Thermal Simulation of a Power Electronics Cold Plate with a Parametric Design Study

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EVS28

KINTEX, Korea, May 3-6, 2015

Thermal Simulation of a Power Electronics Cold Plate with a

Parametric Design Study

Boris Marovic

Mentor Graphics (Deutschland) GmbH, Germany, [email protected]

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Agenda

I. Intention of This Work II. The Model Overlook III. The Project Definition

IV. The Meshing Technology of FloEFD

V. CAD embedded CFD of a Parametric CATIA V5 Model VI. Results of Parametric Study

VII.Summary on What We’ve Learned

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Intention of This Work

Demonstration of…

I. …the usefulness of parametric CAD models

II. …the application of parametric studies for such models

III. …the efficiency of automated meshing in such cases

IV. …the efficiency of CAD embedded CFD for the design cycle

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The Model Overlook

IGBT module provided by:

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The Model Overlook

Silicon Chip Solder

Copper Ceramic Copper

Solder

Base plate TIM

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The Model Overlook

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Pin-Fin Thickness = Fin Thickness & Pin radius

Pin-Fin Thickness = 1mm

Fin length = 5mm Pin-Fin Thickness = 2mm

Fin length = 15mm

Pin-Fin Thickness = 4mm Fin length = 25mm Pin-Fin Thickness = 1mm

Fin length = 25mm

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The Model Overlook

Parametric and equations for pin and fin spacing of the CATIA V5 model.

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The Project Definition

I. Triple IGBT module assembly on a cold plate design with fins and pins

II. Cold plate material is Aluminum 6061 III. Coolant is Water

IV. IGBT power is 690W (57,5W per IGBT chip) V. Diode power is 480W (40W per Diode chip) VI. IGBT modules consist of various materials

VII. Local mesh on the IGBT module solids and region of the fins and pins

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The Project Definition

I. The Parametric Study Variables (used here):

1. Fin length (5, 15, 25mm) 2. Fin thickness (1, 2, 3, 4mm)

3. Spacing and pattern are defined by equations and will adopt

II. Possible Further Parameter Variables

1. Flow rate (here: constant 1.0 l/s) 2. Coolant temperature (here: constant 20°C) 3. Coolant fluids (gases or liquids) (here: water)

4. Cold plate materials (here: Aluminum 6061)

5. Channel height, width and length (here: const. 10mm, 95mm, 200mm) 6. Pins instead of fins as well as other shapes

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The Project Definition

I. 1^st Project Setup: ~50 min

II. Mesh size for finest fins: Fluid Cells 1,011,456

(5mm x 1mm) Solid Cells 682,501

Partial Cells 871,738

TOTAL 2,565,695

Meshing time: ~9 min 25 sec

III. Mesh size for coarsest fins: Fluid Cells 27,540

(15mm x 4mm) Solid Cells 357,585

Partial Cells 216,832

TOTAL 601,957

Meshing time: ~1 min 15 sec

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The Meshing Technology of FloEFD

I. Cartesian mesh with octree refinement II. Immersed boundary layer type approach¹⁾

III. Special wall functions and turbulence modelling²⁾

Solid Cell

Fluid Cell Partial Cell

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1) Advanced Immersed Boundary Cartesian Meshing Technology in FloEFD™, Mentor Graphics, http://go.mentor.com/2gogl 2) Enhanced Turbulence Modelling in FloEFD™, Mentor Graphics, http://go.mentor.com/2glzd

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CAD embedded CFD of a Parametric CATIA V5 Model

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CAD embedded CFD of a Parametric CATIA V5 Model

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Results of Parametric Study

12 Overall configurations with 3 x 4 parameter variations

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Name Fin length

[mm] Pin-Fin thickness [mm]

Fluid Cells Solid Cells Partial Cells Total Cells Meshing time [s]

Design Point 1 5 4 73,924 386,471 250,986 711,381 90

Design Point 2 15 4 27,540 357,585 216,832 601,957 75

Design Point 3 25 4 27,900 357,593 216,478 601,971 75

Design Point 4 5 3 97,646 390,519 262,808 750,973 95

Design Point 5 25 3 34,515 363,278 222,210 620,003 94

Design Point 6 15 3 34,674 363,175 222,378 620,227 86

Design Point 7 5 2 195,314 432,088 322,833 950,235 132

Design Point 8 25 2 82,309 405,471 270,676 758,456 113

Design Point 9 15 2 82,646 405,202 270,937 758,785 105

Design Point 10 5 1 1,011,456 682,501 871,738 2,565,695 565

Design Point 11 15 1 718,920 612,905 652,373 1,984,198 454

Design Point 12 25 1 642,986 595,872 609,358 1,848,216 289

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Results of Parametric Study

Smallest and largest Mesh

Design Point 2 - 601,957

Design Point 10 - 2,565,695

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Results of Parametric Study

Velocity for hottest and coldest Design Point

Design Point 3

Design Point 10

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Results of Parametric Study

Velocity and streamlines for hottest and coldest Design Point

Design Point 10 Design Point 3

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Results of Parametric Study

Pressure for hottest and coldest Design Point

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Results of Parametric Study

Fluid temperature for hottest and coldest Design Point

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Results of Parametric Study

Surface Plot of the interior of the IGBT for hottest and coldest De sign Point

Design Point 3

26-49˚C Design Point 10

26-43˚C

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Results of Parametric Study

Diagram explanation (next slide)

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Name Fin length

[mm] Pin-Fin thickness [mm]

Design Point 1 5 4

Design Point 2 15 4

Design Point 3 25 4

Design Point 4 5 3

Design Point 5 25 3

Design Point 6 15 3

Design Point 7 5 2

Design Point 8 25 2

Design Point 9 15 2

Design Point 10 5 1

Design Point 11 15 1

Design Point 12 25 1

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Results of Parametric Study

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

Fin length Pin-Fin thickness

IGBT Tav IGBT Tmax Diode Tav Diode Tmax dPt

Design Point 1 Design Point 2 Design Point 3 Design Point 4 Design Point 5 Design Point 6 Design Point 7 Design Point 8 Design Point 9 Design Point 10 Design Point 11 Design Point 12

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Line type = Fin length Line color = Fin thickness

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Summary on What We’ve Learned

I. CAD embedded CFD can leverage full CAD model parametric

II. Cartesian mesh is ideal for automatic meshing with lots of geometry changes during design cycle

III. Parametric studies can help to find optimum design and play with variants to see influence of changes (sensitivity)

IV. Next Step: Geometry optimization with optimization algorithms

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Thank you for your attention!

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