JP2015045455A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger having improved heat transfer coefficient and including a first conduit.SOLUTION: A heat exchanger includes a conduit in which a first coolant flow passage 1a in which first coolant flows is formed. In the first coolant flow passage 1a, projection parts 11a, 11b of which parts in an inner peripheral direction project are formed on an inner wall, and the projection parts are intermittently formed in a flow passage direction 20 of first coolant. In the heat exchanger, since a first coolant flow flowing in the first coolant flow passage 1a is segmented by colliding with the projection parts 11a, 11b, an effect that a temperature boundary layer is made thin is obtained, and heat transfer coefficient can be improved.

Description

  The present invention relates to a heat exchanger that conducts heat exchange between a low-temperature refrigerant other than air and a high-temperature refrigerant to transfer heat from the high-temperature refrigerant to the low-temperature refrigerant.

  A general heat exchanger is a flat pipe which is a conduit in which a first refrigerant flow path through which a first refrigerant flows and a second refrigerant flow path through which a second refrigerant having a temperature different from that of the first refrigerant is formed in parallel. A pipe is provided to exchange heat between the first refrigerant and the second refrigerant (see, for example, Patent Document 1).

  Conventionally, a structure that extends in parallel with the flow direction of the first refrigerant and has a convex portion in which the inner wall of the first refrigerant channel projects inward to increase the heat transfer area and improve the heat transfer coefficient Is disclosed (for example, see Patent Document 2).

JP 2002-340485 A JP 58-64489 A

  As a method for improving the heat transfer coefficient, it is known that it is effective to make the temperature boundary layer of the refrigerant thin. Here, the temperature boundary layer is a region where the temperature of the refrigerant changes suddenly, for example, with respect to a central region that maintains a substantially constant mainstream temperature in the cross section of the flow path of the first refrigerant that flows through the first refrigerant flow path. It refers to a region that rapidly changes from the mainstream temperature to the temperature of the inner wall of the first refrigerant channel toward the inner wall of the first refrigerant channel. In order to make the temperature boundary layer thin, it is effective to obtain the effect of dividing the temperature boundary layer by dividing the flow of the first refrigerant. In the conventional heat exchanger, since the convex portion is formed to extend in parallel with the flow path direction, the shape of the cross section of the flow path is constant in the flow path direction. Therefore, although the effect of enlarging the heat transfer area is obtained, the flow of the first refrigerant is not interrupted, so the effect of thinning the temperature boundary layer cannot be obtained, and the heat transfer coefficient is not sufficiently improved.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a heat exchanger including a first refrigerant flow path with a further improved heat transfer coefficient.

  The heat exchanger according to the present invention includes a conduit in which a first refrigerant flow path through which the first refrigerant flows is formed, and the first refrigerant flow path has a protruding portion protruding partly in the inner circumferential direction on the inner wall. The protrusion is formed intermittently in the flow direction of the first refrigerant.

  According to the heat exchanger according to the present invention, the heat exchanger includes a conduit having a first refrigerant flow path through which the first refrigerant flows, and the first refrigerant flow path has a protruding portion with a part protruding in the inner circumferential direction. Since it is formed on the inner wall and the protrusions are formed intermittently in the flow direction of the first refrigerant, the flow of the first refrigerant is divided, and the temperature boundary layer is thinned. It becomes possible to improve.

It is a perspective view which shows the heat exchanger which concerns on Embodiment 1 of this invention. It is the top view which looked at the heat exchanger which concerns on Embodiment 1 of this invention from the upper surface side. It is the top view which looked at the heat exchanger which concerns on Embodiment 1 of this invention from the bottom face side. It is a side view of the heat exchanger which concerns on Embodiment 1 of this invention. It is sectional drawing of the 1st refrigerant | coolant flow path in the heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which shows the area | region where a 1st refrigerant | coolant flows in the cross section of the 1st refrigerant | coolant flow path of the heat exchanger which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the cross section of the 1st refrigerant | coolant flow path in the downstream of the heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which shows the area | region where a 1st refrigerant | coolant flows in the cross section of the downstream of the 1st refrigerant | coolant flow path of the heat exchanger which concerns on Embodiment 1 of this invention. It is a perspective view which shows a part of cross section along the flow path direction of the 1st refrigerant flow path of the heat exchanger which concerns on Embodiment 1 of this invention. It is a perspective view which shows the method of creating the 1st refrigerant path 1 and the 2nd refrigerant path 2 in the heat exchanger which concerns on Embodiment 1 of this invention. It is a schematic diagram for demonstrating the division | segmentation mechanism of the temperature boundary layer in the heat exchanger which concerns on Embodiment 1 of this invention. It is an enlarged view of a convex part periphery when a refrigerant | coolant is a gas-liquid two-layer fluid in the heat exchanger which concerns on Embodiment 1 of this invention. In the heat exchanger which concerns on Embodiment 2 of this invention, it is a perspective view which shows a part of cross section along the flow path direction of the 1st refrigerant flow path. In the heat exchanger which concerns on Embodiment 2 of this invention, sectional drawing in the flow-path cross section in which the 1st convex part was provided is shown. It is a top view of the heat exchanger which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
First, the structure of the heat exchanger in Embodiment 1 of this invention is demonstrated. FIG. 1 is a perspective view showing a heat exchanger according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of the heat exchanger according to Embodiment 1 of the present invention as viewed from the upper surface side. As shown in FIG. 1, the heat exchanger includes a first refrigerant path 1 configured by arranging a plurality of first refrigerant flow paths 1a in which a first refrigerant flows in a row, and a plurality of second refrigerants in which a second refrigerant flows. The case where the 2nd refrigerant | coolant path | pass 2 comprised by arranging the flow path 2a in a line is formed is demonstrated.

  The first refrigerant flow path 1a and the second refrigerant flow path 2a are arranged in parallel at a predetermined interval, and the first refrigerant path 1 and the second refrigerant path 2 are arranged in parallel. A region between the first refrigerant channel 1a and the second refrigerant channel 2a is referred to as a heat transfer region 9 (shown in FIG. 4).

  In the present embodiment, the first refrigerant path 1 is composed of a plurality of first refrigerant flow paths 1a so as to be surrounded by a dotted line in FIG. 1, but is composed of a single first refrigerant flow path 1a. May be. Further, in the present embodiment, the second refrigerant path 2 is constituted by a plurality of second refrigerant flow paths 2a so as to be surrounded by a one-dot chain line in FIG. 1, but a single second refrigerant flow path 2a. It may consist of.

  Further, in FIG. 1 of the present embodiment, the first refrigerant path 1 is configured by seven first refrigerant flow paths 1a arranged in a line, and the second refrigerant path 2 includes eight second refrigerant flow paths 2a. Are arranged in a line, but the number of each is not limited to this. The number of first refrigerant flow paths 1a and second refrigerant flow paths 2a may be the same, or the number of second refrigerant flow paths 2a may be smaller or larger. That is, it is sufficient that the heat exchanger is configured so that heat exchange can be performed between the first refrigerant flowing through the first refrigerant flow path 1a and the second refrigerant flowing through the second refrigerant flow path 2a. There is no limit to the number. Note that, by determining the number of each refrigerant flow path according to the operating conditions and physical property values of the respective refrigerants of the heat exchanger, a suitable heat exchanger having high heat transfer performance and low pressure loss can be created.

  In FIG. 1, the outer shape of the cross section of the first refrigerant flow path 1a is circular, and the outer shape of the cross section of the second refrigerant flow path 2a is square. However, the shape is not limited thereto. The first refrigerant flow path 1a and the second refrigerant flow path 2a may be through holes formed in the conduit 8, and the outer shape of the cross section may be circular, elliptical, polygonal, or the like. .

  The heat exchanger that constitutes the first refrigerant channel 1a and the second refrigerant channel 2a is made of aluminum, aluminum alloy, copper, copper alloy, steel, stainless alloy steel, or the like.

  The first refrigerant and the second refrigerant are refrigerants other than air, such as liquids, fluorocarbon refrigerants, natural refrigerants such as carbon dioxide or hydrocarbons, and the first refrigerant channel 1a and the second refrigerant channel 2a. Is a through-hole formed in the conduit 8 so that the first refrigerant and the second refrigerant do not leak to the outside.

  In FIG. 1, a first inlet connection pipe 3 that connects the inside and the outside of the heat exchanger is provided on the upstream side of the flow path direction 20 in which the first refrigerant flows in the first refrigerant path 1. A first outlet connecting pipe 4 that connects the inside and the outside of the heat exchanger is provided on the downstream side in the flow path direction 20.

  As shown in FIG. 2, the first inlet communication hole 3a for communicating all the first refrigerant flow paths 1a and the first and second ends of the first refrigerant path 1 shown in FIG. An outlet communication hole 4a is formed. That is, the first inlet communication hole 3 a is provided on the upstream side in the flow path direction 20, and the first outlet communication hole 4 a is provided on the downstream side in the flow path direction 20.

  In the plan view of the heat exchanger in FIG. 2, the first inlet connection pipe 3, the first inlet communication hole 3a, the first refrigerant flow path 1a, the first outlet communication hole 4a, and the first outlet connection are shown for the sake of clarity. The arrangement of the tubes 4 is shown.

  As shown in FIG. 2, the first inlet communication hole 3 a is arranged on the upstream side in the flow path direction 20 so as to communicate with all the first refrigerant flow paths 1 a of the first refrigerant path 1, and the first inlet It is connected to the connecting pipe 3. Similarly, the first outlet communication hole 4 a is arranged to communicate with all the first refrigerant flow paths 1 a of the first refrigerant path 1 on the downstream side in the flow path direction 20, and is connected to the first outlet connection pipe 4. It is connected.

  As shown in FIG. 2, one end of the first inlet communication hole 3a and the first outlet communication hole 4a is connected to the first inlet connection pipe 3 and the first outlet connection pipe 4, respectively, and the other end is a sealing hole. Or is sealed with a sealing member. Further, the through-hole formed as the first refrigerant flow path 1a in the conduit 8 is sealed at both ends on the side surface side from the first inlet communication hole 3a and the first outlet communication hole 4a.

  The first refrigerant flowing through the first refrigerant path 1 is introduced from the outside through the first inlet connection pipe 3 and flows along the introduction direction 21 in the first inlet communication hole 3a. The first refrigerant flowing through the first inlet communication hole 3a flows into the first refrigerant flow path 1a through the communication portion between the first inlet communication hole 3a and each first refrigerant flow path 1a, and the first refrigerant flow It flows along the flow path direction 20 inside the path 1a. The first refrigerant that has flowed to the downstream side of the first refrigerant flow path 1a flows out to the first outlet communication hole 4a through the communication portion between the first refrigerant flow path 1a and the first outlet communication hole 4a, and exit direction 22 and flows out through the first outlet connecting pipe 4.

  An introduction direction 21, a flow path direction 20, and an outlet direction 22 shown in FIG. 1 indicate the direction of the flow of the first refrigerant flowing through the first refrigerant path 1. As will be described later, the direction of the second refrigerant flowing through the second refrigerant path 2 is opposite to the flow of the first refrigerant shown in FIG.

  In FIG. 3, the top view which looked at the heat exchanger which concerns on this Embodiment from the bottom face side is shown. For the sake of clarity, the arrangement of the second inlet connection pipe 5, the second inlet communication hole 5a, the second refrigerant flow path 2a, the second outlet communication hole 6a, and the second outlet connection pipe 6 is shown.

  As shown in FIG. 3, the second inlet communication hole 5 a is arranged on the upstream side in the flow direction 20 of the second refrigerant so as to communicate with all the second refrigerant flow paths 2 a of the second refrigerant path 2, and The second inlet connection pipe 5 is connected. Similarly, the second outlet communication hole 6 a is arranged to communicate with all the second refrigerant flow paths 2 a of the second refrigerant path 2 on the downstream side in the flow path direction 20, and is connected to the second outlet connection pipe 6. It is connected.

  As shown in FIG. 3, one end of the second inlet communication hole 5a and the fifth outlet communication hole 6a is connected to the second inlet connection pipe 5 and the second outlet connection pipe 6, respectively, and the other end is a sealing hole. Or is sealed with a sealing member. The through holes formed in the conduit 8 as the second refrigerant flow path 2a are sealed at both ends on the side surfaces from the second inlet communication hole 5a and the second outlet communication hole 6a.

  In the present embodiment, as shown in FIGS. 2 and 3, the flow direction 20 through which the refrigerant flows is the first refrigerant that flows through the first refrigerant flow path 1a and the second refrigerant that flows through the second refrigerant flow path 2a. And in opposite directions. Thus, the heat exchange efficiency improves because the flow directions of the refrigerants that perform heat exchange are opposed to each other. However, although the heat exchange efficiency is reduced, the heat exchange efficiency may be the same direction instead of facing, and the effect of the present embodiment can be obtained.

  In the present embodiment, the first inlet connecting pipe 3, the first outlet connecting pipe 4, the second inlet connecting pipe 5, and the second outlet connecting pipe 6 are provided on one side of the heat exchanger. It is not limited to this, and it may be provided separately on the top surface, the bottom surface, and the like. Moreover, it may be provided on any of the side surfaces.

  4 is a side view of the heat exchanger of FIG. 1 as viewed from the side where the first inlet connecting pipe 3, the first outlet connecting pipe 4, the second inlet connecting pipe 5, and the second outlet connecting pipe 6 are provided. Show. The flow path direction 20 in FIG. 4 indicates the direction in which the first refrigerant flows. In the present embodiment, a region surrounded by a dotted line in FIG. 4 is called a heat transfer region 9 and corresponds to a region sandwiched between the first refrigerant channel 1a and the second refrigerant channel 2a.

  As shown in FIG. 4, the first inlet connecting pipe 3 and the second outlet connecting pipe 6 and the first outlet connecting pipe 4 and the second inlet connecting pipe 5 are formed with a slight shift in the flow direction 20 of the heat exchanger. Has been. In this way, even if the cross-sectional area of each connecting pipe, that is, the diameter of each connecting pipe is large, the width of the heat transfer region 9 between the first refrigerant flow path 1a and the second refrigerant flow path 2a is reduced. Therefore, heat exchange efficiency can be improved. That is, the distance in the direction perpendicular to the flow path direction 20 between the center of the first outlet connection pipe 4 and the center of the second inlet connection pipe 5 is the radius of the first outlet connection pipe 4 and the second inlet connection pipe 5. Therefore, the width of the heat transfer region 9 corresponding to the distance between the first refrigerant flow path 1a and the second refrigerant flow path 2a can be reduced, and the heat exchange performance is improved. can do.

  As described above, in the heat exchanger according to the present embodiment described with reference to FIGS. 1 to 4, both fluids of the first refrigerant and the second refrigerant exchange heat with the opposite flow through the heat transfer region 9. Has been.

  Next, the 1st refrigerant | coolant flow path 1a which comprises the 1st refrigerant | coolant path | pass 1 is demonstrated. Although the first refrigerant flow path 1a is described as an example in the present embodiment, it goes without saying that the present embodiment can be applied to the second refrigerant flow path 2a as in the case of the first refrigerant flow path 1a. Yes. Further, the first refrigerant may be at a higher temperature than the second refrigerant, or may be at a lower temperature.

  FIG. 5 shows a cross-sectional view of the first refrigerant flow path 1a. 5 corresponds to the AA cross-sectional view in FIG. As shown in FIG. 5, the first convex portion 11a is formed in the cross section of the first refrigerant flow path 1a. That is, the 1st convex part 11a which a part of inner peripheral direction protruded inside is provided in the inner wall of the 1st refrigerant flow path 1a. Here, the inside means the direction toward the center in the cross section of the first refrigerant flow path 1a. In FIG. 5, the inner circumferential direction corresponds to the direction indicated by the arrow.

  In FIG. 5, the flow path direction 20 is the depth direction in the figure, and the portion indicated by the dotted line is the second convex part 11 b provided on the downstream side of the first convex part 11 a in the flow path direction 20. In the present embodiment, as shown in FIG. 5, the first convex portions 11a are provided at four positions at intervals of 90 degrees, and the second convex portions 11b are located downstream of the first convex portions 11a, and the first convex portions 11a. Are arranged in an arrangement rotated 45 degrees in the inner circumferential direction of the flow path cross section.

  FIG. 6 shows a region where the first refrigerant flows in the cross section of the first refrigerant flow path 1a shown in FIG. As shown in FIG. 6, the first protrusion 11 a is provided on the cross section of the first refrigerant flow path 1 a. That is, the region where the first refrigerant flows has a shape in which concave grooves are formed at four locations on the inner wall of the first refrigerant flow path 1a.

  FIG. 7 is a sectional view on the downstream side of the section of the first refrigerant flow path 1a shown in FIG. 7 corresponds to the BB cross-sectional view in FIG. As shown in FIG. 7, a second convex portion 11b is formed in the cross section of the first refrigerant flow path 1a. That is, the inner wall of the first refrigerant flow path 1a is provided with the second convex portion 11b protruding inward.

  In FIG. 7, the flow path direction 20 is the depth direction in the figure, and the portion indicated by the dotted line is the first convex portion 11 a provided on the downstream side of the second convex portion 11 b in the flow path direction 20. In the present embodiment, as shown in FIG. 7, the second convex portions 11b are provided at four positions at intervals of 90 degrees, and the first convex portion 11a further passes through the second convex portion 11b on the downstream side thereof. It is provided in an arrangement rotated by 45 degrees in the inner circumferential direction. In FIG. 7, the inner circumferential direction corresponds to the direction indicated by the arrow.

  FIG. 8 shows a region through which the first refrigerant flows in the cross section of the first refrigerant channel 1a shown in FIG. As shown in FIG. 8, the second convex portion 11 b is provided on the cross section of the first refrigerant flow path 1 a. That is, the region where the first refrigerant flows has a shape in which concave grooves are formed at four locations on the inner wall of the first refrigerant flow path 1a. The concave groove in FIG. 8 is arranged by rotating the concave groove in the cross section of the flow channel shown in FIG. 6 by 45 degrees in the inner circumferential direction.

  Thus, the 1st refrigerant | coolant flow path 1a has a flow path cross section in which the 1st convex part 11a was provided, and a flow path cross section in which the 2nd convex part 1b was provided. As a result, as shown in FIGS. 5 and 7, the first refrigerant flow path 1 a has eight convex portions formed on the inner wall in the inner circumferential direction.

  FIG. 9 is a perspective view showing a part of a cross section along the flow path direction 20 of the first refrigerant flow path 1a. 9 corresponds to a perspective view of the CC cross section in FIG. It can be seen that in the first refrigerant channel 1a, the channel cross section provided with the first convex portion 11a and the channel cross section provided with the second convex portion 11b are alternately arranged. That is, the 1st convex part 11a which the inner wall of the 1st refrigerant | coolant flow path 1a protrudes inward intermittently in the flow path direction 20 is provided. Moreover, the 2nd convex part 11b which the inner wall of the 1st refrigerant | coolant flow path 1a protrudes inward intermittently in the flow path direction 20 is provided.

  With such an arrangement, the first refrigerant flowing from the upstream side in the flow direction 20, that is, the lower side in FIG. 9, collides with the first convex portion 11 a and the second convex portion 11 b, It flows downstream in the direction 20, that is, upward in FIG.

  In other words, in the present embodiment, the convex portion composed of the first convex portion 11a and the second convex portion 11b protruding partially in the inner circumferential direction is intermittently provided in the flow channel direction 20 on the inner wall of the first refrigerant flow channel 1a. Therefore, when the first refrigerant collides with each convex portion, the flow of the first refrigerant flows while being divided.

  Next, the manufacturing method of the heat exchanger in this Embodiment is demonstrated. FIG. 10 is a perspective view showing a method of creating the first refrigerant path 1 and the second refrigerant path 2. A flow path direction 20 in the figure indicates a direction in which the first refrigerant flows.

  As shown in FIG. 10, the first plate 8a and the second plate 8b are alternately stacked along the flow path direction 20, and the bonding surface between the first plate 8a and the second plate 8b is formed. Join by brazing. Here, the flow path cross section of the first refrigerant flow path 1a of the first plate 8a has the shape shown in FIG. 6, and the flow path cross section of the first refrigerant flow path 1a of the second plate 8b is shown in FIG. It is the shape shown. That is, the 1st convex part 11a is provided in the 1st refrigerant | coolant flow path 1a of the 1st plate 8a, and the 2nd convex part 11b is provided in the 1st refrigerant | coolant flow path 1a of the 2nd plate 8b. It has been.

  The first plate 8a is provided with a through hole in which the first convex portion 11a to be the first refrigerant flow path 1a is formed and a through hole to be the second refrigerant flow path 1b. Similarly, the second plate 8b is provided with a through hole in which the second convex portion 11b to be the first refrigerant flow path 1a is formed and a through hole to be the second refrigerant flow path 1b. The plurality of first plates 8a and second plates 8b formed in this manner are arranged so that the positions of the through holes serving as the first refrigerant flow path 1a and the positions of the through holes serving as the second refrigerant flow path 1b. Are stacked in the flow path direction 20 and joined together.

  Conventionally, as a drilling process for forming a plurality of first refrigerant flow paths in a flat pipe integrated from upstream to downstream in the flow path direction, extrusion and drawing processes such as aluminum and copper, which are flat pipes, and A heat exchanger was created by performing post-processing from the block body and adhering flat tubes having a plurality of second refrigerant flow paths in the same manner.

  For this reason, conventionally, it is necessary to form a first refrigerant flow path by drilling so as to penetrate from the upstream to the downstream in the flow path direction, and the flow direction 20 as in the heat exchanger in the present embodiment. It was difficult to provide convex portions intermittently at a plurality of locations. In other words, the convex portions, which are projection groups formed alternately along the flow path direction, are difficult in extrusion or drawing processing of aluminum or copper or the like and post-processing from the block body.

  According to the present embodiment, the first plate 8a and the second plate 8b divided into a plurality in the flow path direction 20 are provided with through holes having the first convex portion 11a and the second convex portion 11b, respectively. The first plate 8a and the second plate 8b are alternately stacked to form the conduit 8 having the first refrigerant flow path 1a. At that time, the positions of the convex portions provided respectively on the first plate 8a and the second plate 8b are formed by rotating in the inner circumferential direction of the flow path cross section, thereby allowing the flow of the first refrigerant flow path 1a. The first convex portion 11 a and the second convex portion 11 b can be easily provided in the road direction 20, and intermittent convex portions can be provided in the flow path direction 20.

  In the conventional method, since the flat tube forming the first refrigerant channel and the flat tube forming the second refrigerant channel are bonded, the first refrigerant channel and the second refrigerant channel. There is a bonding surface between them and voids (bubbles) generated from the adhesive or the like and variations in bonding have been factors in reducing heat transfer performance. That is, the thermal conductivity of the joint surface is reduced, and the heat transfer performance between the first refrigerant and the second refrigerant is reduced.

  In the present embodiment, the first refrigerant channel 1a and the second refrigerant channel 2a are formed by laminating plates in which two rows of through holes are formed in the channel direction 20. Since the through process is performed on the plate divided into a plurality of parts in the flow path direction 20, since the through distance is short, one through hole to be the first refrigerant flow path 1a and one through hole to be the second refrigerant flow path 1b are arranged. It can be formed on one plate. Therefore, there is no bonding surface between the first refrigerant channel 1a and the second refrigerant channel 2a that perform heat exchange. That is, since there is no bonding surface in the heat transfer region 9 that is a heat transfer path, a local decrease in thermal conductivity can be suppressed, and high heat exchanger performance can be obtained.

  In the present embodiment, it is assumed that the same structure as that of the first refrigerant flow path 1a shown in FIG. 9 is adopted for the second refrigerant flow path 2a. In this case, the same effect as that of the first refrigerant flow path 1a can be obtained for the second refrigerant flow path 2a, so that the heat exchange performance is further improved.

  According to this embodiment, since the first convex portion 11a and the second convex portion 11b are provided in the flow path direction 20 of the first refrigerant flow path 1a, the flow of the first refrigerant is divided. As a result, the division of the temperature boundary layer of the first refrigerant is induced and the temperature boundary layer becomes thin, so that the heat transfer performance (heat transfer rate) is improved.

  Here, the temperature boundary layer is a sudden change region of the temperature in the first refrigerant. When there is a temperature difference between the temperature of the first refrigerant and the temperature of the inner wall of the first refrigerant channel 1a in contact with the first refrigerant, the temperature of the first refrigerant is separated from the inner wall of the first refrigerant channel 1a. The main flow temperature is maintained at a constant level, but the temperature rapidly changes as the temperature approaches the first refrigerant flow path 1a, and the first refrigerant flow path 1a is in contact with the inner wall of the first refrigerant flow path 1a. It becomes equal to the temperature of the inner wall.

  The temperature boundary layer is closely related to the heat transfer performance. If the temperature boundary layer becomes thin, the heat transfer coefficient from the first refrigerant to the inner wall of the first refrigerant flow path 1a increases, and the heat exchange performance in heat exchange between the first refrigerant and the second refrigerant improves. .

  In FIG. 11, the schematic diagram explaining the division | segmentation mechanism of a temperature boundary layer is shown. FIGS. 11A and 11B are a schematic diagram of a temperature boundary layer and a heat transfer coefficient when the present embodiment is not used. That is, it is a figure which shows the case where the 1st refrigerant flow path 1a is not provided with the convex part. In FIG. 11A, a temperature boundary layer having a thickness d is generated in the vicinity of the inner wall of the first refrigerant flow path 1a indicated by the solid line from the position x to y where the first refrigerant is introduced. In the figure, the temperature boundary layer is indicated by a two-dot chain line. The temperature boundary layer gradually increases toward the downstream side in the flow path direction 20. Therefore, as shown in FIG. 11B, the heat transfer coefficient decreases from the position x toward the downstream side in the flow path direction 20. In FIG.11 (b), the average value of the heat transfer rate from the position x to the position y is shown with a dotted line.

FIGS. 11C and 11D show the case where this embodiment is used. In FIG. 11C, the first refrigerant introduced from the position x generates a temperature boundary layer having _a thickness da along the inner wall surface of the first convex portion 11a. However, the first refrigerant temperature boundary layer of thickness d _b is newly generated along the position z ₁ from the second convex portion 11b that collides with the second protrusion 11b. Furthermore, collides with the first protruding portion 11a at the position z ₂ on the downstream side, a new temperature boundary layer is generated along the inner wall surface of the first convex portion 11a. Furthermore, collides with the second protrusion 11b at the position z ₃ on the downstream side, new temperature boundary layer is generated along the inner wall surface of the second protrusion 11b.

In this way, the temperature boundary layer is divided every time the refrigerant collides with the convex portion, and the effect of reducing the thickness of the temperature boundary layer is obtained. Heat transfer coefficient in the case of FIG. 11 (c), but decreases when passing through the first convex portion 11a from the position x, it is initialized valued when impinging on the second protrusion 11b at the position z _1. In this way, the fact that the heat transfer coefficient is substantially initialized each time it collides with the convex portion is called a temperature boundary layer dividing effect. Due to this effect, as shown in FIG. 11D, the average value of the heat transfer coefficient of the present embodiment becomes a value of a one-dot chain line, which is improved by Δρ as compared with the case where the present embodiment is not used.

  The dividing effect of the temperature boundary layer is obtained by intermittently forming the convex portions in the first refrigerant flow path 1a.

  In addition, the greater the number of convex portions, the greater the dividing effect. That is, by providing a plurality of convex portions in the inner circumferential direction of the inner wall of the first refrigerant flow path 1a, an effect of uniformly thinning the temperature boundary layer of the inner wall of the first refrigerant flow path 1a is obtained. Thermal properties can be greatly improved. Thus, if this Embodiment is used, it will become possible to improve heat transfer property by the division | segmentation effect of a temperature boundary layer.

  If this Embodiment is used, since the heat-transfer area will expand compared with the case where the 1st refrigerant flow path 1a does not have a convex part, the effect which improves heat exchange performance is also acquired.

  Moreover, the speed of the refrigerant | coolant which flows through convex part vicinity increases by providing a convex part. As the speed of the refrigerant increases, the temperature boundary layer becomes thinner, so that the heat transfer rate is improved and the effect of promoting heat transfer is obtained.

  When the refrigerant is a gas-liquid two-phase fluid, the liquid film portion corresponds to the temperature boundary layer. FIG. 12 shows an enlarged view around the first convex portion 11a when the refrigerant is a gas-liquid two-layer fluid. In the case of a gas-liquid two-phase fluid, as shown in FIG. 12, since the liquid film 15 is sucked to the corner portion by capillary force, the liquid film 15 in the other part is thinned, and the temperature boundary layer is thinned. Heat transfer rate is improved. That is, in the present embodiment, the heat transfer is promoted by the turbulence of the liquid film flow at the first convex portion 11a in the evaporation of the liquid film flow, and the heat transfer is accelerated at the tip of the protrusion by the liquid film removal due to the surface tension in the condensation. An effect is obtained.

It is desirable that the diameters of the first refrigerant flow path 1a and the second refrigerant flow path 2a are small for a fluid having a small viscosity coefficient and large for a fluid having a large viscosity coefficient. From the viewpoints of corrosion and pressure loss of the first refrigerant path 1 and the second refrigerant path 2 of the heat exchanger, it is generally considered that the flow rate of the refrigerant is preferably 0.5 to 1 m / s. The Reynolds number determined from the speed and viscosity of the refrigerant and the length of the flow path is preferably 2000 to 10,000 from the viewpoint of pressure loss and heat transfer characteristics. For example, when the viscosity coefficient is as small as 10 ⁻⁷ m ² / s such as Freon or CO ₂ , the flow path diameter is preferably in the range of 0.5 to 2 mm from the flow velocity and Reynolds number in the above range. Further, in the case of water or the like having a viscosity coefficient as large as 10 ⁻⁶ m ² / s, a desirable flow path diameter obtained in the same manner is 4 to 12 mm.

  If the thickness of the first plate 8a or the second plate 8b is thin, a fine uneven shape can be formed, so that larger heat transfer characteristics can be obtained, but a heat exchanger having the same flow path length is created. In order to do this, the number of stacked layers increases, which increases the manufacturing cost. Therefore, for example, a thickness of about 0.1 to 2 mm is desirable.

  In FIG. 10, the first plate 8a and the second plate 8b having the same thickness are repeatedly laminated, but the present invention is not limited to this. The first plate 8a and the second plate 8b may not have the same thickness. For example, in the configuration as shown in FIG. 10, the first plate 8a may be as thick as three times the second plate 8b.

  Moreover, although the four first convex portions 11a and the second convex portions 11b are provided in the cross section of the flow path, the first convex portions 11a and the second convex portions 11b are not necessarily provided in four locations, and may be provided in one or more locations.

  In the present embodiment, the first convex portion 11a and the second convex portion 11b have a trapezoidal shape that is a tapered shape that narrows inward. However, the present invention is not limited to this. For example, the 1st convex part 11a and the 2nd convex part 11b may be circular, the taper shape which spreads inward may be sufficient, and other polygons etc. may be sufficient.

  In the present embodiment, the first plate 8a provided with the first convex portion 11a and the second plate 8b provided with the second convex portion 11b are alternately stacked to create the conduit 8. The second plate 8b may not be provided with the second convex portion 11b. That is, it is assumed that the first refrigerant flow path 1a of the second plate 8b is not provided with a convex portion, and the flow path cross section has a circular shape without a groove. Even in this case, the first plate 8a is provided with the first convex portion 11a, and the first plate 8a is laminated with the second plate 8b not provided with the second convex portion 11b interposed therebetween. As a result, it is possible to obtain the effect of dividing the temperature boundary layer in the present embodiment.

  That is, the convex part which a part of inner peripheral direction protruded is formed in the inner wall of the 1st refrigerant flow path 1a, and the convex part is intermittently formed in the flow path direction 20 through which the 1st refrigerant flows. For example, the effect of the first refrigerant colliding with the convex portion and dividing the temperature boundary layer can be obtained.

  Furthermore, in this Embodiment, although the angle of the 1st convex part 11a and the 2nd convex part 11b was 45 degree | times, it is not restricted to this. It may be 30 degrees, 60 degrees, or other.

  In the present embodiment, the heat exchanger is created by laminating two kinds of plates, the first plate 8a and the second plate 8b. However, there may be three or more kinds. That is, a heat exchanger may be formed of a plurality of types of plates using a plate having a convex portion provided at a position different from the first convex portion 11a and the second convex portion 11b on the inner wall of the flow path cross section. .

  As a method of laminating the plates, in addition to brazing, diffusion bonding that bonds the metal of the plates may be used.

  In the present embodiment, the heat exchanger in which the first refrigerant path 1 and the second refrigerant path 2 are arranged one by one is shown. However, the first refrigerant path 1 and the second refrigerant path 2 may be alternately arranged in a plurality of lines. Good. That is, the number of arrangements of the first refrigerant path and the second refrigerant path 2 may be increased. By selecting the number of arrays according to the operating conditions and physical property values of the respective refrigerants of the heat exchanger, a suitable heat exchanger having high heat transfer performance and low pressure loss can be created.

  The first inlet connecting pipe 3 and the first inlet communication hole 3a are inserted with pipes having openings such as slits so that only the downstream side of the flow path direction 20 is opened. You may comprise so that it may connect with one refrigerant flow path 1a. Similarly, the first outlet connection pipe 4 and the first outlet communication hole 4a are configured by inserting a pipe having an opening such as a slit so as to open only in the upstream direction of the flow path direction 20. Also good. In this way, when the first refrigerant flow path 1a is sealed from the outside by brazing or the like, it is possible to prevent an excessive brazing material from entering the first inlet communication hole 3a and narrowing the flow path. Manufacturing variation can be suppressed.

  In addition, the same effect can be show | played also if it is set as the same structure also in the 2nd inlet connecting pipe 5, the 2nd inlet communicating hole 5a, the 2nd outlet connecting pipe 6, and the 2nd outlet connecting hole 6a.

Embodiment 2. FIG.
FIG. 13 is a perspective view showing a part of a cross section along the flow path direction 20 of the first refrigerant flow path 1a in the heat exchanger according to the second embodiment. The heat exchanger in the present embodiment is characterized in that the convex portions are arranged in a spiral shape from the upstream side to the downstream side in the flow path direction 20. The rest is the same as in the first embodiment. According to the present embodiment, since the spiral flow of the refrigerant is induced, the effect of increasing the speed of the refrigerant is obtained and the heat transfer coefficient is improved.

  In the present embodiment, as shown in FIG. 13, the first convex portion 11a, the second convex portion 11b, the third convex portion 11c, the fourth convex portion 11d, the fifth convex portion 11e, and the sixth convex portion 11f flow. The first refrigerant flow path 1a is shifted in the path direction 20 and is shifted in the inner peripheral direction of the first refrigerant flow path 1a. That is, it arrange | positions, rotating in order from the upstream of the flow direction 20 toward the downstream to the fixed direction of an inner peripheral direction. As a result, the convex portion is provided in a spiral shape from the upstream side to the downstream side in the flow path direction 20.

  FIG. 14 is a cross-sectional view of the cross section of the flow path provided with the first convex portion 11a. The first convex portions 11a are provided at four positions on the inner wall of the first refrigerant flow path 1a at intervals of 90 degrees, and on the downstream side corresponding to the depth direction in FIG. The part up to 11f is arranged in a spiral.

  FIG. 15 shows a top view of the heat exchanger in the present embodiment. A first plate 8a having a first protrusion 11a, a second plate 8b having a second protrusion 11b, a third plate 8c having a third protrusion 11c, a fourth plate 8d having a fourth protrusion 11d, The 5th plate 8e which has the 5th convex part 11e, and the 6th plate 6f which has the 6th convex part 11f are laminated in order from the upper stream side of the channel direction 20 toward the lower stream side. Therefore, the protrusions formed in a part of the inner circumferential direction of the flow path cross section of the plate are arranged in a spiral shape in the stacking direction of the plates, which is the flow path direction 20, with an interval of the thickness of the adjacent plate. . Thus, the heat exchanger of this Embodiment is easily obtained by laminating | stacking the plate which has each convex part.

  It is difficult to arrange the convex portions in the flow path direction 20 in a spiral manner in the conventional extrusion or drawing processing of aluminum, copper, or the like and post-processing from the block body, and the plate shown in the present embodiment. In the method of forming the flow path by laminating the layers, it can be formed relatively easily.

  In the present embodiment, the effect of dividing the temperature boundary layer by the convex portion and the effect of expanding the heat transfer area are obtained, and the first refrigerant flows in a spiral shape while colliding with each convex portion. That is, by generating a secondary flow such as a spiral swirl flow, the effect of increasing the flow rate of the first refrigerant is obtained, the temperature boundary layer is thinned to promote heat transfer, and the heat transfer rate is improved. .

  In the second embodiment of the present invention, portions different from the first embodiment of the present invention are described, and descriptions of the same or corresponding portions are omitted.

  DESCRIPTION OF SYMBOLS 1 1st refrigerant path, 1a 1st refrigerant flow path, 2nd 2nd refrigerant path, 2a 2nd refrigerant flow path, 3 1st inlet connection pipe, 3a 1st inlet communication hole 3a, 4 1st outlet connection pipe, 4a First outlet communication hole, 5 Second inlet connection pipe, 5a Second inlet communication hole, 6 Second outlet connection pipe, 6a Second outlet communication hole, 8 conduit, 9 heat transfer area, 8a first plate, 8b 2nd plate, 8c 3rd plate, 8d 4th plate, 8e 5th plate, 8f 6th plate, 11a 1st convex part, 11b 2nd convex part, 11c 3rd convex part, 11d 4th convex part, 11e 5th convex part, 11f 6th convex part, 15 liquid film, 20 flow path direction, 21 introduction | transduction direction, 22 exit direction.

Claims (4)

Comprising a conduit formed with a first refrigerant flow path through which the first refrigerant flows;
The first refrigerant flow path has a convex part formed on the inner wall protruding partly in the inner circumferential direction, and the convex part is formed intermittently in the flow direction of the first refrigerant. . The heat exchanger according to claim 1, wherein the first refrigerant flow path includes a plurality of the convex portions in the inner circumferential direction. The heat exchanger according to claim 1, wherein the convex portion is provided in a spiral shape from the upstream side to the downstream side in the flow path direction. The conduit further includes a second refrigerant flow path through which a second refrigerant that exchanges heat with the first refrigerant flows,
The second refrigerant flow path is formed with a convex part protruding from a part in the inner peripheral direction on the inner wall, and the convex part is formed intermittently in the flow direction of the second refrigerant. The heat exchanger according to claim 1, wherein the heat exchanger is a heat exchanger.

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