A laminated sheet sweating cooling structure

Abstract

The application discloses a laminated sheet sweating cooling structure which can be formed by a laser selective melting 3D printing technology and comprises a porous surface layer, a solid base plate and a connecting pipe nozzle; the solid base plate internally contains a working medium transport channel, and a working medium inlet is arranged at a bottom center position; an outer wall surface of the porous surface layer is a surface to be cooled, and an inner wall surface of the porous surface layer is in contact with the working medium; during operation, the cooling working medium enters the transport channel from the working medium inlet, reaches the porous surface layer at the end, and the cooling working medium seeps out to the outer wall surface through micropores in the porous surface layer; the connecting pipe nozzle is connected with the working medium inlet and is directly formed by the 3D printing or is fixedly connected with the solid base plate through welding. The application comprehensively designs and processes, and both working medium transport requirements and process powder cleaning requirements are met.

Description

Technical Field

[0001] This invention belongs to the field of active thermal protection design in the aerospace and aircraft / engine industries, and specifically relates to a stacked thin plate sweating cooling structure. Background Technology

[0002] Sweating cooling technology uses a pressurization device to transport liquid coolant to the high-heat areas, which then seeps out from a pre-placed porous layer to the outer wall surface. The liquid coolant absorbs a large amount of structural heat through phase change, and simultaneously, the vaporized coolant forms a gas film layer on the high-heat surface, effectively blocking direct heating of the structure by the high-temperature airflow, resulting in high cooling efficiency. Furthermore, sweating cooling also reduces surface aerodynamic drag and lowers surface infrared signature, and has become a key technology and primary method for active thermal protection of various high-speed aerospace vehicles and rocket engines.

[0003] Aircraft design typically pursues extreme lightweighting to achieve higher, faster, and farther speeds. Applying sweating cooling technology to large areas of aerospace vehicle bodies faces severe constraints related to thickness and weight. Furthermore, the engineering application of large-area sweating cooling necessitates solving the problem of uniform distribution and supply of the working fluid; otherwise, poor transport of the cooling working fluid in some areas can easily lead to localized high temperatures, resulting in "heat transfer deterioration." Therefore, porous sweating structures in thin-walled components must achieve large-area uniformity and synchronous supply of the working fluid within a limited thickness.

[0004] In addition to the feasibility of the principle, the feasibility of the manufacturing process must also be considered for sweating and cooling structures. Currently, the processes for fabricating microporous metal components for permeation and sweating generally include screen sintering and 3D printing. Compared with sintering, 3D printing can achieve integrated molding of porous and solid regions, and the internal transport channels of the structure are highly designable. Among these, selective laser melting (SLM) 3D printing technology has significant advantages such as high molding accuracy, precise control of microstructure, and near-net-shape forming, making it the preferred process for porous sweating structures. However, after the structure is formed, the internal channels are filled with metal powder, which must be removed promptly. The ease of powder removal should also be considered in the structural design to avoid cavitation and other problems.

[0005] The challenge in designing a sweating cooling structure for thin-walled plates lies in comprehensively considering both the requirements for working fluid transport and the process cleaning requirements. Currently, there are no publicly available literature reports on sweating cooling structures for thin-walled components. Summary of the Invention

[0006] To address the aforementioned issues, this invention proposes a stacked thin-plate sweating cooling structure adapted to laser selective melting 3D printing technology. Through the stacking and array design of inverted-bucket-shaped liquid accumulation units of different sizes, it achieves large-area synchronous and uniform supply of the working fluid within a relatively thin thickness, while also facilitating powder removal after 3D printing. The liquid accumulation chamber structure also serves to resist thermal shock and short-term high overload, and adapt to changes in different curved surface shapes.

[0007] A layered thin-plate sweating cooling structure includes a porous surface layer, a solid substrate, and a connecting nozzle. The solid substrate contains a working fluid transport channel, with a working fluid inlet at the bottom center. The outer wall of the porous surface layer is the surface to be cooled, and the inner wall is in contact with the working fluid. During operation, the cooling working fluid enters the transport channel through the working fluid inlet, reaches the porous surface layer at the end, and then seeps out to the outer wall through the micropores inside the porous surface layer. The connecting nozzle is connected to the working fluid inlet and is directly formed by 3D printing or fixed to the solid substrate by welding.

[0008] The transport channel is composed of four stacked liquid accumulation chambers. The first-level liquid accumulation chamber is connected to the working fluid inlet, followed by the second-level, third-level, and fourth-level liquid accumulation chambers. Each level of liquid accumulation chamber contains units with the same structure, and each unit is inverted funnel-shaped. From the first-level liquid accumulation chamber to the fourth-level liquid accumulation chamber, the level decreases, and the number of inverted funnel-shaped units increases in multiples of four, while the volume of the inverted funnel-shaped units decreases synchronously.

[0009] Furthermore, for a flat thin-walled component with a planar dimension of 100mm×100mm, the first-level liquid accumulation chamber contains one inverted funnel-shaped unit with a thickness of 2.5mm; the second-level liquid accumulation chamber contains four inverted funnel-shaped units with a thickness of 2mm; the third-level liquid accumulation chamber contains 16 inverted funnel-shaped units with a thickness of 1.5mm; and the fourth-level liquid accumulation chamber contains 64 inverted funnel-shaped units with a thickness of 1.5mm. The total thickness of the transport channels is 7.5mm, the thickness of the solid substrate is 1.5mm, and with the 7.5mm thick transport channels and the 1mm thick porous surface layer, the total thickness of the entire thin-walled component is 10mm.

[0010] Furthermore, the small ridge planes of the secondary liquid accumulation chamber are located at the four corner points of the inverted funnel-shaped unit of the primary liquid accumulation chamber, arranged symmetrically. Similarly, the structure is consistent from the secondary liquid accumulation chamber to the tertiary liquid accumulation chamber, and from the tertiary liquid accumulation chamber to the quaternary liquid accumulation chamber. When the cooling working fluid enters the four inverted funnel-shaped units of the secondary liquid accumulation chamber from the primary liquid accumulation chamber through the four corner points, the flow resistance is the same, and the working fluid will be evenly divided into four parts, which will enter the four inverted funnel-shaped units respectively. By analogy, the final path of the working fluid from the working fluid inlet 5 to any one of the inverted funnel-shaped units of the quaternary liquid accumulation chamber is completely equal, and the flow resistance is also completely consistent.

[0011] Furthermore, the 64 inverted bucket-shaped units of the four-stage liquid accumulation chamber are evenly arranged in an array, with a spacing width of 1mm between adjacent inverted bucket-shaped units, a planar dimension of 11.5mm×11.5mm for a single inverted bucket-shaped unit, and a small bottom planar dimension of 2mm×2mm.

[0012] Furthermore, each of the inverted bucket-shaped units has a pre-set discharge angle of 17.5°.

[0013] Furthermore, it is formed using laser selective melting 3D printing technology.

[0014] The beneficial effects of this invention are as follows:

[0015] (1) The stacked liquid accumulation chamber structure can achieve uniform and synchronous supply of cooling working fluid in a large area within a thickness of 10mm, effectively avoiding heat transfer deterioration caused by poor local cooling working fluid transport.

[0016] (2) The inverted bucket-shaped unit has a pre-set discharge angle for metal powder, which solves the problem of powder cleaning after thin-walled components with complex internal flow channels are formed by laser selective melting 3D printing technology;

[0017] (3) The presence of the inverted bucket-shaped unit ensures that the working fluid is always filled with the liquid accumulation cavity, which can resist the instantaneous thermal load impact caused by sudden changes in flight attitude, and enhance the thermal environment adaptability of the sweating cooling structure.

[0018] (4) The inlet of the folded bucket-shaped unit is smaller and the resistance to the backflow of the working medium is larger. This can avoid the impact of pressure fluctuations in a single area on the working medium supply of other units, resist short-term large overloads to a certain extent, and make the sweating structure more adaptable to curved shapes, thus improving the value of engineering applications.

[0019] (6) Thin-walled components can be used as standardized assembly modules. They can be designed and assembled in batches according to their actual shape and area, and then inlaid and spliced ​​together to form a large-area sweating and cooling structure, which is highly practical. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a stacked thin-plate sweating and cooling structure.

[0021] Figure 2 This is a schematic diagram of the transport cavity structure;

[0022] Figure 3 This is a schematic diagram of an inverted bucket-shaped unit structure;

[0023] in,

[0024] 1-Porous surface layer 2-Solid substrate 3-Nozzle 4-Transport channel 5-Working fluid inlet 6-Primary fluid collection chamber 7-Secondary fluid collection chamber 8-Tertiary fluid collection chamber 9-Fourth-stage fluid collection chamber 10-Unit 11-Tilt angle Detailed Implementation

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection claimed by the present invention.

[0026] A layered thin-plate sweating cooling structure, such as Figure 1 As shown, it consists of three parts: a porous surface layer 1, a solid substrate 2, and a nozzle 3. The outer wall of the porous surface layer 1 is the surface to be cooled, directly bearing the high heat load, while the inner wall is in contact with the working fluid. During operation, driven by the pressure of the supply system, the cooling working fluid seeps out through the micropores inside the porous surface layer 1 to the outer wall, achieving the effect of sweating and cooling. The porous surface layer 1 has a thickness of 1 mm. The solid substrate 2 is a load-bearing structure of a large-area thin-walled component, and also contains a working fluid transport channel 4 inside. A working fluid inlet 5 is opened at the center of the bottom. During operation, the cooling working fluid enters the transport channel 4 through the working fluid inlet 5 and finally reaches the porous surface layer 1 at the end. The nozzle 3 is connected to the working fluid inlet 5 and can be directly formed by 3D printing or fixed to the solid substrate 2 by welding.

[0027] like Figure 2 , Figure 3 As shown, the transport cavity 4 is composed of four stacked liquid accumulation chambers. The first-level liquid accumulation chamber 6 is connected to the working medium inlet 5, followed by the second-level liquid accumulation chamber 7, the third-level liquid accumulation chamber 8, and the fourth-level liquid accumulation chamber 9. Each level of liquid accumulation chamber contains several units 10 with the same structure, and each unit 10 is inverted funnel-shaped. From the first level to the fourth level, the level of liquid accumulation chamber decreases, the number of inverted funnel-shaped units 10 increases in multiples of four, and the volume of unit 10 decreases synchronously.

[0028] Specifically, for a flat, thin-walled component with a planar dimension of 100mm × 100mm, the primary liquid accumulation chamber 6 contains one inverted funnel-shaped unit 10 with a thickness of 2.5mm; the secondary liquid accumulation chamber 7 contains four inverted funnel-shaped units 10 with a thickness of 2mm; the tertiary liquid accumulation chamber 8 contains 16 inverted funnel-shaped units 10 with a thickness of 1.5mm; the quaternary liquid accumulation chamber 9 contains 64 inverted funnel-shaped units 10 with a thickness of 1.5mm; and the total thickness of the transport channel 4 is 7.5mm. At the working fluid inlet 5, the thickness of the solid substrate 2 is 1.5mm, and with the 7.5mm thick transport channel 4 and the 1mm thick porous surface layer 1, the total thickness of the entire thin-walled component is 10mm.

[0029] For the fourth-level liquid accumulation chamber 9, 64 inverted bucket-shaped units 10 are evenly arranged in an array. The spacing between adjacent inverted bucket-shaped units 10 is 1 mm. The planar dimensions of a single inverted bucket-shaped unit 10 are 11.5 mm × 11.5 mm, the small bottom plane dimensions are 2 mm × 2 mm, and the inclination angle 11 in the thickness direction is 17.5°.

[0030] The four inverted-funnel units 10 of the secondary liquid collection chamber 7 have their small ridges located at the four corner points of the inverted-funnel unit 10 of the primary liquid collection chamber 6, arranged symmetrically. Similarly, the structure is identical from the secondary liquid collection chamber 7 to the tertiary liquid collection chamber 8, and from the tertiary liquid collection chamber 8 to the quaternary liquid collection chamber 9. Therefore, when the cooling working fluid enters the four inverted-funnel units 10 of the secondary liquid collection chamber 7 from the primary liquid collection chamber 6 through the four corner points, the flow resistance is the same, and the working fluid will be evenly divided into four parts, entering the four inverted-funnel units 10 respectively. Following this pattern, the final path of the working fluid from the working fluid inlet 5 to any one of the inverted-funnel units 10 of the quaternary liquid collection chamber 9 is completely equal, and the flow resistance is also completely consistent. Therefore, the 64 inverted-funnel units 10 of the quaternary liquid collection chamber 9 will receive the same working fluid flow rate. This structure can achieve uniform and synchronous supply of working fluid over a large area within a total thickness of 10 mm.

[0031] The inverted bucket-shaped unit 10 has a pre-set powder discharge angle of 11. After forming a thin plate sweating and cooling structure through laser selective melting 3D printing technology, the porous layer only needs to be horizontally facing upwards, and with the assistance of external vibration, the metal powder can flow out naturally under the action of gravity. There are no dead corners to clean, and the operation is convenient.

[0032] When the layered thin-plate sweating cooling structure is applied to large areas of an aircraft, the presence of the inverted bucket-shaped unit 10 ensures that the working fluid is always filled with liquid, which can resist the instantaneous thermal load impact caused by sudden changes in flight attitude, play a certain buffering role, and enhance the thermal environment adaptability of the sweating cooling structure.

[0033] The inlet of the truncated bucket-shaped unit 10 is relatively small, resulting in greater resistance to the backflow of the working fluid. Therefore, if a momentary pressure increase occurs in one of the 64 truncated bucket-shaped units 10, the disturbance to the working fluid supply of the remaining units 10 is relatively small, which can resist short-term large overloads to a certain extent. Furthermore, this characteristic is not limited to flat plates and has strong adaptability to the curved shapes of thin-walled components, enhancing the value of the sweating structure in engineering applications.

[0034] The aforementioned 100mm×100mm thin-walled components can serve as standardized assembly modules, facilitating generalized design and mass assembly based on actual shape and area. Ultimately, they can be inlaid and spliced ​​together to form a large-area sweating and cooling structure, which has strong practical value.

[0035] This invention is not limited to the above-described structural method. Regardless of any changes made to its shape or structure, any molded integral heat insulation layer structure established using this invention falls within the protection scope of this invention.

Claims

1. A laminated sheet sweating cooling structure characterized by, The porous surface layer, the solid substrate and the connecting pipe nozzle are included; the solid substrate contains the transport cavity of working medium inside, and the working medium inlet is arranged at the bottom center position; the outer wall surface of the porous surface layer is the surface to be cooled, and the inner wall surface is in contact with the working medium; during operation, the cooling working medium enters the transport cavity from the working medium inlet, reaches the porous surface layer at the end, and the cooling working medium seeps out to the outer wall surface through the micropores inside the porous surface layer; the connecting pipe nozzle is connected with the working medium inlet and is directly formed by 3D printing or is fixedly connected with the solid substrate by welding; The transport cavity is composed of four-stage liquid accumulation cavity laminates, and the first-stage liquid accumulation cavity is connected with the working medium inlet; the second-stage liquid accumulation cavity, the third-stage liquid accumulation cavity and the fourth-stage liquid accumulation cavity are sequentially arranged upwards; Each stage liquid accumulation cavity includes units with the same structure, and each unit is in the form of a bucket; from the first-stage liquid accumulation cavity to the fourth-stage liquid accumulation cavity, the stage is sequentially lowered, the number of bucket units included is increased by four times, and the volume of the bucket unit is simultaneously reduced. The bucket unit is preset with a discharge inclination angle of 17.5°.

2. The laminated sheet sweating cooling structure according to claim 1, wherein For a flat thin-walled component with a plane size of 100mm*100mm, the first-stage liquid accumulation cavity includes one bucket unit, and the thickness is 2.5mm; the second-stage liquid accumulation cavity includes four bucket units, and the thickness is 2mm; the third-stage liquid accumulation cavity includes sixteen bucket units, and the thickness is 1.5mm; the fourth-stage liquid accumulation cavity includes sixty-four bucket units, and the thickness is 1.5mm; the total thickness of the transport cavity is 7.5mm, the thickness of the solid substrate is 1.5mm, and the total thickness of the whole thin-walled component is 10mm after adding the 7.5mm-thick transport cavity and the 1mm-thick porous surface layer.

3. The laminated sheet sweating cooling structure according to claim 2, wherein The small bottom planes of the second-stage liquid accumulation cavity are symmetrically arranged at four corner points of the bucket unit of the first-stage liquid accumulation cavity; similarly, the structures are consistent from the second-stage liquid accumulation cavity to the third-stage liquid accumulation cavity and from the third-stage liquid accumulation cavity to the fourth-stage liquid accumulation cavity; When the cooling working medium enters the four bucket units of the second-stage liquid accumulation cavity from the four corner points of the first-stage liquid accumulation cavity, the flow resistance is the same, the working medium is evenly divided into four parts, and the four parts enter the four bucket units respectively; by analogy, the path of the working medium from the working medium inlet (5) to the bucket unit of any fourth-stage liquid accumulation cavity is completely equal, and the flow resistance is completely consistent.

4. The laminated sheet sweating cooling structure according to claim 3, wherein The sixty-four bucket units of the fourth-stage liquid accumulation cavity are arranged in an array, the spacing width between adjacent bucket units is 1mm, and the plane size of a single bucket unit is 11.5mm*11.5mm, and the size of the small bottom plane is 2mm*2mm.

5. The laminated sheet sweating cooling structure according to claim 4, wherein The 3D printing technology is formed by laser selective melting.

Images