A heat exchanger based on three-period minimal surface optimization and a design method thereof

Abstract

This invention belongs to the field of heat exchanger technology, specifically relating to a heat exchanger and its design method based on three-period minimum surface optimization. The heat exchanger based on three-period minimum surface optimization includes two fluid channels formed by a three-period minimum surface structure, with different equivalent diameters. The different equivalent diameters of the two fluid channels in this invention allow for better performance in gas-liquid heat exchangers. When applied to gas-liquid heat exchangers, the channel with the larger equivalent diameter is the liquid channel, and the channel with the smaller equivalent diameter is the gas channel, thus improving the overall performance of the heat exchanger.

Description

Technical Field

[0001] This invention belongs to the field of heat exchanger technology, specifically relating to a heat exchanger and its design method based on three-period minimum surface optimization. Background Technology

[0002] With the rapid development of additive manufacturing (3D printing) technology, TPMS (Printed Circuit Board System) heat exchangers, as a novel heat exchange structure, have attracted widespread attention in the industry due to their powerful heat transfer performance and compact, conformal structure. Currently, the research and application of TPMS heat exchangers are mainly in the aerospace field and have not yet been applied in power plant equipment. As a highly efficient and compact heat exchanger, TPMS heat exchangers offer better heat transfer performance and higher compactness than PCHE (Printed Circuit Board Heat Exchanger). Furthermore, combined with 3D printing technology, they can achieve flexible and precise manufacturing of complex shapes, showing broad application prospects.

[0003] TPMS is a curved surface with a constant average curvature of 0 arranged periodically in three directions in space. It has various equation forms, commonly including Diamond, Gyroid, and Schwarz-P. The TPMS wall divides the space into two independent spaces for fluid flow and heat exchange on both sides. Its advantages include a large surface area per unit volume, smooth and continuous curved channels, and high mechanical strength and stiffness, all of which are beneficial for its application in heat exchanger design.

[0004] Currently, in the design of TPMS heat exchangers, the internal solid wall is mostly obtained by offsetting the curved surface by the same distance on both sides, which makes the volume of the two fluid channels basically the same, that is, the equivalent flow diameter is the same. When applied to gas-liquid heat exchange, the physical properties of the fluids on both sides are very different. When flowing in channels with the same equivalent diameter, the flow and heat transfer characteristics are very different, and the optimal heat exchange effect cannot be achieved. Summary of the Invention

[0005] The present invention addresses the above-mentioned technical problems by providing a heat exchanger and its design method based on three-period minimum surface optimization.

[0006] A heat exchanger based on three-period minimum surface optimization, the heat exchanger comprising two fluid channels formed by a three-period minimum surface structure, the two fluid channels having different equivalent diameters.

[0007] Optionally, the volume and equivalent diameter of one of the fluid channels are greater than the volume and equivalent diameter of the other fluid channel.

[0008] Optionally, the three-period minimal surface structure also constitutes a solid structure, which divides the two fluid channels into two independent channels.

[0009] The heat exchanger also includes:

[0010] A housing, wherein the housing is disposed outside the three-period minimal surface structure;

[0011] Two sets of connectors, one set of which has two connectors connected to both ends of one fluid channel for the inlet and outlet of one medium; the other set of which has two connectors connected to both ends of another fluid channel for the inlet and outlet of another medium.

[0012] Optionally, the heat exchanger is a gas-liquid heat exchanger, and of the two fluid channels, the fluid channel with the larger equivalent diameter is the liquid channel, and the fluid channel with the smaller equivalent diameter is the gas channel.

[0013] A design method for a heat exchanger based on three-period minimum surface optimization, the design method comprising:

[0014] S1, Define the surface function of the three-period minimal surface structure based on the single period size a. ,in For spatial coordinate variables;

[0015] S2, in Generate within space A curved surface, on which n vertices are uniformly selected. ;

[0016] S3, calculate the unit normal vector of the surface at each point, using the following formula:

[0017]

[0018] S4, offsetting all vertices on the surface by a distance d to one side, is calculated using the following formula:

[0019]

[0020] S5, based on the designed wall thickness t, offset all vertices of the curved surface to both sides by a distance. The calculation formula is:

[0021]

[0022]

[0023] S6 connects the two point sets respectively. and Thus, the two side walls of the heat exchanger's solid structure are obtained;

[0024] S7 generates a solid structure between the two side walls, thus obtaining the solid structure of the heat exchanger in a single cycle;

[0025] S8, periodically arrays the solid structure within a single period in three directions to generate The three-period minimal surface structure, in which The number of cycles in each direction;

[0026] S9. The three-period minimal surface structure obtained in step S8 is trimmed to the required external dimensions, and a shell and nozzle are generated on the boundary to obtain a heat exchanger with two fluid channels of different equivalent diameters.

[0027] Optionally, the design method further includes:

[0028] S10. Using numerical simulation, find the offset distance d that meets the preset heat exchange requirements and complete the design of the heat exchanger.

[0029] Optionally, if the surface function is the Diamond surface function, then in step S1, the surface function is:

[0030] .

[0031] Optionally, if the surface function is a Gyroid surface function, then in step S1, the surface function is:

[0032] .

[0033] Optionally, if the surface function is a Primitive surface function, then in step S1, the surface function is:

[0034] .

[0035] Optionally, for a heat exchanger with a single cycle size a of 10 mm and a wall thickness t of 1 mm, the offset distance d is 0.25 mm to 0.75 mm.

[0036] Beneficial effects: The present invention has at least one or more of the following advantages:

[0037] 1. The heat exchanger of the present invention has two fluid channels with different equivalent diameters. When applied to a gas-liquid heat exchanger, the channel with the larger equivalent diameter is the liquid channel and the channel with the smaller equivalent diameter is the gas channel, which can improve the overall performance of the heat exchanger.

[0038] 2. This invention establishes a solid region by offsetting the TPMS to both sides by different distances, which can divide the space into two flow domains of different volumes, thereby making the equivalent diameters of the two fluid channels of the heat exchanger different. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a heat exchanger according to the present invention;

[0040] Figure 2This is a partial internal structural cross-sectional view of the heat exchanger of the present invention. Detailed Implementation

[0041] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to better understand the purpose, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are only for illustrating the essential spirit of the technical solution of the present invention.

[0042] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0043] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0044] In the following description, in order to clearly demonstrate the structure and operation of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0045] Reference Figure 1 and Figure 2 This invention provides a heat exchanger based on a three-period minimum surface optimization. The heat exchanger includes two fluid channels formed by a three-period minimum surface structure 10, namely fluid channel 11 and fluid channel 12, and the two fluid channels have different equivalent diameters.

[0046] When the heat exchanger of the present invention is applied to scenarios where the physical properties of two media differ significantly, such as in a gas-liquid heat exchanger, the overall performance of the heat exchanger can be improved because the equivalent diameters of the two fluid channels are different. When the two media with significantly different physical properties flow in channels with different equivalent diameters, the overall performance of the heat exchanger can be improved.

[0047] In one embodiment, the volume and equivalent diameter of one fluid channel are greater than the volume and equivalent diameter of another fluid channel.

[0048] like Figure 2As shown, the volume and equivalent diameter of fluid channel 12 are greater than those of fluid channel 11.

[0049] In one embodiment, reference is made to Figure 1 and Figure 2 The heat exchanger also includes a solid structure 13 composed of a three-period minimal curved surface structure 10, which divides the fluid channel 11 and the fluid channel 12 into two independent channels.

[0050] The heat exchanger also includes a shell 20 and several connecting pipes 30.

[0051] The shell 20 is disposed outside the three-period minimal curved surface structure 10.

[0052] Among the several connecting pipes 30, two connecting pipes 30 form a group; the two connecting pipes 30 in one group are respectively connected to the two ends of the fluid channel 11 for the inlet and outlet of one medium; the two connecting pipes 30 in the other group are respectively connected to the two ends of the fluid channel 12 for the inlet and outlet of another medium.

[0053] In one embodiment, the heat exchanger is a gas-liquid heat exchanger, and of the two fluid channels, the fluid channel with the larger equivalent diameter is the liquid channel, and the fluid channel with the smaller equivalent diameter is the gas channel.

[0054] In this embodiment, the gas-liquid heat exchanger has a significant difference in the physical properties of the two media, such as in air-water heat exchange scenarios and natural gas-water heat exchange scenarios. The channel with the larger equivalent diameter is the liquid channel, and the channel with the smaller equivalent diameter is the gas channel, which can improve the overall performance of the heat exchanger.

[0055] This invention also provides a design method for a heat exchanger based on three-period minimum surface optimization, which specifically includes the following steps:

[0056] S1, Define the surface function of the three-period minimal surface structure based on the single period size a. ,in For spatial coordinate variables;

[0057] S2, in Generate within space A curved surface, on which n vertices are uniformly selected. ;

[0058] S3, calculate the unit normal vector of the surface at each point, using the following formula:

[0059]

[0060] S4, offsetting all vertices on the surface by a distance d to one side, is calculated using the following formula:

[0061]

[0062] S5, based on the designed wall thickness t, offset all vertices of the curved surface to both sides by a distance. The calculation formula is:

[0063]

[0064]

[0065] S6 connects the two point sets respectively. and Thus, the two side walls of the heat exchanger's solid structure are obtained;

[0066] S7 generates a solid structure between the two side walls, thus obtaining the solid structure of the heat exchanger in a single cycle;

[0067] S8, periodically arrays the solid structure within a single period in three directions to generate The three-period minimal surface structure, in which The number of cycles in each direction;

[0068] S9. The three-period minimal surface structure obtained in step S8 is trimmed to the required external dimensions, and a shell and nozzle are generated on the boundary to obtain a heat exchanger with two fluid channels of different equivalent diameters.

[0069] S10. Using numerical simulation, find the offset distance d that meets the preset heat exchange requirements and complete the design of the heat exchanger.

[0070] TPMS surfaces are typically defined by implicit equations This indicates that several common TPMS surfaces include:

[0071] 1. Diamond surface:

[0072]

[0073] 2. Gyroid surface:

[0074]

[0075] 3. Primitive surface:

[0076]

[0077] when When the above surface can divide the space into two subdomains of equal volume, the heat exchanger is typically designed based on equidistant surfaces offset from the TPMS surface on both sides. The area between the two equidistant surfaces is taken as the solid region of the heat exchanger. The heat exchanger modeled using this method has the same volume and equivalent diameter for the two fluid channels.

[0078] For heat exchange scenarios where the physical properties of the two media differ significantly, a heat exchanger with identical fluid channel volumes and equivalent diameters is clearly unsuitable. Therefore, this invention establishes a solid region by offsetting the TPMS (Transient Thermal Mass Module) to both sides by different distances, thereby creating a heat exchanger with different equivalent diameters for the two fluid channels, making it suitable for heat exchange scenarios where the physical properties of the two media differ significantly.

[0079] In one embodiment, the surface function is the Diamond surface function, then in step S1, the surface function is:

[0080] .

[0081] In one embodiment, the surface function is the Gyroid surface function, then in step S1, the surface function is:

[0082] .

[0083] In one embodiment, the surface function is a Primitive surface function, then in step S1, the surface function is:

[0084] .

[0085] Of course, the surface functions of the present invention are not limited to the above three cases. All surface functions of TPMS surfaces in the prior art are applicable to the present invention.

[0086] In one embodiment, for a heat exchanger with a single cycle size a of 10 mm and a wall thickness t of 1 mm, the offset distance d is 0.25 mm to 0.75 mm.

[0087] Specifically, the offset distance d is, for example, 0.25 mm, 0.5 mm, or 0.75 mm.

[0088] Example 1:

[0089] This embodiment is based on a Diomand surface, with a heat exchanger having a single cycle size of 10mm × 10mm × 10mm and a wall thickness of 1mm. The offset distances to one side are 0.25mm, 0.5mm, and 0.75mm, respectively. The volume and equivalent diameter between the two fluid channels obtained using the design method of this invention are shown in the table below:

[0090]

[0091] The input parameters for the heat exchanger are as follows: the two media are water and air, the water side inlet temperature is 200℃ and the pressure is 9MPa, and the air side inlet temperature is 15℃ and the pressure is 3.5MPa.

[0092] The heat exchange performance of the four structures above was compared using numerical simulation. The overall performance of the heat exchangers was evaluated using the Performance Evaluation Criteria (PEC).

[0093]

[0094] in, The Nusselt number characterizes the heat transfer intensity after structural displacement. The friction factor characterizes the flow resistance after structural offset. and The values ​​are the Nusselt number and friction factor under the no-offset condition, respectively, serving as a reference.

[0095] This indicates that the overall performance of the heat exchanger is better than the reference standard. The comparison of the four PEC structures is shown in the table below:

[0096]

[0097] The above results show that, for gas-liquid heat exchange, the heat exchanger optimized by shifting the TPMS structure to one side can improve overall performance by more than 10% compared to a heat exchanger with the same volume on both sides.

[0098] The preferred embodiments of the present invention have been described in detail above. However, it should be understood that after reading the above teachings, those skilled in the art can make various alterations or modifications to the present invention. These equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A heat exchanger based on three-period minimum surface optimization, characterized in that, The heat exchanger includes two fluid channels composed of a three-period minimal surface structure, and the two fluid channels have different equivalent diameters.

2. The heat exchanger as described in claim 1, characterized in that, The volume and equivalent diameter of one of the fluid channels are greater than the volume and equivalent diameter of the other fluid channel.

3. The heat exchanger as described in claim 1, characterized in that, The three-period minimal surface structure also constitutes a solid structure, which divides the two fluid channels into two independent channels. The heat exchanger also includes: A housing, wherein the housing is disposed outside the three-period minimal surface structure; Two sets of connectors, one set of which has two connectors connected to both ends of one fluid channel for the inlet and outlet of one medium; the other set of which has two connectors connected to both ends of another fluid channel for the inlet and outlet of another medium.

4. The heat exchanger according to any one of claims 1 to 3, characterized in that, The heat exchanger is a gas-liquid heat exchanger. Of the two fluid channels, the fluid channel with the larger equivalent diameter is the liquid channel, and the fluid channel with the smaller equivalent diameter is the gas channel.

5. A design method for a heat exchanger based on three-period minimum surface optimization as described in any one of claims 1 to 4, the design method comprising: S1, Define the surface function of a three-period minimal surface structure based on the single period size a. ,in For spatial coordinate variables; S2, in Generate within space A curved surface, on which n vertices are uniformly selected. ; S3, calculate the unit normal vector of the surface at each point, using the following formula: ； S4, offsetting all vertices on the surface by a distance d to one side, is calculated using the following formula: ； S5, based on the designed wall thickness t, offset all vertices of the curved surface to both sides by a distance. The calculation formula is: ； ； S6 connects the two point sets respectively. and Thus, the two side walls of the heat exchanger's solid structure are obtained; S7 generates a solid structure between the two side walls, thus obtaining the solid structure of the heat exchanger in a single cycle; S8, periodically arrays the solid structure within a single period in three directions to generate The three-period minimal surface structure, in which The number of cycles in each direction; S9. The three-period minimal surface structure obtained in step S8 is trimmed to the required external dimensions, and a shell and nozzle are generated on the boundary to obtain a heat exchanger with two fluid channels of different equivalent diameters.

6. The design method as described in claim 5, characterized in that, The design method further includes: S10. Using numerical simulation, find the offset distance d that meets the preset heat exchange requirements and complete the design of the heat exchanger.

7. The design method as described in claim 5, characterized in that, If the surface function is the Diamond surface function, then in step S1, the surface function is: 。 8. The design method as described in claim 5, characterized in that, If the surface function is a Gyroid surface function, then in step S1, the surface function is: 。 9. The design method as described in claim 5, characterized in that, If the surface function is a Primitive surface function, then in step S1, the surface function is: 。 10. The design method as described in claim 5, characterized in that, For a heat exchanger with a single cycle size a of 10 mm and a wall thickness t of 1 mm, the offset distance d is 0.25 mm to 0.75 mm.

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