US20240167773A1

US20240167773A1 - Corrugated fin for heat exchanger

Info

Publication number: US20240167773A1
Application number: US18/509,913
Authority: US
Inventors: Wolfgang Seewald; Falk Viehrig; Regina Zeiler
Original assignee: Mahle International GmbH
Current assignee: Mahle International GmbH
Priority date: 2022-11-18
Filing date: 2023-11-15
Publication date: 2024-05-23
Also published as: CN118057112A; DE102022212358A1

Abstract

A method for producing a corrugated fin for a heat exchanger. Providing a gill structure having a plurality of longitudinally shaped gills arranged grid-like relative to one another is provided and the corrugated fin is produced in this manner on a fin sheet of corrugated design which can be flowed through by a fluid, in particular a gas, along a flow direction. The gills are arranged on the fin sheet in the form of a plurality of grid lines and grid columns so that the individual grid line (RZ) extend parallel to the flow direction and the individual grid columns perpendicularly to the flow direction and the individual gills additionally extend each along an extension direction and have a gill depth measured along the extension direction. The individual gills of a respective grid line are arranged following one another with a predetermined fin density perpendicularly to the flow direction so that the flow direction and the extension direction are arranged at an acute gill angle relative to one another.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. 10 2022 212 358.1, filed Nov. 18, 2022, the entirety of which is hereby fully incorporated by reference herein.
The invention relates to a corrugated fin for a heat exchanger and to a heat exchanger having at least one such corrugated fin.
In heat exchangers with air as heat transfer fluid it is important to realise a high performance density with as low as possible a pressure drop on the air side. In particular in exchangers installed in motor vehicles it is necessary for saving installation space and for achieving as low as possible a net weight to realise high performance densities also with respect to the air-side pressure drop.
Before this background, US 2005/0045314 A1 describes fins for a heat exchanger, in which a corrugated fin sheet arranged between flat tubes is provided with gills to improve the heat transfer.
In DE 10 2009 021 179 A1, advantageous values for a gill angle and a gill depth of the gills arranged on the fin sheet are stated.
It is the object of the present invention to create a method for producing a heat exchanger, which is characterised in the transfer of heat by an improved performance efficiency with low pressure drop of the heat exchanger fluid when flowing through the heat exchanger. A further object of the invention consists in creating a corrugated fin which has the said characteristics.
This object is solved through the subject of the independent patent claims. Preferred embodiments are subject of the dependent patent claims.
The basic idea of the present invention is based on the realisation gained through different experimental investigations and simulation calculations that the optimal gill angle, at which the individual gills of the corrugated fin decreases with increasing fin density relative to a flow direction with which air is conducted through the corrugated fin.
A particularly high performance density in conjunction with a low pressure drop at the same time arises when gills on the corrugated fin are configured so that they satisfy the following relationship in terms of their arrangement and orientation on the surface of the fin sheet:
KW=β=arctan((1/RD)/(2*KT))
Here, KW or β is an intermediate angle formed between the flow direction DR of the corrugated fin and the extension direction of the individual gills, which in the following is also referred to as gill angle.
Apart from this, RD is fin density of the fin according to the invention. As fin density RD, a number of fin flanks per length unit is determined, which follow one another along a length direction of the fin in the corrugated fin sheet of the corrugated fin. Furthermore, KT is a gill depth of the gills measured along the extension direction.
In detail, the corrugated fin according to the invention includes for a heat exchanger a fin sheet of corrugated configuration which, along a flow direction, can be flowed through by a fluid, in particular a gas, on which fin sheet a gill structure with a plurality of longitudinally shaped gills is arranged in a grid-like manner relative to one another. The gill structure with the gills comprises a plurality of grid lines and grid columns, wherein the individual grid lines extend parallel to the flow direction and the grid columns perpendicularly to the flow direction. The individual gills extend each along an extension direction and have a gill depth each measured along the extension direction. In the simplest case, four gills are provided, wherein the grid-like arrangement is formed by two grid lines and two grid columns. Preferably, more than four gills and thus more than two grid columns and grid lines are provided. Furthermore, the individual gills of a respective grid line are arranged following one another with a predetermined fin density along a longitudinal direction of the fin. The flow direction and the extension direction are arranged at an acute gill angle to one another. According to the invention, the gills of the gill structure are arranged relative to one another so that the following gill relationship concerning distance and orientation of the gills relative to one another is substantially satisfied.
KW=β=arctan((1/RD)/(2*KT)),
wherein KT is the gill depth and RD the fin density as defined or determined above.
In a preferred embodiment, the individual gills are arranged relative to one another so that at least one (first) gill arranged in a certain grid line is arranged in a virtual extension along the extension direction of a (second) gill, which is arranged in a grid column next to but one relative to the determined grid column with the first gill.
In a preferred embodiment of the corrugated fin according to the invention, the fin density RD is more than 110 Ri/dm.
In another preferred embodiment of the corrugated fin according to the invention, the gill depth KT is at least 1.1 mm.
Particularly practically, a material thickness of the fin sheet is between 0.05 mm and 0.1 mm.
According to an advantageous further development of the invention, a first gill structure and a second gill structure can be provided. In this further development, the gill angles of the two gill structures have different offset orientations.
Further, the invention relates to a heat exchanger having multiple first and second fluid paths alternately following one another along a stack direction which are fluidically separated from one another for being flowed through by a first and second fluid. In at least one first fluid path, preferentially in multiple first fluid paths, particularly preferably in all first fluid paths of the heat exchanger a corrugated fin according to the invention introduced above is arranged, so that the advantages of the corrugated fin according to the invention introduced above apply to the heat exchanger according to the invention.
The heat exchanger according to the invention can be employed in a heating element, coolant cooler, oil-air cooler, evaporator, condenser, gas cooler, charge air cooler, each in particular for a motor vehicle.
In a preferred embodiment of the heat exchanger according to the invention, the at least one corrugated fin supports itself on two boundary elements located opposite one another in the stack direction and delimiting the first fluid path with the corrugated fin arranged therein.
Further, the invention relates to a method for producing a corrugated fin according to the invention introduced above, so that the advantages of the corrugated fin according to the invention introduced above apply to the method according to the invention.
With the method according to the invention, a gill structure with a plurality of longitudinally shaped gills oriented grid-like relative to one another is arranged on a fin sheet of corrugated design and which can be flowed through along a flow direction by a fluid, in particular a gas, and the corrugated fin with such a gill structure produced in this way. In the simplest case, four gills are provided, however preferably more than four gills.
The gills are arranged on the fin sheet in the form of a plurality of grid lines and grid columns so that the individual grid lines extend parallel to the flow direction and the individual grid columns extend perpendicularly to the flow direction and apart from this the individual gills each extend along an extension direction and have a gill depth measured along the extension direction.
In the simplest case, four gills are provided, wherein the grid-like arrangement is formed by two grid columns and two grid lines. However, more than four gills and thus more than two grid columns and grid lines are preferably provided. Apart from this, the individual gills of a respective grid line are arranged following one another with a predetermined fin density along the longitudinal direction, wherein the flow direction and the extension direction are arranged at an acute gill angle relative to one another. Apart from this, the individual gills are arranged and oriented relative to one another so that the following “gill relationship” is substantially satisfied:
KW=β=arctan((1/RD)/(2*KT))
Here, KW or β is an intermediate angle formed between the flow direction DR of the corrugated fin and the extension direction ER of the gills, which in the following is also referred to as gill angle KW. Apart from this, RD is the fin density defined above—preferably in quantity per dm—and KT the gill depth of the individual gills measured along the extension direction.
Here “substantially” is to mean that an actually realised angle β* can deviate by up to +/−3º, preferentially by up to +3°/−1° from the gill angle KW calculated by means of the “gill relationship” β=arctan ((1/RD)/(2*KT)).
In a preferred embodiment, the individual gills during the course of the production of the corrugated fin are arranged and oriented relative to one another so that at least one (first) gill arranged in a defined grid line is arranged in a virtual extension along the extension direction of a (second) gill, which is arranged in a grid column next to but one relative to the determined grid column with the first gill.
Particularly preferably, the gill structure can be provided with a fin density of more than 110 Ri/dm.
Practically, gills with a gill depth of at least 1.1 mm can be provided.
Further important features and advantages of the invention are obtained from the subclaims, from the drawings and from the associated figure description by way of the drawings.
It is to be understood that the features mentioned above and still to be explained in the following cannot only be used in the respective combination stated but also in other combinations or by themselves without leaving the scope of the present invention.
Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein same reference numbers relate to same or similar or functionally same components.

It shows, in each case schematically:

FIG. 1 in a part representation a lateral view of a heat exchanger according to the invention, which is produced by means of the method according to the invention,

FIG. 2 an extract of an individual corrugated fin shown in FIG. 1 ,

FIG. 3 a section through a part of the fin in which individual gills of the gill structure present on the fin sheet are noticeable.

FIG. 1 shows in a part representation and in a lateral view an example of a heat exchanger 10 according to the invention, which was produced by means of the method according to the invention. The heat exchanger 10 exemplarily shown in FIG. 1 is part of a heating element for a motor vehicle. The heat exchanger 10 includes multiple first and second fluid paths 11 a, 11 b alternately following one another and which are fluidically separated from one another for being flowed through by a first and second fluid F1, F2 respectively. The second fluid paths 11 b are delimited by tubular bodies 13, which are arranged spaced apart from one another along the stack direction SR. The intermediate spaces 14 between two tubular bodies 13 adjacent in the stack direction SR form the first fluid paths 11 a, so that the two tubular bodies 13 delimiting the respective intermediate space 14 form the boundary elements 12 for the first fluid path 11 a in the stack direction SR. In the first fluid paths 11 a, a corrugated fin 1 according to the invention each is arranged, which is explained in more detail in the following.
Each of the corrugated fins 1 according to FIG. 1 supports itself on the two boundary elements 12 delimiting the respective first fluid path 11 a with the corrugated fin 1 arranged therein in the stack direction SR. In the exemplary scenario, a fin depth RT of the corrugated fin 1 measured along the flow direction DR is between 15 mm and 80 mm, preferably between 15 mm and 55 mm.
FIG. 2 shows an extract of an individual corrugated fin 1 of FIG. 1 . Accordingly, the corrugated fin 1 includes a fin sheet 2 of corrugated configuration which can be flowed through along a flow direction DR by the first fluid F1, for example by air.
The flow direction DR extends perpendicularly to the stack direction SR. In the FIGS. 1 and 2 , the flow direction DR extends perpendicularly to the drawing plane. A longitudinal direction LR of the corrugated fin 1 extends in the drawing plane from the left to the right, i.e. along a longitudinal extend of the tubular body 13. The longitudinal direction LR extends perpendicularly both to the stack direction SR and also to the flow direction DR.
On the surfaces 5 noticeable in FIG. 2 of the fin flanks 7 of the fin sheet 2 shown in FIG. 1 , a gill structure 3 each is arranged. The number of the gill flanks 7 per length unit in the longitudinal direction is defined as fin density RD (unit: Ri/dm). Practically, a material thickness D of the fin sheet 2 is between 0.05 mm and 0.1 mm.
FIG. 3 shows a section along a viewing direction BR perpendicularly to the surface 5. Accordingly, the gill structure 3 includes a plurality of longitudinally shaped gills 4 arranged grid-like relative to one another. The gills 4 are formed as raised break-through of the fin sheet 2 and arranged behind one another in a depth direction TR, which is identical to the flow direction DR. In FIG. 3 , only six such gills 4 are shown for the sake of clarity, which form a grid having two grid lines RZ and three grid columns RS.
The individual gills 4 are each formed longitudinally shaped and extend in each case along an extension direction ER. According to the FIGS. 2 and 3 , the gills 4 are formed as series of webs directly following one another in the depth direction TR, i.e. formed by means of webs which are each separated from one another and angled by means of only one incision each of the fin sheet 2. The raising angle relative to the depth direction TR, i.e. the intermediate angle between the depth direction TR or flow direction DR and the extension direction ER is defined as gill angle KW. The entire length of a gill 4, measured along the extension direction ER and in a plane with the depth direction TR, is defined as gill depth KT. The gill depth KT of the corrugated fins 1 in the example is at least 1.1 mm each.
According to FIG. 3 , the gills 4 are formed on the fin sheet 2 so that the flow direction DR and the extension direction ER form an acute angle relative to one another—in the following also referred to as gill angle KW or β.
According to FIG. 3 , the individual gills 4 are arranged relative to one another so that at least one first gill 4, 4 a arranged in a defined grid column RS, RS.1 is arranged in a virtual extension V along the extension direction ER of a second gill 4, 4 b, which is arranged in a grid column RS, RS.2 next but one relative to the certain grid column RS, RS.1 with the first gill 4.
The gills 4 of the gill structure 3 are arranged relative to one another so that the following gill relationship concerning distance and orientation of the gills 4 to one another is substantially satisfied:
KW=β=arctan((1/RD)/(2*KT))
KT is the gill depth of the gills 4 and RD the fin density of the corrugated fin 1. In the exemplary scenario, the fin density RD is more than 110 Ri/dm.
The “gill relationship” is obtained from the variables B, a and b drawn in the FIG. 3 from the following geometrical relationship:
tan KW=tan β=b/a (Equation 1)
From this it follows
KW=β=arctan(b/a) (Equation 2)
With b=1/RD and a=2*KT the gill relationship
KW=β=arctan((1/RD)/(2*KT))
results from this.
In the exemplary scenario, an actually realised angle β* of at least one gill 4 can deviate by up to +/−3°, preferentially by up to +3º/−1° from the gill angle KW calculated by means of the above relationship.
The specification can be readily understood with reference to the following Numbered Paragraphs:

- Numbered Paragraph 1. A corrugated fin (1) for a heat exchanger,
  - having a fin sheet (2) of corrugated configuration which, along a flow direction (DR) can be flowed through by a (first) fluid (F1), in particular a gas, on which fin sheet (2) a gill structure (3) with a plurality of in each case longitudinally shaped gills (4) are arranged in a grid-like manner relative to one another,
  - wherein the gill structure (3) with the gills (4) includes a plurality of grid lines (RZ) and grid columns (RS) wherein the individual grid lines (RZ) extend parallel to the flow direction (DR) and the individual grid columns (RS) perpendicularly to the flow direction (DR),
  - wherein the individual gills (4) each extend along an extension direction (ER) and each have a gill depth (KT) measured along the extension direction (ER),
  - wherein the individual gills (4) of a respective grid line (RZ) are arranged with a predetermined fin density (RD) following one another perpendicularly to the flow direction (DR),
  - wherein the flow direction (DR) and the extension direction (ER) are arranged at an acute gill angle (B) relative to one another,
  - wherein the individual gills are arranged relative to one another so that the following gill relationship is substantially satisfied:

β=arctan((1/RD)/(2*KT)).

- Numbered Paragraph 2. The corrugated fin according to Numbered Paragraph 1, characterised in that the individual gills (4) are arranged relative to one another so that at least one (first) gill (4, 4 a) arranged in a certain grid column (RZ, RZ.1) is arranged substantially in a virtual extension (V) along the extension direction (ER) of a (second) gill (4, 4 b), which is arranged in a grid column (RS, RS.2) next but one relative to the defined grid column (RS, RS.1) with the first gill (4, 4 a).
- Numbered Paragraph 3. The corrugated fin according to Numbered Paragraph 1 or Numbered Paragraph 2,
  - characterised in that
  - the fin density (RD) is more than 110 Ri/dm.
- Numbered Paragraph 4. The corrugated fin according to any one of the Numbered Paragraphs 1 to 3,
  - characterised in that the gill depth (KT) is at least 1.1 mm.
- Numbered Paragraph 5. The corrugated fin according to any one of the preceding Numbered Paragraphs,
  - characterised in that
  - a material thickness (D) of the fin sheet (2) is between 0.05 mm and 0.1 mm.
- Numbered Paragraph 6. The corrugated fin according to any one of the preceding Numbered Paragraphs,
  - characterised in that
  - a fin depth (RT) of the fin (1) measured in the flow direction (DR) is between 15 mm and 80 mm, in particular between 15 mm and 55 mm.
- Numbered Paragraph 7. A heat exchanger (10) in particular for a motor vehicle,
  - having multiple first and second fluid paths (11 a, 11 b) alternately following one another along a stack direction (SR) which are fluidically separated from one another for being flowed through by a first and second fluid (F1, F2) respectively,
  - wherein in at least one first fluid path (11 a), preferentially in multiple first fluid paths (11 a), particularly preferably in all fluid paths (11 a), a corrugated fin (1) according to any one of the preceding Numbered Paragraphs is arranged.
- Numbered Paragraph 8. The heat exchanger according to Numbered Paragraph 7, characterised in that the at least one corrugated fin (1) supports itself on two boundary elements (12) located opposite one another in the stack direction (SR) and delimiting the first fluid path (11 a) with the corrugated fin arranged therein.
- Numbered Paragraph 9. A method for producing a corrugated fin (1) according to any one of the Numbered Paragraphs 1 to 6,
  - according to which on a fin sheet (2) of corrugated design and which can be flowed through along a flow direction (DR) by a (first) fluid (F1), in particular a gas, a gill structure (3) having a plurality of longitudinally shaped gills (4) arranged grid-like relative to one another, is provided,
  - wherein the gills (4) are arranged with a plurality of grid lines (RZ) and grid columns (RS) so that the individual grid lines (RZ) extend parallel to the flow direction (DR) and the individual grid columns (RS) perpendicularly to the flow direction (DR), and in addition the individual gills (4) each extend along an extension direction (ER) and have a gill depth (KT) measured along the extension direction (ER),
  - wherein the individual gills (4) of a respective grid line (RZ) are arranged with a predetermined fin density (RD) following one another perpendicularly to the flow direction (DR), so that the flow direction (DR) and the extension direction (ER) are arranged at an acute gill angle (3) relative to one another,
  - wherein the individual gills (4) are arranged relative to one another so that the following gill relationship is substantially satisfied:

β=arctan((1/RD)/(2*KT)),

- - wherein KT is the gill depth and RD the gill density.
- Numbered Paragraph 10. The method according to Numbered Paragraph 9, characterised in that an actually realised angle β* of at least one gill preferentially deviates by up to +/−3°, preferentially by up to +3°/−1° from the gill relationship β=arctan ((1/RD)/(2*KT)).
- Numbered Paragraph 11. The method according to either Numbered Paragraph 9 or Numbered Paragraph 10,
  - characterised in that
  - the individual gills (4) are arranged and oriented relative to one another so that at least one (first) gill (4, 4 a) arranged in a certain grid line (RZ, RZ.1) is substantially arranged in a virtual extension (V) along the extension direction (ER) of a (second) gill (4, 4 b) which is arranged in a grid column (RS, RS.2) next but one relative to the certain grid column (RS, RS.1) with the first gill.
- Numbered Paragraph 12. The method according to any one of the Numbered Paragraphs 9 to 11,
  - characterised in that
  - a fin density (RD) of more than 110 Ri/dm is provided.
- Numbered Paragraph 13. The method according to any one of the preceding Numbered Paragraphs 9 to 12,
  - characterised in that
  - the gills (4) are provided with a gill depth (KT) of at least 1.1 mm.

Claims

1. A corrugated fin for a heat exchanger, comprising

a fin sheet of corrugated configuration which along a flow direction (DR) can be flowed through by a first fluid, in particular a gas, on which fin sheet a gill structure with a plurality of in each case longitudinally shaped gills are arranged in a grid-like manner relative to one another,

wherein the gill structure with the gills includes a plurality of grid lines (RZ) and a plurality of grid columns (RS) wherein each respective grid line of the plurality of grid lines (RZ) extend in parallel to the flow direction (DR) and each respective grid column of the plurality of grid columns (RS) extend perpendicularly to the flow direction (DR),

wherein the individual gills each extend along an extension direction (ER) and each have a gill depth (KT) measured along the extension direction (ER),

wherein the individual gills of a respective grid line (RZ) are arranged with a predetermined fin density (RD) following one another perpendicularly to the flow direction (DR),

wherein the flow direction (DR) and the extension direction (ER) are arranged at an acute gill angle (β) relative to one another,

wherein the individual gills are arranged relative to one another so that the following gill relationship is substantially satisfied:

β=arctan((1/RD)/(2*KT))

2. The corrugated fin according to claim 1, wherein the plurality of individual gills are arranged relative to one another so that at least one first gill is arranged in a certain grid column and is arranged substantially in a virtual extension along the extension direction (ER) of a second gill that is arranged in a grid column next to but one relative to the defined grid column with the first gill.

3. The corrugated fin according to claim 1, wherein

the fin density (RD) is more than 110 Ri/dm.

4. The corrugated fin according to claim 1, wherein

the gill depth (KT) is at least 1.1 mm.

5. The corrugated fin of claim 1, wherein

a material thickness (D) of the fin sheet is between 0.05 mm and 0.1 mm.

6. The corrugated fin according to claim 1, wherein

a fin depth (RT) of the corrugated fin measured in the flow direction (DR) is between 15 mm and 80 mm.

7. A heat exchanger in particular for a motor vehicle, comprising

multiple first and second fluid paths alternately following one another along a stack direction (SR) which are fluidically separated from one another for being flowed through by a first and second fluid respectively,

wherein in at least one first fluid path, the corrugated fin of claim 1 is arranged.

8. The heat exchanger according to claim 7, wherein the at least one corrugated fin supports itself on two boundary elements located opposite one another in the stack direction (SR) and delimiting the first fluid path with the corrugated fin arranged therein.

9. A method for producing a corrugated fin according to claim 1,

providing a fin sheet of corrugated design that is configured to be flowed through along a flow direction (DR) by a first fluid, in particular a gas,

forming a gill structure having a plurality of longitudinally shaped gills (4) arranged grid-like relative to one another,

wherein the gills are arranged upon the fin sheet with a plurality of grid lines (RZ) and a plurality of grid columns (RS) so that the individual grid lines (RZ) extend parallel to the flow direction (DR) and the individual grid columns (RS) are disposed perpendicularly to the flow direction (DR), wherein the individual gills each extend along an extension direction (ER) and have a gill depth (KT) measured along the extension direction (ER),

wherein the individual gills of a respective grid line (RZ) are arranged with a predetermined fin density (RD) following one another perpendicularly to the flow direction (DR), so that the flow direction (DR) and the extension direction (ER) are arranged at an acute gill angle (β) relative to one another,

β=arctan((1/RD)/(2*KT)),

wherein KT is the gill depth and RD the gill density.

10. The method according to claim 9, wherein

an actually realised angle β* of at least one gill preferentially deviates by up to +/−3°, from the gill relationship β=arctan((1/RD)/(2*KT)).

11. The method according to claim 9, wherein

the individual gills of the plurality of gills are arranged and oriented relative to one another so that at least one first gill arranged in a certain grid line of the plurality of grid lines is substantially arranged in a virtual extension along the extension direction (ER) of a second gill which is arranged in a grid column adjacent to the certain grid column with the first gill.

12. The method according to claim 9, wherein

a fin density (RD) of more than 110 Ri/dm is provided.

13. The method according to claim 9, wherein

the gills are provided with a gill depth (KT) of at least 1.1 mm.

14. The corrugated fin according to claim 6, wherein, the fin depth of the corrugated fin measured in the flow direction is between 15 mm and 55 mm.

15. The heat exchanger of claim 7, wherein the corrugated fin is provided in multiple first fluid paths.

16. The heat exchanger of claim 7, wherein the corrugated fin is provided in all first fluid paths.

17. The method according to claim 10, wherein the actually realised angle β* of at least one gill deviates by up to +3°/−1° from the gill relationship β=arctan ((1/RD)/(2*KT)).