MXPA06004784A - Flow channel for a heat exchanger, and heat exchanger comprising such flow channels - Google Patents

Abstract

The invention relates to a flow channel of a heat exchanger with two parallel heat transfer areas (F1, F2) that are arranged at a distance corresponding to a channel height H. Each heat transfer area (F1, F2) is provided with a structure that is formed by a plurality of structural elements which are placed next to each other in rows running perpendicular to the direction of flow P and extend into the flow channel. Each structural element has a width B, a length L, a height h, a flow-off angle a, and an overlap U while being provided with a longitudinal axis.

Description

CHANNEL OF FLOW FOR A HEAT EXCHANGER, AND HEAT EXCHANGER HAVING FLOW CHANNELS THIS TYPE The invention relates to a flow channel, through which a medium can flow in a flow direction, of a heat exchanger according to the preamble of patent claim 1. The invention also relates to a heat exchanger. heat having flow channels according to the preamble of patent claim 40. A first means, for example, an exhaust gas or a liquid refrigerant, flows through the flow channels for heat exchangers, and these channels flow delimit its first medium from a second medium, to which the heat of the first medium is to be transferred. Flow channels of this type can be tubes with a round cross section, rectangular tubes, flat tubes, or even pairs of disks, in which case two plates or disks are connected on the edge sides. The means that exchange heat with each other are generally different; As an example, a hot exhaust gas loaded with particles flows into the tubes, and a liquid refrigerant flows around the exhaust gas pipes on the outside side, leading to different heat transfer conditions on the inner sides and outside of the tubes. It has therefore been proposed, in particular for exhaust gas pipes, that the turbulence generators installed in a V-shape and in a diffuse manner be installed on their inner side, these turbulence generators being responsible for swirling the flow and improving the heat transfer on the exhaust gas side while at the same time preventing the deposition of particles. Solutions of this type for exhaust gas heat exchangers are known from the following documents in the name of the Applicant: EP-A 677 715, DE-A 1 95 40 683, DE-A 196 54 367 and DE-A 1 96 54 368. These known exhaust gas heat exchangers have rectangular tubes made of stainless steel that are assembled from two welded half shells together, in which the turbulence generators, known as fins, are formed or stamped, installed one behind the other. other. The pairs of fins of the two half-shells move relative to each other either in the longitudinal direction of the tubes, ie in the direction of flow (DE 196 54 367, DE 1 96 54 368) or are installed opposite one to another (DE 195 40 683). DE-A 101 27 084 on behalf of the Applicant has proposed a heat exchanger, in particular an air cooler / cooler with flat tubes and corrugated blades, in which the flat sides of the flat tubes have a structure comprising structural elements. The structure elements are elongated in shape, are installed in a V-shape in rows transversely with respect to the flow direction of the coolant and / or transversely to the longitudinal axis of the tubes and function as swirl generators to increase the transfer of heat on the refrigerant side. The swirl generators are stamped on the two walls of the opposite tube and project inward in the refrigerant flow. The rows of swirl generators on one side of the flat tube move in the direction of flow with respect to the rows on the other side of the flat tube. It is therefore also possible for the inward projection that the height of the swirl generators be greater than half the clear width of the cross section of the flat tube. EP-A 1 061 319 has described a flat tube for a motor vehicle radiator having on its flat sides a structure comprising individual elongated structure elements installed in rows. The rows with differently oriented structure elements are installed in the flow direction, so that the flow inside the flat tube deviates approximately in a zigzag fashion. In particular, however, the rows comprising structure elements in a flat tube are installed offset in the direction of flow with respect to the rows on the opposite flat tube side. Therefore, a smooth region of the inner wall of the flat tube in each case lies opposite a row of structure elements. The flow within the refrigerant tube is therefore alternative but not simultaneously influenced by the structure elements on one side of the flat tube and on the other side of the flat tube. This is proposed, among other things, to prevent the tubes from blocking. There is also potential in this respect with respect to heat transfer capacity. It is an object of the present invention to improve a flow channel and a heat exchanger of the type described in the introduction with respect to its heat transfer capacity, in particular to increase the formation of turbulence and swirl, while the loss of pressure it should only rise to an acceptable degree. This object is achieved by the features of patent claim 1. According to the invention, it is stipulated that the structural elements installed in particular in rows on one side and the other side of the flow channel are placed substantially opposite each other, that is to say, they are in each case installed at approximately the same level as seen in the direction of flow. The structure elements or rows lying opposite one another may also be displaced with respect to one another in the direction of flow, but only to such a degree that a cover still exists. Therefore, the structure elements projecting in the flow channel from one surface of the heat exchanger and the other surface of the heat exchanger are simultaneously involved in the flow and swirling the flow, which leads to an improvement in the heat transfer in the inner side of the flow channel. Furthermore, for example, in the case of an exhaust gas flow, under certain circumstances, the deposition of particles is prevented. The loss of pressure is maintained within acceptable limits. The flow within the flow channel is therefore disturbed from both sides simultaneously, i.e., both boundary layers separate simultaneously, which leads to particularly extensive swirling. The structure elements or rows of structure elements lying opposite each other can likewise be located on the outer side of the flow channel, in the case of an exhaust gas cooler on the cooling side. Advantageous configurations of the invention will come out of the sub-claims. In the context of the present invention, a row comprising structure elements is formed by one or more structure elements, which are installed substantially next to each other in the flow direction P. In particular, therefore, a row can also be formed by a single structure element without, for example, additional structural elements installed next to it. The advantageous configurations of the invention provide different modalities of the structure elements, which can be rectilinear or curved in shape, that is, they can have a constant or variable inactive flow angle with respect to the flow direction. The inactive flow angle change from a relatively long active flow angle to the inactive flow angle results in a "gentle" flow deviation and therefore a loss of pressure in some way reduced. According to an advantageous configuration of the invention, the structure elements with a row can be installed offset, that is to say, the structure elements, although installed in a row passing transversely with respect to the direction of flow, are installed staggered in the direction of flow. This likewise has the advantage of a lower pressure loss. In addition, the opposite rows, that is to say, on one side of the flat tube or the other, they may be installed offset relative to each other in the flow direction, in which case, however, a cover is always retained between the two rows. This displacement in the direction of flow also results in a lower pressure loss. If the structures lying opposite each other are touched and if they are joined to each other by welding or fusion, it is possible to increase the resistance. According to another variant, the structure elements are not installed at equal distances within a row, but preferably these rows have gaps, which in each case have elements of structure lying opposite each other on the opposite side, "filling" thus empty, as seen in the plan view. This, likewise, has the advantage of a lower pressure loss. It is also possible for inlays and / or networks to be stamped in or out (as seen in the flow direction P) between or near the structure elements and / or between or within the "structure rows" ( rows comprising structure elements), to achieve a "support" action and therefore an increase in resistance. Swirling structures can likewise be fully or partially responsible for this function. According to an advantageous embodiment, the surfaces of the heat exchanger lying substantially opposite each other, and in particular the structural elements installed therein, are curved. The advantages according to the invention are achieved in particular with tubes having an oval or circular cross section. According to an advantageous embodiment, the surfaces of the heat exchanger that lie substantially opposite each other are primary heat engineering surfaces. According to a variant, the surfaces of the heat exchanger, in contrast, are secondary heat engineering surfaces, which are formed in particular by wings, nets or the like which are preferably clamped, welded or fused to the flow channel. According to an advantageous embodiment, the height h of the structure elements is in the range of 2 mm to 10 mm, in particular in the range of 3 mm to 4 mm, and is preferably approximately 3.7 mm. According to an advantageous embodiment, the flow channel is rectangular and has a width b which is in particular in the range of 5 mm to 120 mm, preferably in the range of 10 mm to 50 mm. According to an advantageous embodiment, a hydraulic diameter of the flow channel is in the range of 3 mm to 26 mm, in particular in the range of 3 mm to 10 mm. According to an advantageous embodiment, at least one, in particular each row of structure elements, comprises in each case a plurality of structure elements. The object of the invention is also achieved by the features of patent claim 40. According to the invention, the above mentioned flow channels are provided as flat, round, oval or rectangular tubes of a heat exchanger, advantageously an exchanger of exhaust gas heat. The installation of the structure elements according to the invention, that is, the way they are advantageously stamped on the inner walls of the tube, improves the performance of the heat exchanger. The structural elements installed in rows are particularly advantageous for exhaust gas heat exchangers, since in this case the deposition of particles inside the flat tubes is also avoided. A refrigerant that is taken from the refrigerant circuit of the internal combustion engine by discharging the exhaust gases flows around the outside of the exhaust gas pipes. It is also possible for the structures to be stamped on plates or discs so that the heat exchangers are produced from them. Exemplary embodiments of the invention are illustrated in the drawings and are described in more detail in the text that follows. In the drawings: Fig. 1 shows a flow channel according to the prior art, Figs. 2a, b, c show a cross section through flow channels, Fig. 3 shows a flat tube with a structure according to the invention, Fig. 4 shows a half cover of the flat tube of the Fig. 3, Figs. 5a, b, c, d show various structure elements, Figs. 6a, b, c, d, e, f, g, h show structures according to the invention in flow channels, Figs. 7a, b show additional structures according to the invention, Fig. 8 shows an additional structure according to the invention, Figs. 9a, b, c, d show structural elements of counterimage, counterimage element of structures, Figs. 10a, b, c, d show displaced-parallel structure elements, Figs. 1 1 a, b, c, d show rows of structure elements with modifications, and Figs. 12a, b, show additional elements of structure. Fig. 1 shows a simplified illustration of a flow channel 1 which is formed as a rectangular tube and has a rectangular inlet cross section 2, two opposite flat sides F1, F2 and two opposite narrow sides S1, S2. A flow medium, for example, an exhaust gas, flows through the passage 1 in the direction indicated by the arrow P. The swirl generators 3a, 3b, 4a, 4b oriented in V-shapes are installed on the lower plane side F2 and, when generating swirl, the effect of increased turbulence of the flow and at the same time, in the case of an exhaust gas flow, prevent the deposition of particles. This illustration corresponds to the prior art mentioned in the introduction. According to the above the swirl generators 3a, 3b and 4a, 4b, which are in each case installed in pairs, established in a V-shape and widened in a diffuse manner in the direction of flow, are also referred to as what is known as fins.

Fig. 2a shows the cross section through a flow channel 1 which is formed as a flat tube and in which the pairs of fins 5a, 5b and 6a, 6b are installed both on the upper plane side F1 and the flat side lower F2. The pitch cross section has a pitch height H and a pitch width b. The fins 5a, 5b, 6a, 6b have a height h projecting in the passage cross section. This installation of fins in the same way corresponds to the prior art cited in the introduction. The designations F1, F2 also apply to the exemplary embodiments according to the invention described below. Fig. 2b shows the cross section through a flow channel V which is formed as a round tube and in which the structure elements 13 'and 13 are installed both on the upper plane side F1 and on the lower plane side F2 , respectively. The passage cross section has a step height H. Fig. 2c shows a cross section through a flow channel 1 which is formed as a flat tube and in which the heat exchange surfaces F1, F2 represent secondary surfaces of heat engineering, since they do not directly transfer heat from one medium to the other. The surfaces of the heat exchanger have structural elements 13, 13 '. Fig. 3 shows a flow channel according to the invention, which is formed as a flat tube 7, part of the Gual is illustrated in plan view. The flat tube 7 has a longitudinal axis 7a, a width b and two rows 8, 9 of structure elements or fins 10, 1 1 which are installed in a V-shape and are in each case stamped both on the upper side F1 and on the bottom side F2 of the flat tube 7, specifically in the same pattern, so that in each case the row of upper fins covers the row below it. In each case eight fins, evenly distributed over the full width b, are installed in a row; however, it is also possible that there are six or seven fins for the same width. In the case of narrow tubes, discs or plates, the number of fins may also be less than six, and in the case of wider tubes or discs / plates, there may also be more than eight fins. The two rows 8, 9 are at a distance s, which is measured from center to center and amounts to approximately two to six times the length of the fins, each other. Between the individual rows, therefore there is in each case a smooth region in which, for example, support structures have been stamped. The rows of fins extend over the entire length of the flat tube 7, in each case at the distance s, specifically on both sides of the flat tube 7. Fig. 4 shows a lower half cover 7b of the flat tube 7 as seen in FIG. direction of the longitudinal axis 7a of the flat tube 7. The covering half 7b has a base F2 and two side members 7c, 7d, fins 1 1 'installed on the base or bottom side F2, ie, stamped on the tube wall. The upper half cover is not illustrated; it is formed in a counterimage manner and is longitudinally attached to the lower half cover 7b on the side members 7c, 7d. The fins 1 1 * have a height h by which they project into the clear transverse region of the flat tube 7. The tube can also be produced from a sheet of metal that deforms and is welded on one side. In a preferred exemplary embodiment, the width b of the flat tube is 40 mm or 20 mm, the total height of the flat tube is approximately 4.5 mm and the height h of the fins is approximately 1.3 mm. As a result of the fins projecting in the cross section of pitch from both sides, in each case at a height of 1.3 mm, giving a clear step height of 4.0 mm, a clear cross section height of 1.4 mm it remains for a core flow. The distance s between the rows is approx. 20 mm The flat tube 7 is preferably used for exhaust gas heat exchangers (not shown) that are known per se, that is, an exhaust gas from an internal combustion engine of a motor vehicle flows through it. its internal side, while the refrigerant of a refrigerant circuit of the internal combustion engine cools it on its outer side. The outer side of the flat tube 7 - as known from the prior art - can be smooth and can be maintained at a distance from the adjacent tubes for example, by stamped inlays. However, it is also possible that blades are provided on the outer side of the flat tube 7 to improve the heat transfer on the cooling side. Figures 5a, 5b, 5c and 5d show individual structure elements that are provided for a structure according to the invention in the flow channel. Fig. 5a shows an elongated structure element 13 having a longitudinal axis 13a forming an angle a, the inactive flow angle, with a reference line q. The direction of flow is the same for all the illustrations in Figures 5a to 5d and is indicated by an arrow P. The reference line q passes perpendicular to the flow direction P. The structure element 13 has a length L and a width B. The latter can be constant or variable, that is, it can increase in direction P. Fig. 5b shows an elongated but inclined structure element 14 with two longitudinal axes 14a, 14b that are at an inclination with respect to each other and respectively, they include an angle a and ß with the reference line q. ß is referred to herein as the active flow angle and a as the inactive flow angle. The flow indicated by the arrow P is therefore deviated in two stages, that is, initially only lightly and then to a greater degree. This results in a lower pressure loss compared to a structure element as shown in Fig. 5a with the same inactive flow angle a. The length of the structure element 14 along the longitudinal axes 14a, 14b is denoted by L. Fig. 5c shows an arched structure element 15 having a curved longitudinal axis 15a corresponding to an arc of radius R. The water angle above is referred to as the active flow angle ß and the downstream angle as the inactive flow angle a. In this case too, the flow is initially shifted gently through the angle (90 ° -ß) and then to a greater degree by the angle (90 ° -a). This continuously increasing deviation of the flow of the same mod results in a lower pressure loss as compared to the structure element 13 as shown in Fig. 5a. The length of the structure element 15 along the longitudinal axis 15a is denoted by L. Fig. 5d shows a further embodiment of a structure member 16, which is approximately Z-shaped and also has a longitudinal axis 16a passing through a Z-shape. The longitudinal axis 16a connects two sections of arc of different curvature, but with the same radius R1 = R2. The active flow angle is denoted in the present by ß, the inactive flow angle per a, -corresponding to a flow deviation of (90 ° -a), which takes place in the central region of the structure element 16. The flow over and outside this structure element takes place practically in the direction of flow P. This results in flow deviating with particularly low pressure losses. The length of the structure element along the longitudinal axis 16a is denoted by L. Figs. 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h show installation patterns of the structure elements 13 according to Fig. 5a, specifically in rows in part of a flow channel. In exemplary embodiments that are not illustrated, only single structure elements lie opposite each other. Fig. 6a shows the elongated structure elements 13 in each case installed in two rows 17, 18 which are at a distance s in the flow direction P. The structure elements 13 illustrated by solid lines are stamped on the upper side F1 of the flow channel. Elements of structure 13 'illustrated by dashed lines and likewise installed in rows 19, 20 have been formed on the side or surface of the lower heat exchanger F2 of the flow channel. The rows are illustrated by striped lines of demarcation. The structure elements 13 'on the lower surface F2 are oriented in the opposite direction to the structure elements 13 on the upper surface F1, ie they have an inactive flow angle opposite to (cf Fig. 5a). In addition, rows 19, 20 move in the flow direction P with respect to rows 1 7, 18, specifically for the quantity f. The structure elements 13 and 13 'and the associated rows 17, 18, 19, 20 each have a depth T, ie. An extension in the flow direction P. The displacement f is smaller at the depth T, so that a cover Ü resulting from the difference between T and f remains between rows 18, 20 and 17, 19. A cover Ü of 100% , in the case of rows with the same depth T, it means that the displacement equals 0 (f = 0). In the case of rows with different depths T1 and T2, that is, for example T1 <; T2, a cover of 100% means that the cover Ü is equal to the smallest depth T1 (Ü = T1). A displacement between rows 17, 19 and 18, 20 lying opposite one another advantageously results in a lower pressure loss than in the case of rows without a displacement. Fig. 6b shows a different pattern of structure elements 13 installed in rows, specifically in a row 21 and a row 22 with different inactive flow angles a (not shown). The structure elements 13 shown by solid lines have been stamped on the upper side F1 of the flow channel. Structure elements 13 'illustrated by dashed lines at the same level, in the flow direction P, with an opposite orientation are installed on the lower surface F2 of the flow channel, with the result that an upper structure element 13 and an element of lower opposite structure 13 ', when viewed in plan view, in each case appear in the form of a cross. The upper row having elements of structure 13 therefore does not move with respect to the lower row comprising structure elements 13 '; the cover Ü is 100%. Fig. 6c to Fig. 6h show additional installation patterns for the structure elements 13, 13 'on the upper side F1 (illustrated by solid lines) and the lower side F2 (illustrated by dashed lines) of the flow channel. In addition, Fig. 6h shows support elements 13"on the outer side of the flow channel, such support elements in this exemplary embodiment are installed adjacent to the structure elements 13, 13 'and in particular within the rows formed by the structure elements 13, 13 'It is preferable that the support elements are stamped into the wall of the flow channel For desired support of the respective flow channel, the support elements 13"advantageously have a height corresponding to the desired distance between two flow channels or between the respective flow channel and a housing wall of a heat exchanger. Figures 7a and 7b show additional variants for the installation of the structure elements 13 in rows.

Fig. 7a shows part of a flow channel with two rows 23, 24 of structure elements 13 installed in a form V on the upper side F1. The structure elements 13 are not installed at constant distances close to one another, but preferably have gaps 25, 26, 27 which, however, are filled on the lower side F2 by structure elements 13 ', so that when observed from above the impression is of a continuous uniform installation of structure elements 13 and 13 '. This installation of rows 23, 24 with "empty" and corresponding rows on the lower side results in a lower pressure loss for the flow in direction P, because the structural elements - as seen in the width direction - only intervene in the flow alternately from above and below. Fig. 7b shows a similar installation of structure elements 13 oriented parallel to one another with gaps between them on the upper side F1 in rows 28, 29. The gaps between the structure elements 13 are again filled by structure elements 13 '. on the lower side F2, the structure elements 13 on the upper side F1 and the structural elements 13 'on the lower side F2 complementing each other to form a zigzag installation when viewed from above. This installation in the same way includes relatively low pressure losses. Fig. 8 shows another embodiment for the installation of structure elements 13 and 13 'in two rows 30, 31 on the upper side F1. The structure elements 13 of row 30 and the structure elements 13 'of the opposite row (on the lower side F2) are installed parallel to and at the same distance from one another. The same applies analogously to the second row 31, except that the inactive flow angle is directed in an opposite manner, resulting in a flow deviation as seen in the flow direction P. Figures 6a, 6b, 7a, 7b and 8 in each case illustrated structures having the elements of structure 13 as shown in Fig. 5a. The structure elements 13 can also be replaced by elements of structure 14 (in Fig. 5b), 15 (Fig. 5c) or 16 (Fig. 5d). It would also be possible to use different structure elements, for example 13 and 14, within a single row. Figs. 9a, 9b, 9c, 9d show variants of the structure elements 13, 14, 15, 16 that are in a counterimage installation: the result is therefore what is known as pairs of fins 32, 33; 34, 35, with a minimum distance a in each case being provided between two structure elements. The direction of flow generally takes place in the direction indicated by the arrow P, with the flow over the pairs of fins commonly taking place at the narrowest point a. This results in the different pairs of fins 32 to 35 having decreased pressure losses in that order. These pairs of fins can be installed in rows close to each other, for example as illustrated in Figures 6 to 8. Figures 10a, 10b, 10c, 10d show further variations of the approximate structure elements 13, 14, 15, 16 for a parallel change. This results in double elements 36, 37, 38, 39 in each case having the same distances a on the sides of active flow and inactive flow, which, for example, can be integrated into the structures shown in Figs. 6 to 8. It is in this important context that the structure elements of a row in the upper part and / or the lower part do not necessarily have to have the same geometrical shape or dimensions, as shown by way of example in the base of four structure elements in Fig. 1 1 a. Preferably, as shown in Fig. 1 1 b, it is possible for the structure elements to be installed in a displacement f in the direction of flow P. In Fig. 1 1 c, the angles of inactive flow of the elements of structure 13 vary, and in Fig. 1 1 d the lengths L1, L2 of the structure elements 13 vary. A combination (not illustrated) of the variants illustrated in Figs. 1 1 b, 1 1 c, 1 1 d is in the same way possible. It is also possible that these variations occur in the upper and / or lower surface F1 or F2, respectively. Fig. 12a shows an additional structure element 43, which is formed as an angle with two straight members 43a, 43b which are connected by an arc 43c at its apex. In this aspect, this structure element 43 represents a modification of the pair of fins 32 illustrated in Fig. 9a. The medium preferably flows in the apex direction 43c, as indicated by the arrow P. Fig. 12b shows a further modification of the pair of structure elements 34 as shown in Fig. 9c, mainly a structure element 44 with two curved members 44a, 44b that are connected by an arch 44c at the apex. The structure element 44, on which the medium in the same way flows in the direction of the apex 44c as indicated by the arrow P, initially affects a small flow deviation, when it becomes larger on the members 44a, 44b curving in the flow. The elements shown in Fig. 12a and Fig. 12b can be used in all the installations shown above where two structures installed in a V-shape are used. In principle, it is possible that all the described structures are combined with each other in any desired way.

Claims (48)

1. CLAIMS 1. A flow channel (1), through which a medium can flow in a flow direction P, of a heat exchanger having two heat exchanger surfaces (F1, F2), which lie substantially opposite each other, are in particularly installed parallel and / or to a space of pitch height H, and each have a structure formed of a multiplicity of structure elements which are installed next to each other in rows transversely with respect to the flow direction P and project into the flow channel, the structure elements each having a width B, a length L, a height h; an inactive flow angle a and a longitudinal axis, characterized in that at least two rows (17, 18, 1, 20) comprising structural elements (13, 13 ') on substantially opposite heat exchanger surfaces (F1, F2) have one cover (Ü) with others.
2. 2. The flow channel according to claim 1, characterized in that the cover (Ü) is 100%.
3. The flow channel according to claim 1, characterized in that at least one structure element (13) is elongated, in particular rectangular in shape and has a straight longitudinal axis (13a).
4. The flow channel according to claim 1, characterized in that at least one structure element (14) is elongated and angled in shape and has an angled longitudinal axis (14a, 14b) that forms the inactive flow angle to and an angle of active flow ß with the flow direction P.
5. 5. The flow channel according to claim 1, characterized in that at least one structure element (15) is arcuate in shape and has a longitudinal axis (15a) that is curved with a radius R and forms the inactive flow angle (a) and an active flow angle ß with the flow direction P.
6. 6. The flow channel according to claim 1, characterized in that at least one structure element (16) is approximately Z-shape and has a double-curved longitudinal axis (16a) with spokes (R1, R2) that forms the inactive flow angle a and an active flow angle ß with the flow direction P.
7. 7. The flow channel according to claim 1 , characterized in that at least one Structure element (43) is V-shaped and has straight V members V (43a, 43b).
8. The flow channel according to claim 1, characterized in that at least one V-shaped structure element (44) has V-members (44a, 44b) that are bent away from the flow direction.
9. The flow channel according to one of claims 1 to 8, characterized in that the height h of at least one of the structure elements (13, 14, 15, 16) is 20% to 50% of the pitch height H 10.
10. The flow channel according to claim 9, characterized in that the length L of the at least one structure element (13, 14, 15, 16) is two to twelve times the height h of the structure element. eleven .
11. The flow channel according to one of claims 1 to 10, characterized in that the distance s between the rows amounts to 0.5 to eight times the depth T.
12. 12. The flow channel according to one of claims 1 to 11, characterized in that the distance s in each case two rows varies in the flow direction P.
13. 13. The flow channel according to one of claims 1 to 10, characterized in that at least one structure element (13, 14, 15, 16) has a constant width B in the range of 0.1 to 6.0 mm, preferably in the range of 0.1 to 3.0 mm.
14. The flow channel according to one of claims 1 to 10, characterized in that at least one structure element (13, 14, 15, 16) has a width that increases in the direction of flow between a starting width B1 and a finished width B2, the starting width B1 being in the range of 0.1 to 4 mm and the finished width B2 being in the range of 0.1 to 6 mm.
15. The flow channel according to one of the preceding claims, characterized in that the inactive flow angle a is in the range of 20 to 70 °, preferably in the range of 40 to 65 °, and in particular it has a value of 50 to 60 °.
16. 16. The flow channel according to one of claims 4 to 6 and 15, characterized in that the active flow angle ß is in each case longer than the inactive flow angle a.
17. 17. The flow channel according to claim 6, characterized in that the radius R is in the range of 1 to 10 mm, preferably in the range of 1 to 5 mm.
18. 18. The flow channel according to claims 5 and 17, characterized in that the radii R1 and R2 are equal to the radius R.
19. 19. The flow channel according to one of claims 1 to 18, characterized in that one row (17, 18, 19, 20) in each case has identical structure elements (13, 13 ').
20. 20. The flow channel according to one of claims 1 to 18, characterized in that one row in each case has different structure elements.
21. 21. The flow channel according to claim 19, characterized in that individual structure elements (13, 14, 15, 16) are installed next to each other in pairs (32, 33, 34, 35) at a distance a and of counterimage with respect to each other.
22. 22. The flow channel according to claim 19, characterized in that some or all of the structure elements (13, 14, 15, 16) are parallel but move with respect to each other and are installed in pairs (36, 37, 38, 39) at a distance transversely to the direction of flow.
23. 23. The flow channel according to claim 21 or 22, characterized in that a distance a between two structure elements can vary within at least one row.
24. 24. The flow channel according to claim 21 or 22, characterized in that the distance a is in the range of 0 to 8 mm.
25. 25. The flow channel according to claim 19, 21, 22 or 24, characterized in that the individual structure elements (13) of a row (40) are displaced by an amount f relative to each other in the flow direction P, the quantity f being smaller than the depth T of the structure elements (13), and T being the projection of the length L transversely with respect to the flow direction P.
26. 26. The flow channel according to claim 22 or 25, characterized in that individual structure elements (13) of a row (41) are not installed parallel and have an inactive to different flow angle.
27. 27. The flow channel according to claim 22, 25 or 26, characterized in that individual structure elements (13) of a row (42) have different lengths L1, L2.
28. 28. The flow channel according to one of the preceding claims, characterized in that opposite rows (17, 18, 19, 20) have a displacement f in the flow direction P, f being smaller than the depth T of a row (17, 19).
29. 29. The flow channel according to one of the preceding claims, characterized in that some or all of the structure elements (13, 13 ') of rows (17, 18, 19, 20, 21, 22) lying opposite one another are oriented opposite way, in particular they have an inactive to opposite flow angle.
30. 30. The flow channel according to one of the preceding claims, characterized in that the rows (23, 24) lying opposite one another have gaps (25, 26, 27) between the structure elements (13), with structural elements ( 13 ') of the other row in each case lying opposite these gaps.
31. 31 The flow channel according to one of the preceding claims, characterized in that the structure elements of opposite rows touch each other, in particular they are joined together by welding or melting.
32. 32. The flow channel according to one of the preceding claims, characterized in that the rows of elements of opposite structure have the same depth T in the flow direction P.
33. 33. The flow channel according to one of the preceding claims, characterized in that the rows of opposing structure elements have different depths T1, T2 in the flow direction P.
34. 34. The flow channel according to one of the preceding claims, characterized in that the heat exchanger surfaces are substantially opposite each other, and in particular the structure elements installed in them are curved.
35. 35. The flow channel according to one of the preceding claims, characterized in that the heat exchanger surfaces lying substantially opposite each other are primary surfaces or secondary heat engineering surfaces, the secondary surfaces being formed in particular by blades, nets or the like. similar that are clamped, welded or fused preferably to the flow channel.
36. 36. The flow channel according to one of the preceding claims, characterized in that the height h is in the range of 2 mm to 10 mm, in particular in the range of 3 mm to 4 mm, and is preferably approximately 3.7 mm.
37. 37. The flow channel according to one of the preceding claims, characterized in that the flow channel is rectangular and has a width b which is in particular in the range of 5 mm to 120 mm, preferably in the range of 10 mm to 50 mm .
38. 38. The flow channel according to one of the preceding claims, characterized in that a hydraulic diameter of the flow channel is in the range of 3 mm to 26 mm, in particular in the range of 3 mm to 10 mm.
39. 39. The flow channel according to one of the preceding claims, characterized in that at least one, in particular each row of structural elements comprises in each case a plurality of structural elements.
40. 40. A heat exchanger, in particular an exhaust gas cooler, in particular for a motor vehicle, having flow channels for a fluid, characterized in that at least one flow channel is designed as described in one of the claims precedents
41. 41 The heat exchanger according to claim 39, characterized in that the flow channels (1) are formed as welded or fused flat or rectangular tubes (7) and the heat exchanger surfaces (F1, F2) are formed as flat tube walls .
42. 42. The heat exchanger according to one of the preceding claims, characterized in that the flow channels are formed by applied plates or discs having structure elements on top of each one.
43. 43. The heat exchanger according to one of the preceding claims, characterized in that the structural elements (10, 1 1) are formed in the walls of the tube (F1, F2), in particular by stamping.
44. 44. The heat exchanger according to one of the preceding claims, characterized in that the exhaust gas can flow through the pipes (7) and a liquid coolant can flow around the pipes (7).
45. 45. The heat exchanger according to one of the preceding claims, characterized in that the rows (8, 9) of structural elements (10, 1 1) are at a distance s from each other in the direction of flow (7a) which increases from two to six times the length L of a structure element.
46. 46. The heat exchanger according to one of the preceding claims, characterized in that between the rows with structural elements (fluid 1) there are additional rows with structural elements projecting outwards to fluid 2.
47. 47. The heat exchanger according to claim 45, characterized in that the structure elements projecting outwards are support inlays, networks or elements and touch each other or are welded or fused to one another.
48. 48. The heat exchanger according to claim 45 or 46, characterized in that structural elements projecting outwards contribute to improving the heat transfer.