponding developments costs (20% short term, 50% long term) as compared to former lean combustors (e.g. CFM56 5B DAC combustor).
List of Websites:
Sebastien Roux
SNECMA
Site de Villaroche, Rond-Point René Ravaud - Réau
FRANCE
Phone: +33 1 60 59 71 69
E-mail: sebastien.roux@snecma.fr
TECC-AE public website: www.tecc-project.eu