A high-power laser absorption device based on micro-channel array

Abstract

The application relates to a high-power laser absorption device based on a micro-flow channel array, which comprises an absorption cavity, a beam expander, a support base and a micro-flow channel array; the absorption cavity is in a cylindrical structure, a laser incidence port is arranged at the front end, an absorption cavity inner wall with a high absorption rate coating is arranged in the interior, and the absorption cavity inner wall is processed with a light extinction structure; the beam expander is installed at the rear end of the absorption cavity, and the side facing the interior of the absorption cavity is a reflective surface coated with a high reflectivity metal film layer; the micro-flow channel array is arranged in the wall of the absorption cavity and comprises a plurality of micro flow channels arranged in layers along the radial direction of the absorption cavity and extending in a spiral shape along the axial direction; each micro flow channel is arranged close to the absorption cavity inner wall, the two ends of the micro flow channel are respectively communicated with a water collecting cavity, and the water collecting cavity is connected with a first inlet joint and a first outlet joint. Compared with the prior art, the application improves the heat dissipation capacity, eliminates thermal stress and local overheating, has a very high laser absorption efficiency and a high structural integration degree.

Description

Technical Field

[0001] This invention relates to the field of high-power laser technology, and in particular to a high-power laser absorption device based on a microchannel array. Background Technology

[0002] The application of high-power laser technology in industrial manufacturing, national defense research, and medical surgery is becoming increasingly widespread, and the resulting laser safety issues are receiving more and more attention. In critical stages such as laser system debugging, optical path switching, or handling abnormal operating conditions, high-power laser beams must be safely absorbed to prevent irreversible damage to personnel, optical components, and surrounding equipment. As laser output power continues to climb to the kilowatt level and even higher, the heat flux density experienced by the absorption device increases exponentially, posing unprecedented challenges to its heat dissipation performance. When the laser power reaches the kilowatt level or higher, the heat flux density in a local area of ​​the absorption device can reach 10... 6 ~10 7 W / m 2 If such a high heat load cannot be discharged in time, it will quickly lead to a sharp rise in the temperature of the absorbing surface, causing coating ablation, thermal deformation of the substrate, or even structural failure.

[0003] Existing high-power laser absorption devices generally employ spiral or other single-channel cooling structures for thermal management. The basic principle of this traditional cooling method is to fabricate a meandering cooling channel within the absorption cavity wall, using forced convection of the cooling medium to remove heat. This technical solution is simple in structure and easy to implement, meeting basic heat dissipation requirements under low to medium power conditions. However, when faced with high-power lasers exceeding 10,000 watts, the inherent limitations of this traditional cooling structure become increasingly apparent, making it unsuitable for more demanding heat dissipation tasks.

[0004] First, the heat exchange area of ​​a single flow channel is very limited, making it difficult to cope with concentrated impacts of localized high heat flux densities. When the laser beam has uneven energy distribution or the spot shifts due to assembly errors, the temperature in the hot spot area will rise sharply, and the problem of localized overheating will be particularly prominent, seriously threatening the operational safety of the device.

[0005] Secondly, as the cooling medium flows along a single channel, its temperature gradually increases, resulting in a significant temperature gradient along the axis of the absorption chamber. This non-uniform temperature field can induce thermal stress concentration, which, under long-term cyclic action, may lead to structural fatigue or even cracking and failure, greatly shortening the service life of the device.

[0006] CN202410500698.7 discloses a laser collector including a reflective cone disposed within an absorber. The reflective cone has a reflective outer wall for reflecting laser light. A first cooling cavity is provided on the reflective cone for the flow of a cooling medium. The first cooling cavity includes an annular or spiral cavity located inside the reflective outer wall and extending continuously around the axis of the reflective outer wall, allowing the cooling medium to flow around the reflective outer wall. However, the interior of the reflective cone is a single annular / spiral cavity, resulting in insufficient heat dissipation capacity and upper limit of heat flux density. Furthermore, the reflective outer wall itself lacks microscale heat transfer enhancement structures. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art by providing a high-power laser absorption device based on a microchannel array, which improves heat dissipation, eliminates thermal stress and local overheating, and enhances reliability; has extremely high laser absorption efficiency, ensuring safety; and features high structural integration and fast response speed.

[0008] The objective of this invention can be achieved through the following technical solutions: This invention provides a high-power laser absorption device based on a microchannel array, comprising an absorption cavity, a beam expander cone, a support base, and a microchannel array; The absorption cavity is a cylindrical structure with a laser entrance at the front end and an inner wall with a high absorptivity coating. The inner wall of the absorption cavity is also processed with an extinction structure. The beam expander cone is installed at the rear end of the absorption cavity, and the side facing the inside of the absorption cavity is a reflective surface coated with a high-reflectivity metal film. The support base is fixed below the absorption cavity; The microchannel array is disposed within the wall of the absorption cavity, comprising multiple microchannels arranged radially in layers along the absorption cavity and extending spirally along the axial direction. Each microchannel is disposed close to the inner wall of the absorption cavity, and both ends of the microchannel are connected to the water collection cavity, which is externally connected to a first inlet connector and a first outlet connector.

[0009] Furthermore, the microchannels of the microchannel array are arranged in parallel. The cooling medium enters from the first inlet connector and is distributed to each microchannel through the water collection chamber. After heat exchange, it flows into the water collection chamber at the outlet end and out from the first outlet connector.

[0010] Furthermore, it also includes a conformal cooling channel, which is disposed on the back side of the beam expander cone, and the conformal cooling channel is externally connected to an independent second inlet connector and a second outlet connector.

[0011] Furthermore, the absorption cavity is made of high thermal conductivity oxygen-free copper and is integrally formed by 3D printing.

[0012] Furthermore, the outer diameter of the absorption cavity is 120mm, the inner diameter is 90mm, and the axial length is 160mm; the diameter of the laser entrance is 60mm.

[0013] Furthermore, the extinction structure of the inner wall of the absorption cavity is a continuous sawtooth shape with a tooth pitch of 1.5 mm and a tooth angle of 60°.

[0014] Furthermore, the high-absorption coating on the inner wall of the absorption cavity is a carbon-based coating, prepared using a magnetron sputtering process.

[0015] Furthermore, the beam expander cone is precision machined from oxygen-free copper, and the reflective surface is a composite curved surface with a central arc radius of curvature of 45mm and an outer cone angle of 25°, with a smooth transition between the two.

[0016] Furthermore, the high-reflectivity metal film layer of the beam expander cone is a gold film, prepared using an electroplating process.

[0017] Furthermore, the cross-section of the microchannel array is circular with a diameter of 1 mm, and the center distance between adjacent channels is 2 mm.

[0018] The equivalent diameter of the microchannels is in the microscale range, and the cooling medium is in a strongly turbulent state within the channels, with a convective heat transfer coefficient that is 5 to 10 times that of a traditional single-channel system. The total heat transfer area of ​​the microchannel array 4 is 3 to 20 times that of a traditional single-channel system of the same volume.

[0019] The working process of a high-power laser absorption device includes the following steps: S1. A high-power laser beam enters the absorption cavity from the laser entrance and irradiates the reflecting surface of the beam expander cone. The energy diffuses radially into a low-power-density beam, creating favorable conditions for subsequent efficient absorption. S2. The diffused laser beam is projected onto the extinction structure on the inner wall of the absorption cavity. After multiple reflections, it is absorbed by the high-absorptivity coating. During each reflection, some energy is absorbed by the high-absorptivity coating on the inner wall of the absorption cavity and converted into heat energy. After several reflections, the energy of the incident laser is completely captured and absorbed, with an overall absorption rate of over 99%. Only a very weak stray light may escape from the entrance, fully meeting the requirements for safe absorption of high-power lasers.

[0020] S3. Heat from the inner wall of the absorption chamber is rapidly transferred to the microchannel array through the oxygen-free copper substrate. The cooling medium enters from the first inlet connector and is evenly distributed to each microchannel via the water collection chamber. Inside the channels, forced convection heat transfer occurs between the cooling medium and the channel walls, carrying away the heat. Due to the large heat transfer area and extremely high convective heat transfer coefficient of the microchannel array, the axial temperature difference problem caused by the temperature rise of the cooling medium along the flow path in traditional single channels is effectively avoided, resulting in a uniform temperature distribution on the inner wall of the absorption chamber. The heated cooling medium collects from the ends of each channel into the water collection chamber at the outlet end and flows out through the first outlet connector into the external circulating cooling system. At the same time, a small amount of heat deposited on the beam expander cone is promptly carried away by the conformal cooling channel on its back side, protecting the reflective film from high-temperature damage.

[0021] Compared with the prior art, the present invention has the following advantages: (1) Improved heat dissipation capacity. By integrating a microchannel array within the wall of the absorption cavity, the cooling medium is made into a strongly turbulent state by utilizing the microscale effect, and the convective heat transfer coefficient reaches 5 to 10 times that of the traditional single channel. Compared with the traditional single spiral channel, the dense microchannel achieves a heat transfer area increase of several times to tens of times within a limited wall thickness, which is suitable for the stringent heat dissipation requirements of 10,000-watt lasers.

[0022] (2) Eliminate thermal stress and local overheating, and improve reliability. The microchannels are arranged in parallel, and the cooling medium enters each channel at the same time, which solves the problem of excessive axial temperature difference in the absorption cavity caused by the "temperature rise along the flow path" of the cooling medium in traditional single channels. The uniform temperature field reduces thermal stress concentration, avoids structural fatigue, cracking or deformation caused by long-term thermal cycling in traditional structures, and greatly extends the service life of the device.

[0023] (3) Extremely high laser absorption efficiency, ensuring safety. The designed composite curved beam expander cone evenly distributes the high-energy-density laser light in the center radially, reducing the power load per unit area. The inner wall of the absorption cavity is designed with a sawtooth extinction structure, combined with a carbon-based high-absorption coating, forcing the laser to undergo multiple reflections within the cavity. The overall laser absorption rate can reach over 99%, with only extremely weak stray light overflow, fully meeting the safety standards for high-power laser operation.

[0024] (4) High structural integration and fast response speed. The absorption cavity is integrally formed by 3D printing technology using high thermal conductivity oxygen-free copper material, which integrates the complex microchannel structure with the cavity, reducing assembly thermal resistance and improving overall thermal conductivity. In addition to the microchannel array of the main absorption cavity, a conformal cooling channel is also set for the beam expander cone, which realizes the precise and rapid removal of deposited heat and prevents the reflective film from being damaged by heat accumulation. Attached Figure Description

[0025] Figure 1This is a schematic cross-sectional view of a high-power laser absorption device based on a microchannel array. Figure 2 This is a partially enlarged schematic diagram of the microchannel array in a high-power laser absorption device based on a microchannel array. Figure 3 This is a flowchart illustrating the workflow of a high-power laser absorption device based on a microchannel array.

[0026] Reference numerals: 1. Absorption cavity; 2. Expanding cone; 3. Support base; 4. Microchannel array; 5. Conformal cooling channel; 6. First inlet connector; 7. First outlet connector; 8. Water collection cavity; 9. Second inlet connector; 10. Second outlet connector; 11. Inner wall of the absorption cavity. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0028] Example 1 This embodiment provides a high-power laser absorption device based on a microchannel array, such as... Figure 1 As shown, it includes an absorption cavity 1, a beam expander cone 2, a support base 3, and a microchannel array 4; The absorption cavity 1 is a cylindrical structure with a laser entrance port at the front end and an inner wall 11 with a high absorptivity coating inside. The inner wall 11 of the absorption cavity is processed with an extinction structure. The beam expander cone 2 is installed at the rear end of the absorption cavity 1, and the side facing the inside of the absorption cavity is a reflective surface coated with a high reflectivity metal film. The support base 3 is fixed below the absorption cavity 1; The microchannel array 4 is disposed in the wall of the absorption cavity 1, including multiple microchannels arranged in layers along the radial direction of the absorption cavity and extending in a spiral shape along the axial direction. Each microchannel is disposed close to the inner wall 11 of the absorption cavity. The two ends of the microchannel are respectively connected to the water collection cavity 8. The water collection cavity 8 is externally connected to the first inlet connector 6 and the first outlet connector 7.

[0029] Example 2 This embodiment provides a high-power laser absorption device based on a microchannel array, such as... Figure 1 , 2 As shown, it includes an absorption cavity 1, a beam expander cone 2, a support base 3, and a microchannel array 4; The absorption cavity 1 is a cylindrical structure with a laser entrance port at the front end and an inner wall 11 with a high absorptivity coating inside. The inner wall 11 of the absorption cavity is processed with an extinction structure. The beam expander cone 2 is installed at the rear end of the absorption cavity 1, and the side facing the inside of the absorption cavity is a reflective surface coated with a high reflectivity metal film. The support base 3 is fixed below the absorption cavity 1; The microchannel array 4 is disposed in the wall of the absorption cavity 1, including multiple microchannels arranged in layers along the radial direction of the absorption cavity and extending in a spiral shape along the axial direction. Each microchannel is disposed close to the inner wall 11 of the absorption cavity. The two ends of the microchannel are respectively connected to the water collection cavity 8. The water collection cavity 8 is externally connected to the first inlet connector 6 and the first outlet connector 7.

[0030] In a specific embodiment, the microchannels of the microchannel array 4 are arranged in parallel. The cooling medium enters from the first inlet connector 6 and is distributed to each microchannel through the water collection chamber 8. After heat exchange, it flows into the water collection chamber 8 at the outlet end and flows out from the first outlet connector 7.

[0031] In a specific embodiment, it also includes a conformal cooling channel 5, which is disposed on the back side of the expansion cone 2, and the conformal cooling channel 5 is externally connected to an independent second inlet connector 9 and a second outlet connector 10.

[0032] In a specific embodiment, the absorption cavity 1 is made of high thermal conductivity oxygen-free copper material and is integrally formed by 3D printing.

[0033] In a specific embodiment, the outer diameter of the absorption cavity 1 is 120mm, the inner diameter is 90mm, and the axial length is 160mm; the diameter of the laser entrance is 60mm.

[0034] In a specific embodiment, the extinction structure of the inner wall 11 of the absorption cavity is a continuous sawtooth shape with a tooth pitch of 1.5 mm and a tooth angle of 60°.

[0035] In a specific embodiment, the high-absorption coating on the inner wall 11 of the absorption cavity is a carbon-based coating, prepared by magnetron sputtering.

[0036] In a specific embodiment, the beam expander cone 2 is precision machined from oxygen-free copper material, the reflective surface is a composite curved surface, the central arc surface has a curvature radius of 45mm, the outer cone surface has a cone angle of 25°, and the two are smoothly transitioned.

[0037] In a specific embodiment, the high-reflectivity metal film layer of the beam expander cone 2 is a gold film, prepared using an electroplating process.

[0038] In a specific embodiment, the microchannel array 4 has a circular cross-section with a diameter of 1 mm and a center-to-center distance of 2 mm between adjacent channels. It contains a total of 9 microchannels.

[0039] The equivalent diameter of the microchannels is in the microscale range, and the cooling medium is in a strongly turbulent state within the channels, with a convective heat transfer coefficient that is 5 to 10 times that of a traditional single-channel system. The total heat transfer area of ​​the microchannel array 4 is 3 to 20 times that of a traditional single-channel system of the same volume.

[0040] like Figure 3 As shown, the working process of the high-power laser absorption device includes the following steps: S1. A high-power laser beam enters the absorption cavity 1 from the laser entrance port and irradiates the reflecting surface of the beam expander cone 2. The energy diffuses radially into a low-power density beam, creating favorable conditions for subsequent efficient absorption. S2. The diffused laser beam is projected onto the extinction structure of the inner wall 11 of the absorption cavity. After multiple reflections, it is absorbed by the high-absorptivity coating. During each reflection, some energy is absorbed by the high-absorptivity coating on the surface of the inner wall 11 of the absorption cavity and converted into heat energy. After several reflections, the energy of the incident laser is completely captured and absorbed, with an overall absorption rate of over 99%. Only a very weak stray light may escape from the entrance, fully meeting the requirements for safe absorption of high-power lasers.

[0041] S3. Heat from the inner wall 11 of the absorption chamber is rapidly transferred to the microchannel array 4 through the oxygen-free copper substrate. The cooling medium enters from the first inlet connector 6 and is evenly distributed to each microchannel via the water collection chamber 8. Inside the channel, forced convection heat transfer occurs between the cooling medium and the channel wall, carrying away the heat. Due to the large heat transfer area and extremely high convective heat transfer coefficient of the microchannel array, the axial temperature difference problem caused by the temperature rise of the cooling medium along the flow path in traditional single channels is effectively avoided, resulting in a uniform temperature distribution on the inner wall 11 of the absorption chamber. The heated cooling medium is collected from the ends of each channel to the water collection chamber 8 at the outlet end and flows out through the first outlet connector 7 into the external circulating cooling system. At the same time, a small amount of heat deposited on the beam expander cone 2 is promptly carried away by the conformal cooling channel 5 on its back side, protecting the reflective film from high-temperature damage.

[0042] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0043] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A high-power laser absorption device based on a microchannel array, characterized in that, It includes an absorption cavity (1), a beam expander cone (2), a support base (3), and a microchannel array (4); The absorption cavity (1) is a cylindrical structure with a laser inlet at the front end and an inner wall (11) with a high absorptivity coating inside. The inner wall (11) of the absorption cavity is processed with an extinction structure. The beam expander cone (2) is installed at the rear end of the absorption cavity (1), and the side facing the inside of the absorption cavity is a reflective surface coated with a high reflectivity metal film. The support base (3) is fixed below the absorption cavity (1); The microchannel array (4) is disposed in the wall of the absorption cavity (1), including multiple microchannels arranged in layers along the radial direction of the absorption cavity and extending in a spiral shape along the axial direction. Each microchannel is disposed close to the inner wall (11) of the absorption cavity. The two ends of the microchannel are connected to the water collection cavity (8) respectively. The water collection cavity (8) is externally connected to the first inlet connector (6) and the first outlet connector (7).

2. The high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The microchannel array (4) has each microchannel arranged in parallel. The cooling medium enters from the first inlet connector (6) and is distributed to each microchannel through the water collection chamber (8). After heat exchange, it flows into the water collection chamber (8) at the outlet end and flows out from the first outlet connector (7).

3. The high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, It also includes a conformal cooling channel (5), which is located on the back of the expansion cone (2), and the conformal cooling channel (5) is externally connected to an independent second inlet connector (9) and a second outlet connector (10).

4. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The absorption cavity (1) is made of high thermal conductivity oxygen-free copper material and is integrally formed by 3D printing.

5. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The absorption cavity (1) has an outer diameter of 120 mm, an inner diameter of 90 mm, and an axial length of 160 mm; the laser inlet has a diameter of 60 mm.

6. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The extinction structure of the inner wall (11) of the absorption cavity is a continuous sawtooth shape with a tooth pitch of 1.5 mm and a tooth angle of 60°.

7. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The high absorptivity coating on the inner wall (11) of the absorption cavity is a carbon-based coating, prepared by magnetron sputtering.

8. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The beam expander cone (2) is precision machined from oxygen-free copper material. The reflective surface is a composite curved surface with a central arc radius of curvature of 45mm and an outer cone angle of 25°.

9. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The high-reflectivity metal film layer of the beam expander cone (2) is a gold film.

10. A high-power laser absorption device based on a microchannel array according to claim 1, characterized in that, The microchannel array (4) has a circular cross-section with a diameter of 1 mm and a center-to-center distance of 2 mm between adjacent channels.

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