TWO PHASE HEAT TRANSFER SYSTEMS AND EVAPORATORS AND CONDENSERS FOR USE IN HEAT TRANSFER SYSTEMS

• US 20120024497A1
• Filed: 10/04/2011
• Published: 02/02/2012
• Est. Priority Date: 06/30/2000
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Kroliczek, Edward J., Khrustalev, Dmitry, Morgan, Michael J.
• Granted Patent: US 9,200,852 B2
• Time in Patent Office: Days
• US Class Current: 165/104.13
• CPC Class Codes: F28D 15/0266 with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers F28D15/043 takes precedence
• CPC Class Codes: F28D 15/04 with tubes having a capillary structure
• CPC Class Codes: F28D 15/043 forming loops, e.g. capillary pumped loops
• CPC Class Codes: F28D 15/046 characterised by the material or the construction of the capillary structure

Abstract

A heat transfer system includes a first loop and a second loop. The first loop includes a condenser having a vapor inlet and a liquid outlet, a vapor line in fluid communication with the vapor inlet of the condenser, a liquid line in fluid communication with the liquid outlet of the condenser, and primary evaporators fluidly coupled in series with the liquid line and in parallel with the vapor line. The second loop includes a reservoir, a secondary evaporator having a vapor outlet coupled to the vapor line and a fluid inlet coupled to the reservoir, and a sweepage line in fluid communication with the reservoir and the primary evaporators.

Claims

1. A heat transfer system comprising:

at least two evaporators each comprising a fluid inlet and a fluid outlet;

a condenser including a liquid outlet and a vapor inlet, the vapor inlet being fluidly coupled to at least one of the at least two evaporators;

a coupling line providing fluid communication between the fluid outlet of a first evaporator of the at least two evaporators and the fluid inlet of a second evaporator of the at least two evaporators; and

a liquid line providing fluid communication between the liquid outlet of the condenser and the fluid inlet of the first evaporator and being thermally linked with and coupled to the coupling line.

2. The heat transfer system of claim 1, further comprising a secondary system comprising:

a reservoir;

a secondary evaporator fluidly linked to the reservoir and to the vapor line;

a fluid outlet on the secondary evaporator; and

a sweepage line providing fluid communication between the reservoir and the fluid outlet of the second evaporator of the at least two evaporators.

3. The heat transfer system of claim 1, wherein the vapor inlet of the condenser is fluidly coupled to the at least two evaporators.

4. The heat transfer system of claim 1, wherein the liquid line is thermally linked with the coupling line by a bond between a tube of the liquid line and a tube of the coupling line.

5. The heat transfer system of claim 1, wherein the liquid line is thermally linked with the coupling line such that the liquid line is at least partially inside the coupling line.

6. A condenser comprising:

a housing defining a plurality of channels extending along an axial direction;

a vapor inlet fluidly coupled to each of the plurality of channels;

a liquid outlet fluidly coupled to each of the plurality of channels; and

a porous structure positioned between at least two channels of the plurality of channels and the liquid outlet and fluidly coupled to the at least two channels of the plurality of channels to the liquid outlet, the porous structure having a pore size large enough to permit liquid to flow from the at least two channels of the plurality of channels through the porous structure to the liquid outlet.

7. The condenser of claim 6, wherein the at least two channels of the plurality of channels defined by the housing are microchannels.

8. The condenser of claim 6, wherein the porous structure extends in a direction that is perpendicular to the axial direction.

9. The condenser of claim 6, wherein the porous structure extends across all channels of the housing such that the porous structure fluidly couples to all channels.

10. The condenser of claim 6, wherein the porous structure is inside the housing.

11. The condenser of claim 6, wherein the porous structure has a pore size that is small enough to generate a capillary pressure of a same order of magnitude as a pressure drop across the at least two channels of the plurality of channels defined within the housing.

12. An evaporator comprising:

an outer enclosure;

a liquid inlet fluidly coupled through the outer enclosure;

a vapor outlet fluidly coupled through the outer enclosure; and

a wick within the outer enclosure, fluidly coupled to the liquid inlet, extending along an axial direction, the wick having an outer surface positioned adjacent to the outer enclosure, and comprising;

a plurality of circumferential grooves formed in the outer surface of the wick, the plurality of circumferential grooves extending in a direction that is non-parallel to the axial direction; and

a plurality of channels formed in the wick, each channel of the plurality of channels being fluidly connected to the plurality of circumferential grooves, extending along the axial direction of the wick, and being fluidly coupled to the vapor outlet.

13. The evaporator of claim 12, wherein the outer surface of the wick contacts the outer enclosure.

14. The evaporator of claim 12, wherein the outer surface of the wick has a structure that includes a plurality of protruding portions and a plurality of recessed portions, each circumferential groove of the plurality of circumferential grooves being formed in a space defined between a recessed portion of the plurality of recessed portions, at least two protruding portions of the plurality of protruding portions, and the outer enclosure.

15. The evaporator of claim 12, wherein each circumferential groove of the plurality of circumferential grooves extends perpendicularly to the axial direction.

16. The evaporator of claim 12, wherein the plurality of circumferential grooves are fluidly coupled to each other only through at least one channel of the plurality of channels of the wick.

17. The evaporator of claim 12, wherein each circumferential groove of the plurality of circumferential grooves is formed along an outer surface of the wick.

18. The evaporator of claim 12, wherein the plurality of circumferential grooves are formed as a continuous spiral.

19. The evaporator of claim 12, wherein the outer surface of the wick defines the plurality of channels.

20. The evaporator of claim 19, wherein the outer enclosure includes a heat receiving surface.

21. The evaporator of claim 20, wherein the plurality of channels is positioned along an inner circumference of the wick that has a radius less than the radius of an outer circumference of the wick.

22. The evaporator of claim 20, wherein the plurality of channels is on the side of the wick near the heat receiving surface.

23. The evaporator of claim 12, wherein each channel of the plurality of channels extends a length of the wick that is less than a total length of the wick as measured along the axial direction.

24. An evaporator comprising:

an outer enclosure;

a vapor outlet fluidly coupled through the outer enclosure;

a wick within the outer enclosure, the wick fluidly coupled to the vapor outlet;

an end cap bonded to the outer enclosure, contacting the wick, and having a thermal conductivity that is less than a thermal conductivity of the outer enclosure; and

a liquid inlet fluidly coupled through the end cap to the wick.

25. The evaporator of claim 24, further comprising a porous structure within the end cap and positioned between the liquid inlet and the wick.

26. The evaporator of claim 25, wherein the porous structure thermally isolates the wick from the liquid inlet.

27. The evaporator of claim 25, wherein the porous structure has a thermal conductivity that is less than a thermal conductivity of the outer enclosure.

28. The evaporator of claim 25, wherein the porous structure has pores that are sized to permit liquid flow, but block vapor flow.

29. An evaporator comprising:

an outer shell;

a vapor outlet fluidly coupled through the outer shell;

a liquid inlet fluidly coupled through the outer shell;

a wick within the outer shell, the wick fluidly coupled to the vapor outlet; and

a porous structure thermally isolating the wick from the liquid inlet, having a thermal conductivity that is less than a thermal conductivity of the outer shell, and having pores sized to permit liquid flow, but block vapor flow.

30. The evaporator of claim 29, wherein the porous structure includes a liquid distribution groove fluidly coupled to the liquid inlet to receive fluid.

31. The evaporator of claim 30, wherein the outer shell includes an end cap and an outer enclosure, and the end cap is bonded to the outer enclosure, contacts the wick, and has a thermal conductivity that is less than the thermal conductivity of the outer enclosure.

32. The evaporator of claim 31, wherein the liquid inlet is fluidly coupled through the end cap to the wick.

33. The evaporator of claim 31, further comprising a fluid outlet fluidly coupled through the end cap, wherein the porous structure allows liquid to flow inside the end cap along the liquid distribution groove from the liquid inlet to the fluid outlet.