JP2019219139A - Corrugated fin for heat exchanger - Google Patents

Abstract

To prevent clogging in a circulation direction of air flow, and to enhance heat exchange by reducing air resistance, in a fin having fine wave-shaped irregularity on a rising surface and a falling sure of each wave of a corrugated fin, in a heat exchanger in which the corrugated fins and flat tubes are alternately arranged.SOLUTION: Irregular waves 2 are formed on a rising surface and a falling surface of each wave in a thickness direction of a metallic plate, an upstream flat face 3 free from the irregular wave 2 is formed on an upstream end portion of air current 1 of each wave, and a width t1 in a circulation direction of the air flow 1, of the upstream flat face 3 is 0.5 mm-2.5 mm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a corrugated fin used for a heat exchanger such as a radiator, an oil cooler, a charge air cooler, an EGR cooler, and the like.

  As an example, in a radiator used in construction machinery, flat tubes and corrugated fins are alternately arranged in parallel, and both ends of each flat tube are inserted into a pair of tanks. The heat medium for cooling the engine cooling water flows in the flat tube, and the airflow blown by the fan flows on the outer surface of the flat tube and the corrugated fin in the ridge direction of the corrugated fin. Then, heat exchange is performed between the heat medium and the airflow in the flat tube.

Patent Literature 1 below describes a corrugated fin and a heat exchanger including the same. This corrugated fin is formed by folding and bending a band-shaped metal plate into a wave form, and a corrugated wave whose cross section is uneven in the thickness direction of the metal plate is formed on the upper surface and the lower surface of each wave, and the air current flows in the ridgeline direction of each wave. Is led.
The uneven waves formed on the rising surface and the lower surface include those having a plane formed obliquely, those having an arc shape, and others.

JP 2011-112331 A

The fin described in Patent Document 1 also has an uneven wave on the end face in the airflow direction. Then, at the fin end on the upstream side of the airflow, the uneven shape increases the fluid resistance and causes clogging due to dust and the like included in the airflow.
At the end of the fin on the downstream side of the air flow, the temperature difference between the gas and the corrugated fin is reduced and the contribution to heat exchange is small. Pressure loss has occurred.
Accordingly, it is an object of the present invention to reduce the fluid resistance and to suppress clogging of fins at an inflow side end of an airflow.

The corrugated fin according to the first aspect of the present invention is a corrugated fin in which the strip-shaped metal plate is folded and bent into a waveform, and the air flow 1 is guided in the direction of the ridgeline 5 of each wave.
An uneven wave 2 is formed in the thickness direction of the metal plate on the rising surface and the lower surface of each wave, and an upstream flat surface 3 free of the uneven wave 2 is formed at the upstream end of the air current 1 of each wave. A corrugated fin for a heat exchanger, wherein the width t1 of the formed upstream flat surface 3 in the flow direction of the air flow 1 is 0.5 mm to 2.5 mm.

According to a second aspect of the present invention, there is provided a corrugated fin in which a strip-shaped metal plate is folded and bent into a waveform, and the airflow 1 is guided in a direction of a ridgeline 5 of each wave.
An uneven wave 2 is formed in the thickness direction of the metal plate on the upper and lower surfaces of each wave, and a downstream flat surface 4 free of the uneven wave 2 is formed at the downstream end of the airflow 1 of each wave. A corrugated fin for a heat exchanger, wherein the width t2 of the formed flat surface 4 in the flow direction of the air flow 1 is 0.9 mm to 4.6 mm.

According to the first aspect of the present invention, an upstream flat surface 3 having a width t1 of 0.5 mm to 2.5 mm, on which an uneven wave is not formed, is provided at an end of the corrugated fin on the upstream side in the airflow direction. Therefore, clogging of the corrugated fin is prevented. That is, the clogging of dust, which tends to concentrate on the upstream edge of the fin, is suppressed, and the flow of air is maintained.
Further, as is clear from the characteristic curve of FIG. 2, the exchange heat amount (fan matching heat radiation amount) increases as compared with the conventional fin point A having no flat surface. This is because the effect of the increase in the flow rate due to the decrease in the pressure loss of the flat surface is greater than the adverse effect of the decrease in the heat transfer area due to the upstream flat surface 3. This is because the amount of matching heat radiation increases.

  According to the second aspect of the present invention, a downstream flat surface 4 having a width t2 of 0.9 mm to 4.6 mm in which no corrugated wave is formed is provided at an end of the corrugated fin on the downstream side in the airflow direction. Therefore, as is clear from the characteristic curve shown in FIG. 4, the pressure loss was reduced more than the conventional fin point A having no flat surface due to the adverse effect such as the decrease in the heat transfer area due to the flat surface. As a result, the effect of the increase in the flow rate exceeds the effect, and the exchange heat amount (fan matching heat radiation amount) in consideration of the capacity of the cooling fan increases.

The front view (A) and the perspective view (B) of the corrugated fin 7 for heat exchangers of the 1st Example of this invention. A characteristic curve in which the width of the upstream flat surface 3 in the corrugated fin 7 for the heat exchanger is set on the horizontal axis, and the fan matching heat radiation amount ratio is set on the vertical axis. The front view of the corrugated fin 7 for heat exchangers of the 2nd Example of this invention. A characteristic curve in which the width of the downstream flat surface 4 in the corrugated fin 7 for the heat exchanger is set as the horizontal axis, and the fan matching heat radiation amount ratio is set as the vertical axis. The front view of the corrugated fin 7 for heat exchangers of the 3rd Example of this invention. The perspective view of the heat exchanger core which formed the corrugated fin 7 for heat exchangers of this invention, and the flat tube 6 in parallel. The front view (A) and the perspective view (B) of the corrugated fin 7 for heat exchangers of another Example of this invention. FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. 7. Modification 1 of the embodiment. Modification 2 of the embodiment. The perspective view of the heat exchanger core using the corrugated fin of the embodiment. The front view of a heat exchanger.

Next, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a corrugated fin 7 for a heat exchanger according to a first embodiment of the present invention. FIG. 1 (A) is a front view thereof, and FIG. 1 (B) is a schematic perspective view.
The corrugated fins for a heat exchanger are formed by, for example, folding and bending an aluminum band-shaped metal plate into a waveform, and the air flow 1 flows parallel to the ridgeline 5 of each wave.

  The corrugated fins 7 for the heat exchanger are formed with the corrugated waves 2 on the rising surface and the rising surface of each wave, respectively. The uneven wave 2 is formed in a waveform whose cross section is shallow in the thickness direction of the metal plate. Each of the concavities and convexities is inclined in one oblique direction in the front view of FIG. An upstream flat surface 3 is formed at the upstream end of the airflow 1 of the heat exchanger corrugated fin 7. The optimum width t1 of the upstream flat surface 3 in the flow direction of the airflow 1 is 1.5 mm. Note that the width t1 can be at least in a range L of 0.5 mm to 2.5 mm.

In such a heat exchanger corrugated fin 7, as shown in FIGS. 6 and 12, a flat tube 6 and a heat exchanger corrugated fin 7 are alternately arranged in parallel to form a core, and engine cooling water is supplied from one tank. On the other hand, the air flow 1 circulated through the flat tubes 6 through the tanks, and the air flow 1 generated by the fan flows to the outer surface side of the flat tubes 6 and the corrugated fins 7 for the heat exchanger. Then, heat exchange is performed between the air flow 1 and the fluid in the flat tube 6.
In this embodiment, the upstream flat surface 3 is formed only at the end of the airflow 1 in the inflow direction, and does not exist at the downstream end of the heat exchanger corrugated fin 7.

FIG. 2 is a characteristic curve in which the width t1 of the upstream flat surface 3 of the heat exchanger corrugated fin 7 is plotted on the horizontal axis, and the fan matching heat radiation amount ratio is plotted on the vertical axis.
On the vertical axis, point A is a fan matching heat radiation amount in the case of the conventional fin having no upstream flat surface 3, and shows a value in comparison with the conventional heat radiation amount with respect to a change in the width of the flat surface. . The following is clear from this characteristic curve. When the width t1 of the upstream flat surface 3 is 1.5 mm with respect to the heat exchanger corrugated fin 7 having no upstream flat surface 3, the characteristic curve has the maximum value (max). ), The amount of heat dissipation increased as compared with the conventional corrugated fin when the upstream flat surface 3 was at least in the range L of 0.5 mm to 2.5 mm.

  This is a result of the advantage of providing the upstream flat surface 3 exceeding the disadvantage of not providing it. That is, when the width t1 of the upstream flat surface 3 in the direction of the airflow 1 is in the range L of 0.5 mm to 2.5 mm, the heat exchange amount (fan matching heat radiation amount) increases as compared with the conventional fin having no upstream flat surface 3. I do. This is because the effect of the increase in the flow rate due to the decrease in the pressure loss due to the presence of the flat surface exceeds the adverse effect of the decrease in the heat transfer area due to the upstream flat surface 3. This is because the amount of matching heat radiation increases.

Next, FIGS. 3 and 4 show a second embodiment of the present invention. In this embodiment, a downstream flat surface 4 is provided at the downstream end of the air flow 1.
The width t2 of the downstream flat surface 4 in the flow direction of the airflow 1 is optimally 2 mm.
Note that the width t2 is at least in the range L of 0.9 mm to 4.6 mm and sufficiently exceeds the heat radiation amount in the case of the conventional fin point A where the downstream flat surface 4 does not exist.
The characteristic curves in FIGS. 2 and 4 indicate that the wind speed at which the airflow 1 flows into the heat exchanger core is 4 m / s (20 ° C.), the temperature of the engine cooling water flowing into the flat tube is 80 ° C. The corrugated fin has a fin height of 5.3 mm, a fin pitch of the corrugated fin of 2.5 mm, and corrugated fins having a corrugated fin having an uneven surface inclined in one direction obliquely to a plane on the upper and lower surfaces. Under the conditions that formed.

Next, FIG. 5 shows a third embodiment of the invention. This embodiment is different from the above embodiments in that an upstream flat surface 3 is provided at the upstream end of the airflow 1 and a downstream flat surface 4 is provided at the downstream end. Is provided.
By doing so, the embodiment of FIG. 5 has both the effect of FIG. 2 and the effect of FIG. That is, the upstream flat surface 3 prevents corrugated fins from being clogged, and the downstream flat surface 4 further increases the amount of exchanged heat (fan matching heat radiation) in consideration of the capacity of the cooling fan.

  7 to 11 show another embodiment of the present invention. FIG. 7A is a front view, FIG. 7B is a perspective view of the same, and FIG. 8 is a VIII-VIII arrow in FIG. 9 is a first modified example thereof, FIG. 10 is a second modified example thereof, and FIG. 11 is a perspective view of the core thereof. These drawings are different from the above-described embodiments in the planar shape of the corrugated waves 2 formed on the rising surface and the rising surface of each wave of the corrugated fin. In each of the above-described embodiments, the uneven wave 2 is formed to be inclined in one oblique direction, but in each of FIGS. 7 to 11, it is formed in a V-shape.

FIG. 7 shows the basic form thereof, having an upstream flat surface 3 at the upstream end of the airflow 1, and FIG. 9 shows a first modification thereof having a downstream flat surface 4 at the downstream end of the airflow 1. Reference numeral 10 denotes a second modified example, which has an upstream flat surface 3 and a downstream flat surface 4 at both ends in the flow direction of the air flow 1.
The present invention is not limited to the above embodiments, and the shape of the uneven wave 2 can be modified into various shapes.

  The corrugated fin of the present invention can be used for various heat exchangers such as radiators, oil coolers, charge air coolers, and EGR coolers.

DESCRIPTION OF SYMBOLS 1 Airflow 2 Concavo-convex wave 3 Upstream flat surface 4 Downstream flat surface 5 Ridge line 6 Flat tube 7 Corrugated fin for heat exchanger Point A Conventional fin L Range t1 width t2 width

Claims (2)

In a corrugated fin in which a band-shaped metal plate is folded and bent into a waveform, and an air current (1) is guided in a ridgeline direction of each wave,
An uneven wave (2) is formed in the thickness direction of the metal plate on the upper surface and the lower surface of each wave, and the uneven wave (2) is present at the upstream end of the air current (1) of each wave. An upstream flat surface (3) is formed, and a width (t1) of the upstream flat surface (3) in the flow direction of the airflow (1) is 0.5 mm to 2.5 mm. Corrugated fin. In a corrugated fin in which a band-shaped metal plate is folded and bent into a waveform, and an air current (1) is guided in a ridgeline direction of each wave,
An uneven wave (2) is formed in the thickness direction of the metal plate on the rising surface and the lower surface of each wave, and the uneven wave (2) is present at the downstream end of the airflow (1) of each wave. A downstream flat surface (4) that is not formed is formed, and a width (t2) of the downstream flat surface (4) in the flow direction of the airflow (1) is 0.9 mm to 4.6 mm. Corrugated fin.

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