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The 22 September 2021 at 14h00

PhD defense: Simon BLANCHARD – “Multi-physics Large-Eddy Simulation of methane oxy-combustion in Liquid Rocket Engines “

Marie LABADENS |  Cerfacs, Toulouse (France) - Salle Séminaires  |  

weblink: https://cerfacs.webex.com/cerfacs/j.php?MTID=mbe382c39536bace01c8637ab916aada7


Combustion in Liquid Rocket Engines (LRE) happens in extreme conditions which imply several multi-physics phenomena. For this reason, numerical simulation is used to predict and thus to optimize the engine performances and lifetime. In particular this thesis focuses on two main aspects: turbulent oxy-combustion in diffusion flames of methane at high pressure, and prediction of wall heat transfers. The Large Eddy Simulation (LES) code AVBP of CERFACS is used.

Despite its lower performances, methane is now preferred to hydrogen for future LRE because of its reduced cost and its practicality both for in terms of usage and storage. For numerical simulation, this propellant raises new questions about how to ignite and stabilize the flame. To do so, developing realistic chemistry is a key step. Reduced finite rate chemistry schemes with about 15 species are derived and tested for high pressure and highly strained counterflow diffusion flames. However, even reduced kinetic schemes are still expensive in the context of industrial LES simulations. Therefore a new integration method for the chemical source terms is proposed in order to run reactive simulations closer to the flow time step. It is found that significant computational cost is spared, while keeping the same result accuracy compared to the classical integration. Finally, in order to develop future turbulent diffusion flame modeling, a study on how the mesh resolution impacts diffusion flames is also performed. The development of reduced chemistry allows to study precisely the influence of chemical reactions at the near-wall region in LRE conditions on the wall heat flux. Periodic turbulent channels are computed to compare the resolved and non-resolved turbulent boundary layer, with or without chemical reactions. Results show that the near-wall reactions may have a real impact on wall heat flux, and that wall models should take into account this effect in the context of wall-modeled LES.

Another study is conducted to determine the impact of the coupling between the sub-grid scale model and the wall-law on the wall fluxes prediction. It is shown that the amount of turbulent viscosity at the near-wall region greatly changes the fluxes. A stochastic-based model is proposed in the case of isothermal simulations, in order to improve the results for two common LES sub-grid scale models, WALE and Sigma.

The developed models and analyses of those test cases are then used for the LES simulation of two test rigs: the supercritical 5-injectors GCH4/GOx from ONERA and the subcritical single-injector GCH4/LOx from TUM. Their study particularly focuses on the flame behavior and the wall heat flux comparison with experiment.


Fabien HALTERProfessor – ICARE, Université d'OrléansReferee
Pierre BOIVINResearch Director

M2P2, Université de Marseille

Michael PFITZNER    Professor – Institut für Thermodynamik, Universität der Bundeswehr MünchenMember
Franck NICOUDProfessor – IMAG, Université de MontpellierMember
Thomas SCHMITT      Research Director

EM2C, Université de Paris-Saclay

Philippe GRENARDResearch Director


Invited member
Miguel MARTIN-BENITOEngineer – CNESInvited member
Didier SAUCEREAU    Engineer – ArianeGroupInvited member
Bénédicte CUENOTSenior Researcher – CERFACSAdvisor



The AVBP code from CERFACS at the heart of three PRACE projects from the 23rd call

CERFACS |  30 September 2021

Cerfacs is involved in three PRACE projects of the 23rd call for which hour allocation runs from 01/10/2021 to 30/09/2022. Researchers from ECL/LMFA UMR5509 (Ecole Centrale de Lyon) and IMFT (UMR 5502) laboratories have earned projects entirely based on the use of the LES solver developed by Cerfacs AVBP and involve the support of experts from the CFD and COOP teams underling the importance and effectiveness of collaborations between French labs and Cerfacs. Alexis Giauque from ECL/LMFA UMR5509 (Ecole Centrale de Lyon) has obtained not only one but two PRACE projects! The first project LESFAN (RA0101, 30 000 000 CPU hours on Irene/Rome TGCC) is based on the use of AVBP in the turbomachinery version to study the generation of noise by a fan of a real airplane engine. The second, PRACE-EDGES (RA0101, 40 000 000 CPU hours on Irene/Rome TGCC) focuses on LES modeling of dens gas in complex geometries. To do so, the LMFA Team has developed advanced thermodynamic closures in AVBP allowing the direct simulation of such flows. Laurent Selle from IMFT (UMR 5502) has received CPU hours for the GASTON project (RA0061, 30 000 000 CPU hours on Marenostrum BSC) which aims to study the structure of hydrogen flames in porous materials. For this, IMFT and Cerfacs will perform coupled simulations considering the reactive flow with AVBP as well as the conduction in the porous medium with AVTP which is known to play an central role in the flame stabilization process.Read more

watch the online contest ”my thesis in 180 sec” organized for Marie Curie actions

CERFACS |  24 September 2021

Next Thursday, Sept 30th the #FallingWallsLab #MSCA research presentation competition will take place, . This is a competition in which 15 researchers compete to deliver the best presentation of their research topic in the format "my thesis in 180 seconds" . Javier Crespo-Anadon, 3rd year PhD student in the CFD team is one of the 15 finalists and he will present this thesis topic: ignition in spinning combustion engines for a reduction in CO2 emissions! You can watch it online on the above website on Sept 30th at 3pm. I encourage you to go to the website and register!  You'll be able to listen to the other participants' pitches and vote for your favorite. Come and see for yourself what kind of research the EU funds!Read more