Code_Aster
®
Version
5.0
Titrate:
TTLV300 Parallelepiped subjected to a density flux on its faces
Date:
20/09/02
Author (S):
C. DURAND, E. SCREW, F. LEBOUVIER
Key
:
V4.25.300-A
Page:
1/6
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
HT-66/02/001/A
Organization (S):
EDF/AMA, EDF/UTO/LOCATED, Delta CAD
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
V4.25.300 document
TTLV300 - Parallelepiped subjected to a density of
flow on its faces
Summary:
This test results from the validation independent of version 3 in linear transitory thermics.
It is about a voluminal problem represented by a modeling 3D.
The functionalities tested are as follows:
·
voluminal thermal element,
·
transitory algorithm of thermics,
·
limiting conditions: imposed flow.
The results are compared with a three-dimensional analytical solution.
Code_Aster
®
Version
5.0
Titrate:
TTLV300 Parallelepiped subjected to a density flux on its faces
Date:
20/09/02
Author (S):
C. DURAND, E. SCREW, F. LEBOUVIER
Key
:
V4.25.300-A
Page:
2/6
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
HT-66/02/001/A
1
Problem of reference
1.1 Geometry
X
Y
L
1
L
3
L
2
Z
Dimensions of the parallelepiped: 2m X 3.2m X 4m
- L
1
= 1.0 m
- L
2
= 1.6 m
- L
3
= 2.0 m
Not O (0., 0., 0.)
Not H (0.5, 0.8, 1.0)
Not C (1.0, 1.6, 2.0)
O
H
C
1.2
Properties of material
=
1. W/m °C
thermal conductivity
C
p
=
1. J/kg °C
specific heat
1.
kg/m
3
mass
voluminal
1.3
Boundary conditions and loadings
Flow imposed on the 6 faces Q = 0.5 W/m
2
= Q
W
1.4 Conditions
initial
T (T = 0) = 1°C = T
0
Code_Aster
®
Version
5.0
Titrate:
TTLV300 Parallelepiped subjected to a density flux on its faces
Date:
20/09/02
Author (S):
C. DURAND, E. SCREW, F. LEBOUVIER
Key
:
V4.25.300-A
Page:
3/6
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
HT-66/02/001/A
2
Reference solution
2.1
Method of calculation used for the reference solution
(
)
(
)
(
)
(
)
(
)
(
)
T X y Z T
T
Q
T WITH B C
With
I erfc
m
L
X
T
I erfc
m
L
X
T
B
I erfc
m
L
y
T
I erfc
m
L
y
T
C
I erfc
m
L
W
m
m
(,)
.
:
.
.
.
.
.
.
.
.
.
=
+
+ +
=
-
+
+
-
-
=
-
+
+
-
-
=
-
+
=
=
0
1
1
0
2
2
0
3
2
2
1
2
2
1
2
2
1
2
2
1
2
2
1
with
(
)
Z
T
I erfc
m
L
Z
T
C
m
p
2
2
1
2
3
0
.
.
.
.
+
-
-
=
=
The values of reference are obtained with
m
= 1000.
2.2
Results of reference
Temperature at the points: O (0,0,0), H (0.5, 0.8, 1.) and C (1., 1.6, 2.)
2.3
Uncertainty on the solution
Analytical solution.
2.4 References
bibliographical
[1]
Mr. J Chang, L.C Chow, W.S Chang, “Improved alternating direction implicit for solving
transient three dimensional heat dissemination problems ", Numerical Heat Transfer, flight 19, p 69-
84, 1991.
Code_Aster
®
Version
5.0
Titrate:
TTLV300 Parallelepiped subjected to a density flux on its faces
Date:
20/09/02
Author (S):
C. DURAND, E. SCREW, F. LEBOUVIER
Key
:
V4.25.300-A
Page:
4/6
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
HT-66/02/001/A
3 Modeling
With
3.1
Characteristics of modeling
3D (HEXA8, PENTA6)
Modeling 1/8 of the parallelepiped
Mesh:
- 6 elements according to X
- 8 elements following y
- 10 elements according to Z
Limiting conditions:
- faces [ABCD], [BEFC], [DCFG]: Q
W
= 0.5
- faces [ABEO], [AOGD], [OEFG]:
= 0.
Points
X
y
Z
Node
O
0.00
0.00
0.00
N2
H
0.50
0.8
1.00
N409
C
1.00
1.6
2.00
N814
D
C
X
y
L
1
L
3
Z
L
2
With
B
E
G
F
O
H
3
2
L
3.2
Characteristics of the mesh
A number of nodes:
819
A number of meshs and types: 288 HEXA8, 576 PENTA6 (168 QUAD4, 96 TRIA3)
3.3 Functionalities
tested
Controls
AFFE_MODELE
THERMICS
3D
AFFE_CHAR_THER
FLUX_REP
THER_LINEAIRE
TEMP_INIT
VALE
LIST_INST
RECU_CHAMP
INST
3.4 Remarks
The limiting condition
= 0. are implicit on the free edges.
Discretization of time: 36 intervals, between 0 and 10 seconds (of 0.005 S with 1.s by interval).
Code_Aster
®
Version
5.0
Titrate:
TTLV300 Parallelepiped subjected to a density flux on its faces
Date:
20/09/02
Author (S):
C. DURAND, E. SCREW, F. LEBOUVIER
Key
:
V4.25.300-A
Page:
5/6
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
HT-66/02/001/A
4
Results of modeling A
4.1 Values
tested
Identification
Reference
Aster %
difference
Tolerance
Not O
(N2) T = 0.05 S
1.0001
1.00000443
-
0.010
1%
T = 0.1 S
1.00398
1.003172
-
0.080
1%
T = 0.2 S
1.03331
1.03127
-
0.198
1%
T = 0.3 S
1.08533
1.08227
-
0.282
1%
T = 0.5 S
1.23086
1.2266
-
0.345
1%
T = 1. S
1.69979
1.6945
-
0.311
1%
T = 5. S
5.9292
5.9234
-
0.098
1%
T = 10. S
11.242
11.236
-
0.054
1%
Not H
(N409) T = 0.05 S
1.0083
1.006472
-
0.181
1%
T = 0.1 S
1.03819
1.03573
-
0.237
1%
T = 0.2 S
1.12556
1.1229
-
0.235
1%
T = 0.3 S
1.22594
1.2233
-
0.217
1%
T = 0.5 S
1.43580
1.4331
-
0.188
1%
T = 1. S
1.96667
1.9639
-
0.140
1%
T = 5. S
6.2167
6.2139
-
0.045
1%
T = 10. S
11.529
11.526
-
0.023
1%
Not C
(N814) T = 0.05 S
1.3785
1.3726
-
0.429
1%
T = 0.1 S
1.5352
1.5308
-
0.290
1%
T = 0.2 S
1.7572
1.7536
-
0.206
1%
T = 0.3 S
1.9295
1.9261
-
0.176
1%
T = 0.5 S
2.2142
2.2110
-
0.146
1%
T = 1. S
2.8085
2.8054
-
0.112
1%
T = 5. S
7.0792
7.0762
-
0.043
1%
T = 10. S
12.392
12.389
-
0.027
1%
4.2 Parameters
of execution
Version: 5.03
Machine: SGI - ORIGIN 2000 - R12000
Overall dimension memory:
8 megawords
Time CPU To use: 7.07 seconds
Code_Aster
®
Version
5.0
Titrate:
TTLV300 Parallelepiped subjected to a density flux on its faces
Date:
20/09/02
Author (S):
C. DURAND, E. SCREW, F. LEBOUVIER
Key
:
V4.25.300-A
Page:
6/6
Manual of Validation
V4.25 booklet: Transitory thermics of the voluminal structures
HT-66/02/001/A
5
Summary of the results
The results obtained are satisfactory. The maximum change (0.43%), is located on external surface
parallelepiped (Point C) at the moment T weakest. At the end of 10 S, this variation decreases, the maximum
is then of 0.054% (not O: center parallelepiped).
This test made it possible to test in linear transient modeling 3D with meshs HEXA8 and
PENTA6.