Coupling of SERPENT with Fluid Dynamics code ANSYS CFX

Transcription

Coupling of SERPENT with
Fluid Dynamics code ANSYS CFX
Anni Schulze
schulze@lrst.rwth-aachen.de
Content
 Introduction
• Why coupling?
• The overall coupled system
 Simulation of Fluid Dynamics in ANSYS CFX
• Geometry, Mesh, Boundary Conditions, User Fortran
 The coupling itself
• Calling SERPENT
• Coupling scheme
 Summary and „Wishlist“
Anni Schulze
Serpent User Group Meeting
UC Berkeley, November 6th-8th 2013
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Why coupling 3D-codes?
 neutronics and thermal hydraulics are strongly influencing
each other via moderating and temperature feedback
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influence of axial density distribution: ρ = constant
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influence of axial density distribution: ρ = f(z) = f(T,p)
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Why coupling 3D-codes?
 neutronics and thermal hydraulics are strongly
influencing each other via moderating and
temperature feedback
 three-dimensional effects
• spacer grids
• cross flow
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coupled system of ATHLET-CFX-SERPENT
FILL
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TDV
reactor core (CFX)
v, T, ρ,
𝑚
Upper
Plenum
ATHLET
 thermal hydraulic system
code (1D) by GRS
 providing BC arising in
primary circuit to CFX‘s core
geometry
 called by CFX whenever new
BC‘s are needed (timestep)
Lower
Plenum
A, p, v,
ρ, T
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q
ρ, T
core (SERPENT )
reactor core (CFX)
reactor core (CFX)
coupled system of ATHLET-CFX-SERPENT
CFX
 thermal hydraulic code (3D)
 is calling SERPENT to get
power distribution
 providing SERPENT with
distribution of density and
temperature
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Simulation of Fluid Dynamics in ANSYS CFX
1. build up the geometry
2. create the mesh
3. setup simulation conditions
• solid + fluid domains (materials, interfaces)
• inlet + outlet (p, T, v), Heat Source q
4. simulation
• resolving Reynolds-Averaged-NavierStokes equations
• computationally intensive
 only 3x3 pin geometry
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programming inside CFX  coupling with SERPENT
 Setup can be done via User Fortran
• not too easy to handle
• physical quantities inside variable stacks, access via pointers
• Data handling by means of program flow or data controlled
subroutines
 calling SERPENT as a need in heat source data

•
•
•
•
writing Input-file for SERPENT run
running SERPENT (until now, CFX cannot call external solvers)
handling SERPENT output for the needs of CFX
resuming CFX simulation with new heat source data
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CFX  SERPENT: coupling scheme
ANSYS CFX
Memory Management
System
External Script
First call
start CFX
Solver
Read Input &
Mesh
Start of Run
Start of Time Step
(coupleSERPENT.F)
(coupleSERPENT.F)
write Input
file for
SERPENT
Coefficient Loop
Time Step Loop
Start of Coefficient Loop
wait for
SERPENT
Output
Start of linear Solution
Linear
Solution
wait for
SERPENT
Input
run
SERPENT
with NUMPS
edit Output
for CFX
End of linear Solution
End of Coefficient Loop
End of Time Step
(writeHeat.F)
Write
Solution
write results
on heat
source
domain
End of Run
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CFX  SERPENT: geometries
UO2
UO2
UO2
UO2
UO2
UO2
GT
Gd
UO2
y
z
x
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CFX  SERPENT: first outcome
ρ=f(z)
- ρ=const
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ρ=f(x,y,z)
- ρ=f(z)
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CFX  SERPENT: first outcome
Φ𝑡ℎ
T
𝑃𝑓𝑖𝑠𝑠
y
z
x
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Summary and „Wishlist“
 coupling CFX and SERPENT
• coupling in two different languages
• coupling via two (or more) controlling routines
 first outcome
• results make sense from a physics point of view
• computationally intensive !!!
 accelerate SERPENT calculation
• interpolation of density (and temperature) at the beginning
• power distribution in NUMPS only for Uranium zone
• … transient simulations
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Coupling of SERPENT with Fluid Dynamics code ANSYS CFX

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