Bending Cooling Channel Structure and TPMS Topological Optimization Method

Abstract

The present invention provides a bent cooling channel structure and a TPMS topology optimization method, including: channels, flow bends, and porous structures; a plurality of the channels are connected by the flow bends, and the porous structures are arranged on the side walls of the channels. The present invention utilizes the porous structures to improve the heat transfer of the bent channels and reduce the flow resistance. Compared with the current bent cooling channels, it obtains significantly improved heat transfer performance, and has smaller flow resistance and pressure loss.

Description

Technical Field

[0001] The present invention relates to the field of cooling channel structures, and specifically, to a bent cooling channel structure and a TPMS topology optimization method; in particular, to a high heat transfer and low pressure loss bent cooling channel structure. Background Art

[0002] In order to improve the thermal efficiency of gas turbines and aero-engines, increasing the gas temperature at the turbine inlet is an important means. Currently, the gas temperature before the turbine is much higher than the working temperature limit of the metal materials used for turbine blades. Therefore, cooling technologies need to be adopted for turbine blades to keep the blade wall temperature within the permitted range. Bent channels are widely used in the internal cooling structures of turbine blades in aero-engines and gas turbines. Bent channels have sufficient flow length and can make the best use of the cooling / heat transfer capacity of a certain flow rate of fluid medium to achieve the turbine cooling goal.

[0003] Modern high-power electronic devices generate a large amount of heat during operation and require efficient and compact heat dissipation or cooling devices to maintain the working temperature of the electronic devices within the permitted range. Bent cooling channels are also widely used in these compact coolers.

[0004] Current problem: Due to the bent flow, obvious flow recirculation dead zones will be generated near the ends of the partitions in the bent channels, resulting in a large flow resistance or pressure loss, and the heat transfer enhancement performance cannot meet the requirements for future improvement of high-efficiency cooling performance. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide a bent cooling channel structure and a TPMS topology optimization method.

[0006] A bent cooling channel structure according to the present invention includes: a first channel, a second channel, a third channel, a first flow bend, a second flow bend, a first porous structure, and a second porous structure;

[0007] The first channel and the second channel are connected through the first flow bend, and the second channel and the third channel are connected through the second flow bend.

[0008] The first porous structure is arranged on the inner side wall of the second channel, and the second porous structure is arranged on the inner side wall of the third channel;

[0009] The width of the first porous structure near the end where the second channel connects to the first flow bend is 0.3 - 0.5 times the width of the second channel;

[0010] The width of the first porous structure near the second flow channel connecting one end of the second flow bend is 0.1 - 0.3 times the width of the second flow channel;

[0011] The length of the first porous structure is 0.5 - 1.0 times the length of the second flow channel.

[0012] Preferably, the first flow channel and the third flow channel are respectively located on both sides of the second flow channel, a first partition is provided between the first flow channel and the second flow channel, and a second partition is provided between the second flow channel and the third flow channel.

[0013] Preferably, the first porous structure is provided on the inner side of the second flow channel near the second partition, and the second porous structure is provided on the inner side of the third flow channel near the second partition.

[0014] Preferably, the outer edge contour of the first porous structure near the second flow channel connecting one end of the first flow bend inclines towards the first partition;

[0015] The outer edge contour of the first porous structure near the second flow channel connecting one end of the second flow bend shrinks towards the second partition.

[0016] Preferably, the width of the first porous structure near the second flow channel connecting one end of the first flow bend is 0.3 - 0.5 times the width of the second flow channel;

[0017] The width of the first porous structure near the second flow channel connecting one end of the second flow bend is 0.1 - 0.3 times the width of the second flow channel;

[0018] The length of the first porous structure is 0.5 - 1.0 times the length of the second flow channel.

[0019] Preferably, the width of the second porous structure is 0.05 - 0.2 times the width of the third flow channel, and the width of the second porous structure extending towards the side of the third flow channel away from the second flow bend gradually decreases.

[0020] Preferably, the porosity of the first porous structure and the second porous structure is 50% - 95%, and the pores of the first porous structure and the second porous structure communicate with the outside in the transverse and longitudinal directions.

[0021] Preferably, the first porous structure and the second porous structure adopt a honeycomb structure, a lattice structure, a pin fin group structure, a microchannel group structure or a triply periodic minimal surface lattice structure (TPMS);

[0022] The topological optimization method of the triply periodic minimal surface lattice structure includes the following steps:

[0023] Step S1, a porous region with intermediate values generated by topology optimization;

[0024] Step S2, filling the porous region with TPMS.

[0025] The wall thickness of the TPMS is associated with the optimized design variable γ in the intermediate value region, and the relationship is: t = t_min + γ × (t_max - t_min) / (γ_max - γ_min);

[0026] Where, t_max is the maximum achievable machining thickness, t_min is the minimum achievable machining thickness; γ_max is the maximum value of the optimized design variable γ (usually 1.0), γ_min is the minimum value of the optimized design variable γ (usually 0);

[0027] γ represents the design variable for generating a new intermediate value region of porous medium in the fluid. The value of γ is between 0 - 1.0; when γ = 0, it represents a solid; when γ = 1.0, it represents a fluid. When the value of γ is between 0 - 1.0, the medium is a porous material.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention utilizes the porous structure to improve heat transfer in the bending channel and reduce flow resistance. Compared with the current bending cooling channel, it obtains significantly improved heat transfer performance, and the flow resistance and pressure loss are smaller;

[0030] 2. The porous structure increases the heat transfer area and improves the overall heat transfer and cooling performance;

[0031] 3. The porous structure improves the flow field in the bending flow channel, reduces the flow recirculation dead zone, and reduces the flow resistance. Description of the Drawings

[0032] By reading the following detailed description of the non - restrictive embodiments with reference to the accompanying drawings, other features, objects, and advantages of the present invention will become more apparent:

[0033] Figure 1 is a schematic diagram of the bending cooling flow channel structure;

[0034] Figure 2 is the intermediate value region generated in the flow channel after topology optimization;

[0035] Figure 3 is filling the intermediate value region with TPMS, and the wall thickness of the TPMS linearly corresponds to the value of γ;

[0036] Figure 4 is the three - dimensional cooling structure in the bending channel after filling the intermediate value region with TPMS;

[0037] Figure 5 is the porous structure of the TPMS;

[0038] As shown in the figure:

[0039] Specific embodiments

[0040] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0041] Embodiment 1

[0042] As Figure 1 shown, this embodiment includes: a first flow channel 21, a second flow channel 22, a third flow channel 23, a first flow bend 31, a second flow bend 32, a first porous structure 41, and a second porous structure 42; the first flow channel 21 and the second flow channel 22 are connected through the first flow bend 31, and the second flow channel 22 and the third flow channel 23 are connected through the second flow bend 32. The first porous structure 41 is arranged on the inner side wall of the second flow channel 22, and the second porous structure 42 is arranged on the inner side wall of the third flow channel 23.

[0043] The first flow channel 21 and the third flow channel 23 are respectively located on both sides of the second flow channel 22. A first partition 11 is arranged between the first flow channel 21 and the second flow channel 22, and a second partition 12 is arranged between the second flow channel 22 and the third flow channel 23. The first porous structure 41 is arranged on the inner side of the second flow channel 22 near the second partition 12, and the second porous structure 42 is arranged on the inner side of the third flow channel 23 near the second partition 12. The outer edge contour of the first porous structure 41 near the end connecting the first flow bend 31 of the second flow channel 22 inclines towards the first partition 11, and the outer edge contour of the first porous structure 41 near the end connecting the second flow bend 32 of the second flow channel 22 contracts towards the second partition 12. The width of the first porous structure 41 near the end connecting the first flow bend 31 of the second flow channel 22 is 0.3 - 0.5 times the width of the second flow channel 22; the width of the first porous structure 41 near the end connecting the second flow bend 32 of the second flow channel 22 is 0.1 - 0.3 times the width of the second flow channel 22; the length of the first porous structure 41 is 0.5 - 1.0 times the length of the second flow channel 22. The width of the second porous structure 42 is 0.05 - 0.2 times the width of the third flow channel 23, and the width of the second porous structure 42 gradually decreases in the direction extending away from the second flow bend 32 of the third flow channel 23.

[0044] The porosity of the first porous structure 41 and the second porous structure 42 is 50%-95%, and the pores of the first porous structure 41 and the second porous structure 42 communicate with the outside in the transverse and longitudinal directions. The porous structure adopts a honeycomb structure, a lattice structure, a pin fin group structure, a microchannel group structure, or a triply periodic minimal surface lattice structure TPMS.

[0045] As Figures 2 to 5 shown, the topology optimization method of the triply periodic minimal surface lattice structure includes the following steps: Step S1, generating a porous region with an intermediate value through topology optimization; Step S2, filling the TPMS into the porous region, and the wall thickness of the TPMS is associated with the optimized design variable γ of the intermediate value region, and the relationship is: t = t_min + γ×(t_max - t_min) / (γ_max - γ_min); where, t_max is the maximum achievable processing thickness, t_min is the minimum achievable processing thickness; γ_max is the maximum value of the optimized design variable γ (usually 1.0), γ_min is the minimum value of the optimized design variable γ (usually 0), γ represents the design variable of the intermediate value region where new porous media are generated in the fluid, and the value of γ is between 0 and 1.0; when γ = 0, it represents a solid; when γ = 1.0, it represents a fluid, and when the value of γ is between 0 and 1.0, the medium is a porous material.

[0046] Example 2

[0047] Example 2 is a preferred example of Example 1.

[0048] As Figure 1 shown, on the left side wall surface of the second flow channel 22 along the flow direction, that is, on the wall surface of the second partition 12, a first porous structure 41 is provided; the first porous structure 41 exists in the region between the upper and lower sides of the second flow channel 22; the first porous structure 41 can be connected to or have a gap with the wall surface of the second partition 12. At the entrance of the second flow channel 22 downstream of the first flow bend 31, the outer edge contour of the first porous structure 41 inclines towards the first partition 11, and the entrance of the second flow channel 22 is tapered, which can eliminate the flow recirculation dead zone near the end of the first partition 11, thereby improving heat transfer and reducing flow resistance. And downstream of the second flow channel 22, the outer edge contour of the first porous structure 41 contracts towards the second partition 12, making the flow expand gradually, which can reduce the flow velocity, thereby reducing the flow separation generated at the second flow bend 32, and is beneficial to improving heat transfer and reducing flow resistance.

[0049] The width of the first porous structure 41 at the entrance of the second flow channel 22 is 0.3 - 0.5 times the width of the second flow channel 22, and the width of the first porous structure 41 gradually contracts along the downstream of the second flow channel 22 and is near the wall surface of the second partition plate 12. The width of the first porous structure 41 at the downstream of the second flow channel 22 is 0.1 - 0.3 times the channel width. The length of the first porous structure 41 is 0.5 - 1.0 times the length of the second flow channel 22. The porosity of the first porous structure 41 is 50% - 95%; the porosity of the first porous structure 41 near the entrance of the second flow channel 22 is smaller, while the porosity of the first porous structure 41 in the downstream area of the second flow channel 22 is larger, which reduces the flow velocity and flow resistance in the downstream area of the second flow channel 22. The pores in the porous structure communicate with the external flow region in the flow direction and the transverse direction.

[0050] A second porous structure 42 is provided on the wall surface of the second partition plate 12 near the entrance of the third flow channel 23; the second porous structure 42 exists on the left wall surface of the entrance of the third flow channel 23. The width of the second porous structure 42 is 0.05 - 0.2 times the width of the third flow channel 23. The width of the second porous structure 42 on the second partition plate 12 at the entrance of the third flow channel 23 is larger, which makes the flow gradually contract and eliminates the flow separation dead zone near the end of the second partition plate 12 at the entrance of the third flow channel 23, which is beneficial to improving heat transfer; while the width of the second porous structure 42 gradually becomes smaller along the downstream of the third flow channel 23, and the flow gradually expands, which is beneficial to reducing resistance. The porosity of the second porous structure 42 is 50% - 95%, and the second porous structure 42 exists between the upper and lower wall surfaces of the third flow channel 23; the second porous structure 42 can be connected to or have a gap with the wall surface of the second partition plate 12. The second porous structure 42 increases the heat transfer area and improves the heat transfer performance. The pore flow in the second porous structure 42 is beneficial to reducing the flow resistance. The pores in the second porous structure 42 communicate with the external flow region in the flow direction and the transverse direction.

[0051] The porous structure can be a honeycomb structure, a lattice structure, a pin fin group structure, a microchannel group structure, or a triply periodic minimal surface (TPMS) lattice and other porous structures with stable structures.

[0052] Topology optimization has become an advanced method for optimizing the performance of fluid and heat transfer systems. Based on the variable density topology optimization method, by increasing the amount of solid in the fluid region, a hypothetical variable porous material with a relative density between 0 and 1 is introduced in the fluid region, so as to achieve the preset optimized values of the flow resistance and heat transfer performance of the fluid system. Due to the good convergence of the variable density method topology optimization and its low dependence on the initial value, it has been widely used.

[0053] Such as Figure 2As shown, the topology optimization of the flow and heat transfer structures using the variable density method will generate a new porous medium in the fluid, called the intermediate value region, where the density of the porous material is between that of the fluid and the solid. The design variable of this intermediate value region can be represented by γ, so the value of γ is between 0 and 1.0. When γ = 0, it represents a solid; when γ = 1.0, it represents a fluid; when the value of γ is between 0 and 1.0, the medium is a porous material. These intermediate value regions generated by topology optimization are irregular porous structures, which are difficult to manufacture and process, and it is also difficult to accurately describe the characteristics of the porous structure, and it cannot ensure that the porous medium obtains sufficient mechanical strength.

[0054] As Figures 3 to 5 shown, through the topology optimization method based on variable density, the characteristics of an innovative bent channel are obtained: to solve the problem that the complex porous structures generated by fluid-heat transfer-structure topology optimization are difficult to machine and manufacture, and have excellent heat transfer, flow resistance and mechanical strength characteristics, this embodiment proposes a new method: using TPMS to fill these porous regions with intermediate values generated by topology optimization, and associating the wall thickness of the TPMS with the optimized design variable γ of the intermediate value region. The TPMS lattice structure is a self-supporting porous structure, with high mechanical strength and a large specific surface area, and can be processed by additive manufacturing.

[0055] In this embodiment, the current minimum thickness t for metal additive manufacturing by the selective laser melting process (SLM) is 0.3 mm, and the set maximum wall thickness for machining is 1.0 mm. Then the TPMS wall thickness corresponding to the region where γ = 0 is t = 1.0 mm, and the thin wall thickness of the TPMS corresponding to the region where γ = 0.9 is t = 0.3 mm. Therefore, the TPMS lattice thickness in the intermediate value region generated by topology optimization varies between 0.3 mm and 1.0 mm, which can be achieved in additive manufacturing.

[0056] Through this method, the complex irregular porous structures generated by topology optimization can be easily manufactured and processed into TPMS porous lattice structures with regular structures, and have self-supporting properties, high strength and large specific surface area. Therefore, they have excellent mechanical strength, as well as excellent heat transfer and flow resistance performance, and realize that the complex high-value structures obtained by topology optimization can be processed by additive manufacturing.

[0057] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application.

[0058] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A TPMS topological optimization method for a bent cooling channel structure, characterized in that, the bent cooling channel structure includes: a first channel (21), a second channel (22), a third channel (23), a first flow bend (31), a second flow bend (32), a first porous structure (41), and a second porous structure (42); the first channel (21) and the second channel (22) are connected through the first flow bend (31), and the second channel (22) and the third channel (23) are connected through the second flow bend (32); the first porous structure (41) is arranged on the inner side wall of the second channel (22), and the second porous structure (42) is arranged on the inner side wall of the third channel (23); the width of the first porous structure (41) near the end where the second channel (22) connects to the first flow bend (31) is 0.3 - 0.5 times the width of the second channel (22); the width of the first porous structure (41) near the end where the second channel (22) connects to the second flow bend (32) is 0.1 - 0.3 times the width of the second channel (22); the length of the first porous structure (41) is 0.5 - 1.0 times the length of the second channel (22); the first porous structure (41) and the second porous structure (42) adopt a triply periodic minimal surface lattice structure TPMS; the method includes the following steps: Step S1, generating a porous region with an intermediate value through topological optimization; Step S2, filling the porous region with TPMS; The wall thickness of the TPMS is associated with the optimized design variable γ of the porous region with an intermediate value, and the relationship is: t = t_min + γ×(t_max - t_min) / (γ_max - γ_min); where, t is the wall thickness of the TPMS, t_max is the maximum achievable processing thickness, t_min is the minimum achievable processing thickness; γ_max is the maximum value of the optimized design variable γ, and γ_min is the minimum value of the optimized design variable γ; The value of γ is between 0 - 1.0; when γ = 0, it represents a solid; when γ = 1.0, it represents a fluid, and when the value of γ is between 0 - 1.0, the medium is a porous material.

2. The TPMS topological optimization method for the bent cooling channel structure according to claim 1, characterized in that: the first channel (21) and the third channel (23) are respectively located on both sides of the second channel (22), a first partition (11) is arranged between the first channel (21) and the second channel (22), and a second partition (12) is arranged between the second channel (22) and the third channel (23).

3. The TPMS topological optimization method for the bent cooling channel structure according to claim 2, characterized in that: the first porous structure (41) is arranged on the inner side of the second channel (22) near the second partition (12), and the second porous structure (42) is arranged on the inner side of the third channel (23) near the second partition (12).

4. The TPMS topology optimization method for the bent cooling channel structure according to claim 2, characterized in that: the outer edge contour of the first porous structure (41) near the second channel (22) connecting one end of the first flow bend (31) is inclined towards the first partition (11); the outer edge contour of the first porous structure (41) near the second channel (22) connecting one end of the second flow bend (32) shrinks towards the second partition (12).

5. The TPMS topology optimization method for the bent cooling channel structure according to claim 2, characterized in that: the width of the second porous structure (42) is 0.05 - 0.2 times the width of the third channel (23), and the width of the second porous structure (42) extending towards the side of the third channel (23) away from the second flow bend (32) gradually decreases.

6. The TPMS topology optimization method for the bent cooling channel structure according to claim 1, characterized in that: the porosity of the first porous structure (41) and the second porous structure (42) is 50% - 95%, and the pores of the first porous structure (41) and the second porous structure (42) communicate with the outside in the transverse and longitudinal directions.

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