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KNOO CFD @ Manchester: Heat transfer test cases. Test Case 1 : Mixed convection in vertically flowing heated pipe (buoyancy aiding or opposing). Problem specifications: Re=2650 Pr=0.71 Wall constant heat flux Boussinesq approximation Heat transfer Regimes: - PowerPoint PPT Presentation
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Test Case 1 :Test Case 1 :Mixed convection in vertically flowing heated pipeMixed convection in vertically flowing heated pipe
(buoyancy aiding or opposing)(buoyancy aiding or opposing)
Problem specifications:
Re=2650
Pr=0.71
Wall constant heat flux
Boussinesq approximation
Heat transfer Regimes:
Gr/Re2=0.000 Forced Convection
Gr/Re2=0.063 Forced/Mixed Convection
Gr/Re2=0.087 Re-Laminarization
Gr/Re2=0.241 Recovery
KNOO CFD @ Manchester: Heat transfer test cases
AGR working schemeAGR working scheme
Relevance to AGR and VHTR
V gradient away from wall=> Turbulence increase
V gradient nearer wall=> Turbulence decrease
buoyancy aidingbuoyancy aiding
buoyancy opposingbuoyancy opposing
Buoyancy aiding or opposing vertical pipe flowBuoyancy aiding or opposing vertical pipe flow
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0.01 0.1 1 10Bo
Nu/Nu
0
Launder & Sharma Model
Cotton & Ismael Model Suga ModelData of Carr et al (1973)DNS of You et al (2003)
Data of Easby (1978)Data of Parlatan et al (1996)
)/( .. 8042534 rPeRGr108Bo ×=
Nu/Nu0 against ‘buoyancy parameter’, [Hall and Jackson ]
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0.01 0.1 1 10Bo
Nu/Nu
0
Launder & Sharma Model (CONVERT)
Large Eddy Simulation (STAR-CD)
Data of Steiner (1971)
Data of Carr et al (1973)
Data of Parlatan et al (1996)
DNS - You et al (2003)
STAR-CD Quasi DNS [Y. Addad ]
" " 1. 6.3 18.
. 0.2 8.8 10.5.
STAR quasi DNS r R z
You et al DNS r R z
φ
φ
+ + +
+ + +
Δ = Δ = Δ =
Δ = Δ = Δ =
)/( .. 8042534 rPeRGr108Bo ×=
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0.01 0.1 1 10Bo
Nu/Nu
0
Launder & Sharma Model (CONVERT)
Suga Non-Linear Eddy Viscosity Model (CONVERT)
k-omega-SST Model (STAR-CD)
k-omega-SST Model (Code_Saturne)
Large Eddy Simulation (STAR-CD)
DNS - You et al (2003)
K-omega not sensitive to buoyancy effect
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0.01 0.1 1 10Bo
Nu/Nu
0
Launder & Sharma Model (CONVERT)
k-omega-SST Model (STAR-CD)
Lien & Durbin v2f Model (STAR-CD)
Manchester v2f Model (Code_Saturne)
Large Eddy Simulation (STAR-CD)
DNS - You et al (2003)
Good predictions by V2F models
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0.01 0.1 1 10
Bo
Nu/Nu
0
Launder & Sharma Model (CONVERT)Cotton & Ismael Model (CONVERT)Suga Non-Linear Eddy Viscosity Model (CONVERT)Lien-Chen-Leschziner k-eps Model (STAR-CD)k-omega-SST Model (STAR-CD)Lien & Durbin v2f Model (STAR-CD)k-omega-SST Model (Code_Saturne)Manchester v2f Model (Code_Saturne)Large Eddy Simulation (STAR-CD)DNS - You et al (2003)
“standard” STAR k-epsilon model (Lien Chen Leschziner)
5
10
15
20
25
DNS of You et
al (2003)Launder &Sharma
(CONVERT)
Cotton & Ismael(CONVERT)Suga NLEVM(CONVERT)Standard k-
epsilon (STAR-
CD)
Lien & Durbinv2f (STAR-CD)Manchester v2f(Code_Saturne)k-omega-SST
(STAR-CD)k-omega-SST
(Code_Saturne)
Large EddySimulation
Cf x 1000 - Nu
Nusselt number
Friction coefficient
Results for Fully-Developed Forced Convection. (no buoyancy)
Expt. of Polyakov & Shindin
Buoyancy aided heated pipe flow
Gr/Re**2 = 0.000Gr/Re**2 = 0.000
Buoyancy aided heated pipe flow
Gr/Re**2 = 0.087 (relaminarization)Gr/Re**2 = 0.087 (relaminarization)
Buoyancy aided heated pipe flow
Gr/Re**2 = 0.087 (relaminarization)Gr/Re**2 = 0.087 (relaminarization)
Buoyancy aided heated pipe flow
Gr/Re**2 = 0.087 (relaminarization)Gr/Re**2 = 0.087 (relaminarization)
Buoyancy aided heated pipe flow
Gr/Re**2 = 0.241 (recovery)Gr/Re**2 = 0.241 (recovery)