1 KNOO Annual Meeting 2008 LES and URANS of Turbulent Flow parallel to PWR and AGR Fuel Rod Bundles...
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Transcript of 1 KNOO Annual Meeting 2008 LES and URANS of Turbulent Flow parallel to PWR and AGR Fuel Rod Bundles...
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KNOO Annual Meeting 2008
LES and URANS of Turbulent Flow parallel to PWR and AGR Fuel Rod
Bundles
S. Rolfo
The University of Manchester, M60 1QD, UKSchool of Mechanical, Aerospace & Civil Engineering.
CFD group
The
Uni
vers
ity
of M
anch
este
r
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RNR-Na assembly (Super Phoenix Reactor).
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Scales separation and levels of approximation.
DNS
LES
RANS
Scales separation and levels of approximation.
Fixed point at which the FFT is evaluated
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Code_Saturne
Code developed by EdF and now open source downloadable from:
http://rd.edf.com/the-edf-offers/research-and-development/softwares/code-
saturne-107008.html
Unstructured
Co-located, Finite Volume Formulation
Different turbulent models (both RANS and LES)
Incompressible or expandable flows with or without heat transfer
Different modules: radiative heat transfer, combustion, magneto-hydrodynamics, compressible flows, two-phase flows
Possible coupling with Code_Aster for structural analysis and with Syrthes for thermal analysis.
Parallel code coupling capabilities (awarded the Gold medal on HPCx)
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Rod Bundle arranged in a triangular array
• Two different geometrical configuration
1. P/D = 1.06
2. P/D = 1.15
• Three different Thermal Hydraulic regimes:
1. P/D = 1.06 @ Re = 6000 with heat transfer (LES)
2. P/D = 1.06 @ Re = 36000 with heat transfer (RSM-URANS)
3. P/D = 1.15 @ Re = 6000 with heat transfer (LES)
A’A
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Flow Pulsation in the mid-plane (P/D = 1.06)
LES @ Re = 6000
URANS @ Re = 39000
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Flow Pulsation in the mid-plane (P/D = 1.06)
URANS
LES
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Power spectra
P/D =1.06 LES @ Re = 6000
Point A Point B
P/D =1.15 LES @ Re = 6000
Point B
P/D =1.06 URANS @ Re = 36000
Point A
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Average Field (LES P/D = 1.06 Re = 6000)
<U> <T>
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Reynolds Stress
<uu>
<vv>
<ww>
<uv>
<uw>
<vw>
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Conclusions and future workFlow Fluctuations in the mid plane of the geometry were successfully detected
for the configuration characterised by P/D = 1.06. However P/D = 1.15 did not show any significant behaviour from channel or pipe flows.
URANS is able to capture the flow fluctuations, however the Reynolds stresses are more similar to those observed at higher P/D.
LES, at low Re number, of larger geometry (two complete sub-channels) to be tested in order to verify the correct prediction of the dominant frequency.
Improved geometry with the addition of a wire, wrapped around the pin (SFR assembly), will be computed.
AcknowledgementsAcknowledgements This work was carried out as part of the TSEC programme KNOO and as such we are
grateful to the EPSRC for funding under grant EP/C549465/1.