Cerfacs Enter the world of high performance ...

The 5 May 2015

PhD Defense: Manqi ZHU – Large Eddy Simulation of thermal cracking in petroleum industry

Marie LABADENS |  CERFACS, Conference room Jean-Claude André |  

Abstract :

To improve the efficiency of thermal-cracking processes, and to reduce the coking phenomena due to high wall temperature, the use of ribbed tubes is an interesting technique as it allows better heat transfer and mixing. However it also induces significant increase of the pressure loss, leading to higher power consumption to push the flow. The complexity of the turbulent flow, the chemical system, and their coupling makes it difficult to estimate a priori the real gain of ribbed tubes in terms of selectivity. Experiments combining turbulence, heat transfer and chemistry are very rare in laboratories and too costly at the industrial scale. In the present work, Wall-Resolved Large Eddy Simulation (WRLES) is used to study firstly non-reacting and then reacting flow in both smooth and ribbed tubes, to reveal the impact of the ribs on the turbulence and chemistry. Simulations were performed with the code AVBP, which solves the compressible Navier-Stokes equations for turbulent flows, using reduced chemistry scheme of ethane and butane cracking for reacting cases.

Special effort was devoted to the wall flow, which is analyzed in detail and compared for both geometries, providing useful information for further development of roughness-type wall modeling. The impact of grid resolution and numerical scheme is also discussed, to find the best trade-off between computational cost and accuracy for industrial application. Results investigate and analyze the turbulent flow structures, as well as the effect of heat transfer efficiency and mixing on the chemical process in both smooth and ribbed tubes. Pressure loss, heat transfer and chemical conversion are finally compared.

Jury :

Kevin VANGEEM                              Gent University                                 Referee

Franck NICOUD                                Université Montpellier 2                   Referee

Laurent JOLY                                    ISAE                                                 Invited member

André NICOLLE                                IFPEN                                              Invited member

Pierre-Alexandre GLAUDE               Université de Lorraine                      Invited member

Philippe RICOUX                              TOTAL                                              Invited member

David JOHN-BROWN                       TOTAL                                              Invited member

Dominique VIENNET                        TOTAL                                              Invited member

Bénédicte CUENOT                          CERFACS                                        Advisor


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