Internal fin pressure tube forming tool and method for solid-liquid phase change temperature difference heat exchanger

Abstract

The present invention discloses a forming tool and method for an inner fin pressure tube of a solid-liquid phase change temperature difference heat exchanger. The forming tool includes a circumferential limit flange, an axial limit flange, an expansion flange, a limit pull rod, and an expansion pull rod. The circumferential limit flange is movably connected to a plurality of inner fins and is respectively arranged at the upper, middle, and lower parts of the inner fins. The expansion flange is movably connected to the inner fins and is respectively located above the upper circumferential limit flange and below the lower circumferential limit flange; the limit pull rod is connected to the circumferential limit flange and the expansion flange; the expansion pull rod is connected to the expansion flange; the axial limit flange is respectively used to be fixedly installed at the port of the pressure tube through the limit pull rod. Under the tightening action of the limit pull rod, the axial limit flange is respectively fitted with the two ports of the pressure tube to realize the axial limitation of each inner fin in the inner wall of the pressure tube. The present invention avoids the high process requirements of the titanium alloy welding method and the loss of the pressure bearing capacity of the pressure tube.

Description

Technical Field

[0001] The present invention belongs to the technical field of ocean temperature difference energy capture and conversion, and in particular relates to an inner fin pressure-bearing tube forming tool and method for a solid-liquid phase change temperature difference energy heat exchanger. Background Art

[0002] In recent years, with the development of solid-liquid phase change material technology, marine temperature difference heat exchangers based on the thermal expansion and contraction properties of solid-liquid phase change materials have emerged. Compared with traditional marine temperature difference heat exchangers using gas-liquid phase change media, solid-liquid phase change temperature difference heat exchangers have the advantages of compact structure and miniaturization. They are suitable for installation on small and medium-sized underwater mobile platforms and provide environmental energy supplements to the platforms, realizing buoyancy drive and power supply. However, the seawater temperature gradient is small (usually no more than 35°C), and the thermal conductivity of applicable solid-liquid phase change materials (paraffin materials) is low. Therefore, the heat transfer rate of solid-liquid phase change temperature difference heat exchangers needs to be improved urgently.

[0003] Adding internal fins to the inner wall of the heat exchanger's pressure-bearing tubes is a solution for enhancing heat transfer, expanding the heat transfer area while maintaining the heat exchanger's smooth appearance. Due to the pressure-bearing tubes' need to withstand external seawater pressure (on the order of kilometers) and internal melt expansion pressure (maximum 25MPa), and to withstand long-term seawater corrosion, they are made of TC4 titanium alloy, which requires high welding process requirements, have an inner diameter of 60mm, and an aspect ratio of 10:1. This makes the forming process of attaching the additional internal fins to the pressure-bearing tubes challenging. Traditional internal fin tube processing techniques such as welding, casting, and cold drawing are unable to meet the pressure-bearing tube material, dimensional constraints, and pressure-bearing capacity requirements. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a forming tool and method for an inner finned pressure tube of a solid-liquid phase change temperature difference energy heat exchanger. The forming tool and method proposed in the present invention can achieve the fixed connection of the inner fin to the inner wall of the pressure tube while maintaining the original size, material, and pressure bearing capacity of the pressure tube, thereby increasing the heat exchange area and thermal conductivity of the solid-liquid phase change temperature difference energy heat exchanger.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A forming tool for an inner fin pressure-bearing tube of a solid-liquid phase-change temperature difference heat exchanger, used for forming the inner fin and the pressure-bearing tube by fixed connection, comprising a circumferential limit flange, an axial limit flange, an expansion flange, a limit rod, and an expansion rod; the circumferential limit flange and the axial limit flange are both annular structures, and the outer side of the annular ring of the circumferential limit flange is uniformly distributed with a plurality of first grooves; a first limit rod hole is provided between the first grooves; a second limit rod hole is provided on the annular ring of the axial limit flange; the expansion flange is a disc-shaped structure, and four fan-shaped holes are evenly provided on the expansion flange; a second groove is provided on the outer side of the expansion flange, a third limit rod hole is provided between the second grooves, and an expansion rod hole is provided in the middle of the expansion flange; the circumferential limit flange is provided ... The positioning flange is movably connected to several inner fins through the first groove and is respectively arranged at the upper, middle and lower parts of the inner fins. The expansion flange is movably connected to the inner fins through the second groove and is respectively located above the upper circumferential limit flange and below the lower circumferential limit flange; the limiting rod is connected to the circumferential limit flange and the expansion flange through the first limiting rod hole and the third limiting rod hole respectively; the expansion rod is connected to the expansion flange through the expansion rod hole; the axial limiting flanges are respectively used to be fixedly installed at the ports of the pressure pipe through the limiting rods. Under the tightening action of the limiting rods, the axial limiting flanges are respectively fitted with the two ports of the pressure pipe to realize the axial limitation of each inner fin in the inner wall of the pressure pipe.

[0007] Furthermore, the number of the first groove, the first limiting rod hole, the second limiting rod hole, the second groove, and the third limiting rod hole are all 12.

[0008] Furthermore, the pressure pipe is made of titanium alloy TC4 material, has an inner diameter of 60 mm, and an aspect ratio of 10:1, and can withstand the external pressure of the shell of 1000 m seawater and the internal pressure of the shell of 25 MPa.

[0009] Furthermore, the inner fin is a rectangular structure made of aluminum alloy 6061-T6 material, with a length of 600 mm and a thickness of 0.8 mm.

[0010] Furthermore, the upper and lower ends of the inner fin are provided with inclined surfaces, and the side surfaces of the inner fin are used to be fixed to the pressure tube; the gap range between the inner fin and the first groove and the second groove is ±0.02mm, and the inner fin can move in the first groove and the second groove; the expansion rod passes through the expansion rod hole and penetrates the pressure tube.

[0011] Furthermore, an angle of 15° to 25° exists between the groove slope of the second groove and the rotation axis of the expansion flange.

[0012] The present invention also provides a forming method for an inner fin pressure-bearing tube, based on an inner fin pressure-bearing tube forming tool, comprising:

[0013] S1. Place the forming tool in the pressure tube and secure the axial limit flanges to the ends of the pressure tube via limit rods. With the tightening action of the limit rods, the axial limit flanges engage the two ends of the pressure tube, achieving axial limit of each inner fin on the inner wall of the pressure tube.

[0014] S2. Tighten both ends of the expansion rod, causing the two expansion flanges to move toward each other from the opposite ends of the pressure tube. The grooved surfaces then contact the inclined surfaces of the inner fins. As the tightening force increases, the grooved surfaces force the sides of the inner fins into contact with the inner wall of the pressure tube.

[0015] S3. After the inner fins are pre-installed in the pressure tube, the pressure tube with the inner fins and the forming tooling is placed on a movable bonding table; the movable bonding table includes a phase indexing head and a linear guide slide;

[0016] During the bonding process, the phase indexing head drives the pressure tube in circumferential rotation, while the linear guide slide drives the fully automatic dispensing machine in continuous and smooth axial movement. A dispensing needle is introduced from the fully automatic dispensing machine. The needle extends from a side port into the pressure tube through the central fan-shaped hole of the circumferential limit flange and the expansion flange, where it contacts the base of the inner fin where the inner wall of the tube meets.

[0017] S5. As the thermally conductive silicone is squeezed out of the needle tip, the linear guide slide automatically moves horizontally at a constant speed, applying glue to the base of the inner fin and the inner wall of the pressure tube at half the length of the pressure tube. The phase indexing head rotates the pressure tube through a set angle, and the needle is inserted into the tube again. This operation is repeated until the phase indexing head completes a 360° rotation.

[0018] S6. Turn the port of the pressure tube around, insert the needle into the port on the other side of the tube, and perform the gluing operation again; until all the inner fins are bonded to the pressure tube and the thermally conductive silicone is cured, loosen the nuts on both ends of the limit rod and the expansion rod, and withdraw the circumferential limit flange, axial limit flange, expansion flange, limit rod, and expansion rod of the forming tooling from the inside of the pressure tube; thus, the inner fins are fixedly connected to the pressure tube in a circumferentially uniform manner.

[0019] Furthermore, the inner diameter of the needle is 0.3 mm, the outer diameter is 0.6 mm, and the length is 500 mm.

[0020] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0021] 1. The present invention adopts thermal conductive silicone bonding instead of high temperature welding, avoiding the high process requirements of titanium alloy welding and the loss of pressure bearing capacity of the pressure pipe.

[0022] 2. The tooling of the present invention realizes the expansion and tight fit between the inner fins and the inner wall of the pressure tube, and prevents the inner fins from excessive bending inside the pressure tube before being fixed. The inner fins are arranged circumferentially with regular and uniform phases.

[0023] 3. The inner fin pressure-bearing tube formed by the present invention increases the contact heat exchange area between the metal tube wall and the phase change material of the solid-liquid phase change temperature difference heat exchanger, which can improve the heat exchange capacity of the heat exchange tube and accelerate the phase change process.

[0024] 4. The inner fins are arranged circumferentially with regular and even phase distribution and point to the center of the circle. The inner fins do not block the radial transfer of heat flow. This arrangement ensures smooth radial heat transfer path between seawater, metal tube wall and phase change material within the cross section of the heat exchanger.

[0025] 5. The tooling of the present invention is simple, low-cost, and easy to manufacture, and can be disassembled and withdrawn after the inner fins and the pressure-bearing tube are bonded and fixed.

[0026] 6 The circumferential limiting flange of the present invention enables the inner fins to be arranged circumferentially at a preset phase and placed into the inner wall of the pressure tube, thereby preventing the deviation of the circumferential arrangement position of the inner fins.

[0027] 7. This invention utilizes a phase indexing head to precisely rotate the pressure tube in the circumferential direction during the injection process, and a linear guideway to precisely move the needle in the axial direction, ensuring accurate injection positioning and a continuous, smooth injection process. Compared to traditional processes, this invention's tooling is simpler, less expensive, and easier to manufacture. Once the inner fins are bonded to the pressure tube, they can be removed.

[0028] 8. The present invention achieves the fixed connection of the inner fins to the inner wall of the pressure tube while maintaining the original size, material and pressure bearing capacity of the pressure tube, so as to increase the heat exchange area and heat conduction capacity of the solid-liquid phase change temperature difference heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1a This is a structural diagram of the inner fin and the forming tool being installed into the pressure pipe; Figure 1b Schematic diagram of the explosion structure of the inner fin pressure tube when only one inner fin is installed (the pressure tube is half-cut).

[0030] Figure 2 It is a structural diagram of the forming tooling;

[0031] Figure 3 This is the layout diagram of the inner fins in the forming tooling;

[0032] Figure 4 It is a cross-sectional view of the inner fin and the forming tooling;

[0033] Figure 5 Schematic diagram of the glue injection process;

[0034] Figure 6a and Figure 6b They are respectively a three-dimensional view and a top view of the inner fin and the pressure tube after being fixedly connected and formed;

[0035] Figure 7 is a cross-sectional view of the circumferential limit flange;

[0036] Figure 8 It is a cross-sectional view of the axial limiting flange;

[0037] Figure 9 It is a cross-sectional view of the expansion flange;

[0038] Figure 10 It is a cross-sectional view of the expansion flange;

[0039] Figure 11 This is the structural diagram of the inner fin. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] like Figure 1a and Figure 1b As shown, this embodiment provides a forming tool for the inner finned pressure tube of a solid-liquid phase-change temperature differential heat exchanger, used to securely connect the inner fin 2 to the pressure tube 1. The tool comprises a circumferential limit flange 3, an axial limit flange 4, an expansion flange 5, a limit rod 6, and an expansion rod 7. The outer edge of the circular ring of the circumferential limit flange 3 is uniformly distributed with 12 grooves 31; limit rod holes 32 are provided between the grooves 31; the circular ring of the axial limit flange 4 is provided with a limit rod hole 41; the expansion flange 5 is a disc-shaped structure, with an expansion rod hole 52 located at the center of its axis. The expansion rod 7 passes through the expansion rod hole 52 and exits the pressure tube 1.

[0042] The circumferential limit flange 3 is movably connected to the 12 inner fins 2 through the groove 31 and is respectively arranged at the upper, middle and lower parts of the inner fin 2. The expansion flange 5 is movably connected to the inner fin 2 through the groove 51 and is respectively located above the upper circumferential limit flange 3 and below the lower circumferential limit flange 3; the limit rod 6 is connected to the circumferential limit flange 3 and the expansion flange 5 through the limit rod hole 32 and the limit rod hole 53 respectively; the expansion rod 7 is connected to the expansion flange 5 through the expansion rod hole 52.

[0043] Specifically, in this embodiment, the pressure tube 1 is made of titanium alloy TC4, with an inner diameter of 60 mm and an aspect ratio of 10:1. It can withstand an external shell pressure of 1000 m of seawater and an internal shell pressure of 25 MPa. The inner fins 2 are slender rectangular metal heat-conducting fins made of aluminum alloy 6061-T6, 600 mm long and 0.8 mm thick.

[0044] See Figure 7 The circumferential limit flange 3 is an annular structure with 12 grooves 31 evenly distributed along the outer edge of the annular ring. The grooves 31 point to the rotation axis of the circumferential limit flange 3. Limit rod holes 32 are set between the grooves 31. The inner fins 2 can be placed in the grooves 31. There is a slight gap (tolerance range ±0.02mm) between the inner fins 2 and the grooves 31, allowing the inner fins 2 to move within the grooves 31. The middle part of the circumferential limit flange 3 is a hollow structure to facilitate the glue injection and bonding operation between the pressure tube 1 and the inner fins 2.

[0045] See Figure 2 In the forming tooling, three circumferential limit flanges 3 are axially arranged along the inner wall of the pressure tube 1. The limit rod 6 extends through the limit rod hole 32 using an interference fit. The three circumferential limit flanges 3 are located at the two ends and the middle section of the pressure tube 1. These three circumferential limit flanges 3 support and maintain the inner fin 2 in its basic circumferential phase position within the inner wall of the pressure tube 1. They also help align the 600 mm long inner fin along the axis of the pressure tube 1.

[0046] See Figure 8 The axial limit flange 4 is annular in structure. Two axial limit flanges 4 are installed in the forming tooling, one at each end of the pressure tube 1. Each axial limit flange 4 has 12 limit rod holes 41, through which 12 limit rods 6 extend. These holes 41 extend through the pressure tube 1. With the tightening action of the limit rods 6, the two axial limit flanges 4 mate with the outwardly flared stepped surfaces at the ends of the pressure tube 1, respectively, effectively limiting the axial position of each inner fin 2 within the inner wall of the pressure tube 1.

[0047] See Figure 3 、 4 9. The expansion flange 5 is disc-shaped and has twelve grooves 51 evenly distributed around its axis of rotation, with the grooves 51 pointing toward the axis. Four fan-shaped holes 54 are evenly spaced outside the expansion rod hole 52 in the center of the expansion flange 5 to facilitate adhesive injection and bonding between the pressure-bearing tube 1 and the inner fin 2. Grooves 51 corresponding to grooves 31 are located on the outside of the expansion flange 5, with limit rod holes 53 located between them.

[0048] like Figure 3 、 4 As shown in Figures 10 and 11, the groove bevel 511 of the expansion flange groove 51 forms a 15° angle with the axis of rotation of the expansion flange 5. Two expansion flanges 5 are installed in the forming tool, one at each end of the pressure tube 1. A slight gap (with a tolerance of ±0.02mm) exists between the inner fin 2 and the groove 51, allowing the inner fin 2 to move within the groove 51 before tightening.

[0049] See Figure 11The upper and lower ends of the inner fin 2 are both provided with inclined surfaces 21, and the side surfaces 22 are used for fixing with the pressure pipe 1.

[0050] This embodiment further provides a forming method for an inner finned pressure-bearing tube, based on the inner finned pressure-bearing tube forming tool, comprising:

[0051] Under the tightening action of the expansion rod 7, the two expansion flanges 5 move toward each other from the two ends of the pressure tube 1, and then the groove slope 511 contacts the slope 21 of the inner fin 2. As the tightening force increases, the groove slope 511 forces the side surface 22 of the inner fin 2 to fit tightly against the inner wall of the pressure tube 1.

[0052] like Figure 5 As shown, after the forming tool completes the expansion and pre-installation of the inner fin 2 in the pressure tube 1, the pressure tube 1, the inner fin 2 and the forming tool assembly are placed on the movable bonding table 8. The movable bonding table 8 includes a phase indexing head 81 and a linear guide slide 82.

[0053] During the bonding process, the phase dividing head 81 drives the pressure-bearing pipe 1 to rotate precisely in the circumferential direction, and the linear guide slide 82 drives the fully automatic dispensing machine 9 to achieve continuous and smooth axial movement.

[0054] A precision dispensing stainless steel needle 10 is introduced from the fully automatic dispensing machine 9. Needle 10 has an inner diameter of 0.3mm, an outer diameter of 0.6mm, and a length of 500mm. Through the hollowed-out structure of the circumferential limit flange 3 and the expansion flange 5, needle 10 extends from one of the ports of the pressure tube 1 into the tube shell. The tip of needle 10 contacts the side 22 where the inner wall of the pressure tube 1 meets the inner fin 2.

[0055] As the thermal conductive silicone 11 is squeezed out from the end of the needle 10, the linear guide slide 82 drives the fully automatic dispensing machine to move horizontally at a constant speed, realizing the gluing and bonding operation between the side surface 22 of the inner fin 2 and the inner wall of the pressure tube 1 in an axial length of 300 mm (50% of the length of the pressure tube).

[0056] The phase dividing head 81 drives the pressure tube 1 to rotate an angle, and the needle 10 is inserted into the pressure tube 1 again. The operation can be repeated to implement gluing and bonding of multiple inner fins with uniform phase distribution.

[0057] After the phase dividing head 81 completes the 360° rotation, the port of the pressure-bearing tube 1 is turned, and the needle 10 is inserted from the other port of the pressure-bearing tube 1 to perform the gluing operation again.

[0058] like Figure 6a and Figure 6bAs shown, after all the inner fins 2 are bonded to the pressure tube 1 and the thermal conductive silicone 11 is cured, the nuts at both ends of the limit rod and the expansion rod are loosened and removed, and the circumferential limit flange 3, axial limit flange 4, expansion flange 5, limit rod 6, and expansion rod 7 of the forming tool are withdrawn from the inner wall of the pressure tube 1, so that the inner fins are fixed to the pressure tube in a circumferentially uniform manner.

[0059] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, those skilled in the art may make various specific modifications based on the teachings of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A forming tool for an inner fin pressure tube of a solid-liquid phase change temperature difference heat exchanger, used for forming an inner fin (2) and a pressure tube (1), characterized in that: The invention comprises a circumferential limiting flange (3), an axial limiting flange (4), an expansion flange (5), a limiting rod (6), and an expansion rod (7); the circumferential limiting flange (3) and the axial limiting flange (4) are both annular structures, and a plurality of first grooves (31) are evenly distributed on the outer side of the annular ring of the circumferential limiting flange (3); a first limiting rod hole (32) is provided between the first grooves (31); a second limiting rod hole (41) is provided on the annular ring of the axial limiting flange (4); the expansion flange (5) is a disc-shaped structure, and four fan-shaped holes (54) are evenly distributed on the expansion flange (5); a second groove (51) is provided on the outer side of the expansion flange (5), a third limiting rod hole (53) is provided between the second grooves (51), and an expansion rod hole (52) is provided in the middle of the expansion flange (5); the circumferential limiting flange (3) is connected to a plurality of inner fins through the first groove (31). (2) are movably connected and respectively arranged at the upper, middle and lower parts of the inner fin (2); the expansion flange (5) is movably connected to the inner fin (2) through the second groove (51) and is respectively located above the upper circumferential limit flange (3) and below the lower circumferential limit flange (3); the limit rod (6) is connected to the circumferential limit flange (3) and the expansion flange (5) through the first limit rod hole (32) and the third limit rod hole (53); the expansion rod (7) is connected to the expansion flange (5) through the expansion rod hole (52); the axial limit flange (4) is respectively used to be fixedly installed at the port of the pressure pipe (1) through the limit rod (6); under the tightening action of the limit rod (6), the axial limit flange (4) is respectively fitted with the two ports of the pressure pipe (1), so as to realize the axial limit of each inner fin (2) in the inner wall of the pressure pipe (1).

2. The inner fin pressure tube forming tool for a solid-liquid phase change temperature difference heat exchanger according to claim 1, characterized in that: The number of the first groove (31), the first limiting rod hole (32), the second limiting rod hole (41), the second groove (51), and the third limiting rod hole (53) is 12.

3. The forming tool for inner fin pressure tube of solid-liquid phase change temperature difference heat exchanger according to claim 1, characterized in that: The pressure-bearing pipe (1) is made of titanium alloy TC4 material, has an inner diameter of 60 mm, and a length-to-diameter ratio of 10:1, and is capable of withstanding an external shell pressure of 1000 m seawater and an internal shell pressure of 25 MPa.

4. The forming tool for inner fin pressure tube of solid-liquid phase change temperature difference heat exchanger according to claim 1, characterized in that: The inner fin (2) is a rectangular structure made of aluminum alloy 6061-T6 material, with a length of 600 mm and a thickness of 0.8 mm.

5. The forming tool for inner fin pressure tube of solid-liquid phase change temperature difference heat exchanger according to claim 1, characterized in that: The upper and lower ends of the inner fin (2) are both provided with inclined surfaces (21), and the side surface (22) of the inner fin (2) is used for fixing with the pressure-bearing pipe (1); the gap between the inner fin (2) and the first groove (31) and the second groove (51) is within a range of ±0.02 mm, and the inner fin (2) can move within the first groove (31) and the second groove (51); the expansion rod (7) passes through the expansion rod hole (52) and penetrates the pressure-bearing pipe (1).

6. The forming tool for inner fin pressure tube of solid-liquid phase change temperature difference heat exchanger according to claim 1 or 5, characterized in that: There is an angle of 15° to 25° between the groove slope (511) of the second groove (51) and the rotation axis of the expansion flange (5).

7. A forming method for an inner finned pressure tube, based on the inner finned pressure tube forming tool for a solid-liquid phase change temperature difference heat exchanger according to any one of claims 1 to 6, characterized in that: include: S1. Place the forming tool in the pressure-bearing pipe (1), and fix the axial limit flanges (4) to the ports of the pressure-bearing pipe (1) through the limit rods (6). Under the tightening action of the limit rods (6), the axial limit flanges (4) are respectively fitted with the two ports of the pressure-bearing pipe (1), thereby realizing the axial limit of each inner fin (2) in the inner wall of the pressure-bearing pipe (1); S2. Tighten the two ends of the expansion rod (7) to move the two expansion flanges (5) toward each other from the two ends of the pressure tube (1). Then, the groove bevel (511) contacts the bevel (21) of the inner fin (2). As the tightening force increases, the groove bevel (511) forces the side surface (22) of the inner fin (2) to adhere tightly to the inner wall of the pressure tube (1). S3. After the inner fin (2) is pre-installed in the pressure tube (1), the pressure tube (1) with the inner fin (2) and the forming tool is placed on a movable bonding table (8); the movable bonding table (8) includes a phase indexing head (81) and a linear guide slide (82); S4. During the bonding process, the phase indexing head (81) drives the pressure-bearing tube (1) to rotate circumferentially, and the linear guide slide (82) drives the fully automatic dispensing machine to move continuously and smoothly in the axial direction; the needle (10) for dispensing glue is drawn out from the fully automatic dispensing machine (9); the needle (10) extends from a side port of the pressure-bearing tube (1) into the pressure-bearing tube (1) through the central fan-shaped hole of the circumferential limit flange (3) and the expansion flange (5), and the end of the needle (10) contacts the side surface (22) where the inner wall of the pressure-bearing tube (1) and the inner fin (2) are in contact; S5. As the thermal conductive silica gel (11) is squeezed out from the end of the needle (10), the linear guide slide (82) drives the fully automatic glue dispenser to move horizontally at a constant speed, thereby achieving the glue bonding operation between the side surface (22) of the inner fin (2) and the inner wall of the pressure tube (1) at half the length of the pressure tube (1); the phase dividing head (81) drives the pressure tube (1) to rotate to a set angle, and the needle (10) is inserted into the pressure tube (1) again, and the operation is repeated until the phase dividing head (81) completes a 360° rotation; S6. Turn the port of the pressure-bearing tube (1), insert the needle (10) from the other port of the pressure-bearing tube (1), and perform the gluing operation again; until all the inner fins (2) are bonded to the pressure-bearing tube (1), and after the heat-conducting silica gel (11) is solidified, loosen the nuts screwed on both ends of the limit rod (6) and the expansion rod (7), and withdraw the circumferential limit flange (3), axial limit flange (4), expansion flange (5), limit rod (6), and expansion rod (7) of the forming tool from the inside of the pressure-bearing tube (1); realize the fixed connection of the inner fins (2) to the pressure-bearing tube (1) in a circumferentially uniform manner.

8. The forming method of an internal fin pressure tube according to claim 7, characterized in that: The inner diameter of the needle (10) is 0.3 mm, the outer diameter is 0.6 mm, and the length is 500 mm.

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