High performance heat exchange assembly

• US 6,840,307 B2
• Filed: 03/13/2001
• Issued: 01/11/2005
• Est. Priority Date: 03/14/2000
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Eesley, Gary Lynn, Bhatti, Mohinder Singh, Morelli, Donald T.
• Primary Examiner(s): Bennett, Henry
• Assistant Examiner(s): PATEL, NIHIR B
• Application Number:
  US09/804,756
• Publication Number:
  US 20010032720A1
• Time in Patent Office: 1,400 Days
• Field of Search: 165/80.3, 165/185, 165/905, 165/907
• US Class Current: 165/80.3
• CPC Class Codes: F28F 13/003 by using permeable mass, perforated or porous materials F28F13/18 takes precedence
• CPC Class Codes: F28F 3/02 Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations F28F3/08 takes precedence
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/3677 Wire-like or pin-like cooling fins or heat sinks
• CPC Class Codes: H01L 23/3733 having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures H01L23/3732, H01L23/3737 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 165/905 Materials of manufacture
• CPC Class Codes: Y10S 165/907 Porous
• CPC Class Codes: Y10T 29/49393 with metallurgical bonding

Abstract

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.

Claims

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, $b=0.6498<br><br>\sqrt{\frac{k_f<br><br>{\mathrm{\delta <br><br>}}_f}{h}}$

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/ft² s °

F., and where h is given by the formula, $h=1.2704<br><br>\left[\frac{n^{0<br><br>\text{\hspace{1em}<br><br>}<br><br>50}}{{\left(1-\mathrm{\varphi <br><br>}\right)}^{0.25}}\right]<br><br>\left(\frac{{\mathrm{\rho <br><br>}}^{0<br><br>\text{\hspace{1em}<br><br>}<br><br>50<br><br>\text{\hspace{1em}<br><br>}}<br><br>k^{0.63}<br><br>c_p^{0<br><br>\text{\hspace{1em}<br><br>}<br><br>37}}{{\mathrm{\mu <br><br>}}^{0.13}}\right)<br><br>u_m^{0.50}$

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/ft³

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.

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.

15. A heat sink of claim 7 wherein said fins and said foam blocks are connected to one surface of said heat spreader plate.

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

=Φ

δ

where,

Φ

is between 1 to 6

δ

, ft, is determined by the relation, $\mathrm{\delta <br><br>}=7.32<br><br>\sqrt{\frac{\mathrm{kc}}{\mathrm{\rho <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>c_p<br><br>u_m}}$

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 lb_m/ft³

c_p is the isobaric specific heat of the cooling fluid, Btu/lb_m°

F.

u_m is the mean velocity of the cooling fluid, ft/s.

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 $b=0.6498<br><br>\sqrt{\frac{k_f<br><br>{\mathrm{\delta <br><br>}}_f}{h}}$

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/ft² s °

F., and where h is given by the formula, $h=1.2704<br><br>\left[\frac{n^{0<br><br>\text{\hspace{1em}<br><br>}<br><br>50}}{{\left(1-\mathrm{\varphi <br><br>}\right)}^{0.25}}\right]<br><br>\left(\frac{{\mathrm{\rho <br><br>}}^{0<br><br>\text{\hspace{1em}<br><br>}<br><br>50<br><br>\text{\hspace{1em}<br><br>}}<br><br>k^{0.63}<br><br>c_p^{0<br><br>\text{\hspace{1em}<br><br>}<br><br>37}}{{\mathrm{\mu <br><br>}}^{0.13}}\right)<br><br>u_m^{0.50}$

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, lb_m/ft³

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 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

=Φ

δ

where,

Φ

is between 1 to 6

δ

, ft, is determined by the relation, $\mathrm{\delta <br><br>}=7.32<br><br>\sqrt{\frac{\mathrm{kc}}{\mathrm{\rho <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>c_p<br><br>u_m}}$

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.