EP4023988A1

EP4023988A1 - Heat exchanger

Info

Publication number: EP4023988A1
Application number: EP20461606.4A
Authority: EP
Inventors: Andrzej JUGOWICZ; Mateusz LIPOWSKI; Lukasz WIDZYK; Adam Bedek
Original assignee: Valeo Autosystemy Sp zoo
Current assignee: Valeo Autosystemy Sp zoo
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2022-07-06

Abstract

A heat exchanger for for heat exchange between a first fluid and a second fluid, is provided. The heat exchanger includes a first manifold, a second manifold, heat exchange tubes and a fin section. The heat exchange tubes is axially extending and providing a fluidal communication between the first manifold and the second manifold for the first fluid. The fin section is in contact with the heat exchange tubes for facilitating heat exchange between the first fluid and the second fluid. The fin section further includes a first louver section having a first louver length and a second louver section having a second louver length. The second louver section is arranged downstream with respect to the first louver section in the direction of the fluid intended to flow there through. Further, the second louver length is different from the first louver length.

Description

The present invention relates to a heat exchanger. In particular, this invention relates to heat exchanger fins having various sizes of louvers provided in a heat exchanger.
Conventionally, the heat exchanger may comprise two fluid circuits configured to exchange the heat. Further, one fluid circuit may be adapted for airflow, and other fluid circuit may be adapted for a coolant. Further, fins are provided in the airflow fluid circuit of the heat exchanger and in contact with heat exchange tubes to increase heat exchange between airflow and the coolant. The fins may increase pressure drop of airflow across the airflow fluid circuit, thereby, increasing heat exchange efficiency between the air flowing in the airflow fluid circuit and the coolant flowing in another fluid circuit. Further, the fins are provided with louvers to further increase heat exchange area across the airflow fluid circuit. The louvers may be formed in a form of small cuts defined on the fins. The louver may be bended along their length to increase air pressure drop across the airflow fluid circuit.
Further, the louvers formed in fins may be in same length, so the airflow pressure drop across the core of the heat exchanger is homogenous. However, there is a temperature difference between airflow in the inlet area of the airflow fluid circuit and the outlet area of the airflow fluid circuit. Therefore, the homogenous airflow pressure drop across the core may cause non-uniform heat exchange between the air and the coolant. For example, the air entering into the airflow fluid circuit may have higher temperature, in case the heat exchanger is charge air cooler, than the air flowing the outlet area of the airflow fluid circuit. In case the pressure drop across the core is homogenous, the heat exchange between the air and the coolant is higher at the inlet area of the airflow fluid circuit than of the outlet area of the airflow fluid circuit. As a result, the heat exchange tubes may undergo high stress due to temperature gradient between the inlet area and outlet area of the airflow fluid circuit, thereby causing cracks on the heat exchange tubes and reduce service life of the heat exchanger.
Accordingly, there remains a need for a heat exchanger provided non-uniform louver section in fins to achieve heterogeneous pressure drop across the core of the heat exchanger. Further, there remains another need for heterogeneous louver sections defined on the fins of the heat exchanger that creates heterogeneous pressure drop across the core of the heat exchanger, thereby optimizing thermal performance of the heat exchanger.
In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.
In view of forgoing, the present invention relates to a heat exchanger for heat exchange between a first fluid and a second fluid. In particular, the invention related to heat exchanger fins. The heat exchanger includes a first manifold, a second manifold, a plurality of heat exchange tubes and a fin section. The plurality of heat exchange tubes is axially extending and providing a fluidal communication between the first manifold and the second manifold for the first fluid. Further, the first fluid flows from the first manifold to the second manifold in the first fluid direction and the second fluid flows between the heat exchange tubes in the second fluid direction perpendicular to the first fluid direction. The fin section is in contact with the heat exchange tubes for facilitating heat exchange between the first fluid and the second fluid. The fin section further includes at least one first louver section having a first louver length and at least one second louver section having a second louver length. The second louver section is arranged downstream with respect to the first louver section in the direction of the fluid intended to flow there through. Further, the second louver length is different from the first louver length.
In one embodiment, the first louver length is bigger than the second louver length.
In another embodiment, the first louver length is smaller than the second louver length.
Further, the first louver section and the second louver section are formed as angled slats on the fin section.
Generally, the number of louvers in the first louver section is equal to the number of louvers in the second louver section.
Further, the first louver section and the second louver section include louver sets sloping alternately away and towards the fin section in the direction of the fluid intended to flow there-through.
In another aspect, the heat exchanger includes a plurality of first louver sections and a plurality of second louver sections arranged alternately on the fin section.
In one embodiment, the fin section is provided within at least one heat exchange tube. In such case, the heat exchanger is configured for operation as a water charge air cooler, the first fluid being air and the second fluid being a liquid coolant.
In another embodiment, the fin section is interlaced between adjacent heat exchange tubes. In such case, the heat exchanger is configured for operation as a radiator, the first fluid being a liquid coolant and the second fluid being air.
Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

Fig. 1 illustrates a perspective view of a heat exchanger, in accordance with an embodiment of the present invention;
Fig. 2 illustrates a schematic view of the heat exchanger of Fig. 1 without a housing, and showing heat exchange tubes;
Figs. 3 and 4 illustrate schematic views of a fin section arranged in the heat exchange tubes of Fig. 2, showing arrangement of the first louver section and the second louver section;
Fig. 5 illustrates a schematic view of a fin of the fin section of Fig. 2, in which the second louver section is arranged downstream to the first louver section on both lateral sides of the fin section; and
Fig. 6 illustrates a perspective view of the fin section of Fig. 2, in which the first louver section and the second louver section are alternatively arranged on both lateral sides of the fin section, in accordance with another embodiment of the present invention.

It must be noted that the figures disclose the invention in a detailed enough way to be implemented, said figures helping to better define the invention if needs be. The invention should however not be limited to the embodiment disclosed in the description.
The present invention envisages a heat exchanger provided with heterogeneous fin and louvers pattern to achieve uniform heat exchange between two fluid flowing there through. Conventional heat exchanger may include fin sections that are in contact to heat exchange tubes and homogenous size of louvers formed on the fin sections. As the louvers formed on the fin sections are of same length, airflow and pressure drop across the heat exchange tubes are uniform. As temperature of the airflow at an inlet area and an outlet area of the air flow circuit is different and pressure drop across the heat exchange tubes is uniform, heat exchange between two fluids flowing therein is non-uniform. Such non-uniform heat exchange between two fluids can leads to thermal shock on the heat exchange tubes. To overcome such problems, heterogeneous sizes of louvers are formed on the fin sections of a heat exchanger. The heat exchanger includes a plurality of heat exchange elements extended between a pair of manifolds, and a fin section in contact with the heat exchange elements. Further, a first fluid flow is defined in between the pair of manifolds, and a second fluid flow is defined in a direction perpendicular to the first fluid flow. In an aspect, the heat exchanger can be configured for operation as a water charge air cooler. In such case, the first fluid is air and second fluid is a liquid coolant. In another aspect, the heat exchanger can be configured for operation as a radiator. In such case, the first fluid is a liquid coolant and the second fluid is air.
Figs. 1 and 2 illustrate schematic views of a heat exchanger 100, in accordance with an embodiment of the present invention. In the present example, Fig. 1 is a perspective view of the heat exchanger 100, and Fig. 2 is a perspective view of the heat exchanger 100 without a housing 102. The heat exchanger 100 includes a first manifold 102A, a second manifold 102B spaced apart from the first manifold 102A and a plurality of heat exchange elements 104. Further, the plurality of heat exchange elements 104 can be heat exchange tubes. The plurality of heat exchange elements 104, hereinafter referred to as heat exchange tubes, are axially extending between the first manifold 102A and the second manifold 102B providing a fluidic communication between the first manifold 102A and the second manifold 102B. The heat exchanger 100 further includes a housing 102, in which the heat exchange tubes 104 are disposed. In other words, the heat exchange tubes 104 are at least partially encapsulated by the housing 102. Further, at least two fluid flows may be defined in the housing 102 and are in heat exchange configuration with each other, particularly, a first fluid flow and a second fluid fluidically isolated from the first fluid flow, but thermally coupled with the second fluid flow. Further, the first fluid flow defined in a first fluid circuit and the second fluid flow defined in a second fluid circuit.
In the present example, the first fluid flows from the first manifold 102A to the second manifold 102B through the heat exchange tubes 104 in the first fluid direction 106A. Further, the first fluid circuit is formed through the heat exchange tubes 104 in such a way the first fluid flows from the first manifold 102A to the second manifold 102B in the first fluid direction 106A. In other example, the first fluid circuit can be formed through the heat exchange tubes 104 in such a way the first fluid flows from the second manifold 102B to the first manifold 102A.The second fluid flows between the heat exchange tubes 104 in the second fluid direction 106B. The second fluid direction 106B is perpendicular to the first fluid direction 106A. Further, the housing 102 defines a path for the second fluid between the heat exchange tubes 104. Further, an inlet and outlet may be connected to housing 102 to introduce and receive the second fluid to/from the heat exchanger 100.
The heat exchanger 100 may further include a fin section 202 defined in contact with the heat exchange tubes 104. The fin section 202 having fins is provided in contact with the heat exchange tubes 104 in such a way that the fin section 202 facilitate heat exchange between the first fluid and the second fluid. The fin section 202 is provided in the heat exchanger 100 to increase pressure drop of the airflow flowing there through, so that the thermal performance of the heat exchanger 100 may increase. In case the heat exchanger 100 is adapted for an operation as charged air coolers, the fin section 202 is disposed within the heat exchange tubes 104. In such case, the first fluid is air and the second fluid a liquid coolant. In case the heat exchanger 100 is adapted for an operation as radiators, the fin section 202 can be interlaced between adjacent heat exchange tubes 104. In such case, the first fluid is a liquid coolant and the second fluid is air. The fin section 202 can be corrugated fins or flat fins. Further, the fin section 202 includes a first louver section and a second louver section. Further, the first louver section and second louver section are different in size. In one example, the fins in the first louver section having different length from the fins in the second louver section.
The length of each louver may be defined as the dimension between the leading and trailing edges. In other words, the louver length is measured relatively to the direction in which it elongates. The width of each louver may be defined as the dimension between the two ends wherein the louver is connected to the fin section. In other words, the width of the louver may be measured transversely with respect to the direction of elongation of the louver.
The first and second louver angles may be measured with respect to the intended first fluid flow direction, the first louver angle corresponding to the first louver section being located earlier within the fluid flow in which the fin section is intended to be located than the second angle corresponding to the second louver section being located later within the fluid flow in which the fin section is intended to be located.
Figs. 3, 4 and 5 illustrate different views of the fin section 202 of Fig. 2, in accordance with an embodiment of the present invention. In one embodiment, the fin section 202 includes at least one first louver section 204 having a first louver length "L1" and at least one second louver section 208 having a second louver length "L2". In another embodiment, the fin section 202 may include a plurality of first louver sections 204 and a plurality of second louver sections 208, in which the first louvers 202 and the second louver sections 208 are alternatively arranged thereon. In this example, Figs 3 and 4 are perspective views of the fin section 202 showing arrangement of the first louver section 204 and the second louver section 208. Fig. 5 illustrates a schematic view of a fin of the fin section 202 of Fig. 2, in which the second louver section 208 is arranged downstream to the first louver section 204 on both lateral sides of the fin section 202. In this embodiment, the fin section 202 is corrugated fins having lateral walls extending along the heat exchange tubes 104, and the lateral walls being a first wall 202A and a second wall 202B. The first louver section 204 and second louver section 208 are formed on both the first wall 202A and the second wall 202B of the fin section 202.
The second louver section 208 may be arranged downstream with respect to the first louver section 204 in the direction of the fluid intended to flow there through. In one example, the direction of the fluid intended to flow is the first fluid direction 106A. In other words, the direction of the fluid intended to flow can be the direction of the first fluid while flowing from the first manifold 102A to the second manifold 102B. In another example, the direction of the fluid intended to flow can be the direction of the first fluid while flowing from the second manifold 102B to the first manifold 102A. Further, the first louver length "L1" of the first louver section 204 is different from the second louver length "L2" of the second louver section 208. In one embodiment, the first louver length "L1" of the first louver section 204 is bigger from the second louver length "L2" of the second louver section 208. The first louver section 204 and the second louver section 208 may be adapted to increase pressure drop of the first fluid across the fin section 202. Further, the number of louvers in the first louver section 204 is equal to the number of louvers in the second louver section 208. In one embodiment, the number of louvers in the first louver section 204 is greater than the number of louvers in the second louver section 208. In yet another embodiment, the number of louvers in the first louver section 204 is smaller than the number of louvers in the second louver section 208.
Further, the first louver section 204 and the second louver section 208 are of different length, so the pressure drop across the fin section 202 is not homogenous. Particularly, the pressure drop at the first louver section 204 of the fin section 202 is greater than of the second louver section 208 of the fin section 202, in case the first louver length "L1" is bigger than of the second louver length "L2". Further, the temperature of the first fluid flowing in the first fluid circuit, corresponding to the first louver section 204 is greater than of the first flowing in the first fluid circuit, corresponding to the second louver section 208. As the temperature of the first fluid at the first louver section 204 is higher, the pressure drop of the first fluid has to be more to achieve effective heat exchange between the first fluid and the second fluid. As the first louver length "L1" in the first louver section 204 is bigger than the second louver length "L2", the pressure drop of the first fluid at the first louver section 204 is more than of at the second louver section 208, thereby obtaining in effective heat exchange between the first fluid and the second fluid. As a result, thermal shock at the inlet area of the heat exchange tubes 104, corresponding the first louver section 204 can be avoid, thereby risk of appearing cracks on the heat exchange tubes 104 is eliminated.
Further, the first fluid flowing in the first fluid circuit at the second louver section 208 is having lower temperature as compared to the first fluid flowing the first fluid circuit at the first louver section 204. Hence, the louvers in the second louver section 208 can be smaller as compared to the louvers in the first louver section 204 to achieve effective heat exchange between the first fluid and the second fluid in the first fluid circuit at the second louver section 208. So, the first louver length "L1" in the first louver section 204 is bigger than the second louver length "L2" in the second louver section 208. In another aspect, the first louver length "L1" in the first louver section 204 can be than the second louver length "L2" in the second louver section 208. In such case, temperature of the first fluid flowing in the first fluid circuit at the second louver section 208 is higher as compared to the temperature of the first fluid flowing in the first fluid circuit the first louver section 204.
In one embodiment, the first louver section 204 and the second louver section 208 are formed as angled slats on the fin section 202. Further, the first louver section 204 and the second louver section 208 are angled slats angled towards and away the fin section 202 in the direction of the fluid intended to flow there-through. In other words, the slats are angled towards and away the fin section 202 in the first fluid direction 106A. In another embodiment, the first louver section 204 and the second louver section 208 comprises louver sets 206A-B sloping alternatively away and towards the fin section 202 in the direction of the fluid intended to flow there through. Particularly, the louver set 206A in the first louver section 204 and the second louver section 208 is sloping away from the fin section 202 in the direction of the fluid intended to flow there through. Further, the louver set 206A in the first louver section 204 and the second louver section 208 is sloping towards the fin section 202 in the direction of the fluid intended to flow there through. In the fin section 202, the louver sets 206A-B in the first lateral wall 202A and the second lateral wall 202B are different. In the first lateral wall 202A of the fin section 202, the louver set 206B is downstream to the louver set 206A. In the second lateral wall 202B of the fin section 202, the louver set 206B is upstream to the lover set 206A.
Fig. 6 illustrates a perspective view of the fin section 202 of Fig. 2, in which the first louver section 204 and the second louver section 208 are alternatively arranged thereon, in accordance with another embodiment of the present invention. According to this embodiment, the first louver section 204 and the second louver section 208 are alternatively arranged on the both first and second lateral walls 202A-B of the fin section 202. Particularly, the first louver section 204 is alternately arranged with respect to the first louver section 208 in the direction of the fluid intended to flow there through. As explained above the louver set 206A-B alternately arranged on the first louver section 204 and the second louver section 208. The first louver section 204 may have the louver set 206A on the first lateral wall 202A of the fin section 202, and the louver set 206B on the second lateral wall 202B of the fin section 202. Similarly, the second louver section 202 may have the louver set 206B on the first lateral wall 202A of the fin section 202, and the louver set 206A on the second lateral wall 202B of the fin section 202.
As the first louver length "L1" in the first louver section 204 is bigger than the second louver length "L2", the pressure drop of the first fluid at the first louver section 204 is greater than of at the second louver section 208, thereby obtaining in effective heat exchange between the first fluid and the second fluid. As a result, thermal shock at the inlet area of the heat exchange tubes 104, corresponding the first louver section 204 can be avoided, thereby risk of appearing cracks on the heat exchange tubes 104 is reduced. As further result, heat exchange between the first and second fluids is uniform across the heat exchange tubes 104, thereby the thermal efficiency of the heat exchanger 100 is optimized.
In any case, the invention cannot and should not be limited to the embodiments specifically described in this document, as other embodiments might exist. The invention shall spread to any equivalent means and any technically operating combination of means.

Claims

A heat exchanger (100) for heat exchange between a first fluid and a second fluid, comprising:
a first manifold (102A) and a second manifold (102B);

a plurality of heat exchange tubes (104) axially extending and providing a fluidal communication between the first manifold (102A) and the second manifold (102B) for the first fluid, wherein the first fluid flows from the first manifold (102A) to the second manifold (102B) in the first fluid direction (106A) and the second fluid flows between the heat exchange tubes (104) in the second fluid direction (106B) perpendicular to the first fluid direction (106A); and

a fin section (202in contact with the heat exchange tubes (104) for facilitating heat exchange between the first fluid and the second fluid , characterized in that, the fin section (202) further comprises:
at least one first louver section (204) having a first louver length (L1); and

at least one second louver section (208) having a second louver length (L2), wherein the second louver section (208) is arranged downstream with respect to the first louver section (204) in the direction of the fluid intended to flow there-through, wherein the second louver length (L2) is different from the first louver length (L1).
The heat exchanger (100) as claimed in claim 1, wherein the first louver length (L1) is bigger than the second louver length (L2), wherein the louver length is measured relatively to the direction in which it elongates.
The heat exchanger (100) as claimed in claim 1, wherein the first louver length (L1) is smaller than the second louver length (L2), wherein the louver length is measured relatively to the direction in which it elongates.
The heat exchanger (100) as claimed in any of the preceding claims, wherein the first louver section (204) and the second louver section (208) are formed as angled slats on the fin section (202).
The heat exchanger (100) as claimed in any of the preceding claims, wherein the number of louvers in the first louver section (204) is equal to the number of louvers in the second louver section (208).
The heat exchanger (100) as claimed in any of the preceding claims, wherein the first louver section (204) and the second louver section (208) comprise louver sets sloping alternately away and towards the fin section (202) in the direction of the fluid intended to flow there-through.
The heat exchanger (100) as claimed in any of the preceding claims, wherein the heat exchanger (100) comprises a plurality of first louver sections (204) and a plurality of second louver sections (208) arranged alternately.
The heat exchanger (100) according to any preceding claim, wherein the fin section (202) is provided within at least one heat exchange tube (104).
The heat exchanger (100) according to claim 8, wherein the heat exchanger (100) is configured for operation as a water charge air cooler, the first fluid being air and the second fluid being a liquid coolant.
The heat exchanger (100) according to any of claims 1-7, wherein the fin section (202) is interlaced between adjacent heat exchange tubes (104).
The heat exchanger (100) according to claim 10, wherein the heat exchanger (100) is configured for operation as a radiator, the first fluid being a liquid coolant and the second fluid being air.