JP2004191034A - Heat transfer pipe internally provided with fin member made of resin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a heat transfer pipe having thermal conductivity equal to that of a heat transfer pipe made only of metal materials by using resin materials, and to enable easy manufacturing of the lightweight and inexpensive heat transfer pipe with high corrosion resistance. <P>SOLUTION: Cylindrical fin members 3 made of resin materials are formed by projectingly providing a plurality of fins on an inner peripheral face of a base board 4. The heat transfer pipe 1 is formed by arranging one or the plurality of the cylindrical fin members 3 made of resin materials in series inside a metal pipe 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a heat exchanger for cooling water, cooling air, a refrigerant for a car air conditioner, and other cooling media, and a combustion exhaust gas containing EGR gas and soot in a multi-tube heat exchanger such as an EGR gas cooling device. The present invention relates to heat transfer tubes for various uses such as those used for replacement.

  Conventionally, in an engine of an automobile, an EGR system in which a part of exhaust gas is taken out from an exhaust gas system, returned to an intake system of the engine, and added to an air-fuel mixture or intake air has been used for both a gasoline engine and a diesel engine. . EGR systems, especially cooled EGR systems with high EGR rates for diesel engines, reduce NOx in exhaust gas to prevent deterioration of fuel efficiency and prevent deterioration of EGR valve function and durability due to excessive temperature rise. For this purpose, an EGR gas cooling device is provided for cooling the EGR gas at a high temperature with cooling water, cooling air, a refrigerant for a car air conditioner, or another refrigerant liquid.

  As the EGR gas cooling device, a plurality of small-diameter heat transfer tubes through which EGR gas can flow are disposed as shown in the conventional invention of Patent Document 1 below, and cooling water or cooling air is provided outside the heat transfer tubes. In some cases, heat is exchanged between the EGR gas and the cooling medium through a heat transfer tube by flowing a cooling medium such as a refrigerant.

As a heat transfer tube used in the above-described EGR gas cooling device, those described in Patent Document 1 and Patent Document 2 below are known. These heat transfer tubes are formed by installing a long plate-shaped or spiral metal fin member in the tube axis direction inside the metal tube, and the fin member increases the heat transfer area of the heat transfer tube. By making the flow of the EGR gas in the heat transfer tube turbulent, the heat exchange efficiency between the EGR gas and the cooling medium is increased through the heat transfer tube.
JP-A-11-108578 JP 2001-227413 A

  However, metal materials are more expensive and less workable than resin materials, so the shape of conventional metal fin members is limited, and it is difficult to form a complex shape with a large surface area and excellent heat dissipation. However, there was a limit to weight reduction. Also, in order to obtain corrosion resistance to water vapor, unburned gas, sulfuric acid, and condensate such as hydrocarbons in the EGR gas, it is necessary to perform plating or the like, and it is troublesome to braze the fin members. Was increasing. Therefore, the present inventors focused on a resin material that is lightweight and excellent in workability, and conducted a comparative experiment of heat exchange performance between a heat transfer surface made of a metal material and a heat transfer surface made of a resin material. It has been found that the heat exchange surface made of a resin material deteriorates only about 4 to 15% in heat exchange performance as compared with the heat transfer surface made of a resin material, depending on conditions. In order to supplement the heat exchange performance of about 4 to 15%, if the surface area of the resin material heat transfer surface is increased by 15% or more, heat exchange performance equal to or greater than that of the metal heat transfer surface can be obtained. I came to the conclusion that I could get it.

  An object of the present invention is to solve the problems as described above. A heat transfer tube is formed by mounting a resin material fin member inside a thinned metal tube, thereby reducing the weight and cost of the heat transfer tube. In addition to the above, the surface area of the resin fin member is increased by the excellent workability of the resin material, and the same thermal conductivity as that of the metal fin member is obtained. The excellent heat conductivity improves the heat exchange efficiency between the fluid flowing in the heat transfer tube and the heat exchange medium flowing on the outer surface of the heat transfer tube. The excellent heat exchange performance makes it possible to reduce the weight and size of the heat transfer tube and the multi-tube heat exchanger using the heat transfer tube.

  In order to solve the above-described problems, the present invention is configured by arranging one or more cylindrical resin fin members having a plurality of fins protruding from an inner peripheral surface of a substrate in a metal pipe in series or in series. is there.

  The resin fin member may have a plurality of fins integrally projecting from the inner peripheral surface of a cylindrical substrate having no joint in the circumferential direction.

  The resin fin member is formed by integrally projecting a plurality of fins on one surface of a strip-shaped substrate, forming the substrate into a cylindrical shape with the one surface on which the fins are provided inside, and contacting both end edges of the substrate with each other. The cylindrical fin member made of a resin material may be brought into contact with the fin member.

  Further, the fin may be a pin-like fin and / or a plate-like fin.

  Further, the plate-like fins may be provided with a turbulence generating means composed of any one or a plurality of protrusions, through holes, irregularities, pins, and ridges.

  Further, the pin-shaped fins and / or the pin-shaped turbulence generating means may have a circular, elliptical, polygonal, star-shaped, or gear-shaped cross section.

  The resin fin member may contain particles and / or fibers having higher thermal conductivity than the resin material forming the resin fin member.

  The resin fin member may include carbon nanofibers in a resin material forming the resin fin member.

  Further, the carbon nanofibers may be contained at a content of more than 5 wt% and less than 30 wt%.

  The present invention is configured as described above, and since the heat transfer tube is formed by mounting the resin material fin member in the metal tube, the heat transfer of the fin member is performed by utilizing the excellent workability of the resin material. The area can be increased, and a heat transfer tube having the same thermal conductivity as a heat transfer tube formed only of a metal material can be obtained. In addition, by using a resin material, the heat transfer tube can be easily manufactured, a cheap and lightweight heat transfer tube can be obtained, and the heat transfer tube has excellent corrosion resistance. Therefore, by using such a heat transfer tube that is excellent in heat exchange efficiency and lightweight and inexpensive, the heat exchange performance of the EGR gas cooling device and other multi-tube heat exchangers can be improved, and the product quality can be improved. As a result, the durability of the product is improved due to the excellent corrosion resistance. In addition, due to the excellent heat exchange performance, it is possible to reduce the size and weight of the multi-tube heat exchanger, and the product has a high degree of freedom in layout when installed in a vehicle or the like.

  As described above, the heat transfer tube of the present invention includes one or more cylindrical resin fin members having a plurality of fins protruding from the inner peripheral surface of the substrate and arranged in series in the metal tube. When this resin material fin member is installed inside the metal tube, the resin material fin member is inserted and arranged inside the metal tube, and the metal tube is extended, so that the metal tube and the resin material fin member adhere to each other. Alternatively, a resin fin member may be bonded and fixed to the inner peripheral surface of the metal tube with an adhesive. Further, the resin fin member may be formed to have substantially the same length as the metal tube, and only one fin member may be provided in the metal tube, or a plurality of resin fin members shorter than the metal tube may be provided. The pipes may be arranged in series inside the metal pipe without any gaps or at intervals.

  Further, by forming the fin member from a resin material, it is possible to obtain a heat transfer tube which is inexpensive and lightweight and has excellent corrosion resistance to a fluid flowing inside. Furthermore, by utilizing the easy processability of the resin material, it is possible to form a fin member provided with more fins in a more complicated shape, and it is possible to increase the heat transfer area of the heat transfer tube. Due to the increase in the heat transfer area, even if the fin member is made of a resin material, it is possible to obtain heat conductivity equal to or higher than that of the fin made of a metal material, and it is possible to obtain a heat transfer tube having excellent heat exchange performance. In addition, by projecting a plurality of fins, a spiral turbulent flow is generated in the fluid flowing in the heat transfer tube, and heat exchange between the fluid and the heat exchange medium through the heat transfer tube is caused by separation of the boundary layer. Can be promoted.

  In addition, the use of lightweight and inexpensive heat transfer tubes with excellent heat exchange performance can improve the heat exchange performance of EGR gas cooling devices and other multi-tube heat exchangers, and reduce the weight of these devices. And miniaturization is also possible. Therefore, it can be easily installed in a narrow place, and the degree of freedom of the layout of the multi-tube heat exchanger is increased. In addition, since the resin-containing fin member is provided with excellent corrosion resistance, the corrosion resistance to condensate such as water vapor in EGR gas, unburned gas, sulfuric acid, and hydrocarbons is increased, and a multi-tube type is provided. The durability of the heat exchanger can be improved. In addition, the soot contained in the EGR gas and the like hardly adheres to the inner peripheral surface made of the resin material of the heat transfer tube, so that a decrease in heat conductivity due to the soot can be suppressed, and the excellent heat exchange performance is improved. Be sustainable.

  In addition, the resin fin member can be formed by integrally projecting a plurality of fins on the inner peripheral surface of a cylindrical substrate having no seams in the circumferential direction. The work of arranging the members on the metal pipe can be easily performed in a small number of steps.

  Further, when a plurality of fins are to be integrally protruded when injection molding a cylindrical substrate as described above, the shape and the number of cores used are limited, and the shape and the number of fins are inevitably reduced. May be limited. Therefore, the resin-made fin member is formed by integrally projecting a plurality of fins on one surface of a band-shaped substrate, then rolling the substrate into a cylindrical shape with the one surface on which the fins are provided inside, and contacting both edges of the substrate with each other. If a cylindrical resin fin member is formed by contact, a more complicated fin can be provided on the substrate to further increase the heat transfer area of the resin fin member. If the heat transfer tube is formed by mounting the cylindrical resin fin member in a metal tube, a product having excellent heat exchange performance can be obtained.

  Further, the fin may have any shape, but if it is a pin-like fin and / or a plate-like fin, the heat transfer area can be increased, and the heat dissipation and heat absorption can be increased. In the case of a plate-like fin, the plate-like fin may have a flat surface having a smooth surface, or may have a side surface having a concavo-convex surface such as a saw-like shape or a waveform, and a plate-like fin having a larger surface area can be obtained. . In the case of a pin-shaped fin, by using a resin material, it is possible to make the pin-shaped fin thinner and longer than a metal product, and it is possible to improve heat radiation and heat absorption. .

  In addition, the plate-shaped fin is provided with a turbulent flow means including any one or a plurality of protrusions, through holes, irregularities, pins, and ridges, thereby further increasing the heat transfer area of the inner peripheral surface of the heat transfer tube. Turbulence of the fluid flowing inside the heat tube is further promoted, and the heat exchange efficiency between the fluid and the heat exchange medium via the heat transfer tube can be increased by separating the boundary layer. Further, even with such a complicated shape, the resin material can be easily formed.

  The pin-shaped fins and / or the pin-shaped turbulence generating means can increase the heat transfer area of the pin-shaped fins if the cross-sectional shape is circular, elliptical, polygonal, star-shaped, or gear-shaped. Thus, the heat exchange efficiency can be improved. In addition, a circular shape, an elliptical shape, and the like can be formed of a metal material, but by using a resin material, it can be formed to be a finer and longer shape than a metal material product, or a polygon, a star, or Even a complicated shape such as a gear shape can be easily formed, and the heat transfer area of the resin fin member can be further increased.

  Also, if the resin material forming the resin material fin member contains carbon nanofibers, the heat conductivity of the resin material heat transfer surface is further increased, and heat exchange between fluids flowing inside and outside the heat transfer tube is achieved. The performance can be further improved. In addition, when the carbon nanofiber is contained in a content of more than 5 wt% and less than 30 wt%, the best thermal conductivity can be obtained. If the content of the carbon nanofibers is 5 wt% or less, the effect of improving the heat transfer effect is poor, and it is difficult to include 30 wt% or more in the resin material. No big difference.

  The term "carbon nanofiber" as used in the present specification indicates a general term including carbon nanotubes, carbon nanohorns, and other nano-unit carbon fibers in the field of nanotechnology. Further, carbon nanotubes, carbon nanohorns, and others may be mixed and contained in the resin material, or may be contained alone. When the carbon nanotube is contained in the resin material, the carbon nanotube may be a single layer or a multi-layer. Further, the aspect ratio of the carbon nanotube does not matter. Further, the thickness, length, and the like of the carbon nanotube are not limited.

  In addition, when a resin material having a black body radiation effect is used in black, the heat conductivity of the resin material fin member is increased, and the heat exchange performance between fluids flowing inside and outside the heat transfer tube can be improved. The resin material may contain particles and / or fibers made of a metal material such as copper, aluminum, and stainless steel having high thermal conductivity, a carbon material, or a glass material, or a powder of the metal material may be formed on the surface of the resin material. The heat exchange performance can be improved by applying a coating material or the like or plating or depositing a metal material. Further, if the metal material, carbon material or glass material particles and fibers, and / or carbon nanofibers are contained in a resin material having a black body radiation effect in black, the heat exchange performance is further improved. Becomes possible.

  Hereinafter, an embodiment in which the heat transfer tube of the present invention is used for an EGR gas cooling device for a vehicle will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a heat transfer tube according to a first embodiment in which a plurality of cylindrical resin fin members having a plurality of pin-shaped fins protruded from a substrate are arranged in series in a metal tube. FIG. FIG. 4 is a perspective view of a band-shaped substrate in which a plurality of pin-shaped fins are provided on one surface, before a material fin member is formed into a cylindrical shape. FIG. 3 is a perspective view of a band-shaped substrate according to the second embodiment, in which a plurality of plate-shaped fins provided with turbulence generating means formed of through holes are provided. FIG. 4 is a perspective view of a strip-shaped substrate according to a third embodiment, in which a plurality of plate-shaped fins provided with pin-shaped turbulence generating means are protruded. FIG. 5 is a perspective view of a band-shaped substrate according to a fourth embodiment, in which a plurality of plate-shaped fins having a corrugated side shape are provided.

  FIG. 6 is a perspective view of a fin member made of a resin material according to a fifth embodiment, in which a plurality of projections are protruded on both side surfaces of a plate-like fin in a direction intersecting a cylindrical axis to form a turbulent flow means. FIG. 7 is a perspective view of a heat transfer tube in which a resin material fin member of Example 6 is provided. The resin material fin member is parallel to the cylindrical axis on the inner peripheral surface of a cylindrical substrate having no circumferential joint. A plate-like fin is provided which protrudes a plurality of ridges and serves as a turbulent flow means. FIG. 8 is a plan view of FIG. FIG. 9 is a schematic diagram of an EGR gas cooling device using the heat transfer tube according to the first embodiment. FIG. 10 shows a comparison of the heat exchange performance of a pipe having an outer surface coated with a PA resin, a pipe having an outer surface coated with a PA resin and a PP resin, and a pipe formed of only a steel pipe. FIG. 11 is a conceptual diagram of the experiment, and FIG. 11 is a graph of the result of the comparative experiment.

  First, in carrying out the present invention, a comparative experiment was conducted on the heat exchange performance of a heat transfer surface having a resin surface material. As shown in FIG. 10, in this experimental apparatus, a pipe (32) having a diameter of 8 mm and a length of 1900 mm was arranged in a wind tunnel (31), and a hot water provided with a thermometer (33) was provided in the pipe (32). A tank (34), a pump (35), and a flow meter (36) are connected, and hot water at a temperature of about 60 ° C. is flowed through the pipe (32) at a flow rate of 0.9 L / m. Cooling air is blown into the wind tunnel portion (31) by the fan (37), and the hot water is cooled by the cooling air through the pipe (32).

  Then, the heat exchange performance between the cooling air and the hot water in the pipe (32) is measured by measuring the inlet and outlet temperatures of the hot water and calculating the temperature difference. The relationship between the temperature difference and the wind speed is shown in Table 1 below and the graph of FIG. In the experiment, pipes (32) (hereinafter referred to as PA coated pipes) were prepared by subjecting the outer surface of a steel pipe having a wall thickness of 0.7 mm to zinc plating and chromate treatment of 13 μm and further coating with a PA resin having a wall thickness of 50 μm. A pipe (32) (13 mm) which is formed by applying 13 μm zinc plating and chromate treatment to the outer surface of a steel pipe having a thickness of 0.7 mm and further coating it with a PA resin having a thickness of 50 μm and a PP resin having a thickness of 1.0 mm. It was used. Further, as a comparative experiment, the heat exchange performance of a pipe (32) formed only of a steel pipe was also measured. This steel pipe had a wall thickness of 0.7 mm and had no outer surface subjected to any surface treatment.

  In Table 1 below, the reason why the wind speed (m / s) does not completely match between the PA-coated pipe, the PA + PP-coated pipe, and the pipe made of only the steel pipe is that it is technically difficult to obtain a completely matched wind velocity. Because it is. Therefore, an approximate wind speed is generated, and the wind speed shown in Table 1 is obtained by measuring the wind speed.

  According to the above-mentioned experiment, the heat exchange performance of the PA-coated pipe and the PA + PP-coated pipe is only deteriorated by about 4 to 15% at the wind speed of about 6 m / s. Indicated. From this experimental result, it was found that if the surface area of the heat transfer surface made of resin material was increased by 15% or more, heat exchange performance equal to or higher than that of the heat transfer surface made of metal material could be obtained. As a means for increasing the surface area, a heat transfer tube having a resin-made fin member as in Examples 1 to 6 shown in FIGS. 1 to 8 was formed.

  In carrying out the present invention, by using a resin material or the like as shown in Table 2 below, a heat transfer tube having not only excellent heat exchange performance but also excellent corrosion resistance and heat resistance can be obtained. Further, if heat resistance is not so required, more kinds of resin materials can be used. In addition, by using this heat transfer tube, the heat exchange performance, corrosion resistance and durability of the EGR gas cooling device and other multi-tube heat exchangers and the heat resistance of the resin materials shown in Table 2 can be improved. Can be.

  The first embodiment shown in FIGS. 1, 2 and 9 using the above resin material will be described in detail. (1) is a heat transfer tube, and a metal tube (2) is provided inside a stainless steel tube or another metal tube (2). A plurality of cylindrical resin fin members (3) shorter than 2) are arranged in series. The manufacturing process of the heat transfer tube (1) will be described. First, as shown in FIG. 2, the fin member (3) has the length a in the width direction and the circumferential length of the inner circumferential surface of the metal tube (2). A rectangular smooth substrate (4) having substantially the same length and a length b in the longitudinal direction shorter than the length in the axial direction of the metal tube (2) is formed, and a plurality of substrates are formed on one surface of the substrate (4). The pin-shaped fins (5) are integrally protruded. By molding using a resin material, it is possible to easily form a substrate (4) having such a number of pin-shaped fins (5) protruding innumerably. It is also possible to compact the long pin-shaped fins (5).

  Next, the band-shaped substrate (4) provided with the pin-shaped fins (5) as described above is rounded into a cylindrical shape with one surface provided with the pin-shaped fins (5) inside, and both end edges of the substrate (4) are formed. (6) is brought into contact with each other to form a cylindrical fin member (3). Then, as shown in FIG. 1, a plurality of the cylindrical fin members (3) are inserted and arranged in series in the metal tube (2). In this arrangement, the cylindrical fin members (3) adjoining in series are in close contact with each other so that no gap is formed. Thereafter, the metal tube (2) is expanded to bring the metal tube (2) into close contact with the resin fin member (3) to obtain the heat transfer tube (1). Also, the metal pipe (2) and the resin material fin member (3) do not adhere to each other by extending the metal pipe (2), but are bonded to the inner peripheral surface of the metal pipe (2) with an adhesive. The outer peripheral surfaces of the material fin members (3) may be adhered to each other by bonding.

  In the heat transfer tube (1) in which the fin member (3) made of resin material as described above is installed, heat transfer on the inner surface of the fin member (3) made of resin material is achieved by forming an infinite number of fine pin-shaped fins (5). The area can be increased. Therefore, the heat transfer tube (1) having heat conductivity equal to or higher than that of the conventional heat transfer tube in which the metal fin member is installed can be obtained, and the heat transfer tube (1) can be reduced in weight and cost. Becomes possible.

  As shown in FIG. 9, the EGR gas cooling device (10) using the heat transfer tube (1) as described above is provided with a tube sheet (12) near both ends of a cylindrical body tube (11) so that the inside can be hermetically sealed. ) Are connected as a pair, and an airtight space partitioned by the tube sheet (12) serves as a heat exchange unit (13) for exchanging heat between the EGR gas and the refrigerant liquid. A plurality of the heat transfer tubes (1) are connected and arranged between the pair of tube sheets (12) through the tube sheet (12). A bonnet (16) provided with an inlet (14) and an outlet (15) for EGR gas is connected to both ends of the body tube (11).

  Further, the body pipe (11) is provided with an introduction path (17) for supplying the refrigerant liquid to the heat exchange section (13) and an outlet path (18) for discharging the refrigerant liquid after the heat exchange, and the heat exchange section (13). The refrigerant liquid is allowed to flow in the parentheses. Further, the heat exchange section (13) has a plurality of support plates (20) joined and arranged therein, and a heat transfer tube (1) is inserted through an insertion hole (21) provided in the support plate (20). In addition to stably supporting the heat transfer tube (1) as a baffle plate, the flow of the refrigerant liquid flowing in the heat exchange section (13) is meandering, and the relative speed to the outer surface of the heat transfer tube (1) is increased. .

  In the above EGR gas cooling device (10), heat exchange between the EGR gas and the refrigerant liquid is efficiently performed through the heat transfer surface of the heat transfer tube (1) having excellent heat conductivity, and the cooling effect is enhanced. Can do things. In addition, this excellent cooling effect allows the size of the EGR gas cooling device (10) to be reduced, and the use of the light and inexpensive heat transfer tube (1) of the present invention allows the EGR gas cooling device (10) to be used. Weight reduction and cost reduction are also possible. In addition, the small and lightweight EGR gas cooling device (10) can be installed in a narrow place, thereby increasing the degree of freedom in layout.

  In addition, since the resin material fin member (3) is provided inside the heat transfer tube (1) through which the EGR gas flows, the heat transfer tube (1) is capable of removing condensate such as water vapor, unburned gas, sulfuric acid, and hydrocarbons in the EGR gas. By using a resin material as shown in Table 2, it is excellent in heat resistance to high-temperature EGR gas, and the durability of the EGR gas cooling device (10) can be improved. In addition, the fact that the inner peripheral surface is made of a resin material prevents soot contained in the EGR gas from adhering and accumulating on the heat transfer tube (1), thereby suppressing a decrease in the thermal conductivity of the heat transfer tube (1). As a result, efficient heat exchange can be maintained.

  Further, the fin member (3) provided in the heat transfer tube (1) of the first embodiment has a pin-shaped fin (5) protruding therefrom. In another different second embodiment, as shown in FIG. A plurality of plate-like fins (7) are provided on one surface of the plate-like substrate (4) in parallel with the cylindrical axis and are integrally provided with the substrate (4) at regular intervals. The plate-like fin (7) is provided with a turbulent flow means (8) by randomly opening through holes.

  Further, in the third embodiment shown in FIG. 4, as in the second embodiment, a plurality of flat plate-like fins (7) are integrally protruded from one surface of the substrate (4) at regular intervals. In the third embodiment, a pin-shaped turbulent flow means (8) is protruded from the plate-like fin (7). Even in the case of the plate-like fin (7) provided with the turbulent flow means (8) as in the second and third embodiments, the use of a resin material enables easy molding, and the resin-made fin member ( By increasing the heat transfer area of 3), the heat exchange performance of the heat transfer tube (1) can be improved.

  In the second and third embodiments, the flat plate-like fins (7) are protruded from the substrate (4). However, in another different fourth embodiment, as shown in FIG. The plate-like fins (7) protrude. In the plate-like fin (7) having such a waveform, the heat transfer area can be increased by the unevenness formed on the surface, and the unevenness acts as the turbulent flow means (8), and the turbulent flow of the EGR gas is increased. Can be increased.

  In Embodiment 5 shown in FIG. 6, a plurality of plate-like fins (7) are protruded from a plate-like substrate (4), and a plurality of plate-like fins (7) are provided on both side surfaces in a direction intersecting the cylindrical axis. And a turbulent flow means (8). Even with such a complicated shape, if a resin material is used, easy molding can be performed, and a heat transfer area can be increased and a fluid can be made turbulent.

  In the first to fifth embodiments, the pin-shaped fin (5) or the plate-shaped fin (7) is formed by projecting the plate-shaped substrate (4), and then rounded into a cylindrical shape to form the resin-made fin member (3). In Example 6 shown in FIGS. 7 and 8, the substrate (4) is formed into a cylindrical shape in advance to obtain a cylindrical fin member (3) having no seams in the circumferential direction. ing. In forming the fin member (3), a plurality of plate-like fins (7) are integrally formed on the inner peripheral surface of the substrate (4) in parallel with the cylindrical axis. Further, a plurality of ridges parallel to the cylindrical axis of the cylindrical fin member (3) are formed on both side surfaces of the plate-like fin (7) to serve as a turbulent flow means (8). The turbulence generating means (8) formed by the ridges parallel to the cylindrical axis direction of the cylindrical fin member (3) is formed by extrusion molding or by inserting a core into a cylindrical mold. Alternatively, the core can be easily formed by injecting the resin material into the mold and then solidifying the core in the axial direction.

  Further, in each of the above embodiments, the substrate (4) and the pin-shaped fins (5) or the plate-shaped fins (7) are formed integrally at the time of molding. The pin-shaped fin (5) or the plate-shaped fin (7) is formed separately, and the substrate (4) and the pin-shaped fin (5) or the plate-shaped fin (7) are welded with a resin material or bonded by an adhesive or the like. May be integrated to form a resin material fin member (3). The resin material forming the fin member (3) made of a resin material includes powder of a metal material such as copper, aluminum, and stainless steel having a high thermal conductivity, powder and fiber of a glass material, powder and fiber of a carbon material, and the like. May be mixed, the surface may be coated with a paint mixed with a metal material powder or the like, or the metal material may be plated or vapor-deposited.

  Further, even when a black resin material having a black body radiation effect is used, the heat conductivity of the heat transfer surface of the fin member (3) made of the resin material is increased, and the performance of cooling the EGR gas can be improved. Further, the resin material having a black body radiation effect in black may contain the above-mentioned metal material, carbon material, glass material particles and fibers, and / or carbon nanofibers described later, and further improve the cooling effect. A further improvement is possible.

  In addition, by including carbon nanofibers in the resin material, it is possible to further improve the thermal conductivity of the heat transfer surface of the resin material fin member (3), thereby effectively improving the cooling performance to the EGR gas. It is possible to do. When carbon nanofibers are contained in a resin material, the best heat transfer effect can be obtained by containing carbon nanofibers in a content of more than 5 wt% and less than 30 wt%.

FIG. 1 is a perspective view showing a heat transfer tube according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a manufacturing process of a fin member housed in the heat transfer tube of FIG. 1. FIG. 10 is a perspective view of a resin fin member according to the second embodiment. FIG. 9 is a perspective view of a resin fin member according to a third embodiment. FIG. 13 is a perspective view of a resin fin member according to a fourth embodiment. FIG. 17 is a perspective view of a resin fin member according to a fifth embodiment. FIG. 17 is a perspective view of a heat transfer tube in which a resin fin member according to a sixth embodiment is provided. The top view of FIG. The conceptual diagram of the EGR gas cooling device using the heat transfer tube. The conceptual diagram of a heat exchange performance experiment. Heat exchange performance graph.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Heat transfer tube 2 Metal tube 3 Fin member 4 Substrate 5 Pin-shaped fin (fin of the present invention)
6 Side edges 7 Plate fin (fin of the present invention)
8 Turbulence measures

Claims (9)

A heat transfer tube provided with a resin material fin member, wherein one or a plurality of cylindrical resin material fin members having a plurality of fins protruding from an inner peripheral surface of a substrate are disposed in series in a metal tube. The resin-made fin member according to claim 1, wherein a plurality of fins are integrally provided on an inner peripheral surface of a cylindrical substrate having no joint in the circumferential direction. Heat transfer tubes. The resin-made fin member is formed by integrally projecting a plurality of fins on one surface of a band-shaped substrate, forming the substrate into a cylindrical shape with the one surface on which the fins are provided inside, and bringing both ends of the substrate into contact with each other. 2. The heat transfer tube according to claim 1, wherein the heat transfer tube has a cylindrical fin member made of a resin material. The heat transfer tube according to claim 1, 2 or 3, wherein the fin is a pin-shaped fin and / or a plate-shaped fin. 5. The heat transfer tube according to claim 4, wherein the plate-like fin is provided with a turbulent flow means comprising any one or a plurality of protrusions, through holes, irregularities, pins, and ridges. 6. The resin-made fin member according to claim 4, wherein the pin-shaped fins and / or the pin-shaped turbulence generating means have a cross-sectional shape of a circle, an ellipse, a polygon, a star, or a gear. Heat transfer tube with interior. The resin-made fin member contains particles and / or fibers having higher thermal conductivity than the resin material forming the resin-made fin member. Or a heat transfer tube containing the resin material fin member according to item 6. The resin-made fin member according to claim 1, 2, 3, 4, 5, 6, or 7, wherein a carbon nanofiber is contained in a resin material forming the resin-made fin member. Heat transfer tube with fin members inside. 9. The heat transfer tube according to claim 8, wherein the carbon nanofiber is contained in a content of more than 5 wt% and less than 30 wt%.

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