HEAT EXCHANGER ASSEMBLY HAVING SPLIT MINI-LOUVERED FINS
A heat exchanger assembly is provided having at least one header, a plurality of spaced apart fluid tubes in hydraulic communication with the header, and a plurality of corrugated fins disposed between the tubes. The corrugated fins include a planar portion having a louver segment defined between a pair of primary slits, in which the louver segment includes an intermediate slit splitting the louver segment into a pair of mini-louvers. The mini-louvers are counter-offset such that one of the mini-louvers is on one side of the planar portion and the other one of the mini-lover is on the other side of the planar portion. The mini-louvers may be pivoted about their respective junctures such that each of the mini-louver segments is oblique relative to the planar portion.
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This Application is a continuation-in-part of U.S. patent application Ser. No. 12/221,705, filed on Aug. 6, 2008, titled LOUVERED AIR CENTER FOR COMPACT HEAT EXCHANGER, the disclosure of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONThe invention relates to heat exchanger assemblies, particularly to heat exchangers having fins, and more particularly to air cooled heat exchangers having louvered fins.
BACKGROUND OF INVENTIONAir cooled heat exchanger assemblies for automobiles are used for transferring heat from various working fluids, such as an engine coolant, an engine lubricating oil, an air conditioning refrigerant, and a transmission oil. A typical air cooled heat exchanger assembly includes an inlet header, an outlet header spaced from the inlet header, a plurality of fluid tubes hydraulically connecting the inlet and outlet headers, and a plurality of corrugated fins disposed between adjacent fluid tubes. The core of the heat exchanger assembly is defined by the plurality of fluid tubes and the corrugated fins disposed between adjacent tubes. A stream of air is directed through the core of the heat exchanger assembly typically by a cooling fan or motion of the automobile. As the stream of air flows across the fins, heat in a fluid flowing through the fluid tubes is conducted through the walls of the tubes, into the fins, transferred to the stream of air flow.
Various types of fins and louver designs are known in the art with the object of increasing the heat transfer efficiency of the heat exchanger assembly. Examples of these designs include increasing the numbers of louvers on a planar portion of the fin, forming louvers at a predetermined angle relative to the planar portion of the fin, forming louvers above and below the planar portion of the fin, and disposing louvers at predetermined locations on the planar portion of the fin to alter the air flow pattern through the core to increase the heat transfer coefficient of air encountered by the fluid tubes and fins.
It is desirable to continuously improve fin and louver designs for a heat exchanger assembly to increase the heat transfer efficiency by maximizing the heat transfer coefficient of air encountered by the fluid tubes and fins while minimizing the pressure drop through the core.
SUMMARY OF THE INVENTIONIn concordance with the instant disclosure, a heat exchanger assembly is provided having at least one header, a plurality of spaced apart fluid tubes in hydraulic communication with the header, and a plurality of corrugated fins disposed between the tubes. The corrugated fins include a planar portion having a louver segment defined between a pair of primary slits, in which the louver segment includes an intermediate slit splitting the louver segment into a pair of mini-louvers. The mini-louvers are counter-offset such that one of the mini-louvers is on one side of the planar portion and other one of the mini-lover is on the other side of the planar portion. The mini-louvers may be pivoted about their respective junctures such that each of the mini-louvers is at an angle oblique relative to the planar portion.
The counter off-setting of the mini-louvers onto both sides of the planar portion allows the mini-louvers to extend a greater distance from the planar portion into the air-flow channel than what a single larger louver would allow. The greater louver penetration into the air flow channels increases the distance that the air flow has to travel and increases the number of boundary layer interruptions that the air flow has to encounter, thereby increasing heat transfer efficiency. The intermediate slit separating the first from the second mini-louver in each pair of mini-louvers defines an air flow passageway, which allows greater air flow efficiency and less air pressure drop for air flow through the core of the heat exchanger assembly.
Further features and advantages of the invention will appear more clearly on a reading of the following detailed description of an embodiment of the invention, which is given by way of non-limiting example only and with reference to the accompanying drawings.
This invention will be further described with reference to the accompanying drawings in which:
The following detailed description and appended drawings describe and illustrate various embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the inventions, and are not intended to limit the scope of the invention in any manner.
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In a normal operating state, a stream of ambient air is directed through the core 34 of the heat exchanger assembly 20 to transfer heat from a fluid flowing through the fluid tubes 28 to the ambient air. Heat is conducted through the walls of the tubes 28, into the fins, and transferred to the stream of air flow. It should be appreciated that heat may be transferred to the fluid flowing through the tubes 28 if the temperature of the stream of air is higher than the temperature of the fluid flowing through the tubes 28.
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The counter-offsetting of the first and second segments 168, 170 to define the first and second mini-louvers 176, 178 may be accomplished by mechanically displacing the material defining the secondary junctures 172 such that one of the first and second mini-louvers 176, 178 is on one side of the planar portion 154 and the other of the first and second mini-louvers 176, 178 is on the other side of the planar portion 154. Once off-set, the first and second mini-louvers 176, 178 may be individually pivoted about their respective secondary junctures 172 to a predetermined angle with respect to the planar portion 154. The predetermined degree of angle for the first and second mini-louvers 176, 178 may be the same or offset from each other.
As an alternative to mechanically displacing the material defining the secondary junctures 172 such that one of the first and second mini-louvers 176, 178 are on opposite side of the planar portion 154, the counter-offsetting of the first and second segments 168, 170 to define the first and second mini-louvers 176, 178 may be accomplished by pivoting the first and second segments 168, 170 in a second direction opposite that of the first pivot direction of the louver segment 162 such that one of the first and second mini-louvers 176, 178 is on one side of the planar portion 154 and the other of the first and second mini-louvers 176, 178 is on the other side of the planar portion 154. The pivoting of the first and second segments 168, 170 in a second direction opposite that of the first pivot direction may be varied according to the desired angle of the mini-louvers 176, 178 with respect to the planar portion 154.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims
1. A heat exchanger assembly comprising:
- at least one header;
- a plurality of fluid tubes in hydraulic communication with said header, wherein said tubes are spaced apart; and
- a plurality of corrugated fins disposed between and in thermal contact with said tubes, at least one of said corrugated fins comprises:
- a planar portion having a louver segment defined between a pair of primary slits,
- wherein said louver segment includes at least one intermediate slit between said pair of primary slits thereby splitting said louver segment into at least two mini-louvers.
2. The heat exchanger assembly of claim 1, wherein:
- said primary slits and said at least one intermediate slit are parallel,
- each of said primary slit includes a length L1,
- said at least one intermediate slit includes a length L2, and
- wherein said length L2 is less than said length L1, thereby defining a primary juncture transitioning said louver segment to said planar portion and defining a secondary juncture transitioning said mini-louvers to said primary juncture.
3. The heat exchanger assembly of claim 1, wherein said louver segment includes a primary juncture transitioning said louver segment to said planar portion, and said louver segment is pivoted about such primary juncture such that said louver segment is oblique relative to said planar portion.
4. The heat exchanger assembly of claim 3, wherein each of said mini-louvers includes a secondary juncture transitioning said mini-louvers to said primary juncture.
5. The heat exchanger assembly of claim 4, wherein said mini-louvers are counter-offset such that one of said mini-louvers is on one side of said planar portion and other one of said mini-lover is on the other side of said planar portion.
6. The heat exchanger assembly of claim 5, wherein each of said mini-louvers is pivoted about respective said secondary junctures such that each of said mini-louver segment is oblique relative to said planar portion.
7. The heat exchanger assembly of claim 6, wherein each of said mini-louvers includes a front edge and an opposite trailing edge, wherein said mini-louvers partially overlap one another such that the rear edge of one mini-louver extends past the front edge of the other said mini-louver.
8. The heat exchanger assembly of claim 7, wherein said planar portion includes a leading edge, and wherein said front edges of said mini-louvers are parallel with said leading edge of said planar portion.
9. The heat exchanger assembly of claim 5, wherein said intermediate slit defines an air passageway between said mini-louvers on either side of said planar portion.
10. A split mini-louver for a heat exchanger assembly, comprising:
- a planar portion having a louver segment defined between a pair of primary slits,
- wherein said louver segment includes at least one intermediate slit between said pair of primary slits, thereby splitting said louver segment into at least two mini-louvers.
11. The split mini-louver for a heat exchanger assembly of claim 10 wherein said mini-louvers are counter-offset such that one of said mini-louvers is on one side of said planar portion and other one of said mini-lover is on the other side of said planar portion.
12. The split mini-louver for a heat exchanger assembly of claim 11 wherein said intermediate slit defines an air passageway between said mini-louvers.
13. The split mini-louver for a heat exchanger assembly of claim 12 wherein each of said mini-louvers includes a front edge and an opposite trailing edge, wherein said mini-louvers partially overlap one another such that the rear edge of one mini-louver extends past the front edge of the other said mini-louver.
14. The split mini-louver for a heat exchanger assembly of claim 13 wherein each of said mini-louvers transitions into a secondary juncture.
15. The split mini-louver for a heat exchanger assembly of claim 13 wherein each of said secondary juncture transitions into primary juncture which transitions into said planar portion.
Type: Application
Filed: Mar 15, 2013
Publication Date: Aug 8, 2013
Applicant: DELPHI TECHNOLOGIES, INC. (TROY, MI)
Inventor: DELPHI TECHNOLOGIES, INC. (Troy, MI)
Application Number: 13/834,355
International Classification: F28F 1/12 (20060101);