Periodic Reporting for period 3 - LEAFINNOX (Development of the Lean Azimuthal Flame as an Innovative aviation gas turbine low-NOX combustion concept)
Reporting period: 2021-07-01 to 2022-06-30
The development of jet engines with lower emissions than today is imperative from an environmental and public health perspective and for maintaining the competitiveness of European aviation industry. To this end, methods to use kerosene while producing lower NOx and particulate emissions are vital and innovations in this area can become very important for engine manufacturers. In addition, using low-carbon fuels is imperative. This project aims at the development of a new liquid fuel combustion concept based on "MILD" combustion principles, where the fuel and the air are significantly diluted with hot combustion products before they mix and burn, hence reducing the generation of pollutants. The particular configuration studied is the "Lean Azimuthal Flame" (LEAF) which has shown good emission reduction characteristics with natural gas. A liquid-fuel LEAF kerosene combustor has been demonstrated for the first time, which also works well with a range of other liquid fuels including Sunstainable Aviation Fuels, and measurements have shown it produces virtually no particulate emissions and very low NOx. The results also include new modelling capabilities that can be used not only for MILD combustion concepts in the future, but also for improved predictions of more conventional combustor concepts such as the Rich-Quench-Lean (RQL) configurations that are the workhorse of NOx reduction technologies at present. In the project, detailed measurements of NOx have demonstrated its low-NOx potential, with single-digit ppm NOx emissions feasible, while a new burner has been developed by the partners and has been tested at high pressures. Finally, the LEAF burner has operated with 100% hydrogen, producing very low NOx, hence promoting the use of this novel technology also for this important zero-carbon fuel. The results are important for aviation as they allow potentially low-soot and low-NOx to be achieved with a range of fuels (fossil kerosene, synthetic kerosene, hydrogen).
The work has proceeded satisfactorily, with the key Deliverable (i.e. the creation of the novel kerosene LEAF combustor) achieved. The partners have collaborated closely and the work has resulted in the following results:
1. A novel, soot-free kerosene flame has been developed. The measurements performed at two separate labs show that the novel kerosene LEAF produces low soot and low NOx and that it has great potential in producing low emissions from kerosene combustion. Further tests in the context of high-pressure demonstrate the smooth operation at a range of conditions, suggesting that this combustor concept is truly of interest to industry for a practical device.
2. Novel ways to measure nanoparticles in gas turbine flames have been developed. The data assembled by the UNINA probe and analysis system in the UCAM conventional (RQL) burner and in the novel kerosene LEAF demonstrate, for the first time, the number of nanoparticles emitted by swirl flames and by kerosene MILD combustion concepts.
3. NOx and soot kinetic models have been implemented in CFD codes that can be used for LEAF but also for conventional combustor systems, hence allowing innovations.
4. 100% SAF and 100% H2 use in the LEAF combustor has been demonstrated, again producing low NOx, hence extending the LEAF concept in low-carbon fuel use in aviation.
The results have been communicated to industry through focused exchanges, presentations to conferences and workshops, and participation to the Technical Reviews. The results have resulted in new projects funded by the EU and are exploited for further projects from industry.
1. A novel, soot-free kerosene flame has been developed. The measurements performed at two separate labs show that the novel kerosene LEAF produces low soot and low NOx and that it has great potential in producing low emissions from kerosene combustion. Further tests in the context of high-pressure demonstrate the smooth operation at a range of conditions, suggesting that this combustor concept is truly of interest to industry for a practical device.
2. Novel ways to measure nanoparticles in gas turbine flames have been developed. The data assembled by the UNINA probe and analysis system in the UCAM conventional (RQL) burner and in the novel kerosene LEAF demonstrate, for the first time, the number of nanoparticles emitted by swirl flames and by kerosene MILD combustion concepts.
3. NOx and soot kinetic models have been implemented in CFD codes that can be used for LEAF but also for conventional combustor systems, hence allowing innovations.
4. 100% SAF and 100% H2 use in the LEAF combustor has been demonstrated, again producing low NOx, hence extending the LEAF concept in low-carbon fuel use in aviation.
The results have been communicated to industry through focused exchanges, presentations to conferences and workshops, and participation to the Technical Reviews. The results have resulted in new projects funded by the EU and are exploited for further projects from industry.
Burning liquid fuels, and especially kerosene, has always been frought with high levels of soot production. It has been demonstrated in LEAFINNOX that the new kerosene LEAF combustor can produce virtually no soot. Measurements also show that the NOx is low. The LEAF concept has also been tested at elevated pressures and with 100% H2. Modelling at various levels of complexity reveal the details of the underlying processes and result in tools that can be used for a range of fuels and combsutor concepts.
Innovations in Low NOx and low soot kerosene combustion has a huge potential for European gas turbine manufacturers and the present project offers a novel combustion system that is promising for practical application. The expected results until the end of the project include: (i) optimised kerosene LEAF combustion system; (ii) guidelines on how to implement LEAF in an aviation jet engine; (iii) new modelling tools for conventional and unconventional gas turbine combustors. These will be welcome by engine manufacturers because they will allow innovations.
Innovations in Low NOx and low soot kerosene combustion has a huge potential for European gas turbine manufacturers and the present project offers a novel combustion system that is promising for practical application. The expected results until the end of the project include: (i) optimised kerosene LEAF combustion system; (ii) guidelines on how to implement LEAF in an aviation jet engine; (iii) new modelling tools for conventional and unconventional gas turbine combustors. These will be welcome by engine manufacturers because they will allow innovations.