WO2017021416A1

WO2017021416A1 - Heat exchanger

Info

Publication number: WO2017021416A1
Application number: PCT/EP2016/068452
Authority: WO
Inventors: Thomas Schiehlen; Holger Schroth
Original assignee: Mahle International Gmbh
Priority date: 2015-08-06
Filing date: 2016-08-02
Publication date: 2017-02-09
Also published as: US20190242658A1; EP3332206A1; EP3332206B1; DE102015215053A1; CN107850402A

Abstract

The invention relates to a heat exchanger (1), comprising tubes (2) and corrugated fins (3) arranged therebetween, which corrugated fins have straight flanks (4) and have corrugation peaks (7) and corrugation toughs (6) each having a curve (5). It is essential to the invention that the curve (5) of a corrugation peak (6) has a curved first segment (9) and a linear second segment (10), wherein the second segment (10) is twice as long as the first segment (9), and the first segment (9) and the second segment (10) have an opposite slope of 0.1 to 0.5%; or that the curve (5) of a corrugation peak (6) has a curved first segment (9) and an equally long second segment (10) curved in the same direction, wherein, in the case of unloaded corrugated fins (3), a tolerance distance a remains between two adjacent corrugation peaks (6), which tolerance distance a is dimensioned in such a way that the tolerance distance a goes to zero in the state of installation in the heat exchanger (1) and the corrugation peaks (6) thus lie in contact with each other.

Description

Heat exchanger

The present invention relates to a heat exchanger with tubes and interposed corrugated fins with straight flanks and each having a curvature troughs and crests, according to the preamble of claim 1.

From DE 10 2006 035 209 A1 a generic heat exchanger with tubes and corrugated fins arranged therebetween is known, which have wave crests and wave troughs and flanks arranged therebetween, the flanks being equipped with cuts exposed from their planes. The flanks go over a bending edge in the wave crests or wave troughs over, these bending edges are designed weakened, so that the self-adjusting in the bending springback is reduced. This is intended to be

Heat exchangers can be provided with improved efficiency.

From DE 201 18 51 1 U1 is a heat exchanger network and a so

equipped heat exchanger known, wherein the heat exchanger network has a plurality of flat tubes and arranged between the flat tubes, in heat-conducting contact with these lamellae and wherein the heat-conducting contact is made solely by mutual tension of the flat tubes and fins. The slats are in the direction of

Tension elastically deformable, whereby an assembly effort is to be reduced.

In order to achieve the highest possible performance in heat exchangers, corrugated ribs are used between individual tubes of such heat exchangers in a known manner, which improves the heat transfer usually soldered to the pipes. As an alternative to a soldering an adhesive bond for fixing the corrugated fins on the pipes is known, so far, the adhesives used for this purpose, for example with

Wärmeleitpartikeln from boron nitride or aluminum were equipped to the

To improve the thermal conductivity of the adhesive. such

Wärmeleitpartikel however, adversely affect the price of the adhesive and its processing. Also known is a soldered network

However, for this purpose, two manufacturing processes must be combined, which also has a negative effect on the cost.

A disadvantage of the soldering constructions known from the prior art is that they are designed to tolerate manufacturing tolerances arising in the

Assembling revealed to balance over the tube geometry. However, this is not possible with a purely glued heat exchanger and, for example, with an extruded tube geometry. For this reason, for example, corrugated fins are used, which can take such a compensation function.

The present invention deals with the problem, for a

Heat exchanger of the generic type to provide an improved or at least one alternative embodiment, which overcomes in particular the disadvantages known from the prior art.

This problem is inventively achieved by the subject matter of

independent claim 1 solved. Advantageous embodiments are

Subject of the dependent claims.

The present invention is based on the general idea to be able to create a heat exchanger on the one hand, which can be glued, and On the other hand, however, this comparatively inexpensive and with

corresponding tolerance compensation options and a high

Equip heat exchanger performance. The heat exchanger according to the invention has in a known manner tubes and interposed corrugated fins with straight flanks and each having a curvature having wave troughs and wave crests. The curvature of a wave crest can alternatively be designed in two embodiments according to the invention. With the two

Alternatives are the wave crests optimized to a

Minimum investment is enforced by a spring action, creating a

improved heat transfer capability and thus a minimum system performance can be guaranteed. The shape of the wave crest of such

The corrugated fin according to the invention is in bionic form based on the shape of a human foot. It is particularly advantageous that results in a pressure-stable rib or flank of the corrugated fin, which avoids buckling under pressurization. In principle, the first alternative

Embodiment of a curvature of a wave crest on a curved first portion and a linear second portion, wherein the second portion is twice as long as the first portion and wherein the two portions have an opposite slope between 0.1 and 0.5%. This means that the domed first section has a positive slope of +0.1 to + 0.5% while the linear second section has a negative slope of -0.1 to -0.5%. The slope of the curved first section is determined between its beginning and end point. By such a curvature of the wave crests of the corrugated fin, on the one hand, a required tolerance compensation can be achieved and, on the other hand, a two-dimensional contact of the corrugated fin on the tubes, whereby a high heat transfer and thus high performance of the heat exchanger can be achieved. The troughs are here

Of course, according to the wave mountains trained, only in

inverted shape, ie for example by an upside-down first and second section. The wave crest can thus correspond to a mirrored wave valley or vice versa.

In the second alternative embodiment of the curvature of a wave crest also has this a curved first and a curved second portion, but in this case the same length, wherein the first

Section again passes over a high point in the second section and wherein at unloaded corrugated fins between two adjacent wave crests a tolerance distance a remains, which is dimensioned so that it is pressed when installed in the heat exchanger state to zero and thereby abut the wave crests to block each other. The two sections are arranged in mirror image to each other, as long as the mirror axis passes through the high point. The horizontal tolerance distance a between two wave crests or between two wave troughs can thus preset determine a possible vertical spring travel, as contact after exhausting this spring travel two adjacent wave peaks or troughs and thus creates a very stable arch structure. As a result, on the one hand prevents buckling of the individual flanks or corrugated fins and on the other hand created a sufficient pressure-stable surface to superfluous

To displace adhesive from the gap between the wave crest and the wave trough and the tube. This is especially important for optimum heat transfer. The remaining adhesive layer is thereby reduced to a minimum while ensuring freedom from bubbles.

In general, the following advantages can be achieved with the heat exchanger according to the invention:

Compensation of manufacturing tolerances, which must be balanced in the assembly of the system corrugated fin and pipe, resulting in extremely thin Adhesive coating thicknesses are feasible and thereby the performance of

Heat exchanger can be increased,

Enlargement of a contact surface of the corrugated fin on the pipe and thus an improved heat transfer, a spring effect by balancing the manufacturing tolerances in the assembly and creating a uniform adhesive layer in a precisely predefined area, a pressure stability of the corrugated fin without the risk of buckling at the same thickness, lower costs in terms on energy and resources as well as the

Possibility of connecting corrugated fins and pipes made of different materials, since the adhesive layer is electrically insulating and thus prevents contact corrosion, considerable CO2 savings in production due to the omission of brazing furnaces and the energy required for this purpose.

In a further advantageous embodiment of the solution according to the invention, an opposing gradient of the first and second sections is about 0.3-0.4%. This makes it possible to create a comparatively shallow wave crest or a comparatively shallow wave trough, which on the one hand enables a flat and thus good heat transfer connection to the pipe and

on the other hand allows the desired tolerance compensation. In a further advantageous embodiment of the solution according to the invention, an adhesive layer, in particular by laminating, is applied on an outer side of the tubes. By means of such lamination, the adhesive layer can thus be applied, in particular in the form of an adhesive film or an adhesive film, whereby the application of the adhesive layer is possible not only economically but also of extremely high quality.

In a further advantageous embodiment of the solution according to the invention, the corrugated fins are made of a good thermally conductive material, preferably aluminum, copper, etc. This can also be a

Material combination are thought, as the adhesive layer has an insulating effect and thus a contact corrosion is prevented.

The heat exchanger is expediently designed as an evaporator, as a radiator, as a condenser, as a charge air cooler, as a chiller, as an oil cooler, as a radiator or as a PTC heater. Already this non-exhaustive enumeration gives an idea of the manifold fields of application for the corrugated fins according to the invention and also for the heat exchanger according to the invention.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated

Description of the figures with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention. Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, in each case schematically,

Fig. 1 is a sectional view through an inventive

Heat exchanger with corrugated fins according to a first alternative embodiment,

Fig. 2 is a detailed view of the corrugated fin according to the first alternative

embodiment,

Fig. 3 is a representation as in Fig. 1, but with corrugated fins according to a

second alternative embodiment,

Fig. 4 is a detailed view of the corrugated fins according to the second alternative

Embodiment.

According to FIGS. 1 and 3, a heat exchanger 1 according to the invention, which can be designed, for example, as an evaporator, as a radiator, as a condenser, as a charge air cooler, as a chiller, as an oil cooler, as a radiator or as a PTC heater, has tubes 2 and interposed therebetween Corrugated ribs 3 with straight edges 4 and each having a bulge 5 having troughs 6 and wave crests 7 (see also Figs., 2 and 4). The corrugated fins 3 are glued to the tubes 2 via an adhesive layer 8. In order now to achieve the best possible heat transfer between the corrugated fins 3 and the tubes 2 and at the same time a possible compensation of manufacturing tolerances can, the bulge 5 of a wave crest 6 according to the invention according to two alternative embodiments formed:

In the first alternative embodiment of the curvature 5 according to the invention, this has a curved first section 9 and a linear second section 10, wherein the linear second section 10 is twice as long as the first section 9. The length used for this refers to an extension along a central axis 12. The curved first portion 9 has a slope of 0.1 -0.5%, preferably between +0.3 and +0.4%, while the linear second portion 10 has a gradient of -0 , 1 to -0.5%, preferably from -0.3 to -0.4%. The height of the curvature 5 to the transition into the respective flanks 4 is referred to as shown in FIGS. 2 and 4 with m. The slope of the curved first section 9 is determined between its beginning and end point, wherein for the slope S = m / L applies.

Considering the second alternative embodiment of the corrugated fin 3 according to the invention, its convexity 5 of a wave crest 6 (see Fig. 4) has a curved first section 9 and a second section 10 curved in the same direction and having the same length L (along the central axis 12) and are therefore formed the same length. When unloaded corrugated fin 3 remains between two adjacent wave crests 5, a tolerance distance a, which is dimensioned such that it goes to zero when installed in the heat exchanger 1 state and thereby the wave crests 6 rest on block to each other.

The difference between the wave crests 6 and the wave troughs 7 can only be seen in a reflection with respect to the central axis 12, so that the wave crests 6 correspond to the wave troughs 7. The adhesive layer 8 is applied to the outside of the tubes 2, for example by laminating, whereby such an adhesive layer 8, for example in the form of an adhesive film or an adhesive film, not only cost, but also with low layer thickness and can be reliably applied. In the region of their wave peaks 6 and their wave troughs 7, the individual corrugated fins 3 are glued to the respective adjacent tubes 2, wherein the corrugated fins 3 preferably lie flat against the tubes 2 in the region of their wave crests 6 and their wave troughs 7, thereby enabling a good heat transfer.

The corrugated fins 3 according to the invention are preferably formed of aluminum and thus a good heat-conducting material. In theory, a combination of different materials is grateful by gluing the corrugated fins 3 with the tubes 2, so that the corrugated fins 3 can be formed from a different material to the tubes 2, without the risk of contact corrosion exists.

With the corrugated fins 3 formed according to the invention, manufacturing tolerances arising in the assembly of the system 3 and the pipe 2 can be compensated particularly easily, whereby air pockets and higher

Adhesive layer thicknesses, which have an insulating effect and thereby cause a reduced performance of the glued heat exchanger 1, can be avoided. By the bionic embodiment of the bulges 5, an enlargement of the contact surface on the tube 2 can be achieved, whereby a likewise improved heat transfer can be achieved. The embodiment of the corrugated fins 3 shown in FIG. 2 may of course also be formed symmetrically and not as in the example shown asymmetrically. The achievable with the corrugated fin 3 according to the invention spring action can thus compensate comparatively easily even with low layer thicknesses manufacturing tolerances. By the on-block driving of the individual peaks 6 or wave troughs 7 in the corrugated fin 3 according to FIGS. 3 and 4, a particularly stable system can also be created in which an undesirable buckling of the flanks 4 can be reliably avoided.

By gluing the heat exchanger 1 according to the invention, moreover, considerable cost advantages, in particular with regard to resources used and with regard to energy used, in particular with regard to a soldering process, can be achieved, as a result of which a CO2 balance can be markedly improved.

Can be used such a heat exchanger 1, for example, in an internal combustion engine 1 1st

Claims

claims

1 . Heat exchanger (1) with tubes (2) and arranged therebetween

Corrugated ribs (3) with straight flanks (4) and one vault each (5)

having troughs (7) and wave crests (6),

characterized,

- That the vault (5) of a wave crest (6) has a curved first

Section (9) and a linear second portion (10), wherein the second portion (10) is twice as long as the first portion (9) and the first portion (9) and the second portion (10) has an opposite slope of 0.1 to 0.5%, or

- That the vault (5) of a wave crest (6) has a curved first

Section (9) and an equally long and curved in the same direction second portion (10), wherein at unloaded corrugated fins (3) between two adjacent wave crests (6) remains a tolerance distance a, which is dimensioned so that when in the heat exchanger ( 1) built-in state goes to zero and thereby the wave crests (6) rest on block to each other.

2. Heat exchanger according to claim 1,

characterized,

the troughs (7) correspond to inverted wave crests (6).

3. Heat exchanger according to claim 1 or 2,

characterized, an adhesive layer (8), in particular by laminating, is applied to an outer side of the tubes (2).

4. Heat exchanger according to claim 3,

characterized,

the corrugated ribs (3) are glued to the tubes (2) in the region of their wave crests (6) and their wave troughs (7).

5. Heat exchanger according to one of claims 1 to 4,

characterized,

the opposite pitch of the first and second sections (9, 10) is 0.3-0.4%.

6. Heat exchanger according to one of claims 1 to 5,

characterized,

the heat exchanger (1) is designed as an evaporator, as a radiator, as a condenser, as a charge air cooler, as a chiller, as an oil cooler, as a radiator or as a PTC heater.

7. Heat exchanger according to one of the preceding claims,

characterized,

the corrugated ribs (3) are made of aluminum.

8. Heat exchanger according to one of claims 1 to 7,

characterized,

that the corrugated fins (3) in the region of their wave crests (6) and their wave troughs (7) lie flat against the tubes (2).

9. Internal combustion engine (11) with a heat exchanger (1) according to one of claims 1 to 8.

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