Cerfacs Enter the world of high performance ...

The 11 March 2016 at 14h00

PhD Defense : Yannis SADOUDI – Numerical simulation of Fan/Nacelle interaction under crosswind conditions

ROGEL |  SALLE DE CONFÉRENCE JEAN-CLAUDE ANDRÉ |  

Abstract:

Inlet design must fulfill geometrical constraints and engine requirements. One of these requirements is the homogeneity of the flow impacting the fan which is quantified by the distortion levels of stagnation pressure. When the airplane is on the ground and ready to take-off, crosswind conditions are critical for the distorsion level. The most critical case is when the wind direction is normal to the engine axis. Subsonic and supersonic separations occur near the inlet lip. The so-created heterogeneity produces an unsteady stress on the fan blades which can lead to surge. Furthermore, short inlets are designed nowadays reducing the distance available for the flow to homogenize before the fan leading to a coupling between the fan and the separated flow region. The aim of this study is to numerically predict the flow in a short inlet under crosswind conditions and to investigate the fan influence on the distortion. First of all, the distortion definition is based on stagnation quantities. Therefore, the stagnation quantities behavior and the numerical parameters influence must be investigated. The behavior of the stagnation quantities near the boundary layer edge is studied with analytical and numerical approaches. The numerical parameters chosen for the inlet simulation come from the so-obtained results obtained. In order to highlight the fan influence on the distortion, two kinds of simulations were proceeded and compared to experimental results : an isolated inlet simulation and a inlet/fan simulation. To correctly predict the distortion, transition has to be be taken into account. Therefore an innovative solution using transport equations is used. As the computation cost for the inlet/fan computation is prohibitive, the decoupling which consists in injecting on a isolated fan the distortion obtained during a isolated inlet computation, is discussed. In fact, crosswind conditions occur when the airplane is on the ground, thus, the ground influence over the inlet distortion is studied for an isolated inlet. Finally, the distortion criterion used in this study has evidenced some strong defects and can be questioned. Another approach of measurement with another criterion definition is investigated.

keywords :

Fan/nacelle interaction, numerical simulation, transition and turbulence, separation and reattachement, compressible and incompressible areas, distortion

Jury:

Pr. Eric Goncalves                 Referee           ISAE-ENSMA institut P’

Pr. Bruno Koobus                  Referee           IMAG Univ. Montpellier

Pr. Nicolas Gourdain             President       ISAE-DAEP

Pr. Bertrand Aupoix              Director          ONERA

M. Jean-François Boussuge  Member         CERFACS

M. Philippe Chanez               Member         SNECMA

NEWS

Thierry Poinsot officially entered the French Academy of Sciences

CERFACS |  8 November 2021

Thierry Poinsot officially entered the French Academy of Sciences on October 12. See presentation here :Read more


The AVBP code from CERFACS at the heart of for 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. Carlos Perez Arroyo from IMFT (UMR 5502) received 16 Mh CPU hours on Joliot-Curie Skylake partition to support his project WONDER.Read more

ALL NEWS