JPH05340686A - Heat-exchanger - Google Patents

Abstract

PURPOSE:To improve performance of a heat-exchanger and to facilitate positioning of a fin by improving the coefficient of heat transfer of the second fluid side wherein fluid flows along the outside of a tube. CONSTITUTION:An inner protrusion 10 protruded internally of a tube 2 and an outer protrusion 11 protruding externally of the tube 2 are formed in a wall 2a being the flat part of the tube 2 forming a passage for engine cooling water. The inner and outer protrusions 10 and 11 are formed at the same interval as a fin pitch in the longitudinal direction of the tube 2 in a state that each of the inner and outer protrusions is arranged in one row.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for exchanging heat between a first fluid flowing inside a tube and a second fluid flowing outside the tube.

[0002]

2. Description of the Related Art Conventionally, in a refrigerant condenser or refrigerant evaporator of a refrigeration cycle for exchanging heat between refrigerant and air, or a heat exchanger such as a heater core or radiator for exchanging heat between engine cooling water and air, As a means for increasing the heat exchange efficiency, fins are provided in contact with the outer wall of the tube, which is a passage for the refrigerant and engine cooling water.

[0003]

However, since the air flowing outside the tube flows in a laminar flow state along the outer wall surface of the tube, the air flowing near the outer wall surface of the tube is separated from the outer wall surface of the tube. The temperature difference between the flowing air and the fluid flowing in the tube is different, and a temperature boundary layer is generated on the air side. Therefore, the air flowing near the outer wall surface of the tube has a problem that the temperature difference between the air flowing farther from the outer wall surface of the tube and the fluid flowing in the tube becomes less, and the total heat transfer amount becomes lower. The present invention has been made based on the above circumstances, and an object thereof is to provide a heat exchanger capable of increasing the heat transfer coefficient on the side of the second fluid flowing outside the tube.

[0004]

In order to achieve the above object, the present invention is provided with a tube through which a first fluid flows and an outer wall surface of the tube, the first fluid and the tube being provided in contact with the tube. A heat exchanger provided with fins for increasing heat exchange efficiency with a second fluid flowing outside of the tube, a plurality of which disturbs a flow of the second fluid flowing along the outer wall surface of the tube. The technical means is to appropriately provide the protrusions.

[0005]

In the heat exchanger of the present invention having the above structure, the projection of the outer wall surface of the tube appropriately disturbs the flow of the second fluid flowing along the outer wall surface of the tube. For this reason, the second fluid flowing outside the tube does not flow in a laminar flow state, and is disturbed by the projections to be in a turbulent state, so that the temperature distribution on the air side is made uniform.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which the heat exchanger of the present invention is applied to a heater core will be described with reference to FIGS. FIG. 1 is a perspective view of a tube, and FIG. 4 is a perspective view of a heater core.
In the heater core 1 of the present embodiment, the air (the second fluid of the present invention) blown into the vehicle compartment is cooled by the engine cooling water (the first fluid of the present invention).
It is heated by heat exchange with the fluid, and as shown in FIG. 4, a core portion 4 formed by alternately stacking tubes 2 and corrugated fins 3 that form passages for engine cooling water, an inlet tank 5, an outlet tank. 6 and a lower tank 7. The core portion 4 is arranged such that both ends of each tube 2 are in the vertical direction (vertical direction). The tube 2 is composed of a flat aluminum tube (or brass). The corrugated fin 3 (hereinafter abbreviated as fin 3) is a thin aluminum plate formed in a wavy shape.
The bent portion is brazed to the outer wall surface of the tube 2. The inlet tank 5 and the outlet tank 6 are provided on the upper portion of the core portion 4, and are connected to the respective tubes 2 in the right half and the left half in the stacking direction. Also, the inlet tank 5
Is provided with an inlet pipe 8 which is an inlet of engine cooling water, and the outlet tank 6 is provided with an outlet pipe 9 which is an outlet of engine cooling water. The lower tank 7
It is provided below the core portion 4 and communicates with each tube 2. The high-temperature engine cooling water flowing from the inlet pipe 8 into the inlet tank 5 flows downwardly through the tubes 2 communicating with the inlet tank 5 into the lower tank 7, and the tubes communicating with the outlet tank 6 from the lower tank 7. 2 flows upward and flows into the outlet tank 6. The engine cooling water flowing through each tube 2 is cooled by being blown by a cooling fan (not shown), and flows out from the outlet tank 6 through the outlet pipe 9.

In this embodiment, a plurality of inner projections 10 projecting inward of the tube 2 and a plurality of outer projections 11 projecting outside of the tube 2 (projections of the present invention) are formed on a wall 2a forming a flat portion of the tube 2. ) And are provided. Inner protrusion 1
As shown in FIG. 1, the 0s and the outer protrusions 11 are lined up one by one, and are provided in the longitudinal direction of the tube 2 at the same intervals as the fin pitch. That is, in the same cross section in the longitudinal direction of the tube 2, as shown in FIG. 2, two inner protrusions 10 and two outer protrusions 11 are provided at positions facing each other on both sides of the wall 2a forming the flat portion of the tube 2, respectively. Four protrusions are provided. It should be noted that the inner wall surface and the outer wall surface of the tube 2 have a recess 10 a and a recess 11 a that accompany the formation of the outer protrusion 11 and the inner protrusion 10. The outer protrusion 11 preferably has a height of 0.2 mm or more in order to position the fin 3. Further, the projection shape of the inner projection 10 and the outer projection 11 may be a hemispherical shape, an oval shape, or the like, but there is no particular limitation.

Here, the inner protrusion 10 and the outer protrusion 11
The effect of the provision of will be described. The fluid flowing along the wall surface of the tube 2 (engine cooling water inside the tube 2, air outside the tube 2) has a small temperature difference with the fluid flowing inside the tube near the wall surface of the tube 2, Since the temperature difference increases as the distance from the wall surface of the tube 2 increases, the temperature distribution shown in FIG. 3 is obtained. Therefore, by providing a projection on the wall 2a of the tube 2, the flow of the fluid flowing along the wall surface of the tube 2 is disturbed, and the fluid flowing near the wall surface of the tube 2 and the fluid flowing away from the wall surface of the tube 2 are disturbed. The replacement makes the temperature uniform, and as a result, the heat transfer coefficient can be increased.

Therefore, in the heater core 1 of the present embodiment, the temperature distribution of the engine cooling water flowing in the tube 2 can be made uniform by projecting the inner projection 10 inward of the tube 2, and the tube 2 can be made uniform. By projecting the outer protrusions 11 to the outside, the temperature distribution of the air flowing outside the tube 2 can be made uniform. As a result, the performance of the heater core 1 can be improved by improving the heat transfer coefficient on both the engine cooling water side and the air side. Further, by providing the outer protrusion 11 on the wall 2a forming the flat portion of the tube 2, the fins 3 bonded to the outer wall surface of the tube 2 can be positioned. It is possible to prevent the bonded portion (bent portion) of the fin 3 from being positioned in the recess 10a portion formed on the outer wall surface, and prevent the fin efficiency from being lowered due to the non-bonding of the fin 3.

[Modification] In the present embodiment, the inner protrusion 10 and the outer protrusion 11 are provided in the same cross section in the longitudinal direction of the tube 2, but FIG. 5 (a sectional view showing the longitudinal direction of the tube 2).
As shown in FIG. 5, the tube 2 may be provided with a shift of half a pitch in the longitudinal direction. Further, although the outer protrusions 11 are provided in the longitudinal direction of the tube 2 at the same intervals as the fin pitch, they may be set at intervals of an integral multiple of the fin pitch or at regular intervals other than this. Although the example in which the heat exchanger of the present invention is applied to the heater core 1 is shown, the heat exchanger of the present invention can also be applied to a radiator that is a radiator of engine cooling water, a refrigerant condenser and a refrigerant evaporator of a refrigeration cycle, and the like.

[0011]

The heat exchanger of the present invention disturbs the flow of the second fluid flowing outside the tube to make the temperature distribution on the second fluid side uniform, so that the second fluid and the tube flow. By increasing the heat transfer coefficient with the first fluid, the performance of the heat exchanger can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a tube of a heater core according to an embodiment.

FIG. 2 is a cross-sectional view of a tube according to this embodiment.

FIG. 3 is a diagram illustrating the flow of fluid when a projection is provided on the wall of the tube.

FIG. 4 is a perspective view of a heater core according to this embodiment.

FIG. 5 is a cross-sectional view of a tube showing a modified example of this embodiment.

[Explanation of symbols]

 1 Heater core (heat exchanger) 2 Tube 3 Corrugated fin 11 Outside protrusion (projection)

Claims (1)

[Claims] 1. A tube in which a first fluid flows inside, and a tube which is provided in contact with an outer wall surface of the tube to enhance heat exchange efficiency between the first fluid and a second fluid flowing outside the tube. A heat exchanger having fins, wherein the outer wall surface of the tube is appropriately provided with a plurality of protrusions for disturbing the flow of the second fluid flowing along the outer wall surface.