EP2161528A2 - Flow guiding element and heat exchanger - Google Patents

Abstract

The element (50) has a laminar base plane (52) extending in a main flow longitudinal direction (3), and limiting structures (57) for forming and lateral limiting of number of flow paths (59). The flow path exhibits an upstream flow distance between the limiting structures laterally assigned to the flow path, and a downstream flow distance between the lateral limiting structures for influencing flow guidance in the longitudinal direction, where the distances are different from each other. The flow paths are arranged on a lateral extension between the limiting structures. An independent claim is also included for a heat exchanger for exchanging heat between the fluids.

Description

The invention relates to a flow guide for arrangement in a heat exchanger to a heat exchange influencing flow guidance of a fluid along a main flow longitudinal direction of a fluid inlet to a fluid outlet. The invention further relates to a heat exchanger for heat exchange between a first fluid and a second fluid.

In a heat exchanger for heat exchange between a first fluid, for example an exhaust gas or a charge air, and a second fluid, for example a coolant, a heat exchange between the first and second fluid is implemented in increasingly narrow space. For this purpose, a heat exchanger usually has a block arranged in a housing for separate and heat exchanging guidance of the first fluid and the second fluid along a main flow longitudinal direction from a fluid inlet to a fluid outlet.

Thereby, for example, in an exhaust gas heat exchanger for cooling exhaust gas, an exhaust gas at up to 750 ° C are cooled with an engine coolant. It has been found that, especially in areas of entry of the first fluid into the heat exchanger, the temperature differences between the first fluid and the second fluid are comparatively large. Overall, it is desirable, for example in areas such as the aforementioned inlet area, to make cooling or heat exchange between the first and second fluid particularly effective.

For this purpose, it is known to provide a flow guide for at least one of the fluids, in particular for the second fluid, for influencing the heat exchange between the fluids. In principle, a flow-guiding element can be understood as any element influencing the flow of a fluid, for example also a turbulence sheet, as described in the Applicant's application under the file number of the applicant 05-B-186.

Such or other flow guide can be used as individual parts in a flow channel, for. As a flat tube, are used and soldered to this, or even be an integral part of a pipe or a disc. For example, this is off DE 29622191 U1 a plate heat exchanger known, in which between the discs turbulence plates of the aforementioned type are arranged. Formations of integral internal ribs with flat tube go from the publications EP 1 281 923 A2 . US 2757628 A . FR 2769359 A and EP 0 646 231 B out. For example, this is off DE 10242188 A1 the applicant a flat-tube heat exchanger with a brazed tube / rib system known, the tubes are preferably flowed through by a liquid medium and the ribs, preferably by air.

Although such turbulence-generating flow directors have been shown to be advantageous in promoting heat exchange, it has been found that there is an increased need for particularly high levels of heat exchange, particularly in view of decreasing space availability and increasing temperature differences between the first and second fluids Heat exchange rates exists and a support of the heat exchange beyond the generation of turbulence is desirable.

At this point, the invention begins, whose task is to provide a device, in particular a flow guide and / or a heat exchanger, by means of a heat exchange between the first fluid and the second fluid can be made particularly effective, in particular the flow guidance of a fluid can be advantageously influenced.

Regarding the flow guide, the object is achieved by the invention with a flow guide of the type mentioned, in which according to the invention a extending in the main flow longitudinal planar ground plane is provided, over the ground plane at least partially lateral boundary structures to form and at least partially lateral boundary of a number of flow paths, and for influencing the flow guidance in the main flow longitudinal direction, at least one flow path has an upstream first distance between two lateral boundary structures associated with the flow path and a downstream second distance of the lateral boundary structures, the distances being different. The spacing of the distances is preferably such that a pressure loss of the fluid associated with the flow path from a first location associated with the upstream first distance to a second location associated with the downstream second distance is different than a pressure loss of an imaginary flow path with substantially equal is spaced boundary structures.

The invention is based on the consideration that a turbulence sheet, as is known from the prior art, or other flow guide elements, for example in the form of a coolant rib o. The like. Usually not designed, a comparatively homogeneous fluid distribution or the temperature distributions in Heat exchanger to support adequate distribution of a fluid. On the contrary, it has been found that conventional flow guide elements, in a manner still to be improved, permit comparatively excessively much fluid flow on a direct path between fluid inlet and fluid outlet. The invention is based on the consideration that, however - especially in the region of a fluid inlet, preferably also in the region of a fluid outlet - there are comparatively critical points in the heat exchanger. Such critical points should be due to their temperature distribution - namely in particular a comparatively high temperature difference between the first fluid, eg exhaust gas, and second fluid, e.g. B. coolant - particularly preferably with a heat exchange - supporting fluid to be acted upon. Conversely, according to the consideration of the invention, an excessive flow flow should be suppressed directly from the fluid inlet to the fluid outlet in favor of such aforementioned areas, ie, a direct flow path less strongly flowed with a fluid. Overall, the concept of the invention has recognized that it is possible with the flow guide element proposed according to the invention to distribute a fluid, in particular a second fluid, preferably in the form of coolant, as needed in accordance with a heat distribution in a heat exchanger.

This concept becomes particularly clear by means of an exemplary in Fig. 4 illustrated embodiment of a heat flow demand distribution. It has been found that, for example, coolant should be distributed as homogeneously as possible over a heat exchanger cross section at the inlet, so that no dead zones occur in which there is a lack of coolant. This danger exists in particular in areas with high heat flow densities, namely fluid inlet, for example, on the exhaust gas or charge air inlet, in which a good heat transfer should be ensured on the coolant side. In dead zones, there is a risk that the fluid will start to boil and the heat transfer on the coolant side will be severely reduced by the formation of steam, resulting in local overheating, high thermal stresses and possibly cracks in the material. In addition, disadvantageous high wall temperatures and high thermal expansions are the result of often, especially at the gas inlet, insufficient coolant supply.

Based on this consideration, the concept of the invention proposes a flow-guiding element in which, in brief, a pressure-adapted flow guide is provided with the number of flow paths with which it is possible, in particular a second fluid, for example in the form of a coolant, reinforced in one area to supply a high heat flux density and in other cases, in particular a second fluid, areas zuzuleiten with lower heat flux density to a lesser extent. In this case, the invention has recognized that a pressure loss of a fluid in a flow path is significantly influenced by the distance of lateral boundary structures. This is particularly true for relatively flat flow paths. However, the concept of the invention, of course, encompasses embodiments in which, for influencing the flow guidance in the main flow longitudinal direction, the at least one flow path has an upstream first cross section of all limiting structures and a downstream second cross section of all delimiting structures, the cross sections being different. In other words, the concept of the invention has recognized in the present case that, with suitable cross-sectional adaptation of a flow path, a fluid flow, in particular a coolant flow, can be designed concretely in a heat exchanger with regard to a specific heat flow density.

Advantageous developments of the invention can be found in the dependent claims and specify in detail advantageous ways to realize the above-described concept within the scope of the task, as well as with regard to further advantages.

It has been found in the course of investigations that a number of at least three, preferably at least four, flow paths is particularly advantageous for guiding the flow in a flow guide for a conventional heat exchanger. In particular, it has been found that five or more flow paths are advantageous for a particularly good flow guidance. In the drawing, particularly preferred embodiments are described in which the flow guide in a particularly preferred manner has six or seven flow paths.

With regard to the arrangement of the number of flow paths, it has been found that these are advantageously adjacent to one another on a lateral extent-designated in the further course of the application as Δy _EA -between two outer, lateral boundary structures of the flow guide arrange to be ordered. For example, assuming a substantially rectangular configuration of the flow-guiding element, the lateral extent Δy _EA would correspond essentially to somewhat less than the width of the flow-guiding element. It has been shown that a particularly advantageous heat dissipation can be achieved, especially in the area of the fluid inlet and the fluid outlet, in particular as described in detail below.

With regard to the arrangement of the number of flow paths to each other, various criteria, which can be selected advantageously depending on the intended use, can be specified. Thus, at least one first flow path or at least one first group of flow paths-for example flow paths P1, P2-provided in the exemplary embodiments and at least one second flow path or a second group of flow paths-in the exemplary embodiments, for example, the flow paths P3 to P7 or P2 to P7 are provided, which differ in training and arrangement. With regard to the lateral extent of the flow-guiding element, a first flow path is preferably arranged laterally outside a second flow path with regard to the relative arrangement on the flow-guiding element. Conversely, with regard to the lateral extension of the flow-guiding element, a second flow path is arranged laterally inwardly next to a first flow path. In other words, the first group of flow paths lies substantially in the outer regions of the lateral extension of the flow guide, while the second group of flow paths are located in the inner regions of the lateral extension flow guide elements. In a particularly preferred manner, at least one first flow path or a first group of flow paths and at least one second flow path or a second group of flow paths is provided, wherein a first flow path of an outer, lateral boundary structure is arranged closer than a second flow path. Conversely, a second flow path is closer to a fluid inlet or outlet than a first flow path.

It has also been shown that - as will be explained in more detail below - a first flow path or a first group of flow paths on the one hand and a second flow path or a group of second flow paths on the other hand can also be interpreted differently with respect to their course in order With regard to their arrangement with respect to the lateral extent of the flow guide, to achieve a particularly preferred flow guidance.

In general, it should be noted that with regard to the flow guidance, the at least partially lateral limiting structures are such that a flow cross-exchange is not completely released. In other words, it has been found according to this development of the invention that a continuous lateral boundary structure, although possible and useful, is by no means imperative for achieving the inventive concept. Rather, it can prove to be advantageous for flow guidance and also for production reasons expedient to provide a limiting structure such that a lateral boundary of a flow path through the limiting structure only partially, i. e.g. sections, is given while there are openings between sections, which in principle allow a flow cross-exchange.

In particular, the at least one flow path may have a, preferably continuously changing distance of the lateral boundary structures. In a particularly preferred development, a variable ratio of coolant inlet surface to coolant outlet surface can be realized for a flow path. For example, the ratio of a coolant inlet surface to a coolant outlet surface may be greater than "1" - in this case, it is a flow path, which realizes a comparatively high flow velocity and thus a comparatively high pressure loss in downstream regions, so that such a flow path is suitable to make a fluid flow comparatively small. In principle, in the extreme case, such a flow path can also be completely blocked, for example by a flow path extremely narrowing web arrangement or the like. Such or similar, clearly and for the sake of simplicity referred to as "block path" flow path is suitable in a preferred manner in areas where a comparatively lower fluid requirement, in particular coolant requirement exists. These are, for example, areas on or in the vicinity of a direct connection between fluid inlet and fluid outlet. As previously explained, in the neutral design of a flow guide, there is an excessive amount of fluid, in particular coolant, such that flow guidance in such regions can be influenced by the arrangement of a "block path" such that less fluid compared to a neutral design the flow guide is supplied.

In an opposite situation, an upstream cross section may be less than a downstream cross section of the flow path. Such a flow path is accordingly designed to have a comparatively lower pressure loss compared to an imaginary flow path with substantially equally spaced boundary structures, i. a neutral flow path design. Such a flow path is thus suitable for carrying comparatively more fluid, in particular coolant, in comparison to a neutral flow guidance design. Such a flow path is clearly and for the sake of simplicity referred to as "suction path". The arrangement of a suction path has proven to be particularly advantageous in areas of a heat exchanger, which are comparatively far away from a direct connection between a fluid inlet and a fluid outlet.

Overall, a particularly preferred development of the invention provides for a flow guide a plurality of flow paths, wherein in particular a first and a second flow path is provided, wherein from an upstream first point to a downstream second location along the main flow longitudinal direction of the first flow path longer than the second flow path is. The invention has recognized that such flow paths due to different pressure losses have different lengths and thus a different need for second fluid can be effected in such flow paths.

In particular, a first flow path may have an upstream first distance of the lateral boundary structures and a downstream second distance of the lateral boundary structures, wherein the first distance is less than the second distance. This is a previously discussed block path.

In particular, a second flow path may have an upstream first distance of the lateral boundary structures and a downstream second distance of the lateral boundary structures, wherein the first distance is greater than the second distance. Such a flow path is a previously discussed suction path.

Preferably, the distance ratio between the first and the second distance is higher in a "block path" than in a "suction path".

Advantageously, the second flow path is arranged to extend substantially in the main flow longitudinal direction. Particularly advantageously, the second flow path can extend comparatively directly, in particular longitudinally, or run in a diametrically oriented manner relative to the flat ground plane of the flow guidance element, from a fluid inlet to a fluid outlet. Preferably, it has virtually no or only slightly transverse regions. A second flow path or a group of second flow paths thus advantageously has practically only (one or more) longitudinal regions extending essentially in the main flow longitudinal direction and virtually no transverse region.

Particularly preferably, the first flow path may extend at least regionally transverse to the main flow longitudinal direction. This has the advantage that the first flow path is additionally suitable - this at comparatively Reduced pressure drop - areas of a heat exchanger with fluid, in particular to supply coolant, which have in view of an expected heat flow density comparatively insufficient coolant in the case of a neutral design. This concerns in particular areas of a fluid inlet and / or a fluid outlet. For example, the first flow path may be oriented comparatively indirectly, in particular circumferentially close to the planar ground plane, from a fluid inlet to a fluid outlet. A first flow path or a group of first flow paths thus advantageously has-in particular, apart from one or more longitudinal regions-also at least one transverse region extending essentially transversely to the main flow direction.

As explained above, a main flow direction is essentially defined by the direction between the fluid inlet and the fluid outlet on the flow element.

Overall, the development of the invention provides that the first flow path is designed to carry an increased fluid flow rate - compared to a first flow path in an otherwise identical imaginary flow path arrangement having a first and second flow path with substantially equally spaced boundary structures. Conversely, this applies to the second flow path. In other words, the flow guide is designed so that in flow paths, in which due to the expected heat flow densities comparatively much second fluid is required - referred to here as the first flow path - a low pressure loss is generated, while in flow paths in which comparatively little coolant in Considering the expected heat flow densities is needed - here referred to as the second flow path - a comparatively higher pressure loss is generated.

In addition to the described measures with regard to a flow path cross-section, blocking measures or further other or similar generally throttling flow-guiding measures can be provided, in particular in the case of second flow paths. A blockage can be realized for example by introducing porous media, perforated plates or the like. As a flow guide also embossments, beads or punched can be provided. A delimiting structure can in particular be designed as a rib or web. Particularly in the case of first flow paths, flow line-promoting measures can be additionally provided. Thus, in particular in corner regions of the flow-guiding element, deflecting plates can be arranged on the ground plane in order to better conduct a flow.

Moreover, within the scope of a particularly preferred development of the invention, it has proven to be advantageous for a ratio of distances (cross sections) of the delimiting structures, and / or a changing ratio of a downstream distance (cross section) of the delimiting structures, to change from flow path to flow path an upstream distance (cross section) of the boundary structures, is provided. In particular, such variable ratio of cross-sections from flow path to flow path may decrease and / or in a direction from a fluid entry point to a fluid exit point. In other words, the ratio decreases advantageously, in particular for second flow paths, or increases advantageously, in particular for first flow paths, the farther a flow path is away from a direct connection between the coolant inlet and the coolant outlet. This is advantageous for directly opposite fluid inlet and outlet along a longitudinal extent, as well as opposite to a diagonal of the ground plane Kühlmittelein- and exits.

According to a further development, the flow-guiding element has, in particular, a first and a second part, the first and second part being provided with limiting structures extending essentially mirror-symmetrically.

The concept of the listed below and in detail the further subclaims 16 to 25 particularly preferred developments The invention results from an optimization calculation for a flow guide, in particular coolant guide plate, which in the detailed description of Fig. 5 to Fig. 8 basically explained:

It follows that, in a particularly advantageous embodiment, the flow guide element can generally identify a first part and a second part, which differ structurally clearly from a center part listed below. In this case, the first part should be assigned to the fluid inlet and the second part should be assigned to the fluid outlet, ie in particular be directly adjacent to the fluid inlet or fluid outlet. In particular, it is provided that the number of flow paths in the main flow longitudinal direction each extend at least to a longitudinal path length L _path within the first part and / or second part. It has proven to be particularly expedient for determining a path length that the path length L _{path of} at least one flow _path - preferably of all flow paths - is greater than a lateral extent Δy _EA between two outer, lateral boundary structures of the flow guide. In other words, a path length L _path should be substantially longer than the width of the flow guide. It has been found that, under this condition, a suitably advantageous orientation of the flow in the longitudinal direction of the flow-guiding element can already be achieved - this also on condition that the lateral limiting structures only partially limit a flow path. In particular, it is advantageously provided for this purpose that a path length is at least that length of a flow path along which the flow path is bounded uninterruptedly by the lateral limiting structures assigned to it.

Taking into account the above-mentioned optimization calculation for a flow guide element according to the particularly preferred development of the invention, advantageous parameters identified for the optimization calculation can be given quantitatively for the design of the delimiting structures which are claimed in more detail in the further subclaims 21 to 24 and are described below - advantageous embodiments thereof are in the Fig. 5 to Fig. 8 explained.

In particular, it is provided that, in the case of at least one first flow path, the first distance and the second distance of the lateral limiting structures assigned to it are such that a relative velocity v _rel in the at least one first flow path is greater than one. Preferably, a relative velocity v _rel - according to formula (3) - should be greater than 1.1, preferably greater than 1.15. It has proven to be particularly preferable for the first distance and the second distance of the lateral limiting structures assigned to it to be closest to an outer, lateral boundary structure and initially adjacent thereto, such that a relative velocity v _rel - according to formula (3) - Is greater than 1.12 in both first flow paths. Surprisingly, it has been shown that even this amount of a relative speed sufficiently supports a heat dissipation which prefers the lateral extent.

According to a second aspect of the optimization calculation, it has been found that in particular a width ratio of a distance b _Q in a transverse region to a distance b _L in a longitudinal region - according to formula (4) - is less than a width ratio of a distance b for at least one of the first flow paths _Q in a transverse region to a distance b _L in a longitudinal region for at least one of the second flow paths - according to formula (4). In particular, it has proved to be particularly advantageous that - according to formula (5) - a ratio of the widths of the formula (5) follows, where n specifies a path number belonging to the second group of paths. Expediently, the constant c should be greater than 2, in particular greater than 5, preferably greater than 10.

According to a third aspect of the optimization calculation, it has been shown that it is particularly advantageous for one of the second flow paths, preferably at least one fluid inlet or outlet, to be arranged next to the second flow path, in particular the flow path the highest number, to throttle. For this purpose, this flow path of the second group of flow paths, in particular that with the highest number, at least partially blocked. In particular for the above-mentioned or directly adjacent flow paths of the second group, it is preferable that a width ratio of a distance b _Q in a transverse range to a distance b _L in a longitudinal range approaches infinity - in other words, the distance b _L in a longitudinal range approaches 0. Practically this means that the said width ratio - according to formula (4) - for at least one of the second fluid paths, preferably at least one fluid inlet or fluid outlet nearest second flow path is particularly large, preferably above 10, in particular above 100 is, in particular above 1000 lies.

As explained above, this quantitative specification of relative velocities v _rel, width ratios b _Q / b _L and throttle parameters, which is recognized in the abovementioned optimization calculation, applies in particular to the first flow paths-in the embodiments in particular flow paths P1, P2-and second flow paths-in the embodiments in particular flow paths P5, P6, P7 - which in a first / second part, ie the fluid inlet / fluid outlet first surrounding area, the flow guide are arranged.

Preferably, a middle part is arranged between the above-mentioned first and second part. In particular, the middle part can have undulating strips formed from the ground plane, which are arranged in rows in the main flow longitudinal direction. Preferably, adjacent rows are arranged offset from each other transversely to the main flow longitudinal direction. In particular, in each case trailing edges and leading edges are provided, which limit the passage opening in the main flow longitudinal direction. Such, advantageously designed as turbulence middle part can thus in a particularly preferred manner described in connection with a turbulence sheet turbulence structures, as described in the applicant's application with the applicant-side file reference 05 B 186, which is hereby incorporated by reference into the disclosure of the present application.

• einen in einem Gehäuse angeordneten Block zur voneinander getrennten und wärmetauschenden Führung des ersten Fluids und des zweiten Fluids entlang einer Hauptströmungslängsrichtung von einem Fluideintritt zu einem Fluidaustritt, wobei zu einer den Wärmetausch beeinflussenden Strömungsführung eines der Fluids, insbesondere des zweiten Fluids, ein Strömungsleitelement gemäß dem Konzept der Erfindung vorgesehen ist.

With regard to the heat exchanger, the invention leads to a heat exchanger of the type mentioned, which has:

• a block arranged in a housing for the separate and heat exchanging guidance of the first fluid and the second fluid along a main flow longitudinal direction from a fluid inlet to a fluid outlet, wherein a fluid flow element influencing the heat exchange of one of the fluids, in particular of the second fluid, according to the concept the invention is provided.

Advantageous developments of the heat exchanger can be found in the dependent claims and specify in particular advantageous ways to realize the above-mentioned concept within the scope of the task, as seen visibly further advantages.

In particular, the first fluid may be provided for the delivery of heat to the second fluid. In particular, the first fluid may be a charge air or an exhaust gas and / or the second fluid may be a coolant. In a particularly preferred manner, the flow-guiding element can be arranged in a flow channel of the block and / or between flow channels in the housing. In other words, the flow guide according to the concept of the invention is basically designed for heat exchange-influencing flow guidance of a first fluid as well as a second fluid, wherein it is naturally preferred that the flow guide to flow influencing the second fluid, preferably in the form of a coolant, is provided , Additionally and optionally alternatively, in a modified development, the flow-guiding element can also be provided for influencing the flow of the first fluid, preferably an exhaust gas and / or a charge air. Accordingly, it has proved to be advantageous to arrange the flow guide as needed and purpose in a flow channel of the block and / or between flow channels in the housing, depending on how a first and / or second fluid is guided in the heat exchanger.

In a particularly preferred first variant of the development, a flow channel in the form of two interconnected flat, in particular largely flat or curved plates may be formed. It has proved to be particularly advantageous that the flow guide is arranged between the plates. In particular, it has proved to be advantageous for the plates and the flow guide element to form a prefabricated second flow channel for conducting the second fluid.

According to a second, likewise preferred variant of the invention, it has proved to be advantageous to form a flow channel in the form of a tube, and to arrange the flow guide between the flow channels, in particular between two rows of tubes, for the conduction of the second fluid.

A heat exchanger is preferably designed in the form of an exhaust gas heat exchanger and / or a charge air heat exchanger.

While the invention is particularly useful for the use of the flow guide for guiding a second fluid, in particular coolant proves and is to be understood in this sense and while the invention is described below in detail with reference to examples of a flow guide for influencing the flow of a coolant, so It should be understood, however, that the concept described herein, as claimed, is also useful in the context of other applications that are outside of the flow control for a coolant in the strict sense. For example, the concept presented above, as already partially explained above, could also be used for influencing the flow of a first fluid, in particular a hot fluid, for example an exhaust gas and / or a charge air. Further examples relate to the use of the flow guide, for example in an oil cooler or refrigerant radiator or refrigerant condenser - in addition to one Flow control function for a coolant, a flow guide according to the concept of the invention may also be provided for the flow line for an oil or the refrigerant in an expedient manner. The flow guide can be used in Wärmetausehern and flow channels in a variety of forms. Plate or disc channels or channels in or outside of tubes are exemplified.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article that would be limited in comparison with the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable.

Fig. 1

eine besonders bevorzugte Ausführungsform eines Wärmetauschers gemäß dem Konzept der Erfindung in Form eines Plattenwärmetauschers;

Fig. 2

eine Explosionsdarstellung eines Strömungskanals bei einem Plattenwärmetauscher der Fig. 1, welcher Strömungskanal in Form von zwei miteinander verbundenen Flächen plattengebildet ist, die im Zwischenraum ein Strömungsleitelement aufnehmen zur Strömungsführung eines Kühlmittels;

Fig. 3

eine Explosionsdarstellung der Ausführungsform eines anderen Wärmetauschers mit einem Doppelströmungskanal oder einer Mehrzahl von Strömungskanälen ähnlich dem in Fig. 2;

Fig. 4

eine schematische Ansicht einer Wärmestrombedarf-Simulation unter Berücksichtigung eines bestimmten Wärmeeintrags in einen Kühlmittelkanal bei einem Wärmetauscher der Fig. 1 bis Fig. 3;

Fig. 5

eine besonders bevorzugte Ausführungsform eines Strömungsleitelements, wie es zur Einbringung in einen Strömungskanal-beispielsweise gemäß Fig. 2 oder Fig. 3 - vorgesehen ist;

Fig. 6

eine Darstellung der Kühlmittelverteilung in einem ersten Teil des Strömungsleitelements in Nachbarschaft zu einem Kühlmitteleintritt der Fig. 5;

Fig. 7

eine schematische Darstellung einer abgewandelten Ausführungsform des ersten Teils eines Strömungsleitelements ähnlich dem in Fig. 6;

Fig. 8

eine weitere abgewandelte Ausführungsform eines ersten Teils eines Strömungsleitelements ähnlich dem in Fig. 6.

In detail, the drawing shows in:

Fig. 1

a particularly preferred embodiment of a heat exchanger according to the concept of the invention in the form of a plate heat exchanger;

Fig. 2

an exploded view of a flow channel in a plate heat exchanger of Fig. 1 which flow channel is plate-shaped in the form of two interconnected surfaces, which receive in the intermediate space a flow guide for guiding the flow of a coolant;

Fig. 3

an exploded view of the embodiment of another heat exchanger with a double flow channel or a plurality of flow channels similar to that in Fig. 2 ;

Fig. 4

a schematic view of a heat flow demand simulation taking into account a specific heat input into a coolant channel in a heat exchanger of Fig. 1 to Fig. 3 ;

Fig. 5

a particularly preferred embodiment of a flow guide, as for introduction into a flow channel-for example according to Fig. 2 or Fig. 3 - is provided;

Fig. 6

a representation of the coolant distribution in a first part of the flow guide in the vicinity of a coolant inlet of Fig. 5 ;

Fig. 7

a schematic representation of a modified embodiment of the first part of a flow guide similar to that in Fig. 6 ;

Fig. 8

a further modified embodiment of a first part of a flow guide similar to that in Fig. 6 ,

Fig. 1 shows a heat exchanger 10 according to a particularly preferred embodiment of the invention in the form of a so-called "disc heat exchanger". The heat exchanger 10 has a housing 11 in a arranged block 13 for the separate and heat exchanging guidance of the first fluid 1 in the form of an exhaust gas and the second fluid 2.1 and 2.2 in the form of a coolant along a main flow longitudinal direction 3 from a fluid inlet opening 5.1, 6.1 to a fluid outlet opening 5.2, 6.2. In the present case, the heat exchanger 10 is provided in the form of a two-stage heat exchanger with a high-temperature stage 10.1 and a low-temperature stage 10.2, wherein correspondingly the high-temperature stage 10.1 is flown for cooling with a high-temperature coolant 2.1 via a fluid inlet opening 5.1 and a fluid outlet opening 5.2 and the low-temperature stage 10.2 with a low-temperature coolant 2.2 on a fluid inlet opening 6.1 and a fluid outlet opening 6.2 is flowed. As the coolant, a water-based coolant is presently provided, wherein the temperature of the high-temperature coolant 2.1 is above that of the low-temperature coolant 2.2.

The block 13 of the plate heat exchanger has a number of flowable through with coolant 2.1, 2.2 flow channels 20, which in Fig. 2 and Fig. 3 the example of a single-stage heat exchanger 10 'shown in exploded view are exemplified. A flow channel 20 is presently formed in the form of two interconnected flat plates 21.1, 21.2, so that the coolant is a gap 23 to the flow available. According to Fig. 3 a modified flow channel 20 'may also be formed by means of three plates 21.1, 21.2, 21.3, wherein the flow channel 20' then a double channel with two spaces available to the coolant 23 is formed - if necessary, the entire block is formed in this stack shape , In the intermediate space 23, in the present case, a flow-guiding element 50 is arranged, as shown in FIG Fig. 5 is shown in more detail. A flow channel 20 or a flow channel 20 'is presently provided with a flow guide element 50 arranged in the intermediate space 23 as a prefabricated flow channel 20, 20' for assembly in the block 13 of a heat exchanger 10 or 10 '. The block 13 is arranged in the assembly in a housing 11 of the heat exchanger 10, 10 'so that a along the main flow longitudinal direction 3 and discharged longitudinal flow of the exhaust gas between the Fig. 1 apparent Gaps 25 between the flow channels 20, 20 'is possible. For this purpose, the exhaust gas is supplied and discharged via a box fixed to the housing 11, for example in the case of the heat exchanger 10 'in the form of an inlet diffuser 7.1 and outlet diffuser 7.2.

The coolant 2 is the single-stage heat exchanger 10 'of Fig. 3 via an insertion 4.1 a fluid inlet 24.1 of the flow channel 20 'is supplied and discharged via a discharge pipe 4.2 of a fluid outlet 24.2 of the flow channel 20'. The multiply arranged flow channels 20 'of the in Fig. 3 shown heat exchanger 10 'are in the Fig. 3 apparent explosive representation with each other fluidly connected such that the coolant 2 via the insertion of 4.1 each of the fluid ports 24.1 forwarded and after passing through the gap 23 of the flow channel 20 'again on the plurality of fluid outlets 24.2 the discharge pipe 4.2 of the heat exchanger 10' is supplied. The feed pipe 4.1 and the discharge pipe 4.2 is presently mounted on a housing cover 12 or otherwise attached. In this way, on the one hand, a guidance of the coolant 2 takes place in the closed coolant circuit formed by the flow channels 20 '. On the other hand, the flow channels 20 'in a block 13 laterally, in the flow longitudinal direction 3, of fluid 1 in the form of hot exhaust gas can flow.

A resulting heat distribution 40 is basically represented in the half model as a top view for a flow channel 20, 20 'due to a heat input 41 caused by the exhaust gas 1. The heat input 41 is effected by the exhaust gas 1 guided in the main flow longitudinal direction 3 above and below the coolant channel 20, 20 '. A coolant inlet 24.1 is made comparatively large in cross section in order to keep pressure losses during the inflow from the coolant connection 4.1 into the disk bundle forming the flow channel 20, 20 'low. This leads to a comparatively low flow velocity, which in turn results in a comparatively low transverse distribution pressure loss at the coolant inlet. In addition, the illustration shows the Fig. 4 in that a highest heat input is present on the side of the entrance of the fluid 1 and therefore on the with Longitudinal extension "a" designated inflow a particularly high heat dissipation performance is needed. The invention recognizes that not only the coolant speed should be comparatively high, but also the availability or the coolant quantity-especially in lateral areas "s", especially in the area of a leading edge "v" -that is particularly high in the inflow area should be that a boiling coolant is avoided. Of course, this also applies to the central region "z" at the leading edge "v" of the flow channel 20, 20 ', of which, however, is usually not expected that there - in the immediate vicinity of the fluid inlet 24.1 - a lack of coolant, which is an essential Difference to the side areas "s" represents. In addition, a side of the coolant inlet 24.1 lying region of the extension "m" proves problematic because - as recognized by the concept of the invention - a coolant tends from the coolant inlet 24.1 largely centrally in the main flow longitudinal direction 3 to the coolant outlet, ie in the direction of greatest pressure loss to stream. The concept of the invention is not limited to the geometry shown here of a coolant inlet 24.1 centered in the flow channel, but also includes, for example, entrances or other geometries arranged geometrically close to a diagonal of the flow channel, which are not shown here.

Recognizing this, the concept of the invention leads to a particularly preferred embodiment of a flow-guiding element 50, as shown in FIG Fig. 5 is shown by way of example. The flow guide 50 has a first, the fluid - ie here coolant inlet 24.1 associated, substantially the expansion "a" corresponding inflow, which is also referred to as the first part 51.1 and a mirror-symmetrical arranged and otherwise identical to a discharge area around the fluid Outlet - ie here coolant outlet 24.2, arranged outlet part, which is also referred to as the second part 51.2, on. Between the inlet part 51.1 and the outlet part 51.2, a middle part 51.3 is arranged, which is characterized by adjacent channels 55 which are connected to one another and are formed by rib ribs 53. Overall, the webs 53 are part of wavy formed from a ground plane 52 strips formed, which are arranged in main flow longitudinal direction 3 in rows one behind the other. In this case, adjacent rows 56.1, 56.2 are arranged offset from one another transversely to the main flow longitudinal direction 3 and each have trailing edges and leading edges which delimit passages 55 in the main flow longitudinal direction 3. Overall, this middle part 51.3 can also be used to form a turbulence generating part, for example by using an additional or alternative structure for generating a turbulence or another Strömungsleitfunktion as described in the applicant's earlier application under the file number of the applicant 05-B-186 and the disclosure of which is hereby fully incorporated by reference into the disclosure part of the present application.

The present as deep-drawn available flow guide 50 provides to remedy the basis of Fig. 4 explained problematic in the inflow 51.1 in the main flow longitudinal direction 3 extending planar ground plane 52, wherein over the ground plane 52 side limiting structures 57 to form a number of - Fig. 6 in the present case, six different flow paths 59, each mutually on a top 61 and bottom 63 of the flow guide 50, raise. For influencing the flow guidance in the main flow longitudinal direction 3 of the coolant, a flow path 59 has an upstream first distance (cross section) - more clearly eg in FIG FIGS. 7 and 8 the further _embodiments shown as A - of the lateral boundary structures and a downstream second distance (cross-section) of the lateral boundary structures - for example, more clearly in FIGS. 7 and 8 of further embodiments shown as A _from - on. Such cross sections P1.1 to P6.1 as upstream cross sections are also in Fig. 6 indicated - corresponding cross sections P1.2 to P4.2 or P1.3 to P3.3 as downstream cross sections are also in Fig. 6 indicated. In the present case, the distances at a flow channel 59 change continuously. Thereby, a pressure loss of the coolant associated with the flow path from a location associated with the upstream first distance (there P1.1 to P6.1) becomes a formed downstream of the second distance (eg there P1.2 to P4.2 or P1.3 to P3.3) designed differently than a pressure drop of an otherwise equal run flow path with substantially equally spaced boundary structures. In the present case, this measure takes place in order to provide a quantity of coolant which is appropriate for the heat input 41 and, despite the different length of the flow paths 59, nevertheless provides a balanced pressure loss for each path. As a result, each path is supplied with a sufficient amount of coolant as a result of the overall pressure conditions for all the paths competing for coolant.

In detail is according to Fig. 6 the effect achieved by the present structure can be seen as follows. In principle, the static pressure loss in all paths 59 is approximately the same due to the static pressure loss Δp prevailing between the coolant inlet 24.1 and the coolant outlet 24.2. As based on Fig. 4 1, a particularly high coolant velocity is required at the leading edge 65 of the coolant channel identified by arrows - this applies in the present case above all to the first group of flow paths provided with numbering P1 and P2 and especially strongly for the number P1 numbered flow path. Such flow paths - also referred to herein as "edge path" or "suction path" - are relatively longer relative to the further inward second group of paths, also referred to as "block path" or "center path", for example flow path number P6 are thus subject to a correspondingly higher pressure loss with increasing length. Due to the present rather flat design of a flow path - taking into account the plates 21.1, 21. 2 above and below the flow guide 50 - therefore decreases the flow velocity of a coolant, if the flow path width would be kept the same. The concept of the invention provides, in the present embodiment, a concretely realized, clever arrangement of flow paths P1 to P6 which, according to the concept, achieves a velocity distribution in the flow paths P1 to P6 appropriate to the heat input. As already explained, due the comparatively large area of the coolant inlet 24.1, a pressure drop in the inflow from the coolant inlet into the disc bundle, ie kept relatively low in the flow paths provided with numbers P1 to P6. Overall, in the present case, the deflection losses from the "vertical" connection 4.1, 4.2 in the inputs / outputs 24.1 / 24.2 are kept comparatively low. In addition, however, the present embodiment of the insertion part 51.1 of the flow guide element 50 provides a particularly expedient transverse distribution of a coolant 2 which advantageously copes with the heat input.

In order to generate a sufficient pressure drop in areas that have more of a coolant oversupply, to the pressure loss in the relatively shorter second set of paths - as here, for example, provided with number P4 to P6, in particular numbers P5 and P6 flow paths - as high as possible held. This is achieved by the targeted acceleration of the coolant in the from the inlet distance, or cross section P5.1 or P6.1, to the outlet distance, or cross section P5.2, P6.2, strongly narrowing flow paths. Also in the middle part 51.3 of the flow guide 50, this leads to increased pressure losses due to the still higher flow rate. In detail, a pressure curve in the flow paths results as follows - in particular, reference is made to the optimization calculation given below:

In the case of the flow path P1 belonging to the first group of paths, a comparatively high pressure loss in section 1.1 inevitably arises at first - a comparatively high flow velocity of the coolant is also required here in order to avoid boiling of the coolant. Thereafter, according to the concept of the invention, the greatest possible expansion takes place in the region P1.2 - in the present case, the flow path P1 expands to approximately twice the width of the region in P1.1. Specifically, due to the quadratic dependence between pressure loss and velocity, this leads to a halving of the transverse velocity and thus to a pressure drop of only 25% in comparison to a flow path with a constant cross section. Analog is in the range P1.3 reaches four times the width of the flow path P1 compared to the area P1.1, which leads to a reduction of the pressure loss to 1/16 of the pressure loss with a flow path with a constant cross section. This drastic reduction of the pressure loss in the case of the flow path P1 called the "edge or suction path" results in that the pressure loss is kept comparatively low - this makes sense, since edge paths are more likely to suffer from a coolant shortage. In the overall picture, the pressure loss in all paths is set comparatively similar - the latter is a prerequisite for a balanced distribution of coolant also in lateral edge regions "v", "m", "a" of the flow channel.

In the path P2 belonging to the first group of paths, a cross-sectional widening takes place only comparatively late downstream, in the present case toward the end of the inflow region "a", in order to maintain a relatively high flow velocity for the coolant in the region P2.1 of the flow path P2.

In the flow path P3 and P4 takes place at the coolant inlet 24.1 initially strong taper in the areas P3.2 and P4.2 to provide sufficient space for the adjacent paths P1 and P2, which are in the area in P1.2 and P2 .2 already expanding.

In the comparatively short paths P5 and P6 belonging to the second group of flow paths, which in the present case can also be referred to as "center path or longitudinal path", locally high speeds are inevitably to be generated, which, however, are based on a narrow strand in the central part of the heat exchanger, in this case, for example the range "z". The high speed of the coolant in the present case serves to generate a sufficient, driving pressure loss, which can be used by the flow guide 50 or additional beads or baffles, which then also blocking and / or in the transverse direction. Also possible are additionally attached blocking elements to drastically increase the pressure loss in the "z" area.

Overall, the invention has recognized that - as in a heat exchanger to the Fig. 4 is based and in which the first medium, namely the exhaust gas, the same along the main flow longitudinal direction 3, that is axially, flows through - the coolant should generally distribute in the inlet region transverse to the radiator longitudinal direction. However, also for the coolant, the pressure gradient acts mainly in the main flow longitudinal direction 3, so that the coolant preferably the direct flow path - in Fig. 6 the paths P5 and P6 - from entry to exit takes and the transverse distribution is often insufficient. This is all the more critical because, in particular, the inflow region "a" of the exhaust gas is generally completely in the transverse distribution region of the coolant. The invention has recognized, on the one hand, that the better the transverse distribution of the coolant, the less coolant is required in total and the required pump power can be correspondingly reduced. The latter leads directly to a reduced cost and fuel consumption. The transverse distribution is presently achieved in particular by a high flow velocity at the front edge 65 of the flow channel. Because of the required transverse distribution of the coolant, it is unavoidable that even the longest flow paths have the lowest coolant flows, although these should have the highest coolant flows for functional reasons. This problem is solved by the design of the "edge paths" or "suction paths" according to the concept of the invention. In the present embodiment of the Fig. 5 and Fig. 6 On the other hand, a particularly high flow velocity in the "block paths" or center paths "is achieved by arranging flow paths in the inflow region, between which there is usually no connection or a connection which is considerably heavier in the transverse direction than in the longitudinal direction, thereby effectively establishing the driving pressure gradient In addition, a path segment (eg a region P3.1, P4.1 or region P1.1) of a "suction path" may exceptionally be designed as a bottleneck, if particularly high flow velocities are required in this flow path are, in particular transversely flowed parts the paths that lead along the leading edge 65 of the flow channel 20, 20 'along.

• Allgemein berechnet sich ein Druckverlust für einen Strömungspfad zu: $$\mathrm{\Delta p}\mathrm{=}\mathrm{\zeta }\mathrm{*}\left({\mathrm{v}}^{\mathrm{2}}\mathrm{/}\mathrm{\rho }\right)$$
  

ζ ist linear abhängig von der Pfadlänge:
ζ ∼ L_pfad
(alle ∼ Zeichen im Folgenden bedeuten "ist proportional zu")
ζ hängt von der Reynoldszahl "Re" ab. Übliche Werte für Kühlflüssigkeiten (z.B. Wasser-Glysantingemische) sind:

• ζ ∼ Re ^-0,25 (bei laminarer Strömung)
• ζ ∼ const (bei turbulenter Strömung)

A concrete optimization calculation for the design of the flow paths is based on the following principles:

• Generally, a pressure loss for a flow path is calculated to: $$\mathrm{Ap}\mathrm{=}\mathrm{\zeta }\mathrm{*}\left({\mathrm{v}}^{\mathrm{2}}\mathrm{/}\mathrm{\rho }\right)$$
  

ζ is linearly dependent on the path length:
ζ ~ L _path
(all characters below mean "is proportional to")
ζ depends on the Reynolds number "Re". Common values for cooling liquids (eg water-glysantine mixtures) are:

• ζ ~ Re ^-0.25 (at laminar flow)
• ζ ~ const (with turbulent flow)

In "Re", the flow velocity and the hydraulic diameter D _h are linear in each case: $${{}_{"}\mathrm{re}}^{"}\mathrm{~}\mathrm{v}\mathrm{*}{\mathrm{D}}_{\mathrm{H}}\mathrm{,}$$

The dependence of the pressure loss on the velocity thus follows approximately the exponent 1.75 (laminar flow) or 2 (turbulent flow). The dependence of the pressure loss on the hydraulic diameter follows approximately the exponent - 0.25 (laminar flow) or 0 (turbulent flow). If, for the present case of a flow-guiding element, it is assumed that the temperature and pressure of the second medium do not vary too much in the entire flow path, then the viscosity may be constant be accepted. Furthermore, the influence of the speed clearly dominates the influence of the hydraulic diameter. In addition, the flow of the second medium is turbulent in many common heat exchanger applications. Then, with a relatively small error, the pressure loss can be assumed to be proportional to the square of the flow velocity and the hydraulic diameter can be neglected. Furthermore, as a rule, the individual flow paths are rather elongated, and then the pressure losses due to deflection, path widening and narrowing of the path have a relatively small influence and can be neglected for coarse laying of the paths.

v ist umgekehrt proportional zum Pfadquerschnitt, bei konstanter Strömungspfadhöhe also umgekehrt proportional zur Pfadbreite b. Weiterhin ist die Geschwindigkeit v für inkompressible Medien proportional zum Medienmassenstrom öm/öt - für flüssige Medien ist diese Annahme in der Regel zulässig; somit kann für den Strömungspfad n angesetzt werden: $${\mathrm{\Delta p}}_{\mathrm{n}}\mathrm{\sim }\mathrm{\int }{\left(\mathrm{\delta m}\mathrm{/}\mathrm{\delta t}\right)}^{\mathrm{2}}\mathrm{/}{\left(\mathrm{b}\right)}^{\mathrm{2}}\mathrm{\delta l}\mathrm{.}$$

These conditions, given for a given flow control element, allow the pressure loss to be determined via an integral over the path length: $$\mathrm{Ap}\mathrm{~}\mathrm{\int }{\mathrm{v}}^{\mathrm{2}}\mathrm{.DELTA.L}\mathrm{,}$$

v is inversely proportional to the path cross-section, ie at a constant flow path height inversely proportional to the path width b. Furthermore, the velocity v for incompressible media is proportional to the media mass flow öm / öt - for liquid media, this assumption is generally permissible; Thus, for the flow path n can be stated: $${\mathrm{Ap}}_{\mathrm{n}}\mathrm{~}\mathrm{\int }{\left(\mathrm{.DELTA.M}\mathrm{/}\mathrm{.delta.t}\right)}^{\mathrm{2}}\mathrm{/}{\left(\mathrm{b}\right)}^{\mathrm{2}}\mathrm{.DELTA.L}\mathrm{,}$$

The mass flow is constant throughout the path n and it follows: $${\mathrm{Ap}}_{\mathrm{n}}/{\left({\mathrm{.DELTA.M}}_{\mathrm{n}}\mathrm{/}\mathrm{.delta.t}\right)}^{\mathrm{2}}\mathrm{~}\mathrm{\int }{\left(1/\mathrm{b}\right)}^{\mathrm{2}}\mathrm{.DELTA.L}\mathrm{,}$$

Over all flow paths 1 to N the same driving pressure gradient Δp _n = Δp _a acts, so that the respective mass flows in the paths can be calculated to: $$\left({\mathrm{.DELTA.M}}_{\mathrm{n}}\mathrm{/}\mathrm{.delta.t}\right)\mathrm{~}{\mathrm{1}\mathrm{/}\left(\mathrm{\int }{\left(\mathrm{1}\mathrm{/}\mathrm{b}\right)}^{\mathrm{2}}\mathrm{.DELTA.L}\right)}^{\mathrm{1}\mathrm{/}\mathrm{2}}$$

With this formula (1), the mass flow can be calculated for each flow path n and from this at each position I _{h of} the path using the path cross-section A _n (I) the speed or mass flow density (δm _n / δt) / A _n (I ).

bzw. Massenstromverhältnis zwischen einem einzelnen Strömungspfad n und dem Gesamtkanal: $$\left({\mathrm{\delta m}}_{\mathrm{n}}\mathrm{/}\mathrm{\delta t}\right)/\left({\mathrm{\delta m}}_{\mathrm{K}}\mathrm{/}\mathrm{\delta t}\right)\mathrm{\sim }\left[{\left(\mathrm{\int }{\left(\mathrm{1}\mathrm{/}\mathrm{b}\right)}^{\mathrm{2}}\mathrm{\delta l}\right)}^{\mathrm{1}\mathrm{/}\mathrm{2}}\right]/\left[{\left({\left(\mathrm{1}\mathrm{/}{\mathrm{b}}_{\mathrm{K}}\right)}^2{\mathrm{L}}_0\right)}^{1/2}\right]$$

A meaningful reference for the mass flow density is the value that would result for the channel of the second fluid, which is not divided into paths, if it were flowed through completely and homogeneously in parallel (ie without transverse distribution at the inlet / outlet). With the length L _o and the width b _{K of} the channel, the mass flow for the homogeneous flow channel (ie the total flow assuming a homogeneous flow guidance) results: $$\left({\mathrm{.DELTA.M}}_{\mathrm{K}}\mathrm{/}\mathrm{.delta.t}\right)\mathrm{~}{\mathrm{1}\mathrm{/}\left({\left(\mathrm{1}\mathrm{/}{\mathrm{b}}_{\mathrm{K}}\right)}^{\mathrm{2}}{\mathrm{L}}_0\right)}^{\mathrm{1}\mathrm{/}\mathrm{2}}$$

or mass flow ratio between a single flow path n and the total channel: $$\left({\mathrm{.DELTA.M}}_{\mathrm{n}}\mathrm{/}\mathrm{.delta.t}\right)/\left({\mathrm{.DELTA.M}}_{\mathrm{K}}\mathrm{/}\mathrm{.delta.t}\right)\mathrm{~}\left[{\left(\mathrm{\int }{\left(\mathrm{1}\mathrm{/}\mathrm{b}\right)}^{\mathrm{2}}\mathrm{.DELTA.L}\right)}^{\mathrm{1}\mathrm{/}\mathrm{2}}\right]/\left[{\left({\left(\mathrm{1}\mathrm{/}{\mathrm{b}}_{\mathrm{K}}\right)}^2{\mathrm{L}}_0\right)}^{1/2}\right]$$

For a constant height flow path, as in the present embodiment, the channel cross-sectional area is then proportional to the width and results for the specific mass flow or velocity of each width of the path n having the local width b _n (I). and it is possible to calculate the speed in the individual paths related to the velocity of the homogeneously parallel flowed through channel v _K : $${\mathrm{v}}_{\mathrm{n}\mathrm{.}\mathrm{rel}}\mathrm{=}{\mathrm{v}}_{\mathrm{n}}\left(\mathrm{l}\right)\mathrm{/}{\mathrm{v}}_{\mathrm{K}}\mathrm{=}\left({\mathrm{.DELTA.M}}_{\mathrm{n}}\mathrm{/}\mathrm{.delta.t}\right)\mathrm{/}\left({\mathrm{.DELTA.M}}_{\mathrm{K}}\mathrm{/}\mathrm{.delta.t}\right)\mathrm{*}{\mathrm{b}}_{\mathrm{K}}\mathrm{/}{\mathrm{b}}_{\mathrm{n}}\left(\mathrm{l}\right)$$

If the individual flow paths of the channel were sealed against each other (no fluid exchange and no pressure compensation), then the driving pressure drop Δp _{o would be} due to the pressure difference in the inlet and outlet channel of the medium and the length L in determining the homogeneous parallel flow channel is the total length of the channel.

Often, the individual paths - as is the case - not completely sealed against each other and there is a partial pressure equalization between the individual paths of a channel - for example, if only beads in the inlet region support a transverse distribution or a Kühlmittelleitblech in the middle part or in the inlet / outflow as Stegrippe is executed. The reference length L _o does not have to be set as the total length of the flow channel in such cases, but shorter. In such cases, it is useful for the design of the flow _guide to set the length L _o as the longitudinal area L _pfed , in which in the channel of the second medium against each other completed paths (from / to the media in - / - exit) are present. For comparison of the mass flows or the velocities (2) and (3) between the individual paths and the homogeneously parallel flowed total channel, the integral (1) for the individual paths is formed only up to the position L _o and not for the total path of the input. until the exit.

In the special case that this length is shorter than the longest lateral distance of the center of the media inlet / outlet to the more distant channel wall (ie lateral extent of the outer boundary structures) Δy _EA , the reference length L _o = Δy _{EA is} set.

For a flow guide, in particular Kühlmittelleitblech, which should support the transverse distribution of a liquid medium in the inlet / outlet, can be defined particularly meaningful according to the particularly preferred embodiment shown here:

Each flow channel is subdivided in the relevant area (inlet and / or outflow area of the two fluids) into at least three paths on each side, better four or more paths - in the present case there are six paths P1-P6.

The paths are counted in the following way:

Path P1: The outermost path P1 bounded on one side by the channel wall and adjacent to path P2 on its other side. It is initially arranged along the channel front / rear edge approximately transversely to the main flow direction of the heat exchanger (cross flow area) and is then guided parallel to the lateral channel wall after a generally 90 ° deflection (longitudinal flow area). If the coolant inlet / outlet is within the channel and not on the channel side, then there is a path P1 towards each lateral channel wall.

Path P2: Path P2, which is next to path P1 in the channel.

Path P3 .... PN: the following paths - here P3 to P6.

• b_Q: Breite im Querströmungsbereich;durchschnittliche Breite im überwiegend quer zur Hauptströmungsrichtung verlaufenden Teil des Pfades.
• Im Pfad PN (hier P7 oder P6) - d.h. weitgehende Ab-/Zuströmung vom/zum Medienein-/austritt in Hauptströmungsrichtung; kein Segment des Pfades N mit ausgeprägter Querströmung. Für diesen Pfad wird der Öffnungsquerschnitt des Pfades am Medienein-/-austritt als Maß b_Q verwendet, um das Querschnittsverhältnis zwischen "quer" und längs durchströmtem Teil zu ermitteln.
• b_L : Breite im Längsströmungsbereich;
  für L_o = Kanallänge; Breite des Pfades in der Mitte des Wärmetauschers;
  b_L = b(L_o/2)
• andernfalls - Breite des Pfades an der Position L_o: b_L = b(L_o). $$\mathrm{Charakteristisch\; ist\; ein\; Breitenverhältnis}\mathrm{:}\left({\mathrm{b}}_{\mathrm{Q}}\mathrm{/}{\mathrm{b}}_{\mathrm{L}}\right)$$
  

The following widths are defined for the individual paths:

• b _Q : Width in the cross-flow area, average width in the part of the path that is predominantly transverse to the main flow direction.
• In the path PN (here P7 or P6) - ie extensive inflow / outflow from / to the media inlet / outlet in the main flow direction; no segment of the path N with pronounced cross-flow. For this path, the opening cross-section of the path at the media inlet / outlet is used as a measure b _{Q in} order to determine the cross-sectional ratio between "transverse" and longitudinal flow-through part.
• b _L : width in the longitudinal flow area;
  for L _o = channel length; Width of the path in the middle of the heat exchanger;
  b _L = b (L _o / 2)
• otherwise - Width of the path at the position L _o : b _L = b (L _o ). $$\mathrm{Characteristic\; is\; a\; width\; ratio}\mathrm{:}\left({\mathrm{b}}_{\mathrm{Q}}\mathrm{/}{\mathrm{b}}_{\mathrm{L}}\right)$$
  

• Pfade P1-P6 (P7) werden in Hauptströmungsrichtung in einem weiteren Bereich als die seitliche Ausdehnung Δy_EA weitgehend gegeneinander abgetrennt: L_Pfad > Δy_EA.
• Auch im Mittelteil 51.3 des Kühlers (zwischen dem Ein- und/oder Ausströmbereich mit Umlenkungen) ist bevorzugt der Queraustausch nicht vollständig freigegeben, sondern das Medium wird geführt (beispielsweise durch Längssicken oder eine Stegrippe im leichten Durchgang).
• Bei den ersten Pfaden P1, P2, insbesondre Pfad P1, wird die Geometrie gemäß der obigen Definition von v_rel bevorzugt so festgelegt, dass v_rel > 1, besonders v_rel > 1,1, insbesondere v_rel > 1,15 ist.
• Bevorzugt ist v_rel im Pfad P1 und im Pfad P2 größer 1,12.
• Bei den ersten Pfaden P1, P2, insbesondere Pfad P1, ist das Breitenverhältnis zwischen Querströmungsbereich und Längsströmungsbereich b_Q/b_L bevorzugt kleiner als bei den anderen Kanälen: $$\left({\mathrm{b}}_{\mathrm{Q}}/{\mathrm{b}}_{\mathrm{L}}\right)<\mathrm{c}{\left({\mathrm{b}}_{\mathrm{Q}}/{\mathrm{b}}_{\mathrm{L}}\right)}_{\mathrm{n}}$$
  
  
  Für n=N gilt insbesondere bevorzugt c>2, insbesondere c>5 am Besten c > 10. Die gleichen Verhältnisse gelten bevorzugt auch für Pfad P2 im Vergleich zu Pfad PN.
• Zur Erhöhung des treibenden Druckverlustes in den ersten Pfaden P1, P2 können die letzten Pfade PN, PN-1, d.h. vorliegend insbesondere P6, P5 aus der Gruppe der zweiten Pfade gedrosselt werden - beispielsweise durch teilweise Verblockung durch eine Quersicke bzw. durch eine schräg verzahnte Stegrippe oder eine Stegrippe im schweren Durchgang - die Stege stehen schräg oder quer zur Pfadrichtung.
• Im Falle von solchen teilweise verblockten Kanälen ist b_L als lichter Durchtrittsquerschnitt in Pfadrichtung definiert. Im Sonderfall einer Stegrippe im schweren Durchgang (Fluid mäandert durch die Rippe) wird der lichte Durchtrittsquerschnitt zu 0 und das Breitenverhältnis geht gegen unendlich: b_Q/b_L → ∞

This results in geometrically advantageous embodiments, which in embodiments of the Fig. 5 to Fig. 8 are realized.

• Paths P1-P6 (P7) are largely separated from each other in the main flow direction in a range other than the lateral extent Δy _EA : L _path > Δy _EA .
• Also in the middle part 51.3 of the radiator (between the inlet and / or outflow area with deflections) is preferably the cross-exchange is not fully released, but the medium is guided (for example, by longitudinal corrugations or a Stegrippe in easy passage).
• In the first paths P1, P2, in particular path P1, the geometry according to the above definition of v _{rel is} preferably set so that v _rel > 1, especially v _rel > 1.1, in particular v _rel > 1.15.
• Preferably, v _rel in the path P1 and in the path P2 is greater than 1.12.
• In the first paths P1, P2, in particular path P1, the width ratio between the transverse flow region and the longitudinal flow region b _Q / b _{L is} preferably smaller than in the case of the other channels: $$\left({\mathrm{b}}_{\mathrm{Q}}/{\mathrm{b}}_{\mathrm{L}}\right)<\mathrm{c}{\left({\mathrm{b}}_{\mathrm{Q}}/{\mathrm{b}}_{\mathrm{L}}\right)}_{\mathrm{n}}$$
  
  
  For n = N, c> 2, in particular c> 5, is most preferably c> 10. The same conditions are preferably also valid for path P2 in comparison to path PN.
• To increase the driving pressure loss in the first paths P1, P2, the last paths PN, PN-1, ie in the present case in particular P6, P5 can be throttled from the group of the second paths - for example by partial blocking by a transverse bead or by a helical gear Stiff rib or a rib in the heavy passage - the bars are inclined or transverse to the path direction.
• In the case of such partially blocked channels, b _{L is defined} as the light passage cross section in the path direction. In the special case of a Stegrippe in the heavy passage (fluid meanders through the rib), the clear passage cross section to 0 and the width ratio goes to infinity: b _Q / b _L → ∞

Following this concept, the embodiments of the FIGS. 7 and 8 similar to the one in Fig. 6 , In this case, an inflow region 51.1 is subdivided into a plurality of flow paths which are largely dense to one another or difficult to cross in the transverse direction-P1 to P6 or P7 or more. As in Fig. 6 to Fig. 8 As can be seen, these are three flow paths per side or, as a rule, more than five flow paths per side. The concept of the invention can also be applied to a geometrical arrangement of fluid inlet 24.1 and fluid outlet 24.2, which takes place on a central axis 3 of the heat exchanger or also asymmetrically - it can also be provided a complete coolant entry from one side. In a symmetrical distribution, a preferred embodiment provides that at least five flow paths are provided - two on each side and at least one further in the longitudinal direction. For asymmetric or single-sided inflow, at least three paths are provided - at least two on each side and another in the longitudinal direction.

Overall, the embodiments of the Fig. 6 to Fig. 8 together that a cross-sectional ratio, for example, the areas P1.1 to P1.2 and / or the areas P1.1 to P1.3 and optionally other channels in the transverse area P2.1 to P2.2 and / or P2.2 to P2. 3 is significantly smaller than the aspect ratio of the direct longitudinal so-called "center or block flow paths" - here, for example, the ratio in the ranges P5.1 to P5.2 or P6.1 to P6.2 - is. The cross-sectional ratio between inlet and outlet from the inflow region from flow path P1 to the maximum preferably continues to increase.

It is not excluded that certain flow paths are not formed in accordance with this order for reasons of production or for the representation of geometrically related geometrical arrangements.

In particular, the inlet to outlet cross-section ratio of the flow paths in the longitudinal direction, for example, the ratio of the areas P6.1 to P6.2 at least three times as large, preferably at least six times as large, in particular more than ten times as large as the cross-sectional ratio in the ranges 1.1 to 1.3.

In summary, the invention proceeds from a flow guide element 50 for arrangement in a heat exchanger 10, 10 'to a heat flow influencing flow guidance of a fluid along a main flow longitudinal direction 3 from a fluid inlet 24.1 to a fluid outlet 24.2. According to the concept of the invention, the flow guide element 50 has a flat base plane 52 extending in the main flow longitudinal direction 3, wherein at least partially lateral boundary structures 57 rise above the base plane 52 to form at least one flow path 59, P1-P7. For influencing the flow guide in the main flow longitudinal direction 3, the at least one flow path 59, P1 - P7 an upstream first distance A _is of the lateral boundary structures 57, and a downstream second distance A _from the lateral boundary structures 57, wherein the distances are different such that the Flow path associated pressure loss of the fluid from a location associated with the upstream first distance to a position associated with the downstream second distance is different than a pressure loss of an imaginary flow path with substantially equally spaced boundary structures. Advantageously, such a flow path is suitable for guiding the fluid comparatively more strongly into regions of particularly high heat exchange and / or with a coolant undersupply or for supplying the fluid to comparatively weaker regions with comparatively little heat exchange and / or with a coolant oversupply.

LIST OF REFERENCE NUMBERS

1

first fluid, exhaust

2

second fluid, coolant

2.1, 2.2

second fluid, low temperature coolant

3

Main flow longitudinal direction, central axis

4.1

insertion support

4.2

discharge pipe

5.1, 6.1

Fluid inlet opening

5.2, 6.2

Fluid outlet opening

7.1

admission diffuser

7.2

outlet diffuser

10, 10 '

heat exchangers

10.1

High temperature stage

10.2

Low temperature stage

11

casing

12

housing cover

13

block

20

flow channel

21.1, 21.2, 21.3

plates

23, 25

gap

24.1

fluid entry

24.2

fluid outlet

40

heat distribution

41

heat input

50

flow guide

51.1

inflow

51.2

exit part

51.3

middle part

52

ground plane

53

web ribs

55

Through openings

56.1, 26.2

line

57

limiting structures

59

Flow path, flow channel

61

top

63

bottom

65

leading edge

P1.1 - P6.1

upstream cross sections

P1.2 - 4.2, P1.3-3.3

downstream cross sections

P1 - P6

flow path

a

inflow

s

page range

v

leading edge

z

central area

m

extension

a

expansion

Claims (15)

Flow guide (50), in particular in the form of a deep-drawing punching or pressing part, for arranging in a heat exchanger (10, 10 ') for a heat exchange influencing flow guidance of a fluid along a main flow longitudinal direction (3) of a fluid inlet (24.1) to a fluid outlet (24.2)
marked by
a planar ground plane (52) extending in the main flow longitudinal direction (3), wherein at least partially lateral boundary structures (57) rise above the ground plane (52) to form and at least partially border a number of flow paths (59, P1-P7), and for influencing the flow guide in the main flow longitudinal direction (3) at least one flow path (59, P1 - P7) an upstream first distance (a _a) between two associated with the flow path lateral boundary structures (57) and a downstream second distance (a) _for the lateral boundary structures (57), wherein the distances are different. Flow guiding element according to claim 1,
characterized in that
the distances are so different that a pressure loss of the fluid associated with the flow path (59) from a first location associated with the upstream first distance to a second location associated with the downstream second distance is different than a pressure loss of an imaginary flowpath having substantially equidistant confining structures. Flow guide (50) according to claim 1 or 2,
characterized in that
the flow path (59) has a, preferably continuously, changing distance of the lateral boundary structures (57). Flow guiding element according to one of claims 1 to 3,
characterized in that
the number of at least three, preferably at least four, preferably more than four, flow paths (59, P1-P7) is provided. Flow guiding element according to one of claims 1 to 4,
characterized in that
the number of flow paths (59, P1-P7) are juxtaposed on a lateral extent (Δy _EA ) between two outer, lateral boundary structures of the flow guide. Flow guiding element according to one of claims 1 to 5,
characterized in that
at least one first (P1, P2) and at least one second (P2-P7) flow path is provided, wherein a first flow path is arranged laterally outside outside a second flow path, or a second flow path is arranged laterally inside next to a first flow path. Flow guiding element according to one of claims 1 to 6,
characterized in that
at least one first (P1, P2) and at least one second (P2-P7) flow path is provided, wherein a first flow path of an outer, lateral boundary structure is arranged closer than a second (P2-P7) flow path or a second flow path (P2- P7) is arranged closer to a fluid inlet (24.1) or a fluid outlet (24.2) than a first (P1, P2) flow path. Flow guiding element (50) according to one of claims 1 to 7,
characterized in that
at least one first (P1, P2) and a second (P3-P7) flow path (59) is provided, from an upstream first location to a downstream second location along the main flow longitudinal direction (3) of the first flow path (P1, P2, P3, P4) is longer than the second flow path (P5, P6). Flow guiding element (50) according to one of claims 1 to 8,
characterized in that
a first flow path (P1-P4) has an upstream first distance (P1.2, P2.2, P3.2) of the lateral restriction structures (57) and a downstream second distance (P1.3, P2.3, P3.3) of the lateral boundary structures (57), wherein the first distance is less than the second distance, in particular a distance ratio of the first distance to the second distance is less than in a second flow path. Flow guiding element (50) according to one of claims 1 to 9,
characterized in that
a second flow path (P5, P6) has an upstream first distance (P5.1, P6.1) of the lateral boundary structures (57) and a downstream second distance (P5.2, P6.2) of the lateral boundary structures (57) the first distance is greater than the second distance, in particular a distance ratio of the first distance to the second distance is greater than in a first flow path. Flow guiding element (50) according to one of claims 1 to 10,
characterized in that
a second flow path (P5, P6) extends substantially in the main flow longitudinal direction (3), in particular comparatively directly, in particular longitudinally extended or diametrically to the flat ground plane (52), from a fluid inlet (24.1) to a fluid outlet (5.2, 6.2, 24.2) oriented towards is, in particular virtually no cross-section extending transversely to the main flow longitudinal direction (3), or practically has only approximately one longitudinal region extending in the main flow longitudinal direction (3). Flow guiding element (50) according to one of claims 1 to 11,
characterized in that
a distance ratio of a first downstream distance to a second downstream distance from path to path between a first flow path (P1) and a second flow path (P6) increases, in particular at a second flow path (P6) in the range of two to ten times a first flow path ( P1), preferably at 3-fold, 6-fold or 10-fold. Flow guiding element (50) according to one of claims 1 to 12,
characterized in that
a first flow path (P1, P2, P3, P4), in particular except a virtually only in the main flow longitudinal direction (3) extending longitudinal region, at least partially transverse to the main flow longitudinal direction (3) extending transverse region, in particular in the region of a fluid inlet (24.1) and / or Fluid outlet (5.2, 6.2, 24.2), in particular comparatively indirectly, in particular close to the periphery and / or near the front edge (65) of the planar ground plane (52), from a fluid inlet (5.1, 6.1, 24, 24.1) to a fluid outlet (5.2, 6.2 , 24.2). Flow guiding element (50) according to one of claims 1 to 13,
characterized in that
a first flow path (P1, P2, P3, P4) is adapted to lead an increased fluid flow rate compared to a first flow path in an otherwise identical, imaginary flow path arrangement having a first and second flow paths having substantially equidistant boundary structures. Heat exchanger (10, 10 ') for heat exchange between a first fluid and a second fluid comprising: - A in a housing (11) arranged block (13) for the separate and heat exchanging guidance of the first fluid and the second fluid along a main flow longitudinal direction (3) from a fluid inlet (24.1) to a fluid outlet (24.2), wherein to a heat exchange influencing flow guidance of one of the fluids, in particular of the second fluid, a flow guide element (50) is provided according to one of claims 1 to 14.

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