US3521705A - Heat exchange structure and electron tube including such heat exchange structure - Google Patents

Heat exchange structure and electron tube including such heat exchange structure Download PDF

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Publication number
US3521705A
US3521705A US736499A US3521705DA US3521705A US 3521705 A US3521705 A US 3521705A US 736499 A US736499 A US 736499A US 3521705D A US3521705D A US 3521705DA US 3521705 A US3521705 A US 3521705A
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United States
Prior art keywords
heat exchange
channels
heat
exchange structure
wall
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Expired - Lifetime
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US736499A
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English (en)
Inventor
Charles Alphonse Beurtheret
Eugene Jean Douguet
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Compagnie Francaise Thomson Houston SA
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Compagnie Francaise Thomson Houston SA
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/18—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
    • 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
    • F28D5/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, using the cooling effect of natural or forced evaporation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
    • H01J19/28—Non-electron-emitting electrodes; Screens
    • H01J19/32—Anodes
    • H01J19/36—Cooling of anodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
    • H01J2893/0012—Constructional arrangements
    • H01J2893/0027—Mitigation of temperature effects

Definitions

  • a heat exchanging separating wall, one surface of which is heated, has the other surface formed with projections (2) separated from each other by channels (3), the dimensions of the channels and the projections being defined by the following relationship: depth (b) of the channels from the heat exchange surface is in the order of one quarter of the thermal conductivity (c) of the material forming the structure, and the smallest dimension (a) between channelsthat is the width of the projectionsis greater than the depth (b) of the channels; all lengths being measured in centimeters and the thermal conductivity being measured in watts/centimeter-degree C.
  • (b) should be between 0/4 and c/8, and the width (d) of the channels (3) less than b/ 2; for 0 less than .5 W./cm. C., b should be between 0/4 and 0/2, and d between d/ 2 and b; eflicient transfer of heat by boiling off of liquid, to obtain maximum cooling due to heat vaporization, is thus obtained.
  • the present invention relates to improvementsin heat exchangers, and to high-power electronic tubes in which a good deal of heat must be dissipated, including such heat exchange structures; and more particularly to heat exchangers which utilize the heat evaporation of a liquid from a wall of highly heat-conductive material in order to effect cooling of the wall itself.
  • Heat exchangers in which one surface of a wall of highly heat conductive material is bathed in a liquid, which evaporates on contact, are known. Such heat exchangers can operate with fluids subject to natural thermal convection, or with forced circulation, and maintained at either atmospheric, or elevated pressures. Liquid vaporized from such a heat exchanger is then condensed in a condenser, or against cooler surfaces.
  • one surface, or face of a heat exchange wall is immersed in, or bathed by a liquid which will be evaporated upon contact with the heat exchange wall; the wall itself is formed with projections separated from each other by channels of dimensions which are critical. Measured in centimeters, the depth of the channels should be of a value in the order of one quarter of the thermal conductivity of the heat exchange wall, measured in watts per centimeter-degree centigrade; the smallest dimension of the projections, measured parallel to the wall (or tangentially, if it is curved) should be greater than the depth of the channels. Ranges of dimensions useful in the present invention will be pointed out in connection with the detailed description below.
  • FIG. 1 illustrates, in perspective, an anode structure for a power tube (with the tube elements omitted for purposes of clarity) incorporating the present invention
  • FIG. 2 is a perspective view of a plane heat exchange structure having transverse channels
  • FIGS. 3, 4 and 5 are enlarged vertical cross-sectional views through heat exchange walls and illustrate various embodiments of the structures, and the channels therein.
  • the heat exchange anode structure, in form of a tube, of FIG. 1 is heated internally by electronic components within the tube, not shown and not forming part of the present invention.
  • the external surface of the anode structure 1 is bathed, or submerged in a cooling liquid maintained within an enclosure, likewise not shown and well known in the art.
  • Forced circulation of the liquid along the wall of the anode 1 constantly supplies new heat exchange liquid at a pressure and temperature such that the heat exchange liquid will boil off upon contact with the heat exchange wall; the resulting vapor is immediately condensed within the remaining pool of the liquid itself, or by contact with an external condenser.
  • the forced circulation of the liquid along the wall is schematically indicated b arrows A-A.
  • Narrow channels 3, and located as generatrices of the cylinder forming the anode structure of the tube define a series of protuberances or projections 2, arranged parallel to each other similar to the channels 3.
  • the material of the anode itself is a good conductor of heat, such as copper.
  • the temperature thereof is stabilized by the presence of colder end portions subject to stable nucleated boiling.
  • the presence of these relatively cold end regions stabilizes the temperature of intermediate portions by internal conduction of heat within the metal of the heat exchange wall. Additionally, the presence of intense boiling at the edge portions tends to break up vapor films which may form at the hotter parts of the structure so that the entire surface will be capable to transmit heat flux very close to the critical flux.
  • the heat exchange wall structures are different from those known structures which merely have random grooves to increase surface area, but of little significance to cause the currents of the cooling liquid therealong to behave in a certain way, and to support vaporization without permitting hot spots. Turbulence of heat exchange liquid is, of course obtained with any break-up of a smooth heat exchange surface, and increases the heat exchange capability. Shallow grooves do not cause a sufiicient temperature gradient at the edges in order to stabilize the boiling of heat exchange material along the edge walls after the critical temperature has been exceeded, as is the case in accordance With the present invention.
  • FIG. 2 A plane heat exchange structure is illustrated in FIG. 2.
  • Channels 4 and 5 define rectangular projections 2, and separated by different amounts from each other, so that the protuberances will have a smaller dimension a and a larger dimension a
  • the depth b of the channels measured in centimeters, is in the order of one quarter of the thermal conductivity of the material of the heat exchange structure, measured in watts per centimeter-degree C.
  • the smaller dimension a of the projections or protuberances 2 must be greater than the depth b of the channels; for example a may be between 2b and 8b. In FIG. 1, where only a single dimension is appropriate to the protuberances, this dimension is indicated by a.
  • the material of the wall has a thermal conductivity 0 which is greater than w./ cm. C., then the optimum value of b is between 0/ 8 and c/4.
  • the width of the channels, indicated by d in FIG. 2, experimentally, has been determined to be preferably less than b/Z.
  • optimum depth of the channels, b is between 0/4 and 0/2; and the width of the grooves, d, is then preferably between b and b/2.
  • FIG. 3 illustrates a heat exchange structure in which the projections, or protuberances have a trapezoidal cross section, in that the top edges are rounded off as at 7, in order to better prevent break-up of the boiling at the end zones.
  • the width d of the grooves is then measured at the point in which a vertical line (with respect to the cross sectional diagram of FIG. 3) divides the area above and below the intersection of the verticals into two equal zones.
  • the width of the protuberance a is measured with respect to a similar reference line
  • the channels, or grooves 3 may be broken up by a central rib, as illustrated in FIGS. 4 and 5.
  • Rib 9 separates the channels into two subdivisions 8 (FIG. 4) and 8 (FIG. 5).
  • the arrangement of FIGS. 4 and 5 has the advantage that the heat to be dissipated which is produced by the aniso-thermal, active heat exchange regions can be substantially increased, thus permitting increase of heat dissipated from the projections 2.
  • FIG. 4 illustrates a structure in which the sub-divisions 8 of the channels are perpendicular to the surface of the heat exchange structure; whereas FIG. 5 illustrates an arrangement in which diverging channels 8', which can be rounded at the bottom, define a separating rib 9', with the projections 2 therebetween.
  • the heat exchange surfaces in accordance with the present invention may be readily manufactured and machined and thus result in a structure which is less expensive to make.
  • the heat exchange structures in accordance with the present invention are particularly useful to operate with forced-circulation heat exchange fluid under pressure and are particularly applicable to the cooling of high power electron tubes, nuclear reactor rods or elements of thermal machines.
  • the present invention has been described in connection with a heat exchange structure forming an anode for an electron tube, and in connection with flat heat exchange surfaces. Various changes and modifications may be made, within the inventive concept, as determined by the requirements of specific uses.
  • Heat exchange structure comprising a metallic wall section subject to heating at one surface thereof, said wall section being immersed in a heat exchange medium at the other surface thereof and exchanging heat with said medium, said other heat exchange surface being formed with projections (2) separated from each other by channels (3),
  • the improvement comprises that the dimensions of said channels and projections are defined by the relationship: the depth (b) of the channels is equal c/n where (c) is the thermal conductivity of the wall section and n has a value comprised between 2 and 8, while the smallest dimension (a, a between channels, of said projections, is greater than the depth (b) of the channels, and the average width (d) of the channels is on the order of or less than b.
  • Heat exchange structure according to claim 1 wherein, for a material having a thermal conductivity greater than 1 w./cm.- C., the depth (b) of the channel is between 0/4 and c/ 8, and the average width (d) of said channels (3) is less than half the depth.
  • Heat exchange structure according to claim 1 wherein, for a material having a thermal conductivity which is less than 0.5 w./cm.- C., the depth (b) of the channel is between 0/4 and 0/2, and the average width (d) of the channels (3) is in the range of between b/Z and b.
  • Heat exchange structure according to claim 1, wherein the material has a thermal conductivity (0) of 1 c 0.5; and the depth (b) of the channels is in the order of 0/4 and the average width (d) of the channels is in the order of b/ 2.
  • Heat exchange structure according to claim 1 angle with respect to a plane perpendicular to the heat wherein the outer edges of the channels (3) are rounded exchange surface.
  • Heat exchange structure according to claim 1 References Clled wherein said heat exchange medium is a fluid subject to 5 UNITED STATES PATENTS forced circulation (A). 7. Heat exchange structure according to claim 1, 523 5:: wherein said channels are formed in pairs, and subdivided e e (FIGS. 4, 5:8) with ridges (9) therebetween.
  • Heat exchange structure according to claim 7, 10 ROBERT OLEARY: Pmnary Exammer wherein said subdivisions are arranged to have their AV 111-, Asslstant Examiner median planes divergent and inclined with respect to the surface of said heat exchange structure.
  • Heat exchange structure according to claim 1, 165 133, 183, 185; 31321, 22, 35, 36 wherein the walls of said channels are inclined at an 15

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
US736499A 1967-06-13 1968-06-12 Heat exchange structure and electron tube including such heat exchange structure Expired - Lifetime US3521705A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR110185 1967-06-13

Publications (1)

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US3521705A true US3521705A (en) 1970-07-28

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US736499A Expired - Lifetime US3521705A (en) 1967-06-13 1968-06-12 Heat exchange structure and electron tube including such heat exchange structure

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US (1) US3521705A (enrdf_load_stackoverflow)
CH (1) CH485996A (enrdf_load_stackoverflow)
FR (1) FR1550992A (enrdf_load_stackoverflow)
GB (1) GB1207216A (enrdf_load_stackoverflow)
NL (1) NL6808118A (enrdf_load_stackoverflow)
OA (1) OA02827A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4879891A (en) * 1987-04-27 1989-11-14 Thermalloy Incorporated Method of manufacturing heat sink apparatus
US4884331A (en) * 1987-04-27 1989-12-05 Thermalloy Incorporated Method of manufacturing heat sink apparatus
US6371199B1 (en) * 1988-02-24 2002-04-16 The Trustees Of The University Of Pennsylvania Nucleate boiling surfaces for cooling and gas generation
US20090294112A1 (en) * 2008-06-03 2009-12-03 Nordyne, Inc. Internally finned tube having enhanced nucleation centers, heat exchangers, and methods of manufacture
US20120285664A1 (en) * 2011-05-13 2012-11-15 Rochester Institute Of Technology Devices with an enhanced boiling surface with features directing bubble and liquid flow and methods thereof
US20160025010A1 (en) * 2013-03-26 2016-01-28 United Technologies Corporation Turbine engine and turbine engine component with cooling pedestals

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4159739A (en) * 1977-07-13 1979-07-03 Carrier Corporation Heat transfer surface and method of manufacture
JPS59112199A (ja) * 1982-12-17 1984-06-28 Hitachi Ltd 熱交換壁及びその製造方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3235004A (en) * 1962-02-23 1966-02-15 Thomson Houston Comp Francaise Heat dissipating structure
US3367415A (en) * 1964-12-17 1968-02-06 Thomson Houston Comp Francaise Anisotherm evaporation heattransfer structure

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3235004A (en) * 1962-02-23 1966-02-15 Thomson Houston Comp Francaise Heat dissipating structure
US3367415A (en) * 1964-12-17 1968-02-06 Thomson Houston Comp Francaise Anisotherm evaporation heattransfer structure

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4879891A (en) * 1987-04-27 1989-11-14 Thermalloy Incorporated Method of manufacturing heat sink apparatus
US4884331A (en) * 1987-04-27 1989-12-05 Thermalloy Incorporated Method of manufacturing heat sink apparatus
US6371199B1 (en) * 1988-02-24 2002-04-16 The Trustees Of The University Of Pennsylvania Nucleate boiling surfaces for cooling and gas generation
US20090294112A1 (en) * 2008-06-03 2009-12-03 Nordyne, Inc. Internally finned tube having enhanced nucleation centers, heat exchangers, and methods of manufacture
US20120285664A1 (en) * 2011-05-13 2012-11-15 Rochester Institute Of Technology Devices with an enhanced boiling surface with features directing bubble and liquid flow and methods thereof
US10697629B2 (en) * 2011-05-13 2020-06-30 Rochester Institute Of Technology Devices with an enhanced boiling surface with features directing bubble and liquid flow and methods thereof
US11598518B2 (en) 2011-05-13 2023-03-07 Rochester Institute Of Technology Devices with an enhanced boiling surface with features directing bubble and liquid flow and methods thereof
US20160025010A1 (en) * 2013-03-26 2016-01-28 United Technologies Corporation Turbine engine and turbine engine component with cooling pedestals

Also Published As

Publication number Publication date
OA02827A (fr) 1970-12-15
FR1550992A (enrdf_load_stackoverflow) 1968-12-27
NL6808118A (enrdf_load_stackoverflow) 1968-12-16
GB1207216A (en) 1970-09-30
CH485996A (fr) 1970-02-15

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