EP3394555A1

EP3394555A1 - Heat exchanger, notably for motor vehicle

Info

Publication number: EP3394555A1
Application number: EP16829107.8A
Authority: EP
Inventors: Jérôme MOUGNIER
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2015-12-21
Filing date: 2016-12-16
Publication date: 2018-10-31
Also published as: FR3045807B1; WO2017109350A1; FR3045807A1

Abstract

The invention relates to a heat exchanger, notably for motor vehicle, comprising: – a heat exchange core bundle (3) with a plurality of heat exchange tubes (5), and – at least one fluid header tank (19). According to the invention, the heat exchange core bundle (3) comprises an alternating stack of a plurality of first frames (13) and of inserts (15), such that: – each first frame (13) accepts at least a first and a second heat-exchange tube (5), and comprises:.first means (131) of placing the first heat exchange tube (5) in fluidic communication with the fluid header tank (19) and .second means (131) of placing the second heat exchange tube (5) in fluidic communication with the fluid header tank (19), and – the inserts (15) also respectively have at least one turning-back orifice (155) arranged in fluidic communication with both a first and a second means (131) of placing at least a first frame (13) in fluidic communication with respect to the insert (155).

Description

Heat exchanger, in particular for a motor vehicle

The invention relates to the field of heat exchangers and in particular to heat exchangers intended to be traversed by a fluid under high pressure.

In this respect, the invention relates more particularly to heat exchangers able to be traversed by a refrigerant fluid having a relatively high operating pressure, as is the case with natural gases such as carbon dioxide designated by CO ₂ , having an operating pressure higher than the refrigerant gases used in the solutions of the state of the art.

Such heat exchangers find particular application in motor vehicles. They may in particular constitute a gas cooler in which the cooling fluid such as CO ₂ is cooled by a second fluid, such as liquid. Conversely, the second fluid can be cooled by the first fluid for example in gaseous form, the heat exchanger is then commonly referred to as "Water chiller" in English.

Such heat exchangers can in particular be used in the thermal regulation of one or more batteries of an electric or hybrid vehicle. The thermal regulation of the batteries is an important point because if the batteries are subjected to temperatures too cold, their autonomy can decrease strongly and if they are subjected to too high temperatures, there is a risk of thermal runaway up to to the destruction of the battery, or even the motor vehicle. In order to regulate the temperature of the batteries, it is known to use a coolant, generally coolant comprising a mixture of brine, which circulates in a heat exchanger in contact with the battery or batteries. The cooling liquid can thus bring heat to the battery or batteries to heat them, this heat having been absorbed by the cooling liquid for example during the heat exchange with the C0 ₂ flowing in the gas cooler. The coolant can also, if necessary, absorb the heat emitted by the battery or batteries to cool them and remove this heat at one or more other heat exchangers. Such heat exchangers can also be used like any other gas cooler in an air conditioning circuit.

These heat exchangers can in particular be heat exchangers assembled by soldering.

Heat exchangers are known, for example, comprising a stack of plates allowing the circulation of the first fluid, such as the refrigerant or refrigerant gas, and the second fluid such as the cooling liquid.

However, the use of a cooling fluid such as C0 ₂ under a very high pressure, generally greater than 100 bar, with a burst pressure which can reach, for example, up to 340 bar, implies that heat exchangers such as gas coolers must withstand such high pressures.

Plate heat exchangers known from the prior art do not allow to withstand such high pressures.

In order to remedy this, heat exchangers comprising a stack of tubes interconnected by at least one collector of the first fluid, in particular the refrigerant fluid on each side of the tubes, and the second fluid, for example, are known from the prior art. in liquid form, can circulate around the tubes in an envelope connected to a water box.

However, such an architecture is complex to achieve and in particular has drawbacks in terms of sealing, particularly in the case of a brazed heat exchanger for which it proves necessary to provide multiple soldering points for several pieces of the heat exchanger. In addition, with this architecture, the two fluids circulate generally at cross flow. It is not always possible to provide a flow against the current or in several passes of the two fluids, which limits the efficiency of the heat exchanger. In addition, it is difficult to reduce the tube height below 2mm due to the known design of the collector receiving the ends of the tubes, which also limits the efficiency of the heat exchanger. It has also been found that such a heat exchanger does not always have good mechanical strength.

Moreover, a constant problem of heat exchangers implemented in a motor vehicle resides in the allocation of a reduced space, in order to meet the requirements of the manufacturers.

The present invention aims to improve the solutions of the state of the art and to at least partially solve the disadvantages described above by providing a simple heat exchanger to achieve whose thermal performance is improved.

For this purpose, the subject of the invention is a heat exchanger, in particular for a motor vehicle, said exchanger comprising:

a heat exchange bundle with a plurality of heat exchange tubes defining circulation channels for a fluid, and

at least one manifold of the fluid.

According to the invention, the heat exchange bundle comprises an alternating stack of a plurality of first frames and spacers, such as:

each first frame receives at least a first and a second heat exchange tube, and comprises:

First means for fluidic communication of the first heat exchange tube with the fluid collection box and

Second means for fluidic communication of the second heat exchange tube with the fluid collection box, and the spacers additionally have at least one overturning orifice arranged in fluid communication with both a first delivery means in fluid communication and a second means for fluidic communication of at least a first frame opposite the spacer,

so as to allow the fluid emerging from a first heat exchange tube to overturn in the overturning orifice and flow to a second heat exchange tube adjacent in a first frame.

The spacers thus shaped ensure the overturning of the fluid in a simple manner to allow a circulation in several passes of the fluid which circulates in the circulation channels of the first frames 13 of the floors above and below said tabs.

In addition, the means for placing in fluid communication provided on the first frames make it possible to collect the fluid, such as a refrigerant fluid, and to distribute it in the heat exchange tubes held in these first frames, in a simple manner. It is no longer necessary to provide the collectors on each side of the tubes as in the known solutions.

In the invention, the frames designate a part, or an assembly of parts, which can be rigid, delimiting a closed space or not. In this space can be positioned, in our example, heat exchange tubes.

It will be noted that the heat exchange bundle, which comprises a plurality of heat exchange tubes, is distinct from the frames.

The heat exchanger may further comprise one or more of the following features taken alone or in combination.

According to a particular embodiment, each first frame is adapted to receive a first and a second heat exchange tubes communicating with one another at one end, via the reversal orifice arranged on one side of the ends of the two exchange tubes. thermal, for a "U" circulation of the fluid.

According to one aspect of the invention, the turning orifice has a substantially longitudinal shape, preferably substantially oblong.

According to an advantageous embodiment, the turning orifice extends longitudinally substantially perpendicular to the general direction of the flow of fluid in the circulation channels of the heat exchange tubes.

According to another aspect of the invention, the spacers are made in the form of second frames.

The heat exchange bundle thus comprises an alternating stack of first frames for receiving the heat exchange tubes and second frames.

The heat exchanger thus comprises a stack of simple elements, namely frames and heat exchange tubes in which circulates a fluid, such as a refrigerant, inserted in the first frames, and between which can flow a second fluid such as coolant. Such an architecture allows a simpler realization of the heat exchanger as a whole.

According to an additional aspect, the turning orifice is provided on at least one edge of each second frame extending substantially perpendicularly to the general direction of the flow of fluid in the circulation channels of the heat exchange tubes.

According to a further aspect, the second frames have fluid passage guides, such as through-passage orifices, provided on at least one edge of each second frame and communicating with the means for placing the first frames in fluid communication, in such a way that to allow the flow of fluid through the stack.

According to one embodiment, the passage guides are arranged in alignment with the means for placing the first frames in fluid communication.

The superposed frames make it possible to create the flow path of the fluid such as a refrigerant fluid, when the frames are assembled, for example by soldering, and likewise the superposed frames make it possible to create the flow path of another fluid. such as a coolant between the heat exchange tubes.

According to yet another aspect of the invention, each first frame further has a partition wall between two heat exchange tubes, and the reversal orifice extends on both sides of the partition wall when a first frame and an interlayer are stacked.

According to one embodiment, the partition wall extends along the entire length of the heat exchange tubes.

In a particular aspect, the partition wall extends longitudinally substantially parallel to the direction of the circulation channels of the heat exchange tubes.

Advantageously, the partition wall of a first receiving frame is made in one piece with the first receiving frame.

According to a further aspect of the invention, the fluid able to circulate in the circulation channels of the heat exchange tubes is a cooling fluid, such as C0 ₂ , intended to circulate at high pressure, especially at a pressure greater than 100 bar.

The heat exchanger has a better mechanical strength compared to the solutions of the prior art and very good resistance to high pressures, in particular due to the circulation of C0 ₂ as a refrigerant.

According to yet another aspect of the invention, the heat exchanger allows a heat exchange between a first fluid able to circulate in the circulation ducts of the heat exchange tubes and a second fluid able to circulate between the heat exchange tubes. and the heat exchanger is configured for circulation in at least two passes of the first fluid and the second fluid.

Other features and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings among which:

FIG. 1 is a perspective view of a heat exchanger,

FIG. 2 is a partial perspective view of a stack of first frames and second frames of the heat exchange bundle of the heat exchanger of FIG. 1;

FIG. 3 is another perspective view of a stack of first frames and second frames of a heat exchange bundle,

FIG. 4 schematically represents a first frame of the heat exchange bundle receiving two heat exchange tubes,

FIG. 5 is a view of the first single frame of FIG. 4,

FIG. 6 schematically represents a second frame of the heat exchange bundle, and

FIG. 7 is another partial perspective view of the stack of first frames and second frames of the heat exchange bundle showing a first frame receiving two heat exchange tubes communicating at one end.

In these figures, substantially identical elements have the same references. The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments.

In the present, the terms upper and lower, or high and low, or vertical and horizontal, are designated with reference to the arrangement of the elements in the figures. This arrangement corresponds to the inverted arrangement of the elements in the mounted state in a motor vehicle in particular.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment.

Simple features of different embodiments may also be combined to provide other embodiments.

In the present, the terms upper and lower, or high and low, or vertical and horizontal, are designated with reference to the arrangement of the elements in the figures. This arrangement corresponds to the arrangement of the elements in the assembled state in a motor vehicle in particular.

Heat exchanger

With reference to FIG. 1, the invention relates to a heat exchanger 1, in particular for a motor vehicle, for a heat exchange between at least a first fluid and a second fluid.

The first fluid can enter the heat exchanger 1 in gaseous form and the second fluid in liquid form.

It is in particular a heat exchanger assembled by brazing.

To do this, the heat exchanger 1 has at least partially, that is to say say on at least some elements or parts, a coating intended to melt to join the elements of the heat exchanger during assembly by soldering.

The coating is commonly referred to as "clad" in the field of brazing metal parts, in particular aluminum. In particular, the coating is added to the core of the parts, during manufacture, for example by cold rolling.

It may be a non-limiting example of a coating comprising aluminum and silicon.

The heat exchanger 1 according to the invention is particularly suitable for the circulation of at least one fluid having a high operating pressure, in particular greater than 100 bar.

For example, the first fluid is a refrigerant intended to circulate at high pressure such as C0 ₂ , also designated R744 according to the industrial nomenclature.

The heat exchanger 1 can in particular be a gas cooler in which the cooling fluid such as CO ₂ is cooled by a second fluid for example in liquid form, such as cooling liquid comprising a mixture of brine.

The second fluid such as the coolant can also be cooled by the first fluid such as CO ₂ , such a heat exchanger is then commonly referred to as "Water chiller" in English.

The heat exchanger 1 comprises a heat exchange bundle 3 for the heat exchange between the first fluid and the second fluid. In the illustrated example, the heat exchange bundle 3 has a generally parallelepipedal shape.

The circulation of the first and second fluids is advantageously countercurrent in the heat exchange bundle 3.

The introduction and the evacuation of the first fluid in the heat exchange bundle 3 or outside the heat exchange bundle 3 is shown schematically by way of example by the arrows Fli for the introduction and Fl ₀ for the evacuation.

Similarly, the introduction of the second fluid into the exchange beam 3 and the evacuation of the second fluid out of the heat exchange bundle 3 is shown schematically by way of example by the arrows F2i for the introduction and F2o for the evacuation.

Finally, the heat exchanger 1, and more specifically the heat exchange bundle 3, may be configured for circulation in at least two passes of one of the two fluids, in particular the first fluid, or both fluids.

An example of circulation of the two fluids against the current and in two passes is illustrated schematically by the arrows F1 and F1 in FIG.

More precisely, the heat exchange bundle 3, better visible in FIGS. 2 and 3, comprises a plurality of heat exchange tubes 5 (see FIG. 2) stacked so as to alternately define first circulation channels (not visible on the figures) for the first fluid in the heat exchange tubes 5 and the second circulation channels 9 for the second fluid between the heat exchange tubes 5.

The heat exchange tubes 5 are preferably made by extrusion.

The heat exchange tubes 5 can be made in the form of flat tubes, advantageous in terms of space.

The flat tubes 5 have a generally rectangular general shape, with a length for example of the order of 32 mm and a thickness of about one millimeter.

The thickness is here considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the heat exchange tubes 5. In other words, it is the thickness in the direction of stacking heat exchange tubes 5.

Each heat exchange tube 5 defines a predetermined number of first circulation channels (not visible in the figures) for the first fluid, in particular micro-flow channels for the first fluid.

The first channels or micro-channels (not shown in the figures) extend here substantially longitudinally, in a substantially "I" or rectilinear shape. The first circulation channels or micro-channels (not visible in the figures) for the first fluid allowing the flow of the first fluid respectively extend respectively in a direction parallel to the longitudinal direction of the heat exchange tubes 5. The first fluid can follow a circulation in at least two passes called "U" circulation as will be described later.

The second circulation channels 9 for the second fluid may be shaped to allow circulation in a so-called "I" flow but also a circulation in two passes known as "U" circulation as will be described later.

Turbulators 11 of the flow of the second fluid are advantageously arranged in the second circulation channels 9, thus improving the heat exchange between the two fluids.

The turbulators 11 may be carried by an element 12 distinct from the heat exchange tubes 5 as illustrated in FIG. 2. The turbulators 11 have, for example, a substantially crenellated shape.

Tabs 15 are advantageously arranged between the heat exchange tubes 5 and define the pitch between the heat exchange tubes 5.

According to one embodiment, the heat exchange bundle 3 comprises an alternating stack of first frames 13 and spacers 15.

According to the embodiment described, a plurality of second spacer frames 15 are arranged between two first frames 13 for receiving the heat exchange tubes 5. The second frames 15 are also called spacer frames.

The stack is here substantially vertically.

Each first frame 13 is able to receive at least two heat exchange tubes 5 and this assembly forms a stage of the heat exchange bundle 3. The first frames 13 can be designated by tube frames.

Each second frame 15 can receive turbulators 11 and this assembly forms another stage of the heat exchange bundle 3.

These two sets or stages are repeated as many times as necessary depending on the space available and the performance to be achieved. The first frames 13 and the second frames 15 are described in more detail below.

For example, closures plates 17, 18 (see Figure 1), in particular at least one lower closure plate 17 and at least one upper closure plate 18 may be arranged on either side of the stack of first frames 13 and second frames 15 so as to close the exchange beam 3. The closure plates advantageously have a shape complementary to the shape of the first frames 13 and the second frames 15.

The heat exchanger 1 further comprises at least one manifold 19 of the first fluid arranged in fluid communication with the first circulation channels (not visible in the figures).

The collecting box 19 is according to the illustrated example arranged on an upper closure plate 18 disposed at the top of the heat exchange bundle 3.

The heat exchanger 1 further comprises at least two inlet and fluid outlet pipes 21 for introducing and evacuating the second fluid. In this example, the two tubes 21 are arranged on the same upper closure plate 18 as the manifold 19 for the first fluid.

Of course, according to a variant not illustrated, it is possible to arrange the two pipes 21 on the bottom plate 17.

According to another variant not illustrated, provision can be made to separately arrange the pipes 21 with a pipe 21 on the upper plate 18 and the other pipe 21 on the bottom plate 17.

In particular, the manifold 19 can be arranged on one side of the heat exchange bundle 3 and the tubes 21 can be arranged on the other side of the heat exchange bundle 3, thus allowing a counter-current circulation of two fluids.

According to the arrangement illustrated in Figure 1, the manifold 19 is arranged on the left while the pipes 21 are arranged on the right.

First frames called tubes-frames

With reference to FIGS. 2 and 4 and 5, the first frames 13 for receiving the heat exchange tubes 5 are now described in greater detail.

The first frames 13 may be at least partially made of aluminum.

The first frames 13 present:

two opposite edges 13A, 13B (see Figures 4 and 5) extending perpendicular to the direction of the first channels (not visible in the figures) of circulation of the first fluid, in other words here perpendicularly to the longitudinal direction of the tubes of heat exchange 5, and

two other opposite edges 13C, 13D extending parallel to the direction of the first channels (not visible in the figures) of circulation of the first fluid, in other words here in parallel with the longitudinal direction of the heat exchange tubes 5.

It is also possible to define the first frames 13 with respect to the general direction of flow of the first fluid, namely that the first frames 13 have:

two opposite edges 13A, 13B extending perpendicularly to the general direction of flow of the first fluid, and

two other opposite edges 13C, 13D extending parallel to the general direction of flow of the first fluid.

The general direction of flow of the first fluid means the direction of circulation for each pass of the first fluid, for example the direction of the branches of the "U" in the case of a circulation in two passes called circulation in " U "of the first fluid.

In the illustrated example, the first frames 13 are of generally rectangular shape and have two longitudinal edges 13C, 13D, forming long sides, extending substantially parallel to the general direction of flow of the first fluid and two edges lateral sides 13A, 13B, forming narrow sides, extending in the width direction, substantially perpendicular to the direction of flow of the first fluid.

However, according to other embodiments, one could provide frames having a general shape that is not rectangular, for example elliptical, or diamond-shaped. The longitudinal axis of the first frames 13 and heat exchange tubes 5 is here confused.

These first frames 13 have the same thickness as the heat exchange tubes 5 they receive, in particular of the order of a few millimeters, for example of the order of 1mm.

As before, the thickness is considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the first frames 13. In other words, it is the thickness in the direction of stacking frames 13, 15.

Each first frame 13 is able to receive at least two heat exchange tubes 5 allowing circulation in at least two passes of the first fluid. For this purpose, each first frame 13 has at least two housings 130 to each receive an associated heat exchange tube 5.

According to the illustrated embodiment, each first frame 13 is able to receive two heat exchange tubes 5, each heat exchange tube 5 being received in a housing 130 associated.

The heat exchange bundle 3 then has two rows of heat exchange tubes 5: a first row of first heat exchange tubes 5 and a second row of second heat exchange tubes 5.

In addition, two adjacent heat exchange tubes 5 received in one and the same frame 13 communicate with each other at one end so as to allow two-pass circulation of the first fluid.

The heat exchange bundle 3 thus has at least one reversal zone of the first fluid, that is to say, allowing the first fluid having circulated in a heat exchange tube 5 to circulate to another heat exchange tube 5, namely the adjacent heat exchange tube 5 received in the same first frame 13. Of course, it is possible to provide more than two heat exchange tubes 5 for a circulation of the first fluid in addition to two passes in a first frame 13.

Fluidic communication at one end of two adjacent heat exchange tubes 5 received in a first frame 13 is advantageously provided by a second frame 15 as will be described in more detail later.

In order to allow the flow of the first fluid in the heat exchange bundle 3, the first frames 13 comprise means for placing in fluid communication 131 the first circulation channels (not visible in the figures) of the heat exchange tubes 5 with the collector box 19.

The fluid communication means 131 of each first frame 13 are thus arranged in fluid communication with the fluidic communication means 131 of the other first frames 13 of the heat exchange bundle 3 and with the manifold 19.

In a complementary manner to the two rows of heat exchange tubes 5, the fluid communication means 131 define two rows respectively associated with a row of heat exchange tubes 5.

Thus, first communication means 131 ensure the fluidic communication of the first heat exchange tubes 5 or in other words the first row of first heat exchange tubes with the manifold 19. And, second means of in communication 131 ensure the fluidic communication of the second heat exchange tubes 5 or in other words the second row of second heat exchange tubes with the manifold 19.

According to the illustrated example, the first frames 13 respectively have a predefined number of recesses 131 forming the means for placing in fluid communication, in which the ends, in particular the longitudinal ends, of the heat exchange tubes 5 open out.

Of course, the number of recesses 131 is adapted according to the number of first channels (not visible in the figures) of circulation of the heat exchange tubes 5.

These recesses 131 are here provided on two opposite edges 13A, 13B of the first frames 13 which are facing the ends of the heat exchange tubes 5. These are the lateral edges of the first frames 13.

The first frames 13 are arranged so that their recesses 131 are in fluidic communication with the recesses 131 of the other first frames 13. Here, the recesses 131 of the first frames 13 are aligned in the direction of the height of the heat exchange bundle 3.

In addition, on one side of the first frames 13, the recesses 131 are aligned with the manifold 19.

According to an advantageous embodiment, at least one lateral edge 13A, 13B of a first receiving frame 13, arranged opposite one end of a heat exchange tube 5, is shaped according to a pattern defining a succession of arches.

The arches are advantageously arranged over the entire width of the lateral edge

13 A, 13B which is opposite the ends of the heat exchange tubes 5 received in the same first frame 13.

In other words, the arches are provided over a width substantially equal to the entire width of the set of heat exchange tubes 5 that a same first frame 13 can receive, here two heat exchange tubes 5.

Arch is understood to mean the group formed by an arch arch 132 connecting two feet of arch 133. In this series of arches, two adjacent arch arches 132 are connected by a common arch foot 133.

According to the illustrated example, a recess 131 is delimited by an arch, in other words each recess 131 is made between two adjacent arch feet 133 and is delimited by these two arches 133 and the arch arch 132 connecting them .

When a heat exchange tube 5 is arranged in a housing 130 of a first frame 13, the space remaining between one end of the heat exchange tube 5 and an arch arch 132 makes it possible to define a through opening of setting in fluid communication.

By way of non-limiting example, the diameter of a through opening is of the order of 0.5 mm.

The arches 133 advantageously provide a stress absorption function. The arches are sized taking into account the mechanical strength of the first frame 13 and the flow of the first fluid through the recesses 131 defined by the arches.

In addition, in the case of a heat exchanger 1 assembled by soldering, the arches 133 still make it possible to define soldering zones with the second frames 15.

Furthermore, in order to allow the flow of the second fluid in the heat exchange bundle 3, the first frames 13 also have guides 134 for the passage of the second fluid.

According to the illustrated example, the first frames 13 are respectively shaped with at least one loop 134 which when a heat exchange tube 5 is arranged in the first frame 13 defines a through through opening allowing the flow of the second fluid.

By way of illustration, the figures show different embodiments of the loops 134, in particular FIG. 1 illustrates a first embodiment of loops 134 of substantially rounded shape, while FIGS. 3 to 5 illustrate a second exemplary embodiment. handles 134 whose contour is more rectilinear shape. Of course, any other form of the handles 134 may be considered.

The handles 134 allow to define the guides for the passage of the second fluid. The handles 134 of each first frame 13 are arranged in alignment with the handles 134 of the other first frames 13 of the heat exchange bundle 3 so as to allow the flow of the second fluid through the bundle 3.

Finally, each first reception frame 13 advantageously has at least one partition wall 135 which compartmentalizes the first reception frame 13.

This partition wall 135 is here arranged in the extension of a foot of arch 133.

According to the particular example described, the partition wall 135 extends longitudinally substantially parallel to the direction of the first channels (not visible in the figures) of circulation for the first fluid in the heat exchange tubes 5.

In the illustrated example, each first receiving frame 13 has a partition wall 135, for example substantially central, which compartmentalizes the first reception frame 13 in two housings 130 for each receiving a heat exchange tube 5.

The partition wall 135 is thus arranged between two heat exchange tubes 5 when they are placed in the first frame 13. The partition wall 135 extends in this example over the entire length of the exchange tubes thermal 5 received in the first frame 13.

The partition wall 135 of a first frame 13 can be made in one piece with this first frame 13. Such a first frame 13 can be made by cutting stamping in a simple manner.

Second frames

With reference to FIGS. 3 and 6, the second frames 15 are now described in more detail.

The second frames 15 forming spacers are respectively arranged between two successive first frames 13, thus defining the pitch between two stages of heat exchange tubes 5 received in respective first frames 13.

The second frames 15 may be at least partially made of aluminum.

When the second frames 15 receive turbulators 11, the second frames 15 are said frames-turbulators or turbulators frames.

Similarly to the first frames 13, the second frames 15 have: two opposite edges extending parallel to the direction of the first channels (not shown) of circulation of the first fluid, in other words here in parallel with the longitudinal direction of the exchange tubes thermal 5, and

- two other opposite edges extending perpendicularly to the direction of the first channels (not shown) of circulation of the first fluid, in other words here perpendicular to the longitudinal direction of the heat exchange tubes 5.

It is also possible to define the second frames 15 with respect to the general direction of flow of the first fluid, namely that the second frames 15 have:

- two opposite edges extending parallel to the general direction of flow of the first fluid, and

two other opposite edges extending perpendicular to the general direction of flow of the first fluid.

In addition, according to the embodiment described, it is still possible to define the second frames 15 with respect to the general direction of flow of the second fluid flowing against the current of the first fluid, namely that the second frames 15 have:

two opposite edges extending parallel to the general direction of flow of the second fluid, and

two other opposite edges extending perpendicular to the general direction of flow of the second fluid.

The general direction of flow of the second fluid means the direction of the circulation in "I" in the case of a circulation in a pass of the second fluid, or the direction of the branches of the "U" in the case of a circulation in two passes of the second fluid.

In the illustrated example, the second frames 15 are of generally similar shape to the first frames 13, here substantially rectangular.

The second frames 15 have two longitudinal edges, forming long sides, extending substantially parallel to the longitudinal edges of the first frames 13 and the general direction of flow of the second fluid, and two lateral edges, forming short sides, extending in the width direction, substantially perpendicular to the direction of flow of the second fluid parallel to the side edges of the first frames 13.

According to the embodiment described, the second frames 15 extend over the same length and the same width as the first frames 13. In particular, the outer contours of the first frames 13 and second frames 15 are substantially identical so that the alternating stacking of the first frames 13 and second frames 15 form a block.

More particularly, each second frame 15 defines an internal width and an internal length L (see FIG. "Internal width" means the width defined between the inner walls of the opposite longitudinal edges. Similarly, the term "internal length", the length defined between the inner walls of the opposite side edges.

In addition, the lateral edges of the second frames 15 may be slightly larger than the lateral edges of the first frames 13, so that the ends of the heat exchange tubes 5 received in the first frames 13 stacked with the second frames 15, rest on the peripheral edge of the lateral edges of the second frames 15.

The second frames 15 therefore define an internal length L less than the internal length defined by the interior space of the first frames 13.

The second frames 15 have a thickness which is of the order of a few millimeters, for example of the order of 0.5mm to 4mm, preferably of the order of 2mm. The thickness is here considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the second frames 15. In other words, it is the thickness in the stacking direction of the frames 13, 15.

Similarly to the first frames 13, the second frames 15 can be made by stamping cut.

According to the illustrated embodiment, the second frames 15 allow circulation in two passes of the second fluid.

For this purpose, the second frames 15 may each comprise a bar

150 arranged within the respective second frame 15 so as to separate two flow passes for the second fluid.

It is therefore an internal bar 150. In the example illustrated, the bar 150 makes it possible to shape the second circulation channel 9 substantially in a "U" shape.

Of course, it would be possible to provide a circulation of the second fluid in addition to two passes in a second frame 15 and for this purpose more than one bar 150 inside the second frame 15 which would be, by way of non-limiting example, arranged in an offset manner and opposite to each other.

The bar 150 extends longitudinally inside a second frame 15. The bar 150 therefore extends in this example substantially parallel to the longitudinal edges of the second frame 15.

To do this, the bar 150 does not extend over the entire internal length L of the second frame 15, as is best seen in Figure 6. In other words, the bar 150 extends from a side edge of a second frame 15 towards the opposite side edge but without reaching the opposite side edge.

The bar 150 is secured to a lateral edge of a second frame 15 and projects with its free end towards the internal space of the second frame 15 towards the opposite side edge, leaving a space.

The inner bar 150 therefore extends longitudinally from a lateral edge of a second frame 15 over a length l less than the internal length L of the second frame 15.

The inner bar 150 does not extend over the entire internal width of the second frame 15. More specifically, the inner bar 150 has a width W smaller than the internal width of the second frame 15.

The width W of the inner bar 150 may be greater than or equal to, preferably greater than, the thickness Th of the second frame 15. Thus, on each side of the bar 150, the input and the output of the path are defined. flow for the second fluid.

The bar 150 may also be called tongue. In addition, the bar 150 is substantially of the same thickness as the second frame 15.

The bar 150 is for example arranged substantially centrally. More specifically, the bar 150 is arranged substantially in the center of a second frame 15 in the width direction of the second frame 15. In this way, the bar 150 divides the second frame 15 into two parts of the same size.

Advantageously, the inner bar 150 extends over a length l at least equal to half the internal length L of a second frame 15.

The inner bars 150 of the second frames 15 are for example arranged facing the partitions 135 of the first frames 13 (Figures 2 and 4 to 5).

Of course, any other means for conforming the second circulation channel 9 in several passes may be envisaged, for example according to a variant not illustrated such means can be provided on a disturbance plate 12 carrying the turbulators 11 of the flow of the second fluid.

Complementarily to the first reception frames 13, the second frames 15 have guides 151 for the passage of the first fluid allowing it to flow in the stack of the first reception frames 13 and the second frames 15.

The guides 151 are here made in the form of through-passage orifices 151 arranged in alignment with the recesses 131 forming fluid communication with the first reception frames 13, delimited here by the succession of arches. The through-passage orifices 151 are thus arranged on at least one lateral edge of a second frame 15.

Of course, the number of throughthrough orifices 151 is adapted as a function of the number of recesses 131 and therefore the number of first channels (not visible in the figures) for circulation of the heat exchange tubes 5.

In addition, the second frames 15 respectively have means for fluid communication 152 of the second circulation channels 9 between them on the one hand and with the pipes 21 for the second fluid on the other hand.

The means of fluid communication 152 provided on the second frames 15 collect the second fluid and distribute it between the heat exchange tubes 5 in a simple manner.

According to the illustrated example, the second frames 15 respectively have a predefined number of through-openings 152, here two through-openings 152, of fluid communication.

These through openings 152 are here arranged on the longitudinal edges of the second frames 15 and are aligned with each other in the direction of the height of the heat exchange bundle 3.

The through openings 152 open respectively to the inside of a second frame 15.

In addition, in the illustrated example, the through openings 152 are arranged on the same side of a second frame 15 in the longitudinal direction, that is to say here at left or right, complementary to the arrangement of the tubes 21 on the same side of the heat exchange bundle 3, here to the right with reference to the arrangement shown in Figure 1.

The through openings 152 define a fluid inlet 152 to the inner space of the second frame 15 on a longitudinal edge, and a fluid outlet 152 out of the second frame 15 on the opposite longitudinal edge.

More specifically, according to the illustrated example, the second frames 15 have handles 153 which define the through openings 152. The handles 153 of the second frames 15 are made similarly to the handles 134 of the first frames 13 and are aligned with these 134 handles that allow the passage of the second fluid through the heat exchange bundle 3.

By way of illustration, the figures show different embodiments of the handles 153, in particular FIGS. 1 and 6 illustrate a first embodiment of the loops 153 of substantially rounded shape, while FIG. 3 illustrates a second exemplary embodiment. handles 153 whose contour is more rectilinear shape.

Of course, when the loops 134 of the first frames 13 are made according to the first embodiment, the loops 153 of the second frames 15 are made similarly according to the first embodiment.

And when the handles 134 of the first frames 13 are made according to the second embodiment, the handles 153 of the second frames 15 are made similarly according to the second embodiment.

Of course, any other form of the handles 153 may be considered.

Among the two loops 153 of the second frames 15, the opening defined by a first loop is arranged in fluid communication with a first pipe 21 and the opening defined by a second loop is arranged in fluid communication with a second pipe 21.

As said above, the heat exchanger 1 is preferably assembled by brazing. The second frames 15 are intended to be soldered to the first frames 13. In particular, the longitudinal edges of the second frames 15 are intended to be assembled by soldering to the longitudinal edges of the first frames 13 and the lateral edges of the second frames 15 are intended to be assembled by soldering with the arches 133 provided on the edges of the first frames 13.

Furthermore, the second frames 15 may also be shaped to put in fluidic communication two heat exchange tubes 5 received in the same first frame 13.

It is therefore the second frames 15 which allow the circulation in at least two passes of the first fluid in each first frame 13, while ensuring a good mechanical strength of the first frames 13 due to the C0 ₂ under high pressure circulating in the tubes. heat exchange 5.

More specifically, each second frame 15 advantageously has at least one overturning orifice 155 (see FIGS. 3, 6 and 7) which is in fluid communication with both a first and a second fluid communication means 131, here a first and second recesses 131, first frames 13 on either side of the second spacer frame.

Thus, each turning orifice 155 is arranged between two adjacent heat exchange tubes 5 received in a first frame 13 and in fluid communication with these two heat exchange tubes 5.

In this way, the first fluid which opens out of a first heat exchange tube 5 undergoes a reversal in the overturning orifice 155 and then flows to a second heat exchange tube 5.

The two rows of heat exchange tubes 5 arranged in the first frames 13 then communicate at one end via the overturning orifices 155 provided on the second frames 15.

Each overturning orifice 155 is here provided between through-through orifices 151 on at least one lateral edge of each second frame 15, in particular a spacer.

Each turning orifice 155 advantageously has a longitudinal shape extending substantially perpendicular to the general direction the flow of the first fluid in the two heat exchange tubes 5. In this example, each turning orifice 155 has a longitudinal shape extending perpendicularly to the longitudinal edges of the second frame 15, in particular intermediate.

In particular, each turning orifice 155 arranged facing a first receiving frame 13, extends longitudinally on either side of the partition wall 135 of this first receiving frame 13, as is better visible on Figure 7.

By way of example, the turning orifice 155 has a substantially oblong shape.

Furthermore, the turning orifice 155 is dimensioned so as to have a section for the overturning of the first fluid at least equal to the passage section of a heat exchange tube 5.

The design of the spacers, for example in the form of spacer frames 15, with an overturning orifice 155 into which the fluidic communication means 131 respectively associated with one of the heat exchange tubes 5 received in the same first frame 13, allows a simple way to ensure the half-turn or flipping of the first fluid having circulated in a first heat exchange tube 5 to flow to the second heat exchange tube 5 adjacent.

In addition, the overturning orifice 155 shaped and dimensioned as described above allows the second frame 15 to have good strength properties.

Claims

1. Heat exchanger (1), in particular for a motor vehicle, said exchanger (1) comprising:

a heat exchange bundle (3) with a plurality of heat exchange tubes (5) defining circulation channels for a fluid, and

at least one fluid collection box (19),

characterized in that the heat exchange bundle (3) comprises an alternating stack of a plurality of first frames (13) and spacers (15), such as:

each first frame (13) receives at least a first and a second heat exchange tube (5), and comprises:

First means for fluidic communication (131) of the first heat exchange tube (5) with the fluid collection box (19) and

Second means for fluidic communication (131) of the second heat exchange tube (5) with the fluid collection box

(19), and

the spacers (15) furthermore have respectively at least one overturning orifice (155) arranged in fluid communication with both a first fluidic communication means (131) and a second fluidic communication means (131) at least one first frame (13) facing the spacer (155),

in such a way as to allow the fluid emerging from a first heat exchange tube (5) to overturn in the overturning orifice (155) and to flow to a second heat exchange tube (5) adjacent in a first frame (13).

2. Heat exchanger (1) according to the preceding claim, wherein the overturning orifice (155) has a substantially longitudinal shape, preferably substantially oblong.

3. Heat exchanger (1) according to any one of the preceding claims, wherein the spacers (15) are in the form of second frames (15), and wherein the overturning orifice (155) is provided on at least one edge of each second frame (15) extending substantially perpendicular to the general direction of the fluid flow in the circulation channels of the heat exchange tubes (5).

Heat exchanger (1) according to the preceding claim, wherein the second frames (15) have fluid passage guides (151), such as through holes (151) formed on at least one edge of each second frame (15) and communicating with the means for fluid communication (131) of the first frames (13), so as to allow the flow of fluid through the stack.

Heat exchanger (1) according to the preceding claim, wherein the passage guides (151) are arranged in alignment with the fluid communication means (131) of the first frames (13).

Heat exchanger (1) according to any one of the preceding claims, wherein each first frame (13) further has a partition (135) between two heat exchange tubes (5), and wherein the orifice of turning (155) extends on both sides of the partition (135) when a first frame (13) and a spacer (15) are stacked.

Heat exchanger (1) according to the preceding claim, wherein the partition (135) extends along the entire length of the heat exchange tubes (5).

Heat exchanger (1) according to one of claims 6 or 7, wherein the partition (135) of a first receiving frame (13) is formed in one piece with the first receiving frame (13) .

Heat exchanger (1) according to any one of the preceding claims, wherein the fluid able to circulate in the circulation channels of the tubes heat exchanger (5) is a cooling fluid, such as CO ₂ , intended to circulate at high pressure, especially at a pressure greater than 100 bar.

10. Heat exchanger (1) according to any one of the preceding claims, for a heat exchange between a first fluid able to flow in the circulation channels of the heat exchange tubes (5) and a second fluid able to flow between the heat exchange tubes (5), configured for circulation in at least two passes of the first fluid and the second fluid.