EP1331464B1 - Heat exchanger - Google Patents

Abstract

The heat transfer system, between a liquid and a gas and especially for vehicles, has a number of spaced and parallel tubes (2) with ribs (7) between them and each rib has a number of successive and parallel gills (10). Each gill has at least two longitudinal sections (12,13), where two neighboring sections are angled in opposite directions across the longitudinal gill line. All the gills on one rib are arranged so that successive longitudinal sections are angled in the same direction.

Description

The invention relates to a heat exchanger, in particular for a motor vehicle, for heat transfer between a liquid and a gas, having the features of the preamble of claim 1.

Such a heat exchanger is known for example from DE-OS 14 51 216 and has a plurality of tubes which are arranged parallel to each other and spaced from each other. The tubes can be flowed through by the liquid in the tube longitudinal direction and can be flowed around by the gas transversely to the tube longitudinal direction. Between the tubes in each case a plurality of ribs are arranged in the gas flow path, which are heat-transmitting connected to the tubes. These ribs extend with their longitudinal direction transversely to the tube longitudinal direction and at the same time serve as spacers for the tubes. Suitably, all arranged between two adjacent tubes ribs are combined to form a ribbed belt.

Each rib has a plurality of gills which are arranged one behind the other and parallel to one another in the rib longitudinal direction. These gills extend with their longitudinal direction approximately transversely to the tube longitudinal direction and transversely to the rib longitudinal direction. Furthermore, the gills are inclined transversely to the longitudinal direction of the gill against the rib longitudinal direction and thereby When gas is applied to the heat exchanger, the gas flow will flow from one side of the rib to the other side of the rib. Initially, these gills cause a constant rebuilding thermal boundary layers, which are relatively thin on average due to the short start-up lengths and thus allow a relatively good heat transfer between the gas and the gills. The inclination or inclination of the gills causes the inflowing gas is a transverse velocity component in the direction of the tube longitudinal direction is impressed. It comes thereby to a deflection of the gas in the direction of the tube longitudinal direction. This ensures that the gills are not in Totwassergebiet from each other, but can be flowed largely undisturbed by the gas. In order nevertheless to achieve a largely vertical flow direction through the entire heat exchanger, the inclination of the gills, ie the direction of the gill exhibition is reversed approximately in half of the rib length. That is, the gills of each rib are inclined in a first rib longitudinal section in the same direction to each other, while the gills are inclined in a second rib longitudinal section in the same direction and in opposite directions to the gills of the first rib longitudinal section. Furthermore, in all the tube longitudinally juxtaposed ribs in the tube longitudinal direction juxtaposed gills are inclined in the same direction. This design results in a double deflection transversely to the tube longitudinal direction for the gas in the flow through the heat exchanger.

At their longitudinal ends, the tubes are each connected to a container for collecting and / or distributing and / or diverting the liquid. In the vicinity of these containers, the deflection of the gas flow is hindered by the gill angle. As a result, a pressure gradient builds up between the containers, which increases the flow resistance of the heat exchanger. Furthermore, the heat transfer performance of the ribs, starting from a foot soldered to the respective tube, decreases as far as the middle of the rib, whereby a corresponding temperature gradient is formed on the gas side. Since no velocity component in the longitudinal direction of the gill occurs during the flow through the heat exchanger, the central region of the gas flow takes part in the heat transfer in only a small part. In order to improve the fin efficiency, it is possible to reduce the distances between adjacent tubes and thus the gill length or to increase the rib thickness. However, these measures increase the weight and the cost and the gas-side flow resistance of the heat exchanger.

US 6170566 B1 discloses a rib with inlet gills and with outlet gills.

DE 9404009 U1 discloses a heat exchanger with tubes and fins.

The present invention addresses the problem of providing a heat exchanger of the type mentioned an improved embodiment, which in particular achieves a relatively high heat transfer performance at a relatively small pressure loss.

This problem is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea, the gills in such a way that the inclination of the gill transverse direction with respect to the rib longitudinal direction along the gill longitudinal direction reverses at adjacent longitudinal gill segments. The gills thereby show a propeller-like torsion with respect to their longitudinal direction. This means that each gill in the one gill longitudinal section carries the gas flow from the first rib side to the second rib side and in the other gill longitudinal section from the second rib side to the first rib side. With a corresponding arrangement and distribution of these gill longitudinal sections, the cross-flow components of the gas flow can be increased, whereby the heat transfer between gas and gill or rib increases.

According to a particularly advantageous embodiment, all the gills of a rib can be arranged so that the one another in the longitudinal direction of the ribs following gill longitudinal sections are inclined in the same direction. By this measure, the gills following one another in the longitudinal direction of the ribs cooperate in the same direction to deflect the gas flow, as a result of which the flow resistance of the heat exchanger is reduced.

A certain number of juxtaposed in the tube longitudinal direction ribs each form a group of ribs, wherein the ribs of a group of ribs all gills are arranged so that in the tube longitudinal direction of successive gill longitudinal sections are inclined in the same direction, wherein in the ribs of adjacent rib groups, the gill longitudinal sections of a group of ribs in opposite directions the gill longitudinal sections of the other rib group are inclined. By this arrangement, the gill alignment repeats over several ribs and then changes the direction of inclination or twisting direction. After the same number of ribs then the twisting direction or the direction of inclination of the individual longitudinal gill portions is again reversed. The rib groups formed thereby have thus alternating directions of inclination or twisting directions with their gills, which produce a pressure-loss-poor system of counter-rotating vortices. This vortex system leads on the one hand to a gas exchange in the tube longitudinal direction and on the other hand in the longitudinal direction of the gudgeon. This results in an improved turbulence of the gas flow in the central region of the ribs. Overall, this can increase the heat transfer between gas flow and ribs.

For an advantageous development, the number of ribs in the rib groups can be chosen such that the rib groups extend in the tube longitudinal direction approximately as far as adjacent tubes are spaced apart from one another transversely to the tube longitudinal direction. As a result of this design, essentially cylindrical vortices can be generated during the flow through the heat exchanger, which ensures a particularly favorable heat transfer at relatively low pressure losses.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained not only in the particular combination given, but also in other combinations or alone, without departing from the scope of the present invention.

A preferred embodiment of the invention is illustrated in the drawings and will be explained in more detail in the following description, wherein like reference numerals refer to identical or functionally identical or similar components.

Fig. 1

eine Ansicht in Rippenlängsrichtung auf einen Wärmeübertrager nach der Erfindung,

Fig. 2

eine vergrößerte Darstellung eines Ausschnitts II aus Fig. 1,

Fig. 3

eine Schnittansicht der Darstellung aus Fig. 2 entsprechend den Schnittlinien III in Fig. 2,

Fig. 4

eine Ansicht wie in Fig. 2, jedoch einer anderen Ausführungsform,

Fig. 5

eine Ansicht wie in Fig. 3, jedoch entsprechend der Ausführungsform gemäß Fig. 4.

Show, in each case schematically,

Fig. 1

a view in the rib longitudinal direction on a heat exchanger according to the invention,

Fig. 2

an enlarged view of a section II of Fig. 1,

Fig. 3

2 shows a sectional view of the illustration from FIG. 2 corresponding to the sectional lines III in FIG. 2,

Fig. 4

a view as in Fig. 2, but of another embodiment,

Fig. 5

a view as in Fig. 3, but according to the embodiment of FIG. 4th

According to FIG. 1, a heat exchanger 1 has a plurality of tubes 2, which run parallel to one another and are arranged at a distance from one another. The tubes 2 lie in a plane that corresponds to the drawing plane in Fig. 1. The tubes 2 are at their longitudinal ends shown in Fig. 1 below each with a lower container 3 and at its upper longitudinal end shown in Fig. 1 above with an upper container. 4 connected. The tubes 2 are permeable in their interior in their symbolized by a double arrow tube longitudinal direction 5 of a liquid. The containers 3 and 4 serve to collect and / or distribute and / or redirect the liquid flow.

According to a preferred application, the heat exchanger 1 is the heat exchanger 1 of a motor vehicle. For example, it is the so-called "radiator" of the engine cooling circuit or a radiator or a condenser or an evaporator of an air conditioner. In the preferred embodiment shown here, the heat exchanger 1 is a so-called "flat tube heat exchanger", in which the tubes 2 are designed as flat tubes; This means that the tubes 2 are significantly larger transversely to their longitudinal direction 5 in the rib longitudinal direction 8 than in the rib transverse direction 9. The flat tubes can also be constructed by brazed against each other discs, wherein it does not matter here on the internal structure of the discs or tubes 2 ,

Since the tubes 2 are spaced from each other, they are outwardly transversely to the tube longitudinal direction 5 and substantially perpendicular to the heat exchanger plane, that is perpendicular to the plane of the drawing, of a gas, e.g. Air, flow around.

Between adjacent tubes 2 rib ribbons 6 are arranged in the gas flow path, which are corrugated or folded zigzag-shaped, wherein the individual folds or corrugations form ribs 7, which are each connected heat-transmitting with the tubes 2. In particular, the ribs 7 and the ribbed bands 6 are soldered to the tubes 2.

The ribs 7 extend with their in Fig. 3 symbolized by a double arrow longitudinal direction 8 transversely to the tube longitudinal direction 5. The rib longitudinal direction 8 thus extends substantially parallel to the flow of the heat exchanger 1 acting on the gas. The ribs 7 and the rib bands 6 can simultaneously serve as spacers for the tubes 2.

2 and 4, the detail II of Fig. 1 is shown enlarged, the views in FIGS. 2 and 4 are rotated by 90 ° relative to the illustration of FIG. 1. In Figs. 2 and 4, the structure of a special ribbed belt 6 is shown in more detail. In these embodiments, the fold or corrugation of the ribbed belt 6 are designed so that ribs 7, which are arranged in the tube longitudinal direction 5 adjacent to each other, are positioned so that they extend with respect to a transverse to the rib longitudinal direction 8, in Fig. 2 by a double arrow symbolized rib transverse direction 9 parallel to each other. In another embodiment, rib ribbons 6 are corrugated or folded in a zig-zag, as in FIG. 1, so that ribs 7 are inclined with respect to the rib transverse direction 9 and extend only substantially parallel to one another.

According to FIGS. 2 to 5, the ribs 7 each have a plurality of gills 10, which are arranged one behind the other in the rib longitudinal direction 8. A longitudinal direction 11 of the gills 10 extends transversely to the rib longitudinal direction 8 and thus coincides with the rib transverse direction 9. In each rib 7, the gills 10 are arranged with respect to their gill longitudinal direction 11 parallel to each other. Due to the parallel or substantially parallel orientation of the ribs 7, the gills 10 are also arranged with adjacent ribs 7 as shown in FIG. 2, also with respect to their gill longitudinal direction 11 parallel or substantially parallel to each other.

According to the invention, each gill 10 has a plurality of gill longitudinal sections 12 and 13. Two different embodiments are shown by way of example in FIGS. 2 to 5, which differ from one another with respect to the number of gill longitudinal sections 12, 13 per gill 10. In the embodiment of FIGS. 2 and 3, each gill 10 has two longitudinal gill portions 12, 13, while in the embodiment according to FIGS. 4 and 5, each gill 10 has three longitudinal gill portions 12, 13, respectively. The one gill longitudinal sections 12 are shown in Fig. 2 above and drawn in Fig. 3 by solid lines. In contrast, the other gill longitudinal portions 13 are shown in Fig. 2 below and drawn in Fig. 3 with broken lines. 2, the two Kiemenlängsabschnitte 12 and 13 formed substantially the same size, which can be achieved in total a symmetrical deflection effect.

In contrast, in the other embodiment, the one gill longitudinal portions 13 are arranged as shown in FIG. 4 approximately in the middle of the gills 10, while the other two gill longitudinal portions 12 adjoins the outside of the central longitudinal gill portion 13. Accordingly, in Fig. 5, the outer longitudinal gill portions 12 are drawn by solid lines, while the central gill longitudinal portions 13 are plotted with broken lines. According to Fig. 4, the two outer longitudinal gill portions 12 are formed approximately equal. Furthermore, the two outer longitudinal gill portions 12 together are approximately the same size as the central longitudinal gill portion 13th

The gill longitudinal sections 12 and 13 of the gills 10 are wound with respect to the gill longitudinal direction 11 in opposite directions against each other, resulting in a propeller-like twist. As a result of this design, the gill longitudinal sections 12 in each gill 10 which are symbolized in FIG. 3 by corresponding double arrows, transverse to the gill longitudinal direction 11, are inclined relative to the rib longitudinal direction 8. At the same time, the other longitudinal gill segments 13 extend with their transverse direction 14, which is shown in FIG. 3 by dotted double arrows, also inclined to the rib longitudinal direction 8, but the inclination of the other longitudinal gill portions 13 is oriented opposite to the inclination of the gill longitudinal segments 12.

In addition, each gill 10 is arranged at each rib 7 in such a way that the gill longitudinal sections 12 and 13 following one another in the rib longitudinal direction 8 are inclined in the same direction. Referring to Figures 3 and 5, this means that with each rib 7, the upper (see Figure 2) or outer (see Figure 4) gill longitudinal portions 12 are inclined with respect to the rib longitudinal direction 8 in the same manner. Likewise, in the case of each rib 7, all the lower ones (see FIG (see Fig. 4) Gill longitudinal portions 13 in the same manner inclined with respect to the rib longitudinal direction 8. With reference to Fig. 2, this means that the above-illustrated gill portions 12 are inclined within a rib 7 in one direction, while the same rib 7th all shown below second gill longitudinal sections 13 are inclined in the other direction relative to the rib longitudinal direction 8. With reference to Fig. 4, this means that the outboard gill portions 12 are inclined within a rib 7 in one direction, while in the same rib 7, all centrally located gill longitudinal portions 13 are inclined in the other direction opposite to the rib longitudinal direction 8.

In addition, in the embodiments shown here in each case form a certain number of ribs 7, which are arranged side by side in the tube longitudinal direction 5, respectively a rib group 15 and 15 ', which are characterized in Figs. 3 and 5 by braces. It is noteworthy that in the ribs 7 a group of ribs 15 all gills 10 are arranged so that all upper or outer longitudinal gill portions 12 are arranged mutually in the same direction and that all lower or central longitudinal gill segments 13 are oriented in the same direction. This means that in the tube longitudinal direction 5, the successive gill longitudinal sections 12 and 13 are inclined in the same direction. Furthermore, it is noteworthy that in the ribs 7 adjacent rib groups 15 and 15 ', the gill longitudinal sections 12,13 of a group of ribs 15 are inclined in opposite directions to the gill longitudinal sections 12,13 of the other rib group 15'.

By this arrangement, the gill longitudinal sections 12,13 results for the gas flow in the flow through the heat exchanger 1 within the ribs 7, a vortex formation, the helical shape is apparent in particular from FIGS. 2 and 4 and which are designated in Figs , These vortices 16 on the one hand cause a gas exchange in the tube longitudinal direction 5 and on the other hand in the longitudinal direction of the gill 11. By means of this gas exchange, the temperature gradient between regions of the ribs 7 close to the tube and central regions of the ribs 7 remote from the tube can be reduced become. Overall, this improves the heat transfer between gas flow and gills 10 or ribs 7 and thus between gas flow and tubes 5 and the liquid flow guided therein.

In the embodiment according to FIGS. 2 and 3, it is particularly advantageous to choose the number of ribs per rib group 15 or 15 'so that the tube groups 15 and 15' in the tube longitudinal direction 5 extend approximately as far as adjacent tubes 2 transversely to Pipe longitudinal direction 5, ie in the longitudinal direction of the belt 11, are spaced from each other. As a result, the generated vortex 16 can assume a substantially cylindrical shape. This is to achieve small flow resistance of particular advantage.

In the embodiment according to FIGS. 4 and 5, it is particularly expedient to choose the number of ribs per rib group 15 or 15 'such that the tube groups 15 and 15' extend approximately half as far in the tube longitudinal direction 5 as adjacent tubes 2 transversely to the tube longitudinal direction 5, ie in the longitudinal direction of gill 11, are spaced from each other. As a result, as shown in FIG. 4, two contiguous, substantially cylindrical vortices 16 can be produced in each fin group 15, 15 ', which ensure particularly intensive mixing of the gas flow.

In the embodiments shown here, each rib group 15, 15 'has three ribs 7 with co-gills 10 or first longitudinal gill segments 12 and second longitudinal gill segments 13.

The gills 10 form in the ribs 7 breakthroughs, the gills 10 lead due to their employment or inclination at a gas admission of the heat exchanger 1, the gas flow from one side of the rib to the other side of the rib. By opposing flow deflection in the first longitudinal gill segments 12 and the second longitudinal gill segments 13 and due to the selected arrangement and orientation of the gill longitudinal sections 12,13 adjacent ribs 7, the desired vortex 16 can form.

The proposed embodiment of the gills 10 or by the specific orientation of the gill longitudinal sections 12 and 13, propeller-like torsions, which cooperate over several ribs 7 away and there stimulate a self-contained vortex system (Vortex system). This vortex system 16 leads to an intensive gas exchange between tube-near and tube-distant air layers, whereby all layers of air along the gas flow path in the region near the tube with high temperature difference, so that the heat transfer is improved.

In the construction according to the invention, the ribs 7 can build relatively large in the gill longitudinal direction 11, i. the tubes 2 may have relatively large distances from each other. This results in a particularly cost-effective design for the heat exchanger 1. The formation of the vortex 16 has only a comparatively low pressure loss result. Furthermore, the edge regions of the tubes 2, that is to say the transition zones between the containers 3, 4 and the tube longitudinal ends, can also be used better for heat transfer.

Overall, this results in a heat exchanger 1, which allows a very efficient heat transfer between gas and liquid and at the same time produces a relatively low pressure drop for the gas flow.

In the embodiment according to FIGS. 4 and 5, the gills 10 are mirror-symmetrical with respect to a median plane extending in the tube longitudinal direction 5 and in the rib longitudinal direction 8 between the tubes 2. This symmetry may have manufacturing advantages, in particular with regard to distortion during continuous rolling of a ribbed belt 6.

Claims (9)

1. Heat exchanger, in particular for motor vehicles, for exchanging heat between a liquid and a gas,

   - with a plurality of tubes (2),

   -- which are disposed parallel with one another and at a distance apart from one another,

   -- through the interior of which the liquid is able to circulate in the tube longitudinal direction (5),

   -- around the exterior of which gas is able to circulate transversely to the tube longitudinal direction (5),

   - several ribs (7) being disposed respectively between the tubes (2) in the path of the gas flow,

   -- which are connected to the tubes (2) in a heat-transmitting arrangement,

   -- which extend with their longitudinal direction (8) transversely to the tube longitudinal direction (5),

   - each rib (7) having several fins (10),

   -- which are disposed one after the other and parallel with one another in the rib longitudinal direction (8),

   -- which extend with their longitudinal direction essentially transversely to the tube longitudinal direction (5) and transversely to the rib longitudinal direction (8),

   -- which are inclined at an angle with respect to the rib longitudinal direction (8) transversely to the fin longitudinal direction (11),

   -- which direct the gas flow from one rib side to the other rib side when gas is circulating through the heat exchanger (1),

   - each fin (10) having at least two fin longitudinal portions (12, 13),

   - two adjacent fin longitudinal portions (12, 13) being inclined in opposite directions with respect to the rib longitudinal direction (8) transversely to the fin longitudinal direction (11), characterised in that a specific number of adjacently disposed ribs (7) respectively form a rib group (15, 15'), and all fins (10) of the ribs (7) of a rib group (15, 15') are disposed so that the consecutive fin longitudinal portions (12, 13) are inclined in the same direction in the tube longitudinal direction (5), and with respect to the ribs (7) of adjacent rib groups (15, 15'), the fin longitudinal portions (12, 13) of one rib group (15) are inclined in the opposite direction from the fin longitudinal portions (12, 13) of the other rib group (15').
2. Heat exchanger as claimed in claim 1,
   characterised in that
   all the fins (10) of a rib (7) are disposed so that the consecutive fin longitudinal portions (12, 13) in the rib longitudinal direction (8) are inclined in the same direction.
3. Heat exchanger as claimed in claim 1 or 2,
   characterised in that
   the number of ribs in the rib groups (15, 15') is selected so that the rib groups (15, 15') in the tube longitudinal direction (5) are more or less as wide or more or less half as wide in their extension as adjacent tubes (2) are spaced apart from one another transversely to the tube longitudinal direction (5).
4. Heat exchanger as claimed in one of claims 1 to 3,
   characterised in that
   the ribs (7) are disposed parallel with one another by reference to their rib transverse direction (9) extending transversely to the rib longitudinal direction (8).
5. Heat exchanger as claimed in one of claims 1 to 4,
   characterised in that
   in an embodiment in which the fins (10) each have only two fin longitudinal portions (12, 13), the two fin longitudinal portions (12, 13) of every fin (10) are more or less of the same size.
6. Heat exchanger as claimed in one of claims 1 to 5,
   characterised in that
   in an embodiment in which the fins (10) each have more than two fin longitudinal portions (12, 13), the total length of all fin longitudinal portions (12) of every fin (10) oriented in one fin direction is more or less the same as the total length of all the fin longitudinal portions (13) oriented in the other fin direction.
7. Heat exchanger as claimed in one of the preceding claims,
   characterised in that
   in an embodiment in which the fins (10) each have three fin longitudinal portions (12, 13), the middle fin longitudinal portion (13) of every fin (10) is more or less the same size as the two outer, approximately same-sized fin longitudinal portions (12) together.
8. Heat exchanger as claimed in one of claims 1 to 7,
   characterised in that
   all the ribs (7) disposed between two adjacent tubes (2) are grouped in an essentially zigzag-shaped corrugated or pleated rib strip (6).
9. Heat exchanger as claimed in one of claims 1 to 8,
   characterised in that
   the heat exchanger (1) is of a flat tube heat exchanger design, in which the direction of extension of the tubes (2) in the rib longitudinal direction (8) extending transversely to the tube longitudinal direction (5) is bigger than it is transversely thereto.

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