Evaluation AC2-09: Difference between revisions
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''z/D''=10 is underpredicted. At the distance ''z/D''=30 both models predict | ''z/D''=10 is underpredicted. At the distance ''z/D''=30 both models predict | ||
good velocity decay. As to the mixture fraction both models predict | good velocity decay. As to the mixture fraction both models predict | ||
quite a long distance | quite a long distance ''z/D'' ≤ 16 for which the mixture fraction is unity | ||
while the experiment showed much more intense mixing in this region. As | while the experiment showed much more intense mixing in this region. As | ||
a consequence, at the jet centerline for a distance [pic] the numerical | a consequence, at the jet centerline for a distance [pic] the numerical | ||
Revision as of 09:56, 30 April 2011
SANDIA Flame D
Application Challenge AC2-09 © copyright ERCOFTAC 2024
Comparison of Test Data and CFD
In this section comparisons of the CFD results and test data are organized as follows:
- Comparisons of two different approaches for modeling the turbulence/combustion interaction, namely: steady flamelet model and simplified Conditional Moment Closure (designated as CMC -model in the figures from here on) obtained with the classical Smagorinsky subgrid scale model,
- Comparisons of two subgrid-scale models, namely: classical Smagorinsky subgrid scale model and dynamic Smagorinsky one using the steady flamelet model of turbulence/combustion interaction.
Fig.6. shows mean velocity axial component and mixture fraction along
the centerline for both steady flamelet and CMC approaches. One can see
quite significant discrepancies between both models. Steady flamelet
shows rapid velocity decay in the near field and then the slope is
quite close to the one measured experimentally. On the other hand the
CMC model leads to much smaller velocity decay. The velocity profile
for CMC is closer to experimental data but the slope at the distance
z/D=10 is underpredicted. At the distance z/D=30 both models predict
good velocity decay. As to the mixture fraction both models predict
quite a long distance z/D ≤ 16 for which the mixture fraction is unity
while the experiment showed much more intense mixing in this region. As
a consequence, at the jet centerline for a distance [pic] the numerical
models do not predict reaction and this is reflected in the temperature
profile and combustion products like CO2 shown in Fig.8. However,
further downstream in the fully developed flame the numerical results
are much closer to the experimental data. Especially CMC predicts the
value of temperature maximum and its location with quite high accuracy
(see Fig.7).
Contributed by: Andrzej Boguslawski — Technical University of Częstochowa
© copyright ERCOFTAC 2024