A 3D-printed shell-and-tube two-stage heat exchanger and its fabrication method

Abstract

This invention discloses a 3D-printed, two-stage heat exchanger with a shell and its fabrication method, belonging to the technical field of heat exchangers for compressors. It includes a shell, a primary heat flow pipe, and a secondary heat flow pipe. The shell contains a spirally folded primary heat flow pipe and a secondary heat flow pipe arranged in three-dimensional space. The two ends of the primary heat flow pipe are connected to a primary heat flow inlet and a primary heat flow outlet, respectively. The two ends of the secondary heat flow pipe are connected to a secondary heat flow inlet and a secondary heat flow outlet, respectively. Cooling fluid channels are formed on the outer sides of the primary and secondary heat flow pipes, and these channels are connected at the primary and secondary heat flow inlets and outlets. Cooling fluid flows sequentially along these channels through the primary heat flow outlet, primary heat flow inlet, secondary heat flow outlet, and secondary heat flow inlet. This invention achieves miniaturization and significantly improves heat exchange efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of heat exchangers for compressors, specifically relating to a shell-and-tube two-stage heat exchanger based on 3D printing and its preparation method. Background Technology

[0002] With the upgrading of industrial activities, the demand for high-pressure fluids is increasing, prompting higher efficiency requirements for compressors with higher compression ratios. As the compression ratio increases, the compressor's exhaust temperature also rises, making heat dissipation a more prominent issue and one of the challenges that needs to be overcome in this field. Using heat exchangers to effectively cool high-temperature fluids is the most direct way to solve this problem. However, due to the space constraints of compressors and the need for efficient heat exchange, traditional shell-and-tube or plate heat exchangers often struggle to meet these requirements.

[0003] Furthermore, traditional heat exchangers typically require assembly of profiles through welding or bolting during manufacturing. These methods suffer from drawbacks such as high welding difficulty, complex structure, susceptibility to leaks, and large size. To improve heat transfer efficiency, the design of tube bundles and shells becomes even more complex, undoubtedly increasing production difficulty. Therefore, the heat exchanger field requires a design with high thermal conductivity that can overcome these problems and is easy to manufacture. 3D printing-based heat exchanger manufacturing methods have emerged to address this need. Existing additive manufacturing technology, also known as 3D printing, uses materials such as plastics, polymers, metals, ceramics, or resins to create physical products. Compared to traditional machining, 3D printing offers advantages such as lightweight design, cost-effectiveness, high production efficiency, and integration, and can customize complex products according to customer needs. This technology has already been widely applied in various fields such as aerospace and medical devices. Among these, the time efficiency of 3D printing and the effects of thermal stress and vibration during printing are core considerations in its development. Summary of the Invention

[0004] The purpose of this invention is to provide a 3D-printed shell-and-tube two-stage heat exchanger and its fabrication method, aiming to design a miniaturized and highly efficient 3D-printed heat exchanger.

[0005] This invention is mainly achieved through the following technical solutions:

[0006] A 3D-printed, shell-and-tube two-stage heat exchanger includes a shell, a primary heat flow pipe, a secondary heat flow pipe, and a baffle. The shell contains a primary heat flow pipe and a secondary heat flow pipe arranged in a spiral pattern that folds back and forth in three-dimensional space. A primary heat flow outlet and a secondary heat flow inlet are respectively located at the left and right ends of the upper middle part of one side of the shell, and a primary heat flow inlet is located at the lower end of the other side of the shell. A secondary heat flow outlet is located at the lower left end of the shell. The two ends of the primary heat flow pipe are connected to the primary heat flow inlet and the primary heat flow outlet, respectively, and the two ends of the secondary heat flow pipe are connected to the secondary heat flow inlet and the secondary heat flow outlet, respectively.

[0007] The outer sides of the primary and secondary hot flow pipes are respectively enclosed by baffles along the pipe's direction, forming cooling fluid channels on the outer sides of the primary and secondary hot flow pipes. The cooling fluid channels at the primary hot flow inlet and the secondary hot flow outlet are connected. A cold flow inlet and a cold flow outlet, which are connected to the cooling fluid channels, are respectively provided on one side of the primary hot flow outlet and the secondary hot flow inlet, so that the cooling fluid enters the cooling fluid channel from the cold flow inlet, and sequentially passes through the primary hot flow outlet, the primary hot flow inlet, the secondary hot flow outlet, and the secondary hot flow inlet, and finally exits through the cold flow outlet.

[0008] To better realize the present invention, the primary heat flow pipe and the secondary heat flow pipe each include several rows of interconnected heat flow units. The heat flow unit is a pipe arranged in an S-shape with repeated bends from top to bottom, and a partition is provided between adjacent bends and on the outside of the pipe. Adjacent heat flow units are connected by arc-shaped pipes.

[0009] To better realize the present invention, a primary heat flow pipe and a secondary heat flow pipe are respectively provided on the left and right sides of the shell. The tail end of the secondary heat flow pipe passes through the rear side of the shell through a heat exchange pipe and is connected to the secondary heat flow outlet on the left side of the shell.

[0010] To better realize the present invention, the shell and the partition are further connected to the primary heat flow pipe and the secondary heat flow pipe respectively through the pipe wall connection structure.

[0011] To better realize the present invention, a through connection hole is further provided on the adjacent pipe wall connection structure, and the diameter of the connection hole is 1.5mm~2mm, so that the heat exchanged flow can flow in the connection hole.

[0012] To better realize the present invention, the shell-and-tube two-stage heat exchanger is further installed in the irregular envelope space between the two-stage cylinders of the two-stage V-type compressor.

[0013] This invention is mainly achieved through the following technical solutions:

[0014] A method for fabricating a 3D-printed coaxial two-stage heat exchanger, used to fabricate the aforementioned 3D-printed coaxial two-stage heat exchanger, employing fused deposition modeling (FDM) 3D printing to produce an integrated coaxial two-stage heat exchanger; including the following steps:

[0015] Step S1: Import the 3D model of the shell-and-tube two-stage heat exchanger, slice it using slicing software to obtain the layer contour, where the cross-section of the baffle and the primary heat flow pipe / secondary heat flow pipe is used as a contour unit.

[0016] Step S2: Divide the layer contour into several printing areas, and each printing area includes an integer number of contour units; print the contour units in the printing areas alternately, and the printing time of each area at one time is less than or equal to the maximum continuous printing time to avoid overheating of the area;

[0017] Step S3: Find the optimal printing path based on the ant colony algorithm;

[0018] The alternating printing path is regarded as the path ants take to find food, and the release of pheromones guides subsequent jumps to choose a better path;

[0019] The probability of an ant choosing the next jump point is determined by both the pheromone concentration of the current path and the reciprocal of the distance.

[0020] By iteratively updating the pheromone matrix, the jump order converges to the one with the minimum total empty travel distance, while also satisfying the cooldown time constraints for each region.

[0021] To better realize the present invention, further, in step S2, the maximum continuous printing time is the printing cooling time of a single contour unit.

[0022] To better realize the present invention, further, in step S2, optimizing the printing parameters of each printing area includes the following steps:

[0023] Step S21: Taking into account both printing efficiency and printing quality, determine the optimal printing parameters (traverse time, printing speed, travel acceleration, printing temperature) for each printing area; among which, the optimization objectives include minimizing the standard deviation of acceleration, maximizing the filling rate, and minimizing the forming time.

[0024] Step S22: The optimal printing parameters of each printing area are used as candidate variables and input into a multi-objective particle swarm optimization model to optimize the global process parameters and obtain the optimal parameter combination for the printing process.

[0025] The beneficial effects of this invention are as follows:

[0026] (1) This invention achieves a miniaturized heat exchanger design with uniform internal flow heat exchange. It realizes two-stage heat exchange through primary and secondary heat flow pipes, significantly improving heat exchange efficiency. Specifically, this invention places the cold flow inlet next to the primary heat flow outlet and the cold flow outlet next to the secondary heat flow inlet, allowing the cold flow fluid to pass sequentially through the primary heat flow outlet, primary heat flow inlet, secondary heat flow outlet, and secondary heat flow inlet, resulting in more thorough heat exchange and ensuring that the two heat source fluids simultaneously achieve optimal heat exchange effects, greatly improving the heat exchanger's efficiency. This invention is based on 3D printing for one-time molding, eliminating the need for additional piping connections, further achieving miniaturization and demonstrating good practicality.

[0027] (2) This invention forms a heat source fluid channel (heat flow pipe) by folding circular pipes in three-dimensional space. This not only enhances the convective heat transfer effect of the spiral tube by adding bends, ensuring the heat transfer performance and flow resistance performance of the fluid, but also adapts to the irregular envelope space around the compressor, realizing conformal design and expanding the design freedom. Secondly, the partitions inserted between the folded circular pipes in this invention, through reasonable spacing design and pipe wall connection structure design, not only ensure the uniformity of the low-temperature fluid channel, which is conducive to improving heat exchange efficiency, but also facilitate the realization of 3D printing technology, while ensuring the structural strength of the heat exchanger.

[0028] (3) This invention divides the printing area and uses the cooling time of the contour unit as the maximum continuous printing time, which avoids excessive heat accumulation, material softening, and collapse caused by continuous, long-term printing in local areas. Furthermore, it converges to the minimum total idle distance based on the ant colony algorithm, satisfying the cooling time constraints of each area, thus obtaining the optimal printing path planning. Secondly, based on the printing parameters of each area, this invention uses a multi-objective particle swarm optimization model to optimize global process parameters, obtaining the optimal parameter combination that maximizes overall printing stability. This invention allocates a printing time slice to each printing area, and each time slice is very short, ensuring that no area overheats. This invention's time-based printing division is a cutting-edge direction in 3D printing path planning. It transcends the geometric thinking of static 3D printing, treating the printing process as a dynamic system for optimization. Although computationally complex, it has enormous potential for improving printing speed, quality, and reliability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the connection structure between the shell-and-tube two-stage heat exchanger and the two-stage V-type gas compressor in Example 1;

[0030] Figure 2 This is a perspective structural diagram of the 3D-printed double-stage heat exchanger based on the present invention.

[0031] Figure 3 for Figure 2 A three-dimensional cross-sectional view of the right side of a double-stage heat exchanger with a central tube casing.

[0032] Figure 4 This is a schematic diagram of the internal S-shaped repeatedly bent pipe structure of a shell-and-tube two-stage heat exchanger.

[0033] Figure 5 This is a schematic diagram of the connection structure between the internal baffle and the tube wall of a shell-and-tube two-stage heat exchanger.

[0034] Figure 6 This is a flowchart of the fabrication method of the shell-and-tube two-stage heat exchanger based on 3D printing according to the present invention.

[0035] Wherein: 1- Primary heat flow pipe, 2- Secondary heat flow pipe, 3- Baffle, 4- Shell, 5- Cooling fluid passage, 6- Primary heat flow outlet, 7- Primary heat flow inlet, 8- Secondary heat flow outlet, 9- Secondary heat flow inlet, 10- Cold flow inlet, 11- Cold flow outlet, 12- Pipe wall connection structure. Detailed Implementation

[0036] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., used to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this invention is usually placed in during use. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this invention does not imply that the components are required to be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0038] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Example 1:

[0040] A 3D-printed coaxial two-stage heat exchanger is applied to a two-stage V-type gas compressor, such as... Figure 1 As shown, the shell-and-tube two-stage heat exchanger can make good use of the irregular envelope space between the two-stage cylinders of the two-stage V-type gas compressor, and minimize the space volume occupied by the compressor system while meeting the heat exchange performance requirements.

[0041] like Figure 2 As shown, a primary heat flow outlet 6 and a secondary heat flow inlet 9 are respectively provided at the left and right ends of the upper middle part of one side of the housing 4, and a primary heat flow inlet 7 is provided at the lower end of the other side of the housing 4. A secondary heat flow outlet 8 is provided at the lower left end of the housing 4. The two ends of the primary heat flow pipe 1 are connected to the primary heat flow inlet 7 and the primary heat flow outlet 6 respectively, and the two ends of the secondary heat flow pipe 2 are connected to the secondary heat flow inlet 9 and the secondary heat flow outlet 8 respectively.

[0042] The outer sides of the primary heat flow pipe 1 and the secondary heat flow pipe 2 are respectively surrounded by baffles 3 along the pipe direction, so that cooling fluid channels 5 are respectively formed on the outer sides of the primary heat flow pipe 1 and the secondary heat flow pipe 2. The cooling fluid channels 5 at the primary heat flow inlet 7 and the secondary heat flow outlet 8 are connected. The primary heat flow outlet 6 and the secondary heat flow inlet 9 are respectively provided with a cold flow inlet 10 and a cold flow outlet 11 connected to the cooling fluid channels 5, so that the cooling fluid enters the cooling fluid channel 5 from the cold flow inlet 10, and passes through the primary heat flow outlet 6, the primary heat flow inlet 7, the secondary heat flow outlet 8, and the secondary heat flow inlet 9 in sequence along the cooling fluid channel 5, and finally exits through the cold flow outlet 11.

[0043] During the heat exchange process in the heat exchanger, two stages of heat flow enter the primary heat flow inlet 7 and the secondary heat flow inlet 9, respectively. They flow within the primary heat flow pipe 1 and the secondary heat flow pipe 2, transferring heat to the outer walls of the pipes, and then exit through the primary heat flow outlet 6 and the secondary heat flow outlet 8. The partition 3 and the shell 4, intersecting between the two stages of heat flow pipes, together with the outer walls of the primary and secondary heat flow pipes 1 and 2, form a cooling fluid channel 5. The cooling fluid enters the cold flow inlet 10, then exchanges heat with the outer walls of the two stages of heat flow pipes, and exits through the cold flow outlet 11. The cooling fluid channel 5, starting from the cold flow inlet 10, sequentially passes through the primary heat flow outlet 6, the primary heat flow inlet 7, the secondary heat flow outlet 8, and the secondary heat flow inlet 9, ensuring that a suitable temperature difference is maintained between the heat source fluid and the cooling fluid at all times, increasing the heat flux per unit area, and thus improving heat exchange efficiency.

[0044] Preferably, a primary heat flow pipe 1 and a secondary heat flow pipe 2 are respectively provided on the left and right sides of the housing 4. The tail end of the secondary heat flow pipe 2 passes through the rear side of the housing 4 via a heat exchange pipe and is connected to the secondary heat flow outlet 8 on the left side of the housing 4. The primary heat flow pipe 1 and the secondary heat flow pipe 2 each include several rows of connected heat flow units. The heat flow units are pipes arranged in an S-shaped repeated bend from top to bottom, and partitions 3 are respectively provided between adjacent bends and on the outside of the pipes; adjacent heat flow units are connected by arc-shaped pipes.

[0045] like Figure 3 As shown, the spacing of the baffles 3 is uniform, ensuring that the cross-sectional area of ​​the cooling fluid channel 5 is the same at all points. This not only improves the uniformity and sufficiency of the heat exchange process but also guarantees consistent flow resistance and pipe wall strength at all points. Furthermore, the uniform design facilitates 3D printing technology and reduces unnecessary consumption of support materials. The diameters of the primary heat flow pipe 1, the secondary heat flow pipe 2, and the cooling fluid channel 5 can be adjusted according to different flow rate and pressure requirements to achieve optimal heat exchange performance.

[0046] Preferably, such as Figure 4 and Figure 5 As shown, the heat exchanger has pipe wall connection structures 12 between the shell 4 and the primary heat flow pipe 1, between the primary heat flow pipe 1 and the partition 3, between the secondary heat flow pipe 2 and the partition 3, and between the secondary heat flow pipe 2 and the shell 4. This allows the heat exchanger to meet the requirements for 3D printing structure manufacturing and to be manufactured in one step using fused deposition modeling (FDM) 3D printing equipment. Preferably, the pipe wall connection structure 12 has a through connection hole with a diameter of 1.5mm to 2mm, allowing the heat flow to pass through it, increasing the heat exchange area while ensuring the manufacturability of the structure.

[0047] Example 2:

[0048] A method for fabricating a shell-and-tube two-stage heat exchanger based on 3D printing, such as Figure 6 As shown, it includes the following steps:

[0049] Step S1: Import the 3D model of the shell-and-tube two-stage heat exchanger, slice it using slicing software to obtain the layer contour, wherein the cross-section of the partition 3 and the primary heat flow pipe 1 / secondary heat flow pipe 2 is used as a contour unit.

[0050] Step S2: Divide the layer contour into several printing areas, and each printing area includes an integer number of contour units; print the contour units in the printing areas alternately, and the printing time of each area at one time is less than or equal to the maximum continuous printing time to avoid overheating of the area;

[0051] Optimize printing parameters for each printing area:

[0052] (1) Taking into account both printing efficiency and printing quality, determine the optimal printing parameters (movement time, printing speed, movement acceleration, printing temperature) for each printing area; among which, the optimization objectives include minimizing the standard deviation of acceleration, maximizing the filling rate, and minimizing the forming time.

[0053] (2) The optimal printing parameters of each printing area are used as candidate variables and input into the multi-objective particle swarm optimization model to optimize the global process parameters and obtain the optimal parameter combination for the printing process.

[0054] Step S3: Based on the ant colony algorithm, find the optimal jumping order;

[0055] The alternating printing path is regarded as the path ants take to find food, and the release of pheromones guides subsequent jumps to choose a better path;

[0056] The probability of an ant choosing the next jump point is determined by both the pheromone concentration of the current path and the reciprocal of the distance.

[0057] By iteratively updating the pheromone matrix, the jump order converges to the one with the minimum total empty travel distance, while also satisfying the cooldown time constraints for each region.

[0058] The multi-objective particle swarm optimization model and ant colony algorithm mentioned above are existing technologies and are not the main improvement points of this invention, so they will not be described in detail.

[0059] This invention transforms the printing path problem into a typical Traveling Salesman Problem (TSP). The print head starts from a point, traverses all the "points" or "line segments" to be printed, and finally returns to the starting point (or does not return), with the goal of minimizing total time and empty travel. Secondly, to avoid excessive heat accumulation, material softening, and collapse caused by continuous long-term printing in different areas, this invention divides each layer contour into multiple geographically dispersed sub-regions (e.g., like a checkerboard pattern). The printing path alternates between different printing regions; for example, printing a small portion of region A first, then jumping to region B to print a portion, then jumping to region C, and finally jumping back to region A to print the next portion. This ensures that when the print head returns to region A, the previously printed portion has sufficient time to cool. This invention allocates a short printing time slice to each printing region to ensure no region overheats. This invention implements skip printing by defining a maximum continuous printing time parameter; once this time threshold is reached in a certain region, printing must switch to another region. This invention uses an ant colony algorithm to find the optimal skip sequence to minimize the total empty travel distance of the print head while satisfying the cooling time constraints of each region.

[0060] This invention divides the printing area and uses the cooling time of the contour unit as the maximum continuous printing time. This avoids excessive heat accumulation, material softening, and collapse caused by continuous, long-term printing in local areas. Based on an ant colony algorithm, it converges to the minimum total idle distance while satisfying the cooling time constraints of each area, resulting in the optimal printing path planning. Furthermore, based on the printing parameters of each area, this invention uses a multi-objective particle swarm optimization model to optimize global process parameters, obtaining the optimal parameter combination that maximizes overall printing stability. This invention allocates a short printing time slice to each printing area, ensuring no area overheats. This time-based printing division is a cutting-edge direction in 3D printing path planning, transcending the geometric thinking of static 3D printing and treating the printing process as a dynamic system for optimization. Although computationally complex, it has enormous potential for improving printing speed, quality, and reliability.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A 3D-printed, two-stage, shell-and-tube heat exchanger, characterized in that, The device includes a shell (4), a primary heat flow pipe (1), a secondary heat flow pipe (2), and a partition (3). The shell (4) is provided with a spiral primary heat flow pipe (1) and a secondary heat flow pipe (2) that are folded back and forth in three-dimensional space. The upper middle part of one side of the shell (4) is provided with a primary heat flow outlet (6) and a secondary heat flow inlet (9) respectively. The lower part of the other side of the shell (4) is provided with a primary heat flow inlet (7). The lower left side of the shell (4) is provided with a secondary heat flow outlet (8). The two ends of the primary heat flow pipe (1) are connected to the primary heat flow inlet (7) and the primary heat flow outlet (6) respectively. The two ends of the secondary heat flow pipe (2) are connected to the secondary heat flow inlet (9) and the secondary heat flow outlet (8) respectively. The outer sides of the primary heat flow pipe (1) and the secondary heat flow pipe (2) are respectively enclosed by baffles (3) along the direction of the pipes, so that the outer sides of the primary heat flow pipe (1) and the secondary heat flow pipe (2) respectively form cooling fluid channels (5). The cooling fluid channels (5) at the primary heat flow inlet (7) and the secondary heat flow outlet (8) are connected. The primary heat flow outlet (6) and the secondary heat flow inlet (9) are respectively provided with a cold flow inlet (10) and a cold flow outlet (11) connected to the cooling fluid channels (5), so that the cooling fluid enters the cooling fluid channel (5) from the cold flow inlet (10) and passes through the primary heat flow outlet (6), the primary heat flow inlet (7), the secondary heat flow outlet (8), and the secondary heat flow inlet (9) in sequence along the cooling fluid channel (5), and finally exits through the cold flow outlet (11). The shell-and-tube two-stage heat exchanger is installed in the irregular envelope space between the two cylinders of the two-stage V-type compressor.

2. The 3D-printed shell-and-tube two-stage heat exchanger according to claim 1, characterized in that, The primary heat flow pipe (1) and the secondary heat flow pipe (2) each include several rows of interconnected heat flow units. The heat flow units are pipes arranged in an S-shape with repeated bends from top to bottom, and partitions (3) are provided between adjacent bends and on the outside of the pipes. Adjacent heat flow units are connected by arc-shaped pipes.

3. A 3D-printed, two-stage, sleeve-type heat exchanger according to claim 2, characterized in that, The shell (4) is provided with a primary heat flow pipe (1) and a secondary heat flow pipe (2) on the left and right sides respectively. The tail end of the secondary heat flow pipe (2) passes through the rear side of the shell (4) through a heat exchange pipe and is connected to the secondary heat flow outlet (8) on the left side of the shell (4).

4. A 3D-printed shell-and-tube two-stage heat exchanger according to any one of claims 1-3, characterized in that, The shell (4) and the partition (3) are respectively connected to the primary heat flow pipe (1) and the secondary heat flow pipe (2) through the pipe wall connection structure (12).

5. A 3D-printed shell-and-tube two-stage heat exchanger according to claim 4, characterized in that, The adjacent pipe wall connection structure (12) is provided with a through connection hole, and the diameter of the connection hole is 1.5mm~2mm, so that the heat exchanged can flow in the connection hole.

6. A method for fabricating a 3D-printed coaxial two-stage heat exchanger, used to fabricate the 3D-printed coaxial two-stage heat exchanger as described in any one of claims 1-5, characterized in that, The integrated shell-and-tube two-stage heat exchanger is manufactured using fused deposition modeling (FDM) 3D printing, including the following steps: Step S1: Import the 3D model of the shell-and-tube two-stage heat exchanger, slice it using slicing software to obtain the layer contour, wherein the cross section of the partition (3) and the primary heat flow pipe (1) / secondary heat flow pipe (2) is a contour unit; Step S2: Divide the layer contour into several printing areas, and each printing area includes an integer number of contour units; print the contour units in the printing areas alternately, and the printing time of each area at one time is less than or equal to the maximum continuous printing time to avoid overheating of the area; In step S2, optimizing the printing parameters for each printing area includes the following steps: Step S21: Taking into account both printing efficiency and printing quality, determine the optimal printing parameters (traverse time, printing speed, travel acceleration, printing temperature) for each printing area; among which, the optimization objectives include minimizing the standard deviation of acceleration, maximizing the filling rate, and minimizing the forming time. Step S22: The optimal printing parameters of each printing area are used as candidate variables and input into the multi-objective particle swarm optimization model to optimize the global process parameters and obtain the optimal parameter combination for the printing process. Step S3: Find the optimal printing path based on the ant colony algorithm; The alternating printing path is regarded as the path ants take to find food, and the release of pheromones guides subsequent jumps to choose a better path; The probability of an ant choosing the next jump point is determined by both the pheromone concentration of the current path and the reciprocal of the distance. By iteratively updating the pheromone matrix, the jump order converges to the one with the minimum total empty travel distance, while also satisfying the cooldown time constraints for each region.

7. The method for fabricating a shell-and-tube two-stage heat exchanger based on 3D printing according to claim 6, characterized in that, In step S2, the maximum continuous printing time is the printing cooling time of a single contour unit.

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