Shaped heat sinks to optimize flow

Patent metadata

Field	Value
Publication number	US-9854704-B2
Application number	US-201414327687-A
Country	US
Kind code	B2
Filing date	Jul 10, 2014
Priority date	Apr 9, 2009
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A heat sink with shape-optimized fins provides for improved heat transfer. Synthetic jets create vortices which enhance heat transfer and cooling of downstream fins, while the shape of the fins limits pressure drop in the flow over the cooling fins.

First claim

What is claimed is:

1. A cooling system comprising:
a base thermally connected to an object to be cooled;
a primary flow generator that provides for a cooling fluid flow across a surface of the base; and
an array of fins thermally coupled to the base, the array of fins comprising:
a first fin having an internal hollow cavity formed therein and at least one downstream orifice to provide fluid communication between the internal hollow cavity and an external environment; and
a second fin disposed downstream of the cooling fluid flow from the first fin; and

a synthetic jet disposed within the internal hollow cavity of the first fin that produces a flow oscillation at the at least one downstream orifice that interacts with the cooling fluid flow to shed thermal boundary layers on the second fin;
wherein the second fin includes a leading edge oriented to face the cooling fluid flow and the flow oscillation, sides, and a downstream end, with each of the leading edge and the sides comprising a closed surface free of openings.

2. The cooling system of claim 1 wherein each of the first and second fins extends in a vertical direction from the base, with the first fin having a first cross-section shape taken in a plane normal to the vertical direction and the second fin having a second cross-section shape taken in the plane normal to the vertical direction.

3. The cooling system of claim 2 wherein the first fin comprises a bifurcated rear surface, with the bifurcated rear surface defining an orifice that extends upstream from the rear surface and that divides the rear surface into two laterally separate portions.

4. The cooling system of claim 1 wherein the first fin and the second fin are disposed such that a chord of the first fin and a chord of the second fin are disposed along a single array line substantially parallel to a bulk motion of the cooling fluid flow.

5. The cooling system of claim 4 wherein the first fin and second fin are spaced longitudinally apart a distance such that the flow oscillation produced by the synthetic jet interacts with the cooling fluid flow to produce a pair of vortices that pass to opposing lateral sides of the second fin.

6. The cooling system of claim 5 wherein the leading edge of the second fin is disposed behind a rear surface of the first fin by a distance between about 80% and about 120% of a maximum lateral width of the first fin.

7. The cooling system of claim 4 wherein the array of fins comprises a first array of fins, and wherein the cooling system further comprises a second array of fins.

8. The cooling system of claim 7 wherein the second array of fins is disposed along an array line parallel to the single array line of the first array of fins.

9. The cooling system of claim 8 wherein fins in the second array of fins are longitudinally offset from the fins in the first array of fins.

10. The cooling system of claim 7 further comprising additional arrays of fins, and wherein the first array of fins, the second array of fins and the additional arrays of fins are positioned in a radial arrangement on the base, with the primary flow generator providing a cooling fluid flow that is blown down at the base from above.

11. The cooling system of claim 1 further comprising a stand-alone synthetic jet disposed upstream from the first fin, the stand-alone synthetic jet producing a flow oscillation that interacts with the cooling fluid flow to shed thermal boundary layers on the first fin.

12. A cooling system comprising:
a heat sink including:
a base thermally connected to an object to be cooled; and
an array of fins thermally coupled to the base; and

a primary flow generator that provides for a cooling fluid flow across the heat sink; and
wherein the array of fins comprises:
a first fin having an internal hollow cavity formed therein and at least one opening on a downstream end thereof to provide fluid communication between the internal hollow cavity and an external environment; and
a second fin disposed downstream of the cooling fluid flow from the first fin;
wherein the first fin includes a synthetic jet disposed within the internal hollow cavity thereof, the synthetic jet producing a flow oscillation out of the at least one opening that interacts with the cooling fluid flow to shed thermal boundary layers on the second fin; and
wherein the second fin includes a leading edge oriented to face the cooling fluid flow and the flow oscillation, sides, and a downstream end, with each of the leading edge and the sides comprising a closed surface free of openings.

13. The cooling system of claim 12 wherein the primary flow generator comprises a fan.

14. The cooling system of claim 12 wherein each of the first and second fins extends in a vertical direction from the base, with the first and second fins each having a cross-section shape taken in a plane normal to the vertical direction and including a leading edge on an upstream side of the fin and a rear surface on a downstream side of the fin.

15. The cooling system of claim 14 wherein the leading edge comprises a curved surface that curves smoothly back from the leading edge on each side out to a maximum lateral width of the fin and then tapers inwardly toward the rear surface.

16. The cooling system of claim 14 wherein the rear surface comprises a bifurcated rear surface, and wherein the bifurcated rear surface defining an opening that extends upstream from the rear surface and that divides the rear surface into two laterally separate portions.

17. The cooling system of claim 12 wherein the first fin and second fin are spaced longitudinally apart a distance such that the flow oscillation produced by the synthetic jet interacts with the cooling fluid flow to produce a pair of vortices that pass to opposing lateral sides of the second fin.

18. A cooling system comprising:
a heat sink including:
a base thermally connected to an object to be cooled; and
a plurality of fins thermally coupled to the base, wherein one or more of the plurality of fins each includes a leading edge, sides, and a downstream end that define an internal hollow cavity, and at least one opening on the downstream end to provide fluid communication between the internal hollow cavity and an external environment;

a synthetic jet disposed within one or more of the plurality of fins, the synthetic jet being disposed within the internal hollow cavity of a respective fin and producing an oscillating fluid flow that is dispersed out of the at least one opening; and
a primary flow generator that provides for a cooling fluid flow across the heat sink;
wherein the plurality of fins includes:
a first fin including an internal hollow cavity formed therein, with a respective synthetic jet positioned in the internal hollow cavity; and
a second fin disposed downstream from the first fin such that the leading edge thereof is oriented to face the oscillating fluid flow from the synthetic jet in the first fin, with the leading edge and the sides of the second fin comprising closed surfaces free of openings;
wherein the oscillating fluid flow produced by the synthetic jet positioned in the first fin interacts with the cooling fluid flow generated by the primary flow generator to shed thermal boundary layers on the second fin.

Assignees

• Gen Electric

Inventors

• Salapakkam Pradeep Chandra Babu
• Li Ri
• Arik Mehmet
• Gerstler William Dwight
• Whalen Bryan Patrick

Classifications

• H10W40/43 Primary

  by flowing gases, e.g. forced air cooling · CPC title

• F28F3/02

  Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations (F28F3/08 takes precedence) · CPC title

• H01L2924/00

  Electricity · mapped topic

• H01L2924/0002

  Electricity · mapped topic

• F28D2021/0029

  Heat sinks · CPC title