Cryocooler regenerator containing one or more carbon-based anisotropic thermal layers

Patent metadata

Field	Value
Publication number	US-9488389-B2
Application number	US-201414151408-A
Country	US
Kind code	B2
Filing date	Jan 9, 2014
Priority date	Jan 9, 2014
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

An apparatus includes a regenerator configured to transfer heat to a fluid and to absorb heat from the fluid as the fluid flows between a warm end and a cold end of a cryocooler. The regenerator includes an anisotropic thermal layer configured to reduce a flow of heat axially along the regenerator and to spread the absorbed heat radially or laterally in a plane of the anisotropic thermal layer. The anisotropic thermal layer includes at least one allotropic form of carbon. The anisotropic thermal layer could have a higher radial or lateral thermal conductivity and a lower axial thermal conductivity. The anisotropic thermal layer could include carbon nanotubes and/or graphene. The regenerator could include multiple anisotropic thermal layers that divide the regenerator into multiple segments, where the anisotropic thermal layers are configured to reduce heat transfer between adjacent segments of the regenerator.

First claim

What is claimed is:

1. An apparatus comprising:
a regenerator configured to transfer heat to a fluid and to absorb heat from the fluid as the fluid flows between a warm end and a cold end of a cryocooler;
wherein the regenerator comprises:
multiple anisotropic thermal layers, each of the anisotropic thermal layers comprising a film configured to reduce a flow of heat axially along the regenerator and to spread the absorbed heat radially or laterally in a plane of that anisotropic thermal layer, each of the anisotropic thermal layers comprising at least one allotropic form of carbon, and
one or more support layers configured to structurally support at least one of the anisotropic thermal layers.

2. The apparatus of claim 1 , wherein each of the anisotropic thermal layers has a higher radial or lateral thermal conductivity and a lower axial thermal conductivity.

3. The apparatus of claim 1 , wherein each of the anisotropic thermal layers comprises at least one of: carbon nanotubes and graphene.

4. The apparatus of claim 1 , wherein:
the anisotropic thermal layers divide the regenerator into multiple segments; and
each of the anisotropic thermal layers are configured to reduce heat transfer between adjacent segments of the regenerator.

5. The apparatus of claim 1 , wherein the one or more support layers are configured to impart a higher heat capacity to the at least one anisotropic thermal layer.

6. The apparatus of claim 1 , wherein each of the one or more support layers comprises a screen or mesh.

7. A system comprising:
a cryocooler having a warm end and a cold end, the cryocooler comprising:
a compressor configured to move a fluid between the warm end and the cold end of the cryocooler; and
a regenerator configured to contact the fluid, the regenerator also configured to transfer heat to the fluid and to absorb heat from the fluid as the fluid flows between the warm end and the cold end of the cryocooler;

wherein the regenerator comprises:
multiple anisotropic thermal layers, each of the anisotropic thermal layers comprising a film configured to reduce a flow of heat axially along the regenerator and to spread the absorbed heat radially or laterally in a plane of that anisotropic thermal layer, each of the anisotropic thermal layers comprising at least one allotropic form of carbon, and
one or more support layers configured to structurally support at least one of the anisotropic thermal layers.

8. The system of claim 7 , wherein each of the anisotropic thermal layers has a higher radial or lateral thermal conductivity and a lower axial thermal conductivity.

9. The system of claim 7 , wherein each of the anisotropic thermal layers comprises at least one of: carbon nanotubes and graphene.

10. The system of claim 7 , wherein:
the anisotropic thermal layers divide the regenerator into multiple segments; and
each of the anisotropic thermal layers are configured to reduce heat transfer between adjacent segments of the regenerator.

11. The system of claim 7 , wherein the one or more support layers are configured to impart a higher heat capacity to the at least one anisotropic thermal layer.

12. The system of claim 7 , wherein each of the one or more support layers comprises a screen or mesh.

13. The system of claim 7 , wherein the regenerator is positioned around a pulse tube of the cryocooler.

14. The system of claim 7 , wherein the regenerator is positioned within one stage of a multi-stage cryocooler.

15. A method comprising:
creating a flow of fluid back and forth between a warm end and a cold end of a cryocooler;
transferring heat to the fluid and absorbing heat from the fluid using a regenerator as the fluid flows between the warm end and the cold end of the cryocooler;
reducing a flow of heat axially along the regenerator using multiple anisotropic thermal layers within the regenerator, each of the anisotropic thermal layers comprising a film spreading the absorbed heat radially or laterally in a plane of that anisotropic thermal layer, each of the anisotropic thermal layers comprising at least one allotropic form of carbon; and
structurally supporting at least one of the anisotropic thermal layers using one or more support layers.

16. The method of claim 15 , wherein each of the anisotropic thermal layers has a higher radial or lateral thermal conductivity and a lower axial thermal conductivity.

17. The method of claim 15 , wherein each of the anisotropic thermal layers comprises at least one of: carbon nanotubes and graphene.

18. The method of claim 15 , wherein each of the anisotropic thermal layers has a controllable porosity to reduce occurrence of a pressure drop across the regenerator.

19. The method of claim 15 , wherein:
the anisotropic thermal layers divide the regenerator into multiple segments; and
each of the anisotropic thermal layers are configured to reduce heat transfer between adjacent segments of the regenerator.

20. The method of claim 15 , further comprising:
using the one or more support layers to impart a higher heat capacity to the at least one anisotropic thermal layer.

Assignees

• Raytheon Co

Inventors

• Conrad Theodore J
• Ellis Michael J
• Bellis Lowell A
• Chow James R
• Schaefer Brian R
• Matsuoka Troy T

Classifications

• F25B2309/1415

  Pulse-tube cycles characterised by regenerator details · CPC title

• F25B9/145

  pulse-tube cycle · CPC title

• F25B2309/003

  characterised by construction or composition of the regenerator · CPC title

• F25B9/10 Primary

  with several cooling stages · CPC title

• F25B9/14 Primary

  characterised by the cycle used, e.g. Stirling cycle · CPC title