Metal-based microchannel heat exchangers made by molding replication and assembly

Patent metadata

Field	Value
Publication number	US-2016161195-A1
Application number	US-201615010162-A
Country	US
Kind code	A1
Filing date	Jan 29, 2016
Priority date	Jan 14, 2008
Publication date	Jun 9, 2016
Grant date	—

Abstract

Compression molding of metals is used to make microchannel heat exchangers. Heat transfer can be improved by employing controlled microchannel surface roughness. Flux-free bonding is achieved using a eutectic thin-film intermediate layer. Seals are leak-tight, mechanically strong, and uniform across multiple contact areas. The metal heat exchangers may be mass-produced inexpensively, and are useful for applications including the cooling of computer chips and other high-power electronic devices, air conditioning, refrigeration, condenser plates, radiators, fuel cell heat management, and instant water heating.

First claim

What is claimed:

1 . A process for making a metal microchannel heat exchanger, said process comprising:
forming one or more open microchannels on a surface of a first homogeneous metal piece, wherein at least one of the microchannels has a width between about 30 μm and about 1000 μm, and a depth between about 30 μm and about 1000 μm; providing a second homogeneous metal piece that, when bonded to the first metal piece, will convert one or more open microchannels on the first metal piece into one or more closed microchannels, wherein the one or more closed microchannels are adapted to transport liquid without substantial leakage; providing a eutectic layer or eutectic precursor layer at one or more of the following locations: a surface of the first metal piece, a surface of the second metal piece, or between the first and second metal pieces; simultaneously applying pressure to and heating the first and second metal pieces, wherein: the pressure pushes the first and second metal pieces toward each other, with the eutectic layer or eutectic precursor layer between the first and second metal pieces; the pieces are heated to a temperature at which the eutectic layer or eutectic precursor layer melts, or at which the eutectic layer or eutectic precursor layer interacts with the metal pieces to form a molten eutectic composition between the first and second metal pieces; and the temperature to which the metal pieces are heated is sufficiently below the melting temperature of the first and second metal pieces that no substantial deformation of the one or more microchannels occurs; cooling the first and second metal pieces to a temperature substantially below the eutectic melting temperature, while maintaining the pressure during at least a portion of said cooling; such that the first and second metal pieces fuse together; such that the one or more open microchannels are converted into one or more closed microchannels, wherein the one or more closed microchannels are adapted to transport liquid without substantial leakage; and wherein no substantial blockage of the one or more closed microchannels occurs as a result of said heating, applying pressure, and cooling; and wherein: the one or more closed microchannels are enclosed entirely by the fused first and second metal pieces and eutectic layer; whereby the fused first and second homogeneous pieces and eutectic layer, together with the enclosed one or more closed microchannels, form a microchannel heat exchanger.

2 . The process of claim 1 , wherein the heat exchanger is capable of withstanding an internal pressure in the one or more closed microchannels of 100 atmospheres or greater.

3 . The process of claim 1 , wherein said microchannel-forming step comprises compression molding of one or both metal pieces with a refractory metal mold insert.

4 . The process of claim 1 , wherein at least one of the closed microchannels has a surface roughness between about 3 μm and about 15 μm.

5 . A metal microchannel heat exchanger produced by the process of claim 1 .

6 . The metal microchannel heat exchanger of claim 5 , wherein said first and second homogeneous metal pieces are brazed to one another by said eutectic layer.

7 . The metal microchannel heat exchanger of claim 5 , wherein the one or more closed microchannels comprise a plurality of substantially parallel microchannels.

8 . The metal microchannel heat exchanger of claim 7 , wherein the plurality of substantially parallel microchannels as supplied by a common fluid supply channel.

9 . The metal microchannel heat exchanger of claim 5 , wherein the one or more closed microchannels comprise a meandering microchannel.

10 . The metal microchannel heat exchanger of claim 5 , wherein the one or more closed microchannels discharge into a fluid drain plenum.

11 . The metal microchannel heat exchanger of claim 10 , wherein the one or more closed microchannels comprise at least one microchannel that discharges into the fluid drain plenum via a fluidic transition that widens outward from an end of the at least one microchannel.

12 . The process of claim 1 , wherein the eutectic layer or eutectic precursor layer comprises a eutectic nanocomposite thin film.

13 . The process of claim 12 , wherein a domain size of the eutectic nanocomposite thin film is in a range from about 100 nm to about 400 nm.

14 . The process of claim 12 , wherein flux-free bonding of the first and second metal pieces is achieved using the eutectic nanocomposite thin film.

Assignees

• Meng Wen Jin
• Mei Fanghua
• Univ Louisiana State

Inventors

• Meng Wen Jin
• Mei Fanghua

Classifications

• H10W40/47

  by flowing liquids, e.g. forced water cooling · CPC title

• H10W40/037

  Assembling together parts thereof · CPC title

• H10W40/22

  characterised by their shape, e.g. having conical or cylindrical projections · CPC title

• F28F1/00 Primary

  Tubular elements; Assemblies of tubular elements (specially adapted for movement F28F5/00) · CPC title

• H01L23/3675

  Electricity · mapped topic