초록

Heat sinks are provided that achieve very high convective heat transfer surface per unit volume. These heat sinks comprise a spreader plate, at least two fins and at least one porous reticulated foam block that fills the space between the fins.

대표청구항 ▼

1. A heat sink for electrical or electronic components comprising:a heat spreader plate to which the components to be cooled are connected; at least two heat conducting fins that are positioned substantially parallel to one another and which are connected substantially perpendicular to said heat spr

1. A heat sink for electrical or electronic components comprising:a heat spreader plate to which the components to be cooled are connected; at least two heat conducting fins that are positioned substantially parallel to one another and which are connected substantially perpendicular to said heat spreader plate; at least one foam block that is disposed in the space between parallel fins wherein said block is formed of reticulated foam to define a highly porous, heat conducting, open-celled structure that permits a cooling fluid to flow through said block as the cooling fluid passes across said fins; and said at least one foam block being made from aluminum, copper, graphite, or aluminum-nitride ceramic wherein the fin height, b, is determined by the relationship, where,kf is the thermal conductivity of the selected fin material, Btu/ft s ° F. δf is the fin thickness, ft h is the convective heat transfer coefficient for the foam-filled space bounded by said fins and said heat spreader plate, Btu/ft2 s ° F., and where h is given by the formula, where,h is the linear density of said at least one foam block, pores per ft φ is the porosity of said at least one foam block, expressed as a fraction ρ is the density of the cooling fluid that passes across said fins, lbm/ft3 k is the thermal conductivity of the cooling fluid, Btu/ft s ° F. cp is the isobaric specific heat of the cooling fluid, Btu/lbm ° F. μ is the dynamic viscosity of the cooling fluid, lbm/ft s um is the mean velocity of the cooling fluid, ft/s. 2. A heat sink for electrical or electronic components comprising:a heat spreader plate to which the components to be cooled are connected; at least two heat conducting fins that are positioned substantially parallel to one another and which are connected substantially perpendicular to said heat spreader plate; at least one foam block that is disposed in the space between parallel fins wherein said block is formed of reticulated foam to define a highly porous, heat conducting, open-celled structure that permits a cooling fluid to flow through block as the cooling fluid passes across said fins; and said at least one foam block being made from aluminum, copper, graphite, or aluminum-nitride ceramic wherein the fin spacing, a, is determined by the relationship, α=Φδwhere,Φ is between 1 to 6 δ, ft, is determined by the relation, where,c is the selected fin length in the flow direction, ft k is the thermal conductivity of the cooling fluid that passes across said fins, Btu/ft s ° F. ρ is the density of the cooling fluid lbm/ft3 cp is the isobaric specific heat of the cooling fluid, Btu/lbm° F. um is the mean velocity of the cooling fluid, ft/s. 3. A heat sink of claim 1 wherein said heat spreader plate, said fins and said at least one foam block are made from the same or different thermal conducting materials.4. A heat sink of claim 1 wherein said heat spreader plate and said fins are made from aluminum, copper, graphite or aluminum-nitride ceramic.5. A heat sink of claim 1 wherein said heat spreader plate and said fins are made from aluminum.6. A heat sink of claim 1 wherein said fins and said at least one foam block are connected to one surface of said heat spreader plate.7. A heat sink of claim 1 wherein said at least one foam block is further defined as a plurality of foam blocks.8. A heat sink of claim 7 wherein said fins are connected to said heat spreader plate through thermal bonding.9. A heat sink of claim 7 wherein said fins are connected to said foam blocks through thermal bonding.10. A heat sink of claim 8 wherein said fins are connected to said foam blocks through thermal bonding.11. A heat sink of claim 1 wherein said fins are connected to said heat spreader plate through thermal bonding.12. A heat sink of claim 1 wherein said fins are connected to said at least one foam block through thermal bonding.13. A heat sink of claim 11 wherein said fins are connected to said at least one foam block through thermal bonding.14. A heat sink for electrical or electronic components comprising:a heat spreader plate to which the components to be cooled are connected; at least two heat conducting fins that are positioned substantially parallel to one another and which are connected substantially perpendicular to said heat spreader plate; at least one foam block that is disposed in the space between parallel fins wherein said block is formed of reticulated foam to define a highly porous, heat conducting, open-celled structure that permits a cooling fluid to flow through said block as the cooling fluid passes across said fins; and said at least one foam block being made from aluminum, copper, graphite, or aluminum-nitride ceramic, wherein the fin height, b, is determined by the relationship, and where, kf is the thermal conductivity of the selected fin material, Btu/ft s ° F. δf is the fin thickness, ft h is the convective heat transfer coefficient for the foam-filled space bounded by said fins and said heat spreader plate, Btu/ft2 s ° F., and where h is given by the formula, where,n is the linear density of said at least one foam block, pores per ft φ is the porosity of said at least one foam block, expressed as a fraction ρ is the density of the cooling fluid that passes across said fins, lbm/ft3 k is the thermal conductivity of the cooling fluid, Btu/ft s ° F. cp is the isobaric specific heat of the cooling fluid, Btu/lbm° F. μ is the dynamic viscosity of the cooling fluid, lbm/ft s um is the mean velocity of the cooling fluid, ft/s and a heat spreader plate to which the components to be cooled are connected; at least two heat conducting fins that are positioned substantially parallel to one another and which are connected substantially perpendicular to said heat spreader plate; at least one foam block that is disposed in the space between parallel fins wherein said block is formed of reticulated foam to define a highly porous, heat conducting, open-celled structure that permits a cooling fluid to flow through said block as the cooling fluid passes across said fins; and said at least one foam block being made from aluminum, copper, graphite, or aluminum-nitride ceramic wherein the fin spacing, a, is determined by the relationship, α=Φδwhere,Φ is between 1 to 6 δ, ft, is determined by the relation, where,c is the selected fin length in the flow direction, ft k is the thermal conductivity of the cooling fluid that pas es across said fins, Btu/ft s ° F. ρ is the density of the cooling fluid lbm/ft3 cp is the isobaric specific heat of the cooling fluid, Btu/lbm° F. um is the mean velocity of the cooling fluid, ft/s. 15. A heat sink of claim 7 wherein said fins and said foam blocks are connected to one surface of said heat spreader plate.