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www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 1/10
Project
TCFD – Comparison with CFX1. Radial Pump: RP01
2. Radial Blower: RB01
Daegone Nam
Daniel Pöscha
CFturbo® GmbH
Unterer Kreuzweg 1
D- 01097 Dresden
Tel. 0351 40790479
December 2016
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 2/10page 2
TCFD – Comparison with CFX
Radial Pump 01BM_RP01
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 3/10page 3
TCFD – Comparison with CFX
1.1 Case settings: Basic
Physical settings (water)
Dynamic viscosity 0.001 [kg/m·s]
Density 998.2 [kg/m3]
Ref. Temperature 293 [K]
Ref. Pressure 101325 [Pa]
Operating conditions
Rotating speed 1470 [rpm]
Flow rate [m3/s]
P1 0.02222
P2 0.03333
P3 0.045
P4 0.05
P5 0.05556
P6 0.06111
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 4/10page 4
TCFD – Comparison with CFX
INT6
INT1
INT4 INT3
INT2
INT5
All multiple interfaces in rotating domain have to be set as AMI-interface
Stage: INT1 – INT6Impeller: INT2 – INT3
1.1 Case settings: Interfaces
STAT
Co2-ROT
INT1-SIDE-2 INT3-SIDE-2
INT5-SIDE-1INT4-SIDE-1 INT2-SIDE-1
Co3-IMP
INT3-SIDE-1
INT2-SIDE-2
Co1-INPIPE
INT1-SIDE-1
INLET
Co4-VOL
INT4-SIDE-2
INT6-SIDE-1
OUTPIPE
INT6-SIDE-2
OULLET
INT5-SIDE-2
INT1
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 5/10page 5
TCFD – Comparison with CFX
1.2 Mesh
2.9 M cells3 prism layers
18.4 M cells5 prism layers
TCFD Mesh Settings Value
Background mesh size 0.01
Co2_refinementSurfaces (SFP patch) 3 4
refinementSurfaces (rests) 1 4
No of Prism layers 3
<TCFD Mesh> <CFX Mesh>
TCFD
CFX-Mesh
Fluent-Mesh
OpenFOAM-Mesh
ICEM
fluentMeshToFoam
Geometry source: OpenFOAM mesh
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TCFD – Comparison with CFX
1.2 Mesh
<TCFD Mesh> <CFX Mesh>
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TCFD – Comparison with CFX
1.3 Result: Total pressure difference - Stage
120.000
130.000
140.000
150.000
160.000
170.000
180.000
190.000
0,020 0,025 0,030 0,035 0,040 0,045 0,050 0,055 0,060 0,065
Δp
tot,
Stag
e[P
a]
Flow rate [m3/s]
CFX
TCFD
TCFD_CFX-MESH
≈ 5.9 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 8/10page 8
TCFD – Comparison with CFX
140.000
150.000
160.000
170.000
180.000
190.000
200.000
210.000
0,020 0,025 0,030 0,035 0,040 0,045 0,050 0,055 0,060 0,065
Δp
tot,
Imp
elle
r[P
a]
Flow rate [m3/s]
CFX
TCFD
TCFD_CFX-MESH
1.3 Result: Total pressure difference - Impeller
≈ 4.7 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 9/10page 9
TCFD – Comparison with CFX
1.3 Result: Static pressure difference - Stage
120.000
130.000
140.000
150.000
160.000
170.000
180.000
190.000
200.000
210.000
0,020 0,025 0,030 0,035 0,040 0,045 0,050 0,055 0,060 0,065
Δp
stat
,Sta
ge[P
a]
Flow rate [m3/s]
CFX
TCFD
TCFD_CFX-MESH
≈ 1.3 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 10/10page 10
TCFD – Comparison with CFX
1.3 Result: Efficiency - Stage
0,45
0,5
0,55
0,6
0,65
0,7
0,75
0,8
0,85
0,020 0,025 0,030 0,035 0,040 0,045 0,050 0,055 0,060 0,065
Effi
cien
cy [
-]
Flow rate [m3/s]
CFX
TCFD
TCFD_CFD-MESH
≈ 3.9 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 11/10page 11
TCFD – Comparison with CFX
1.3 Result: Torque
0.045
0.050
0.055
0.060
0.065
0.070
0.075
0,020 0,025 0,030 0,035 0,040 0,045 0,050 0,055 0,060 0,065
Torq
ue
[N
·m]
Flow rate [m3/s]
CFX
TCFD
TCFD_CFX-MESH
≈ 2.0 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 12/10page 12
TCFD – Comparison with CFX
[Pa][Pa]
Vflowrate: 0.05 [m3/s]
1.3 Result: Static pressure
<TCFD> <CFX>
✓ Treatment of pressure in paraview: pstat = p*density – p@INLET of TCFD + p@INLET of CFX
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 13/10page 13
TCFD – Comparison with CFX
[Pa] [Pa]
1.3 Result: Static pressure
Vflowrate: 0.05 [m3/s]
<TCFD> <CFX>
✓ Treatment of pressure in paraview: pstat = p*density – p@INLET of TCFD + p@INLET of CFX
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 14/10page 14
TCFD – Comparison with CFX
1) AMI interface has to be used for rotating component with Multiple interfaces• mxp setting value: “0“ • Mixing plan interface for multiple interface causes error during the interation
2) TCFD overestimates the total pressure difference compared to result of CFX• Maximum gap in total pressure difference: ~ 6 %
3) The results from TCFD mesh and TCFD simulation with CFX mesh are almost overlapped
4) The cause of the difference with CFX result is not about MESH• 3 % – 6 % gap in result can be caused by difference of solver.
1.4 Summary
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 15/10page 15
TCFD – Comparison with CFX
Radial Blower 01BM_RB01
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TCFD – Comparison with CFX
2.1 Case settings
Physical settings (Air)
Dynamic viscosity 1.831e-05 [kg/m·s]
Ref. Density 1.19 [kg/m3]
Ref. Temperature 293.15 [K]
Ref. Pressure 100000 [Pa]
Compressible Yes
Operating conditions
Rotating speed 82500 [rpm]
Flow rate [m3/s]
P1 0.015
P2 0.016
P3 0.017
P4 0.018
P5 0.020
Flow-In
Flow-Out
StatorImpeller
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 17/10page 17
TCFD – Comparison with CFX
2.1 Case settings
INT1: MixingplaneINT2 : Mixingplane
INT3: AMI
INLET: Volumeflow
OUTLET: Fixied pressure
Pressure settings
Max/Min pressure ± 1,000,000 [Pa]
Outlet pressure 110,000 [Pa]
Initial pressure 100,000 [Pa]
Relaxation factors
Pressure 0.3
Velocity 0.7
Temp. & Turb. 0.1
Density 0.1
Mesh settings
Background mesh size
0.003 (Co1 & Co4)0.0016 (Co3)0.0014 (Co2)
refinementsurface(Diffusor wall)
2 4
Blade cap gap 0.00015 [m]
No. of layers 3
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 18/10page 18
TCFD – Comparison with CFX
2.2 Mesh
3.0 M cells3 prism layers
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 19/10page 19
TCFD – Comparison with CFX
2.3 Result: Total pressure difference - Stage
5000
5500
6000
6500
7000
7500
8000
8500
9000
9500
10000
14 15 16 17 18 19 20 21
Δp
tot,
Sta
ge[P
a]
Flow rate [l/s]
CFX
TCFD
≈ 1.8 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 20/10page 20
TCFD – Comparison with CFX
5000
5500
6000
6500
7000
7500
8000
8500
9000
9500
10000
14 15 16 17 18 19 20 21
Δp
tot,
Imp
[Pa]
Vflowrate [l/s]
CFX
TCFD
2.3 Result: Total pressure difference - Impeller
≈ 1.5 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 21/10page 21
TCFD – Comparison with CFX
5000
5500
6000
6500
7000
7500
8000
8500
9000
14 15 16 17 18 19 20 21
Δp
stat
, Sta
ge[P
a]
Flow rate [l/s]
CFX
TCFD
2.3 Result: Static pressure difference - Stage
≈ 4.2 %
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 22/10page 22
TCFD – Comparison with CFX
0,50
0,55
0,60
0,65
0,70
0,75
0,80
14 15 16 17 18 19 20 21
ηtt
, Sta
ge[-
]
Flow rate [l/s]
CFX
TCFD
2.3 Result: Efficiency - Stage
≈ 1.0%
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 23/10page 23
TCFD – Comparison with CFX
2.3 Result: Torque
0,0160
0,0170
0,0180
0,0190
0,0200
0,0210
0,0220
0,0230
0,0240
14 15 16 17 18 19 20 21
Tq[N
·m]
Flow rate [l/s]
CFX
TCFD
≈ 3.7%
➢ All values area averaged
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 24/10page 24
TCFD – Comparison with CFX
2.3 Result: Static pressure
X-normal cross-section (x=0) Vflowrate: 0.017 m3/s
[Pa] [Pa]
<TCFD> <CFX>
✓ Treatment of pressure in paraview: pstat = p – p@INLET of TCFD + p@INLET of CFX
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 25/10page 25
TCFD – Comparison with CFX
2.3 Result: Static pressure
Z-normal cross-section (z=0.015) Vflowrate: 0.017 m3/s
[Pa] [Pa]<TCFD> <CFX>
✓ Treatment of pressure in paraview: pstat = p – p@INLET of TCFD + p@INLET of CFX
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 26/10page 26
TCFD – Comparison with CFX
<TCFD> <CFX>
2.3 Result: Static pressure
[Pa] [Pa]
Vflowrate: 0.017 m3/s
✓ Treatment of pressure in paraview: pstat = p – p@INLET of TCFD + p@INLET of CFX
www.cfturbo.com© CFturbo® Software & Engineering GmbH Seite 27/10page 27
TCFD – Comparison with CFX
1) Recent version of TCFD supports the Mesh at the clearance• Refinement factors are changed automatically by specifying the length of gap
2) Compressible settings • Pressure setting for outlet should be higher than surroundings• Recommended relaxation factors for fan case:
3) TCFD overestimates the pressure difference and torque compared to result of CFX.• Gap in total pressure difference: 1.5% - 1.8 %
4) TCFD simulation with CFX mesh was not possible • due to the different size of INT2 in each side (different diameter of outlet of
impeller and inlet of diffusor)• Mis-match of each side of interface patch causes high fluctuation of variables
2.4 Summary
p_relaxation 0.2/0.3
U_relaxation 0.5/0.7
Rho_relaxation 0.01/0.1
Turb. & T_relax 0.01/0.1