Heat exchange structure, heat transfer tubes, and heat exchanger

Abstract

The present invention aims to provide a heat exchange structure, heat transfer tubes, and a heat exchanger. [Solution] The heat transfer tube according to the present invention is a heat exchange structure provided in a flow path through which a heat exchange fluid flows, wherein a plurality of radially arranged pin layers are arranged along the length of the flow path, each layer having three or more pins of different lengths arranged radially from the center to the outer circumference of the flow path, and the pins are arranged radially in the circumferential direction of the flow path, wherein the plurality of radially arranged pin layers arranged along the length of the flow path are arranged such that each radially arranged pin layer adjacent to each other in the length of the flow path rotates in the circumferential direction of the flow path, causing the pins of adjacent layers to be misaligned.

Description

Technical Field

[0001] The present invention relates to a heat exchange structure for performing heat exchange with a fluid with low pressure loss and high heat transfer rate, and a heat transfer tube and a heat exchanger equipped with this heat exchange structure.

Background Art

[0002] As a fin-and-tube type heat exchanger for a room air conditioner, as described in Patent Document 1 below, a configuration including a plurality of plate-like fins made of aluminum and a tubular refrigerant pipe made of aluminum inserted through insertion holes provided in each fin is known. In the heat exchanger described in Patent Document 1, a heat conduction part that contacts the refrigerant is provided inside the tube that serves as the refrigerant pipe, and a partition plate that divides the cross section in a direction orthogonal to the longitudinal direction of the tube is provided as this heat conduction part. According to the configuration of Patent Document 1, since the radially provided partition plates contact the refrigerant, the area of contact between the refrigerant and the partition plates is increased, and the heat exchange efficiency is improved.

[0003] Further, in Patent Document 2 below, as an example of an EGR (Exhaust Gas Recirculation) gas cooling device provided in an automobile engine or the like, a plurality of plate-like fins are arranged in parallel on a metal substrate by welding or brazing, and the metal substrate is rounded into a cylindrical shape and adhered to the inner peripheral surface of a heat transfer tube. According to the configuration described in Patent Document 2, by fixing the cylindrical metal substrate to the inner peripheral surface of the heat transfer tube, a plurality of plate-like fins can be arranged at intervals inside the heat transfer tube, so that the heat exchange efficiency with the fluid flowing inside is improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] In the structure described in Patent Document 1, the height of all partition plates along the radial direction of the refrigerant pipe is the same, and there are no additional fins or anything similar in the space between adjacent partition plates in the circumferential direction of the refrigerant pipe. Therefore, even if multiple partition plates are provided in the configuration of Patent Document 1 that come into contact with the refrigerant, the surface area in contact between the partition plates and the refrigerant is not very large, and further improvement in heat exchange efficiency is desired.

[0006] The configuration described in Patent Document 2 illustrates a configuration in which multiple fins of different heights are arranged alternately, but only two types of heights are disclosed. Furthermore, welding or brazing is required to erect the fins, and erecting multiple fins of three or more different heights would mean an increase in the number of fins, making the joining process difficult and thus impractical. Furthermore, with a structure that provides fins of two or so different heights, the spacing between the bases of the fins is wide, resulting in a large area that does not contribute to heat exchange, making it difficult to expect further improvements in heat exchange efficiency.

[0007] Therefore, the inventors considered a configuration in which multiple pins of three or more different lengths are arranged alternately in a radial pattern on the inner wall of a pipe through which a medium flows, and as a result arrived at the present invention.

[0008] The present invention was devised in view of the aforementioned problems, and its purpose is to provide a heat exchange structure that can perform heat exchange with a fluid with low pressure loss and high heat transfer coefficient, and a heat transfer tube and heat exchanger equipped with the heat exchange structure. [Means for solving the problem]

[0009] (1) A heat exchange structure according to one embodiment of the present invention is a heat exchange structure provided in a flow path through which a heat exchange fluid flows, wherein a plurality of pin layers are arranged along the length of the flow path, each of which has three or more pins of different lengths arranged radially from the center to the outer circumference of the flow path and the pins are arranged radially in the circumferential direction of the flow path, characterized in that the plurality of radially arranged pin layers arranged along the length of the flow path rotate in the circumferential direction of the flow path for each radially arranged pin layer adjacent to each other in the length of the flow path, and the pins of adjacent layers are arranged to be misaligned.

[0010] (2) In the heat exchange structure described in (1) of the present invention, it is preferable that the angle between adjacent pins in the radially arranged pin layer is defined as the radiation angle A, and that the radiation angle A is constant, and that the angle of rotation in the circumferential direction of the flow path is defined as the rotation angle B for each radially arranged pin layer adjacent in the longitudinal direction of the flow path, and that the rotation angle B is constant. (3) In the heat exchange structure according to (1) or (2) of the present invention, if the radial arrangement structure of the radial arrangement pin layer is n times symmetric with respect to the circumferential flow path, it is preferable that the rotation angle B is a rotation angle less than 360° / n and an angle other than a multiple of the radiation angle A, where n is a natural number.

[0011] (4) In the heat exchange structure according to any of (1) to (3) of the present invention, if the cross-sectional shape of all pins constituting the radially arranged pin layer is a square of the same size, it is preferable that the distance between adjacent layers along the length of the flow path is small with respect to the side length of all pins constituting the radially arranged pin layer adjacent along the length of the flow path.

[0012] (5) In the heat exchange structure according to any of (1) to (3) of the present invention, if the cross-sectional shape of all pins constituting the radially arranged pin layer is a square of the same size, it is preferable that the distance between adjacent layers along the length of the flow path is small with respect to the thickness value of all the pins constituting the radially arranged pin layer adjacent along the length of the flow path.

[0013] (6) In the heat exchange structure according to any of (1) to (3) of the present invention, it is preferable that the cross-sectional shape of the pin is elliptical. (7) In the heat exchange structure according to any of (1) to (3) of the present invention, it is preferable that the pin has a tapered shape in which the tip closer to the outer circumference of the flow path is thicker and becomes thinner as it approaches the center of the flow path.

[0014] (8) In the heat exchange structure according to any one of (1) to (3) of the present invention, it is preferable to have a reinforcing ring that reinforces all the pins of the radially arranged pin layer. (9) In the heat exchange structure according to any of (1) to (3) of the present invention, in the radially arranged pin layer composed of three or more pins of different lengths, it is preferable that the longest pin among the three or more pins of different lengths is arranged radially so as to extend from the center of the flow path to the outer circumference of the flow path, and the pins of the second and subsequent lengths are arranged radially so as to extend sequentially to the vicinity of the other pins that are longer than the first pin and are closer to the center of the flow path. Furthermore, regarding the pin arrangement of the pin layer, it is preferable that pins of the same length are not adjacent to each other, and that the number of pins is such that the shortest pins are the most numerous and the longest pins are the fewest. (10) In the heat exchange structure according to any of (1) to (3) of the present invention, it is preferable that the area ratio (radial area / inner diameter area of ​​the pipe body) is higher than 0.2 and the number of layers is 7 or more.

[0015] (11) One embodiment of the present invention is a heat transfer tube comprising a plurality of heat exchanger structures described in any of (1) to (3) inside an aluminum tube body that constitutes a flow path for a heat exchange fluid, along the longitudinal direction of the tube body, wherein the pins are made of aluminum, and the outer tip of the pin is joined to the inner wall of the tube body, thereby integrating them. (12) A heat exchanger according to one embodiment of the present invention is characterized by comprising the heat transfer tube described in (11). (13) The heat exchanger according to one embodiment of the present invention includes a plurality of aluminum fins arranged in parallel and an aluminum tube body provided through the plurality of fins. Inside the tube body, a radially arranged pin layer in which aluminum pins of three or more different lengths are arranged radially from the center side to the outer periphery of the tube body and in the circumferential direction of the tube body is arranged at a predetermined interval in the length direction of the tube body. In the plurality of radially arranged pin layers arranged in the length direction of the tube body, the radially arranged pin layers adjacent to each other in the length direction of the tube body are rotated in the circumferential direction of the tube body, and the pins of adjacent layers are arranged so as to be displaced.

Effect of the Invention

[0016] According to one embodiment of the present invention, it is possible to provide a heat exchange structure for performing heat exchange with a fluid with low pressure loss and high heat transfer rate, a heat transfer tube provided with the same, and a heat exchanger.

Brief Description of the Drawings

[0017] [Figure 1] Perspective view showing a heat exchange structure according to a first embodiment of the present invention. [Figure 2] Plan view showing the first-layer radially arranged pin layer constituting the heat exchange structure. [Figure 3] Plan view showing the second-layer radially arranged pin layer constituting the heat exchange structure. [Figure 4] Plan view showing the third-layer radially arranged pin layer constituting the heat exchange structure. [Figure 5] Schematic view when the pins constituting the radially arranged pin layer have a rectangular cross-section. [Figure 6] Schematic view when the pins constituting the radially arranged pin layer have an elliptical cross-section. [Figure 7] Perspective view showing an example of a heat exchanger provided with a heat transfer tube to which the heat exchange structure according to the first embodiment is applied. [Figure 8] Front view showing a part of the heat exchanger. [Figure 9]A plan view showing a heat exchange structure according to a second embodiment of the present invention. [Figure 10] A plan view showing the first radially arranged pin layer constituting a heat exchange structure according to the first embodiment of the present invention. [Figure 11] A perspective view showing an example of a heat exchange structure with a rotation angle of 0°. [Figure 12] A perspective view showing an example of a heat exchange structure with a rotation angle of 9°. [Figure 13] A bottom view showing the radially arranged pin layer in an example of the heat exchange structure with a rotation angle of 0°. [Figure 14] A bottom view showing the radially arranged pin layer in an example of the heat exchange structure with a rotation angle of 9°. [Figure 15] A perspective view showing a heat exchange structure according to the first embodiment of the present invention. [Figure 16] A schematic diagram showing the spacing between pins in adjacent radially arranged pin layers in the heat exchange structure shown in Figure 15. [Figure 17] This figure shows an example of a heat transfer tube in which a heat exchange structure according to the first embodiment is integrated inside the tube body. [Figure 18] A partially enlarged perspective view showing the stacking state of the radially arranged pin layers on the heat transfer tube. [Figure 19] A perspective view showing the rotation angle in a heat exchange structure according to the first embodiment. [Figure 20] A partially enlarged perspective view showing the outer periphery of the heat exchange structure shown in Figure 19. [Figure 21] A schematic diagram showing an example of an elliptical cross-section pin applied to a radially arranged pin layer. [Figure 22] Figure 21 shows an example of a heat transfer tube equipped with a radially arranged pin layer made up of the pins shown. [Figure 23] Figure 21 shows an example of the first layer of the radially arranged pin layer applied to the heat transfer tube. [Figure 24] This is a diagram used to explain a method for manufacturing heat exchange structures using additive manufacturing, and it is an explanatory diagram showing the state in which a powder layer has been formed on a mold. [Figure 25]This is a diagram used to explain a method for manufacturing heat exchange structures using additive manufacturing, and it illustrates the curing process applied to powder layers stacked on a mold. [Figure 26] This is a diagram used to explain the method of manufacturing a heat exchange structure using additive manufacturing, and it is an explanatory diagram showing the green body obtained after curing. [Figure 27] A schematic diagram illustrating heat conduction in a heat exchange structure using a grid layer. [Figure 28] A schematic diagram illustrating heat transfer in a heat exchange structure using radially arranged pin layers. [Figure 29] A schematic diagram illustrating how a 180° rotation returns the pin arrangement of a radially arranged pin layer to its original arrangement. [Figure 30] A perspective view showing an example of a heat transfer tube manufactured in the embodiment. [Figure 31] A perspective view showing the configuration of the heat exchange structure used for evaluation in the example. [Figure 32] A photograph showing an example of a heat exchange structure manufactured and used for evaluation in the examples. [Figure 33] A photograph showing an example of a test specimen with a single-layer reinforcing ring manufactured in the example. [Figure 34] A photograph showing an example of a test specimen with two layers of reinforcing rings manufactured in the example. [Figure 35] A photograph showing an example of a test specimen that was manufactured in the example and exhibited distortion. [Modes for carrying out the invention]

[0018] "First Embodiment" The present invention will be described in detail below based on embodiments, but the present invention is not limited to the embodiments described below. Note that, for convenience, the drawings used in the following description may show enlarged versions of characteristic parts to make the features easier to understand. Figure 1 shows a heat exchange structure S1 according to the first embodiment of the present invention. This heat exchange structure S1 is constructed by stacking nine radially arranged pin layers 1 to 9 of the same shape, with slightly different rotation angles for each layer. In the configuration shown in Figure 1, the radially arranged pin layers 1 to 9 are stacked sequentially from the bottom to the top of the heat exchange structure S1. In Figure 1, the stacking direction of the radially arranged pin layers 1 to 9 is vertical. The heat exchange structure S1 shown in Figure 1 is installed, for example, in a flow path through which a heat exchange fluid flows from its lower surface to its upper surface. That is, the heat exchange structure S1 is installed in a flow path through which a fluid (refrigerant) such as air flows along the direction in which the radially arranged pin layers 1 to 9 are stacked.

[0019] Figure 2 shows the first radially arranged pin layer 1, Figure 3 shows the second radially arranged pin layer 2, and Figure 4 shows the third radially arranged pin layer 3. The fourth radially arranged pin layer 4, the fifth radially arranged pin layer 5, the sixth radially arranged pin layer 6, the seventh radially arranged pin layer 7, the eighth radially arranged pin layer 8, and the ninth radially arranged pin layer 9 are all the same shape, and are integrated into a single structure, differing only in their rotation angles, which will be explained below.

[0020] In the heat exchange structure S1, the first layer from the bottom, the radially arranged pin layer 1, as shown in Figure 2 when viewing the heat exchange structure S1 from the bottom side in Figure 1, has eight longest first pins 15, twelve second longest second pins 16, and twenty third longest third pins 17, which are arranged in parallel radially to form a circle. As shown in Figure 2, a total of 40 pins, including pins 15, 16, and 17, are arranged radially from the center to the outer circumference of the circle. The positions of the pins 15, 16, and 17 will be explained later, but they are arranged so that any of the pins 15, 16, and 17 are arranged radially at equal intervals (constant intervals) around the circumference of the circle drawn at the positions where the tips of the pins 15, 16, and 17 are connected. As the radially arranged pin layer 1 is composed of 40 pins as described above, the 40 pins are arranged radially at 9° intervals in the circumferential direction of the circle. In this embodiment, it is preferable that pins 15, 16, and 17 are all made of aluminum, which has excellent thermal conductivity. In this embodiment, aluminum means pure aluminum or an aluminum alloy. In this embodiment, pins 15, 16, and 17 are all formed as elongated rods having the same square cross-section along their entire length.

[0021] The longest pin 15 has a length that extends from the center of the radially arranged pin layer 1 to the outer edge of the radially arranged pin layer 1. In the example shown in Figure 2, if the circle drawn by connecting the tips 15a of the radially arranged pins 15 is likened to a clock face, the pins 15 are arranged radially at positions 36°, 90°, 126°, 162°, 216°, 270°, 306°, and 342° clockwise from the reference 12 o'clock position. The base end 15b of the pin 15, which is located at the center of the aforementioned circle, is integrated at the center of the circle.

[0022] The second longest pin 16 is arranged radially such that, if the circle drawn by connecting the tips 16a of the radially arranged pins 16 is likened to a clock face, the pins 16 are located at 0°, 18°, 54°, 72°, 108°, 144°, and 180° from the reference 12 o'clock position in a clockwise direction (right-hand). Furthermore, the pins 16 are arranged radially so that they are located at 198°, 234°, 252°, 288°, and 324° from the reference position of the aforementioned circle, in a clockwise direction. The base end 16b of the second longest pin 16 extends from the outer edge of the circle toward the center of the circle. However, since there is a portion at the center of the circle that integrates the base end 15b of pin 15, the base end 16b of pin 16 extends to a position close to (near) the portion that integrates the base end 15b. In the example shown in Figure 1, the base end 16b of pin 16 is positioned near the center of the circle, sandwiched between adjacent pins 15, 15 in the circumferential direction of the circle.

[0023] The third longest pin 17 is arranged radially such that, if the circle drawn by connecting the tips 17a of the radially arranged pins 17 is likened to a clock face, the pins 17 are located at positions 9°, 27°, 45°, 63°, 81°, 99°, 117°, 135°, 153°, and 171° from the reference 12 o'clock position in a clockwise direction (clockwise). Furthermore, the pins 17 are arranged radially so that they are located at 189°, 207°, 225°, 243°, 261°, 279°, 297°, 315°, 333°, and 351°, clockwise from the reference position of the aforementioned circle. Furthermore, the base end 17b of the third longest pin 17 extends from the outer edge of the circle toward the center of the circle. Since the base ends 15b of pin 15 and 16b of pin 16 are located toward the center of the circle, the base end 17b of pin 17 extends to a position close to (near) the base ends of pin 15 and pin 16. It can be described that, relative to pin 15, the second and subsequent pins 16 and 17 extend sequentially towards the center of the longer pins.

[0024] As explained above based on Figure 2, since pins 15, 16, and 17 are arranged radially, when the aforementioned circle is viewed from above, a central channel 1a is formed on the center side of the circle, demarcated by the base end 15b of pin 15 and the base end 16b of pin 16. Furthermore, an internal channel 1b is formed slightly outside the center of the circle, demarcated by the base end of pin 15, the base end of pin 16, and the base end of pin 17. In addition, an external channel 1c is formed outside the internal channel 1b, between pins 15 and 16, between pin 16 and pin 17, and between pins 15 and pin 17, which are adjacent to each other in the circumferential direction of the aforementioned circle.

[0025] In contrast to the first layer of radially arranged pins 1 from the bottom shown in Figure 2, the second layer of radially arranged pins 2 from the bottom is configured as shown in Figure 3. The radially arranged pin layer 2 consists of pins 15, 16, and 17, similar to the radially arranged pin layer 1. The number of pins 15, 16, and 17, and the relationship in which the pins 15, 16, and 17 are arranged around the circumference of the circle formed by the tips of the pins 15, 16, and 17, are also the same as in the radially arranged pin layer 1. As shown in Figure 3, the second radially arranged pin layer 2, viewed from the bottom, has pins 15, 16, and 17 formed at positions rotated 7° clockwise from the 12 o'clock position, which is the reference point when the aforementioned circle is considered as a clock face, relative to the first radially arranged pin layer 1, viewed from the bottom, as shown in Figure 2.

[0026] For example, in the radially arranged pin layer 1 shown in Figure 2, pin 16, which extended in the direction of 12 o'clock, is located in the radially arranged pin layer 2 shown in Figure 3, rotated 7° clockwise from the direction of 12 o'clock. Similarly, the other pins 15, 16, and 17 are formed in positions that are shifted 7° clockwise from their positions in the radially arranged pin layer 1 shown in Figure 2, along the aforementioned circle. Therefore, the second radially arranged pin layer 2 shown in Figure 3 can be described as a rotationally symmetrical body with respect to the first radially arranged pin layer 1 shown in Figure 2, rotated 7° clockwise along the aforementioned circle.

[0027] In contrast to the second radially arranged pin layer 2 shown in Figure 3, the third radially arranged pin layer 3 is configured as shown in Figure 4. The third layer, radially arranged pin layer 3, consists of pins 15, 16, and 17, similar to radially arranged pin layers 1 and 2. The number of pins 15, 16, and 17, and the relationship in which the pins 15, 16, and 17 are arranged around the circumference of the circle formed by the tips of the pins, are also the same as in radially arranged pin layers 1 and 2.

[0028] As shown in Figure 4, the third radially arranged pin layer 3, viewed from the bottom, has pins 15, 16, and 17 formed at positions rotated 7° clockwise from the 12 o'clock position, which is the reference point when the aforementioned circle is considered as a clock face, relative to the second radially arranged pin layer 2, viewed from the bottom, as shown in Figure 3. For example, pin 16, which extended 7° clockwise from the 12 o'clock position in the radially arranged pin layer 1 shown in Figure 3, is located at a position rotated 14° clockwise from the 12 o'clock position in the third radially arranged pin layer 3 shown in Figure 4. Similarly, the other pins 15, 16, and 17 are formed at positions that are shifted 7° clockwise from their positions in the radially arranged pin layer 2 shown in Figure 3, along the aforementioned circle. Furthermore, the third radially arranged pin layer 3 shown in Figure 4 can be described as a rotationally symmetrical body with respect to the first radially arranged pin layer 1 shown in Figure 2, rotated 14° in the clockwise direction of the aforementioned circle. Similarly, the third radially arranged pin layer 3 shown in Figure 4 can be described as a rotationally symmetrical body with respect to the second radially arranged pin layer 2 shown in Figure 3, rotated 7° in the clockwise direction of the aforementioned circle.

[0029] Similarly, for the 4th radially arranged pin layer 4 to the 9th radially arranged pin layer 9, each pin 15, 16, and 17 is formed so that it is sequentially shifted by 7° in the circumferential direction of the aforementioned circle for each layer. For the 4th radially arranged pin layer 4 to the 9th radially arranged pin layer 9, the bottom structure for each layer is not shown in the figure, but as shown in the overall structure of the heat exchange structure S1 in Figure 1, the pins 15, 16, and 17 of each layer are stacked sequentially with a 7° offset relative to the radially arranged pin layer immediately preceding them. For example, in the first radially arranged pin layer 1, the pin 16 extending in the 12 o'clock direction as shown in Figure 2 is positioned in the second radially arranged pin layer 2 at a position rotated 7° clockwise from the 12 o'clock direction of the aforementioned circle, as shown in Figure 3, and in the third radially arranged pin layer 3 at a position rotated 14° clockwise from the 12 o'clock direction of the aforementioned circle, as shown in Figure 4.

[0030] For example, in the fourth to ninth radial array pin layers, the pins 16 of the next layer are also arranged so as to be misaligned by 7° in the circumferential direction off-mentioned circles with respect to the pins 16 of the layer one step ahead sequentially. Regarding the radial array structure of the first to ninth radial array pin layers, when it is a symmetric structure (rotationally symmetric structure) n times around the aforementioned cycles (in other words, cycles around the flow pathways), if the rotation angle(s) are defined as B, it is preferably a rotation angle less than 360° / n and not an angle that is a multiple of the radiation angle A. However, n is a natural number. In addition, in the structure of the present embodiment, as the pin array of the radial array pin layer, it is preferable that pins of the same length do not become adjacent to each other around the cycle, the number of the shortest pins 17 is the largest, the number of the longest pins 15 is the smallest, and the number of the pins 16 with intermediate length is between the number of the pins 15 and the number of the pins 17.

[0031] FIG. 5 shows an example when the cross-sectional shapes of the pins 15, 16, and 17 are rectangular. FIG. 6 shows an example when the cross-sectional shapes of the pins 15, 16, and  17 are elliptical. Regarding the pins 15, 16, and 17, as shown in FIGS. 1 to 4, a square cross-sectional shape may be adopted, or the rectangular cross-sectional shape shown in FIG. 5 or the elliptical cross-sectional shape shown in FIG. 6 may be adopted. Alternatively, other polygonal cross-sectional shapes, irregular cross-sectional shapes, etc. may be adopted. Regardless of the cross-sectional shape adopted, it is preferable that the interval G between adjacent pins in the direction in which a fluid such as air for heat exchange flows is smaller than the thickness D of the pins along the direction in which the fluid for heat exchange flows (the value of the interval G is less than the value of the thickness D). It can be expressed as the relation G<D. In FIG. 5, when the cross-sections of the pins 15, 16, and 17 are rectangular, as an example, the long side is denoted as 0.7 mm and the short side is denoted as 0.3 mm. In FIG. 6, when the pins 15, 16, and 17 are elliptical in cross-section, as an example, the length of the major axis of the ellipse is denoted as 0.3 mm. The thickness of the pins along the length of the flow path is 0.3 mm for pins 15, 16, and 17 shown in Figure 5, and 0.3 mm for pins 15, 16, and 17 shown in Figure 6. If the cross-section of the pin is square, as shown in Figure 1, the thickness is equal to the length of one side of the square.

[0032] Figure 7 shows a heat exchanger 22 comprising a plurality of aluminum plate-shaped fins 20 and a plurality of aluminum heat transfer tubes 21 that are provided to penetrate these fins 20. In this heat exchanger 22, the ends of the heat transfer tubes 21 that penetrate the fins 20 are connected by U-shaped elbow pipes 23, and a meandering flow path is configured using the heat transfer tubes 21 and elbow pipes 23 so that heat exchange can be efficiently performed throughout the entire fins 20. In this heat exchanger 22, the opening of one heat transfer tube 21 that penetrates the upper end of the fins 20 becomes the inlet for the heat exchange fluid, and the opening of the other heat transfer tube 21 becomes the outlet for the heat exchange fluid.

[0033] In the heat exchanger 22 shown in Figure 7, the heat exchange structure S1 shown in Figure 1 is formed intermittently inside the heat transfer tubes 21 in the required number, and is integrated with the heat transfer tubes 21. The number of heat exchange structures S1 provided inside the heat transfer tubes 21 can be any number, and they may be formed to be continuous in the longitudinal direction of the heat transfer tubes 21. As will be described in detail later, the heat transfer tube 21, which has a heat exchange structure S1 inside, can be constructed in which the tips of the pins 15, 16, and 17 are integrated with the inner circumferential surface of the tube body that constitutes the heat transfer tube 21.

[0034] If the heat transfer tube 21 is equipped with a heat exchange structure S1, the pins 15, 16, and 17 of the heat exchange structure S1 are positioned so as to be offset by small angles around the heat exchange structure S1, thereby efficiently disrupting the flow of the heat exchange fluid. This makes it possible to create a heat transfer tube 21 with excellent heat exchange efficiency. Furthermore, three types of pins 15, 16, and 17 of different lengths are provided, and in the radially arranged pin layers 1 to 9, a central channel 1a is provided on the inner circumference side of each, an internal channel 1b is provided on the outside of that, and an external channel 1c is provided on the outside of that.

[0035] As a result, when the fluid passes through the heat exchange structure S1, it can flow along the center of the heat exchange structure S1, along the internal flow path 1b on the outside, and also along the external flow path 1c on the outside. Consequently, the entire length of the pins 15, 16, and 17 provided on the heat exchange structure S1 can be effectively utilized to efficiently exchange heat with the fluid. This improves the heat exchange efficiency in the heat transfer tube 21. Furthermore, since multiple fins 20 are provided in contact with the heat transfer tube 21, heat can be dissipated by utilizing the air surrounding the fins 20. This, combined with the excellent heat exchange characteristics of the heat transfer tube 21, makes it possible to provide a heat exchanger 22 with excellent heat exchange efficiency.

[0036] "Second Embodiment" Figure 9 shows the configuration of the first radially arranged pin layer 30 used in the heat exchange structure of the second embodiment. Similar to the first radially arranged pin layer 1 of the first embodiment shown in Figure 2, the radially arranged pin layer 30 also consists of three types of pins 35, 36, and 37 of different lengths. The radially arranged pin layer 30 has eight first pins 35 which are the longest, twelve second pins 36 which are the second longest, and twenty third pins 37 which are the third longest, and these are arranged in parallel radially to form a circle, which is the same configuration as the radially arranged pin layer 1 of the first embodiment. As shown in Figure 9, the configuration in which a total of 40 pins, including pins 35, 36, and 37, are arranged radially is equivalent to the structure of the first embodiment.

[0037] A characteristic feature of the radially arranged pin layer 30 is that the base end 35b of the pin 35 is the thinnest, and it gradually becomes thicker towards the tip end 35a, with the tip end 35a being the thickest, thus giving it a tapered shape. In addition, the structure in which pins 35, 36, and 37 are arranged radially at equal intervals around the periphery of the radially arranged pin layer 30 is equivalent to the arrangement structure of pins 15, 16, and 17 in the radially arranged pin layer 1 of the first embodiment. For example, if the diameter of pin 35 along the length of the flow path is 0.3 mm, and the diameter of the base end 35b of pin 35 perpendicular to the length is 0.3 mm, then the diameter of the tip end 35a can be 0.7 mm. Similarly, with pin 36, the base end is the thinnest, and it gradually becomes thicker towards the tip end 36a, with the tip end 36a being the thickest. Similarly, with pin 37, the base end 37b is the thinnest, and it gradually becomes thicker towards the tip end 37a, with the tip end 37a being the thickest.

[0038] By sequentially stacking the second to ninth radially arranged pin layers, each having a shape rotated 7° around the periphery of the radially arranged pin layer 30 shown in Figure 9, in the same manner as in the first embodiment, the heat exchange structure of the second embodiment can be constructed. The heat exchange structure of the second embodiment is arranged in the flow path within the tube body of the heat transfer tube, similar to the heat exchange structure S1 of the first embodiment. In other words, the pins 35, 36, and 37 can be described as having a tapered shape, being thicker at the tip closer to the outer circumference of the flow path and becoming thinner as they approach the center of the flow path. In the heat exchange structure of the second embodiment, the same effects and advantages as the heat exchange structure S1 of the first embodiment can be obtained. Furthermore, the heat exchange structure of the second embodiment can be installed inside the tube body to form a heat transfer tube, and a heat exchanger that exhibits the same effects and advantages as the heat exchanger 22 shown in Figure 7 can be obtained using this heat transfer tube.

[0039] Next, we will further describe the detailed structure of a comparative example to the heat exchange structure S1 of the first embodiment described above, using Figures 10 to 14. As shown in Figure 10, in the first radially arranged pin layer 1 applied to the heat exchange structure S1 of the first embodiment, the radiation angle of the first radially arranged pin layer 1 was 9° for all of them. In the first radially arranged pin layer 1, a total of 40 pins, including pins 15, 16, and 17, were arranged radially at equal intervals around the circumference, hence the radiation angle of 9°. In addition, the rotation angle of the radially arranged pin layers from the first to the ninth layers was all the same, set at 7°.

[0040] Assuming that the heat exchange structure S1 is formed using the radially arranged pin layer 1 shown in Figure 10 as described above, and selecting 0° as the rotation angle for each layer as shown in Figure 11, the structure in which the pins of adjacent layers are not misaligned is achieved in the radially arranged pin layer 1 to the radially arranged pin layer 9 of the first to ninth layers. Figure 11 shows the heat exchange structure S2 in which the rotation angle for each layer is set to 0°, so that the pins of the first to ninth layers are aligned in the stacking direction. In contrast, we consider an example where the rotation angle of the radially arranged pin layer is set to 9°. Figure 12 shows a heat exchange structure S3 as an example in which the rotation angle of each layer from the 1st to the 9th layer is set to 9°. At first glance, the heat exchange structure S3 shown as a perspective view in Figure 12 appears to be equivalent to the heat exchange structure S2 shown as a perspective view in Figure 11.

[0041] Figure 13 shows a bottom view of the heat exchange structure S2 with a rotation angle of 0°, and Figure 14 shows a bottom view of the heat exchange structure S3 with a rotation angle of 9°. By comparing the heat exchange structure S2 shown in Figure 13 and the heat exchange structure S3 shown in Figure 14, differences that could not be confirmed by comparing Figures 11 and 12 can be seen. In the heat exchange structure S2, which employs a rotation angle of 0° as shown in Figure 13, the presence of a central channel 1a, an internal channel 1b, and an external channel 1c can be confirmed in the center. That is, in the heat exchange structure S2, it can be seen that the central channel 1a, the internal channel 1b, and the external channel 1c are each individually connected in a straight line along the entire length of the stacking direction of the heat exchange structure S2. In contrast, in the heat exchange structure S3, which employs a rotation angle of 9° as shown in Figure 14, it cannot be seen that the central channel 1a and the internal channel 1b are each individually connected in a straight line along the stacking direction of the heat exchange structure S3.

[0042] Therefore, the heat exchange structure S2 with a rotation angle of 0° and the heat exchange structure S3 with a rotation angle of 9°, which are considered to have equivalent structures when displayed as shown in Figures 11 and 12, can be considered as separate structures. The same can be said for configurations with a rotation angle of 18°, 27°, and subsequent configurations with rotation angles that are multiples of 9°. The same applies to structures with rotation angles of 4.5° and 13.5° (where 13.5° is equivalent to 4.5° + 9°). As will be demonstrated in later embodiments, if the rotation angle is a multiple of the radiation angle, good heat exchange characteristics cannot be obtained; therefore, it is preferable that the rotation angle is an angle other than a multiple of the radiation angle.

[0043] In the case of the heat exchange structure S1 described above, as shown in Figure 1, the radially arranged pin layers 1 to 9, stacked from the 1st to the 9th layer, connect the portions of the external flow channels 1c formed in each layer that have low flow resistance, in a spiral pattern in the thickness direction of the heat exchange structure S1, thereby forming a spiral flow channel. Furthermore, in the internal flow channels 1b formed in each layer, portions with low flow resistance are connected in a spiral pattern in the thickness direction of the heat exchange structure S1, forming a spiral flow channel. Furthermore, in the central flow channels 1a formed in each layer, portions with low flow resistance are connected in a spiral pattern in the thickness direction of the heat exchange structure S1, forming a spiral flow channel. With this configuration of the heat exchange structure S1, the fluid can flow in a near-spiral shape on the central, internal, and external sides of the heat exchange structure S1, which is expected to improve the heat exchange efficiency with the fluid. This spiral flow effect cannot be obtained when the number of layers is small, so a number of layers of 7 or more is preferable. Furthermore, it is preferable that the area ratio between the projected area of ​​the radial structure in one layer when the radially arranged pin layer is viewed from the front side from the direction through which the fluid flows and the inner diameter area of ​​the pipe body having the radial structure inside is greater than 0.2, as this indicates a large heat exchange area.

[0044] Figure 15 shows the same heat exchange structure S1 as shown in Figure 1, but Figure 16, drawn in comparison to Figure 15, shows the pins 15, 16, and 17 provided on the heat exchange structure S1 viewed from the side. As shown in Fig. 16, when pins 15, 16, and 17 are slender rod-shaped with a square cross-section, the thickness D of each pin can be selected as 0.3×0.3 mm as shown in the previous example. In this case, the interval G between adjacent radially arranged pin layers can be selected to be 0.15 mm. It is preferable that the relationship is G < D.

[0045] Fig. 17 shows a heat transfer tube 41 having a structure in which a heat exchange structure S4 made of aluminum is integrated inside a tube body 40 made of aluminum. Inside the tube body 40, the heat exchange structure S4 may be arranged intermittently at a predetermined interval in the length direction of the tube body 40, or the heat exchange structure S4 may be arranged continuously along the length direction of the tube body 40.

[0046] The heat exchange structure S4 shown in Fig. 17 includes radially arranged pin layers of the 1st to 9th layers having pins 15, 16, and 17 with the same structure as the heat exchange structure S1 of the first embodiment shown in Fig. 1. However, in the heat exchange structure S4, in order to increase the structural strength of the pins 15, 16, and 17, reinforcing rings 42 that individually connect the pins 15, 16, and 17 in a bridging manner are provided at the inner peripheral portions of each radially arranged pin layer. Fig. 18 shows a state in which a plurality of radially arranged pin layers constituting the heat exchange structure S4 are arranged intermittently in the length direction of the tube body 40 and are displaced while maintaining a predetermined rotation angle.

[0047] In the heat transfer tube 41, since the aluminum constituting the tube body 40 and each of the pins 15, 16, and 17 has excellent thermal conductivity, by flowing a fluid through the heat transfer tube 41 shown in Fig. 17, excellent heat exchange characteristics can be obtained. Moreover, since the heat transfer tube 41 is provided with the heat exchange structure S4, the flow of the heat exchange fluid can be efficiently disturbed in the same manner as the heat transfer tube 21 using the heat exchange structure S of the first embodiment. As a result, a heat transfer tube 41 with excellent heat exchange efficiency can be obtained.

[0048] FIG. 19 shows the same heat exchange structure S1 as the heat exchange structure S1 shown in FIG. 1, and FIG. 20 drawn in comparison with FIG. 19 shows an enlarged view of the rotation angles of the pins 15, 16, and 17 provided on the heat exchange structure S1. In the heat exchange structure S1 shown in these figures, if the rotation angle of each pin is denoted as B, the rotation angle B can be expressed by the following formula. B=(n - 1)×A + C In this formula, n is an integer of 1 or more, A is the radiation angle (9° in the case of the first embodiment), and 0 < C < A. As an example, when n = 1, it is preferable that the rotation angle E satisfies the relationship of 0 < B < 9°, and when n = 2, it is preferable that the rotation angle E satisfies the relationship of 9 < B < 18°.

[0049] FIG. 21 shows the pins 55, 56, and 57 in the case of an elliptical cross section, and FIG. 22 shows a heat transfer tube 51 in which a heat exchange structure S5 that can be configured when using these pins 55, 56, and 57 is integrated inside a tube body 50. The arrangement shape of the first pin 55, the second pin 56, and the third pin 57 and the relationship of the lengths of each pin may be the same as those of the radial arrangement pin layers 1 to 9 of the first to ninth layers and the first pin 15, the second pin 16, and the third pin 17 described in the first embodiment. For the sake of illustration in FIG. 23, an example of the arrangement of the pins 55, 56, and 57 in the radial arrangement pin layer 58 of the first layer is shown. As an example of the size of the cross section of the pins 55, 56, and 57, it is an elliptical cross-sectional shape, and the length of the long axis of the ellipse can be selected as 0.3 mm and the length of the short axis as 0.2 mm. In the heat transfer tube 51 shown in FIG. 22, the same operational effects as those of the heat transfer tube 21 described in the first embodiment can be obtained.

[0050] "Regarding the manufacturing method" The heat exchange structure S1 having the configuration described above can be manufactured by a binder jet type additive manufacturing method using metal powder and a 3D printer. For example, when manufacturing a lattice-like structure using additive manufacturing, as shown in Figure 24, one layer of metal powder particles 61 is deposited on a powder bed 60, and binder ink 63 is applied from the inkjet printer head 62 according to the shape to be manufactured. Next, a second layer of metal powder particles is deposited on the powder bed 60, and binder ink is applied to the necessary areas. The above process is repeated the required number of times to form a laminate 66 of the required thickness as shown in Figure 25.

[0051] After this, curing is performed and the layered material 66 is dried in a drying oven. After drying, the molded object (green body) 67 shown in Figure 26 is removed from the powder and the molded object 67 is separated from the metal powder particles 61 that are not coated with binder ink 63. After degreasing the separated molded object 67, it is placed in a heating furnace and heated to the required temperature to sinter it, thereby obtaining a sintered body of the desired shape. For example, by sintering the molded object 67 shown in Figure 26, a lattice-shaped structure 68 shown in Figure 27 can be obtained.

[0052] Figure 28 shows the radially arranged pin layer 1 to be manufactured in this embodiment. Using the additive manufacturing method described in Figures 24 to 26, binder ink is appropriately scattered onto the stacked metal powder particle layers according to the planar shape of the desired radially arranged pin layer 1. The metal powder particles coated with binder ink are sequentially stacked to the required thickness, and then curing, degreasing, and sintering are performed to form the radially arranged pin layer 1 shown in Figure 28. In this embodiment, it is desirable to deposit nine radially arranged pin layers. By repeatedly performing the binder jet type additive manufacturing method described above until a thickness of nine layers is achieved, the heat exchange structure S1 shown in Figure 1 can be manufactured. For example, each radially arranged pin layer can be fabricated by performing additive manufacturing with a layer thickness of several tens of micrometers or more per layer using a general commercially available 3D printer.

[0053] Furthermore, if the tube body is manufactured simultaneously with the heat exchange structure S1 using a binder jet additive manufacturing method, a heat transfer tube 41 can be manufactured in which the heat exchange structure S1 is integrated inside the tube body 40, as explained earlier based on Figure 17. By using a binder jet additive manufacturing method, the heat exchange structure S1 can be manufactured independently, and if necessary, a heat transfer tube 41 can also be manufactured in which the heat exchange structure S1 is integrated into the tube body 40.

[0054] Furthermore, comparing the heat conduction of the lattice-like structure 68 shown in Figure 27 and the radially arranged pin layer 1 shown in Figure 28, it is thought that the thermal resistance is large in the structure 68 because heat is conducted in a zigzag pattern along the lattice. However, in the radially arranged pin layer 1 shown in Figure 28, heat is conducted linearly through one of the pins 15, 16, or 17, and heat is conducted over the shortest distance, so it is thought that heat can be transferred to the heat exchange fluid more efficiently.

[0055] Figure 29 shows the first layer of radially arranged pins 1, which was previously described in Figure 2. Considering the rotational symmetry of the radially arranged pins 1 based on Figure 29, it can be seen that the first layer of radially arranged pins 1 returns to its original planar shape when rotated 180° clockwise or counterclockwise. [Examples]

[0056] The following describes embodiments of the present invention, but the present invention is not limited to the following embodiments. A simulation was conducted to calculate the pressure loss and heat transfer coefficient of a heat transfer tube (outer diameter 21 mm, inner diameter 18 mm, length 27 mm) 71, which is constructed by integrating a heat exchange structure S1 similar in structure to the heat exchange structure shown in Figure 1 inside an aluminum tube body 70 as shown in Figure 30. Assuming an outer wall temperature of 140°C and air flowing into the heat transfer tube 71 (25°C, 50 L / min), the simulation software used to calculate the heat transfer coefficient and pressure loss was Ansys 2022 R2, coupled analysis software from ANSYS. The simulation conditions applied were element size of 0.1 mm or less, polyhedral meshing, more than 1000 iterations, Transition SST viscosity model, and the SIMPLE method. In conducting the simulation, as shown in Table 1 below, the following variables were used to calculate the heat transfer coefficient, pressure loss, Nu (Nusselt number), f (friction loss coefficient), and TPE (Thermal Performance Factor): pin shape, pin length (mm), radiation angle (°), rotation angle (°), pin thickness (mm), spacing between layers (mm), presence or absence of reinforcing rings, number of layers, and area ratio (radial area / inner diameter area of ​​the pipe body). The lengths of the pins, from longest to shortest, are 9mm, 8mm, 6mm, and 3mm in Example No. 10; 9mm, 8mm, and 6mm in Examples No. 1-9, 11, and 12, and Comparative Examples 1 and 2; and 9mm and 8mm in Comparative Example No. 3. The 9mm long pins are all located at 36°, 90°, 126°, 162°, 216°, 270°, 306°, and 342° from the reference 12 o'clock position, clockwise. The 8mm long pins are all located at 0°, 18°, 54°, 72°, 108°, 144°, 180°, 198°, 234°, 252°, 288°, and 324° from the reference 12 o'clock position. Each 6mm long pin starts at a position 9° clockwise (right-hand) from the reference 12 o'clock position and is placed every 18°. The 3mm long pins start at 4.5° clockwise (right-hand) from the reference 12 o'clock position and are placed every 9°.

[0057] The Nusselt (Nu) number was calculated from the pressure loss, and the figure of performance (TPE) was evaluated using the following formula. Heat transfer tubes that have low pressure loss, high heat transfer coefficient, and perform good heat exchange tend to have higher TPF values. TPF=Nu / f (1 / 3) The simulation results for heat exchange structures No. 1 to No. 15, with the variable settings shown in Table 1, are also shown in Table 1 below. No. 8 has a tapered shape where the base of the pin is the thinnest, and it gradually becomes thicker towards the tip, with the tip being the thickest. The thickness of the pin along the length of the flow path is 0.3 mm, and the thickness of the base of the pin perpendicular to the length is 0.3 mm, while the thickness of the tip is 0.7 mm.

[0058] [Table 1]

[0059] As shown in Table 1, the heat transfer tubes of Examples No. 1 to 12 all met the desirable conditions for the number of pin lengths, radiation angle, and rotation angle, resulting in excellent heat transfer coefficients and good values ​​for the thermal performance index (TPE). Compared to these heat transfer tubes, the heat transfer tube of Comparative Example No. 1 with a rotation angle of 0° and the heat transfer tube of Comparative Example No. 2 with a rotation angle of 90° both showed lower pressure loss, but lower heat transfer coefficients and lower heat transfer performance indices compared to the aforementioned heat transfer tubes. The heat transfer tubes in Comparative Example No. 3 had two types with different pin lengths. Even when the radiation angle, rotation angle, pin thickness, spacing between layers, and number of layers were set to the same desirable conditions as the aforementioned heat transfer tubes, they showed a low heat transfer coefficient and a low heat transfer performance index.

[0060] These results show that if a heat transfer tube is used that satisfies the desirable relationship between radiation angle and rotation angle described in the previous embodiment, it is possible to obtain a heat transfer tube that exhibits excellent heat transfer coefficient and a good value for the heat transfer performance index.

[0061] A prototype test was conducted to manufacture a heat exchange structure shown in Figure 1, which consists of nine radially arranged pin layers stacked using a binder jet additive manufacturing method with aluminum powder and a 3D printer, as shown in Figure 2. A heat exchange structure was prototyped using additive manufacturing, with the first, second, and third pins formed into rectangular rod shapes with a thickness of 0.3 x 0.3 mm, a rotation angle of 7° per layer in the radially arranged pin layers from the 1st to the 9th layer, and a total of 40 pins of the three types, resulting in a radial angle of 9°. Figure 32 shows the heat exchange structure obtained from the prototype. In this prototype, as shown in Figure 31, a circular through-hole 81 was made in the center of a plate-shaped base 80, and the heat exchange structure S1 occupied the inside of this through-hole 81. As shown in Figure 32, we were able to manufacture a heat exchange structure with a structure in which multiple pins having the desired shape are arranged.

[0062] Figure 33 shows an example of a heat exchange structure obtained by prototyping a heat exchange structure S4 equipped with the reinforcing ring 42 shown in Figure 17 using a binder jet additive manufacturing method. Figure 34 shows another example of a heat exchange structure obtained by prototyping a heat exchange structure with two reinforcing rings, in contrast to the example of a heat exchange structure shown in Figure 33. As shown in Figures 33 and 34, a heat exchange structure with a reinforcing ring was manufactured using a binder jet additive manufacturing method.

[0063] Figure 35 shows the heat exchange structure that exhibited distortion as a result of fabricating multiple prototypes of the heat exchange structure with the configuration shown in Figure 32. In binder jet additive manufacturing, aluminum powder is layered and then sintered. Depending on the bonding state of the powders during sintering, it is possible that distortion may occur in the elongated pins, as shown in Figure 35. Multiple prototypes were manufactured with the reinforcing rings shown in Figures 23 and 24, but none of them showed any distortion in the pins, as shown in Figure 35. This indicates that when manufacturing a heat exchange structure with many elongated rod-shaped pins, it is important to include a structure that reinforces the pins. [Explanation of Symbols]

[0064] S1... Heat exchange structure, 1, 2, 3, 4, 5, 6, 7, 8, 9... Radially arranged pin layers, 1a...Center side flow path, 1b...Inner side flow path, 1c...Outer side flow path, 15...1st pin, 16...2nd pin, 17...3rd pin, 20...fins, 21...heat transfer tubes, 22...heat exchanger 30...Radial arrangement of pins, 35...First pin, 36...Second pin, 37...Third pin 40...tube body, 41...heat exchanger tube, S4...heat exchange structure, 50...Tube body, 51...Heat transfer tube, S5...Heat exchange structure, 58...Radial arrangement pin layer, 70...Tube body, 71...Heat transfer tube.

Claims

1. Installed in the flow path through which the heat exchange fluid flows, A heat exchange structure is provided in which multiple radially arranged pin layers, each consisting of three or more pins of different lengths arranged radially from the center to the outer circumference of the flow path and radially in the circumferential direction of the flow path, are arranged along the length of the flow path. A heat exchange structure characterized in that, in a plurality of radially arranged pin layers arranged in the longitudinal direction of the flow path, each radially arranged pin layer adjacent to the flow path rotates in the circumferential direction of the flow path, and the pins of adjacent layers are arranged to be misaligned.

2. The heat exchange structure according to claim 1, characterized in that the angle between adjacent pins in the radially arranged pin layer is defined as the radiation angle A, and the radiation angle A is constant, and the angle of rotation in the circumferential direction of the flow path for each radially arranged pin layer adjacent in the longitudinal direction of the flow path is defined as the rotation angle B, and the rotation angle B is constant.

3. The heat exchange structure according to claim 2, characterized in that, when the radial arrangement structure of the radial arrangement pin layer has an n-fold symmetric structure around the circumferential flow path, the rotation angle B is a rotation angle less than 360° / n and is an angle other than a multiple of the radiation angle A. However, n is a natural number.

4. If the cross-sectional shape of all the pins constituting the radially arranged pin layer is a square of the same size, The heat exchange structure according to any one of claims 1 to 3, characterized in that the spacing between adjacent layers along the length of the flow path is small relative to the length of one side of all the pins constituting the radially arranged pin layer adjacent along the length of the flow path.

5. If all the pins constituting the radially arranged pin layer have the same cross-sectional shape and the same size, The heat exchange structure according to any one of claims 1 to 3, characterized in that the spacing between adjacent layers along the length of the flow path is small compared to the thickness of all the pins constituting the radially arranged pin layer adjacent along the length of the flow path along the length of the flow path.

6. The heat exchange structure according to any one of claims 1 to 3, characterized in that the cross-sectional shape of the pin is elliptical.

7. The heat exchange structure according to any one of claims 1 to 3, characterized in that the pin has a tapered shape, with the tip closer to the outer circumference of the flow path being thicker and becoming thinner as it approaches the center of the flow path.

8. The heat exchange structure according to any one of claims 1 to 3, further comprising a reinforcing ring that reinforces all the pins of the radially arranged pin layer.

9. The heat exchange structure according to any one of claims 1 to 3, wherein the radially arranged pin layer is composed of three or more pins of different lengths, the longest pin among the three or more pins of different lengths is arranged radially so as to extend from the center of the flow path to the outer circumference of the flow path, and the pins of the second and subsequent lengths are arranged radially so as to extend sequentially to the vicinity of the other pins that are longer than the first pin, closer to the center of the flow path.

10. A heat exchange structure according to any one of claims 1 to 3, wherein the area ratio (radial area / inner diameter area of ​​the pipe body) is higher than 0.2 and the number of layers is 7 or more.

11. A heat transfer tube characterized in that a plurality of heat exchange structures according to any one of claims 1 to 3 are provided inside an aluminum tube body that constitutes a flow path for a heat exchange fluid, along the longitudinal direction of the tube body, the pins are made of aluminum, and the pins are integrated with the tube body.

12. A heat exchanger characterized by comprising the heat transfer tube described in claim 11.

13. It comprises multiple aluminum fins arranged in parallel and an aluminum tube body that penetrates through the multiple fins, Inside the tube body, multiple radially arranged pin layers are provided at predetermined intervals along the length of the tube body, with three or more aluminum pins of different lengths arranged radially from the center of the tube body toward the outer circumference, and the pins arranged radially in the circumferential direction of the tube body. A heat exchanger characterized in that, in a plurality of radially arranged pin layers arranged in the longitudinal direction of the tube body, each radially arranged pin layer adjacent to the tube body rotates in the circumferential direction of the tube body, and the pins of adjacent layers are arranged to be misaligned.

Images