EP2267393B1 - Flow channel for heat exchanger - Google Patents

Description

The invention relates to a flow channel through which a medium can flow in a flow channel for a heat exchanger according to the preamble of patent claim 1.

Flow channels for heat exchangers are from a first medium, eg. B. flows through an exhaust gas or a liquid coolant and define this first medium against a second medium to which the heat of the first medium is to be transmitted, from. Such flow channels may be tubes with a round cross-section, rectangular tubes, flat tubes or disc pairs, in which two plates or letters are connected at the edge. Most often, the media that are in heat exchange with each other, different, z. B. flows in the pipes a hot, laden with soot particles exhaust gas, and on the outside of the exhaust pipes are flowed around by a liquid coolant, which has different heat transfer conditions on the inside and outside of the tubes result. It has therefore been proposed, in particular for exhaust pipes, To arrange on the inside of a V-shaped and diffuser-like arranged turbulence generator, which provide a turbulence of the flow and an improvement of the heat transfer on the exhaust side and at the same time prevent soot deposition. Such solutions for exhaust gas heat exchanger are apparent from the following documents of the applicant: EP-A 677 715 . DE-A 195 40 683 . DE-A 196 54 367 and DE-A 196 54 368 , These known exhaust gas heat exchanger have rectangular tubes made of stainless steel, which are composed of two half-shells welded together, in which the turbulence generator, so-called winglets are molded or embossed and arranged one behind the other. The winglet pairs of the two half shells are either in the longitudinal direction of the tubes, ie offset in the flow direction against each other ( DE 196 54 367 . DE 196 54 368 ) or facing each other ( DE 195 40 683 ) arranged.

In the DE-A 101 27 084 The applicant has proposed a heat exchanger, in particular a coolant / air cooler with flat tubes and corrugated fins, in which the flat sides of the flat tubes have a structure consisting of structural elements. The structural elements are elongated, V-shaped arranged in rows transverse to the coolant flow direction and transverse to the longitudinal axis of the tubes and act as a vortex generator to increase the heat transfer on the coolant side. The vortex generators are embossed in both opposite pipe walls and protrude inwards into the coolant flow. The rows of vortex generators on one flat tube side are offset in the flow direction from the rows on the other flat tube side. Thus, it is also possible to measure the inwardly projecting height of the vortex generator greater than half the clear width of the flat tube cross-section.

By the EP-A 1 061 319 has been known a flat tube for a motor vehicle radiator, which has on its flat sides a structure consisting of individual elongated, arranged in rows structural elements.

In this case, rows with differently oriented structural elements are arranged in the flow direction, so that the flow in the interior of the flat tube is deflected approximately in a zigzag shape. In particular, however, the rows are arranged with structural elements on a flat tube side in the flow direction offset from the rows of the opposite flat tube side. A row of structural elements thus faces a smooth area of the flat tube inner wall. The flow within the coolant tube is thus alternately influenced by the structural elements of one and the other flat tube side, but not simultaneously. This is to be avoided, inter alia, a blockage of the pipes. With regard to the heat transfer capability, there are still potentials here.

It is an object of the present invention to improve a flow channel and a heat exchanger of the type mentioned in terms of its heat transfer capacity, in particular to increase turbulence and vortex formation, the pressure loss should increase to an even more reasonable level.

This object is achieved by the features of claim 1. According to the invention it is provided that at least two rows of structural elements on substantially opposite heat transfer surfaces have an overlap with each other, such that a structural element of a heat transfer surface has an overlap with an opposing structural element on the opposite heat transfer surface, wherein the structural elements are elongate and rectangular in shape and have a straight longitudinal axis, and wherein the structural elements on one heat transfer surface are oppositely oriented with respect to the structural elements of the other heat transfer surface so that they have an opposite outflow angle and wherein the rows of structural elements on the one heat transfer surface are opposite Rows of the structural elements on the other heat exchanger surface in the flow direction offset si nd. At the same time, structural elements projecting from the one and the other heat exchanger surface and projecting into the flow channel enter the flow and cause a turbulence of the flow, which results in an improvement of the heat transfer on the inside of the flow channel. In addition, will - For example, in the case of exhaust gas flow - may prevent soot deposition. The pressure loss keeps within reasonable limits. The flow within the flow channel is thus disturbed simultaneously on both sides, ie both boundary layers are detached at the same time, which leads to a particularly strong turbulence. The opposing structural elements or rows of structural elements can also be on the outside of the flow channel - in the case of an exhaust gas cooler on the coolant side - are. Advantageous embodiments of the invention will become apparent from the dependent claims.

A row of structural elements is formed in the context of the present invention of one or more structural elements, which are arranged in the flow direction P substantially side by side. In particular, a row can thus also be formed by a single structural element, next to which, for example, no further structural elements are arranged.

The offset in the flow direction results in a lower pressure loss. If the opposing structures touch and are joined by welding or soldering, the strength can be increased. According to a further variant, the structural elements are not arranged at regular intervals in a row, but these rows have gaps, which in each case on the opposite side structural elements are opposite and thus "fill in" these gaps - in plan view. Also, the advantage of a lower pressure loss is achieved.

Between or next to the structural elements or between or within the "structural rows" (rows with structural elements) (as viewed in the direction of flow P) also knobs and / or webs can be pronounced outwardly or inwardly to achieve a "support" and thus an increase in strength. The vortex generating structures can also take over this function in whole or in part.

According to an advantageous embodiment, the substantially opposing heat transfer surfaces are primary heating surfaces. According to a variant, however, the heat transfer surfaces are heat-technical secondary surfaces, which are formed in particular by preferably welded to the flow channel, welded or jammed ribs, webs or the like.

According to an advantageous embodiment, the height h of the structural elements is in the range of 2 mm to 10 mm, in particular in the range of 3 mm to 4 mm, preferably by 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 structural element row each comprises a plurality of structural elements.

Advantageously, the aforementioned flow channels are provided as flat, round, oval or rectangular tubes of a heat exchanger, advantageously a Abgaswärmeübertragers. The arrangement of the structural elements according to the invention, ie advantageously their impression in the pipe inner walls brings an increase in performance of the heat exchanger with it. Particularly advantageous are the arranged in rows structural elements for exhaust gas heat exchanger, because in this case a soot deposition is avoided in the interior of the flat tubes. The exhaust pipes are surrounded on their outside by a coolant, which is taken from the coolant circuit of the exhaust gases ejecting the engine. It is also possible that the structures are also stamped in plates or slices to produce heat exchangers from them.

It is advantageous that the angle of attack β is in each case greater than the outflow angle α.

It is advantageous that the radius R is in the range of 1 to 10 mm, preferably in the range of 1 to 5 mm.

It is advantageous that the radii R1 and R2 are equal to the radius R.

It is advantageous that a row each has the same structural elements.

It is advantageous that a row each has different structural elements.

It is advantageous that individual structural elements are mirrored to each other and arranged in pairs at a distance a next to each other.

It is advantageous that individual or all structural elements are displaced parallel to one another and arranged in pairs transversely to the flow direction at a distance a.

It is advantageous that a distance a between two structural elements can be different within at least one row.

It is advantageous that the distance a is in the range of 0 to 8 mm.

The individual structural elements of a row are offset from one another in the flow direction P by an amount f, the amount f being smaller than the depth T of the structural elements and T being the projection of the length L transverse to the flow direction P.

It is advantageous that individual structural elements of a row are not arranged in parallel and have a different outflow angle α.

It is advantageous that individual structural elements of a row have different lengths L1, L2.

The opposing rows have an offset f in the flow direction P, where f is smaller than the depth T of a row.

In this case, individual or all structural elements of opposing rows are aligned opposite and have an opposite outlet angle α.

It is advantageous that the rows lying opposite one another have gaps between the structural elements, which in each case are opposite structural elements of the other row.

It is advantageous that the structural elements of opposite rows touch, in particular by welding or soldering are connected.

It is advantageous that opposite rows of structural elements have an equal depth T in the flow direction P.

It is advantageous that opposite rows of structural elements have different depths T1, T2 in the flow direction P.

It is advantageous that the substantially opposing heat transfer surfaces heat-technical primary surfaces or secondary surfaces, the secondary surfaces are formed in particular by preferably soldered to the flow channel, welded or jammed ribs, webs or the like.

It is advantageous 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, preferably by 3.7 mm.

It is advantageous 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.

It is advantageous 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.

It is advantageous that at least one, in particular each structural element row each comprise a plurality of structural elements.

It is advantageous that the flow channels are designed as soldered or welded flat or rectangular tubes and the heat transfer surfaces as flat tube walls.

It is advantageous that the flow channels are formed by stacking plates or disks having structural elements.

It is advantageous that the structural elements are molded into the tube walls, in particular stamped.

It is advantageous that the pipes can be flowed through by exhaust gas and can be flowed around by a liquid coolant.

It is advantageous that the rows of structural elements in the flow direction have a distance s which contributes 2 to 6 times the length L of a structural element.

It is advantageous that there are further rows of structural elements between the rows of structural elements which project outwardly into the fluid two.

It is advantageous that the outwardly pronounced structural elements are supporting nubs, webs or elements and touch or soldered or welded together.

It is advantageous that the outwardly pronounced structural elements contribute to improving the heat transfer.

Fig. 1

einen Strömungskanal gemäß Stand der Technik,

Fig. 2a, b, c

einen Querschnitt von Strömungskanälen, einer

Fig. 3

ein Flachrohr mit einer Struktur,

Fig. 4

eine Halbschale des Flachrohres gemäß Fig. 3,

Fig. 5a, b, c, d

verschiedene Strukturelemente,

Fig. 6a, b, c, d, e, f, g, h

Strukturen auf Strömungskanälen,

Fig. 7a, b

weitere Strukturen,

Fig. 8

eine weitere Struktur,

Fig. 9a, b, c, d

gespiegelte Strukturelemente,

Fig. 10a, b, c, d

parallel verschobene Strukturelemente,

Fig. 11a, b, c, d

Reihen von Strukturelementen mit Abwandlungen und

Fig. 12a, b

weitere Strukturelemente.

Embodiments are illustrated in the drawings and will be described in more detail below. Show it

Fig. 1

a flow channel according to the prior art,

Fig. 2a, b, c

a cross section of flow channels, a

Fig. 3

a flat tube with a structure,

Fig. 4

a half-shell of the flat tube according to Fig. 3 .

Fig. 5a, b, c, d

different structural elements,

6a, b, c, d, e, f, g, h

Structures on flow channels,

Fig. 7a, b

further structures,

Fig. 8

another structure,

Fig. 9a, b, c, d

mirrored structural elements,

Fig. 10a, b, c, d

parallel shifted structural elements,

Fig. 11a, b, c, d

Rows of structural elements with variations and

Fig. 12a, b

further structural elements.

Fig. 1 shows a simplified representation of a flow channel 1, which is designed as a rectangular tube, a rectangular inlet cross section 2, two opposite flat sides F1, F2 and two opposite narrow sides S1, S2 has. The channel 1 is from a flow medium, for. B. flows through an exhaust gas in the direction of the arrow P. On the lower flat side F2 arranged V-shaped vortex generators 3a, 3b, 4a, 4b, which cause by generating vortices an increased turbulence of the flow and at the same time - with an exhaust gas flow - prevent soot deposition. This representation corresponds to the aforementioned prior art. Thereafter, the paired V-shaped exhibited, in the flow direction diffuser-like expanding vortex generators 3a, 3b and 4a, 4b are also referred to as winglets.

Fig. 2a shows the cross section of a formed as a flat tube flow channel 1, in which both on the upper flat side F1 and on the flat side F2 winglet pairs 5a, 5b and 6a, 6b are arranged. The channel cross-section has a channel height H and a channel width b. The winglets 5a, 5b, 6a, 6b have a height h projecting into the channel cross-section. This arrangement of winglets corresponds to the aforementioned prior art. The designations F1, F2 also apply to the following exemplary embodiments.

Fig. 2b shows the cross section of a round tube formed as flow channel 1 ', in which both on the upper flat side F1 and on the lower flat side F2 structural elements 13' and 13 are arranged. The channel cross section has a channel height H.

Fig. 2c shows the cross section of a formed as a flat tube flow channel 1, in which the Wärmeübertragunosflächen F1, F2 thermally represent secondary surfaces, as they do not transfer heat directly from one to the other medium. The heat transfer surfaces have structural elements 13, 13 '.

Fig. 3 shows a flow channel, which is formed as a flat tube 7, which is partially shown in a plan view. The flat tube 7 has a longitudinal axis 7a, a width b and two rows 8, 9 of V-shaped arranged structural elements or winglets 10, 11 which are each embossed both in the top F1 and in the bottom F2 of the flat tube 7, and with the same pattern, so that the top winglet row covers the underlying row. There are eight winglets in a row, evenly distributed over the entire width b, but six or seven winglets may be the same width. For narrow tubes, discs or plates, the number of winglets may also be below six, with wider tubes or discs / plates also above eight. The two rows 8, 9 have a distance s to each other, which is measured from center to center and is about 2 times to 6 times the length of the winglets. Between the individual rows, therefore, there is a smooth area in each case, into which, for example, support structures are embossed. The rows of winglets extend over the entire length of the flat tube 7, in each case with the distance s, on both sides of the flat tube 7.

Fig. 4 shows a bottom half shell 7b of the flat tube 7 in a view in the direction of the longitudinal axis 7a of the flat tube 7. The half shell 7b, has a bottom F2 and two lateral legs 7c, 7d, wherein on the bottom or the bottom F2 winglets 11 'arranged , ie are imprinted in the pipe wall. The upper half shell is not shown; it is mirror-inverted and is longitudinally welded to the lower half-shell 7b on the lateral legs 7c, 7d. The winglets 11 'have a height h, with which they protrude into the clear cross-sectional area of the flat tube 7. The tube can also be made from a sheet that is formed and welded on one side.

In a preferred embodiment, the width b of the flat tube is 40 mm or 20 mm, the overall height of the flat tube about 4.5 mm and the height h of the winglets about 1.3 mm. With a clear channel height of 4.0 mm, a clear cross-sectional height of 1.4 mm for a core flow remains as a result of the winglets projecting from both sides into the channel cross-section, each with a height of 1.3 mm. The distance s of the rows is about 20 mm.

The flat tube 7 is preferably used for per se known exhaust gas heat exchanger (not shown), ie it is traversed on the inside of exhaust gas of an internal combustion engine of a motor vehicle and cooled on its outside by coolant of a coolant circuit of the internal combustion engine. In this case, the outside of the flat tubes 7 - as known from the prior art - be smooth and be kept for example by embossed knobs at a distance with adjacent tubes. However, it is also possible to provide on the outside of the flat tubes 7 fins to improve the heat transfer on the coolant side.

The Figures 5a, 5b, 5c and 5d show individual structural elements that are provided for a structure on the flow channels.

Fig. 5a shows an elongated structural element 13 with a longitudinal axis 13a, which forms with a reference line q an angle a, the outflow angle. The flow direction for all representations 5a to 5d is the same in each case and represented by an arrow P. The reference line q is perpendicular to the flow direction P. The structural element 13 has a length L and a width B. The latter can be constant or variable, ie increasing in the direction P.

Fig. 5b shows an elongated, but angled structural element 14 with two mutually inclined longitudinal axes 14a, 14b, which enclose with the reference line q each have an angle α and β. β is referred to here as the angle of attack and α as the outflow angle. The flow according to the arrow P is thus deflected in two stages, ie initially only slightly and then stronger. This results in a lower pressure drop - compared to a structural element according to Fig. 5a at the same outlet angle α. The length of the structural element 14 along the longitudinal axes 14a, 14b is denoted by L.

Fig. 5c shows an arcuate structural element 15 with a curved longitudinal axis 15a, which corresponds to a circular arc with the radius R. The upstream angle is referred to as the angle of attack β and the downstream angle is referred to as the outflow angle α. Again, there is a gentle deflection of the flow around the angle (90 ° - β) and then a stronger deflection around the angle (90 ° - α). As a result of this continuously increasing deflection of the flow, a lower pressure loss is likewise achieved-in comparison to the structural element 13 according to FIG Fig. 5a , The length of the structural element 15 along the longitudinal axis 15a is denoted by L.

Fig. 5d shows a further embodiment of a structural element 16. which is approximately Z-shaped and also has a Z-shaped extending longitudinal axis 16a. The longitudinal axis 16a connects two circular arc pieces of different curvature, but with the same radius R1 = R2. The angle of attack is here denoted by β, the outflow angle by α, it corresponds to a flow deflection of (90 ° - α), which takes place in the central region of the structural element 16. The inflow and outflow of this structural element takes place practically in the flow direction P. This is a particularly low-pressure deflection of the flow given. The length of the structural element along the longitudinal axis 16a is denoted by L.

The Fig. 6a, 6b . 6c, 6d . 6e, 6f . 6g . 6h show arrangement patterns of the structural elements 13 according to FIG Fig. 5a , in rows on a section of a flow channel. In embodiments not shown, only individual structural elements are opposite each other.

Fig. 6a shows the elongated structural elements 13 each arranged in two rows 17, 18, which have a distance s in the flow direction P. The structural elements 13 shown in solid lines are impressed in the upper side F1 of the flow channel. In the lower heat exchanger surface or side F2 of the flow channel broken structure elements 13 ', also in rows 19, 20 are arranged. The rows are shown by dashed lines. The structural elements 13 'on the lower surface F2 are opposite to the structural elements 13 on the upper surface F1 aligned, ie they have an opposite outflow angle α (see. Fig. 5a ) on. In addition, the rows 19, 20 offset from the rows 17, 18 in the flow direction P, by the amount f. The structural 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 offset f is smaller than the depth T, so that between the rows 18, 20 and 17, 19 an overlap Ü remains, which is from the difference of T and f. An overlap Ü of 100% for rows of equal depth T means that the offset is zero (f = 0). In the case of rows with different depths T1 or T2, for example T1 <T2, an overlap of 100% means that the overlap Ü is equal to the smaller depth T1 (U = T1). By an offset of each opposing rows 17, 19 and 18, 20 results in a lower pressure loss than in rows without offset.

Fig. 6b shows another pattern of in-line structure elements 13 in a row 21 and a row 22 with different outflow angles α (not shown). The structural elements 13 in solid lines are embossed in the upper side F1 of the flow channel. On the lower surface F2 of the flow channel are in the flow direction P, dashed at the same height illustrated structural elements 13 'arranged with opposite orientation, so that an upper structural element 13 and an opposite lower structural element 13' in the plan view in each case appear as a cross. The upper row with structural elements 13 is thus not offset from the lower row with structural elements 13 '; the overlap Ü is 100%.

Fig. 6c to Fig. 6h show further arrangement patterns of the structural elements 13, 13 'on the upper (shown in solid) and the lower (shown broken) side F1, F2 of the flow channel.

Fig. 6h also shows on the outside of the flow channels supporting elements 13 ", which are arranged in this embodiment adjacent to the structural elements 13, 13 'and in particular within the rows formed by the structural elements 13, 13' For a desired support of the respective flow channel, the support elements 13 "advantageously have a height which is desired Distance between two flow channels or between the respective flow channel and a housing wall of a heat exchanger corresponds.

The FIGS. 7a and 7b show further variants for the arrangement of the structural elements 13 in rows,

Fig. 7a shows a section of a flow channel with two rows 23, 24 of V-shaped arranged structural elements 13 on the upper side F1. The structural elements 13 are not arranged at constant intervals next to each other, but instead have gaps 25, 26, 27, but are filled on the underside F 2 by structural elements 13 ', so that in the plan view a continuous uniform arrangement of structural elements 13 and 13 'results. This arrangement of "discontinuous" rows 23, 24 and the corresponding rows on the bottom results in a lower pressure drop for the flow in the direction P, because the structural elements - seen in the width direction - only alternately engage from above and below in the flow.

Fig. 7b shows a similar patchy arrangement of parallel-aligned structural elements 13 on the upper side F1 in rows 28, 29. The gaps between the structural elements 13 are in turn filled by structural elements 13 'on the underside F2, wherein the structural elements 13 on the upper side F1 and the structural elements 13 'on the bottom F2 to complement a zig-zag arrangement in the plan view. This arrangement is relatively low pressure.

Fig. 8 shows a further embodiment for the arrangement of structural elements 13 and 13 'in two rows 30, 31 on the upper side F1. The structural elements 13 of the row 30 and the structural elements 13 'of the opposite row (on the bottom F2) are parallel and in the same Spaced apart. The same applies analogously to the second row 31, wherein only the outflow angle is opposite, so that, as seen in the direction of flow P, a deflection of the flow results.

In the FIGS. 6a, 6b . 7a, 7b and 8th In each case, structures with the structural elements 13 were obtained according to FIG Fig. 5a shown. The structural elements 13 can also be replaced by structural elements 14 (in FIG Fig. 5b ), 15 ( Fig. 5c ) or 16 ( Fig. 5d ) be replaced. It would also be possible in a number of different structural elements, eg. B. 13 and 14 to use.

Fig. 9a, 9b, 9c, 9d show variants of the structural elements 13, 14, 15, 16 by mirroring: This results in so-called winglet pairs 32, 33, 34, 35, wherein in each case a minimum distance a is provided between two structural elements. The flow direction is usually in the direction of the arrow P, wherein the flow of the winglet pairs traditionally takes place at the narrowest point a. This results in decreasing pressure losses for the different winglet pairs 32 to 35 in this order. These winglet pairs can be arranged side by side in rows, e.g. B. as in the FIGS. 6 to 8 ,

10a, 10b, 10c, 10d show further variations of the structural elements 13, 14, 15, 16 by parallel displacement. This results in double elements 36, 37, 38, 39, each with equal distances a at the arrival and downstream, z. B. in the structures according to Fig. 6 to 8 can be integrated.

It is important that the structural elements of a series above and / or below not necessarily have the same geometric shape or dimensions, as exemplified by four structural elements in Fig. 11a will be shown. Rather, as in Fig. 11b shown, the structural elements are arranged with an offset f in the flow direction P.

In Fig. 11c vary the outflow angle of the structural elements 13, and in Fig. 11d vary the lengths L1, L2 of the structural elements 13. A combination (not shown) of the variants according to Fig. 11b, 11c, 11d is also possible. These variations can also occur in the upper and / or lower surface F1 or F2.

Fig. 12a shows another structural element 43, which is formed as an angle with two straight legs 43a, 43b, which are connected at their apex by an arc 43c. In this respect, this structural element 43 constitutes a modification of the winglet pair 32 Fig. 9a The flow is preferably in the direction of vertex 43c, according to the arrow P.

Fig. 12b shows a further modification of the structural element pair 34 according to Fig. 9c namely, a structural member 44 having two arcuate legs 44a, 44b joined at apex by a bend 44c. The structural element 44, which is likewise flown in the direction of the apex 44c in accordance with the arrow P, initially causes a small flow deflection, which then amplifies due to the legs 44a, 44b curved into the flow.

The elements according to Fig. 12a and Fig. 12b can be used in all previously shown arrangements where two structures arranged in V-shape can be found again.

Claims (8)

1. A flow passage (1), through which a medium can flow in a direction of flow P, for a heat exchanger having two heat exchanger surfaces (F1, F2), which lie substantially opposite one another, are in particular arranged parallel and/or at a spacing of a passage height H and each have a structure formed from a plurality of structure elements that are arranged next to one another in rows transversely with respect to the direction of flow P and project into the flow passage, wherein the structure elements each have a width B, a length L, a height h, a flow off angle α and a longitudinal axis, wherein at least two rows (17, 18, 19, 20) with structure elements (13, 13') on substantially opposite heat exchanger surfaces (F1, F2) have an overlap (Ü) with one another, such that a structure element of a heat exchanger surface overlaps with an opposite structure element of the opposite heat exchanger surface, wherein the structure elements (13) are elongate and rectangular in form and have a straight longitudinal axis (13a), characterised in that the structure elements (13') on the one heat exchanger surface (F2) are arranged opposite to the structure elements (13) of the other heat exchanger surface (F1), so that they have an opposite flow-off angle α and in that the rows of the structure elements on the one heat exchanger surface (F2) are offset in the flow direction opposite the rows of the structure elements on the other heat exchanger surface (F1).
2. The flow passage as claimed in claim 1, characterised in that the height h of at least one of the structure elements (13, 14, 15, 16) is 20% to 50% of the passage height H.
3. The flow passage as claimed in claim 2, characterised in that the length L of at least one structure element (13, 14, 15, 16) is from 2 to 12 times the height h of the structure element.
4. The flow passage as claimed in one of claims 1 to 3, characterised in that the distance s between the rows amounts to 0.5 to 8 times the depth T.
5. The flow passage as claimed in one of claims 1 to 4, characterised in that the distance s between in each case two rows varies in the direction of flow P.
6. The flow passage as claimed in one of claims 1 to 4, characterised in that at least one structure element (13, 14, 15, 16) has a constant width B in the range from 0.1 to 6.0 mm, preferably in the range from 0.1 to 3.0 mm.
7. The flow passage as claimed in one of claims 1 to 4, characterised in that at least one structure element (13, 14, 15, 16) has a width which increases in the direction of flow between a starting width B1 and a finishing width B2, wherein the starting width B1 is in the range from 0.1 to 4 mm and the finishing width B2 is in the range from 0.1 to 6 mm.
8. The flow passage as claimed in one of the preceding claims, characterised in that the flow off angle α is in the range from 20 to 70 degrees, preferably in the range from 40 to 65 degrees, and in particular has a value of from 50 to 60 degrees.

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