Patent ID: 6840307

Claim:
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, b = 0.6498 ⁢ k f ⁢ δ f h where, k f is the thermal conductivity of the selected fin material, Btu/ft s ° F. δ f 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/ft 2 s ° F., and where h is given by the formula, h = 1.2704 ⁡ [ n 0 ⁢ ⁢ 50 ( 1 - ϕ ) 0.25 ] ⁢ ( ρ 0 ⁢ ⁢ 50 ⁢ ⁢ k 0.63 ⁢ c p 0 ⁢ ⁢ 37 μ 0.13 ) ⁢ u m 0.50 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, lb m /ft 3 k is the thermal conductivity of the cooling fluid, Btu/ft s ° F. c p is the isobaric specific heat of the cooling fluid, Btu/lb m ° F. μ is the dynamic viscosity of the cooling fluid, lb m /ft s u m is the mean velocity of the cooling fluid, ft/s.