EP0574678A1 - Wärmerohr - Google Patents

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Publication number
EP0574678A1
EP0574678A1 EP93106689A EP93106689A EP0574678A1 EP 0574678 A1 EP0574678 A1 EP 0574678A1 EP 93106689 A EP93106689 A EP 93106689A EP 93106689 A EP93106689 A EP 93106689A EP 0574678 A1 EP0574678 A1 EP 0574678A1
Authority
EP
European Patent Office
Prior art keywords
channel
heat
steam
liquid
bulges
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP93106689A
Other languages
German (de)
English (en)
French (fr)
Inventor
Bernhard Prof. Leidinger
Rüdiger Meyer
Klaus Peter Nickel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Erno Raumfahrttechnik GmbH
Original Assignee
Erno Raumfahrttechnik GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Erno Raumfahrttechnik GmbH filed Critical Erno Raumfahrttechnik GmbH
Publication of EP0574678A1 publication Critical patent/EP0574678A1/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
    • F28D15/046—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure characterised by the material or the construction of the capillary structure

Definitions

  • the invention relates to an arrangement for the transfer of heat, consisting of a heat pipe filled with a heat transfer medium, in which at least one flow channel is provided for the liquid and for the heat transfer medium converted to the vaporous state, and in which at least one over the steam flow channel Suction opening with the liquid channel connected nozzle-shaped cross-sectional reduction is arranged.
  • Heat pipes or "heat pipes” for the transport of heat are already known, in particular from the field of space technology.
  • there is usually a liquid on the heat-emitting side Ammonia, evaporates and the steam is directed to the heat-emitting side.
  • the steam condenses, the latent heat stored in it being dissipated to the environment, and the condensate produced flows back again to the heat-absorbing side, the end of the evaporator.
  • the steam flow that occurs is a normal pressure flow, while the liquid flow is a capillary flow.
  • Modern high-performance heat pipes are able to transport amounts of heat of the order of about 1 kW over distances between one and about 20 meters, even with comparatively small temperature differences.
  • This higher performance of the high-performance heat pipes compared to conventional heat pipes is achieved by using channels of different dimensions for the transport of the liquid: While a large number of very small channels with capillary geometries are used in the evaporation area to achieve large driving capillary forces, the flow is guided in the Condenser area and in the transport zone via only a few flow channels, possibly a single channel with a relatively large diameter, which is also referred to as an artery. In this way, the frictional pressure loss is minimized and with the same capillary forces there is a substantially larger fluid mass flow and as a result also a much higher heat flow.
  • a major problem with the operation of such high-performance heat pipes is that their function can be considerably impaired or completely interrupted if there are bubbles in the artery from the vapor of the heat transfer fluid or from gaseous, non-condensable foreign substances. These may either have happened to be there when the heat pipe was put into operation, but they may also have been caused by an operational overload of the heat pipe, for example overheating at the end of the evaporator and the evaporation zone drying out briefly. The bubbles can interrupt the transport of the heat transfer fluid to the heat-absorbing zone, so that it dries out further and the function of the heat pipe is blocked.
  • a disadvantage of an arrangement of ventilation holes in the arterial wall is the fact that the pressure in the steam channel during the operation of the heat pipe is significantly higher than in the artery, so that an operation interruption is required to transfer gas bubbles from the artery into the steam channel.
  • the ventilation holes are blocked by liquid bridges, which must first evaporate before the gas bubbles can pass through, these breaks in operation require a comparatively long period of time before the heat pipe is ready for use again.
  • the arrangement of a Venturi nozzle in the steam channel has the following disadvantage: if there is no gas bubble in the suction area of the nozzle, a, albeit small, amount of heat transfer fluid constantly collects from the artery in the suction pipe. If a gas bubble now reaches the suction opening, the amount of liquid must first be removed from the suction pipe so that it can be sucked out of the artery. Because of the associated large pressure loss of the flow in the intake pipe, the pressure reduction caused in the Venturi nozzle must be considerable, i.e. the nozzle must have a comparatively large cross-sectional constriction. On the other hand, however, this leads to a considerable impairment of the steam flow due to the pressure loss and thus to a greatly reduced performance of the heat pipe.
  • the object of the invention is to design a heat pipe of the type mentioned in such a way that vapor bubbles of the heat transfer fluid and bubbles from non-condensable gas are reliably removed from the flow channel for the fluid during operation of the heat pipe, without this requiring an interruption in operation and without the performance of the heat pipe is significantly impaired.
  • the heat pipe according to the invention combines the approaches known from the cited literature for the removal of blockages by gas or steam bubbles, namely the arrangement of ventilation holes on the one hand and the use of Venturi nozzles on the other without being associated with their disadvantages.
  • the figure shows a longitudinal section through a heat pipe, namely part of the transport zone between the evaporator and the condenser area.
  • the heat pipe is divided in its longitudinal direction by a profile area 1 into two channels 2 and 3, of which the upper channel 2 in the drawing, the steam channel, has the larger cross section.
  • the lower channel 3 forms the liquid channel for the heat transfer fluid flowing back from the condenser area to the evaporator area.
  • the profiled sheet 1 is provided at regular intervals, which in the exemplary embodiment described here can each be approximately one meter, with bulges 4, 5, which extend into the steam channel 2 and which in each case bring about a reduction in the cross section .
  • bulges 4, 5 through holes 6, 7 are made in the profiled sheet 1, which connect the liquid channel 3 to the steam channel 2 and which in the case of the exemplary embodiment described here have a diameter of approximately 0.2 mm.
  • the profiled sheet 1 between two bulges 4, 5 does not run parallel to the longitudinal axis of the tube, but rather increases slightly from the center between the two bulges 4, 5, so that the flow cross-section of the liquid channel 3 increases continuously in the direction of both bulges 4, 5.
  • the expansion of the bulges 4, 5 and the diameter of the through holes 6, 7 are coordinated so that the pressure drop caused by the bulges 4, 5 in the steam channel 2 is so small that for the period in which there is no gas or Steam bubble is in front of the through hole 6, 7, the liquid that collects due to the capillary action of the holes is not sucked into the steam flow but is held in place by the capillary forces.
  • the narrowest point of the liquid channel is not in the middle between two Placing bulges, but for example in each case directly adjacent to the upstream bulge, so that the flow cross section of the liquid channel increases practically in the entire area between two bulges in the direction of flow.
  • This has the advantage in particular in the start-up phase of the heat pipe that the liquid flow and the capillary forces act in the same direction on existing gas or vapor bubbles.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Jet Pumps And Other Pumps (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Treatment Of Fiber Materials (AREA)
EP93106689A 1992-06-17 1993-04-24 Wärmerohr Withdrawn EP0574678A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4219781 1992-06-17
DE4219781A DE4219781C1 (enrdf_load_stackoverflow) 1992-06-17 1992-06-17

Publications (1)

Publication Number Publication Date
EP0574678A1 true EP0574678A1 (de) 1993-12-22

Family

ID=6461183

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93106689A Withdrawn EP0574678A1 (de) 1992-06-17 1993-04-24 Wärmerohr

Country Status (3)

Country Link
US (1) US5314011A (enrdf_load_stackoverflow)
EP (1) EP0574678A1 (enrdf_load_stackoverflow)
DE (1) DE4219781C1 (enrdf_load_stackoverflow)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7884174B2 (en) * 2003-05-05 2011-02-08 Designer Molecules, Inc. Imide-linked maleimide and polymaleimide compounds
US7530231B2 (en) * 2005-04-01 2009-05-12 Pratt & Whitney Canada Corp. Fuel conveying member with heat pipe
US7420810B2 (en) * 2006-09-12 2008-09-02 Graftech International Holdings, Inc. Base heat spreader with fins

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2380520A1 (fr) * 1977-02-09 1978-09-08 Dornier System Gmbh Dispositif assurant le degazage d'un liquide parcourant des tubes de transmission de chaleur
EP0217777A1 (fr) * 1985-09-05 1987-04-08 Societe Anonyme Belge De Constructions Aeronautiques S.A.B.C.A. Caloduc capillaire

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844342A (en) * 1973-11-01 1974-10-29 Trw Inc Heat-pipe arterial priming device
US4058159A (en) * 1975-11-10 1977-11-15 Hughes Aircraft Company Heat pipe with capillary groove and floating artery
US4854379A (en) * 1987-09-25 1989-08-08 Thermacore, Inc. Vapor resistant arteries

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2380520A1 (fr) * 1977-02-09 1978-09-08 Dornier System Gmbh Dispositif assurant le degazage d'un liquide parcourant des tubes de transmission de chaleur
EP0217777A1 (fr) * 1985-09-05 1987-04-08 Societe Anonyme Belge De Constructions Aeronautiques S.A.B.C.A. Caloduc capillaire

Also Published As

Publication number Publication date
DE4219781C1 (enrdf_load_stackoverflow) 1993-09-16
US5314011A (en) 1994-05-24

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