JPH07198283A - Fin for heat exchanger - Google Patents

Abstract

PURPOSE:To realize high efficiency of a fin by allowing a high heat transfer rate and low pressure loss compatible. CONSTITUTION:A plurality of fin units 41-45, 51-55 bent in a wave plate state by alternately repeating crests 2 and intermediate wall parts 3 and having flat surfaces parallel with an air flow by louvering the intermediate wall parts or the intermediate wall parts themselves are continuously formed along an air flowing direction. A plurality of fin unit rows in which the fin units of the same position of the wall parts are aligned in a direction perpendicular to the flowing direction are formed in the flowing direction, and the adjacent fin unit rows are arranged in the state deviated at positions of the aligning direction to provide fins for a heat exchanger. A width (b) of the fin unit in the flowing direction is specified to 0.8-1.2m, and a positional deviation P0 of the adjacent rows is specified to 0.22-0.54m. It is desirable that the adjacent rows are deviated at the positions of the aligning direction at every other ones.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a capacitor,
In various heat exchangers for automobiles, residences, etc. that perform heat exchange with air such as an evaporator, a radiator, a heater core, and the like, regarding fins arranged in the air circulation gap, in particular, the wave is formed by alternately repeating the top part and the intermediate wall part. The present invention relates to a heat exchanger fin that is bent in a plate shape and is called a corrugated fin.

[0002]

2. Description of the Related Art In the fins as described above, a louver is provided in an intermediate wall portion of the fins in order to improve the heat transfer coefficient by causing a boundary layer dividing effect in the air passing through the fins. The so-called fin unit is formed by cutting and raising.

Conventionally, such a fin unit has generally been formed obliquely with respect to the air flow, but since the air passing through the fin is bent along the fin unit, the pressure loss becomes large. was there.

Therefore, an offset fin in which a plurality of fin units each having a surface parallel to the air flow are continuously formed along the air flow direction with the positions of the adjacent fin units displaced from each other in the thickness direction Fins are provided (for example, JP-A-62-56786,
JP-A-63-163785).

In such an offset fin, fin unit rows are formed in the direction orthogonal to the air flow direction by the fin units located at the same position on each intermediate wall portion, and adjacent fin unit rows are arranged in the alignment direction. Since the air is circulated across these fin unit rows, the fin units are arranged in a staggered position, so that the pressure loss of the air can be reduced while maintaining heat transfer performance higher than the fins in which the fin units are formed diagonally. Therefore, it is possible to provide a heat exchanger with high heat transfer efficiency.

However, even the above-mentioned conventional offset fin cannot sufficiently satisfy the recent demand for higher efficiency of the heat exchanger, and there is a strong desire to provide more efficient fins. .

The present invention has been made in view of the above technical background, and an object of the present invention is to provide a fin for a heat exchanger capable of realizing higher efficiency by achieving both high heat transfer coefficient and low pressure loss.

[0008]

In order to achieve the above object, the inventor has conducted experiments and studies as described later, and in an offset fin in which adjacent fin unit rows are displaced from each other, the fin unit air flow direction It was found that there is an optimum value for the width of the fin unit row and the amount of offset (offset amount) in the direction orthogonal to the air circulation direction of the fin unit row, and the present invention has been completed.

That is, the inventor first examined the influence of the width b of the fin unit in the air flow direction on the heat transfer coefficient. The fin (1) shown in FIG. 1 was used for the experiment. This fin will be described first.

In FIG. 1, (2) and (2) are upper and lower apex portions, and (3) is an intermediate wall portion (3) connecting between adjacent upper and lower apex portions (2) and (2). ) Are bent in a corrugated plate shape so as to be arranged in parallel at predetermined intervals.

Each intermediate wall portion (3) has an intermediate flat portion (31) in the air flow direction (width direction of the fin) indicated by an arrow W in FIG.
Is divided into a leeward side area (A) and a leeward side area (B), and each area has five fins over substantially the entire length (height) direction of the intermediate wall portion (3). Unit (41) ~
(45) and (51) to (55) are formed along the air circulation direction in a state where adjacent ones are displaced from each other in the thickness direction. Of these five fin units, two fin units on the air inflow side (41) (42)
(51) (52) and the two fin units (44) (45) (54) (55) on the air outflow side are the intermediate wall (3).
Is formed by cutting and raising a part of each of them in opposite directions, and the intermediate fin units (43) and (53) are formed by the intermediate wall portion (3) itself, and each has a surface parallel to the air flow. There is.

The fin units (41) to (4) as described above
5) and (51) to (55) are formed on each intermediate wall portion (3), the fin unit as a whole has fin units at the same position on each intermediate wall portion as shown in FIG. 1 (b). Are aligned in the direction perpendicular to the air flow direction, and the windward area (A)
And in the leeward side area (B), five fin unit rows (6
1) to (65) and (71) to (75) are formed. In addition, the adjacent fin unit rows have P0 to each other.
Of the fin unit rows (61) (71) of the first row and the fin rows of the fourth row in each of the windward and leeward areas (A) and (B). The unit rows (64) (74), the second fin unit row (6
2) (72) and the fifth fin unit row (65) (75)
And are in a matched state with no positional deviation.
That is, not only the adjacent fin unit rows, but also the positions of the fin unit rows adjacent to each other in the alignment direction are
It is out of position.

Using the fins shown in FIG. 1, the inventor first finds fin units (41) to (45) and (51) to (55).
The effect of the width b of the air flow direction on the heat transfer coefficient was investigated. FIG. 2 is a graph showing the results of numerically calculating the pressure loss and heat transfer coefficient when the value of b was changed. In FIG. 2, the horizontal axis b is the width of the fin unit in the air flow direction, and the vertical axis j / f is the value indicating the heat transfer efficiency, which is the dimensionless value j of heat transfer coefficient (Coburn's j factor) and the pressure loss. It is the ratio of the dimensionless value f (friction coefficient).

Here, the numerical calculation was performed by the following formula.

[0015]

[Equation 1]

As can be seen from the graph of FIG. 2, the heat transfer coefficient increases most when the width b of the fin unit in the air flow direction is in the range of 0.8 to 1.2 mm. Particularly preferable values of b are 1.
It is 0 to 1.1 mm.

Next, the inventor has found that the fin unit array (61)-
The influence of the positional shift amount P0 of (65) and (71) to (75) on the heat transfer coefficient was examined. FIG. 3 is a graph showing the results of numerically calculating pressure loss and heat transfer coefficient when the value of P0 was changed. In P0 / δ shown on the horizontal axis of FIG. 3, δ is the thickness of the boundary layer developed on the front and back sides of the fin unit by the air flow, that is, the thickness of the air trap layer with a small air flow, and is defined by the following equation.

[Equation 2]

As described above, the vertical axis j / f in FIG. 3 is a value indicating the heat transfer efficiency, which is a dimensionless value j of heat transfer coefficient (Colburn's j factor) and a dimensionless value f of pressure loss (friction). coefficient)
Is the ratio of

Numerical calculations of pressure loss and heat transfer coefficient were carried out by the following equations.

[Equation 3]

Regarding the average wind speed u between the fins in the above expression 3, the air conditioner heat exchanger is required to have a low front wind speed (air speed at the fin inlet) of 1 to 3 m / s. Therefore, u was set to 1 m / s and 3 m / s. Further, the fin units (41) to (45) and (51) to
The width b in the air flow direction of (55) was set to 0.8 mm and 1.2 mm, which are the minimum and maximum values of the optimum range, and the calculation of Equation 3 was performed.

As can be seen from the graph of FIG. 3, the horizontal axis P0
The efficiency is highest when / δ is 0.7 to 0.8.
Therefore, the fin unit rows (61) to (65) and (71) to
The heat transfer coefficient increases most when the positional deviation amount P0 of (75) is in the range of 0.22 to 0.54 mm. A particularly preferable value of P0 is 0.25 to 0.40 mm.

In order to qualitatively examine the influence of the positional deviation amount P0 on the behavior of the air flow, the streamline and temperature distribution of the air flow passing through the fin (1) were obtained by simulation. FIG. 5 shows the result. The same figure (a)
Uses the fin shown in FIG. 1, and P0 = 0.
It is set to 35 mm (within the range of the present invention). Further, as shown in FIG. 4B, the intermediate wall portion (3) is shown in FIG.
The fin units (41) to (45) and (51) to (5
5) A fin (1) having a protruding portion is used. Therefore, in the entire fin, as shown in FIG. 4B, fin unit rows (61) to (65) and (71) to (75) are formed by the fin units located at the same position of each intermediate wall portion (3). And the adjacent fin unit rows (61) (6
2), (62) (63) ... Are arranged in a state of being displaced from each other in the alignment direction by a displacement amount P0, but every other adjacent fin unit row (61) (6).
3), (62), (64) ... There is no misalignment between them and they are in an aligned state. And such fin (1)
In the above, P0 is set to 0.5 mm. The width b of the fin unit in the air flow direction is as shown in FIG.
(B) Both were set to 1.0 mm. In FIG. 4, parts having the same names as those of the fin shown in FIG. 1 are designated by the same reference numerals.

In the case of the embodiment of the present invention shown in FIG. 5 (a), the air flowing from the front is curved along the line connecting the vertices of the fin units (41) to (45) as indicated by the arrow. Fin unit rows (6
1) to (65) are divided into the gaps between the adjacent fin units. Therefore, the fin units (41) to (45), (5
As a result of not only the contact between the flat surface of 1) to (55) and the air but also the separated gap flow particularly contacts the windward and leeward edges of the fin unit, which promotes heat transfer in this portion. , The heat transfer rate increases. On the other hand, in the case of the comparative product of FIG. 5B, since the positional deviation amount P0 is large, the fin units (52) and (54) existing on the same line in the air flow direction are separated from the positional deviation amount P0, and The gap between the fin units (51) (53) (55) existing on the same line is
As shown by the arrow, the flow is meandering, but due to the wake of the fin units existing on the windward side, the fin units (52) and (54) or (51) and (53) or (adjacent to each other on the same line). The diversion into the gap between 53) and (55) is blocked. Therefore, it is considered that the contact of air to the windward and leeward end edges of the fin unit is suppressed, and the heat transfer effect is reduced accordingly. Reference numeral (8) shown in FIG. 5 is the above-mentioned boundary layer developed on the surface of each fin unit.

6 (a) and 6 (b) are respectively shown in FIG. 5 (a).
It is a graph which shows the heat transfer of the fin in (b).
The horizontal axis indicates the air flow direction, and the vertical axis indicates the Nusselt number Nu as an index indicating the heat transfer coefficient. Also from FIG.
In the comparative product of (b), the heat transfer coefficient at the windward edge of the fin unit is reduced, whereas in the product of the present invention of FIG. 5 (a), both the windward and leeward edges of the fin unit are provided. It can be seen that the effect of promoting heat transfer due to the interstitial flow is clearly observed in the part.

The present invention is premised on a so-called offset type corrugated fin, and fin units (41) to (41) to
The width (b) in the air flow direction of (45), (51) to (55) is regulated to 0.8 to 1.2 mm, and adjacent fin unit rows (61) to (65) and (71). ~
The positional deviation amount (P ₀ ) of (75) is 0.22 to 0.54.
The requirement is to be specified in mm, and other requirements are not limited at all. Therefore, the fin may have the structure shown in FIG. 1 or the structure shown in FIG. 4, but more preferably, as shown in FIG. 61) (62), (62) (63) ... Not only the fin unit rows (61) (6) that are adjacent to each other by more than one
3), (62) (64) ... It is preferable to use fins in a state where the positions in the alignment direction of them are also deviated. The reason for this is as follows.

That is, when the fins are inserted into the spaces between the heat exchange tubes during the assembly of the heat exchanger, the fins (1) are compressed in the longitudinal direction until the adjacent intermediate wall portions (3) come into contact with each other. There is a case where it is inserted in this state, and then pulled in the opposite direction, so that the desired arrangement state is corrected. Thus, like the fin shown in FIG. 4, every other adjacent fin unit row (6
1) (63), (62) (64) ... When the positions are the same, two fin units (41) (43) cut and raised on the same side in the thickness direction of the intermediate wall (3) ), (52)
Since the fin units (42) (53) of the adjacent intermediate wall portion (3) protrude in a complementary relationship between (54) ..., In the compressed state, as shown by the chain line in FIG. Two fin units (41) (43), (52) (54) on the wall
Between the fin units (4
2) (53) bites into it. For this reason, if the fins are simply pulled, both side edges of the bited fins will be caught by the side edges of the fins on both sides and will be difficult to separate. Interfere with. On the other hand, like the fin shown in FIG. 1, when every other adjacent fin unit rows are displaced in the alignment direction, even if the fins are compressed in the longitudinal direction, The fin units (42) (53), which are in a complementary positional relationship as shown by the chain line, do not bite between the two fin units (41) (43), (52) (54), and, therefore, Even when the fins are pulled, both side edges of the fins are not caught on the side edges of the fins on both sides, and the fin (1) can be smoothly assembled.

[0029]

Function Fin units (41) to (45), (51) to
The width (b) of the air flow direction of (55) is 0.8 to 1.2 m.
m adjacent to the fin unit row (6
1) Since the positional displacement amount (P ₀ ) of (62), (62) (63) ... Is regulated to 0.22 to 0.54 mm, the heat transfer efficiency is increased.

Of course, since the fin unit has a surface parallel to the air flow, it does not cause a large pressure loss as in the case where it is formed obliquely to the air flow.

Further, when the fin unit rows (61), (63), (62), (64), which are adjacent to each other, are misaligned in the alignment direction, the fins are compressed in the bending direction. , The two intermediate fins (41) (43), (52) (54), etc., of one intermediate wall (3) are adjacent to each other in the intermediate position. Fin unit (4
2) (53) does not bite, and the fin units do not engage with each other and cannot be separated even when pulled after compression.

[0032]

EXAMPLE A plate material made of No. 3000 series aluminum material having a thickness of 0.1 mm and a width of 16 mm was used to form adjacent fin unit rows (61) (62), (62) as shown in FIG.
(63) ... The offset corrugated fins are manufactured not only in the mutually adjacent fin unit rows (61), (63), (62), (64) but also in the offset position in the alignment direction. . Here, each fin unit (41)
To (45), (51) to (55), the length b in the air flow direction is 1.0 mm, and the adjacent fin unit rows (61) (6)
2), (62) (63) ... The positional displacement amount P0 is 0.33
Each of the values was set to mm to obtain a product of the present invention.

On the other hand, the same aluminum plate material as above is
As shown in FIG. 4, adjacent fin unit rows (61)
(62), (62) (63) ... The two fin unit rows (61) (6) are adjacent to each other although they are displaced from each other.
3), (62), (64) ... The offset corrugated fins were manufactured so that the positions of the two were matched. Here, each fin unit (41) to (45), (51) to (5
The length b in the air flow direction of 5) is set to 1.4 mm, and the positional deviation amount P0 of the adjacent fin unit rows (61) (62), (62) (63) ... It was an item.

Next, using the above two types of fins, as shown in FIG.
Assembled into a multi-flow type heat exchanger (condenser) shown in. In FIG. 9, (10) is an aluminum tube made of A1100 material, and a plurality of tubes (10) are arranged in parallel, and fins (1) are interposed between adjacent tubes. The core is formed by brazing the tube (10). Both ends of each tube are connected to a pair of left and right aluminum headers (11) and (12). In this heat exchanger, the refrigerant flowing from the refrigerant inlet pipe (13) into the left header (11) reaches the right header (12) while meandering through the refrigerant passage formed by the tube group, and the refrigerant outlet pipe ( It flows out from 14). Then, the refrigerant exchanges heat with the air passing through the fins while passing through the tube (10). Incidentally, (15) is a partition plate for partitioning the left and right headers, and (16) is a side plate arranged outside the outermost fin.

Using the above heat exchanger, the pressure loss of the air passing through the fin and the heat exchange rate of the heat exchanger when the air velocity at the fin inlet was changed to various values were examined. The results are shown in FIGS.

As is clear from the graphs shown in these figures, it can be confirmed that the product of the present invention can greatly increase the heat exchange efficiency despite the pressure loss being comparable to that of the comparative product. .

[0037]

As described above, according to the present invention, air is formed by corrugating a corrugated plate by alternately repeating the top portion and the intermediate wall portion, and by cutting and raising the intermediate wall portion or by the intermediate wall portion itself. A plurality of fin units having planes parallel to the flow are continuously formed along the air flow direction, and the fin units at the same position on each intermediate wall are aligned in the fin length direction to form a plurality of fins. In a fin for a heat exchanger in which unit rows are formed and adjacent fin unit rows are arranged with their positions in the alignment direction displaced from each other, the width b of each fin unit in the air flow direction is 0.8 to It is regulated to 1.2 mm, and the positional deviation amount P ₀ of the adjacent fin unit rows is 0.22 to 0.54 mm.
Therefore, it is possible to increase the heat transfer coefficient while keeping the pressure loss of the circulating air small. As a result, it is possible to provide a heat exchanger having excellent fin performance and, in turn, excellent heat exchange efficiency.

In the case where the fin unit rows that are adjacent to each other every other fin are displaced from each other in the alignment direction, even if a compressive force in the bending direction is applied to the fins, the fins of one intermediate wall part Between the two fin units, the fin unit of the adjacent intermediate wall portion in the complementary positional relationship does not bite, and there is no inconvenience that the fin units are engaged with each other even if they are pulled after compression. Therefore, the workability of assembling the heat exchanger,
The handleability of the fins can be improved.

[Brief description of drawings]

1A is a perspective view showing an example of a fin to which the present invention is applied, and FIG. 1B is a sectional view taken along line I-I of FIG.

FIG. 2 is a graph showing the relationship between the width of the fin unit in the air flow direction and the heat transfer coefficient.

FIG. 3 is a graph showing a relationship between a positional deviation amount of a fin unit row and a heat transfer coefficient.

FIG. 4 is a perspective view showing another example of fins to which the present invention is applied.

FIG. 5 is a streamline diagram of the air flow for the product of the present invention.

FIG. 6 is a streamline diagram of the air flow for the comparative product.

FIG. 7 is a cross-sectional view for explaining a state in which the fin shown in FIG. 4 is compressed in the length direction.

8 is a cross-sectional view for explaining a state when the fin shown in FIG. 1 is compressed in the length direction.

FIG. 9 (a) is a front view of a heat exchanger used in Examples,
(B) is a plan view.

FIG. 10 is a graph showing a relationship between air passage speed and pressure loss in the heat exchanger of FIG.

11 is a graph showing the relationship between the air passage speed and the heat exchange rate in the heat exchanger of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fin 2 ... Top part 3 ... Intermediate wall part 41-45, 51-55 ... Fin unit 61-65, 71-75 ... Fin unit row

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Yamamoto 6-224 Kaiyama-cho, Sakai City, Showa Aluminum Co., Ltd.

Claims (2)

[Claims] 1. A corrugated plate is formed by alternately repeating a top portion (2) and an intermediate wall portion (3), and by cutting and raising the intermediate wall portion (3) or by the intermediate wall portion itself. A plurality of fin units (41) to (45) and (51) to (55) having planes parallel to the air flow are continuously formed along the air circulation direction, and each of the intermediate wall portions (3). Fin units (41) to (4
5) and (51) to (55), fin unit rows (61) to (6) aligned in a direction orthogonal to the air flow direction.
5), (71) to (75) are formed in plural in the air flow direction, and are adjacent fin unit rows (61) (62),
(62) (63) ... In the heat exchanger fins arranged such that their positions in the alignment direction are displaced from each other, the fin units (41) to (45), (51) to
The width b of the air flow direction of (55) is regulated to 0.8 to 1.2 mm, and the adjacent fin unit rows (61)
The positional deviation amount P _{0 of} (62), (62), (63) ...
A fin for a heat exchanger, characterized in that the fin is regulated to 0.22 to 0.54 mm. 2. A fin unit row adjacent to every other fin unit row (6).
The heat exchanger fins according to claim 1, wherein the positions of (1), (63), (62), (64) ... Are misaligned.