WO2021259763A1

WO2021259763A1 - Duct for heat exchanger

Info

Publication number: WO2021259763A1
Application number: PCT/EP2021/066455
Authority: WO
Inventors: Erwan ETIENNE; Yolanda Bravo; Kamel Azzouz
Original assignee: Valeo Systemes Thermiques
Priority date: 2020-06-24
Filing date: 2021-06-17
Publication date: 2021-12-30
Also published as: FR3111972B1; FR3111972A1

Abstract

The invention relates to a duct (12) for conveying a fluid within a heat exchanger, the duct comprising a plurality of protrusions (28) and a plurality of raised patterns (30), the plurality of protrusions (28) and the plurality of raised patterns (30) being distributed over a length (L) of the duct (12), the plurality of raised patterns (30) being placed on an inner surface (26) of the duct (12).

Description

CONDUIT FOR HEAT EXCHANGER

Technical area

The invention relates to a conduit for transporting a fluid inside a heat exchanger, in particular, a heat exchanger for an engine of a motor vehicle, as well as an associated heat exchanger.

Prior art

Motor vehicles, whether combustion, electric or hybrid, need to dissipate excess heat from the engine in order to prevent the engine from overheating.

Generally, engine cooling is obtained by means of a heat transfer fluid circulating in a cooling circuit. In particular, the heat transfer fluid is a cooling liquid transporting the excess calories generated at the engine level to an engine radiator. The cooling circuit generally includes a heat exchanger with at least one duct through which the coolant circulates.

The movement of coolant within each heat exchanger duct is generated by an electric pump. However, the development of electric or hybrid vehicles requires the use of increasingly small electric pumps, thereby drastically reducing the flow of the fluid in the exchanger and the flow of the fluid becomes laminar, characterized by a Reynolds number. less than 3000.

This results in the formation of a boundary layer of fluid in the exchanger conduits, in which the fluid velocity is zero, and which interferes or even prevents the transmission of heat from outside the conduit to the coolant.

The aim of the invention is to at least partially remedy this drawback.

Disclosure of the invention

To this end, the invention relates to a conduit for transporting a fluid inside a heat exchanger, the conduit comprising a plurality of protrusions and a plurality of raised patterns, the plurality of protuberances and the plurality of raised patterns being distributed over a length of the duct, the plurality of raised patterns being placed on an internal surface of the duct.

Thus, the presence of the plurality of patterns in relief on the internal surface of the duct reduces or even destroys the boundary layer, which allows the flow of the fluid to be of the pseudo-turbulent type, and consequently reactivates the heat exchanges of optimally.

In addition, the presence of the plurality of raised patterns on the internal surface of the duct can cause a decrease in the surface tension of the fluid layer in contact with the internal surface of the duct, thus limiting the average thickness of the layer. limit.

In another aspect, the plurality of relief patterns are placed on at least one of the plurality of protrusions.

According to another aspect, the plurality of raised patterns is placed only on said plurality of protuberances.

In another aspect, a depth of at least one of the relief patterns is mesoscopic.

According to another aspect, the depth of at least one of the relief patterns is between 75 µm and 250 µm, preferably between 100 µm and 200 µm.

In another aspect, a depth of at least one of the relief patterns is microscopic.

According to another aspect, the depth of at least one of the relief patterns is between 2 µm and 150 µm, preferably between 5 µm and 100 µm.

In another aspect, at least some relief patterns are aligned in a direction forming a non-zero angle with a direction of flow of fluid within the conduit.

In another aspect, each relief pattern forms with the direction of flow of the fluid an angle of between 35 ° and 100 °, preferably between 45 ° and 90 °.

According to another aspect, each relief pattern of the plurality of relief patterns is identical. According to another aspect, at least one relief pattern of the plurality of relief patterns is different from the other relief patterns.

In another aspect, each protuberance forms a hollow on an outer surface of the duct.

According to another aspect, each protuberance is formed by a part assembled on the internal surface of the duct.

According to another aspect, each relief pattern is obtained by surface texturing by laser and / or by mechanical methods.

According to another aspect, a heat exchanger is described comprising at least one duct as described above.

In another aspect, the heat exchanger is of the low temperature radiator type.

In another aspect, the heat exchanger is configured to effect heat exchange between a first liquid fluid and a second liquid fluid or between a first liquid fluid and a second gaseous fluid.

According to one aspect of the invention, the heat exchanger is a tube exchanger.

According to another aspect of the invention, the heat exchanger is a plate exchanger.

According to one aspect of the invention, the conduit is formed between two plates.

Brief description of the drawings

Other features, details and advantages of the invention will become apparent on reading the detailed description below, and on analyzing the accompanying drawings, in which:

[Fig. 1] is a schematic front view of a heat exchanger.

[Fig. 2] is a perspective view and a detail of a duct of the heat exchanger of Figure 1 according to the present invention.

[Fig. 3] shows a schematic view of a longitudinal section of the duct of FIG. 2. [Fig. 4] is a schematic view of a side section of a relief pattern according to the present invention.

Description of embodiments

In the remainder of the description, elements that are identical or have an identical function bear the same reference sign. For the sake of brevity of the present description, these elements are not described in detail in each embodiment. On the contrary, only the differences between the variant embodiments are described in detail.

FIG. 1 shows a heat exchanger 10 for an engine, in particular for a motor vehicle engine. Preferably, the exchanger 10 is a low temperature radiator type exchanger.

As will be detailed later, the exchanger 10 is configured to allow heat exchange between a first fluid and a second fluid. The first fluid can be a liquid fluid or a gaseous fluid. Likewise, the second fluid can be a liquid fluid or a gaseous fluid.

Thus, the exchanger 10 is configured to effect heat exchange between two liquid fluids or between a liquid fluid and a gaseous fluid. The exchanger 10 can also be configured to allow heat exchange between two gaseous fluids.

The heat exchanger 10 comprises at least one duct 12. Preferably, the exchanger 10 comprises a plurality of ducts 12.

Each conduit 12 extends between a first end 14 and a second end 16. Preferably, the conduits 12 are rectilinear. Thus, a distance between the first end 14 and the second end 16 corresponds to a length L of the duct 12.

In FIG. 1, all of the conduits 12 in the exchanger 10 are, for example, mutually parallel in a longitudinal direction A and distributed so as to form a row of conduits 12. Of course, the invention is not not limited to this configuration and the conduits can be distributed in several rows of conduits. The conduits 12 are intended to be crossed by said first fluid. The first fluid is a heat transfer fluid. The heat transfer fluid is a liquid fluid or a gaseous fluid. For example, the heat transfer fluid can be water or oil.

The exchanger 10 further comprises at least one heat transfer fluid intake manifold making it possible to direct the heat transfer fluid towards the interior of the conduits 12. In FIG. 1, the exchanger 10 comprises a first intake manifold 18 and a second intake manifold 20 for the coolant.

Preferably, the intake manifolds 18, 20 extend in a direction substantially perpendicular to the direction A of the ducts 12.

The first intake manifold 18 is connected to the first end 14 of the ducts 12. The second intake manifold 20 is connected to the second end 16 of the ducts 12. Thus, the heat transfer fluid circulating in the first and second manifolds. inlet 18, 20 accesses the interior of the conduits 12 via the first and second ends 14, 16.

Now, one of the conduits 12 according to the present invention is described in more detail, with reference to Figures 2 to 4.

As illustrated in Figure 2, the duct 12 has a side wall 22 extending between the first end 14 and the second end 16 in the longitudinal direction A. The side wall 22 includes an outer surface 24 and an inner surface 26.

When the heat transfer fluid circulates in the conduit 12, the side wall 22 forms an exchange surface between said heat transfer fluid and said second fluid. The second fluid is a fluid circulating outside the conduit 12. The second fluid is a liquid fluid or a gaseous fluid.

As illustrated in Figures 2 and 3, the duct 12 also comprises a plurality of protuberances 28 arranged on the side wall 22. The protuberances 28 make it possible to increase the exchange surface, which optimizes the heat exchanges between the heat transfer fluid and the second fluid. The plurality of protrusions 28 is distributed over the length L of the duct 12. As clearly shown in FIG. 3, each protrusion 28 projects inside the duct 12, a hollow being formed on the outer surface 24.

According to an alternative not shown, each protuberance 28 is formed by a part assembled on the internal surface 26, with or without formation of hollows on the external surface 24.

Preferably, the protuberances 28 are regularly distributed over the side wall 22. For example, the protuberances 28 can be arranged so as to form one or more rows of protuberances 28.

Alternatively, the protuberances 28 are distributed randomly on the side wall 22.

Preferably, the protrusions 28 are identical, and each protuberance 28 has the same shape and dimension as the other protuberances 28. For example, the protrusions 28 have a substantially ovoid shape.

Alternatively, at least one protuberance 28 has a shape and / or a dimension different from the other protuberances 28.

As shown in Figure 2, the protuberances 28 can all have the same orientation. Alternatively, the protuberances 28 have different orientations from one another.

As also emerges from the figures, the duct 12 comprises a plurality of patterns in relief 30.

The relief patterns 30 make it possible to reduce the surface tension of the layer of heat transfer fluid in contact with the internal surface 26 of the duct 12, thus limiting the formation of the boundary layer.

In the figures, the plurality of patterns in relief 30 is arranged on the internal surface 26 of the duct 12. The patterns in relief 30 are distributed over the length L of the duct 12.

Preferably, as illustrated in the figures, the relief patterns 30 are arranged only on the protuberance (s) 28. Alternatively, the relief patterns 30 can be arranged on an area of the internal surface 26 devoid of protuberances 28.

For example, the plurality of raised patterns 30 can be placed on at least one of the protrusions 28. Preferably, the plurality of raised patterns 30 is placed only on the plurality of protrusions 28.

As shown in Figure 4, each relief pattern 30 includes at least one protrusion 32 and at least one depression 34.

A depth D of each relief pattern 30 is defined as a distance measured between the depression 34 and a point belonging to a plane P substantially tangent to the projection 32, the point being substantially parallel to the depression 34.

Advantageously, the depth D of the relief patterns 30 is of mesoscopic or microscopic dimension. By mesoscopic depth is meant a depth of between 75 μm and 250 μm, preferably between 100 μm and 200 μm. By microscopic depth is meant a depth of between 2 μm and 150 μm, preferably between 5 μm and 100 μm.

In conduit 12, the depth D of at least one of the relief patterns 30 may be mesoscopic. Also, the depth D of at least one of the relief patterns 30 may be microscopic. Thus, the duct 12 may include certain patterns in relief 30 at mesoscopic depth and certain patterns in relief 30 at microscopic depth. Alternatively, all of the patterns in relief 30 are at mesoscopic depth or all of the patterns in relief 30 are at microscopic depth.

As shown in FIG. 3, at least some relief patterns 30 are aligned in a direction forming a non-zero angle with a direction of flow of the heat transfer fluid inside the duct 12. In particular, the angle a is between 35 ° and 100 °, preferably between 45 ° and 90 °. For example, the direction of flow of the heat transfer fluid is substantially parallel to the longitudinal direction A.

Each relief pattern 30 may be identical. Alternatively, at least one relief pattern 30 is different from the other relief patterns. The relief patterns 30 can be obtained by laser surface texturing. The relief patterns 30 can also be obtained by mechanical methods. For example, the relief patterns can be obtained by microfilling or additive manufacturing. As already indicated, the relief patterns 30 prevent the formation of a boundary layer of heat transfer fluid on the internal surface 26 of the duct 12, which makes it possible to transform the flow of the heat transfer fluid inside the duct 12 from a flow of laminar type to a flow of pseudo-turbulent type, even if the Reynolds number is less than 3000. The presence of the patterns 30 directly and only on the protuberances 28 ensures in particular an optimization of the transformation into pseudo-turbulent flow.

The present disclosure is not limited to the example described above with reference to the figures. On the contrary, the present disclosure encompasses all the variants and combinations that a person skilled in the art may envisage in the context of the protection sought.

Claims

[Claim 1] A conduit (12) for transporting fluid within a heat exchanger (10), the conduit comprising a plurality of protrusions (28) and a plurality of raised patterns (30), the plurality of protrusions (28) and the plurality of raised patterns (30) being distributed over a length (L) of the duct (12), the plurality of raised patterns (30) being placed on an internal surface (26) of the duct (12) .

[Claim 2] A conduit (12) according to claim 1, wherein the plurality of raised patterns (30) are placed on at least one of the protrusions (28) of the plurality of protrusions (28).

[Claim 3] A conduit (12) according to claim 1 or claim 2, wherein the plurality of relief patterns (30) are placed only on said plurality of protrusions (28).

[Claim 4] A conduit (12) according to any preceding claim, wherein a depth (D) of at least one of the relief patterns (30) is mesoscopic.

[Claim 5] A conduit (12) according to the preceding claim, in which the depth (D) of at least one of the relief patterns (30) is between 75 pm and 250 miti, preferably between 100 pm and 200 pm .

[Claim 6] A conduit (12) according to any preceding claim, wherein a depth (D) of at least one of the relief patterns (30) is microscopic.

[Claim 7] A conduit (12) according to the preceding claim, in which the depth (D) of at least one of the relief patterns (30) is between 2 pm and 150 pm, preferably between 5 pm and 100 pm .

[Claim 8] A conduit (12) according to any preceding claim, wherein at least some relief patterns (30) are aligned in a direction forming a non-zero angle (a) with a direction of fluid flow at inside the duct (12).

[Claim 9] A conduit (12) according to the preceding claim, in which each relief pattern (30) forms with the direction of flow of the fluid an angle (a) of between 35 ° and 100 °, preferably between 45 ° and 90 °.

[Claim 10] A heat exchanger (10) comprising at least one duct (12) according to any one of the preceding claims.