Low pressure drop condenser/evaporator pump heat exchanger

• US 4,869,313 A
• Filed: 07/15/1988
• Issued: 09/26/1989
• Est. Priority Date: 07/15/1988
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: General Electric Company
• Inventors: Fredley, Joseph E.
• Primary Examiner(s): DAVIS JR, ALBERT
• Application Number:
  US07/219,119
• Time in Patent Office: 438 Days
• Field of Search: 165/41, 165/110, 165/156, 165/104.14, 165/104.26
• US Class Current: 165/41
• CPC Class Codes: B64G 1/50 for temperature control
• CPC Class Codes: B64G 1/503 Radiator panels
• CPC Class Codes: B64G 1/506 Heat pipes
• CPC Class Codes: F28D 15/043 forming loops, e.g. capillary pumped loops
• CPC Class Codes: F28F 13/187 especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites
• CPC Class Codes: F28F 2200/005 Testing heat pipes

Abstract

A heat exchanger includes a porous cylindrical sleeve with a bore into which liquid coolant is admitted. The liquid permeates the sleeve but cannot leave the outer surface. A pipe surrounds the sleeve. The pipe has a cylindrical outer surface and an inner surface defining protrusions and vapor channels about the protrusions. The inner ends of the protrusions bear against the outer surface of the sleeve. A plurality of helical channels are helically arranged about and in thermal contact with the outer surface of the pipe. The ends of the helical channels are coupled to plenums. Each plenum is coupled by a pipe and a fluid disconnect to one end of a thermal loop including a heat source. Heat-laden vapor passes through the helical channels and is cooled to liquid. The heat is withdrawn into the pipe and passes through the protuberances to vaporize the liquid near the surface of the porous sleeve. The resulting vapor is collected and coupled to a condenser.

Claims

1. A heat transfer arrangement, comprising:

an elongated porous pipe including an elongated bore and a cylindrical outer surface centered on an axis, said bore being closed off near a first end of said pipe and open at a second end of said pipe;

a thermally conductive housing surrounding said porous pipe, said housing including an inner surface defining inwardly-directed protruding portions and first channels for the flow of fluid about said protrusions, said housing also including a cylindrical outer surface, said housing being dimensioned so that the innermost ends of said protrusions bear against said outer surface of said porous pipe;

a plurality of second channels helically disposed about and in thermal contact with said outer surface of said housing, each of said second channels being dimensioned so that the surface tension forces acting on a heat transfer liquid therein are of the same order of magnitude as the gravitational forces when said heat transfer arrangement is in a one-G environment;

a first plenum coupled to said first end of said second channels and adapted for coupling heat transfer vapor thereto for transferring heat to said housing and thereby condensing said heat transfer vapor into said heat transfer liquid;

a second plenum coupled to said second end of said second channels and adapted for collecting said heat transfer liquid for return to a source of heat;

coupling means adapted for coupling a source of working liquid to said bore at said second end of said pipe, whereby said liquid perfuses said porous pipe and said heat transferred to said housing is coupled by said protrusions to vaporize said working liquid, to produce working vapor which flows into said first channels; and

a third plenum coupled to said first channels for collecting said working vapor for return to a condenser.

2. The combination of claim 1 wherein said plurality of passages are of a sufficiently small diameter that helical circulation along the walls is primarily due to surface tension and secondary flow effects.

3. The combination of claim 2 wherein the diameter of said passages is on the order of 1/10th of an inch.

4. A heat exchanger adapted for testing in a 1 G gravity environment and operation in a microgravity environment, comprising:

an elongated thermally conductive pipe including an elongated cylindrical outer surface and an inner surface defining inwardly directed projections and vapor channels extending about said projections;

an elongated porous sleeve located within said pipe, said porous sleeve including an outer surface in thermal contact with ends of said projections;

coupling means associated with said porous sleeve and adapted to be coupled to a source of working fluid in liquid form for causing said working fluid in liquid form to perfuse the pores of said porous sleeve;

a plenum coupled to said vapor channels for collecting working fluid in vapor form;

an elongated heat pipe including a portion adapted to be coupled to a heat-rejecting device for rejecting heat, and also including an elongated cylindrical portion adapted for receiving heat which is to be rejected;

a source of a flow of second fluid which when heat-laden is to be cooled;

a plurality of channels helically disposed about and thermally coupled to said elongated cylindrical portion of said heat pipe, said plurality of channels being adapted for receiving said second fluid, said channels being wetted by said liquid form of said second fluid and having cross-sectional dimensions selected so that the surface tension forces of said liquid form of said second fluid are predominant relative to the gravitational forces on said second fluid in a reference gravity environment, and the helix dimensions being selected so that centrifugal forces resulting from the flow of said liquid form of said second fluid through said helical channels are at least significant relative to said gravitational forces in said reference gravity environment, whereby heat is transferred from said second fluid in said channels to said pipe and from said pipe to said working liquid which evaporates from said porous sleeve and enters said vapor channels in much the same manner in a microgravity environment as in a gravity environment, and testing can therefore take place in a gravity environment, and operation can take place in a microgravity environment.

5. A heat exchanger according to claim 4 wherein said coupling means comprises an elongated bore through at least a portion of said sleeve, said bore being adapted to be coupled to a source of said working fluid in liquid form.

6. A heat exchanger according to claim 4 wherein said bore is closed off at one end of said porous sleeve.

7. A heat exchanger according to claim 4 wherein both said working fluid and said second fluid are ammonia.

8. A heat exchanger according to claim 7 wherein said cross-section dimensions are about 1/10 inch (2.5 mm).

9. An exchanger according to claim 8 wherein the pressure drop across said plurality of channels is less than about 0.04 PSI (280 N/m²).

10. An exchanger according to claim 8 wherein said helically disposed channels have an average diameter of approximately 0.8 inch for a linear flow rate within each of said channels of about 0.25 lbm/hour.

11. A heat exchanger for a first spacecraft module including a heat rejection arrangement, adapted for rejecting heat received from a first pipe in the form of heat-laden first vapor for condensing said vapor to a first liquid which is returned by way of a second pipe, which first spacecraft module is adapted to be mated to a second spacecraft module which includes a capillary pumped loop for absorbing heat from a source and for transferring the heat to a working liquid received over a third pipe to generate heat-laden of said working liquid vapor in a fourth pipe, said heat exchanger comprising:

a porous sleeve defining a cylindrical outer surface and also defining a central bore closed at a first end and open at a second end, said second end being adapted for receiving liquid working fluid from said radiator by way of said third pipe, whereby said liquid working fluid permeates said sleeve;

a thermally conductive elongated fifth pipe including a cylindrical outer surface centered on an axis and an inner surface defining protuberances projecting toward said axis and also defining vapor channels about said protuberances, said protuberances bearing against said outer surface of said sleeve, said vapor channels being closed in a region near said second end of said sleeve and open near said first end of said sleeve; and

a plurality of passages helically arranged about, and in thermal contact with, said outer surface of said fifth pipe, said passages being connected to a common first junction near said first end of said sleeve, and connected to a common second junction near said second end of said sleeve, said first junction being adapted to be coupled to said first pipe for receiving said heat-laden first vapor therefrom for coupling said first vapor into said plurality of passages for condensing said first vapor into said first liquid by transferring heat to said fifth pipe, said second junction being adapted for collecting said first liquid and for coupling said first liquid to said second pipe, whereby said heat transferred to said fifth pipe causes said liquid permeating said porous sleeve to change to vapor and to flow in said vapor channels to said fourth pipe.