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{{ACHeader
|area=2
|number=10
}}
__NOTOC__
=SANDIA Flame D=
==Application Area 2: Combustion==
===Application Challenge AC2-09===
=Abstract=
This document contains the specifications of the Application  Challenge
proposed by the team of the Institute of Thermal Machinery, Częstochowa
University of Technology. This team performed LES  predictions  of  the
Sandia Flame D within the EU-project MOLECULES FP5, Contract N° G4RD-CT-2000-00402.
The computations were performed with  the  BOFFIN-LES  code
developed at Imperial College by the group of Professor W.P. Jones. The
software for the Conditional Moment Closure model used in  calculations
was developed by Professor E. Mastorakos at  Cambridge  University  and
implemented in the BOFFIN-LES code by the  team  of  the  Institute  of
Thermal Machinery.
 
Sandia Flame D is a  widely  used  test  case  for  the  validation  of
numerical models of non-premixed  combustion.  This  flame  is  of  the
flamelet regime type in which  a  scale  separation  appears  i.e.  the
smallest scales of the  turbulent  flow,  the  Kolmogorov  scales,  are
significantly larger than the scales characteristic  for  the  reaction
zone.  Such  a  flame  facilitates  the  study  of  models  of
turbulence/chemistry interaction, allowing to separate the influence of
turbulence  and  turbulence/chemistry  interaction  models  from  the
influence of chemical kinetics models applied. Non-premixed  combustion
is limited by turbulent mixing and dominated by large scale structures.
The quality of unsteady flow dynamics predictions seems to  be  crucial
for the quality of the overall combustion process. Hence,  within  this
document attention is restricted to LES calculations and  neither  RANS
nor URANS predictions are included or analyzed.
 
To evaluate the sensitivity of the  subgrid-scale-modeling  quality  on
turbulent combustion predictions, two subgrid-scale models were tested:
the classical Smagorinsky  model and the  dynamic  version.  Turbulent
mixing features are then transmitted  to  the  reaction  front  through
turbulence/combustion  interaction  models  that  also  influence  the
overall  combustion  process  predictions.  As  turbulence/combustion
interaction model, two different approaches were  studied:  the  simple
and efficient steady flamelet model and the  more  advanced  simplified
Conditional  Moment  Closure-CMC  (In  simplified  CMC  approach,  the
convective terms in physical space were  neglected,  making  the  model
very close to the unsteady flamelet approach).
 
DOAPs for this type of reacting flow are  velocity,  mixture  fraction,
temperature and species concentration  mean  and  fluctuating  profiles
quantified by their local maxima.
<br/>
----
{{ACContribs
|authors=Andrzej Boguslawski, Artur Tyliszczak
|organisation=Częstochowa University of Technology
}}
{{ACHeader
|area=2
|number=10
}}
 
 
© copyright ERCOFTAC 2018
[[Category:Combustion|Sandia Flame D]]

Revision as of 11:51, 9 October 2018

Front Page

Description

Test Data

CFD Simulations

Evaluation

Best Practice Advice

SANDIA Flame D

Application Area 2: Combustion

Application Challenge AC2-09

Abstract

This document contains the specifications of the Application Challenge proposed by the team of the Institute of Thermal Machinery, Częstochowa University of Technology. This team performed LES predictions of the Sandia Flame D within the EU-project MOLECULES FP5, Contract N° G4RD-CT-2000-00402. The computations were performed with the BOFFIN-LES code developed at Imperial College by the group of Professor W.P. Jones. The software for the Conditional Moment Closure model used in calculations was developed by Professor E. Mastorakos at Cambridge University and implemented in the BOFFIN-LES code by the team of the Institute of Thermal Machinery.

Sandia Flame D is a widely used test case for the validation of numerical models of non-premixed combustion. This flame is of the flamelet regime type in which a scale separation appears i.e. the smallest scales of the turbulent flow, the Kolmogorov scales, are significantly larger than the scales characteristic for the reaction zone. Such a flame facilitates the study of models of turbulence/chemistry interaction, allowing to separate the influence of turbulence and turbulence/chemistry interaction models from the influence of chemical kinetics models applied. Non-premixed combustion is limited by turbulent mixing and dominated by large scale structures. The quality of unsteady flow dynamics predictions seems to be crucial for the quality of the overall combustion process. Hence, within this document attention is restricted to LES calculations and neither RANS nor URANS predictions are included or analyzed.

To evaluate the sensitivity of the subgrid-scale-modeling quality on turbulent combustion predictions, two subgrid-scale models were tested: the classical Smagorinsky model and the dynamic version. Turbulent mixing features are then transmitted to the reaction front through turbulence/combustion interaction models that also influence the overall combustion process predictions. As turbulence/combustion interaction model, two different approaches were studied: the simple and efficient steady flamelet model and the more advanced simplified Conditional Moment Closure-CMC (In simplified CMC approach, the convective terms in physical space were neglected, making the model very close to the unsteady flamelet approach).

DOAPs for this type of reacting flow are velocity, mixture fraction, temperature and species concentration mean and fluctuating profiles quantified by their local maxima.



Contributed by: Andrzej Boguslawski, Artur Tyliszczak — Częstochowa University of Technology

Front Page

Description

Test Data

CFD Simulations

Evaluation

Best Practice Advice


© copyright ERCOFTAC 2018