Periodic Reporting for period 4 - SCIROCCO (Simulation and Control of Renewable COmbustion (SCIROCCO))
Período documentado: 2024-04-01 hasta 2024-09-30
SCIROCCO was lead by Institut de Mecanique des Fluides de Toulouse (IMFT) and CERFACS in Toulouse. It focused on the future hydrogen society and more specifically on what hydrogen developments imply for combustor design. Indeed, while hydrogen may be used in fuel cells (in cars or airplanes for example), its first use will be to burn it and replace fossil fuels in combustors. Green hydrogen will be used in heaters, engines, gas turbines, power generation systems, heavy industry. While such a change of fuel might seem simple, it actually requires significant adaptations to adjust combustors to the specificities of hydrogen. Hydrogen is not 'just another gas'. It differs from other gases such as methane or propane in many ways: hydrogen flames propagate ten times faster than other flames, they ignite much more easily, hydrogen contain 2.5 times more energy than all fossil fuels per kg, lead to dangerous detonations, etc. Existing combustors simply can not work with pure hydrogen and knowing how to modify them is a key question today, both for research and industry.
As as result, two types of studies are mandatory to deploy hydrogen systems on a wide scale in Europe:
- existing combustion systems must be retrofitted and sometimes totally redesigned to use hydrogen
- digital twins are needed for all these systems to design them faster and more efficiently, using powerful computers and novel simulation codes.
In many applications, the evolution towards hydrogen is not viewed as an instantaneous one but might also be done progressively in combustors burning blends of hydrogen and classical fossil fuels, a task which makes combustor design even more complex.
The SCIROCCO's concept was to use a joint experimental / numerical approach combining advanced experiments (performed at IMFT) and sophisticated three-dimensional simulations of unsteady reacting flows (with the simulation tools of CERFACS). This experiment - simulation joint effort was used for small power flames (typically heaters used to heat up water in houses) but also for higher power systems (for example gas turbines for aircraft and helicopters) using hydrogen and hydrogen - methane mixtures. The studies were performed for mixtures of methane and hydrogen and for pure hydrogen flames. The goals were to control flames, ensure that they ignited as expected, produced low levels of pollutants (especially NOx which are the main polluting species for hydrogen flames), did not become unstable or burn the walls of the chambers in which they are stabilized. To reach these objectives, designing new injectors was needed.
As as result, two types of studies are mandatory to deploy hydrogen systems on a wide scale in Europe:
- existing combustion systems must be retrofitted and sometimes totally redesigned to use hydrogen
- digital twins are needed for all these systems to design them faster and more efficiently, using powerful computers and novel simulation codes.
In many applications, the evolution towards hydrogen is not viewed as an instantaneous one but might also be done progressively in combustors burning blends of hydrogen and classical fossil fuels, a task which makes combustor design even more complex.
The SCIROCCO's concept was to use a joint experimental / numerical approach combining advanced experiments (performed at IMFT) and sophisticated three-dimensional simulations of unsteady reacting flows (with the simulation tools of CERFACS). This experiment - simulation joint effort was used for small power flames (typically heaters used to heat up water in houses) but also for higher power systems (for example gas turbines for aircraft and helicopters) using hydrogen and hydrogen - methane mixtures. The studies were performed for mixtures of methane and hydrogen and for pure hydrogen flames. The goals were to control flames, ensure that they ignited as expected, produced low levels of pollutants (especially NOx which are the main polluting species for hydrogen flames), did not become unstable or burn the walls of the chambers in which they are stabilized. To reach these objectives, designing new injectors was needed.
The work done during SCIROCCO proceeded along three main lines:
(1) building laboratories which can host combustion experiments on hydrogen,
(2) building experimental benches in these laboratories for hydrogen flames and
(3) developing digital twins based on simulation for all experimental benches.
Since safety is a key issue for hydrogen, task (1) used a significant part of the project work during the first two years. For all flames, sophisticated diagnostics were then used in three different benches to measure the velocity field, the wall temperatures, the light emission, the production of undesired radicals such as NOx but also the unsteady activity in the chamber when the flame is ignited, when it quenches or when it oscillates.
Using these experimental and numerical tools, the first part of the project focused on small power flames (typical of water heaters) where mixtures of hydrogen and methane were tested in existing combustors but also in innovative configurations where flames were confined in porous media.
During the first two years, a consensus was achieved on the need to focus on pure hydrogen flames because they offer zero CO2 emissions, especially for aerospace applications. This was done for gas turbines in direct relation with SAFRAN. SCIROCCO allowed to design a fully new hydrogen injection system for gas turbines, called HYLON. Since 2020, HYLON has become the hydrogen reference burner for the whole community. The injector was patented with SAFRAN HELICOPTER ENGINES and is one of the short listed concepts tested in France for future hydrogen aircraft engines. HYLON also generated intense interest at other laboratories: it is tested at KAUST (Saudi Arabia), NTNU (Norway), UNIFI (Italy), Orleans (France) and ONERA.
An important outcome of the project is the construction of digital twins for hydrogen combustors, mandatory to speed up developments. SCIROCCO worked intensely on simulation, comparing them and experiments but also making experimental results available worldwide available to the whole world through the TNF (Turbulent Non premixed Flame) workshop (tnfworkshop.org). More than 30 groups use HYLON ERC results to validate their own simulation tools today. Many of them (more than 120) gathered in Toulouse in February 2024 (cerfacs.fr/hydrogenweek) to compare their results.
(1) building laboratories which can host combustion experiments on hydrogen,
(2) building experimental benches in these laboratories for hydrogen flames and
(3) developing digital twins based on simulation for all experimental benches.
Since safety is a key issue for hydrogen, task (1) used a significant part of the project work during the first two years. For all flames, sophisticated diagnostics were then used in three different benches to measure the velocity field, the wall temperatures, the light emission, the production of undesired radicals such as NOx but also the unsteady activity in the chamber when the flame is ignited, when it quenches or when it oscillates.
Using these experimental and numerical tools, the first part of the project focused on small power flames (typical of water heaters) where mixtures of hydrogen and methane were tested in existing combustors but also in innovative configurations where flames were confined in porous media.
During the first two years, a consensus was achieved on the need to focus on pure hydrogen flames because they offer zero CO2 emissions, especially for aerospace applications. This was done for gas turbines in direct relation with SAFRAN. SCIROCCO allowed to design a fully new hydrogen injection system for gas turbines, called HYLON. Since 2020, HYLON has become the hydrogen reference burner for the whole community. The injector was patented with SAFRAN HELICOPTER ENGINES and is one of the short listed concepts tested in France for future hydrogen aircraft engines. HYLON also generated intense interest at other laboratories: it is tested at KAUST (Saudi Arabia), NTNU (Norway), UNIFI (Italy), Orleans (France) and ONERA.
An important outcome of the project is the construction of digital twins for hydrogen combustors, mandatory to speed up developments. SCIROCCO worked intensely on simulation, comparing them and experiments but also making experimental results available worldwide available to the whole world through the TNF (Turbulent Non premixed Flame) workshop (tnfworkshop.org). More than 30 groups use HYLON ERC results to validate their own simulation tools today. Many of them (more than 120) gathered in Toulouse in February 2024 (cerfacs.fr/hydrogenweek) to compare their results.
Beyond the achievements described above, the project has reached other objectives:
- It has allowed to gather world scientists around hydrogen combustion by sharing the HYLON experimental data base : making this data base available to the whole world and creating a new 'hydrogen' academic community has been recognized as a major achievement allowed by the ERC support.
- The initial push produced by SCIROCCO has lead to other prestigious results as SCIROCCO has shown the need for fundamental hydrogen research. Three ERCs are now going on hydrogen in Toulouse: SELECT-H (cerfacs.fr/select-h) a synergy grant called HYROPE and SAFE-H2 (cerfacs.fr/safe-h2) which focuses on safety issues linked to the use of hydrogen, an important side effect of hydrogen dissemination.
- One objective of SCIROCCO was to improve the CFD code AVBP to create digital twins of combustion chambers. This was a success at the academic level and many groups today use AVBP in Europe: TU Berlin, TU Munich, ZHAW in Switzerland, Centrale Lyon, Centralesupelec... More interestingly for dissemination towards industry, the hydrogen version of AVBP has also become the production code to design chambers by engineers at SAFRAN TECH, SAFRAN AIRCRAFT, ARIANEGROUP, SAFRAN HELICOPTER. It is used today to compute combustion chambers for Baker Hughes and Ansaldo in other EU projects (HYPOWERGT, INSIGH2T).
- In terms of society impact, the SCIROCCO researchers have been cited in multiple non scientific journals, highlighting their work for the public.
- In terms of energy policy, the French Academy of Sciences has authored a special report on hydrogen for the president Macron in 2024 (authors: Pr Fontecave, Pr Candel, Dr Poinsot) where SCIROCCO results were used to illustrate the importance of research for hydrogen and discuss its potential.
- In terms of industrial development in the aerospace world, SCIROCCO was ahead of AIRBUS and SAFRAN who both indicated in 2019 that they were not interested in hydrogen. This changed in 2021 leading to fast developments. It changed again in 2025 when Airbus announced that it would slow down. SCIROCCO had a head start which explains why HYLON and the CFD solver AVBP were well received. In the future, even if aerospace applications do not increase, SCIROCCO has allowed to establish multiple other contacts for small burners (with SERMETA), for glass and quartz production (with Saint Gobain), for electricity production (with Baker Hughes in Italy).
- It has allowed to gather world scientists around hydrogen combustion by sharing the HYLON experimental data base : making this data base available to the whole world and creating a new 'hydrogen' academic community has been recognized as a major achievement allowed by the ERC support.
- The initial push produced by SCIROCCO has lead to other prestigious results as SCIROCCO has shown the need for fundamental hydrogen research. Three ERCs are now going on hydrogen in Toulouse: SELECT-H (cerfacs.fr/select-h) a synergy grant called HYROPE and SAFE-H2 (cerfacs.fr/safe-h2) which focuses on safety issues linked to the use of hydrogen, an important side effect of hydrogen dissemination.
- One objective of SCIROCCO was to improve the CFD code AVBP to create digital twins of combustion chambers. This was a success at the academic level and many groups today use AVBP in Europe: TU Berlin, TU Munich, ZHAW in Switzerland, Centrale Lyon, Centralesupelec... More interestingly for dissemination towards industry, the hydrogen version of AVBP has also become the production code to design chambers by engineers at SAFRAN TECH, SAFRAN AIRCRAFT, ARIANEGROUP, SAFRAN HELICOPTER. It is used today to compute combustion chambers for Baker Hughes and Ansaldo in other EU projects (HYPOWERGT, INSIGH2T).
- In terms of society impact, the SCIROCCO researchers have been cited in multiple non scientific journals, highlighting their work for the public.
- In terms of energy policy, the French Academy of Sciences has authored a special report on hydrogen for the president Macron in 2024 (authors: Pr Fontecave, Pr Candel, Dr Poinsot) where SCIROCCO results were used to illustrate the importance of research for hydrogen and discuss its potential.
- In terms of industrial development in the aerospace world, SCIROCCO was ahead of AIRBUS and SAFRAN who both indicated in 2019 that they were not interested in hydrogen. This changed in 2021 leading to fast developments. It changed again in 2025 when Airbus announced that it would slow down. SCIROCCO had a head start which explains why HYLON and the CFD solver AVBP were well received. In the future, even if aerospace applications do not increase, SCIROCCO has allowed to establish multiple other contacts for small burners (with SERMETA), for glass and quartz production (with Saint Gobain), for electricity production (with Baker Hughes in Italy).