FR2707381A1 - Cooling structure and method for its manufacture - Google Patents

Abstract

a) The invention relates to a cooling structure suitable in particular for hypersonic engine mechanisms, and to a method for its manufacture; b) the cooling structure is characterized in that: - it is made as a multi-layered plate composed of cover layers (1, 11) and a central layer, the central layer comprising a structure of fibers with metal of heat-conducting matrix, layer in which the cooling channels are coated, and the manufacturing process is characterized in that, after assembly, the central layer of the cooling structure is compacted with the central layer evacuated , by hot isostatic pressing.

Description

"Cooling structure and process for its manufacture

"

  The invention relates to a cooling structure

  metal material with cooling channels

  incorporated and a process for its manufacture.

  Known cooling structures

  take, on the far side of the hot spring of a

  King to cool, cooling channels through

  which flows a cooling medium. These channels of

  cooling are either incorporated into the wall or

  diced or brazed in the form of cooling tubes on the wall to be cooled. The material of the wall to be cooled is essentially chosen according to the type of the hot source, while for chemical equipment with heat sources of reaction, it is also necessary to cool the walls of glass or ceramics. These have the advantage to withstand high temperatures and not require large cooling powers. However, it is a handicap that the walls of glass or ceramic are very fragile and break under the effect of mechanical bending loads, as they are sensitive to thermal shocks, and that in addition their power

  Thermal conductivity is extremely low.

  Metal cooling structures

  are known from patent application DE-PA-41 37 636.2-44.

  These have the disadvantage of being constructed so

  very complex and to be carried out to withstand

  erations and mechanical loads, because they are pre-

  feel on the walls of a hot gas turbine, a rocket nozzle or a hypersonic engine, in

  high alloyed, low heat conduction rates,

  at high temperatures, such as

  alloys based on nickel or cobalt,

  as well as thermal loads as well as

  0lo caniques. These materials have not only the disadvantage of a low thermal conductivity, but also of being

  very expensive and difficult to machine.

  High thermal conductivity metals such as silver or gold are usable metals,

  overpriced for a technical application mentioned above.

  Copper, aluminum and their alloys actually have

  high thermal conductivity but have the disadvantage

  deny to contain, at high temperature, resistances

weak mechanics.

  The object of the invention is therefore to indicate a cooling structure and a method for its

  realization, which has a high thermal conductivity

  with improved mechanical strength and which can

  to be manufactured at an interesting cost.

  This problem is solved according to the invention, by the features of claim 1, by means of a cooling structure made as a multi-layer plate composed of covering layers and a central layer, while the central layer has a fibrous structure with a matrix metal conducting heat layer in which are coated the cooling channels. This cooling structure has the advantage

  to implement as a load-bearing core layer and

  cold, a fibrous structure that allows, a

  on the other hand, to use cheap materials as

  tracks or cover plate materials and to obtain in addition a large conductive capacity of the

  heat, and finally realize because of the finite structure

  shreds an extreme mechanical strength. For this structure, we use as metals

  thermal conductors, non-ferrous heavy metals

  bare, preferably bronze, brass, copper, aluminum

  minium or their alloys. The structure has the advantage

  that cheap materials can be used.

  In a preferred embodiment of the invention, the fibrous structure comprises a plurality of fiber layers, the fibers of the fibrous structure being directed in the direction of tensile stresses due to operation. A

  warping or buckling of the cooling structure

  are therefore advantageously prevented. Like the canals

  are located inside the structure.

  fiber and thus weaken the central layer, the

  central layer comprises, with respect to the coating plates

  free continuous fiber layers closed by cooling channels, which allows for absorption

  safe mechanical loads by the fibrous structure.

  In another preferred embodiment of the invention

  A metal frame surrounds the central layer on all sides. In this way, a weldable or solderable wall element is obtained on all the edges which, thanks to the metal frame, advantageously gives towards all sides

  equivalent possibilities of subsequent machining and

  floor. The frame that loops the central layer on the sides of the cooling structure, can be a component integrated in one of the cover plates, or be

  formed by a lateral folding of one of the cover plates

  or be composed of a prefabricated frame element.

  The fibrous structure preferably comprises composite fibers consisting of fiber cores with metal fiber coatings, wherein the

  fiber recoveries are preferably composed of

  of the same type as the cover plates

  vrement. This has the advantage that with simple processing means it is possible to form a composite material in a central layer, while the metallic coatings of the fibers

  brazed together, welded, sintered, compacted or

  together, so that the fibrous structure preferably forms a core layer of a sealed metal matrix material, a good thermal conductor compacted with

  coated fibers and cooling channels. The man

  The matrix material can therefore come exclusively from

  existing fiber covers or have been added

  completely or partially to the fibrous structure re-

  covered. In addition, the fibers or fiber cores are

  preferably deposited with carbon or silicon carbide.

  These fiber materials have proved particularly

  advantageous in raw materials for matrix in

  heavy non-ferrous metals, because they have a good conductivity

  thermal stability and good adhesion properties, while

  that there is no reactive effect of solid matter between

  solid material and matrix material at operating temperatures. The cooling channels encased in the central layer are preferably received by one of the two

  covering layers which is made of

  Harbor. For this, the surface of the support plate may advantageously be structured with grooves of cooling channels and / or recesses for the central layer, which are covered in the final assembly by the second plate

  recovery, in a simple way.

  In another preferred embodiment of the invention, the cooling channels are made as cooling tubes. This has the advantage that

  in the surface of the carrier plate, it is not necessary

  special structure for cooling ducts.

  However, preferably the carrier plate should simply have bores for receiving the ends of the cooling tubes. The cooling tubes can therefore be arranged parallel and tight next to one another

  others on the carrier plate. The ends of the

  cables for conveying and discharging the cooling agent

  are drilled into holes in the plate of

  support, so that the ends of the cooling tubes

  dying come out at an angle with this plate of

  support. Between, above and below the test tubes

  cooling is positioned the fibrous structure that forms the core layer with the cooling tubes embedded in the fibrous structure. The central layer

  can, for the delimitation of the cooling structure

  As a wall element for a stream of hot gases, having a metal frame which is applied with the central layer on the support plate to close it advantageously on the edges, without the fibers or

  fiber cores of the fibrous structure come into con-

  touch on the edges with the hot gas stream, so that the fiber or fiber core is protected against

  oxidation, erosion and corrosion.

  Holes can also be placed in

  one of the cover plates, which advantageously allows

  In the cooling ducts, the connecting pieces are arranged in the supply and discharge ducts of the coolant, the connecting pieces preferably emerging angularly from one of the cover plates. This has the advantage that the wall elements can be joined to a cooled wall at their edges, and that the connections for the refrigerant supply and discharge pipe are not exposed to the hot gas stream. In addition,

  can produce at a reasonable cost an assembly of

  cords in series or in parallel with a wall of

  because all the fittings are arranged

  easily accessible on the far side of the current

hot gases.

  The connections between them are preferably connected by connecting tubes or

  binding, produced in materials which, on the one hand, pre-

  reduced corrosion and reduced solid reactions with the environment or with the material of the refrigerant structure, and on the

  reduced solid reactions with the material of the con-

  carrier truction. For example, special steel connecting pipes with a chromium content in iron of more than 13% have proved their worth for copper alloy cooling connections. These steel tubes

  are connected to the load-bearing construction by an

  titanium bonding for example, so that the cooling structure of a copper alloy is held in position by a core layer reinforced with

carbon.

  As a cooling agent, we inject

  hydrogen for wall elements intended for

  and change of direction of a hot gas stream in motor mechanisms, or the modification and

  adaptation due to cross-section movements

  nozzles; this hydrogen is preferably preheated at the same time for combustion in chilled wall elements for hypersonic drive mechanisms, rocket propellers or hydrogen-powered drive mechanisms, so that the cooling structure

  at the same time fulfills a function of heat exchanger.

  The problem of indicating a process for

  such a cooling structure, is

  read by the following process steps:

  a) producing a support plate made of thermally conductive material

  with holes for receiving parts

  cord for cooling channels or ends of cooling tubes,

  b) covering the support plate with a first layer of

  by providing junction surfaces in the edge region of the carrier plate or holes,

  (c) introduce cooling tubes with

  bends, or a structure of cooling channels, in the bores and recesses, d) filling the interspaces between the cooling tubes or cooling channels, with other layers of fibers, to form a central layer,

  e) assemble the support plate into a cooling structure

  by enclosing the central layer with a

than recovery.

  This method has the advantage of including costly process steps and providing opportunities.

  to achieve in a simple way a cooling structure

  stably shaped, resistant to high temperatures

  relatively nonferrous heavy metals. In-

  the process is articulated in simple manufacturing phases.

  ples that tolerate as well an automatic manufacture

than mass production.

  Prior to assembly, the cover plate may be covered with a fiber layer by sparing the joining surfaces in the edge area, to fill the cooling structure, even towards the

  cover plate, with a ferro-fiber structure

  mate, so that the cooling channels or tubes of

  cooling are completely embedded in the structure

  fibrous structure. This closed fiber layer can also be placed as a fence of the front central structure

  to assemble the cover plate on the

  cooling or cooling tubes.

  If fiber cores are uncoated or fibers are coated only minimally,

  the assembly of the layers into a cooling structure

  It is not possible to form a closed metal matrix

  between the fiber cores or the fibers, then preferably

  before the assembly, the cavities of the fibrous structure are filled with a material of the same type as that

  of the backing plate by backfilling, infiltration,

  This has the advantage that it is possible to use known methods of powder metallurgy to make a closed metal matrix between the fibers or fiber cores during

assembly.

  In a preferred embodiment of the method, the cover plate and the support plate are assembled into a non-compact wall element by including the core layer by welding or soldering. Compaction is then

  obtained by hot isostatic pressing of the element of pa-

king not compacted.

  A preferred embodiment of the method consists in assembling to connect the connecting pieces or the ends of the tubes in a gastight manner, with

  the holes in the support plate, so that advantageously

  In fact, no gaseous exchange can take place, via the passages in the support plate, between the central layer and the surrounding atmosphere. If, during assembly, the core layer is evacuated

  preferably by performing, for example,

  pressure, then the cooling structure can be hot isostatically pressed, directly after

  the central layer and the material of the

  in the central layer being compacted as well.

  If, preferably, the core layer is to be evacuated after assembly, there must be provided between the support and the cover plate pump nozzles which, after evacuation, are closed in a gas-tight manner. In hot isostatic pressing of the cooling structure, with the core layer evacuated, the latter is compacted into a compact layer of metal matrix material and coated fiber cores and cooling channels, and the plates overlapping are connected to the material of the matrix. The manufacturing method and the construction of the cooling structure are explained by way of example in FIGS. 1 to 4, in which: FIG. 1 shows a support plate with bores and a cooling tube, FIG. a support plate with a closed fiber layer and holes for cooling tubes; - Figure 3 shows a support plate with mounted cooling tubes; - Figure 4 shows a support plate and a

  cover plate before assembly.

  FIG. 1 shows a support plate 1 with bores 2 and a cooling tube 3. First of all, the parts of the cooling tube 3 composed of a heat-conducting metal such as an alloy of Cu, which must constitute the channels 90 degrees are bent at their ends 4. In the support plate 1 composed of a heat-conducting metal are bored holes 2 for receiving the ends 4

  cooling tubes The support plate 1 is

  covered before the introduction of the cooling tubes 3, a closed fiber layer, as shown in FIG.

  2, the fibers 6 being oriented according to the tensions of trac-

  tion due to movement. In this example, we use

  carbon fibers that are coated by electroplating a copper alloy. An edge zone 7 and the bores

  2 are free of the coating by the iron fiber layer.

5.

  In this example, the support plate is in

  and the material of the cooling tubes is in

  a copper / nickel alloy with 10% by weight of nickel.

  Other proven materials for the cooling tubes 3, the support plate 1 and a cover plate 11, as well as for a matrix material, are chromium-alloyed copper with 0.5 to 5% by weight of chromium or aluminum bronze based on 4 to 10% by weight of aluminum, the

  the remainder being copper and adducts.

  Aluminum alloys can also be used. Those-

  have, compared with copper alloys, the advantage of a

  low specific weight. For example, the cooling tubes

  3, the support plate 1, a cover plate

  11 and a matrix metal are composed of: - aluminum with 3.8 to 4.9% by weight of copper 1.2 to 1.8% by weight of magnesium 0.3 to 0.9% by weight of manganese and trace elements, or aluminum with 2.2 to 2.7% by weight of lithium 0.5 to 1.2% by weight of magnesium 1.0 to 1.6% by weight of copper and trace elements, or aluminum with 5.1 to 6.1% by weight of zinc 2.1 to 2.9% by weight of magnesium 1.2 to 2% by weight of copper

  and elements in the form of traces.

  or: - aluminum with 0.8 to 1.2% by weight of magnesium 0.4 to 0.8% by weight of silicon 0.15 to 0.4% by weight of copper

  and elements in the form of traces.

  Brass, which consists mainly of copper with 30% by weight of zinc, was also found

  as a material indicated for the cooling tubes

  3, the support plate 1, a cover plate 11

  as well as matrix material.

  Another copper alloy composed of 10 to 20% by weight of zinc, 1 to 5% by weight of titanium and the remainder essentially of copper, has been successfully used as

  non-ferrous heavy metal for the multi-layer structure

  ches. FIG. 3 shows the support plate 1 with mounted cooling tubes 3, which are inserted by

  their tubular ends 4 in the bores 2 by

  dicing or brewing, so that the tubular ends 4

  protrude from support plate 1 forming a bend.

  On the edge zone 7 is preferably placed a metal frame

  10 and the interspaces between the cooling tubes 3 between each other and between the cooling tubes 3 and the frame 10 are filled by other means. fiber layers 17 indicated in

Figure 4.

  Figure 4 shows a support plate 1 and a cover plate 11 before assembly. For this, the cover plate 11 is covered with at least one

  closed fiber layer 12, 13, the edge zone 14 remains

  rant spared. The cover plate 11 is, in

  the environment under vacuum and in the warmed state,

  on the frame in direction A and attached to frame 10 and

  the support plate 1. In place of the frame 10, in a

  Advantageously according to the invention, the edges of the cover plate 11 can be bent downwards in the edge area and be fixed to the edge region 7 of the support plate 1. The tube ends 4 are welded or brazed with the holes 2 in the support plate 1, in a gas-tight manner. The bonded part is heated under vacuum, degassed and then welded. Then, this structure with several

  noncompact layers is compacted in an isostatic press

  warm, the fiber envelopes made of a conductive metal

  the central layer into a metal matrix, which makes it possible to obtain an element

  compacted wall with a compacted core layer.

Claims (18)

R E V E N D I C AT I S S   1) Cooling structure of metal material with incorporated cooling channels, characterized in that it is made as a multi-layer plate composed of covering layers (1, 11) and a central layer, the central layer comprising a fiber structure with heat-conducting matrix metal, a layer in which the channels are embedded cooling.   2) Cooling structure according to the   claim 1, characterized in that the   fiber layers, and the fibers in the fiber structure are directed in the directions of the fibers.   tensile voltages due to operation.   3) Cooling structure according to the   1 or 2, characterized in that the central layer   trale comprises, with respect to the cover plates (1, 11), layers of free continuous fibers, closed by cooling channels.   4) Cooling structure according to one   Claims 1 to 3, characterized in that a frame   metal surrounds the central layer on all sides.    ) Cooling structure according to one   claims 1 to 4, characterized in that the structure   fibrous fiber comprises composite fibers consisting of   fiber cores with metallic overlays of the   from metal materials of the same type as cover plates.   6) Cooling structure according to one   Claims 1 to 5, characterized in that the layer   central is made of metal matrix material, good thermal conductor, compacted with fibers and coated cooling channels.   7) Cooling structure according to one   claims 1 to 6, characterized in that the structure   fibrous fiber includes fibers or fiber cores   carbon compounds or silicon carbide.   ) 'Cooling structure according to one   claims 1 to 7, characterized in that the   (1, 11) are composed of non-ferrous heavy metals, preferably bronze, brass, copper, aluminum or alloys.   9) Cooling structure according to one   claims 1 to 8, characterized in that one of the   two cover plates (1) is made as a plate   support for cooling channels.    ) Cooling structure according to one   Claims 1 to 9, characterized in that the channels   cooling are carried out as cooling tubes dissement.   11) Cooling structure according to one   claims 1 to 10, characterized in that the parts   these connections for cooling channels or ex-   cooling pipe ends (4), exceed one   cover plates forming a bend.   12) Use of the cooling structure   according to one of claims 1 to 11, as than heat exchange element.   13) Use of the cooling structure   according to one of claims 1 to 11 as an element   actively cooled by hydrogen   a stream of hot gas preferably from a hypersonic engine nism.   14) Method for manufacturing the structure of   cooling arrangement according to one of claims 1 to 13,   characterized by the following process steps: a) producing a support plate (1) of heat-conducting material with bores (2) for receiving connecting pieces for cooling channels or ends (4) of cooling tubes (3). )   b) covering the support plate with a first layer of   by providing joining surfaces in the edge region of the support plate or holes (2),   c) introducing cooling tubes (3) with ex-   tubular elbows (4) or a structure of   in the holes (2) and   (d) filling the spaces between the cooling tubes or the cooling channels with other layers of fibers to form a central layer,   e) assemble the support plate into a cooling structure   by enclosing the central layer with a that of recovery (11).   15) The method of claim 14, wherein   in that, before assembly, the registration plate   cover (11) is covered with a fiber layer by sparing the assembly surfaces in the edge area.   16) Process according to claims 14 or 15,   characterized in that, prior to assembly, the hollow spaces of the fiber structure are filled with matrix metal of material of the same type as that of the plate support (1).   17) Method according to one of claims 14   16, characterized in that hollow spaces of the   fibrous structure are filled by backfilling, infiltrating   tion, pulverulent distribution or deposit of matrix metal.   18) Method according to one of claims 14   17, characterized in that the connecting pieces or pipe ends (4), during assembly, are   related to the drilling of the support plate in to gas.   19) Method according to one of claims 14   at 18, characterized in that the central layer, when the assembly is evacuated.    Method according to one of claims 14   19, characterized in that the assembly of the plate   covering (11) and the support plate (1)   the central layer, takes place by welding or wise.   21) Method according to one of claims 14   20, characterized in that the core layer after assembly is evacuated at   heating to ensure the degassing of this central layer tral.   22) Method according to one of claims 14   21, characterized in that after assembly the layer   central cooling structure is com-   with the central layer evacuated by pressing isostatic hot.