초록

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.

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1. A cooling system comprising: a base thermally connected to an object to be cooled;a flow generator that provides for a cooling fluid flow across a surface of the base;a first array of fins thermally coupled to the base, each fin having an internal cavity within the fin, a closed leading edge that

1. A cooling system comprising: a base thermally connected to an object to be cooled;a flow generator that provides for a cooling fluid flow across a surface of the base;a first array of fins thermally coupled to the base, each fin having an internal cavity within the fin, a closed leading edge that faces a direction from which the cooling fluid flow is flowing and that is free of openings, closed sides free of openings, and at least one opening disposed only on a downstream side of the fin relative to the cooling fluid flow that provides fluid communication between the internal cavity and the cooling fluid flow, the first array of fins further comprising: a first fin having a first cross-section shape;a first pulsing synthetic jet disposed within the internal cavity of the first fin;a second fin having a second cross-section shape, 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,wherein the first pulsing synthetic jet produces a flow oscillation at the at least one opening on the first fin and the interaction of the flow oscillation with the cooling fluid flow produces a pair of vortices, a first vortex being shed from a first lateral side of the first fin, and a second vortex being shed from a second lateral side of the first fin, and wherein the first fin and second fin being spaced longitudinally apart such that the first vortex passes to a first lateral side of the second fin and the second vortex passes to a second lateral side of the second fin. 2. A cooling system as in claim 1, wherein the first cross-section is symmetric about the chord of the first fin, and a downstream end of the first cross-section comprises a bifurcated rear surface normal to the chord, and wherein the at least one opening comprises an opening defined by the bifurcated rear surface, the opening extending upstream from the rear surface and dividing the rear surface into two laterally separate portions. 3. A cooling system as in claim 2, wherein the second cross-section is symmetric about the chord of the second fin, and an upstream end of the second cross-section comprises an aerodynamic shape having a leading edge disposed upon the array line and having a rounded surface that is normal to the chord at the leading edge. 4. A cooling system as in claim 3, wherein the leading edge of the second fin is disposed behind the bifurcated rear surface of the first fin by a distance between about 80% and about 120% of the maximum lateral width of the first cross-section. 5. A cooling system as in claim 3, wherein the cross-sections of the first fin and the second fin comprise sides that are parallel to the chord and which connect a downstream portion of the rounded surface with the bifurcated rear surface. 6. A cooling system as in claim 1, further comprising a second array of fins. 7. A cooling system as in claim 6, wherein the second array of fins is disposed along an array line parallel to the array line of the first array of fins. 8. A cooling system as in claim 6, wherein a lateral distance between the array line of the first array of fins and the array line of the second array of fins is between about 170% and 230% of the maximum lateral width of the first cross section. 9. A cooling system as in claim 1, further comprising: a third fin having a third cross-section shape taken in a plane normal to the vertical direction, disposed such that a chord of the third fin lies along the array line;a second pulsing synthetic jet coupled to the internal cavity of the second fin,wherein the second pulsing synthetic jet produces a flow oscillation at the plurality of openings on the second fin and the interaction of the flow oscillation and the cooling fluid flow produces at least a pair of vortices, a third vortex being shed from a first lateral side of the second fin, and a fourth vortex being shed from a second lateral side of the second fin, and wherein the second fin and the third fin being spaced longitudinally apart such that the third vortex passes to a first lateral side of the third fin and the fourth vortex passes to a second lateral side of the third fin. 10. An array of cooling fins disposed in a cooling flow, the array comprising: a plurality of fins disposed upon a base in thermal communication with an object to be cooled, each of the plurality of fins having a cross-section defining a leading edge, a chord, and a width of the fin, wherein the chord of each of the plurality of fins is disposed along an array line that extends parallel to a bulk motion of the cooling flow, each fin comprising: an internal cavity;at least one opening disposed on a downstream side of the fin relative to the cooling flow; anda pulsing synthetic jet disposed within the base or within the internal cavity of the fin;wherein the leading edge of each fin comprises a closed leading edge that faces a direction from which the cooling fluid flow is flowing and that is free of openings, and closed sides free of openings;wherein the pulsing synthetic jet produces a flow oscillation at the at least one opening on each fin, and the interaction of the flow oscillation with the cooling flow produces a pair of vortices, a first vortex being shed from a first lateral side of the fin, and a second vortex being shed from a second lateral side of the fin,wherein each fin is spaced apart longitudinally from an adjacent downstream fin in the array such that the first vortex shed from a fin passes to a first lateral side of the adjacent downstream fin and the second vortex passes to a second lateral side of the adjacent downstream fin. 11. An array as in claim 10, wherein the cross-section is symmetric about the chord of the fin, and a downstream end of the cross-section comprises a bifurcated rear surface normal to the chord, and wherein the at least one opening comprises an opening defined by the bifurcated rear surface, which extends upstream from the rear surface and divides the rear surface into two laterally separate portions. 12. An array as in claim 10, wherein the cross-section is symmetric about the chord of the second fin, and an upstream end of the cross-section comprises an aerodynamic shape having a leading edge disposed upon the array line and having a rounded surface that is normal to the chord at the leading edge. 13. An array as in claim 11, wherein a leading edge of any fin downstream of another fin of the array is disposed behind the bifurcated rear surface of the adjacent upstream fin by a distance between about 80% and about 120% of the maximum lateral width of the fin cross-section. 14. An array as in claim 11, wherein the cross-section of the fin comprises sides that are parallel to the chord and which connect a downstream portion of the rounded surface with the bifurcated rear surface. 15. A cooling system comprising: a flow generator that generates a cooling fluid flow;a plurality of arrays of cooling fins disposed in the cooling flow, wherein each array of cooling fins comprises:a plurality of fins disposed upon a base in thermal communication with an object to be cooled, each of the plurality of fins having a cross-section defining a leading edge, a chord, and a width of the fin, wherein the leading edge is positioned and oriented to face the cooling fluid flow generated by the flow generator and the chord of each of the plurality of fins is disposed along an array line that extends parallel to a bulk motion of the cooling flow, each fin comprising: an internal cavity;at least one opening disposed on a downstream side of the fin relative to the cooling flow;sides extending between the leading edge and the downstream side that are free of openings; anda pulsing synthetic jet disposed within the base or within the internal cavity of the fin;wherein the leading edge comprises a closed surface free of openings, such that the cooling flow is caused to blow past and around the leading edge;wherein the pulsing synthetic jet produces a flow oscillation at the at least one opening on each fin, and the interaction of the flow oscillation with the cooling flow produces a pair of vortices, a first vortex being shed from a first lateral side of the fin, and a second vortex being shed from a second lateral side of the fin; andwherein each fin is spaced longitudinally from an adjacent downstream fin in the array such that the first vortex shed from a fin passes to a first lateral side of the adjacent downstream fin and the second vortex passes to a second lateral side of the adjacent downstream fin. 16. A cooling system as in claim 15, wherein the plurality of arrays has array lines that are parallel to one another. 17. A cooling system as in claim 16, wherein a lateral distance between the array lines of the plurality of arrays is between about 170% and 230% of the maximum lateral width of the cross section.