dutch openfoam® users group€¦ · cfx post processing paraview ansys boundary conditions solver...

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Consultancy, Design & Engineering

Fluid Dynamics & Heat transfer

Dutch OpenFOAM®Users Group

Validation of elementary flow situations

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• Short introduction FlowMotion

• Elementary examples OpenFOAM


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FlowMotion is an engineering and consultancy company

specialized in fluid dynamics for industrial applications

Consultancy, Design & Engineering

Fluid Dynamics & Heat transfer15 years

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Areas


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AXIAL FANS & PUMPSHVACMACHINESINDUSTRIAL AERODYNAMICSVEHICLE AERODYNAMICS

Areas


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Axial fans

pumps


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HVAC


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MACHINES


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INDUSTRIAL

AERO


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VEHICLE

AERO


Product specifications

Economic

Quiet

Small

Compact

Strong

Material

etc…

Flow

Pressures

Temperatures

Velocities

Mass flow

Heat transfer

Drag

etc…

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Tools


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TOOLS

RFOIL, PROP5

FLUENT

OpenFOAM®

VSAERO

ADMS-URBAN

Literature

Wind tunnel

NO2 (µg/m³)> 5652 - 5648 - 5244 - 4840 - 4436 - 4032 - 3628 - 3224 - 2820 - 24< 20

Figure 4.1b

London 2010 - 20% NO2

Annual average NO2 concentration

Modelled using ADMS-Urban0 5 10 Kilometers


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Clients


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OpenFOAM



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Why should we use OpenFOAM?

Because it is for free?

Because it is easy to install and use?

Because everyone can use it?

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Proven technology?

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OpenFOAM

Validation versus

“Applied Fluid Dynamics Handbook”Robert D. Blevins


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Why validation of elementary flow situations?

• Get used to the OpenFOAM model/method• Results are “known”• Comparison to other codes is easy

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Straight pipe

Validation of elementary flow situationsTypical example

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1. Straight pipe2. Miter bend3. Sharp Edged Orifice4. Gradual Expansion5. Degree Entrance Flush6. Conical Entrance Flush7. Abrupt Expansion8. Abrupt Contraction

Validation of elementary flow situationsCases

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Validation of elementary flow situationsApproach

Pre processingGambit (easy to transport)

SolverOpenFOAM (simpleFOAM)

FluentCFX

Post processingParaviewAnsys

Boundary conditionsSolver settings

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Validation of elementary flow situationsCase 1 : Straight pipe

L/D fully developed at 20 or 40?

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Validation of elementary flow situationsCase 1 : Straight pipe

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Validation of elementary flow situationsCase 2 : Miter bend

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Miter bend

>>10m

>>10m

D=0.1m

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Re

Pa 50m/s

10m/s

1.5m/s

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Velocity 1,5 Error (%) Err.OF.(%) 10 Error (%) Err.OF.(%) 50 Error (%) Err.OF.(%)

Exp Data 17,83 Reference 522 Reference 10037 Reference

OpenFOAM 16,63 -6,73 507 -2,87 9675 -3,61

Fluent 17,25 -3,25 3,48 510 -2,30 0,57 9854 -1,82 1,78

CFX 16,77 -5,95 0,79 502 -3,83 -0,96 9455 -5,80 -2,19



OpenFOAM 16,00 -0,50 464 -1,07 8679 -3,19

Fluent 16,35 1,68 2,18 478 1,92 2,99 8566 -4,45 -1,26

CFX 15,89 -1,18 -0,68 463 -1,28 -0,21 8561 -4,51 -1,32



OpenFOAM 18,45 -4,50 563 -0,88 10791 -1,51

Fluent 19,06 -1,35 3,16 568 0,00 0,88 10636 -2,92 -1,41

CFX 18,11 -6,26 -1,76 563 -0,88 0,00 10921 -0,32 1,19

AVERAGE Error Av. Ref: 3,58%, OpenFOAM with Ref: 3,03% and Error Av. OF:1,52%

40 degrees

80 degrees

120 degrees

Error

Case 2 : Miter bend

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we guide your flows

Validation of elementary flow situationsCase 3 : Sharp edge orifice

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2eorde 0.5d/D

Velocity 1,5 Error (%) Err. OF. (%) 10 Error (%) Err. OF. (%) 50 Error (%) Err. OF. (%)

Exp Data 58 Reference 2354 Reference 55791 Reference

OpenFOAM 40,4 -30,34 1891 -19,67 45266 -18,87

Fluent 49,98 -13,83 16,52 1777 -24,51 -4,84 41190 -26,17 -7,31

CFX 42,05 -27,50 2,84 1718 -27,02 -7,35 43456 -22,11 -3,24

2eorde 0.8d/D



OpenFOAM 17,5 -7,89 537 -3,59 10370 -4,69

Fluent 18,44 -2,95 4,95 540 -3,05 0,54 10217 -6,09 -1,41

CFX 17,14 -9,79 -1,89 528 -5,21 -1,62 10230 -5,97 0,12

AVERAGE Error Av. Ref: 13,77%, OpenFOAM with Ref: 12,89% and Error Av. OF: 3,47%Error

Case 3 : Sharp edge orifice

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Validation of elementary flow situationsCase 4 : Gradual expansion

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Turbulent lowpressure eddy

Case 4 : Gradual expansion

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2eordeVelocity 10 Error (%) Err.OF. (%) 50 Error (%) Err.OF. (%)

Exp Data 103 Reference 1624 Reference

OpenFOAM 103 0,00 1640 0,99Fluent 104 0,97 0,97 1628 0,25 -0,74CFX 103 0,00 0,00 1658 2,09 1,11



OpenFOAM 96 -2,04 1650 1,48Fluent 99 1,02 3,06 1597 -1,78 -3,26CFX 98 0,00 2,04 1597 -1,78 -3,26



OpenFOAM 81 -7,95 1263 -9,79Fluent 80 -9,09 -1,14 1223 -12,64 -2,86CFX 80 -9,09 -1,14 1294 -7,57 2,21AVERAGE Error Av. Ref: 4,89%, OpenFOAM with Ref: 5,41% and Error Av. OF: 2,32%

Error

Case 4 : Gradual expansion

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Validation of elementary flow situationsCase 5 : Degree entrance flush

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Validation of elementary flow situationsCase 5 : Degree entrance flush

Pressure drop described at inlet and outlet

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Pascal 500 Error (%) Err.OF. (%) 12500 Error (%) Err.OF. (%)Exp Data 17,62 Reference 95,30 ReferenceOpenFOAM 16,76 -4,88 91,56 -3,92Fluent 17,13 -2,78 2,10 92,64 -2,79 1,13CFX 17,46 -0,91 3,97 95,18 -0,13 3,80AVERAGE Error Av. Ref: 2,42%, OpenFOAM with Ref: 4,45% and Error Av. OF: 3,1%

Error

Case 5 : Degree entrance flush

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we guide your flows

Validation of elementary flow situationsCase 6 : Conical entrance flush

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Validation of elementary flow situationsCase 6 : Conical entrance flush

Velocity 500 Error (%) Err.OF.(%) 12500 Error(%) Err.OF.(%)Exp Data 18,75 Reference 103 ReferenceOpenFOAM 17,56 -6,35 101,65 -1,31Fluent 19,07 1,71 8,05 106,12 3,03 4,34CFX 19 1,33 7,68 105,84 2,76 4,07

a/D=0,6 ϴ(deg)=55

Velocity 500 Error (%) Err.OF.(%) 12500 Error (%) Err.OF.(%)Exp Data 18,23 Reference 99,3 ReferenceOpenFOAM 17,68 -3,02 96,119 -3,20Fluent 18,33 0,55 3,57 100,84 1,55 4,75CFX 18,2 -0,16 2,85 102,156 2,88 6,08AVERAGE Error Av. Ref: 2,65%, OpenFOAM with Ref: 4.15% and Error Av. OF: 6,03%

a/D=0,1 ϴ(deg)=100

Error

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Validation of elementary flow situationsCase 7 : Abrupt expansion

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2eorde 0.5d/D



OpenFOAM 40,4 -30,34 1891 -19,67 45266 -18,87

Fluent 49,98 -13,83 16,52 1777 -24,51 -4,84 41190 -26,17 -7,31

CFX 42,05 -27,50 2,84 1718 -27,02 -7,35 43456 -22,11 -3,24

2eorde 0.8d/D



OpenFOAM 17,5 -7,89 537 -3,59 10370 -4,69

Fluent 18,44 -2,95 4,95 540 -3,05 0,54 10217 -6,09 -1,41

CFX 17,14 -9,79 -1,89 528 -5,21 -1,62 10230 -5,97 0,12

AVERAGE Error Av. Ref: 13,77%, OpenFOAM with Ref: 12,89% and Error Av. OF: 3,47%Error

Case 7 : Abrupt expansion

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Validation of elementary flow situationsCase 7 : Abrupt contraction

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Validation of elementary flow situationsCase 8: Abrupt contraction

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OpenFOAM 46,11 0,22 1616 3,1 34823 2,79

Fluent 47,32 2,82 2,61 1617 3,1 0,06 34825 2,80 0,01

CFX 45,53 -1,09 -1,30 1582 0,9 -2,17 33961 0,24 -2,54

AVERAGE Error Av. Ref: 2,57%, OpenFOAM with Ref: 3,09% and Error Av. OF: 2,36%

Case 8 : Abrupt contraction

Error

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Conclusions

• 8 different cases are simulated with 3 different CFD solvers

• Performance OpenFOAM comparable with Fluent and CFX

• Errors within engineering range

• Large errors need to to be examined in more detail

• OpenFOAM fairly easy to use

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OpenFOAM course will be facilitated by FlowMotion and the Laboratory of Aero and Hydrodynamics of the TU Delft

Courses will start in fall 2011, visit our website www.flowmotion .nl for more information

dutch openfoam® users group€¦ · cfx post processing paraview ansys boundary conditions solver...

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