Heat exchanger

a technology of heat exchanger and refrigerant, which is applied in the direction of lighting and heating apparatus, tubular elements, and stationary conduit assemblies, etc., can solve the problems of excessive reduction of reduce the resistance to flow of refrigerant, and suppress the effect of heat exchange efficiency reduction

Inactive Publication Date: 2007-10-04
DENSO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0007]The present invention is made in view of the foregoing matter, and it is an object of the present invention to provide a heat exchanger having tubes with projections for disturbing flows of an internal fluid and an external fluid, which is capable of sufficiently maintaining or improving efficiency of heat exchange.
[0009]As the tube outer dimension increases, a passage area of a refrigerant passage increases and resistance to flow of the refrigerant reduces. Therefore, pressure loss of the refrigerant is reduced and hence the decrease of efficiency of heat exchange may be suppressed. However, if the tube outer dimension is increased more than necessarily, the resistance to flow of the refrigerant is reduced excessively. In this case, although the refrigerant flows smoothly, disturbing effect of the refrigerant is reduced.
[0010]Accordingly, the tube outer dimension is set in a range between equal to or greater than 0.8 mm and equal to or less than 1.9 mm. When the tube outer dimension is in this range, the pressure loss of the refrigerant is reduced while the disturbing effect of the refrigerant is maintained. Therefore, the efficiency of heat exchange is sufficiently provided.

Problems solved by technology

However, if the tube outer dimension is increased more than necessarily, the resistance to flow of the refrigerant is reduced excessively.

Method used

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first embodiment

[0029]A first embodiment will be described with reference to FIGS. 1 to 7. As shown in FIG. 1, a heat exchanger 10 is for example used as a refrigerant condenser of a refrigerating cycle for a vehicle air conditioner, and is mounted in an engine compartment of a vehicle at a position where outside air is sufficiently supplied when the vehicle is running.

[0030]The heat exchanger 10 has a generally rectangular outline and includes a heat exchanging part 13 and tanks 14, 15. The heat exchanging part 13 includes flat tubes and fins 12. The flat tubes 11 define refrigerant passages therein through which a refrigerant flows. The fins 12 are for example corrugated fins. The heat exchanging part 13 performs heat exchange between the refrigerant and air flowing outside of the flat tubes 11.

[0031]The tanks 14, 15 are coupled to opposite longitudinal ends of the tubes 11. The refrigerant is distributed into the flat tubes 11 from one of the tanks 14, 15 (e.g., a left tank in FIG. 1) and is col...

second embodiment

[0087]A second embodiment will be described with reference to FIG. 8. As shown in FIG. 8, the fins 12 do not have the louvers 12e, 12f on the flat walls 12c, 12d. Structures of the heat exchanger 10 other than the louvers 12e, 12f are similar to those of the heat exchanger 10 of the first embodiment.

[0088]In the heat exchanger 10 of the second embodiment, because the efficiency of heat radiation of the fins 12 slightly reduces due to elimination of the louvers 12e, 12f, the efficiency Q slightly reduces as compared with the efficiency Q of the first embodiment. However, the tubes. 11 have the similar structure as the first embodiment. Therefore, effects substantially similar to the effects of the first embodiment are provided in the second embodiment.

[0089]Accordingly, the relationships between the efficiency Q and the tube height H, projection pitch P and fin height F have the similar trends as those of the first embodiment, though the efficiency Q is slightly reduced in this embod...

third embodiment

[0090]A third embodiment will be described with reference to FIG. 9. In the third embodiment, the heat exchanger 10 has the similar structure as that of the second embodiment other than corners 22a, 23a of the projections 22, 23.

[0091]In the second embodiment, the corners 22a, 23a are chamfered into the arc shape. In the third embodiment, on the other hand, the corners 22a, 23a are not chamfered. Instead, the side walls of the projections 22, 23 and the outer surfaces of the tube main walls 20, 21 form edged corners, as shown in FIG. 9.

[0092]Also in this case, the effects similar to the second embodiment are provided. Therefore, the relationships between the efficiency Q and the tube height H, projection pitch P and fin height F have the similar trends as those of the second embodiment.

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Abstract

A heat exchanger has tubes defining refrigerant passages therein and fins disposed between the tubes. The tubes have tube main walls opposed to each other. The fins are joined to the tube main walls. The tube main walls have projections that project inside of the tubes and define recesses on outer sides of the tubes. Each of the tubes has an outer dimension, in a direction perpendicular to the tube main walls, in a range between equal to or greater than 0.8 mm and equal to or less than 1.9 mm.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is based on Japanese Patent Application No. 2006-103093 filed on Apr. 4, 2006, the disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to a heat exchanger, which is for example used as a refrigerant radiator for cooling a refrigerant flowing in tubes.BACKGROUND OF THE INVENTION[0003]U.S. Pat. No. 6,595,273 B2 (JP-A-2004-3787) discloses a heat exchanger having flat tubes, as a refrigerant radiator. The flat tubes have recesses on flat walls (tube main walls) thereof for allowing air to flow, thereby to improve the efficiency of heat exchange. The recesses are defined by projections formed on the tube main walls.[0004]The projections have serpentine side walls such that air flows in the recesses in a serpentine or meandering manner. Because the flow of air adjacent to outer surfaces of the tube main walls is disturbed, development of a temperature boundary layer a...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F28D1/02
CPCF28D1/05366F28F3/042F28F1/426F28F1/42
Inventor SHIMOYA, MASAHIROITOH, AKIRA
Owner DENSO CORP
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