CN111565861A

CN111565861A - Tube for heat exchanger with turbulator

Info

Publication number: CN111565861A
Application number: CN201880048225.0A
Authority: CN
Inventors: C.德沃克斯; P.勒布莱; M.里斯纳; M.卡帕罗斯; K.阿佐兹; X.马查迪尔; K.加昂
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2017-07-31
Filing date: 2018-07-31
Publication date: 2020-08-21
Also published as: WO2019025719A1; JP2020529573A; EP3645184A1

Abstract

A tube (2) for a heat exchanger, comprising at least one perturbation device (4) for perturbing the flow of a fluid able to flow in the tube, the perturbation device (4) comprising a local depression of the wall of the tube towards the inside of the tube (42) and having the shape of a chevron (43), the chevron (43) comprising at least a first branch (44) and a second branch (46) extending from a point (48) towards a free end (440, 460).

Description

Tube for heat exchanger with turbulator

The present invention relates to the field of heat exchangers, particularly intended to equip an air-conditioning circuit of a motor vehicle or to cool the engine of a vehicle.

The heat exchanger, especially equipping the air conditioning circuit of a vehicle, is arranged to allow two different fluids to flow adjacently in two separate spaces, so as to exchange heat between the fluids without mixing them. One type of heat exchanger used in particular in the field of motor vehicles is the tubular heat exchanger, which is constituted by a stack of tubes brazed together and arranged so as to define a space for the flow of fluid.

In a heat exchanger and its attached thermodynamic circuit, a fluid dissipates or absorbs thermal energy while flowing. The efficiency of the heat exchanger and thermodynamic circuit is primarily dependent on the exchange of heat between the fluids passing through them. Therefore, there is a need for a heat exchanger design in which the heat exchange between the fluids flowing inside is optimized. For this purpose, it is possible to envisage the mixing of each fluid in the space in which the fluid flows, with the aim of increasing the heat exchange between the fluids, and it is known to equip the heat exchanger with means for disturbing the fluid flow. It will be appreciated that to increase the mixing of the fluids, the number of perturbation means may be increased and therefore they may be positioned close to each other. However, although this solution does help to improve the amount of mixing and heat exchange, the problem of optimizing the heat exchange does not provide a satisfactory answer, since increasing the number of perturbing means leads to significant pressure losses, thus limiting the flow of fluid and therefore the efficiency of the heat exchanger.

The object of the present invention is therefore to overcome the above mentioned drawbacks by devising a tube for a heat exchanger arranged to improve the heat exchange between the fluids passing through the heat exchanger, while in particular limiting the pressure losses experienced by these fluids, which, moreover, is configured to be manufactured by simple machining operations and corresponding tools having a simple shape and therefore cheap.

In this case, the invention therefore relates to a tube for a heat exchanger, comprising at least one perturbation device for perturbing the flow of a fluid able to flow in the tube, the perturbation device comprising a local recess in the wall of the tube towards the inside of the tube and having the shape of a chevron, the chevron comprising at least a first branch and a second branch running from a tip towards a free end.

According to a first embodiment of the invention, the tube defines a flow channel for a fluid capable of flowing in the tube mainly in a first direction, and comprises a plurality of perturbation means for perturbing the flow of the fluid along the flow channel. The perturbation means comprise respectively local depressions in the wall of the tube in a chevron shape towards the inside of the tube. These perturbation means are arranged along the fluid flow channel such that the cross-sectional strip of the tube comprises only the perturbation means, the longitudinal dimension of the cross-sectional strip being equal to the longitudinal dimension of the perturbation means and including the entire perturbation means. This arrangement helps to improve the mixing phenomenon, which increases the heat exchange between the fluids, while providing a good compromise between heat exchange and pressure loss, thereby improving the performance and efficiency of the heat exchanger.

The tube according to this first embodiment of the invention advantageously comprises at least any one of the following features, used alone or in combination:

the section of the pipe considered is the cross section of the pipe, i.e. considered according to a plane perpendicular to the direction of flow of the fluid along the pipe;

the chevron forming the perturbation device comprises at least two branches extending from the tip, the branches being defined by a length comprised between 1.55 and 30 mm; the length is measured from a first end of a branch to a second end of the same branch, the branch connecting another branch to form a tip;

the length of the first branch and the second branch of the chevron is the same;

the length of the branches of the chevron is the same for all the perturbing means;

the branches of the chevron forming the perturbation device are arranged at an angle of development of between 20 ° and 160 ° with respect to the flow direction of the fluid;

the two branches forming the chevron of the perturbing means are arranged at the same angle with respect to the flow direction of the fluid;

the branches forming the chevrons of the perturbation device are all arranged at the same angle with respect to the flow direction of the fluid;

the angle at which the branches of the perturbation means of the tube are arranged with respect to the flow direction of the fluid gradually decreases between the upstream end and the downstream end; the upstream and downstream ends of the tube are defined relative to the direction of flow of the fluid inside the tube; this reduction may be constant, the angular difference between two consecutive chevrons being equal, irrespective of the consecutive chevrons in question, or it may be progressive, the reduction being greater towards one or the other end of the tube;

the perturbation means is defined by a height of between 0.1 and 0.5 mm, the height being measured in a direction perpendicular to the wall of the tube between the inner face of the wall of the tube from which the perturbation means extends and the apex of the perturbation means; advantageously, the height of the perturbation means is between 0.1 and 0.3 mm; this height range helps to increase the disturbance of the fluid through the tube according to the invention, while limiting the increase in pressure loss associated with the disturbance of the fluid flow;

the heights of the chevrons forming the perturbation device are all the same; alternatively, the height of the perturbation means increases gradually between the upstream end of the tube and the downstream end of the tube opposite to the upstream end of the tube; this increase may be constant, the difference in height between two consecutive chevrons being equal, irrespective of the consecutive chevrons in question, or it may be gradual, the increase being greater towards one end or the other of the tube;

the perturbation means are defined by a thickness comprised between 0.5 and 5 mm; the thickness is measured between a plane passing through the middle of the branches at the apex of the perturbation means and a parallel plane passing through the junction edge where the perturbation means meets the respective wall of the tube;

the chevrons of all the perturbation devices have the same thickness;

-the perturbation means are arranged on at least one wall of the tube;

the perturbation means are arranged on two opposite walls of the tube;

the perturbation devices are arranged alternately on the top wall and on the opposite bottom wall, all the perturbation devices being arranged inside the channel defined between these two walls;

-the chevrons forming the perturbation device arranged on the first wall are oriented in the opposite direction to the chevrons forming the perturbation device on the second wall;

the perturbation means are arranged in at least two lines in the longitudinal direction of the tube, the interval between two consecutive lines being between 1.5 and 30 mm; the spacing corresponds to the distance between two adjacent lines of perturbation means arranged on the same wall of the tube; the spacing between two adjacent lines is measured between the tip of the chevron of the perturbation device forming the first line and the tip of the chevron of the perturbation device forming the second line; advantageously, the interline distance is between 3 and 5 mm;

the spacing between two lines of the perturbation means is the same along the whole tube, more specifically the spacing between two adjacent lines is constant from the upstream end of the tube to the downstream end of the tube;

the spacing between all lines is the same, i.e. the spacing between two adjacent lines is the same regardless of the adjacent line in question;

-the perturbation means of the at least one first line are arranged with a longitudinal offset with respect to the perturbation means of the at least one second line;

two successive perturbation devices of the same line are spaced apart at a distance of between 1.5 and 30 mm; the spacing is measured between the tip of the chevron of a first perturbation device and the tip of the chevron of a second perturbation device adjacent to the first perturbation device. Advantageously, the spacing between two perturbation devices arranged consecutively on the same line is between 5 and 10 mm;

the pitch between the chevrons of the same line is the same for each series of chevrons of the same line;

the spacing between the chevrons increases progressively between the upstream end of the tube and the downstream end of the tube;

the perturbation device is integral with the tube carrying it; in other words, the tube and the perturbation device are made of the same piece of material and one cannot be separated from the other without damaging the tube;

the perturbation device is manufactured by drawing, stamping or metal additive manufacturing;

the tube comprises an intermediate wall which divides the inner conduit defined inside the tube into two sub-channels; a chevron forming a turbulator is disposed on each sub-passage; in each sub-channel, the chevrons are symmetrically arranged with respect to the intermediate wall.

According to a second embodiment of the invention, the tube is configured so that at least one geometrical parameter of the chevron shape has a value varying between the tip and each free end of the branch.

This arrangement helps to improve the mixing phenomenon, which increases the heat exchange between the fluids, while providing a good compromise between heat exchange and pressure loss, thereby improving the performance and efficiency of the heat exchanger.

The tube according to this second embodiment of the invention advantageously comprises at least any one of the following features, used alone or in combination:

-the variable geometric parameter is the width of each branch, the value of the width of each branch at the tip being greater than the value of the width of each free end of the branch;

the variable geometric parameter is the angle formed between the branches of the chevron, the value of the angle at the tip being smaller than the value of the angle at the free ends of the branches;

-the variable geometric parameter is the height of the chevron, the value of the height at the tip being greater than the value of the height of each free end of the branch;

-the height is measured in a direction perpendicular to the wall of the pipe between the inner face of the wall of the pipe from which the perturbation device extends and the apex of the perturbation device; the apex of the perturbation means is the point of the portion in question which is furthest from the wall of the tube from which the perturbation means extends; thus, the height of the tip of the perturbation device is measured in a direction perpendicular to the wall of the tube between the inner face of the wall of the tube and the apex of the chevron-shaped tip of the perturbation device; similarly, the height of the free ends of the branches of the perturbation means is measured between the inner face of the wall of the tube and the vertex of the free end of the branch in question, in a direction perpendicular to the wall of the tube;

-the chevrons are symmetrical; more specifically, the chevrons are symmetrical with respect to a plane perpendicular to the wall from which they originate, which passes through the tip and is parallel to the direction of flow of the fluid inside the tube;

the free ends of the branches of the perturbation means are laterally aligned; in other words, the free ends of the branches of the perturbation means lie on a line perpendicular to the flow direction of the fluid; in this arrangement, the fluid flow impacting the chevron simultaneously impacts the two free ends of the branches of the same perturbation device;

-the value of the height of the tip is equal or substantially equal to twice the value of the height of the free end of the branch;

alternatively, the value of the height of the tip is equal or substantially equal to half the value of the height of the free ends of the branches, the value of the width of each branch at the tip then being equal or substantially equal to twice the value of the width of the free end of the branch;

-the value of the height of the tip is equal or substantially equal to the sum of the values of the heights of each free end of the branch;

in the above and in the following, "substantially equal" means here that the value of the height of the tip may not be twice the value of the height of the free end of the branch, but within a range around the value representing twice the height of the free end of the branch, up to within 3%; providing such differences, especially taking into account manufacturing tolerances of the tube or one of its elements;

the transition between the height of the tip and the different heights of the free ends of the branches is gradual, i.e. the transition from the tip to the free ends of the branches forms a regular slope;

the tube comprises a plurality of perturbation means for which the value of the height of the tip is greater than the value of the height of each free end of the branch;

-the perturbation devices are arranged in series between a first longitudinal end of the tube and a second longitudinal end of the tube, at least one of the height values increasing from one device to the next in said series;

-in the direction of flow of the fluid inside the tube, the first longitudinal end of the tube is the upstream end of the tube and the second longitudinal end of the tube is the downstream end of the tube;

-the perturbation means are arranged in series between the first longitudinal end of the tube and the second longitudinal end of the tube, the value of the height of the tip and of each free end of the branch increasing from one means in said series to the next;

the first perturbation device is arranged in a first direction, the second perturbation device is arranged in a second direction opposite to the first direction, and the perturbation devices are defined by a front surface, which is the surface of the perturbation device that is first exposed to the fluid flowing inside the tube, the front surface of the first perturbation device being equal to the front surface of the second perturbation device;

the front surface of the perturbation device increases between the first longitudinal end of the tube and the second longitudinal end of the tube;

the height of the tip has a value between 0.1 and 0.5 mm. Preferably, the height of the tip has a value between 0.3 and 0.5 mm and the free end of the branch has a value between 0.15 and 0.25 mm;

-the branches are defined by a length between 1.55 and 30 mm; the length is measured from a first end of a branch to a second end of the same branch, the branch connecting another branch to form a tip;

the chevrons of all the perturbation devices have the same thickness;

-the perturbation means are arranged on at least one wall of the tube;

the perturbation means are arranged on two opposite walls of the tube;

two successive perturbation devices of the same line are spaced apart at a distance of between 1.5 and 30 mm; the spacing is measured between the tip of the chevron of a first perturbation device and the tip of the chevron of a second perturbation device adjacent to the first perturbation device; advantageously, the spacing between two perturbation devices arranged consecutively on the same line is between 5 and 10 mm;

According to a third embodiment of the invention, the at least one perturbation device of the tube is formed by a plurality of local depressions in the wall of the tube towards the inside of the tube, said local depressions being arranged in a herringbone shape with respect to each other.

The chevron arrangement helps to improve the mixing phenomenon, thereby increasing the heat exchange between the fluids, while providing a good compromise between heat exchange and pressure loss, thereby improving the performance and efficiency of the heat exchanger. Moreover, obtaining the chevron of such shape by a plurality of local depressions makes it possible to manufacture complex shapes similar to a chevron by a plurality of local depressions of the basic shape, simplifying the design of the required tools and thus reducing the cost of the perturbation device to obtain these chevron shapes on the tube.

The tube according to this third embodiment of the invention advantageously comprises at least any one of the following features, used alone or in combination:

the chevron comprises at least one tip, two branches joined at one end to form the tip and having a free end opposite the tip; depending on the orientation of the chevrons in the pipe, the tip and the free end may form one or more leading and trailing edges between which the branch-formed segments form a connection;

-making a first local recess to form the tip and a second local recess to form one of the free ends of the two branches, respectively;

-the third local depression is arranged between the first and second local depressions to form a branch;

-each local depression comprises an apex and a joining edge at which it meets the wall of the tube, the local depression comprising a flared connecting portion between the joining edge and the apex, the segments being made by overlapping of the flared connecting portions;

-the joint edge is in the wall plane of the tube making the local depression; more specifically, the joining edge of each local recess lies in the plane of the inner face of the wall of the tube, i.e. the face turned away from the fluid flow channel provided inside the tube;

the herringbone profile is more particularly made by arranging in series locally recessed flared connection portions arranged in succession on the wall;

the local recesses are arranged in series such that the flared connecting portion of one local recess overlaps with the flared connecting portion of an adjacent local recess in the series; the profile of the chevrons and in particular of the segments thus show continuity, allowing an efficient channeling of the fluid from the leading edge to the trailing edge;

-at least third partial recesses are manufactured close to each other such that the flared connecting portion of one third partial recess overlaps the flared connecting portion of an adjacent third partial recess;

the flared connection portions have the same shape from one local recess to the next, in particular for the same series of local recesses forming a chevron;

as a variant, for a perturbation device having the shape of a chevron with two branches connected at the tip, the pattern for making the local depressions associated with the tip of the chevron and/or the pattern for making the local depressions associated with the free ends of the branches of the chevron may be different from the pattern reused, to form a segment connecting the tip to the free end;

the perturbation means are made of a plurality of elementary patterns, each elementary pattern allowing to make a local depression; the basic pattern of local depressions used to make the perturbation devices may all be the same; as a variant, the perturbation means can be obtained by a combination of basic patterns; this may mean using a specific basic pattern of local depressions corresponding to the leading edge, a specific basic pattern of local depressions corresponding to the trailing edge and a specific basic pattern of local depressions corresponding to the segments;

the angle at which the branches of the perturbation means of the tube are arranged with respect to the flow direction of the fluid gradually decreases between the upstream end and the downstream end; the upstream and downstream ends of the tube are determined relative to the direction of flow of the fluid inside the tube; this reduction may be constant, the angular difference between two consecutive chevrons being equal, irrespective of the consecutive chevrons in question, or it may be progressive, the reduction being greater towards one or the other end of the tube;

the chevrons of all the perturbation devices have the same thickness;

-the perturbation means are arranged on at least one wall of the tube;

the perturbation means are arranged on two opposite walls of the tube;

the perturbation means are arranged in at least two lines in the longitudinal direction of the tube, the interval between two consecutive lines being between 1.5 and 30 mm; the spacing corresponds to the distance between two adjacent lines of perturbation means arranged on the same wall of the tube; the spacing between two adjacent lines is measured between the tip of the chevron of the perturbation device forming the first line and the tip of the chevron of the perturbation device forming the second line. Advantageously, the interline distance is between 3 and 5 mm;

the perturbation device formed by a plurality of local recesses is integral with the tube carrying it; in other words, the tube and the perturbation device are made of the same piece of material and one cannot be separated from the other without damaging the tube;

The invention also relates to a heat exchanger comprising a plurality of tubes, at least one of which is a tube as described above, the tubes defining internally, on the one hand, a flow circuit for the fluid, which is disturbed by the presence of said chevrons forming a means of disturbance as the fluid passes through, and, on the other hand, the tubes defining between them a flow circuit for the air. The invention finally relates to the use of the heat exchanger as an air cooler.

The invention also relates to a method for manufacturing a tube for a heat exchanger as previously described, comprising performing a plurality of steps of pressing at least one wall of the tube, at least one first set of local depressions resulting from the pressing steps forming the chevrons. The pressing step may be performed continuously or simultaneously, and in particular continuously when the local depressions are configured to overlap to form a continuity of formation of the herringbone.

Other features, details and advantages of the invention will become more apparent upon reading the following description by way of example and with reference to the accompanying drawings, in which:

figure 1 is a schematic front view of a heat exchanger made up of a plurality of tubes according to the invention,

figures 2a and 2b are perspective views of a tube according to a first and a second embodiment of the invention,

figure 3 is a cross-sectional view of a tube according to the invention, viewed in a plane perpendicular to the longitudinal direction of the tube,

figures 4a and 4b are top views of a perturbation device formed on a tube according to a second and third embodiment of the present invention,

FIG. 5 is a schematic side view of the perturbation device of FIG. 4a, shown in a slightly perspective manner, so as to also show the opposite branches of the chevron forming the perturbation device;

FIG. 6 is a perspective top view of a tube according to the invention, the bottom wall of the tube and the perturbation means formed therein and the intermediate wall arranged between the bottom wall and the top wall being shown transparently in thin lines,

FIG. 7 is a top view of the inner face of the tube, showing a variant of the arrangement of the perturbation devices on one face of the tube,

FIG. 8 is a perspective top view of a tube according to a third embodiment of the invention, showing a plurality of perturbation means formed on the top wall of the tube,

figure 9 is a detailed top view of the perturbation device formed on the tube of figure 8,

FIG. 10 is a schematic top view of a perturbation device according to an aspect of the present invention, showing the theoretical positions of the local depressions to be made with respect to each other in order to form the chevrons of the perturbation device,

fig. 11 to 13 are embodiments of perturbation devices made of a plurality of local recesses according to the invention, wherein the local recesses have the same circular shape (fig. 11), the same rectangular shape (fig. 12) and different shapes (fig. 13).

It should be noted at the outset that the drawings illustrate the invention in detail for the purpose of practicing the invention, and that they can naturally be used to better define the invention, if desired.

In the following description, the terms "longitudinal", "vertical" or "transverse", "top", "bottom", "front" and "rear" refer to the orientation of the heat exchanger according to the invention. The longitudinal direction corresponds to the main axis of the heat exchanger, along which the largest dimension extends. The vertical direction corresponds to a stacking direction of tubes constituting the heat exchanger, and the lateral direction is a direction perpendicular to the other two directions. The longitudinal, transverse and vertical directions can also be considered as an L, V, T trihedron as shown in the figures.

The terms "upstream" and "downstream" should be considered relative to the direction of flow of the fluid flowing inside the tube of the present invention.

Fig. 1 shows a heat exchanger 1 according to the invention, which is configured to equip the front end of a vehicle, in particular a motor vehicle, and in particular allows heat to be exchanged between two fluids, including for example a fluid and an air flow. The heat exchanger comprises a plurality of tubes 2 according to the invention inside which a fluid flows. The tubes 2 are arranged parallel to each other in a stacking direction D, which is vertical in this case, and define a plurality of ducts in which a fluid can flow.

The space between two consecutive tubes 2 according to the invention defines a space 10 in which an air flow can flow in order to exchange heat with the fluid flowing in the tubes 2. To increase the heat exchange between the fluid and the air flow, a heat sink 8 in the form of fins is arranged in the space where the air flow flows. The function of these radiators 8 is to increase the surface in contact with the air flow, so as to optimize the heat exchange between the fluid and the air flow. To facilitate reading of fig. 1 and the vertical stack of tubes, the heat sinks 8 are only partially shown, it being understood that they may extend along the entire longitudinal dimension of the tubes between which they are arranged.

Each tube 2 according to the present invention is connected to the first header 12 and the second header 14, flows a fluid therethrough, and supplies the tube. The first header 12 is arranged to distribute the fluid entering the heat exchanger 1 to the different tubes 2 constituting said heat exchanger. The second header 14 is arranged to collect fluid that has passed through the tubes 2 so that it leaves the heat exchanger 1. The first header 12 and the second header 14 are opposite each other with respect to the stack of tubes 2, each tube extending longitudinally so as to be connected at a first end to the first header and at a second end to the second end.

The heat exchanger 1 also comprises means for putting these headers in communication with a circuit of fluid external to the heat exchanger 1, not shown here. Thus, the first header 12 is connected to a first connection end piece 16 through which fluid may enter the heat exchanger 1, and the second header 14 is connected to a second connection end piece 18 through which fluid may exit the heat exchanger 1.

Figure 2a shows a tube 2 constituting a first embodiment of the invention. The tube 2, having a substantially rectangular cross section, comprises an upstream end 21 and a downstream end 22, which are defined with respect to the flow direction E of the fluid inside the tube 2. The tubes 2 are connected at their upstream ends 21 to the first header 12 and at their downstream ends 22 to the second header 14.

Figure 2b shows a tube 2 constituting a second embodiment of the invention. This tube 2, having a substantially rectangular cross section, comprises a first longitudinal end 20 of the tube 2 (which is the upstream end) and a second longitudinal end 22 of the tube 2 (which is the downstream end), the upstream and downstream being defined with respect to the flow direction E of the fluid inside the tube 2. The tubes 2 are connected at an upstream end 20 to the first header 12 and at a downstream end 22 to the second header 14.

The tube 2 according to the invention is peculiar in that it comprises a plurality of perturbing means 4 for perturbing the fluid flow inside the tube 2, the perturbing means being respectively formed by a local depression in the tube wall towards the interior of the tube, some of these perturbing means being shown in figures 2a and 2 b. The specific shape and arrangement of the perturbation means will be described in more detail below.

The tube 2 according to the invention may optionally comprise at least one rib 24 arranged transversely to the tube in its direction of extension, for example when the tube is made by additive manufacturing. The rib or ribs help to increase the mechanical strength of the tube 2. In the example shown, the tube 2 comprises four ribs 24 arranged at regular intervals to divide the tube 2 into portions of equal length. It should be noted that the perturbation means 4 are preferably arranged on the tube 2 between two ribs 24.

Fig. 3 shows the arrangement of the interior of the tube 2 according to the invention. The shape of the tube 2 has a substantially rectangular cross section defined by two main walls (comprising a bottom wall 26 and a top wall 28) and two connecting walls (comprising a first vertical wall 30 and a second vertical wall 32) arranged at opposite ends of these main walls and respectively connecting one main wall to the other main wall to close the tube 2. The two main walls extend in a plane defined by a longitudinal direction and a transverse direction, and the connecting wall extends vertically the transverse end edges of the main walls, the tubes being open at their longitudinal ends to allow fluid to flow from one header to the other.

As shown in fig. 3, the top wall 28 extends mainly in a plane parallel to the plane in which the bottom wall 26 mainly extends, and the vertical connecting walls 30, 32 extend in a direction parallel to each other, it being understood that these connecting walls may be semicircular in shape due to the manufacturing method.

The set of walls defines a fluid flow cross-section. The tube is therefore characterized by a hydraulic diameter of between 1.2 and 2 mm. The hydraulic diameter is calculated excluding deformations that would result in the formation of a perturbation device.

An intermediate connecting wall 34 connects the top wall 28 and the bottom wall 26 to divide the tube 2 into two sub-channels, a first sub-channel 36 and a second sub-channel 38. The intermediate connecting wall 34 is advantageously perpendicular to the main walls 26, 28. It is in an intermediate position as long as it is arranged inside the tube between the vertical connecting walls 30, 32, which are equidistant from the first 30 and second 32 vertical walls. Thus, the first and second sub-channels 36, 38 are of equal size, each being defined by the two main walls 26, 28, the intermediate connecting wall 34 and the first or second vertical wall 30, 32.

The tube 2 constituting the invention has a plurality of perturbation means 4. The perturbation means 4 extend from the wall of the tube carrying them (i.e. the bottom wall 26 and/or the top wall 28) towards the interior of the tube 2, i.e. at least partially through the conduit defined by the first or second sub-channel 36, 38.

According to a first embodiment of the invention, the perturbation means are arranged in a given fluid flow channel such that the cross-sectional strip 20 of the tube comprises only the perturbation means, the longitudinal dimension of the cross-sectional strip 20 being equal to the longitudinal dimension of the perturbation means and comprising the entire perturbation means. In other words, for such a cross-sectional strip 20 of the tube, i.e. for a strip extending between a first plane perpendicular to the direction of fluid flow along the tube and a second plane perpendicular to the direction of fluid flow and parallel to the first plane, a single perturbation means is included in the strip.

In the example shown in fig. 3, for a given cutting plane, the perturbation device 4 extends from the top wall 28 of the tube 2 into the first sub-channel 36, and the perturbation device extends from the bottom wall 26 of the tube 2 into the second sub-channel 38.

The fact that a single perturbation means is present in the cross-sectional strip of the tube is to be understood as relative to each flow channel formed for the first and second sub-channels. In embodiments where the tube does not have an intermediate wall, the fact that there is a single perturbation means in the cross-sectional strip is understood to mean from one vertical wall to the other.

The perturbation means protruding from the top wall 28 of the tube 2 will now be described in more detail, for which it is pointed out that the top wall 28 comprises an inner face 280 turned towards the inside of the tube and an outer face 282 turned towards the outside of the tube.

Naturally, the following description of the perturbation means formed protruding from the top wall applies to the perturbation means formed protruding from the bottom wall.

The height 42 of the perturbation device 4 is measured between the inner face 280 of the wall of the tube 2 from which the perturbation device 4 extends and the apex 40 which extends protrudingly from the inner face 280, the height 42 being measured in a direction perpendicular to the outer face 282 of the wall. The apex 40 of the perturbation device 4 is the point of the perturbation device 4 furthest from the wall carrying the perturbation device 4, it being understood that this point of the perturbation device 4 is also the point furthest towards the interior of the tube and the respective sub-channels 36, 38. The perturbation device 4 according to the present invention has a height 42 between 0.1 mm and 0.5 mm. Advantageously, the perturbation device 4 according to the present invention has a height 42 comprised between 0.1 and 0.3 mm. In the example shown here, the perturbation device 4 has a height 42 of 0.25 mm.

It should be noted in fig. 3 that the perturbation devices 4 are arranged alternately in the longitudinal direction in case two perturbation devices are arranged on the top wall and then on the bottom wall of the same sub-channel, and in case two perturbation devices arranged on the same main wall enter the first sub-channel and then the second sub-channel. Due to this longitudinal alternation, the cross-sectional strip of the tube comprises only the perturbation means for the same flow channel, the longitudinal dimension of the cross-sectional strip being equal to the longitudinal dimension of the perturbation means and comprising the entire perturbation means. Thus, for a given flow path, the perturbation means do not overlap, helping to create a uniform perturbation along the flow path in the fluid flow. The fact that the perturbing means do not overlap also allows the chevrons to be arranged in different directions on the same flow channel, since the fluid perturbed by the first chevron is restored to a steady flow before hitting the second chevron, and thus the perturbation of the fluid can be controlled.

Figures 4a and 4b show in more detail the shape of the perturbation device 4 according to the present invention. The perturbation means 4 is in the shape of a chevron 43, i.e. a V-shape when viewed from above. The chevron 43 thus comprises two branches, a first branch 44 and a second branch 46, which correspond to the two branches of the "V", the two branches of the chevron 43 being connected at a tip 48. Each branch comprises a first free end and a second end opposite the first free end, the second ends of the branches contacting each other so as to form a tip 48 of the chevron 43.

As shown in particular in fig. 3 and 4, the perturbation device 4 has a flared shape at its base, so that it widens from the apex 40 to its base, in this case formed by the top wall 28 of the tube 2. The size of the flare depends, inter alia, on the constraints of the manufacturing process. The dimensions of the first and second branches forming the chevron "V" shape are defined at the apex 40 of the perturbation device, and the height 42 of the perturbation device 4 is constant along the entire transverse dimension of these branches.

According to a third embodiment of the invention, as shown in fig. 8 and 9, the chevron is formed by a plurality of local depressions 100 in series, each comprising an apex 140, such that the apexes 40 of the chevron are sequentially manufactured by the presence of successive apexes 140 of each local depression. Fig. 4b shows, in broken lines, the general shape of the theoretical vertices of a chevron, defined by these successive vertices of a local depression separated from each other, in particular as shown in fig. 3 and 4b, the perturbation means 4 having, at its base, a flared shape, such that it widens from the vertex 40 to its base, in this case formed by the top wall 28 of the tube 2, the size of this flare depending, inter alia, on the constraints of the manufacturing process. The dimensions of the first and second branches forming the chevron "V" shape are defined at the apex 40 of the perturbation device, and the height 42 of the perturbation device 4 is constant along the entire transverse dimension of these branches.

The length of the branch is measured between the first end of the branch and the second end of the branch at the apex 40 of the perturbation device. Accordingly, a first length 444 of the first branch 44 is measured between the first free end 440 of the first branch 44 and the second end 442 of the first branch 44. A second length 464 of the second branch 46 is measured between the first free end 460 of the second branch 46 and the second end 462 (at the tip 48) of the second branch 46.

According to a third embodiment of the invention, in which the perturbation means are formed by a plurality of local recesses in series, it should be understood that the free ends 440, 460 of the branches are formed by the vertices of the local recesses arranged at the ends of the local recesses in series.

The length of the branches of the perturbation device according to the invention is between 1.55 mm and 30 mm. In the example disclosed herein, the first length 444 of the first branch 44 is equal to the second length 464 of the second branch 46, it being understood that these lengths may be different from one another.

Furthermore, the overall longitudinal dimension of the perturbation device may be defined as the distance 400 separating the two engaging edges 52 the furthest from each other in the flow direction E. For example, the longitudinal dimension 400 may be between 1 and 20 millimeters.

Furthermore, the thickness 50 of the perturbation device 4 is measured between a plane perpendicular to the respective wall of the tube (in this case the top wall 28) and passing through the middle of the branches at the apex of the perturbation device and a parallel plane passing through the junction edge 52 where the perturbation device 4 meets the respective wall of the tube. The branches of the perturbation device according to the invention may in particular have a thickness 50 comprised between 0.5 and 5 mm. In the example shown, the thickness 50 of the first branch 44 is equal to the thickness 50 of the second branch 46, it being understood that they may be different from each other.

As previously specified for the third embodiment of the invention, the chevron is formed by a plurality of local depressions 100 in series, each comprising an apex 140 and a joint edge 152 at which they meet the respective wall of the tube, such that the chevron joint edge 52 is produced by adding together the joint edges 152 of each local depression. As a result, it will be appreciated that the joining edges have an irregular profile, as shown in fig. 4b, which also shows in dashed lines the general shape of the theoretical joining edges of the herringbone, which is defined by these successive joining edges 152 of the local depressions separated from each other.

Fig. 4a and 4b also show the opening angle of the perturbing means according to the invention, in which the angles 54, 56 are defined between the branches of the chevron and the straight line defined by the flow direction E. As described below, this angle may be between 20 ° and 160 ° depending on the desired orientation of the chevron relative to the direction of fluid flow. In the example shown, the first branch 44 and the second branch 46 are arranged at the same angle, in this case 60 °, with respect to the flow direction E of the fluid, it being understood that these angles may have different values, thus creating an asymmetry in the perturbing means.

According to a second embodiment of the invention, the tube comprises at least one perturbation device 4 comprising a local recess in the wall of the tube towards the inside of the tube 42, and having the shape of a chevron 43 comprising a geometrical parameter having a value varying between the tip 48 and each

free end

440, 460 of the branches 44, 46. This geometrical parameter that varies along the shape of the chevron may be, in particular:

the width of each branch, the value of the width of each branch being greater at the tip 48 than the value of the width of each

free end

440, 460 of the branch 44, 46; and/or

The angle formed between the branches of the chevron, the value of the angle at the tip 48 being smaller than the value of the angle at the free ends 440, 460 of the branches 44, 46; and/or

-the height of the chevron, the height value at the tip 48 being greater than the value of the height 424 of each

free end

440, 460 of the branch 44, 46.

Figure 5 shows the features in more detail with respect to the height of the perturbation means 4.

The height of the perturbation device 4 is measured between the inner face 280 of the wall of the tube 2 from which the perturbation device 4 extends and the apex at which it projects from the inner face 280, the height 42 being measured in a direction perpendicular to the inner face 280 of the wall.

According to this second embodiment of the invention, the height of the perturbation means 4 is not equal at any point of the perturbation means 4. More specifically, the height of the perturbation device 4 is variable in that at its tip 48, the height has a value different from the value of the height of the perturbation device 4 at the

free end

440, 460 of at least one branch 44, 46.

As shown in fig. 5, the height 420 of the tip 48 is measured between the inner face 280 of the wall of the tube 2 and the apex 422 of the tip 48 in a direction perpendicular to the inner face 280 of the wall. Similarly, the height 424 of the free ends 440, 460 of the branches 44, 46 is measured between the inner face 280 of the wall of the tube 2 and the apex 426 of the free ends 440, 460 of the branches 44, 46 in a direction perpendicular to the inner face 280 of the wall.

The height 420 of the tip 48 has a value between 0.1 mm and 0.5 mm. Advantageously, the height 420 of the tip 48 has a value between 0.3 and 0.5 mm. The height 424 of the free ends 440, 460 of the branches 44, 46 is equal or substantially equal to half the value of the height 420 of the tip 48. The free ends 440, 460 of the branches 44, 46 thus have a height 424 having a value of between 0.05 and 0.25 mm. Thus, the value of the height of the perturbation device at its tip is greater than the value of the height of the perturbation device 4 at each

free end

440, 460 of the branches 44, 46. More specifically, the variable height of the perturbation device may advantageously be such that the height of the perturbation device at its tip is equal to the sum of the height values of the perturbation device 4 at each

free end

440, 460 of the branches 44, 46.

The transition between the apex 422 of the tip 48 and the apex 426 of the free ends 440, 460 of the branches 44, 46 is effected by a regular ramp 428. "regular" is understood to mean that the ramp 428 describes a straight line between the apex 422 of the tip 48 and the apex 426 of the free ends 440, 460 of the branches 44, 46.

As previously described, the perturbation device 4 is arranged in the fluid flow channel in the pipe to perturb the fluid, and thus a front surface, which is the surface of the perturbation device 4 that is first exposed to the fluid flowing inside the pipe 2, and a rear surface, which is the opposite surface in the flow direction of the fluid, may be defined on the perturbation device.

Depending on the orientation of the perturbation device 4 in the tube 2, the front surface of the perturbation device 4 is either a first continuous surface 430 defined by the flared surface around the tip 48 of the perturbation device 4 when this tip is arranged upstream of the perturbation device 4 with respect to the direction of fluid flow inside the tube 2, or a second discontinuous surface 432 defined by the sum of the flared surfaces around the free ends of the branches when these free ends are arranged upstream of the perturbation device 4 with respect to the direction of fluid flow inside the tube 2.

For a given perturbation device 4, the surface area of the first continuous surface 430 forming the front or rear surface depending on the orientation of the perturbation device in the tube is equal to the value of the surface area of the second discontinuous surface 432 obtained by adding together the surface areas of each surface defined by the free ends 440, 460 of the branches surrounding the perturbation device 4. In other words, the front surface of the perturbation device 4 is the same size as the rear surface of the perturbation device, and therefore remains the same regardless of the orientation of the perturbation device with respect to the direction of fluid flow inside the tube 2.

Thus, a plurality of perturbation means may be provided in the fluid flow channel formed inside the tube, such that a first perturbation means is arranged in the tube in a first direction, for example in the fluid flow direction in which the free end of the branch is located upstream and is first reached by the fluid and the tip is located downstream, and a second perturbation means is arranged in a second direction, opposite to the first direction, such that the front surface of the first perturbation means is equal to the front surface of the second perturbation means.

This results in uniformity of flow disturbance, helping to ensure uniform and therefore efficient heat exchange.

Fig. 6 shows the arrangement of the interior of a tube 2 according to the invention in a top view showing the top wall 28 of the tube and the perturbation means 4 arranged thereon. To facilitate understanding of the arrangement of these perturbation means, this figure 6 also shows transparently the bottom wall 26 and the perturbation means 4 arranged thereon, as well as the intermediate wall 34, as it is hidden by the top wall 28. Thus, in this fig. 6, the perturbation means arranged on the bottom wall 26 are drawn in thin lines, while the perturbation means arranged on the top wall 28 are drawn in thick lines.

Regardless of the wall on which the perturbation device 4 is disposed, the perturbation device 4 extends towards the interior of the tube 2 and traverses the fluid flow of one or the other of the sub-channels 36, 38.

As shown in fig. 6, the perturbation means may alternate on the top wall 28 and on the bottom wall 26 in the longitudinal direction, i.e. along the inside of the tube, more particularly along the flow direction E of the fluid inside the sub-channel. Thus, the fluids are mixed by the perturbation means protruding from the top wall and thus towards the bottom wall, where they then encounter the next perturbation means protruding from this bottom wall.

The perturbing means 4 according to the present invention are arranged protruding from the wall of the tube, the orientation of which may depend on the flow direction E, in particular indicated by the arrows in fig. 2a, 2b, 4a, 4b and 6. To improve mixing of the fluids within the respective sub-channels, the turbulators protruding from the bottom wall 26 are arranged in a first direction and the turbulators protruding from the top wall 28 are arranged in a second direction opposite to the first direction. In other words, the chevrons forming the perturbation devices protruding from the bottom wall 26 are directed towards the downstream end 22 of the tube 2 so that fluid passing through the sub-channels into which the perturbation devices protrude eventually reaches its tip 48, whereas the chevrons forming the perturbation devices protruding from the top wall 28 are directed towards the upstream ends 20, 21 of the tube 2 so that fluid passing through the sub-channels into which the perturbation devices protrude first reaches its tip 48.

This results in a double alternation of the chevron arrangement forming the perturbation means along the same sub-channel. In the direction of flow of the fluid, a first chevron projects in a first direction from a first one of the main walls, then a second chevron projects in a second direction from a second one of the main walls, then a third chevron projects in the first direction from a first one of the main walls again, and so on.

It will be appreciated that this double alternation helps to mix the fluid within the sub-channels without causing pressure losses. All chevrons, i.e. the chevron projecting from the bottom wall and the chevron projecting from the top wall, may be oriented in the same flow direction of the fluid, if appropriate.

Furthermore, for example, in a variant provided as a non-limiting example, the perturbation means may be arranged in three lines in the longitudinal direction L of the tube 2, whereas in the arrangement shown in fig. 6 they are arranged in two lines per sub-channel. For example, two adjacent lines may be spaced from each other by a value between 3 and 5 millimeters; the spacing between each adjacent line of perturbation means may be the same.

In addition, the perturbation devices 4 may be arranged in series in each line, with a spacing between each perturbation device of the same line between 1.5 and 30 mm. Advantageously, the spacing has a value between 5 and 10 mm. The pitch is measured between the tips 48 of two consecutive chevrons of the same line.

Figure 7 shows a variant of the arrangement of the perturbation devices 4 on the tube 2 according to the present invention.

For example, the perturbation devices 4 are arranged in three lines 80 in the longitudinal direction L of the tube 2, whereas they are arranged in two lines per sub-channel in the arrangement shown in fig. 6. Two adjacent lines 80 are separated by a line spacing 82 measured between a first line 84 and a second line 86 in a direction perpendicular to the first line 84. The spacing between two adjacent lines corresponds to the value of the distance 82 between the lines, being between 1.5 and 30 mm. Advantageously, the interline distance 82 has a value between 3 and 5 mm. In the example described herein, the spacing between each adjacent line of perturbation means is the same.

The perturbation devices 4 are arranged in series in each line 80, the spacing 90 between each perturbation device on the same line being in this case between 1.5 and 30 mm. Advantageously, the spacing 90 has a value between 5 and 10 mm. The pitch is measured between the tips 48 of two consecutive chevrons of the same line. In the example described herein, the spacing 90 is the same along the entire line 80. The presence of the same spacing between successive chevrons of the same line of the perturbation device is particularly suitable for the aforementioned chevron arrangement.

The perturbation devices 4 of the first line 84 are longitudinally offset with respect to the perturbation devices 4 of the second directly adjacent line 86. In this arrangement, and in accordance with the above, the cross-sectional strip 20 of a given size of tube 2 comprises a single perturbation device 4. The cross-sectional strip 20 is a strip extending between a first plane perpendicular to the direction of fluid flow along the tube and a second plane perpendicular to the direction of fluid flow and parallel to the first plane, the longitudinal dimension of which is equal to the longitudinal dimension of the chevron. When the belt is centered on a chevron, the belt includes a single perturbation device with adjacent perturbation devices disposed on the outside of the belt.

In other words, the perturbation devices 4 of two adjacent lines are misaligned, and the perturbation device 4 of the first line 84 is arranged with a longitudinal offset 96 with respect to the other perturbation device of the second line 86. The longitudinal offset 96 is measured between a first transverse plane passing through the chevron tip 48 disposed at the nth position of the first line 84 of the perturbation device 4 and a second transverse plane passing through the chevron tip 48 disposed at the nth position of the second line 84 of the immediately adjacent perturbation device 4. The longitudinal offset 96 is greater than the longitudinal dimension 400 of the chevron as previously described, which means that the free ends of the legs of the chevron of an agitating device do not extend into the cross-sectional band that includes adjacent agitating devices. As shown in fig. 6, such a longitudinal offset 96 may result in a neutral space 97, i.e. a space where the flow between the apex of one perturbation device and the free ends of the branches of the immediately adjacent perturbation device is not perturbed. Thus, the cross-sectional strip 20 includes a single perturbation device.

The values given for the size and orientation of the chevrons and the spacing and positioning of the chevrons relative to each other are such that sufficient turbulence in the fluid flow can be obtained to facilitate heat exchange with air, but at a rate that minimizes pressure losses. These values may suitably differ from the indicated values if the presence of these chevrons in the pipe allows to shape the flow of fluid according to the requirements in the pipe.

The tube 2 according to the invention is made of a sheet of material arranged to allow sufficient heat exchange for the heat exchanger 1 to perform its function. In particular, it may be aluminum or an aluminum alloy.

The perturbation means 4 are each obtained by a plurality of local depressions made in series by stretching or punching the matrix defined by the sheet before it is folded to make the tube 2 according to the invention. The tube 2 is then brazed, either alone or with other identical tubes 2, to fix the final shape. The heat sink 8 may also be brazed to the tube 2 during this operation, or attached to the tube in a subsequent step. The heat exchanger 1 may then be installed by connecting the tubes 2 to the first header 12, the second header 14, the first sleeve 16 and the second sleeve 18 and then to the fluid circuit.

As described above, other manufacturing methods may be used. For example, the tube 2 according to the invention may be manufactured by an additive manufacturing method.

The fluid is a heat transfer liquid or a mixture of one or more heat transfer liquids selected from among the heat transfer liquids permitted and suitable for the use in question and one or more other fluids. The one or more heat transfer liquids may be especially water, deionized water or a mixture of ethylene glycol and water.

The heat exchanger 1 arranged in this way can function according to the following example. This is a non-limiting example and other functional modes may be envisaged.

The fluid flows in the tubes 2 forming the heat exchanger 1. More specifically, the fluid enters the first header 12 through a first sleeve 16, the first sleeve 16 being connected to a fluid circuit external to the heat exchanger 1. The fluid is distributed from the first header 12 and flows inside the different tubes 2 of the invention and, in the example shown, provided with intermediate walls inside the tubes, inside the different sub-channels formed in each of these tubes. The fluid flowing between the upstream ends 20, 21 and the downstream end 22 of the tube 2 is mixed by the perturbation means 4 arranged inside the tube 2. After flowing along the tubes 2, the fluid is collected in the second header 14 and then conveyed to the external circuit through the second sleeve 18.

In addition, the air flow flows in the space 10 between the tubes 2 of the heat exchanger 1. The fluid exchanges heat with the air flow through the walls of the tubes 2 and a heat sink 8 arranged in the space 10 between the tubes 2.

Thus, in an example of the function of the heat exchanger 1 arranged to cool the fluid flowing in the heat exchanger 1, the fluid flowing in the tube 2 transfers heat to the wall of the tube 2 and then to the radiator 8 arranged in contact with the wall of the tube 2, so that the air flow, when in contact with the radiator 8, can absorb the heat diffused by the radiator 8, so that the temperature rises.

With reference to fig. 8 to 13, the shape of the perturbation device, in particular equipped with a tube, according to a third embodiment of the invention is now described in more detail below.

Fig. 8 shows top wall 28 on which pairs of perturbation means are fabricated. As previously mentioned, the arrangement of the perturbation means has an effect on the flow of fluid inside the tube and the mixing of that fluid, but it will be appreciated that subsequent passages, particularly relating to the manufacture of the perturbation means, are applicable together with other arrangements of perturbation means along the tube.

The perturbation device 4 is formed on this top wall of the tube by a plurality of local depressions 100, the local depressions 100 being arranged in series in a herringbone fashion, i.e. having essentially two branches 44, 46 which meet at one of their ends to form the tip 48. As previously described, the branches of the perturbation device have

free ends

440, 460 which can be seen opposite the tip.

According to a third embodiment of the invention, a first partial recess 101 is made to form said tip 48, and a second partial recess 102 is made to form these free ends 440, 460, respectively. The third partial recess 103 is arranged between the first partial recess 101 and the second partial recess 102 to form the branches 44, 46, respectively. In the example shown in fig. 8 and 9, a single third partial recess 103 is arranged between the first partial recess forming the chevron tip and the second recess forming the free end of the branch, which single third partial recess 103 forms the body of the respective branch 44, 46. Fig. 10 schematically shows a variant according to which a plurality of third partial recesses 103 (in this case two) are arranged side by side to form one of the branches of the herringbone.

As previously described, each local depression 100 is caused by a deformation of the wall and therefore comprises an apex 140 extending into the tube, a joining edge 152 at which it meets the respective wall of the tube, and a flared connecting portion 110 connecting the apex to the joining edge. The shape of the flared connecting portion 110 is defined by the shape of the tool with the pattern for deforming the tube wall, and is particularly frusto-conical as shown.

In the configurations shown in fig. 8 and 9, the chevrons are oriented with respect to the flow direction E such that the tips of the chevrons form a leading edge, i.e. the part of the chevrons first impinged by the fluid flowing in the pipe, and such that the free ends of the branches respectively form a trailing edge, i.e. the part of the chevrons last impinged by the fluid flowing in the pipe.

The first local depression 101 is intended to form the tip of the chevron and thus the leading edge of the chevron, and the second local depression 102 is intended to form the free end of the chevron and thus the trailing edge of the chevron. According to a feature of the invention, it is desirable that the trailing edge has a similar shape, so that at least the second local recesses are made from the same pattern. In the example shown in fig. 8 and 9, all the partial recesses are made from the same pattern (i.e., a circular punch) with the result that the flared connecting portions 110 all have the same shape.

The spacing between the local depressions, more specifically the spacing between one local depression in series and the immediately adjacent local depression, is defined according to the desired shape of the chevron formed by these different local depressions. If it is desired to obtain a herringbone made in this way, the profile of which is substantially similar to that obtained by a single local depression of the herringbone-shaped pattern, the local depressions will be very close. If it is desired to obtain a chevron made up of a minimum number of local depressions, in order to limit the number of local deformation operations to be performed on the pipe wall, the local depressions may be spaced apart from one another and each branch of the perturbing means may have, for example, a single third local depression, as shown in fig. 8 and 9.

Advantageously, at least the third partial recesses 103 are manufactured close to each other, so that the flared connecting portion 120 of one third partial recess overlaps the flared connecting portion of an adjacent third partial recess, thereby forming an overlap region 122, as shown in particular in fig. 11 and 12. This will result in continuity of the segments connecting the leading and trailing edges and ensure that the fluid does not pass through the chevron through the holes left in the branch between the two local recesses.

Fig. 11 to 12 show various basic patterns that can be implemented to make local depressions that may form chevrons.

Fig. 11 illustrates the use of the circular pattern described above, in which case two third partial recesses are provided for each branch, so that it can be clearly seen that the flared connecting portion 110 of each partial recess 100 overlaps with the flared connecting portion of each adjacent partial recess.

FIG. 12 shows the local depressions made from a rectangular pattern, which steps the resulting chevron. Furthermore, the number of local depressions and their proximity to each other make it possible to obtain a continuous chevron, i.e. without interruption between the leading edge and the trailing edge. In this example, the rectangular patterns are arranged parallel to each other, but the local depressions may alternatively be inclined relative to each other, so that the fluid flow impinges on the chevrons configured in this way.

FIG. 13 illustrates a variation in which the patterns used to create the local depressions differ according to the chevron zones they contribute to. As previously mentioned, depending on the orientation of the chevrons in the pipe, the free ends forming the trailing or leading edges are manufactured in a pattern of the same shape, in this case circular. Instead, the third local depressions are made in a straight rectangular pattern aligned along a line connecting the vertices to the respective free ends of the chevrons. The first local depressions are made in a cuspated pattern. It will therefore be appreciated that the basic pattern shape is advantageously related to the function of the herringbone region that the basic pattern contributes to the manufacture: the pointed shape at the head of the chevron helps to divert the fluid to either side of the chevron, the straight shape on the branches helps to direct the fluid along the branches towards the trailing edges, and the rounded shape of these trailing edges allows for seamless continuity of fluid flow.

From the foregoing, it can be understood that the method for manufacturing a tube for a heat exchanger according to the third embodiment of the invention, as previously described, is particular in that it comprises a plurality of steps of pressing at least one wall of the tube, and in which at least a first set of local depressions resulting from these pressing steps is intended to form a chevron-shaped perturbation device. In other words, for a given perturbation device, a plurality of pressing steps are performed on a defined area of the wall forming the tube. Simultaneously with or after the step provided for forming the first perturbation means, a plurality of further pressing steps are provided in order to form further perturbation means. Furthermore, for a given perturbation device, it is also possible to perform a plurality of pressing steps, either consecutively or simultaneously. In the above example, in which the local recesses, in particular the third local recesses corresponding to the branches of the herringbone, are configured to overlap so as to form a continuity of the herringbone formation, advantageously the pressing steps are carried out successively so that the formation of the local recesses, in particular the formation of their flared connecting portions, overlaps with the previous local recesses, in particular their flared connecting portions.

The above description clearly illustrates how the invention can be used to achieve the stated objects and in particular proposes a tube for a heat exchanger comprising at least one perturbation means shaped, arranged on a wall and oriented in the direction of flow of the fluid in the tube, so as to facilitate the creation of significant perturbations in the fluid by having interference means respectively chevron-shaped and easy to manufacture, so as to increase the amount of heat exchange, without however causing significant pressure losses.

Of course, the person skilled in the art may make various modifications to the flow duct group or heat exchanger just described as a non-limiting example, as long as a perturbing means having a herringbone shape is produced, for example by means of a plurality of local recesses.

In any case, the invention is not limited to the embodiments specifically described herein, and extends in particular to all equivalent arrangements and any technically effective combination of such arrangements.

Claims

1. A tube (2) for a heat exchanger comprising at least one perturbation device (4) for perturbing the flow of a fluid able to flow in the tube, the perturbation device (4) comprising a local recess in the wall of the tube towards the inside of the tube (42) and having the shape of a chevron (43), the chevron (43) comprising at least a first branch (44) and a second branch (46) extending from a tip (48) towards a free end (440, 460).

2. The tube (2) according to claim 1, defining a flow channel for a fluid that can flow in the tube mainly in a first direction, and comprising a plurality of perturbation means (4) for perturbing the flow of the fluid along the flow channel, and wherein the perturbation means (4) are in the shape of chevrons (43) arranged along the fluid flow channel such that a cross-sectional strip (20) of the tube, having a longitudinal dimension equal to the longitudinal dimension of the perturbation means and comprising the entire perturbation means, comprises only the perturbation means (4).

3. The tube (2) according to claim 2, wherein the chevron (43) forming the perturbation means (4) comprises at least two branches (44, 46) extending from a tip (48), the branches (44, 46) being defined by a length (444, 464) of between 1.55 and 30 mm.

4. The tube (2) according to claim 3, wherein at least one branch (44, 46) is arranged with an extension angle (54, 56) between 20 ° and 160 ° with respect to the flow direction (3) of the fluid.

5. The tube (2) according to any one of the preceding claims, wherein the perturbation means (4) is defined by a height (42) comprised between 0.1 and 0.5 mm, said height (42) being measured between an inner face of the wall of the tube (2) and an apex (40) of the perturbation means (4) in a direction perpendicular to the wall of the tube (2).

6. The tube (2) according to any one of the preceding claims, wherein the perturbation means (4) is defined by a thickness (50) of between 0.5 and 5 millimetres, said thickness (50) being measured between a plane passing through the middle of the branches at the apex of the perturbation means and a parallel plane passing through the junction edge (52) where the perturbation means (4) meets the respective wall of the tube.

7. The tube (2) according to any one of the preceding claims, wherein the perturbation means (4) are arranged in at least two lines (80) in the longitudinal direction of the tube (2), the spacing between two consecutive lines (82) being between 1.5 and 30 mm.

8. The pipe (2) according to claim 7, wherein the perturbation means (4) of the at least one first line (84) are arranged with a longitudinal offset (96) with respect to the perturbation means (4) of the at least one second line (86).

9. The tube (2) according to any one of claims 7 or 8, wherein two successive perturbation means of the same line (80) are spaced apart by a spacing (90) of between 1.5 and 30 mm.

10. The tube (2) according to any one of the preceding claims, wherein the perturbation means (4) are arranged alternately on a top wall (28) and an opposite bottom wall (26), all being arranged inside the passage defined between these two walls.

11. The tube (2) according to claim 1, wherein at least one geometrical parameter of the chevron shape has a value that varies between the tip (48) and each free end (440, 460) of a branch (44, 46).

12. The tube (2) according to claim 11, wherein the at least one geometric parameter that varies is the width of each branch, the width of each branch at the tip (48) having a value greater than the width of each free end (440, 460) of the branch (44, 46).

13. The tube (2) according to any one of claims 11 and 12, wherein the at least one geometric parameter that varies is the angle formed between the branches of the chevron, the value of the angle at the tip (48) being smaller than the value of the angle at the free ends (440, 460) of the branches (44, 46).

14. The tube (2) according to any one of claims 11 to 13, wherein the at least one geometric parameter that varies is the height of the chevron, the height at the tip (48) having a value greater than the height (424) of each free end (440, 460) of the branch (44, 46).

15. The tube (2) according to claim 14, wherein the height (420) of the tip (48) has a value equal or substantially equal to twice the value of the height (424) of the free end (440, 460) of the branch (44, 46).

16. The tube (2) according to claim 14, wherein the height (420) of the tip (48) has a value equal or substantially equal to the sum of the values of the heights (424) of each of the free ends (440, 460) of the branches (44, 46).

17. The pipe (2) according to claim 16, wherein the perturbation means (4) are arranged in series between the first longitudinal end (20) of the pipe (2) and the second longitudinal end (22) of the pipe (2), at least one of the height values (420, 424) increasing from one perturbation means (4) to the next in the series.

18. The tube (2) according to any of claims 11 to 17, wherein the height (420) of the tip (48) is between 0.1 and 0.5 mm.

19. The tube (2) according to any one of claims 11 to 18, wherein the perturbation devices (4) are arranged in at least two lines (80) in the longitudinal direction of the tube (2), the perturbation devices of at least one first line (84) being arranged with a longitudinal offset (96) with respect to the perturbation devices (4) of at least one second line (86).

20. The pipe (2) according to claim 1, wherein the perturbation means (4) are formed by a plurality of local depressions (100) in the wall of the pipe (2) towards the inside of the pipe (2), arranged with respect to each other in the shape of chevrons (43).

21. The tube (2) of claim 20, wherein the chevron (43) includes at least one tip (48), two branches (44, 46) joined at one end to form a tip (48) and having a free end (440, 460) opposite the tip.

22. The tube (2) according to claim 21, wherein a first partial recess (101) is made to form the tip (48) and a second partial recess (102) is made to form one of the free ends (440, 460) of the two branches (44, 46), respectively.

23. The tube (2) according to claim 22, wherein a third local recess (103) is arranged between the first and the second local recess to form a branch (44, 46).

24. The tube (2) according to any of claims 20 to 23, wherein each local depression (100) comprises an apex (140) and a joining edge (152) at which it meets the wall of the tube, the local depression comprising a connecting portion (110) which flares between the joining edge and the apex.

25. The tube (2) according to claims 23 and 24, wherein at least third partial recesses (103) are made close to each other such that the flared connecting portion (110) of one third partial recess overlaps the flared connecting portion of an adjacent third partial recess.

26. The tube (2) according to any one of claims 24 or 25, wherein the flared connection portion (110) of each local recess (100) has the same shape.

27. The tube (2) according to any one of claims 20 to 26, wherein the perturbation means (4) are arranged alternately on a top wall (28) and an opposite bottom wall (26), all being arranged inside the channel defined between these two walls.

28. A heat exchanger comprising a plurality of tubes (2), at least one tube (2) of which (2) is a tube according to any one of the preceding claims, said tubes defining internally, on the one hand, a flow circuit for a fluid which can be disturbed in transit by the presence of said chevrons forming a means of disturbance, said tubes defining between them, on the other hand, a flow circuit for air.

29. A method for manufacturing a tube for a heat exchanger as claimed in any one of claims 20 to 27, said method comprising performing steps of pressing at least one wall of said tube, at least one first set of local depressions resulting from the pressing steps forming chevrons.