Details
| Original language | English |
|---|---|
| Pages (from-to) | 1723-1730 |
| Number of pages | 8 |
| Journal | Proceedings of the Combustion Institute |
| Volume | 32 |
| Issue number | 2 |
| Publication status | Published - 16 Sept 2008 |
| Externally published | Yes |
| Event | 32nd International Symposium on Combustion - Montreal, QC, Canada Duration: 3 Aug 2008 → 8 Aug 2008 |
Abstract
With the dual-plane stereo PIV technique the instantaneous three-dimensional resolved rate-of-strain tensor is directly measured in turbulent premixed flames. Simultaneously, also the instantaneous subgrid scale (SGS) scalar flux is measured with fine resolution, where for the latter term the conditioned particle image velocimetry (CPIV) technique is applied. The subgrid resolution reaches 118 μm, allowing a 9 × 9 resolution of a subgrid filter with width Δ = 1 mm. This combined measurement approach allows the a-priori comparison of models for the SGS scalar flux term with direct measurements which is important for large eddy simulation methods in turbulent premixed flames. Two different flame conditions of a premixed V-shaped turbulent flame are investigated where the turbulence intensity is varied by a factor of nearly three. The instantaneous radial and axial SGS fluxes are compared with the following three models: gradient model with Smagorinsky approach for the turbulent viscosity, Clark model, and extended gradient model with an anisotropy term. None of these models shows a good correlation with the directly measured flux. The anisotropy term alone (being nearly similar to the Clark model) shows, however, a right trend behaviour. An analysis of the data indicates a significant dependency of the experimentally determined SGS flux on the Favre averaged reaction progress (spatially averaged over the SGS area). A relatively simple closure for the SGS flux, which describes the dilatation due to the gasdynamic expansion, and which is a function proportional to (c̄ - c̃), shows a rather good correlation with direct measurement for some of the components. A successful SGS scalar flux model for premixed turbulent flames most likely needs to include at least two different effects.
Keywords
- A-priori test, Conditioned PIV, SGS scalar flux, Subgrid scale models for LES, Turbulent premixed flame
ASJC Scopus subject areas
- Chemical Engineering(all)
- General Chemical Engineering
- Engineering(all)
- Mechanical Engineering
- Chemistry(all)
- Physical and Theoretical Chemistry
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Proceedings of the Combustion Institute, Vol. 32, No. 2, 16.09.2008, p. 1723-1730.
Research output: Contribution to journal › Conference article › Research › peer review
}
TY - JOUR
T1 - Direct evaluation of the subgrid scale scalar flux in turbulent premixed flames with conditioned dual-plane stereo PIV
AU - Pfadler, Sebastian
AU - Kerl, Johannes
AU - Beyrau, Frank
AU - Leipertz, Alfred
AU - Sadiki, Amsini
AU - Scheuerlein, Jörg
AU - Dinkelacker, Friedrich
N1 - Funding information: The authors gratefully acknowledge financial support of this work by the Deutsche Forschungsgemeinschaft (DFG) and the Erlangen Graduate School in Advanced Optical Technologies (SAOT).
PY - 2008/9/16
Y1 - 2008/9/16
N2 - With the dual-plane stereo PIV technique the instantaneous three-dimensional resolved rate-of-strain tensor is directly measured in turbulent premixed flames. Simultaneously, also the instantaneous subgrid scale (SGS) scalar flux is measured with fine resolution, where for the latter term the conditioned particle image velocimetry (CPIV) technique is applied. The subgrid resolution reaches 118 μm, allowing a 9 × 9 resolution of a subgrid filter with width Δ = 1 mm. This combined measurement approach allows the a-priori comparison of models for the SGS scalar flux term with direct measurements which is important for large eddy simulation methods in turbulent premixed flames. Two different flame conditions of a premixed V-shaped turbulent flame are investigated where the turbulence intensity is varied by a factor of nearly three. The instantaneous radial and axial SGS fluxes are compared with the following three models: gradient model with Smagorinsky approach for the turbulent viscosity, Clark model, and extended gradient model with an anisotropy term. None of these models shows a good correlation with the directly measured flux. The anisotropy term alone (being nearly similar to the Clark model) shows, however, a right trend behaviour. An analysis of the data indicates a significant dependency of the experimentally determined SGS flux on the Favre averaged reaction progress (spatially averaged over the SGS area). A relatively simple closure for the SGS flux, which describes the dilatation due to the gasdynamic expansion, and which is a function proportional to (c̄ - c̃), shows a rather good correlation with direct measurement for some of the components. A successful SGS scalar flux model for premixed turbulent flames most likely needs to include at least two different effects.
AB - With the dual-plane stereo PIV technique the instantaneous three-dimensional resolved rate-of-strain tensor is directly measured in turbulent premixed flames. Simultaneously, also the instantaneous subgrid scale (SGS) scalar flux is measured with fine resolution, where for the latter term the conditioned particle image velocimetry (CPIV) technique is applied. The subgrid resolution reaches 118 μm, allowing a 9 × 9 resolution of a subgrid filter with width Δ = 1 mm. This combined measurement approach allows the a-priori comparison of models for the SGS scalar flux term with direct measurements which is important for large eddy simulation methods in turbulent premixed flames. Two different flame conditions of a premixed V-shaped turbulent flame are investigated where the turbulence intensity is varied by a factor of nearly three. The instantaneous radial and axial SGS fluxes are compared with the following three models: gradient model with Smagorinsky approach for the turbulent viscosity, Clark model, and extended gradient model with an anisotropy term. None of these models shows a good correlation with the directly measured flux. The anisotropy term alone (being nearly similar to the Clark model) shows, however, a right trend behaviour. An analysis of the data indicates a significant dependency of the experimentally determined SGS flux on the Favre averaged reaction progress (spatially averaged over the SGS area). A relatively simple closure for the SGS flux, which describes the dilatation due to the gasdynamic expansion, and which is a function proportional to (c̄ - c̃), shows a rather good correlation with direct measurement for some of the components. A successful SGS scalar flux model for premixed turbulent flames most likely needs to include at least two different effects.
KW - A-priori test
KW - Conditioned PIV
KW - SGS scalar flux
KW - Subgrid scale models for LES
KW - Turbulent premixed flame
UR - http://www.scopus.com/inward/record.url?scp=61849115617&partnerID=8YFLogxK
U2 - 10.1016/j.proci.2008.05.027
DO - 10.1016/j.proci.2008.05.027
M3 - Conference article
AN - SCOPUS:61849115617
VL - 32
SP - 1723
EP - 1730
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
SN - 1540-7489
IS - 2
T2 - 32nd International Symposium on Combustion
Y2 - 3 August 2008 through 8 August 2008
ER -