JP2010223578A - Heat exchanger fin, and heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve close contact between a fin collar and heat transfer tube, in a cross-fin tube type heat exchanger. <P>SOLUTION: The fin collar (12) is constituted of a fin collar root part (121) that is a connection portion to a fin body (11), a fin collar intermediate part (122) and a fin collar re-flared part (123), and a cross-sectional shape of the fin collar (12) is a spline curve. Any one is selected, as a control point of the spline curve, out of an intermediate point (X1) of the fin collar intermediate part (122), the first end part (X2) of the fin collar intermediate part (122), and the second end part (X3) of the fin collar intermediate part (122). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to heat exchanger fins and heat exchangers, and more particularly to a cross fin tube heat exchanger fin and a cross fin tube heat exchanger.

  One type of heat exchanger for an air conditioner is a cross-fin tube heat exchanger. As shown in FIG. 12, in a conventional cross fin tube heat exchanger, an L-shaped fin collar 12 ′ having a straight cross-sectional shape is used, and a straight portion of the L-shaped fin collar 12 ′ and a heat transfer tube 2 ′. Some of them are intended to be in close contact with the outer peripheral surface. However, in the tube expansion process, a dent is generated at the intermediate portion of the straight portion of the fin collar, and a portion where the fin collar 12 'and the outer peripheral surface of the heat transfer tube 2' do not come into contact is generated. In this case, as shown in FIG. 13A, the contact gap between the fin collar and the outer peripheral surface of the heat transfer tube is large in the intermediate portion of the linear portion of the fin collar, and the contact area between the fin collar and the heat transfer tube is reduced. Heat transfer area is reduced. Further, as shown in FIG. 13 (b), stress concentration may occur at the contact portion between the fin collar and the heat transfer tube, and the fin collar may crack and the contact heat transfer rate may be reduced. Further, since the stress distribution of the linear portion of the collar is easily shifted in the left-right direction, a bending moment is generated, the fin collar is buckled, and a gap is generated between the heat transfer tube. Therefore, when the L-shaped fin collar having a straight cross-sectional shape is employed, there is a problem that a predetermined heat exchange amount cannot be obtained.

  In order to avoid the occurrence of a contact gap between the fin collar and the outer peripheral surface of the heat transfer tube, the heat exchanger fin 21 shown in FIG. 14 has three bends R (3) at three portions (22, 23, 24) of the fin collar, respectively. R1, R2, R3) are attached, and the respective bends R are smoothly contacted so that the fin collar shape is convex toward the heat transfer tube as a whole so that there is no straight portion (Patent Document 1). Compared with the L-shaped fin collar having a straight cross-sectional shape, the fin 21 having such a shape has improved adhesion between the fin collar and the heat transfer tube and improved heat exchange efficiency.

  The object of the present invention is to overcome the problems of the background art described above, provide a fin that minimizes the gap between the fin collar and the heat transfer tube after the expansion, and improve the adhesion between the fin collar and the heat transfer tube. That is. Moreover, it is improving the heat exchange efficiency of a heat exchanger.

  A fin for a heat exchanger according to a first aspect of the present invention includes a plate-like fin main body and an annular fin collar that extends in a direction intersecting the fin main body and has a through hole formed therein. Here, the fin collar is configured by a fin collar root portion, which is a connecting portion with the fin main body portion, a fin collar intermediate portion, and a fin collar reflare portion. In addition, the cross-sectional shape of the fin collar is the control point of the spline curve at the position of the intermediate point of the fin collar intermediate part, the intermediate point of the fin collar intermediate part, the first end of the fin collar intermediate part, and the first position of the fin collar intermediate part. It is a spline curve that passes through two end portions, a predetermined point of the fin collar refracted portion, and a predetermined point of the fin collar root portion.

  The spline curve can be controlled by a control point and the shape can be locally controlled. By making the cross-sectional shape of the fin collar into a spline curve, the fin color curve shape can be controlled by using some coordinates as control points so that the gap between the fin collar and the heat transfer tube after the expansion is minimized. In addition, since the gap between the fin collar and the heat transfer tube after the expansion is minimized, the adhesion between the fin and the heat transfer tube is improved.

  A heat exchanger fin according to a second aspect of the present invention is the heat exchanger fin according to the first aspect of the present invention, wherein the fin collar is composed of a fin collar root portion, a fin collar intermediate portion, and a fin collar reflare portion. . Further, the cross-sectional shape of the fin collar is formed by continuously connecting a plurality of spline curves including a first spline curve, a second spline curve, and a third spline curve. Here, the first spline curve is a spline curve that passes through the three points of the intermediate point of the fin collar intermediate portion, the first end portion of the fin collar intermediate portion, and the second end portion of the fin collar intermediate portion. The second spline curve is a spline curve that passes through a predetermined point of the fin collar flared portion and a first end portion of the fin collar intermediate portion on the fin collar flared portion side. The third spline curve is a spline curve that passes through a predetermined point of the fin collar root portion and a second end portion of the fin collar intermediate portion on the fin collar root portion side.

  Here, the cross-sectional shape of the fin collar is a shape that continuously connects the first spline curve passing through the three points, the second spline curve passing through the two points, and the third spline curve. By adopting such a shape, the contact gap between the fin collar and the outer peripheral surface of the heat transfer tube can be further reduced, and stress concentration that tends to occur at the contact portion between the fin collar and the heat transfer tube can be suppressed. it can. Further, X2 and X3 are independent variables, and since the number of spline curves is large, it is possible to create a fin color having an asymmetric shape with respect to the intermediate point X1 of the fin color, and the degree of freedom in layout is increased.

そのうち、０＜Ｎ１＜１、０＜Ｎ２＜１、Ｃ１、Ｃ２は所定値である。 The heat exchanger fin according to the third invention is the heat exchanger fin according to the second invention, wherein the plurality of spline curves are non-uniform rational B-splines. In addition, the relationship between the coordinates of the intermediate point (X1) of the fin collar intermediate part, the first end part (X2) of the fin collar intermediate part, and the second end part (X3) of the fin collar intermediate part is

Among them, 0 <N1 <1, 0 <N2 <1, C1, and C2 are predetermined values.

  Here, since the non-uniform rational B-spline curve is adopted, the range that can be controlled by the control point can be adjusted, and the influence of the control point on the curve can be manipulated. Here, the three control points including the intermediate point of the fin collar intermediate part and both ends of the fin collar intermediate part are controlled by the diameter of the heat transfer tube, the pitch in the stacking direction of the fins, the material of the heat transfer tube and the fin, The shape of the fin collar can be optimized so that the contact gap between the collar intermediate portion and the outer peripheral surface of the heat transfer tube is minimized. Further, X2 and X3 are independent variables, and since the number of spline curves is large, it is possible to create a fin color having an asymmetric shape with respect to the intermediate point X1 of the fin color, and the degree of freedom in layout is increased.

  The heat exchanger according to the present invention is a cross fin tube heat exchanger provided with a plurality of fins and a plurality of heat transfer tubes. Each fin has a fin main body having a plurality of through holes and a fin collar formed on the periphery of the through holes. Each heat transfer tube is inserted into the through-hole, and is in close contact with the fin collars of the plurality of fins by expansion. Further, the cross-sectional shape of the fin collar is a spline shape.

  Here, by adopting a fin collar whose cross section has a spline shape, the gap between the fin collar and the heat transfer tube after the expansion is controlled to the minimum, and the adhesion between the fin and the heat transfer tube can be improved.

  The cross-sectional shape of the fin collar is a shape that continuously connects the first spline curve passing through three points, the second spline curve passing through two points, and the third spline curve. By adopting such a shape, the contact gap between the fin collar intermediate portion and the outer peripheral surface of the heat transfer tube can be further reduced, and stress concentration that tends to occur at the contact portion between the fin collar and the heat transfer tube is suppressed. be able to.

  Furthermore, a non-uniform rational B-spline curve is adopted as the cross-sectional shape of the fin collar, and the three control points including the intermediate point of the fin collar intermediate part and both ends of the fin collar intermediate part are controlled, The shape of the fin collar can be optimized so that the contact gap with the outer peripheral surface of the heat transfer tube is minimized.

  As a result, the heat exchange efficiency of the cross fin tube heat exchanger can be improved.

  In the case of a fin collar having three or more bends R disclosed in Patent Document 1, the contact heat transfer coefficient is improved as compared with an L-shaped fin collar having a straight cross-sectional shape. No method is disclosed. In addition, there is a problem with the calculation formula for the contact heat transfer coefficient, and a predetermined contact heat transfer coefficient value cannot be obtained.

  The cross-sectional shape of the fin collar according to the present invention is such that the position of the intermediate point of the fin collar intermediate part is the control point of the spline curve, the intermediate point of the fin collar intermediate part, the first end of the fin collar intermediate part, and the fin collar intermediate part Is a spline curve that passes through the five points of the second end, a predetermined point of the fin collar reflare portion, and a predetermined point of the fin collar root portion.

  Here, the fin collar curve shape is controlled using several coordinates as control points so that the gap between the fin collar and the heat transfer tube after expansion is minimized by making the cross-sectional shape of the fin collar into a spline curve. Can do. In addition, the gap between the fin collar and the heat transfer tube after the expansion can be minimized, and the maximum contact pressure can be increased. As a result, the adhesion between the fin and the heat transfer tube is improved, and the contact heat transfer coefficient between the fin collar and the heat transfer tube after the expansion is improved.

  The cross-sectional shape of the fin collar according to the present invention is a shape that continuously connects the first spline curve passing through the three points, the second spline curve passing through the two points, and the third spline curve. By adopting such a shape, the contact gap between the fin collar and the outer peripheral surface of the heat transfer tube can be further reduced. In addition, the contact pressure can be increased, and stress concentration that easily occurs at the contact portion between the fin collar and the heat transfer tube can be suppressed. As a result, the adhesion between the fin and the heat transfer tube is improved, and the contact heat transfer coefficient between the fin collar and the heat transfer tube after the expansion is improved. Furthermore, since X2 and X3 are independent variables and the number of spline curves is large, it is possible to create a fin color having an asymmetric shape with respect to the intermediate point X1 of the fin color, and the degree of freedom in layout is increased.

  Since the cross-sectional shape of the fin collar according to the present invention is a non-uniform rational B-spline curve, the range that can be controlled by the control point can be adjusted, and the influence of the control point on the curve can be manipulated. Here, the three control points including the intermediate point of the fin collar intermediate part and both ends of the fin collar intermediate part are controlled by the diameter of the heat transfer tube, the pitch in the stacking direction of the fins, the material of the heat transfer tube and the fin, The shape of the fin collar can be optimized so that the contact gap between the collar and the outer peripheral surface of the heat transfer tube is minimized. Further, X2 and X3 are independent variables, and since the number of spline curves is large, it is possible to create a fin color having an asymmetric shape with respect to the intermediate point X1 of the fin color, and the degree of freedom in layout is increased.

  Moreover, the heat exchanger which concerns on this invention is a cross fin tube type heat exchanger provided with the several fin and the several heat exchanger tube. Each fin has a fin main body having a plurality of through holes and a fin collar formed on the periphery of the through holes. Each heat transfer tube is inserted into the through-hole, and is in close contact with the fin collars of the plurality of fins by expansion. Moreover, the cross-sectional shape of the fin collar is the above-mentioned spline shape.

  Here, by adopting a fin collar whose cross section has a spline shape, the gap between the fin collar and the heat transfer tube after the expansion can be minimized, and the contact pressure can be increased. As a result, the adhesion between the fin and the heat transfer tube is improved, the contact heat transfer coefficient between the fin collar and the heat transfer tube after the expansion is improved, and finally the performance of the entire heat exchanger is improved.

Cross-sectional view of cross fin tube heat exchanger Partial enlarged view of FIG. Simulation model schematic diagram (A) Sectional drawing of the fin collar which concerns on an Example. (B) Dimensional drawing of the fin collar of FIG. (A) The schematic diagram showing the fin color optimization position which concerns on experiment 1. FIG. (B) The schematic diagram showing the shape after fin color optimization which concerns on Experiment 1. FIG. (A) The schematic diagram showing the fin color optimization position which concerns on experiment 2. FIG. (B) The schematic diagram showing the shape after the fin color optimization which concerns on experiment 2. FIG. (A) The schematic diagram showing the fin color optimization position which concerns on experiment 3. FIG. (B) The schematic diagram showing the shape after fin color optimization which concerns on Experiment 3. FIG. (A) The schematic diagram showing the fin color optimization position which concerns on experiment 4. FIG. (B) The schematic diagram showing the shape after fin color optimization which concerns on experiment 4. FIG. (A) The schematic diagram showing the fin color optimization position which concerns on experiment 5. FIG. (B) The schematic diagram showing the shape after the fin color optimization which concerns on Experiment 5. FIG. (A) The schematic diagram showing the fin color optimization position which concerns on experiment 6. FIG. (B) The schematic diagram showing the shape after fin color optimization which concerns on experiment 6. FIG. The graph which shows each experimental result. The L-shaped fin collar schematic diagram whose cross-sectional shape is a straight line. (A) The schematic diagram showing the gap of the fin collar and heat exchanger tube which concern on FIG. (B) The schematic diagram showing the contact stress of the fin collar and heat exchanger tube which concern on FIG. FIG. 3 is a schematic diagram of a fin collar having three bends R.

  A cross fin tube heat exchanger and a heat exchanger fin according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view showing a manufacturing process of a cross-fin tube heat exchanger 100 according to the present invention, and FIG. 2 is a partially enlarged view. As shown in FIGS. 1 and 2, the cross fin tube heat exchanger 100 includes a fin plate 1 and a heat transfer tube 2 arranged in parallel at a predetermined fin pitch. The fin plate 1 has a through hole, and a fin collar 12 is formed on the periphery of the through hole provided in the fin plate 1. The heat transfer tube 2 inserted into the through-hole of the fin plate 1 is expanded by the tube expansion head 3, and the outer peripheral surface of the heat transfer tube 2 and the fin collar 12 are brought into contact with each other. In the contact area between the fin collar 12 and the heat transfer tube 2, heat exchange is performed between the refrigerant flowing through the heat transfer tube 2 and the air W flowing through the surface of the fin plate 1. Here, the heat transfer efficiency of the heat exchanger largely varies depending on the contact state between the fin collar 12 and the heat transfer tube 2 and the size of the contact pressure. In this application, by optimizing the cross-sectional shape of the fin collar as a spline curve, the contact state between the fin collar 12 and the heat transfer tube 2 after the pipe expansion is improved and the contact pressure is optimized, so that the heat exchanger Heat transfer efficiency can be improved.

  In order to verify the effect of optimization of the fin collar cross-sectional shape, the tube expansion process of the cross fin tube heat exchanger was reproduced by a simulation experiment by the finite element method, and the local contact state between the fin collar 12 and the heat transfer tube 2 was reproduced. Examined.

  FIG. 3 is a schematic diagram of a simulation model used for calculating the contact heat transfer coefficient. Since the expansion processing of the cross fin tube has an axially symmetric feature, FIG. 3 will be described using only half of the expansion of the cross fin tube. Here, seven fin plates 1 are stacked, and the movement of the plate portion of the first fin plate and the end fin collar end of the seventh fin plate in the Y-axis direction is restricted from the Y-axis direction. Has been. Moreover, the movement of the both ends of a corresponding heat exchanger tube in the Y-axis direction is restricted. In order to optimize the cross-sectional shape of the fin collar, a non-uniform rational B-spline curve was used in this example. In addition, the optimization target was to minimize the sum of the gap heights between the fin collars 12 and the heat transfer tubes 2 in each part, that is, to minimize the gap area.

  The fin 1 shown in FIG. 4 includes a plate-like fin body portion (11) and an annular fin collar (12) extending in a direction intersecting the fin body portion (11) and having a through hole formed therein. I have. The fin collar (12) includes a fin collar root portion (121) that is a connecting portion with the fin body portion (11), a fin collar intermediate portion (122), and a fin collar reflare portion (123). ing. Here, the distance r between the fin collar intermediate portion (122) and the fin collar central axis Z before the tube expansion is 3.6 mm. As control points of the spline curve, an intermediate point (X1) of the fin collar intermediate part (122), a first end part (X2) of the fin collar intermediate part (122), and a second end part of the fin collar intermediate part (122) ( One or more of X3) were selected, and the variation range was set such that the distance from the fin collar central axis Z was 3.51 to 3.7156 mm.

Here, the following formula was used when calculating the contact heat transfer coefficient.

h-contact heat transfer coefficient, [w / m2k];
λ1-thermal conductivity of aluminum (used for fins), [w / m2k];
λ2-copper thermal conductivity (used for tubes), [w / m2k];
δ1-aluminum surface roughness (used for fins), [μm];
δ2-copper surface roughness (used for tubes), [μm];
H-Hardness of copper, [kgf / mm];
L-the contact length of the fin collar, [mm];
p (l)-contact pressure between fin and tube, [kgf / mm]

<Experiment 1>
In Experiment 1, as shown in FIG. 5A, there is one variation control point as a variable when the cross-sectional shape of the fin collar is optimized. Further, the cross-sectional shape of the fin collar is constituted by a spline curve passing through three points.

  That is, the position of the intermediate point (X1) of the fin collar intermediate part (122) is set as the control point of the spline curve, the intermediate point (X1) of the fin collar intermediate part (122), and the first end of the fin collar intermediate part (122). A spline curve passing through the three points of the portion (X2) and the second end (X3) of the fin collar intermediate portion (122) was created. As a result, the optimized shape shown in FIG. 5B was obtained. Table 1 shows the shape change after optimization in Experiment 1.

<Experiment 2>
In Experiment 2, as shown in FIG. 6A, there is one variation control point as a variable when the cross-sectional shape of the fin collar is optimized. Further, the cross-sectional shape of the fin collar is constituted by a spline curve that passes through five points.

  That is, the position of the intermediate point (X1) of the fin collar intermediate part (122) is set as the control point of the spline curve, the intermediate point (X1) of the fin collar intermediate part (122), and the first end of the fin collar intermediate part (122). A spline curve that passes through the five points of the portion (X2), the second end portion (X3) of the fin collar intermediate portion (122), the predetermined point C1 of the fin collar reflare portion, and the predetermined point C2 of the fin collar root portion was created. As a result, the optimized shape shown in FIG. 6B was obtained. Table 2 shows the change in shape after optimization in Experiment 2.

<Experiment 3>
In Experiment 3, as shown in FIG. 7A, there are three variation control points as variables when optimizing the cross-sectional shape of the fin collar. Further, the cross-sectional shape of the fin collar is constituted by a spline curve that passes through five points.

０＜Ｎ＜１により定義した。また、フィンカラー中間部（１２２）の中間点（Ｘ１）、フィンカラー中間部（１２２）の第１端部（Ｘ２）、フィンカラー中間部（１２２）の第２端部（Ｘ３）、フィンカラーリフレア部の所定点Ｃ１、フィンカラー根元部の所定点Ｃ２の５点を通るスプライン曲線を作成した。その結果、図７（ｂ）に示す最適化後の形状を得ることができた。表３は、実験３における最適化後の形状の変化を表している。 That is, the positions of the intermediate point (X1) of the fin collar intermediate part (122), the second end part (X3) of the fin collar intermediate part (122), and the first end part (X2) of the fin collar intermediate part (122). The control point of the spline curve was used. Where X2 and X3 are

It was defined by 0 <N <1. Further, the intermediate point (X1) of the fin collar intermediate part (122), the first end part (X2) of the fin collar intermediate part (122), the second end part (X3) of the fin collar intermediate part (122), the fin collar A spline curve passing through five points, that is, a predetermined point C1 of the refracted portion and a predetermined point C2 of the fin collar root portion was created. As a result, the optimized shape shown in FIG. 7B was obtained. Table 3 shows the shape change after optimization in Experiment 3.

<Experiment 4>
In Experiment 4, as shown in FIG. 8A, there are three variation control points as variables when optimizing the cross-sectional shape of the fin collar. Further, the cross-sectional shape of the fin collar is constituted by a spline curve that passes through five points.

０＜Ｎ１＜１、０＜Ｎ２＜１により定義した。また、フィンカラー中間部（１２２）の中間点（Ｘ１）、フィンカラー中間部（１２２）の第１端部（Ｘ２）、フィンカラー中間部（１２２）の第２端部（Ｘ３）、フィンカラーリフレア部の所定点Ｃ１、フィンカラー根元部の所定点Ｃ２の５点を通るスプライン曲線を作成した。その結果、図８（ｂ）に示す最適化後の形状を得ることができた。表４は、実験４における最適化後の形状の変化を表している。 That is, the positions of the intermediate point (X1) of the fin collar intermediate part (122), the first end point (X2) of the fin collar intermediate part (122), and the second end point (X3) of the fin collar intermediate part (122) are splined. The control point of the curve was used. Where X2 and X3 are

It was defined by 0 <N1 <1, 0 <N2 <1. Further, the intermediate point (X1) of the fin collar intermediate part (122), the first end part (X2) of the fin collar intermediate part (122), the second end part (X3) of the fin collar intermediate part (122), the fin collar A spline curve passing through five points, that is, a predetermined point C1 of the refracted portion and a predetermined point C2 of the fin collar root portion was created. As a result, the optimized shape shown in FIG. 8B was obtained. Table 4 shows the shape change after optimization in Experiment 4.

<Experiment 5>
In Experiment 5, as shown in FIG. 9A, there are three variation control points as variables when optimizing the cross-sectional shape of the fin collar. Further, the cross-sectional shape of the fin collar is composed of two spline curves passing through two points and one spline curve passing through three points.

０＜Ｎ１＜１、０＜Ｎ２＜１により定義した。また、フィンカラーの断面形状はフィンカラー中間部（１２２）の中間点（Ｘ１）、フィンカラー中間部（１２２）の第１端部（Ｘ２）、フィンカラー中間部（１２２）の第２端部（Ｘ３）の３点を通る第１スプライン曲線、フィンカラーリフレア部（１２３）の所定点（Ｃ１）とフィンカラー中間部（１２２）のフィンカラーリフレア部（１２３）側の第１端部（Ｘ２）の２点を通る第２スプライン曲線と、フィンカラー根元部（１２１）の所定点（Ｃ２）とフィンカラー中間部（１２２）のフィンカラー根元部（１２１）側の第２端部（Ｘ３）の２点を通る第３スプライン曲線とにより構成されている。その結果、図９（ｂ）に示す最適化後の形状を得ることができた。表５は、実験５における最適化後の形状の変化を表している。 That is, the positions of the intermediate point (X1) of the fin collar intermediate part (122), the first end point (X2) of the fin collar intermediate part (122), and the second end point (X3) of the fin collar intermediate part (122) are splined. The control point of the curve was used. Where X2 and X3 are

It was defined by 0 <N1 <1, 0 <N2 <1. Further, the cross-sectional shape of the fin collar includes an intermediate point (X1) of the fin collar intermediate portion (122), a first end portion (X2) of the fin collar intermediate portion (122), and a second end portion of the fin collar intermediate portion (122). The first spline curve that passes through the three points (X3), the predetermined point (C1) of the fin collar reflared portion (123), and the first end portion (X2) of the fin collar intermediate portion (122) on the fin collar reflared portion (123) side ), The second spline curve passing through the two points, the predetermined point (C2) of the fin collar root portion (121), and the second end portion (X3) of the fin collar intermediate portion (122) on the fin collar root portion (121) side. And a third spline curve passing through the two points. As a result, the optimized shape shown in FIG. 9B was obtained. Table 5 shows the shape change after optimization in Experiment 5.

<Experiment 6>
In Experiment 6, as shown in FIG. 10A, there are two variation control points as variables when optimizing the cross-sectional shape of the fin collar. Further, the cross-sectional shape of the fin collar is constituted by two spline curves passing through two points and one spline curve passing through three points.

  That is, the positions of the first end portion (X2) of the fin collar intermediate portion (122) and the second end portion (X3) on the fin collar root portion (121) side were set as control points of the spline curve. Further, the cross-sectional shape of the fin collar includes an intermediate point (X1) of the fin collar intermediate part (122), a first end (X2) of the fin collar intermediate part (122), and a second end of the fin collar intermediate part (122). A first spline curve passing through the three points of the portion (X3), a predetermined point (C1) of the fin collar reflared portion (123), and a first end portion of the fin collar intermediate portion (122) on the fin collar reflared portion (123) side ( A second spline curve passing through two points X2), a predetermined point (C2) of the fin collar root portion (121), and a second end portion (X3) of the fin collar intermediate portion (122) on the fin collar root portion (121) side. ) And a third spline curve passing through two points. As a result, the optimized shape shown in FIG. 10B was obtained. Table 6 shows the shape change after optimization in Experiment 6.

<Conclusion>
FIG. 11 and Table 7 summarize the total reduction rate of the contact gap between the fin collar 12 and the heat transfer tube 2, the increase rate of the maximum contact pressure, and the increase rate of the contact heat transfer rate, which are the results of the above simulation experiments. It is.

  As can be seen from Table 7, in simulation experiments 2, 5, and 6, not only the reduction rate of the total contact clearance is large, but also the increase rate of the maximum contact pressure is large, resulting in an increase of the contact heat transfer rate. The rate is also over 12%.

  On the other hand, as shown in Table 8, in the conventional fin collar, the increase rate of the contact heat transfer coefficient between the fin with the single or two bends R and the heat transfer tube is about 5%. Even if one bend R is attached, and each bend R is contacted smoothly, and the fin collar shape is convex toward the heat transfer tube as a whole so that no straight portion exists, the contact heat transfer coefficient The increase rate is only 9%.

DESCRIPTION OF SYMBOLS 1 Fin 11 Fin main-body part 12 Fin collar 121 Fin collar base part 122 Fin collar intermediate part 123 Fin collar reflare part 2 Heat transfer tube 3 Tube expansion head X1 Intermediate point coordinate X2 of fin collar intermediate part First end coordinate of fin collar intermediate part X3 Second end coordinate C1 of the fin collar intermediate portion C1 Predetermined point coordinate of the fin collar reflare portion C2 Predetermined point coordinate of the fin collar root portion

Japanese Patent No. 3356151

Claims (6)

A fin for a heat exchanger comprising: a plate-like fin main body (11); and an annular fin collar (12) extending in a direction intersecting the fin main body (11) and having a through hole formed therein. In
The fin collar (12) includes a fin collar root portion (121) which is a connecting portion with the fin main body portion (11), a fin collar intermediate portion (122), and a fin collar refractor portion (123). And
The cross-sectional shape of the fin collar (12) is such that the position of the intermediate point (X1) of the fin collar intermediate part (122) is the control point of the spline curve, and the intermediate point (X1) of the fin collar intermediate part (122) The first end portion (X2) of the collar intermediate portion (122), the second end portion (X3) of the fin collar intermediate portion (122), the predetermined point C1 of the fin collar refracted portion, and the predetermined point C2 of the fin collar root portion. A spline curve,
Heat exchanger fins. The cross-sectional shape of the fin collar (12) is formed by continuously connecting a plurality of spline curves,
Among these, the plurality of spline curves are
An intermediate point (X1) of the fin collar intermediate portion (122), a first end portion (X2) of the fin collar intermediate portion (122), and a second end portion (X3) of the fin collar intermediate portion (122). A first spline curve passing through the three points;
A second spline curve passing through a predetermined point (C1) of the fin collar reflared portion (123) and a first end (X2) of the fin collar intermediate portion (122) on the fin collar reflared portion (123) side; ,
A third spline curve passing through a predetermined point (C2) of the fin collar root portion (121) and a second end (X3) of the fin collar intermediate portion (122) on the fin collar root portion (121) side;
The heat exchanger fin according to claim 1, comprising: The plurality of spline curves are non-uniform rational B-splines;
Each of the intermediate point (X1) of the fin collar intermediate part (122), the first end part (X2) of the fin collar intermediate part (122), and the second end part (X3) of the fin collar intermediate part (122). The relationship of coordinates is

Among them, 0 <N1 <1, 0 <N2 <1, C1, C2 are predetermined values.
The heat exchanger fin according to claim 2. A fin for a heat exchanger comprising: a plate-like fin main body (11); and an annular fin collar (12) extending in a direction intersecting the fin main body (11) and having a through hole formed therein. (1) and
A plurality of heat transfer tubes (3) inserted into the through-holes and in close contact with the fin collars (12) of the plurality of fins (1) by pipe expansion;
The cross-sectional shape of the fin collar (12) is such that the position of the intermediate point (X1) of the fin collar intermediate part (122) is the control point of the spline curve, the intermediate point (X1) of the fin collar intermediate part (122), and the fin color A spline that passes through the first end (X2) of the intermediate portion (122), the second end (X3) of the fin collar intermediate portion (122), the predetermined point C1 of the fin collar flared portion, and the predetermined point C2 of the fin collar root portion. Is a curve,
Cross fin tube heat exchanger. The cross-sectional shape of the fin collar (12) is formed by continuously connecting a plurality of spline curves,
Among these, the plurality of spline curves are
An intermediate point (X1) of the fin collar intermediate portion (122), a first end portion (X2) of the fin collar intermediate portion (122), and a second end portion (X3) of the fin collar intermediate portion (122). A first spline curve passing through the three points;
A second spline curve passing through a predetermined point (C1) of the fin collar reflared portion (123) and a first end (X2) of the fin collar intermediate portion (122) on the fin collar reflared portion (123) side; ,
A third spline curve passing through a predetermined point (C2) of the fin collar root portion (121) and a second end (X3) of the fin collar intermediate portion (122) on the fin collar root portion (121) side;
The cross fin tube type heat exchanger according to claim 4, comprising: The plurality of spline curves are non-uniform rational B-splines;
Each of the intermediate point (X1) of the fin collar intermediate part (122), the first end part (X2) of the fin collar intermediate part (122), and the second end part (X3) of the fin collar intermediate part (122). The relationship of coordinates is

Among them, 0 <N1 <1, 0 <N2 <1, C1, C2 are predetermined values.
The cross fin tube heat exchanger according to claim 5.

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