Microtruss based thermal heat spreading structures

• US 9,546,826 B1
• Filed: 01/21/2010
• Issued: 01/17/2017
• Est. Priority Date: 01/21/2010
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Carter, William B., Gross, Adam F., Guinn, Keith V., Jacobsen, Alan J., Kisailus, David
• Primary Examiner(s): RUBY, TRAVIS C
• Application Number:
  US12/691,393
• Time in Patent Office: 2,553 Days
• Field of Search: 165/104.26, 165/104.21, 165/185, 298/900.32, 428/116, 428/304.4, 428/608
• US Class Current: 1/1
• CPC Class Codes: F28D 15/02 in which the medium condenses and evaporates, e.g. heat pipes heat pipes used in solar heat collectors F24S10/95; in radiators F28D1/0226; in nuclear reactors G21C15/257
• CPC Class Codes: F28D 15/0233 the conduits having a particular shape, e.g. non-circular cross-section, annular F28D15/0241, F28D15/0266 take precedence
• CPC Class Codes: F28D 15/046 characterised by the material or the construction of the capillary structure
• CPC Class Codes: H01L 23/427 Cooling by change of state, e.g. use of heat pipes by liquefied gas H01L23/445

Abstract

A heat transport structure is provided having a structural microtruss wick with a thermal transport medium associated with the microtruss wick for thermal energy transport by fluid and vapor transport between a heat source and a heat sink.

Claims

1. A heat spreading structure comprising:

a) a microtruss wick comprising an ordered three dimensional network of continuous interpenetrating microtruss members, the microtruss members constructed to transport fluid through capillary forces;

b) wherein the plurality of microtruss members comprises at least two length scales of microtruss members comprising;

(1) a first plurality of microtruss members;

(2) a second plurality of microtruss members; and

(3) wherein the second plurality of microtruss members are larger than the first plurality of microtruss members such that the first plurality of microtruss members are more closely spaced together than the second plurality of microtruss members;

c) a thermal transport medium associated with the microtruss wick for thermal energy transport by fluid and vapor transport between a heat source and a heat sink;

d) wherein the plurality of first microtruss members form first nodes, and wherein each of the plurality of first microtruss members forming the first nodes extends beyond the first nodes along a same direction so as to form other nodes with others of the plurality of first microtruss members, and wherein the second plurality of microtruss members form second nodes and change direction at each of the second nodes; and

e) wherein the first plurality of microtruss members overlap a part of the second plurality of microtruss members.

2. The heat spreading structure of claim 1, wherein the microtruss wick is coated with a hydrophobic surface modification agent.

3. The heat spreading structure of claim 1, wherein the microtruss wick is coated with a hydrophyllic surface modification agent.

4. The heat spreading structure of claim 1, wherein the microtruss wick is coated with a surface modification agent comprising a metal.

5. The heat spreading structure of claim 4, wherein the metal comprises at least one of Ni, Cu, Au, Ag, or Pt.

6. The heat spreading structure of claim 1, wherein the microtruss wick is coated with a surface modification agent comprising a ceramic.

7. The heat spreading structure of claim 6, wherein the ceramic comprises at least one of SiOC, SiC, Si3N₄, HfC, Cr₃C₂, B₄N, BN, Al₂O₃, TiB₂, TiN, ZrO₂, or TiB₂.

8. The heat spreading structure of claim 1, wherein the microtruss wick is coated with a wicking aid.

9. The heat spreading structure of claim 8, wherein the wicking aid comprises a nanostructure coating.

10. The heat spreading structure of claim 8, wherein the wicking aid comprises a macrostructure coating.

11. The heat spreading structure of claim 1, wherein the microtruss wick comprises microtrusses comprising surface features.

12. The heat spreading structure of claim 11, wherein the surface features of the microtrusses comprise at least one of grooves or channels.

13. The heat spreading structure of claim 1, wherein the microtruss wick comprises at least one of the plurality of first or second microtruss members forming spaces between adjacent individual ones of the at least one of the plurality of first or second microtruss members, and wherein the thermal transport medium is located exterior to the individual ones of the at least one of the first or second microtruss members in the spaces between adjacent individual ones of the plurality of the at least one of the first or second microtruss members.

14. The heat spreading structure of claim 13, wherein the at least one of the first or second microtruss members are constructed to provide capillary wicking.

15. The heat spreading structure of claim 14, wherein the plurality of first or second microtruss members form a microtruss array, wherein the at least one of the plurality of first or second microtruss members forming spaces between adjacent individual ones of the at least one of the plurality of first or second microtruss members such that non-parallel ones of the at least one of the first or second microtruss members are spaced so as to cause fluid wicking through the microtruss array between adjacent ones of the plurality of the at least one of the first or second microtruss members.

16. The heat spreading structure of claim 15, wherein the microtruss wick is coated with a wicking aid.

17. The heat spreading structure of claim 15, wherein the microtruss wick comprises microtrusses comprising surface features.

18. The heat spreading structure of claim 16, wherein the surface features comprise at least one of grooves or channels.

19. The heat spreading structure of claim 14, wherein the plurality of interconnected microtrusses comprise hollow microtrusses.

20. The heat spreading structure of claim 1, wherein the microtruss wick comprises capillary spaces.

21. The heat spreading structure of claim 1, wherein the microtruss wick is constructed to support load.

22. The heat spreading structure of claim 1, wherein the thermal transport medium comprises a phase changing fluid such that the thermal transport medium transfers the thermal energy by evaporation and condensation.

23. The heat spreading structure of claim 1, wherein the microtruss wick is a conductive thermal transport of heat from the thermal source and the thermal transport medium.

24. A heat spreading structure comprising:

a) a structural microtruss wick extending between a heat source and a heat sink, the structural microtruss wick providing support between surfaces of the heat spreading structure the structural microtruss wick comprising an ordered three dimensional network of continuous interpenetrating microtruss members, the microtruss members constructed to transport fluid through capillary forces;

b) a thermal transport medium associated with the structural microtruss wick for transport of thermal energy by fluid and vapor transport; and

c) wherein the ordered three dimensional network of continuous interpenetrating microtruss members comprises a plurality of first microtruss members forming a first node, and wherein each of the plurality of first microtruss members forming the first node extend in a same direction beyond the first node to form other nodes with other first microtruss members and comprising a plurality of second microtruss members forming second nodes and wherein the plurality of second microtruss members change direction at each node, wherein the microtruss wick comprises two length scales of microtruss such that the second plurality of microtruss members are larger than the first plurality of microtruss members such that the first plurality of microtruss members are more closely spaced together than the plurality of second microtruss members, wherein the first plurality of microtruss members overlap a part of the second plurality of microtruss members.

25. The heat spreading structure of claim 24, wherein the heat spreading structure comprises a vapor transport path adjacent the microtruss wick.

26. The heat spreading structure of claim 24, wherein the heat spreading structure comprises a vapor transport path extending through a non-wicking central region of the structural microtruss wick.

27. The heat spreading structure of claim 24, wherein the structural microtruss wick comprises a non-uniform distribution within the thermal plane structure.

28. The heat spreading structure of claim 27, wherein the structural microtruss wick comprises a higher density near a thermal source and a lower density near a thermal sink.

29. The heat spreading structure of claim 27, wherein the structural microtruss wick comprises a higher density near a periphery of the microtruss wick and a lower density near a center of the microtruss wick.

30. The heat spreading structure of claim 24, wherein the structural microtruss wick comprises different length microtruss members.

31. A heat spreading structure comprising:

a) a microtruss wick comprising an ordered three dimensional network of continuous interpenetrating microtruss members, the microtruss members constructed to transport fluid through capillary forces;

b) a thermal transport medium associated with the microtruss wick for thermal energy transport by fluid and vapor transport between a heat source and a heat sink;

c) wherein the continuous interpenetrating microtruss members comprise hollow microtrusses comprising substantially circular cross sections, the hollow microtrusses being interconnected with each other so as to form a continuous hollow space extending therebetween, within the hollow microtrusses, the hollow microtrusses being sized so as to be capable of capillary wicking without additional wicking structures within the hollow microtrusses; and

d) wherein the plurality of microtruss members comprises at least two length scales of microtruss members comprising;

(1) a first plurality of microtruss members;

(2) a second plurality of microtruss members;

(3) wherein the second plurality of microtruss members are larger than the first plurality of microtruss members such that the first plurality of microtruss members are more closely spaced together than the second plurality of microtruss members;

(4) wherein the plurality of first microtruss members form first nodes, and wherein each of the plurality of microtruss members forming the first nodes extend beyond the first nodes along a same direction so as to form other nodes with others of the plurality of first microtruss members, and wherein the second plurality of microtruss members form second nodes and change direction at each of the second nodes; and

(5) wherein the first plurality of microtruss members overlap a part of the second plurality of microtruss members.