Cascade variable voltage micro-channel heat dissipation structure and high-power laser cutoff diaphragm

Abstract

The application discloses a step variable pressure type micro-channel heat dissipation structure and a high-power laser cut-off light screen, and the structure comprises a flow channel (3), a gradually widened micro-channel (4), a first step variable pressure structure (5) and a second step variable pressure structure (6). The first step variable pressure structure (5) and the second step variable pressure structure (6) comprise a plurality of step-by-step increased elliptical cylinder arrays, the number of the elliptical cylinders is step-by-step increased, the length of the short axis of the elliptical cylinder is step-by-step decreased, the fluid flow cross-sectional area is step-by-step decreased, and the flow speed is step-by-step increased to form a jet effect to accelerate the fluid, and finally the fluid enters the gradually widened micro-channel (4) at a higher flow speed to realize flow heat exchange. The step variable pressure structure with the step-by-step increased number of elliptical cylinders, the step-by-step decreased length of the short axis and the step-by-step decreased total flow cross-sectional area at the micro-channel inlet section can rapidly and gradiently increase the pressure to accelerate the fluid, and effectively solve the problems of excessive and concentrated pressure at the micro-channel inlet.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser equipment, and more particularly to a stepped variable pressure micro-channel heat dissipation structure and a high-power laser cutoff diaphragm with the same. BACKGROUND

[0002] In a high-power laser, the diaphragm is an entity that limits the light beam, and its function is to intercept unnecessary stray light through a specific size of the light beam. When a kilowatt-level laser beam passes through the diaphragm hole, the laser power intercepted by the diaphragm is considerable, and the extremely high power density distribution around the diaphragm hole will cause overheating, resulting in local air turbulence and affecting the beam quality. In the past, the heat dissipation design of the diaphragm uses a fluid flowing through a macro-channel to absorb heat, which has an upper limit of heat absorption capacity and cannot cope with the temperature rise problem caused by excessively high power density. Micro-channel heat exchange is a new type of heat exchange structure that uses micron-scale channels for flow heat exchange. The channel size is usually 10 microns to 1 millimeter, and the flow state in the channel is extremely stable, and the heat exchange efficiency is very considerable. It has a series of advantages such as compact structure, high efficiency, energy saving, light and convenient, long service life, and strong adaptability. It has a wide range of applications in microelectronic devices, aerospace efficient heat dissipation, automobile air conditioning system heat exchange and other fields.

[0003] Therefore, designing a micro-channel heat dissipation flow channel can effectively meet the demand for efficient heat dissipation of the cutoff diaphragm. At present, the existing similar micro-channel design for heat dissipation of the diaphragm of a high-power laser does not solve the above-mentioned problems of excessive pressure, redundant flow, uneven flow channel size, and kinetic energy loss. The patent "Embedded adjustable high-heat-dissipation-performance laser cutoff diaphragm" designs an additional diaphragm base and designs a horizontal micro-channel inside the base to dissipate heat from the diaphragm. On the one hand, the large-area micro-channel causes a large along-path resistance, and the inlet pressure concentration problem is not solved; on the other hand, the patent does not consider the power density distribution of stray light in the basic conditions of heat design. In the actual heat exchange process, only a part of the micro-channel structure plays a heat exchange role in the large-area spread of the micro-channel.

[0004] But through simulation of the heat dissipation process, it is found that there are the following problems in designing a micro-channel structure in a larger size diaphragm: (1) the local pressure at the inlet section is too high Figure 4(2) The excessive resistance at the entrance of the aperture branch forces the fluid to enter other branches, affecting the flow distribution of other branches and thus affecting the normal working state; (3) In a large-size aperture, the flow resistance caused by the micro-channel structure is huge, and the flow and heat exchange capacity of the fluid in the rear section of the micro-channel is attenuated, which is not conducive to ensuring its heat dissipation performance; (4) The stray light power density distribution is non-uniform and decreases in gradient, and the size of the micro-channel should also be adjusted according to the actual conditions. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a stepped pressure type micro-channel heat dissipation structure and a high-power laser cutoff aperture. The flow of fluid is controlled by a flow valve before entering the flow passage, and the local pressure concentration problem at the entrance section is considered. The fluid will pass through the stepped pressure increasing structure to disperse the excessively concentrated pressure at the local entrance section into a stepped pressure increasing distribution form, thereby avoiding the possibility of flow instability caused by excessive local pressure at the entrance of the micro-channel. After the fluid is pressurized, it can enter the micro-channel at a faster flow rate to enhance heat exchange. At the same time, according to the power density distribution of stray light around the aperture hole, the size of the micro-channel is designed to increase in size gradient outward from the aperture hole, which can meet the heat dissipation requirements while relieving the flow resistance in the flow passage.

[0006] To achieve the above-mentioned purpose, according to the first aspect of the present application, a stepped pressure type micro-channel heat dissipation structure is provided, comprising a flow passage, a gradually widened micro-channel arranged in the flow passage, and a first stepped pressure structure arranged at the entrance of the gradually widened micro-channel, and a second stepped pressure structure arranged at the outlet of the gradually widened micro-channel.

[0007] The first stepped pressure structure and the second stepped pressure structure comprise a plurality of elliptical column arrays, the number of the elliptical columns increases gradually, the length of the short axis of the elliptical column decreases gradually, and the flow area decreases gradually. When the fluid flows through the elliptical column, the local flow pressure increases due to the narrowing of the channel size, the flow velocity increases to form a jet effect to accelerate the fluid. Each time the fluid passes through the narrowest flow area between the elliptical columns, the pressure increases and the jet effect is enhanced. With the gradual increase of the elliptical columns, the total flow area of each level decreases in turn, forming greater pressure increase and flow velocity increase. Finally, the fluid enters the gradually widened micro-channel at a higher flow rate to realize flow and heat exchange.

[0008] Further, a turbulence array is arranged between the first and second step pressure structures and the entrance of the gradually-widening microchannel to balance the influence of flow at different positions.

[0009] Further, the first and second step pressure structures adopt an elliptical column structure with a streamlined shape.

[0010] Further, the first and second step pressure structures adopt one of a triangular column, a polygonal column or a cylindrical column.

[0011] Further, the first and second step pressure structures, the turbulence array and the gradually-widening microchannel are designed according to the specific power distribution and flow channel pressure distribution.

[0012] Further, the gradually-widening microchannel adopts a gradually-widening size design to match the heat dissipation requirement of different power distributions.

[0013] Further, the gradually-widening microchannel is locally applied with step pressure increasing / decreasing structures.

[0014] Further, the gradually-widening microchannels are connected in series and parallel to make the fluid impact and stir.

[0015] Further, along the direction of increasing radius outward from the aperture hole, the design size of the gradually-widening microchannel is sequentially increased.

[0016] Further, the gradually-widening microchannel is processed in multiple segments, and multiple step pressure structures are arranged in adjacent segment microchannels to re-pressurize and accelerate the fluid to strengthen the fluidity.

[0017] Further, the flow channel further includes an entrance and exit arranged at the end of the flow channel.

[0018] Further, the flow channel further includes a flow valve arranged at the end of the flow channel.

[0019] The flow valve is used for feedback and adjustment of the flow of the aperture branch, so as to timely control the flow through the aperture branch.

[0020] According to a second aspect of the present application, a high-power laser cutoff aperture is provided, including an aperture plate and a step pressure type microchannel heat dissipation structure arranged on the aperture plate.

[0021] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects compared with the prior art:

[0022] 1. The structure of the present application, the flow of fluid is controlled by the flow valve before entering the flow channel, considering the local pressure concentration problem of the inlet section, the fluid will pass through the stepped booster structure, and the excessively concentrated pressure in the local inlet section will be dispersed into a stepped booster distribution form, thereby avoiding the possibility of flow instability caused by excessive local pressure in the microchannel inlet. The fluid after boosting can enter the microchannel at a faster flow rate to achieve the purpose of enhancing heat exchange. At the same time, according to the power density distribution of stray light around the aperture hole, the size of the microchannel is designed to be gradient increasing along the aperture hole, which can meet the heat dissipation requirements while relieving the flow resistance in the flow channel.

[0023] 2. The structure of the present application, by designing multiple passive stepped pressure change structures in the microchannel, the purpose of boosting the flow rate is achieved. On the one hand, the stepped pressure change structure can re-accelerate fluid flow to ensure heat exchange performance. On the other hand, the simple passive pressure change design avoids the rapid increase of processing cost and time caused by the complexity of the flow channel structure.

[0024] 3. The structure of the present application, the stepped pressure change structure of the elliptical cylinder with the number of steps increasing, the length of the short axis decreasing, and the total flow cross section decreasing, can rapidly gradient boost the fluid, effectively solving the problem of excessive and concentrated pressure at the microchannel inlet.

[0025] 4. The structure of the present application, the power distribution on the diaphragm is gradient decreasing from the hole edge to the surrounding, and the size of the microchannel is designed to be gradient increasing along the hole edge, which effectively meets the heat dissipation requirements while greatly relieving the flow resistance.

[0026] 5. The structure of the present application, the end of the stepped pressure boosting structure is provided with a row of cylindrical bodies, which can further disturb the high-speed fluid to strengthen its heat exchange performance and provide guarantee for the heat exchange of the fluid entering the microchannel.

[0027] 6. The structure of the present application, the multi-section microchannel design is applied in the heat dissipation flow channel of a larger size diaphragm, and the stepped pressure boosting / dropping structure is arranged between adjacent microchannels, which can effectively boost the fluid flow rate and ensure the flow characteristics and heat exchange performance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the diaphragm model in the embodiment of the present application;

[0029] Figure 2 The figure is a schematic diagram of the microchannel gradient pressure boosting structure model in the embodiment of the present application;

[0030] Figure 3 The figure is a schematic diagram of the two-section microchannel and two stepped structures in the embodiment of the present application;

[0031] Figure 4 The figure is the original microchannel pressure distribution in the embodiment of the present application;

[0032] Figure 5 Pressure distribution in the passage with gradient pressure increasing structure added to the embodiment of the present application;

[0033] Figure 6 In the temperature comparison results of the macro passage and the micro passage in the embodiment of the present application, 6(a) is the simulation result of the macro passage, and 6(b) is the simulation result of the micro passage.

[0034] In all the drawings, the same reference signs represent the same technical features, specifically: 1 - diaphragm plate, 2 - passage entrance and exit, 3 - flow channel, 4 - gradually widened micro passage, 5 - first gradient pressure increasing structure, 6 - second gradient pressure increasing structure, and 7 - flow valve. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present application clearer and more comprehensible, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0036] Embodiment 1

[0037] As Figure 4 shown is the original micro passage pressure distribution, through simulation analysis, it is found that at the flow channel entrance in Figure 4 , the front end pressure of the micro passage is large and concentrated. In order to solve the above problem, as Figures 1-3As shown, the embodiment of the present application provides a step variable pressure type micro-channel heat dissipation structure, which comprises a flow channel 3, a gradually widened micro-channel 4 arranged in the flow channel 3, a first step variable pressure structure 5 arranged at the inlet of the gradually widened micro-channel 4, and a second step variable pressure structure 6 arranged at the outlet of the gradually widened micro-channel 4; the first step variable pressure structure 5 and the second step variable pressure structure 6 comprise a plurality of step-by-step increased elliptical cylinder arrays, the number of the elliptical cylinders is step-by-step increased, the length of the minor axis of the elliptical cylinder is step-by-step decreased, and the fluid flow cross-sectional area is step-by-step decreased; when the fluid flows through the elliptical cylinder, the local flow pressure is increased due to the narrowing of the channel size, the flow velocity is increased to form a jet effect to accelerate the fluid, and the pressure is increased and the jet is enhanced every time the fluid flows through the narrowest flow cross-sectional area between the elliptical cylinders, and with the step-by-step increase of the elliptical cylinders, the total flow cross-sectional area of each step is sequentially decreased to form greater pressure increase and flow velocity increase, and finally the fluid enters the gradually widened micro-channel 4 to realize flow heat exchange at a higher flow velocity, the excessively concentrated pressure at the inlet section is divided into a gradient increased pressure distribution form, thereby solving the problems of flow redundancy, excessive and concentrated local pressure at the inlet section. The structure of the present application controls the flow by the flow valve before the fluid enters the flow channel, considers the local pressure concentration problem at the inlet section, and disperses the excessively concentrated pressure at the inlet section into a step-by-step pressure increase distribution form through the step-by-step pressure increase structure, thereby avoiding the possibility of flow instability caused by excessive local pressure at the inlet of the micro-channel. After the fluid is pressurized, it can enter the micro-channel at a faster flow velocity to achieve the purpose of enhancing heat exchange. At the same time, according to the power density distribution of stray light around the aperture hole, the size of the micro-channel is designed to be step-by-step increased along the aperture hole outward, which can meet the heat dissipation requirement while relieving the flow resistance in the flow channel.

[0038] Further, the flow valve performs macroscopic regulation and control of the aperture branch flow when the fluid flows into the micro-channel, and after the step-by-step pressure increase structure, the fluid rapidly pressurizes and accelerates to enter the micro-channel, thereby avoiding the problems of flow redundancy, excessive and concentrated pressure at the inlet of the micro-channel. Since the stray light power distribution is step-by-step decreased from the hole edge outward, the size of the micro-channel is designed to be step-by-step increased along the outward direction of the aperture hole radius, which can meet the heat dissipation requirement while relieving the flow resistance. When the aperture size is large, by designing a multi-section micro-channel, a plurality of step-by-step pressure increase and acceleration structures are arranged between adjacent micro-channels, which can ensure that the flow characteristics of the fluid in the flow channel are always observable, and the heat exchange performance of the entire micro-channel heat exchange system is also guaranteed.

[0039] In order to achieve the purpose of pressure boosting acceleration, the elliptical cylinder with streamlined form is used as the structure of gradient pressure boosting instead of other forms such as heat exchange fins, concave-convex structure and the like as the structure of pressure boosting acceleration, aiming at considering the pressure boosting acceleration while minimizing the kinetic energy loss or even backflow caused by the impact of fluid on local structure. At the end of the gradient pressure boosting structure, the fluid passes through the cylindrical spoiler column before entering the microchannel. The spoiler column is located at the front end of the microchannel entrance. Its role is to disturb and stir the fluid entering the microchannel again and to distribute the flow rate. Specifically, the first gradient pressure boosting structure 5 and the second gradient pressure boosting structure 6 adopt the structure of elliptical cylinder with streamlined form. Alternatively, one of the structure forms of triangular cylinder, polygonal cylinder or cylinder structure with gradually widening shape is adopted. The fluid flows through the flow valve into the heat dissipation flow channel, and the pressure rapidly rises after passing through the gradient pressure boosting structure. The fluid flows at a high speed, and can enter the microchannel with greater kinetic energy to improve the heat exchange performance. When the aperture size is large, the microchannel can be designed in segments and multiple stages of pressure boosting / decreasing structures can be arranged therein, which can effectively boost the flow speed and ensure the considerable heat dissipation performance.

[0040] The power density of stray light near the aperture hole shows a gradient decreasing distribution trend, so the heat dissipation capacity of the microchannel is not consistent at different radius positions. If all the microchannels adopt the same size, there will be a problem that the additional heat dissipation performance cannot be exerted and will further increase the resistance. Therefore, along the direction of increasing radius of the aperture hole, the design size of the microchannel should be increased in turn to reduce the resistance in the flow process while ensuring the heat exchange performance. Specifically, the first gradient pressure boosting structure 5, the second gradient pressure boosting structure 6, the spoiler array and the gradually widening microchannel 4 are designed according to the specific power distribution and flow channel pressure distribution. The gradually widening microchannel 4 adopts gradually widening size design to match the heat dissipation demand of different power distribution, and local gradient pressure boosting / decreasing structures are arranged, or the gradually widening microchannels 4 are connected in series and parallel, so that the fluid impact and stirring can also achieve similar effects. In addition, the gradually widening microchannel 4 is processed in multiple segments, and multiple gradient pressure boosting structures are arranged between adjacent segment microchannels to re-boost and accelerate the fluid to strengthen the flowability.

[0041] In addition, a spoiler array is arranged between the outlets of the first gradient pressure boosting structure 5 and the second gradient pressure boosting structure 6 and the inlet of the gradually widening microchannel 4 to balance the influence of flow at different positions. In addition, in the microchannel structure, there is usually a huge flow resistance. Therefore, the microchannel needs to be processed in multiple segments, and multiple gradient pressure boosting structures are arranged between adjacent segment microchannels to re-boost and accelerate the fluid to strengthen the flowability, and the flow heat exchange is continued when entering the next stage of microchannel again.

[0042] Further, the structure further comprises a channel inlet 2 arranged at the end of the flow channel 3, and a flow valve 7 arranged at the end of the flow channel 3; the flow valve 7 is used for feedback and adjustment of the flow of the aperture branch, so as to control the flow through the aperture branch in time, avoid the sudden increase of the local pressure of the microchannel due to the excessive inlet flow, and belong to the macro flow adjustment means of the inlet section.

[0043] In order to verify the heat dissipation performance of the structure designed in the application, simulation analysis is carried out, and the results are shown in Figure 5 and Figure 6 It can be clearly seen from the analysis of the data shown in the figure that the microchannel structure of the present application has obvious advantages in optimizing the pressure distribution and heat dissipation performance. Specifically, the maximum static pressure at the inlet of the microchannel is about 2.49×10 4 Pa, and the minimum value is close to-6.84×10 2 Pa, and the overall pressure increases gradually along the microchannel. This result shows that through the step-by-step pressurization process, the microchannel can effectively avoid the local pressure concentration problem commonly seen in traditional designs, ensuring the uniformity of the internal pressure distribution, thereby enhancing the flow stability. This uniform pressure distribution characteristic significantly reduces the risk of structural stress concentration and equipment performance degradation caused by pressure fluctuations. Combined with the power distribution characteristics of the aperture, it is found that the power density is mainly concentrated near the hole edge and decreases gradually with the increase of the distance. To adapt to this feature, the microchannel is designed to gradually increase in size along the hole edge. This gradually widening design not only effectively conducts and diffuses the heat in the high power density area, but also significantly relieves the resistance in fluid flow. Compared with the traditional non-gradually widening microchannel, the gradually widening microchannel optimizes the kinetic energy loss of the internal fluid, effectively improving the overall thermal management performance of the system. Figure 5 The smooth static pressure distribution gradient shown in the figure further verifies the improvement of the uniformity of the pressure distribution. This characteristic is particularly important for high-efficiency heat dissipation equipment, as uniform pressure distribution not only avoids the stagnation of fluid in local areas, but also ensures the effective diffusion of heat from high-temperature areas to low-temperature areas, thereby ensuring the stability and reliability of the heat dissipation system. At the same time, this design significantly relieves the problem of local heat concentration, improving the operating life of the aperture under high load conditions. In addition, for lasers working under high load conditions, the stability of the aperture directly determines the quality of the laser beam output during long-term operation. By significantly relieving the problem of local heat concentration, the present design not only improves the operating life of the aperture, but also effectively suppresses the distortion of the laser beam profile, ensuring the stability of the intensity distribution of the laser output, thereby meeting the requirements of high-precision machining, precision measurement and other application scenarios that require high-quality beams.

[0044] Example 2

[0045] like Figure 1 As shown, an embodiment of the present invention provides a stepped variable pressure microchannel heat dissipation structure, which comprises an aperture plate 1, a channel inlet / outlet 2, a flow channel 3, a gradually widening microchannel 4, a first stepped variable pressure structure 5 at the microchannel inlet, a second stepped variable pressure structure 6 at the microchannel outlet, and a flow valve 7. The microchannel size range is designed according to heat dissipation requirements, with an inlet section width of 200 μm, gradually expanding outwards radially to 800 μm, an expansion ratio of 4:1, which effectively matches fluid dynamics and heat dissipation performance. Elliptical cylinders are arranged in the inlet section, and by controlling the decreasing minor axis length of the cylinders (from 8 mm to 3 mm) and the increasing number of cylinders (from 1 to 5), initial stepped pressure boosting of the fluid is achieved. The first stepped variable pressure structure 5 effectively alleviates the pressure concentration problem at the microchannel inlet; through the progressively increasing elliptical cylinders, the pressure distribution increases from 2.49 × 10⁻⁶. 4 Pa gradually decreases to an inlet average of approximately 1.8 × 10⁻⁶. 4 Pa. To avoid the impact of the outlet fluid on other components of the heat dissipation system. Furthermore, a series-parallel flow channel design is employed in the microchannel, causing multiple collisions and mixing of the fluid during flow, thus improving heat transfer efficiency. The length of the series flow channel is 2 mm, the width of the parallel section is controlled at 100 μm, and the total length of the flow channel is approximately 8 mm, optimizing the balance between heat dissipation efficiency and structural compactness. Analysis shows that the overall heat dissipation efficiency of the structure is improved by 50%-60%, making it particularly suitable for the thermal management requirements of high-power lasers. The structure of this invention features a stepped pressure-changing structure at the microchannel inlet section, with the number of elliptical cylinders increasing progressively, the minor axis length decreasing progressively, and the total flow cross-section decreasing progressively. This allows for rapid gradient pressurization and acceleration of the fluid, effectively solving the problem of excessive and concentrated pressure at the microchannel inlet.

[0046] Example 3

[0047] In another embodiment of the present application, a high-power laser light stop is provided, comprising a light stop plate 1, and a stepped pressure-increasing micro-channel heat dissipation structure arranged on the light stop plate 1. The stepped pressure-increasing structure arranged in the micro-channel is one of the key innovations of the present application. This structure increases the fluid flow rate to the ideal range by arranging multiple pressure-increasing structures between adjacent micro-channels, while maintaining stable fluid flow. Specifically, the stepped pressure-increasing structure adopts a tapered geometric design, with the inlet width gradually decreasing (e.g., from 8 mm to 2 mm), and the outlet section gradually expanding. Through the combination of tapering and expanding, the kinetic energy of the fluid is effectively increased as it passes through each section of the pressure-increasing structure, thereby avoiding the common problems of flow rate slowing down and flow stagnation in traditional micro-channels. In addition, the stepped pressure-increasing structure further optimizes the heat exchange performance through a distributed turbulence design. Elliptical or polygonal cylinder turbulence modules are arranged in the gap between the front and rear end micro-channels, with their spacing and shape being finely adjusted according to the power distribution characteristics of the light stop. For example, in high heat flux areas, the cylinder spacing is reduced to 1 mm to enhance local fluid mixing and heat exchange; while in low heat flux areas, the cylinder spacing can be increased to 5 mm to reduce flow resistance and improve overall heat dissipation efficiency. Such layout design enables the light stop to maintain good heat dissipation performance under different thermal load conditions.

[0048] Those skilled in the art will readily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A stepped voltage microchannel heat sink structure, characterized by, The structure comprises a flow channel (3), a widening micro-channel (4) arranged in the flow channel (3), a first step pressure changing structure (5) arranged at the inlet of the widening micro-channel (4), and a second step pressure changing structure (6) arranged at the outlet of the widening micro-channel (4). The first step pressure changing structure (5) and the second step pressure changing structure (6) comprise a plurality of step elliptical cylinder arrays, the number of elliptical cylinders increases step by step, the length of the minor axis of the elliptical cylinder decreases step by step, and the fluid flow cross-sectional area decreases step by step. When the fluid flows through the elliptical cylinder, the local flow pressure increases due to the narrowing of the channel size, forcing the flow velocity to increase to form a jet effect to accelerate the fluid. Each time the fluid passes through the narrowest flow area between the elliptical cylinders, the pressure and the jet flow increase. With the step-by-step increase of the elliptical cylinder, the total flow area of each step decreases in turn, forming a greater pressure increase and flow velocity increase. Finally, the fluid enters the widening micro-channel (4) at a higher flow rate to achieve flow heat exchange at high power. A turbulence array is arranged between the outlet of the first step pressure changing structure (5) and the second step pressure changing structure (6) and the inlet of the widening micro-channel (4) to promote the full mixing of the fluid and balance the influence of the flow at different positions. The first step pressure changing structure (5), the second step pressure changing structure (6), the turbulence array, and the widening micro-channel (4) are designed according to the specific power distribution and the flow channel pressure distribution.

2. The stepped variable pressure microchannel heat sink of claim 1, wherein, The first step pressure changing structure (5) and the second step pressure changing structure (6) adopt an elliptical cylinder structure with a streamlined shape.

3. The stepped variable pressure microchannel heat sink of claim 1, wherein, The first step pressure changing structure (5) and the second step pressure changing structure (6) adopt a triangular cylinder, a polygonal cylinder, or a cylinder structure with a widening shape.

4. The stepped variable pressure microchannel heat sink of any one of claims 1-3, wherein, The widening micro-channel (4) adopts a widening size design to match the heat dissipation requirements of different power distributions.

5. The stepped variable pressure microchannel heat sink of claim 4, wherein, The widening micro-channel (4) applies a step-by-step pressure increasing / decreasing structure locally.

6. The stepped variable pressure microchannel heat sink of claim 4, wherein, The widening micro-channel (4) is connected in series and parallel to make the fluid collide and mix.

7. The stepped variable pressure microchannel heat sink of claim 6, wherein, The channel design size of the widening micro-channel (4) increases in turn along the outward radius of the aperture.

8. The stepped variable pressure microchannel heat sink of claim 7, wherein, The widening micro-channel (4) is processed in multiple segments, and multiple step pressure changing structures are arranged in adjacent segment micro-channels to re-pressurize and accelerate the fluid to strengthen its flow.

9. A stepped variable pressure microchannel heat sink structure according to any one of claims 1-3, wherein, A channel inlet and outlet (2) is arranged on the front or side of the flow channel (3).

10. The stepped variable pressure microchannel heat sink of any one of claims 1-3, wherein, A flow valve (7) is arranged at the end of the flow channel (3). The flow valve (7) is used for feedback and adjustment of the flow of the aperture branch to control the flow through the aperture branch in time.

11. A high power laser cutoff shutter, characterized by, The structure comprises an aperture plate (1), and a step pressure changing type micro-channel heat dissipation structure arranged on the aperture plate (1).

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