EP3394545B1 - Heat exchanger, notably for a motor vehicle - Google Patents

Description

The invention relates to the field of heat exchangers. US 3,334,399 discloses a heat exchanger comprising the characteristics of the preamble of claim 1.

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

Such heat exchangers find particular application in motor vehicles. They can in particular constitute a gas cooler in which the refrigerant 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 too cold temperatures, their autonomy can decrease significantly and if they are subjected to too high temperatures, there is a risk of thermal runaway which can go 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 heat transfer fluid, generally a coolant comprising a mixture of glycol water, which circulates within a heat exchanger in contact with the battery(ies). The coolant can thus provide heat to the battery(ies) to heat them, this heat having been absorbed by the coolant for example during the heat exchange with the CO ₂ circulating in the gas cooler. The coolant can also, if necessary, absorb heat emitted by the battery(ies) in order to cool them and evacuate this heat to one or more other heat exchangers.

Such heat exchangers can also be used like any other gas cooler in an air conditioning circuit.

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

For example, heat exchangers are known comprising a stack of plates allowing the circulation of the first fluid, such as the refrigerant fluid or refrigerant gas, and the second fluid such as the cooling liquid. In order to improve heat exchange, it is known to provide separation partitions on these plates delimiting several circulation passes of one fluid or both fluids. A problem linked to the circulation of a fluid in several passes is to improve the heat exchange while reducing the pressure losses of the fluid. Furthermore, the plate heat exchangers known from the prior art do not make it possible to withstand such high pressures.

We also know from the prior art heat exchangers comprising a stack of tubes connected together 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 in liquid form, can circulate around the tubes in an envelope connected to a water box.

However, such an architecture is complex to produce and presents in particular drawbacks in terms of sealing, in particular in the case of a brazed heat exchanger for which it proves necessary to provide multiple brazing points for several parts of the heat exchanger. In addition, with this architecture, the two fluids generally circulate in cross flow. It is not always possible to provide counter-current circulation or even in several passes of the two fluids, which limits the efficiency of the heat exchanger. It has also been noted that such a heat exchanger does not always have good mechanical strength.

Furthermore, a constant problem with heat exchangers implemented in a motor vehicle lies in the allocation of reduced space, in order to meet the manufacturers' requirements.

The present invention aims to improve the solutions of the state of the art and to at least partially resolve the drawbacks set out above by proposing a simple to produce heat exchanger having better heat exchange performance, this by limiting heat losses. charge.

To this end, the subject of the invention is a heat exchanger, in particular for a motor vehicle, said exchanger comprising a heat exchange bundle defining circulation channels for at least one fluid.

• l'échangeur thermique comprend un nombre prédéfini de cadres définissant respectivement un canal de circulation pour ledit fluide, chaque cadre définissant une largeur interne et une longueur interne, et
• chaque cadre comporte au moins une barrette interne :
  • de plus petite largeur que ledit cadre, et
  • s'étendant longitudinalement à l'intérieur dudit cadre sur une longueur inférieure à la longueur interne dudit cadre,

de manière à définir un trajet en au moins deux passes pour ledit fluide dans ledit cadre. De plus, la largeur de la barrette interne est supérieure ou égale, de préférence strictement supérieure, à l'épaisseur dudit cadre, dans la direction d'empilement desdits cadres.According to the invention,

• the heat exchanger comprises a predefined number of frames respectively defining a circulation channel for said fluid, each frame defining an internal width and an internal length, and
• each frame has at least one internal bar:
  • of smaller width than said frame, and
  • extending longitudinally inside said frame over a length less than the internal length of said frame,

so as to define a path in at least two passes for said fluid in said frame. In addition, the width of the internal bar is greater than or equal to, preferably strictly greater than, the thickness of said frame, in the direction of stacking of said frames.

Such frames allow, in a simple manner, circulation in at least two passes of at least one fluid, for example coolant, in the heat exchanger, thus improving the performance of the heat exchanger.

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, heat exchange tubes can be positioned in our example.

Note that the heat exchange bundle, which comprises a plurality of heat exchange tubes, is distinct from the frames.

• la barrette interne s'étend sur une longueur au moins égale à la moitié de la longueur interne dudit cadre. Les dimensions de la barrette ainsi choisies permettent d'optimiser les performances thermiques tout en limitant les pertes de charge ;
• ledit cadre et la barrette interne sont conformés de manière à vérifier la relation suivante : $0.49<\frac{\mathrm{l}}{L}\le 0.95$
  
  ;
• la longueur interne dudit cadre est comprise dans une plage de l'ordre de 30mm à 500mm ;
• chaque cadre est de forme sensiblement rectangulaire, et la barrette interne s'étend depuis un bord dudit cadre formant un petit côté s'étendant dans le sens de la largeur ;
• ledit cadre comprend un bord sensiblement parallèle à la barrette interne et présentant au moins une entrée de fluide s'étendant sur une longueur d'entrée de fluide, et la barrette interne est agencée à l'intérieur dudit cadre en étant éloignée dudit bord présentant l'entrée de fluide par une distance latérale, telle que la longueur d'entrée de fluide est supérieure ou égale à la distance latérale, selon la relation : L1 ≥ L2 ;
• la barrette interne est agencée sensiblement au centre dudit cadre dans le sens de la largeur dudit cadre ;
• la distance latérale entre la barrette interne et les deux bords opposés dudit cadre parallèles à la barrette interne, est la même de chaque côté de la barrette interne ;
• ledit cadre est dépourvu de barrette sur une longueur restante entre l'extrémité longitudinale libre de la barrette interne et le bord dudit cadre en regard de l'extrémité longitudinale libre de la barrette interne s'étendant sensiblement perpendiculairement à la barrette interne, et la longueur d'extension de la barrette interne est choisie de sorte que la distance latérale est supérieure ou égale à la longueur restante, selon la relation : L2 ≥ L3 = L - l;
• la distance latérale est comprise dans une plage de l'ordre de 15mm à 60mm ;
• l'échangeur thermique comprend au moins une tubulure d'entrée et une tubulure de sortie pour ledit fluide, et lesdits cadres présentent respectivement des ouvertures traversantes de mise en communication fluidique avec les tubulures d'entrée et de sortie, et débouchant respectivement sur l'intérieur dudit cadre, au moins une ouverture traversante définissant une entrée de fluide ;
• lesdits cadres présentent respectivement au moins deux anses délimitant les ouvertures de mise en communication fluidique, et formées sur deux bords opposés dudit cadre s'étendant sensiblement parallèlement à la barrette interne ;
• ledit cadre et chaque ouverture de mise en communication fluidique sont conformés de manière à définir une aire de mise en communication fluidique comprise dans une plage dont :
  • la borne supérieure correspond à trois fois le produit de la longueur d'entrée de fluide avec la longueur restante, et
  • la borne inférieure est le dixième du produit de la longueur d'entrée de fluide avec la longueur restante,
    de manière à vérifier la relation suivante : $$0.1\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3\le \mathrm{<figure-callout\; id="1"\; label="S"\; filenames="imgf0001.png"\; state="\{\{state\}\}">S</figure-callout>}1\le 3\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3$$
    
• l'épaisseur dudit cadre est de l'ordre de 0.5mm à 4mm, de préférence de l'ordre de 2mm, dans la direction d'empilement desdits cadres ;
• chaque cadre comprend des turbulateurs d'écoulement dudit fluide disposés de part et d'autre de la barrette interne ;
• l'épaisseur des turbulateurs est sensiblement égale à l'épaisseur dudit cadre, dans la direction d'empilement desdits cadres.

The heat exchanger may also include one or more of the following characteristics taken alone or in combination:

• the internal bar extends over a length at least equal to half the length internal of said frame. The dimensions of the strip thus chosen make it possible to optimize thermal performance while limiting pressure losses;
• said frame and the internal bar are shaped so as to verify the following relationship: $0.49<\frac{\mathrm{L}}{L}\le 0.95$
  
  ;
• the internal length of said frame is included in a range of the order of 30mm to 500mm;
• each frame is of substantially rectangular shape, and the internal bar extends from an edge of said frame forming a short side extending in the width direction;
• said frame comprises an edge substantially parallel to the internal bar and having at least one fluid inlet extending over a fluid inlet length, and the internal bar is arranged inside said frame being distant from said edge having the fluid entry through a lateral distance, such that the fluid entry length is greater than or equal to the lateral distance, according to the relationship: L1 ≥ L 2;
• the internal bar is arranged substantially in the center of said frame in the direction of the width of said frame;
• the lateral distance between the internal bar and the two opposite edges of said frame parallel to the internal bar, is the same on each side of the internal bar;
• said frame is devoid of bar over a remaining length between the free longitudinal end of the internal bar and the edge of said frame facing the free longitudinal end of the internal bar extending substantially perpendicular to the internal bar, and the length extension of the internal bar is chosen so that the lateral distance is greater than or equal to the remaining length, according to the relationship: L2 ≥ L 3 = L - l ;
• the lateral distance is in a range of the order of 15mm to 60mm;
• the heat exchanger comprises at least one inlet pipe and one outlet pipe for said fluid, and said frames respectively have through openings for fluid communication with the inlet and outlet pipes, and opening respectively onto the interior of said frame, at least one through opening defining a fluid inlet;
• said frames respectively have at least two handles delimiting the openings for fluidic communication, and formed on two opposite edges of said frame extending substantially parallel to the internal bar;
• said frame and each fluidic communication opening are shaped so as to define a fluidic communication area included in a range including:
  • the upper limit corresponds to three times the product of the fluid inlet length with the remaining length, and
  • the lower limit is the tenth of the product of the fluid inlet length with the remaining length,
    in order to verify the following relationship: $$0.1\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3\le \mathrm{<figure-callout\; id="1"\; label="S"\; filenames="imgf0001.png"\; state="\{\{state\}\}">S</figure-callout>}1\le 3\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3$$
    
• the thickness of said frame is of the order of 0.5mm to 4mm, preferably of the order of 2mm, in the direction of stacking of said frames;
• each frame comprises flow turbulators of said fluid arranged on either side of the internal bar;
• the thickness of the turbulators is substantially equal to the thickness of said frame, in the direction of stacking of said frames.

According to another aspect of the invention, the heat exchanger allows heat exchange between at least a first fluid and a second fluid, and comprises an alternating stack of first frames for receiving heat exchange tubes defining first circulation channels for the first fluid, and second frames respectively defining second circulation channels for the second fluid and respectively comprising said at least one internal bar.

The heat exchanger thus comprises a stack of simple elements, namely first frames in which the first fluid circulates, such as a fluid refrigerant, and between which second frames are arranged, the second fluid such as coolant circulating in these second frames.

The superimposed frames make it possible to create the flow path of the first fluid such as a refrigerant fluid, when the frames are assembled, preferably by brazing, and likewise, the superimposed frames make it possible to create the flow path of the second fluid such as coolant in particular on two opposite sides of the heat exchange bundle.

Such an architecture allows a simpler production of the heat exchanger as a whole which has a reduced bulk while having interesting properties in order to best resist high local pressures, in particular due to the circulation of CO ₂ as refrigerant fluid in the first executives.

According to yet another aspect, the heat exchanger is assembled by brazing.

• la figure 1 est une vue en perspective d'un échangeur thermique, et
• la figure 2 est une vue en perspective d'un cadre de l'échangeur thermique de la figure 1.

Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings among which:

• there figure 1 is a perspective view of a heat exchanger, and
• there figure 2 is a perspective view of a heat exchanger frame of the figure 1 .

In these figures, the substantially identical elements bear 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 only apply to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

In this document, the terms upper and lower, or top and bottom, or vertical and horizontal, are designated with reference to the arrangement of the elements on the figures. This arrangement corresponds to the inverted arrangement of the elements in the mounted state in a motor vehicle in particular.

Heat exchanger

In reference to the figure 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 presents at least partially, that is to say on at least certain elements or certain parts, a coating intended to melt to ensure the junction of elements of the heat exchanger during the assembly by brazing.

Such a coating is commonly referred to as “clad” in the field of brazing metal parts, particularly aluminum.

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

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

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

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 allowing the heat exchange between the first fluid and the second fluid.

In the example illustrated, the heat exchange bundle 3 has a shape generally substantially parallelepiped.

The circulation of the first and second fluids advantageously takes place countercurrently in the heat exchange bundle 3.

The introduction and evacuation of the first fluid into the heat exchange bundle 3 or out of the heat exchange bundle 3 is shown schematically by way of example by the arrows F1 _I for introduction and F1 _O for evacuation .

Likewise, the introduction of the second fluid into the heat exchange bundle 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 F2 _I for the introduction and F2 _O for evacuation.

Finally, the heat exchanger 1, and more precisely the heat exchange bundle 3, can be configured for circulation in at least two passes of one of the two fluids, here at least of the second fluid, or even circulation in at least two passes. least two passes of the two fluids.

An example of circulation of the two fluids against the current and in two passes is illustrated schematically by the arrows F1 and F2 on the figure 1 .

More precisely, the heat exchange bundle 3 alternately comprises first circulation channels for the first fluid (not visible in the figures) and second circulation channels 9 for the second fluid (see figure 2 ).

According to a preferred embodiment, the heat exchange bundle 3 comprises a plurality of heat exchange tubes (not visible in the figures) stacked so as to alternately define the first circulation channels for the first fluid in the tubes. heat exchange (not visible in the figures) and the second circulation channels 9 for the second fluid between the heat exchange tubes (not visible in the figures).

The heat exchange tubes can be made by extrusion, for example in the form of flat tubes, advantageous in terms of size.

The first channels or micro-channels (not visible in the figures) then extend substantially longitudinally, in a direction parallel to the direction longitudinal of the heat exchange tubes (not visible in the figures).

The first fluid can follow a circulation in one pass called “I” or rectilinear circulation, but also as a variant a circulation in at least two passes, for example a so-called “U” circulation.

Advantageously, the heat exchange tubes (not visible in the figures) can be received in first frames 13.

Spacers are advantageously arranged between the first frames 13, and define the pitch between the heat exchange tubes (not visible in the figures) for example received in the first frames 13.

According to the invention, the second circulation channels 9 are defined by frames 15, hereinafter called second frames 15.

Furthermore, turbulators (not illustrated) of the flow of the second fluid can advantageously be arranged in the second circulation channels 9 defined by the second frames 15, thus improving the heat exchange of the two fluids.

The turbulators (not shown) can for example have a substantially crenellated shape, forming projections in the second circulation channels 9.

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

A plurality of second frames 15 arranged between two successive first frames 13 form the spacers.

The stacking is done here approximately vertically.

Each first frame 13 is capable of defining at least one first circulation channel for the first fluid, for example each first frame 13 is capable of receiving at least one heat exchange tube, and this assembly forms a stage of the exchange bundle thermal 3.

The first frames 13 can be designated as tube frames.

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

These two sets or stages are repeated as many times as necessary following 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, closure plates 17, 18, in particular at least one lower closure plate 17 and at least one upper closure plate 18, can be arranged on either side of the stack of first frames 13 and second frames 15, so as to close the heat exchange bundle 3.

The closing plates 17, 18 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 collector box 19 for the first fluid arranged in fluid communication with the first circulation channels in the first frames 13.

The collector box 19 is, according to the example illustrated, arranged on an upper closing plate 18 placed at the top of the heat exchange bundle 3.

Of course, according to a variant not illustrated, the collector box 19 can be arranged on the lower closing plate 17 placed at the bottom of the heat exchange bundle 3.

The same collector box 19 can be compartmentalized, so as to define on the one hand the introduction of the first fluid schematized by the arrow F1 _I on the figure 1 and on the other hand the evacuation of the first fluid schematized by the arrow F1 _O on the figure 1 .

The heat exchanger 1 further comprises at least two fluid inlet and outlet pipes 21 allowing the introduction and evacuation of the second fluid.

In this example, the two tubes 21 are arranged on the same upper closure plate 18 as the collector box 19 for the first fluid.

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

According to a variant not illustrated, it is possible to arrange the tubes 21 separately, with one tube 21 on the upper closing plate 18 and the other tubing 21 on the lower closing plate 17.

In particular, the collector box 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 counter-current circulation of the two fluids.

According to the arrangement illustrated on the figure 1 , the collector box 19 is arranged on the left while the pipes 21 are arranged on the right.

Furthermore, preferably, we provide in a complementary manner both a two-pass, so-called “U”-shaped circulation of the first fluid in a first receiving frame 13, and a two-pass, so-called “U”-shaped circulation of the second fluid in a second frame 15.

The heat exchanger 1 is then “U”-shaped double circulation.

First frames called tube frames

Concerning the first frames 13, they can be at least partially made of aluminum.

These first frames 13 can have a thickness of the order of a few millimeters, for example of the order of 1mm.

When they receive heat exchange tubes (not shown in the figures), these first frames 13 can have the same thickness as the heat exchange tubes that they receive.

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. This is the thickness in the stacking direction of the frames 13, 15.

Thus, the heat exchange tubes can be held in the first respective frames 13 before superposition of the different frames.

Each first frame 13 can receive a heat exchange tube or alternatively at least two heat exchange tubes, so that the heat exchange bundle 3 then has at least two rows of heat exchange tubes.

Furthermore, in order to allow circulation in at least two passes of the first fluid, two adjacent heat exchange tubes arranged in a first frame 13 can communicate with each other at one end.

The first frames 13 are for example of generally rectangular shape.

However, according to other embodiments, frames could be provided having a general shape which is not rectangular, for example elliptical, or diamond-shaped.

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

The means of fluidic communication (not visible in the figures) of each first frame 13 are advantageously arranged in fluidic communication with the means of fluidic communication of the other first frames 13 of the heat exchange bundle 3 and with the collector box 19.

These fluidic communication means (not visible in the figures) are for example made in the form of recesses defining through openings for fluidic communication, into which the first circulation channels of the first fluid open, in particular the longitudinal ends, heat exchange tubes received in the first frames 13.

Through openings are advantageously arranged on two opposite edges of the first frames 13. These are for example the lateral edges of the first frames 13 extending in the direction of the width of the heat exchanger 1.

The fluidic communication means provided on the first frames allow, in a simple manner, to collect the first fluid and distribute it for example in the heat exchange tubes maintained in these first frames.

It is no longer necessary to provide collectors on each side of the tubes as in known solutions.

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 example illustrated, the first frames 13 are respectively shaped with at least one handle 134 which, when at least one heat exchange tube is arranged in the first frame 13, makes it possible to define a through orifice allowing the flow 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 heat exchange bundle 3.

As an illustrative example, in the figures there is shown an embodiment of the handles 134 of substantially rounded shape.

Of course, any other shape of the handles 134 can be considered.

The first receiving frames 13 can be made by stamping cutting.

Second frames

In reference to the figure 2 , we now describe the second frames 15 in more detail.

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

The second frames 15 can be made by stamping cutting.

The second frames 15 have a thickness Th 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 this example it is the thickness in the direction of stacking of the frames 13, 15.

The thickness or height of the second frames 15 makes it possible to define the pitch between the first frames 13.

A plurality of second frames 15 called spacers, arranged between two first frames 13 for receiving the heat exchange tubes 5, thus define the pitch between two stages of the heat exchange bundle 3 in which the first fluid circulates.

When the second frames 15 receive turbulators (not shown), the second frames 15 are called turbulator frames or turbulator-carrying frames. The thickness of the turbulators (not shown) can be substantially equal to the thickness Th of a second frame 15.

Advantageously, the second fluid can circulate in at least two passes in each second frame 15.

According to the illustrated embodiment, the second fluid can circulate in two passes, in a so-called “U” circulation, in each second frame 15.

The second frames 15 have two opposite edges 15A, 15B extending perpendicular to the general direction of flow of the second fluid and two other opposite edges 15C, 15D extending parallel to the general direction of the second fluid.

The general direction of flow of the second fluid here means the direction of the branches of the “U” in the case of two-pass circulation of the second fluid.

• deux bords latéraux 15A, 15B, formant des petits côtés, s'étendant dans le sens de la largeur, et
• deux bords longitudinaux 15C, 15D, formant des grands côtés.

In the examples illustrated, the second frames 15 are of generally rectangular shape. The second frames 15 present in this case:

• two side edges 15A, 15B, forming short sides, extending in the width direction, and
• two longitudinal edges 15C, 15D, forming long sides.

The second frames 15 advantageously have a shape similar to and complementary to the shape of the first frames 13.

In particular, the external contours of the first frames 13 and second frames 15 are practically identical so that the alternating stacking of the first frames 13 and second frames 15 forms a block.

According to the illustrated embodiment, the second frames 15 extend over the same length and over the same width as the first frames 13.

As said previously, the heat exchanger 1 is preferably assembled by brazing. In this case, the second frames 15 are intended to be assembled by brazing to the first frames 13.

In particular, the longitudinal edges 15C, 15D of the second frames 15 are intended to be assembled by brazing to the longitudinal edges of the first frames 13 and the lateral edges of the second frames 15 are intended to be assembled by brazing to the lateral edges of the first frames 13.

More particularly, each second frame 15 defines an internal width and an internal length L (see figure 2 ).

By “internal width” is meant the width defined between the internal walls, facing the interior of the second frame 15, of the opposite longitudinal edges 15C and 15D.

By “internal length” is meant the length L defined between the internal walls, facing the inside of the second frame 15, of the opposite side edges 15A and 15B.

Furthermore, the side edges of the second frames 15 can be slightly larger than the side edges of the first frames 13, so that when heat exchange tubes are received in the first frames 13, the ends of these exchange tubes thermal (not shown), rest on the peripheral edge of the side edges of the second frames 15.

The second frames 15 define in this case an internal length L less than the internal length defined by the internal space of the first frames 13.

In other words, the internal length L of a second frame 15 is defined relative to the surface of the second frame 15 which is actually crossed by the second fluid.

In addition, the second frames 15 each comprise at least one bar 150, arranged inside the respective second frame 15 so as to separate two circulation passes for the second fluid. It is therefore an internal strip 150.

In the example illustrated, the bar 150 makes it possible to shape the second circulation channel 9 defined by a second frame 15 substantially "U".

According to the illustrated embodiment, a second frame 15 comprises a single bar 150.

Of course, one could provide a circulation of the second fluid in more than 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 offset and opposite each other.

When the second frames 15 receive turbulators (not shown) for the flow of the second fluid, the turbulators are then advantageously arranged on either side of the or each internal bar 150.

The or each bar 150 extends longitudinally inside a second frame 15.

The or each bar 150 therefore extends in this example substantially parallel to the longitudinal edges 15C and 15D of the second frame 15.

The bar 150 does not extend over the entire internal length L of the second frame 15. In other words, the bar 150 extends from a side edge 15A of a second frame 15 towards the opposite side edge 15B but without reaching this opposite side edge 15B.

The internal bar 150 therefore extends longitudinally from a side edge 15A of a second frame 15 towards the opposite side edge 15B but without reaching this opposite side edge 15B.

The bar 150 is therefore integral with a side edge 15A of a second frame 15 and projects with its free end towards the internal space of the second frame 15 in the direction of the opposite side edge 15B, leaving a space.

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

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

The width W of the internal bar 150 can be greater than or equal to, preferably strictly greater than the thickness Th of the second frame 15.

We thus define on each side of the bar 150, the entry and exit of the flow path for the second fluid. The strip 150 can also be described as a tab.

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 precisely, the bar 150 is arranged substantially in the center of a second frame 15 in the direction of the width 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 internal bar 150 extends over a length l at least equal to half the internal length L of a second frame 15.

• l = longueur d'extension de la barrette interne 150, et
• L = longueur interne du deuxième cadre 15.

In particular, each second frame 15 and the internal bar 150 of this second given frame 15 can be shaped so as to verify the following relationship (a): $$0.49<\frac{\mathrm{L}}{L}\le 0.95\mathrm{with}$$

• l = extension length of the internal bar 150, and
• L = internal length of the second frame 15.

Preferably, the upper limit is also defined by a strict relation, so that the second frame 15 and its internal bar 150 verify the following relation (a'): $$0.49<\frac{\mathrm{L}}{L}<0.95.$$

According to an exemplary embodiment, each second frame 15 may have an internal length L within a range of the order of 30mm to 500mm.

Furthermore, in addition to the first receiving frames 13, the second frames 15, in particular the second intermediate frames 15 arranged between two first frames 13, present guides for the passage of the first fluid allowing its flow in the stack of the first frames 13 and second frames 15.

The guides, for example made in the form of through passage orifices, are for example arranged in the alignment of the means for fluidic communication of the first reception frames 13.

In addition, the second frames 15 respectively present means 152 for placing the second circulation channels 9 in fluid communication with each other on the one hand and with the pipes 21 for the second fluid on the other hand.

The fluid communication means 152 provided on the second frames 15 allow, in a simple manner, to collect the second fluid and distribute it in the second frames 15.

According to the example illustrated on the figure 2 , each second frame 15 has a predefined number of through openings 152 for fluidic communication, for example here two through openings 152 for fluidic communication. These through openings 152 are here arranged on the longitudinal edges 15C and 15D 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 onto the inside of a second frame 15.

Furthermore, in the example illustrated on the figures 1 and 2 , the through openings 152 are arranged on the same side of a second frame 15 in the longitudinal direction, that is to say here on the right or on the left, in a manner complementary to the arrangement of the tubes 21 on the same side of the heat exchange bundle 3.

The through openings 152 make it possible to define a fluid inlet 152 towards the interior space of the second frame 15, which is in the example illustrated, provided on a longitudinal edge 15C, and a fluid outlet 152 outside the second frame 15, which is in the example illustrated, arranged on the opposite longitudinal edge 15D.

More precisely, according to the example illustrated, the second frames 15 have handles 153 which make it possible to delimit the through openings 152.

The handles 153 of the second frames 15 are made in a similar manner to the handles 134 of the first frames 13 and are aligned with these handles 134 which allow the passage of the second fluid through the heat exchange bundle 3.

For illustration purposes, the figures show an example of producing the handles 153 of substantially rounded shape.

The shape of the handles 153 of the second frames 15 is complementary to the shape of the handles 134 of the first frames 13.

Of course any other shape of the handles 153 can be considered.

Among the two handles 153 of the second frames 15, the opening delimited by a first handle 153 is arranged in fluid communication with a first tube 21 and the opening delimited by a second handle 153 is arranged in fluid communication with a second tube 21.

In addition, according to the embodiment illustrated on the figure 2 , the fluid inlet 152 extends over a maximum fluid inlet length L1.

This maximum fluid inlet length L1 is, according to the particular embodiment illustrated, defined by the maximum length of the loop 153, at the level of the start of its formation on the second frame 15.

Furthermore, the internal bar 150 is arranged inside a second frame 15 so that the bar 150 is spaced by a lateral distance L2, here in the width direction, from the longitudinal edge 15C of the second frame 15 presenting the fluid inlet 152.

In particular in this example, the central bar 150 is spaced by the same lateral distance L2 from each longitudinal edge 15C, 15D of the second frame 15.

This lateral distance L2 is considered in relation to the part of the edge, here the longitudinal edge 15C or 15D, which extends parallel to the bar 150, and not in relation to the loop 153 formed on the side of the longitudinal edge 15C or 15D.

avec

• L1 = longueur d'entrée de fluide maximale et
• L2 = distance latérale entre la barrette et le bord longitudinal du cadre.

Advantageously, the fluid inlet length L1 is greater than or equal to the lateral distance L2 according to relation (b): $$\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\ge \mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0002.png"\; state="\{\{state\}\}">L</figure-callout>}2$$

with

• L 1 = maximum fluid inlet length and
• L 2 = lateral distance between the bar and the longitudinal edge of the frame.

Preferably, the fluid inlet length L1 is strictly greater than the lateral distance L2 according to the relation (b'): $$\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1>\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0002.png"\; state="\{\{state\}\}">L</figure-callout>}2$$

• entre l'extrémité longitudinale libre de la barrette interne 150 et
• le bord, ici le bord latéral du 15B, du deuxième cadre 15 en regard de l'extrémité de la barrette interne 150 s'étendant sensiblement perpendiculairement à la barrette interne 150, autrement dit la longueur restante L3 dépourvue de barrette 150, selon la relation : $$\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0002.png"\; state="\{\{state\}\}">L</figure-callout>}2\ge \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3=L-l$$
  

avec

• L3 = longueur restante dépourvue de barrette interne 150,
• l = longueur d'extension de la barrette interne 150, et
• L = longueur interne du deuxième cadre 15.

In addition, the lateral distance L2 between the internal bar 150 and the edge, here the longitudinal edge 15C or 15D, of a second frame 15, extending parallel to the internal bar 150, is greater than or equal to the remaining length L3 of the second frame 15:

• between the free longitudinal end of the internal bar 150 and
• the edge, here the lateral edge of 15B, of the second frame 15 facing the end of the internal bar 150 extending substantially perpendicular to the internal bar 150, in other words the remaining length L3 devoid of bar 150, according to the relationship : $$\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0002.png"\; state="\{\{state\}\}">L</figure-callout>}2\ge \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3=L-L$$
  

with

• L3 = remaining length without internal bar 150,
• l = extension length of the internal bar 150, and
• L = internal length of the second frame 15.

Preferably, the lateral distance L2 and the remaining length L3 verify a strict relationship (c'): $$\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0002.png"\; state="\{\{state\}\}">L</figure-callout>}2>\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3=L-L.$$

As a non-limiting example, the lateral distance L2 is included in a range of the order of 15mm to 60mm.

Furthermore, each through opening 152 defines a fluidic communication area S1.

• une borne supérieure correspondant à trois fois le produit de la longueur d'entrée de fluide L1 avec la longueur restante L3, et
• une borne inférieure correspondant au dixième du produit de la longueur d'entrée de fluide L1 avec la longueur restante L3.

According to a particular embodiment, each through opening 152 is shaped so that the fluidic communication area S1 is included in a range having:

• an upper limit corresponding to three times the product of the fluid inlet length L1 with the remaining length L3, and
• a lower limit corresponding to one tenth of the product of the fluid inlet length L1 with the remaining length L3.

avec

• S1 = aire de mise en communication fluidique.
• L1 = longueur d'entrée de fluide maximale et
• L3 = longueur restante dépourvue de barrette interne 150.

In other words, each through opening 152 is shaped so that the fluidic communication area S1 verifies the following relation (d): $$0.1\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3\le \mathrm{<figure-callout\; id="1"\; label="S"\; filenames="imgf0001.png"\; state="\{\{state\}\}">S</figure-callout>}1\le 3\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3$$

with

• S 1 = fluidic communication area.
• L 1 = maximum fluid inlet length and
• L 3 = remaining length without internal bar 150.

Preferably, each through opening 152 is shaped so that the fluidic communication area S1 verifies a strict relationship: $$0.1\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3<\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="imgf0001.png"\; state="\{\{state\}\}">S</figure-callout>}1<3\times \mathrm{<figure-callout\; id="1"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}1\times \mathrm{<figure-callout\; id="3"\; label="L"\; filenames="imgf0001.png"\; state="\{\{state\}\}">L</figure-callout>}3.$$

avec

• S2 = aire d'entréede fluide,
• L1 = longueur d'entrée de fluide maximale et
• Th = épaisseur du deuxième cadre 15 dans la direction d'empilement.

The through openings 152 further define respectively a fluid inlet area S2 which is therefore equal to the product of the maximum fluid inlet length L1 by the thickness Th or height of the second frame 15, according to relation (e) next : $$\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="imgf0002.png"\; state="\{\{state\}\}">S</figure-callout>}2=L1\times \mathit{Th}.$$

with

• S 2 = fluid entry area,
• L 1 = maximum fluid inlet length and
• Th = thickness of the second frame 15 in the stacking direction.

avec

• S3 = aire d'écart latéral.
• L2 = distance latérale entre la barrette et le bord longitudinal du cadre,
• Th = épaisseur du deuxième cadre 15 dans la direction d'empilement.

Similarly, the second frame 15 defines a lateral gap area S3 between the internal bar 150 and a longitudinal edge 15C of the second frame 15 which is therefore equal to the product of the lateral distance L2 by the thickness Th or height of the second frame 15, according to the following relation (f): $$\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="imgf0001.png"\; state="\{\{state\}\}">S</figure-callout>}3=L2\times \mathit{Th}.$$

with

• S 3 = lateral deviation area.
• L 2 = lateral distance between the bar and the longitudinal edge of the frame,
• Th = thickness of the second frame 15 in the stacking direction.

avec

• S4 = aire restante,
• l = longueur d'extension de la barrette interne 150, et
• L = longueur interne du deuxième cadre 15.

Finally, the second frame 15 defines a remaining area S4 equal to the product of the remaining length L3 by the thickness Th of the second frame 15, according to the following relation (g): $$\mathrm{<figure-callout\; id="4"\; label="S"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">S</figure-callout>}4=L3\times \mathit{Th}=\left(L-L\right)\times \mathit{Th}.$$

with

• S 4 = remaining area,
• l = extension length of the internal bar 150, and
• L = internal length of the second frame 15.

Thus the internal bar 150 as described above, defining several circulation passes for the second fluid, for example the cooling liquid, in a second frame 15 has dimensions advantageously chosen to optimize the thermal efficiency of the heat exchanger 1 while limiting coolant pressure losses.

Claims (12)

1. Heat exchanger (1), notably for a motor vehicle, said exchanger (1) comprising a heat exchange core bundle (3) defining circulation channels (9) for at least one fluid, such that:

   - the heat exchanger (1) comprises a predefined number of frames (15) respectively defining a circulation channel for said fluid, each frame (15) defining an internal width and an internal length (L) and that

   - each frame (15) comprises at least one internal strip (150) of smaller width (W) than said internal width of said frame (15), and extending longitudinally inside said frame (15) over a length (1) less than the internal length (L) of said frame (15) so as to define an at least two-pass path for said fluid in said frame (15), and characterized in that

   - the width (W) of the internal strip (150) is greater than or equal to, preferably strictly greater than, the thickness (Th) of said frame (15) in the direction of stacking of said frames (15) .
2. Heat exchanger (1) according to the preceding claim, wherein the internal strip (150) extends over a length (1) at least equal to half of the internal length (L) of said frame (15).
3. Heat exchanger (1) according to the preceding claim, wherein said frame (15) and the internal strip (150) are configured in such a way as to satisfy the following relationship: $$0.49<\frac{\mathrm{l}}{L}\le 0.95.$$

   
4. Heat exchanger (1) according to one of the preceding claims, wherein the internal length (L) of said frame (15) is comprised in a range of the order of 30 mm to 500 mm.
5. Heat exchanger (1) according to any one of the preceding claims, wherein:

   - said frame (15) comprises an edge substantially parallel to the internal strip (150) and having at least one fluid inlet (152) extending over a fluid inlet length (L1), and wherein

   - the internal strip (150) is arranged inside said frame (15) distant from said edge having the fluid inlet (152) by a lateral distance (L2) such that the fluid inlet length (L1) is greater than or equal to the lateral distance (L2), according to the relationship: L1 ≥ L2.
6. Heat exchanger (1) according to the preceding claim, wherein:

   - said frame (15) is devoid of strip (150) over a remaining length (L3) between the free longitudinal end of the internal strip (150) and the edge of said frame (15) facing the free longitudinal end of the internal strip (150) extending substantially perpendicular to the internal strip (150), and wherein

   - the length (l) over which the internal strip (150) extends is chosen so that the lateral distance (L2) is greater than or equal to the remaining length (L3) according to the relationship: L2 ≥ L3 = L-l.
7. Heat exchanger (1) according to one of Claims 5 or 6, wherein the lateral distance (L2) is comprised in a range of the order of 15 mm to 60 mm.
8. Heat exchanger (1) according to any one of Claims 5 to 7, comprising at least one inlet nozzle and one outlet nozzle (21) for said fluid, and wherein said frames (15) respectively have through-openings (152) providing fluidic communication with the inlet and outlet nozzles (21) and respectively opening onto the inside of said frame (15), at least one through-opening (152) defining a fluid inlet.
9. Heat exchanger (1) according to the preceding claim, wherein said frames (15) respectively have at least two bows (153) defining the fluidic-communication openings (152) and formed on two opposite edges (15C, 15D) of said frame (15) extending substantially parallel to the internal strip (150).
10. Heat exchanger (1) according to Claims 5 and 6 considered in combination with any one of the preceding claims, wherein said frame (15) and each fluidic-communication opening (152) are configured in such a way as to define a fluidic-communication area (S1) comprised within a range of which:

    - the upper limit corresponds to three times the product of the fluid inlet length (L1) times the remaining length (L3), and

    - the lower limit is one tenth of the product of the fluid inlet length (L1) times the remaining length (L3),

    so as to satisfy the following relationship: $$0.1\times L1\times L3\le S1\le 3\times L1\times L3$$

    
11. Heat exchanger (1) according to any one of the preceding claims, wherein the thickness (Th) of said frame (15) is of the order of 0.5 mm to 4 mm, preferably of the order of 2 mm, in the direction of stacking of said frames (15).
12. Heat exchanger (1) for exchange of heat between at least a first fluid and a second fluid according to any one of the preceding claims, comprising an alternating stack of:

    - first frames (13) receiving heat-exchange tubes defining first circulation channels for the first fluid, and

    - second frames (15) respectively defining second circulation channels for the second fluid and respectively comprising said at least one internal strip (150).

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