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
  • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D9/0031—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by paired plates touching each other
• • 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
  • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
  • F28F13/08—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media by varying the cross-section of the flow channels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/12—Elements constructed in the shape of a hollow panel, e.g. with channels
  • F28F3/14—Elements constructed in the shape of a hollow panel, e.g. with channels by separating portions of a pair of joined sheets to form channels, e.g. by inflation

Definitions

• WO 98/16786 discloses a heat exchanger in which modules defining a first path for a first fluid, each comprise two sheets forming between them a sheet of channels being fluidly parallel to each other. Each channel interposed between two neighboring channels of the web is. over its entire developed length, - adjacent to these two neighboring channels from which it is isolated by two respective weld lines connecting the two sheets. A second path for a second fluid is defined between the modules, in the interior volume of a box containing the modules.
• the modules are manufactured from two flat sheets, which are connected together by welding lines comprising the above lines isolating the neighboring channels from each other, then a liquid is introduced between the two sheets. pressure producing swelling of the two sheets between the weld lines, which forms the channels.
• the channels of the same module are fluidly in parallel between two distribution zones common to all the channels of the same module, themselves connected to connection boxes.
• the swelling is limited in the distribution zones so that in operation the second fluid penetrates more easily into pseudo-channels formed between the modules neighbors in the hollows between successive swollen zones. Outside these zones with limited swelling, the profile of the channels is continuous and even uniform.
• the flow sections for fluids are only modified locally at the inlet and at the outlet.
• the transition between the area with a modified passage section and the area with a constant passage section along the canals is abrupt and localized.
• WO 01/07 854 describes an improvement according to which the channels are U-shaped instead of being rectilinear.
• DE-A1-196 39 115 describes a plate-shaped heat transfer element consisting of two sheets defining between them channels for an exchange fluid. In the embodiments described with reference to FIGS.
• each channel has a general U-shaped configuration which is subdivided twice in succession so that the passage section varies progressively in a ratio of 1 to 4 from one end to the other of the branched canal.
• Each channel thus folded back on itself and branched occupies a rectangular space, the rectangular spaces being contiguous to each other by their adjacent lengths.
• the purpose of this arrangement is to reduce the speed of the internal fluid when it has almost completed its exchange process, to better exchange the calories in the areas where the two exchange fluids have a small temperature difference between them.
• the indicated application is a cooling element for high temperature batteries for electric vehicles. Such an exchanger is particularly complex to produce, and its flow rate is very limited.
• the object of the present invention is to propose a heat exchanger allowing, without significant additional cost, to control the evolution of the flow rates of at least one of the exchange fluids, in particular when this fluid undergoes an at least partial change. phase, for example condensation, during the flow.
• Another object of the invention is to provide a heat exchanger with low pressure drops distributed in a controlled manner.
• Another object of the invention is to propose a heat exchange module which can compose such an exchanger.
• the heat exchanger in which modules defining a first path for a first fluid each comprise two sheets forming between them a sheet of channels lying fluidly in parallel with each other, each channel interposed between two neighboring channels of the sheet being, over its entire developed length, adjacent to these two neighboring channels from which it is isolated by two respective weld lines connecting the two sheets, and a second path for a second fluid is defined between the modules, is characterized by a overall variation in cross-section along at least one of the paths, with continuity of profile of the channels.
• the overall section variations can be obtained according to the invention by channels of different hydraulic diameters, by channels whose hydraulic diameter varies progressively from one end to the other, and / or by a relative arrangement of the modules which varies the hydraulic diameter of the passage between the modules for the second fluid, and / or etc.
• a hydraulic diameter of a passage for a fluid is called the diameter of a theoretical cylindrical tube offering the same resistance to the flow as the passage considered having a circular non-cylindrical profile.
• the heat exchange module comprising two sheets forming between them a sheet of continuous profile channels lying fluidly in parallel with each other, each channel interposed between two neighboring channels of the sheet being , over its entire developed length, adjacent to these two neighboring channels from which it is isolated by two respective weld lines connecting the two sheets, is characterized by an overall variation in the passage section defined by the channels with continuity of profile of the channels.
• FIG. 1 is a perspective view, with parts broken away, of a plate heat exchanger, with vertical flow with parallel currents;
• - Figure 2 is a perspective view of a cross-current plate exchanger, the flow in the modules -or plates- being vertical;
• - Figure 3 is a perspective view of a plate condenser arranged in vertical planes, with rising gas flow;
• FIG. 4 schematically represents, in perspective, two modules according to a first embodiment of the invention
• - Figures 5 to 8 are views similar to a part of Figure 4 but showing four other embodiments of the invention
• - Figure 9 is a schematic sectional view of a heat exchange module according to yet another embodiment, during its manufacture by hydroforming in a matrix
• - Figure 10 is a view of a variant for producing a half-matrix
• - Figure 11 is a perspective view of a heat exchange module according to yet another embodiment
• - Figures 12 and 13 show in elevation two embodiments for a bundle of modules according to Figure 11
• - Figure 14 shows schematically in perspective a beam obtained with modules according to a variant of Figure 11
• FIG. 15 is a view of another embodiment of a bundle of modules for a heat exchanger according to the invention.
• the heat exchanger comprises a box 1 having a rectangular profile with vertical axis, containing a stack of heat exchange modules 2, in the general form of plates, extending in vertical planes .
• Each module 2 is essentially formed by two sheets 3 which are welded together along vertical weld lines 4 and which are swollen between these weld lines 4 to define vertical channels between them 6.
• Each channel extends with a continuous profile over the entire height of the module. All the channels 6 open at each end, upper and lower respectively, in a upper connection chamber 7 defined in an upper connection box 8, or respectively in a lower connection chamber 9 defined in a lower connection box 11.
• the channels 6 together constitute a first exchange path for a first fluid and this first exchange path can, in service, be connected by the connection boxes 8 and 11 with an external circuit for this first fluid.
• the sealed connection of the channels 6 with the chambers 7 and 9 is provided by suitably shaped bars 12 which are interposed between the ends of the modules 2 and together form a bottom for the connection box 8 or respectively 11.
• the channels 6 are therefore fluidically in parallel with each other between the two connection chambers 7 and 9.
• Each channel 6 other than the two extreme channels of the channel sheet of each module is adjacent over its entire developed length to two neighboring channels, while being isolated of these two neighboring channels by a respective weld line 4 which is continuous over the entire developed length of the channel.
• the developed length is the same as the overall length.
• a second path for a second exchange fluid is defined between the modules 2.
• the entry and exit in this second path is done by second connection boxes 13 and 14 placed on the side wall of the box 1 so that their interior chamber 16 and respectively 17 communicates with the intervals 18 between the sections of the modules 2, on the side of the ends 19 of the bars 12 which is opposite to the connection chamber 7 or 9.
• connection box 13 its periphery is welded in a sealed manner to the periphery 22 of a rectangular opening formed in the box 1.
• One side 21 of the periphery 22 is formed by the ends 19 aligned.
• a second exchange fluid flows between the connection boxes 13 and 14 via a second exchange path constituted by the interior space of the box 1 located between the modules 2.
• the lateral connection box 13 is located in the upper part very close to the upper connection box 8 for the first path, while the lateral connection box 14 is placed in the lower part of the box 1 very close to the lower connection box 11 of the first trip.
• the second fluid enters laterally between the modules, flows between the modules parallel to the channels 6, then exits laterally through the other connection box.
• Each of the two fluids can flow upward or downward depending on the application.
• Called "counter-current" exchanger a parallel current exchanger in which the two fluids flow in opposite directions, therefore one upwards and the other downwards in this example.
• connection boxes for the second fluid 13 and 14 are placed below and above the box 1 so that the direction of flow of the second fluid is vertical between the modules 2.
• it is a condenser.
• the lower connection box 13 comprises an inlet 23 for a gas and the upper connection box 4 comprises an outlet 24 for the residual gas part of the incoming flow 23.
• a cooling fluid such as for example cold water
• the condensable part of the second fluid forms droplets which fall into a bottom 26 of the box 13 then are discharged through a lower liquid outlet 27.
• the second fluid has a volume flow which decreases from the inlet 23 towards the outlet 24 since the initial gas volume decreases as a part of this gas condenses. Therefore, if the passage section of the second path is substantially the same along this second path between the inlet connection box 13 and the outlet connection box 14, the flow speed will decrease. If this speed is suitable for entering the second route, it will be too low for a good exchange near the exit. If on the contrary, the speed is appropriate in the vicinity of the outlet, it will be too high at the inlet and the gas will tend to entrain droplets towards the outlet, contrary to the desired separation effect.
• each module 102 comprises channels 6 a , 6 b , 6 C , 6 a having different hydraulic diameters.
• the pitch of the weld lines 4, that is to say the distance between weld lines 4 successive is equal to a constant called P Q.
• the difference in hydraulic diameter between neighboring channels is obtained by a difference in the swelling of the sheets 3 in each zone defining a channel, the channels 6 a to 6 d having respective amplitudes of inflation G a to G d , which increase by one edge. to the other of the module 102.
• the profile and consequently the hydraulic diameter of each channel 6 a , 6 b , 6 C or 6 d are constant over the entire length of this channel.
• each module 202 comprises groups of channels having identical hydraulic diameters, these diameters however being different from a group with the other.
• there are two groups of each two channels namely the lower group of channels 6 a , 6 b with a relatively small identical hydraulic diameter, and the upper group of channels 6 C and 6 d with a relatively large identical hydraulic diameter.
• the second path 28 comprises a first hydraulic diameter between the channels 6 a and 6 b of the neighboring modules 202, and a second smaller hydraulic diameter between the neighboring channels 6 C and 6 d .
• FIG. 6 which will only be described for its differences from that of FIG. 5, there is between the two groups of channels 6 a , 6 b and 6 C , 6 d an intermediate channel 6 e having a swelling G e of intermediate value between that, weaker, of channels 6 a and 6 and that, stronger, of channels 6 C and 6 d .
• the hydraulic diameter of the channels 6 e is intermediate between that of the channels 6 a , 6 and that, larger, of the channels 6 C , 6 d .
• the second path 28 has between the channels 6 e of the neighboring modules 302 an intermediate value between that larger defined between the channels 6 a and 6 b and that, weaker, defined between the channels 6 C and 6 d .
• the pitch P 0 between the weld lines 4 was the same for all the weld lines of a module and for all the modules.
• the inflations G 0 are the same for all the channels of all the modules 402.
• the channels of a web comprise a first group of channels 6 g and a second group of channels 6 a.m.
• the pitch P g between two weld lines defining between them a channel 6 g is greater than the pitch P h between two weld lines defining between them a channel 6 h .
• the hydraulic diameter of the path 28 decreases when the pitch of the weld lines decreases.
• the example shown in Figure 8 combines variations in pitch and swelling.
• the figure 9 illustrates the hydroforming step to produce a module with four groups of channels 6 P , 6 q , 6 r , 6 S having different hydraulic diameters resulting at least in part from different swellings.
• the planar blank of the module is placed, constituted at this stage of two flat sheets welded to each other, for example by laser, along the weld lines such as 4 of the figures previous, between two matrices 31, 32 defining between them a cavity with working faces 33 p , 33 q , 33 r , 33 s and respectively 34 p , 34 q , 34 r 34 s between which the blank of the module extends and which have between them, two to two, a distance corresponding to the desired swelling in each region respectively.
• FIG. 10 illustrates a less costly tooling where each die (only the lower die 31 is shown) has a flat working face 33 corresponding to the maximum inflation expected, and shims 36 p , 36 q , 36 s to define the zones where less swelling is desired.
• these shims must be fixed under the working surface of the die to avoid their fall by gravity before the hydroforming step. Attachment of shims is also desirable for the lower die.
• the invention makes it possible to vary the hydraulic diameters in a first direction, for example in the direction of growth, for example between groups 6 P and 6 q or 6 q and 6 r , then in the second direction, here the direction of decrease between the group 6 r and 6 S , when this is desired to optimize the exchanger.
• the weld lines 4 of a module are mutually parallel and the hydraulic diameter of a channel is constant over its entire length.
• the weld lines 604 of a module 602 are all convergent, in this example towards the same point located beyond one of the ends of the module.
• the neighboring weld lines form a relatively small angle between them, designated by A in FIG. 11.
• the pitch between successive weld lines increases from one end to the other of each channel, as does the hydraulic diameter of the channel.
• Such a module has a general isosceles trapezoidal shape, with oblique longitudinal edges 37 which are substantially parallel to the two extreme weld lines 604 of the channel sheet.
• Such a module is useful for producing a condenser in a configuration according to FIG. 1 or FIG. 2, that is to say with the vertical channels. If the wide end of the channels is oriented upwards, the fluid to be condensed can follow a downward path in the channels where it meets an increasingly smaller hydraulic diameter as its volume is reduced by condensation.
• the second fluid passes between the modules, or else forms a bath between the modules.
• an ascending flow evaporator can also be produced, the first fluid encountering increasing hydraulic diameters as its volume increases due to the evaporation.
• Such a module can also be arranged with the large end of the channels downwards to produce, for example, a reflux condenser, that is to say with, as described previously with reference to FIG. 3, an upward evaporating flux and formed droplets which flow back down into a recovery arrangement.
• the swelling of the channels can be constant along each channel, or on the contrary grow from the narrowest end to the widest end of each channel.
• FIG. 12 shows in elevation a bundle of modules 602 with channels whose swelling increases from bottom to top and where the modules are in parallel vertical planes.
• modules 602 identical to those of FIG. 12 are placed in planes which converge towards a point situated beyond the narrow end of the channels, so as to reduce the hydraulic diameter of the second path on the side where the ends of the channels are narrow, with respect to the embodiment of FIG. 12.
• FIG. 14 very schematically represents the bundle when the inflation is constant along each channel of the modules according to FIG. 11.
• the bundle takes the shape of a hexahedron of which two opposite faces are isosceles trapezoids in parallel planes.
• a box for such a beam typically takes a corresponding shape, with two opposite parallel faces in the form of an isosceles trapezoid and two rectangular faces connecting the oblique sides of the trapezoids. If, moreover, the swellings of the channels are variable as illustrated in FIGS. 12 and 13, the bundle takes the general form of a truncated pyramid, that is to say that the two trapezoidal faces are inclined with respect to the other and the other two lateral faces also become trapezoidal.
• the box typically takes a corresponding shape.
• the modules 702 have all identical channels having the same widths and the same swellings over their entire length.
• modules are arranged in a fan shape with respect to each other, therefore in oblique planes with respect to each other, converging beyond one end of the channels, so that the hydraulic diameter of the second path, assumed to be co- current or counter-current, varies from one end to the other. It is also possible, not shown, to orient the modules relative to each other in a fan shape by relative pivoting about an axis parallel to the weld lines, therefore to the longitudinal direction of the channels, in order to produce a variable hydraulic diameter of the second path when the exchanger is cross current.
• the modules 2 are offset with respect to each other in their own plane so that the corrugation peaks of a module are located opposite the corrugation valleys of the two neighboring modules.
• the invention is particularly applicable with the following dimensions: -developed length of the channels: 0.5 to 10 m -width of the channel strip: 0.15 to 2 m - no succession of modules: 8 to 105 mm - no succession of weld lines: 10 to 100 mm - swelling of the channels: 5 to 80 mm measured inside channels.
• the sheets are typically made of stainless steel with a thickness of a few tenths of a millimeter (not limited to more than 10/10) knowing that a thin sheet promotes heat exchange but that the pressure differences between the two fluids and the thermal stresses must also be taken into account.
• the invention is not limited to the examples described and shown.
• the hydraulic diameter variation means described can be combined in very many ways.

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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)

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• 2004
  • 2004-01-12 FR FR0400210A patent/FR2865028B1/fr not_active Expired - Fee Related
• 2005
  • 2005-01-12 JP JP2006548348A patent/JP2007518053A/ja active Pending
  • 2005-01-12 US US10/585,601 patent/US20090183862A1/en not_active Abandoned
  • 2005-01-12 EP EP05717403A patent/EP1709380A1/de not_active Ceased
  • 2005-01-12 WO PCT/FR2005/000068 patent/WO2005073657A1/fr not_active Ceased

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