A microchannel heat sink with a non-uniform topological ridge structure and its heat dissipation method

Abstract

This invention belongs to the field of microchannel enhanced heat dissipation technology, and relates to a microchannel heat sink with a non-uniform topological ridge structure and its heat dissipation method. It includes a substrate with pre-fabricated flow channel grooves, divided into a lower flow channel groove and an upper flow channel groove. The lower flow channel groove has two symmetrical inlets, and the upper flow channel groove has an outlet. A liquid inlet and a liquid outlet are machined through the substrate, communicating with each other. The liquid inlet is connected to the inlet, and the liquid outlet is connected to the outlet. An upper channel ridge and a lower channel ridge are machined within the substrate, with the upper channel ridge located at the liquid inlet end of the upper flow channel groove and the lower channel ridge located at the liquid outlet end of the lower flow channel groove. Each group of channel ridges contains multiple ridge blocks, and the channel ridges adopt a convex zigzag distribution structure. Specifically, the length of the ridge blocks gradually changes linearly from both sides to the center, with the length of the ridge blocks in the central region being greater than that in the side regions. A flow channel for coolant is formed between two adjacent ridge blocks. This invention solves the problem of limited heat dissipation capacity in current microchannel heat sinks.

Description

Technical Field

[0001] This invention belongs to the field of microchannel enhanced heat dissipation technology, specifically relating to a microchannel heat sink with a non-uniform topological ridge structure and its heat dissipation method. Background Technology

[0002] With the rapid development of high-power semiconductor devices such as high-performance central processing units, high-power light-emitting diodes, and lasers towards higher integration, smaller size, and higher power density, the heat generated during device operation is highly concentrated, and the local heat flux density increases sharply. This has become a core bottleneck restricting the improvement of device performance, the extension of service life, and the guarantee of operational safety. If the large amount of heat generated by concentrated heat sources during the operation of high-power electronic components cannot be removed in a timely and uniform manner, it will not only cause the chip operating temperature to exceed the safe threshold, leading to device performance degradation and decreased signal stability, but also cause uneven temperature field distribution within the device. This results in significant thermal stress and strain, exacerbating the risk of device structural deformation, interface bonding failure, and material fatigue damage. In severe cases, it can directly lead to chip warping, cracking, or even the scrapping of the entire electronic device, seriously affecting the reliability of high-power semiconductor devices in key fields such as aerospace, precision instruments, and new energy.

[0003] To address the aforementioned thermal management challenges of high-power semiconductor devices, microchannel heat sinks (MHS) leverage the high specific surface area advantage of their micron-scale flow channel structure to effectively enhance convective heat transfer. They can quickly and uniformly remove heat generated by concentrated heat sources, effectively suppressing local overheating and temperature gradients, and reducing internal thermal stress and strain levels. This has become a core technological path for achieving efficient thermal management of high-power semiconductor devices and ensuring the structural integrity and long-term stable and reliable operation of the devices, and has been widely researched and applied in the field of thermal management of high-power electronic components.

[0004] Traditional microchannel radiators typically employ a uniform, evenly distributed channel ridge structure. However, this highly homogenized geometric design limits the synergistic optimization of the flow and temperature fields. In microscale flow heat transfer, there is a strong coupling relationship between fluid flow resistance loss and heat transfer performance. As the fluid flows along the channel, its thermophysical properties, such as temperature and viscosity, evolve, leading to inconsistencies between the actual heat transfer requirements and flow characteristics in different channels. Traditional uniform structures force the fluid to experience equal geometric constraints and flow resistance across all channels, resulting in a mismatch between "flow resistance distribution" and "heat transfer requirement distribution." Specifically, unnecessary ineffective pressure drop losses occur in regions with low thermal resistance, while in bottleneck regions where the thermal boundary layer thickens and heat transfer performance deteriorates, the lack of structural variation prevents sufficient turbulence disturbance or effective heat transfer area. This mismatch between flow resistance and heat transfer capacity causes ineffective pump power dissipation, making it difficult for the radiator to achieve optimal overall energy efficiency under limited system pressure drop.

[0005] In summary, existing microchannel heat sinks have limited heat dissipation capacity due to structural design limitations in practical applications. Their thermal management performance and structural reliability are insufficient to meet the demands of high-power electronic components that are developing towards higher power density and greater precision. Summary of the Invention

[0006] The purpose of this invention is to provide a microchannel heat sink with a non-uniform topological ridge structure and its heat dissipation method, which solves the problem of limited heat dissipation capacity of current microchannel heat sinks.

[0007] This invention is achieved through the following technical solution:

[0008] This invention discloses a microchannel heat sink with a non-uniform topological ridge structure, including a substrate, in which flow channels are pre-fabricated, the flow channels being divided into a lower flow channel and an upper flow channel; the lower flow channel has two symmetrical inlets, and the upper flow channel has an outlet; an inlet and an outlet are processed on the substrate, penetrating the substrate; the inlet is connected to the outlet, and the outlet is connected to the outlet.

[0009] Two sets of channel ridges are processed in the substrate, namely the upper channel ridge and the lower channel ridge. The upper channel ridge is located at the liquid inlet end of the upper flow channel groove, and the lower channel ridge is located at the liquid outlet end of the lower flow channel groove. The upper channel ridge and the lower channel ridge have the same structure.

[0010] Each channel ridge contains multiple ridge blocks. The channel ridges adopt an upward convex zigzag distribution structure. Specifically, the length of the ridge blocks gradually changes linearly from both sides to the center, and the length of the ridge blocks in the central region is greater than the length of the ridge blocks in the two side regions.

[0011] The space between two adjacent ridges is a coolant flow channel.

[0012] Furthermore, the channel ridges are symmetrically distributed from left to right, and the channel ridges include 2n+1 ridge blocks. The line connecting the center point of the (n+1)th ridge block with the center point of the first ridge block and the center point of the (2n+1)th ridge block forms an angle, which is called the vertex angle; where n is a positive integer.

[0013] Furthermore, the angle of the apex angle is 120°-150°.

[0014] Furthermore, multiple laser light-emitting units are provided on the bottom surface of the substrate, and the laser light-emitting units are correspondingly positioned at the center projection position of each flow channel.

[0015] Furthermore, both the inlet and outlet are cylindrical holes, and both the inlet and outlet are arc-shaped openings formed by the intersection of the cylindrical holes and the flow channel groove.

[0016] Furthermore, the transition section connecting the liquid inlet and the inlet is a first circular arc flow channel, and the central angle of the first circular arc flow channel is the arc angle of the inlet flow channel. ;

[0017] The transition section connecting the outlet and the liquid outlet is a second circular arc flow channel, and the central angle of the second circular arc flow channel is the arc angle of the outlet flow channel. ;

[0018] The ratio of the radius of the inlet flow channel arc angle to the radius of the outlet flow channel arc angle satisfies: .

[0019] Furthermore, the radius of the inlet flow channel arc angle is 0.63 ± 0.05 rad.

[0020] Furthermore, the arc angle of the outlet flow channel is 2.06 ± 0.05 rad.

[0021] Furthermore, the microchannel heat sink is made of a nickel-based rare earth alloy.

[0022] The present invention also discloses a heat dissipation method for a microchannel heat sink with a non-uniform topological ridge structure, comprising the following steps:

[0023] The coolant enters through the inlet and flows into the lower channel groove through two inlets. In the lower channel groove, the coolant impacts the lower channel ridge along the flow direction, forming a vortex diffusion zone around the lower channel ridge to enhance heat transfer.

[0024] Subsequently, the coolant enters the upper channel channel from the lower channel channel and forms a vortex diffusion zone around the upper channel ridge again to enhance heat transfer. Finally, the coolant flows from the outlet of the upper channel channel into the outlet and is discharged.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The microchannel heat sink with a non-uniform topological ridge structure disclosed in this invention achieves simultaneous improvement in heat dissipation performance and structural reliability through the synergistic design of a multi-channel structure and a non-uniform channel ridge topology. Specific advantages are as follows:

[0027] Firstly, by setting up two layers of flow channels (upper and lower layers) within the substrate, the coolant forms a stratified flow path in space. The differences in heat exchange location and flow direction between the different layers of flow channels effectively extend the coolant's contact time in high heat flux density regions and reduce the risk of extreme temperature rise within a single flow channel, thus improving the spatial distribution characteristics of the temperature field from a structural perspective. The two-layer distribution of flow channels provides the necessary spatial basis for subsequent flow-induced and heat transfer control via the channel ridge structure, avoiding the problems of enhanced disturbance and sharp increase in pressure drop found in single-layer structures.

[0028] Secondly, channel ridges are machined within the substrate, located at the transition points between the upper and lower flow channel grooves. This creates controlled disturbances in the critical region where the coolant flow direction changes, enhancing the heat transfer capacity of the transition area while preventing the formation of stagnant zones or localized heat accumulation at the transition points. The symmetrical spatial arrangement of the upper and lower channel ridges creates a synergistic effect of temperature field disturbances between layers, effectively suppressing the expansion of localized high-temperature regions into the overall structure, thereby reducing the overall temperature gradient.

[0029] Secondly, the channel ridge adopts an upward-convex zigzag distribution structure, exhibiting a "short on both sides, long in the middle" zigzag topology. This enhances fluid exchange, allowing the high-temperature fluid near the laser emitting unit wall to be promptly replaced by a low-temperature fluid, thereby suppressing the continuous thickening of the thermal boundary layer. This upward-convex zigzag distribution structure significantly improves the local heat transfer coefficient while avoiding the continuous high resistance loss caused by traditional continuously reinforced structures, thus effectively controlling the system pressure drop level while improving the overall heat dissipation coefficient. The channel ridge of the upward-convex zigzag distribution structure exhibits a form that is shorter on both sides and longer in the middle along the channel length direction. Compared to a channel ridge structure with a uniform length, more material is distributed in the central region of the structure, which helps to increase the moment of inertia of the structural cross-section and has a positive effect on improving the overall structure's resistance to deformation.

[0030] The synergistic mechanism formed by the double-layer flow channel arrangement, the double-layer channel ridge arrangement, and the convex zigzag distribution structure of the channel ridge makes the internal temperature field of the heat sink tend to be evenly distributed, significantly weakening the local temperature peaks and the temperature gradient concentration phenomenon caused by them. Thus, while enhancing heat transfer, the maximum thermal strain is significantly reduced. This successfully solves the technical contradiction that the improvement of heat transfer efficiency in the heat dissipation process of high-power devices is often accompanied by an increase in structural thermal stress, and breaks through the engineering limitation of traditional microchannel heat sinks that "enhanced heat transfer inevitably leads to higher thermal strain".

[0031] Furthermore, the channel ridges are symmetrically distributed from left to right, comprising 2n+1 ridge blocks. The line connecting the center point of the (n+1)th ridge block with the center points of the first and (2n+1)th ridge blocks forms a vertex angle, with an angle of 120°-150°. This angle range is beneficial for enhancing heat exchange between the coolant and the ridge blocks, thus strengthening the overall temperature control capability. This large-angle structure allows for smoother coolant flow, effectively alleviating the operating load on the cooling system's pumping equipment by reducing wall friction and local pressure drop losses. Simultaneously, keeping the angle below 150° prevents the channel ridges from weakening their guiding effect due to excessively large vertex angles, thereby helping to maintain the controllability of coolant flow during the distribution process and the uniformity of coolant supply to each branch.

[0032] Furthermore, this invention combines the convex zigzag distribution structure with nickel-based rare earth alloy material, making full use of the excellent high-temperature mechanical properties and corrosion resistance of the nickel-based rare earth alloy material. This allows the heat sink to meet long-term service requirements without gold plating, effectively avoiding the risk of microchannel blockage caused by gold layer peeling, and further improving the structural strength and operational reliability of the heat sink in high power density application scenarios. Attached Figure Description

[0033] Figure 1 A perspective view of a microchannel heat sink with an equal-length ridge distribution structure for the channel ridges;

[0034] Figure 2 for Figure 1 The bottom view, specifically the base view of the microchannel heat sink;

[0035] Figure 3 for Figure 1 Side view;

[0036] Figure 4 A perspective view of a microchannel heat sink with a length cosine distribution structure for the channel ridges;

[0037] Figure 5 A perspective view of a microchannel heat sink with a sinusoidal length distribution structure for the channel ridges;

[0038] Figure 6 A perspective view of a microchannel heat sink with a concave zigzag distribution structure for the channel ridges;

[0039] Figure 7 A perspective view of a microchannel heat sink with a convex zigzag distribution structure for the channel ridges;

[0040] Figure 8 Nusselt-Reynolds number curves for five structural models of microchannel heat sinks;

[0041] Figure 9 The comprehensive heat dissipation coefficient-Reynolds number curves corresponding to five structural models of microchannel heat sinks;

[0042] Figure 10 The single equivalent strain-Reynolds number curves corresponding to five structural models of microchannel heat sinks;

[0043] Figure 11 The side view of the thermal strain distribution of the ULR-MHS model of the microchannel radiator when the coolant flow rate is 11 m / s.

[0044] Figure 12 The side view of the thermal strain distribution of the CLR-MHS model of the microchannel radiator when the coolant flow rate is 11 m / s.

[0045] Figure 13 The side view of the thermal strain distribution of the SLR-MHS model of the microchannel radiator when the coolant flow rate is 11 m / s.

[0046] Figure 14 The side view of the thermal strain distribution of the CFR-MHS model of the microchannel radiator when the coolant flow rate is 11 m / s.

[0047] Figure 15 The side view of the thermal strain distribution of the VFR-MHS model of the microchannel radiator when the coolant flow rate is 11 m / s.

[0048] Among them, 1. substrate; 2. liquid inlet; 3. liquid outlet; 4. flow channel; 41. inlet; 42. outlet; 5. channel ridge; 6. laser light-emitting unit. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0050] The detailed description of the embodiments of the present invention provided in the following figures is not intended to limit the scope of the claimed invention, but merely to illustrate one selected embodiment of the invention. All other embodiments obtained by those skilled in the art based on the figures and embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0051] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0052] This invention proposes a microchannel heat sink with a non-uniform topological ridge structure. By adjusting the geometric distribution of the channel ridges 5, the flow direction and local velocity of the coolant are optimized, achieving the dual goals of high heat transfer efficiency and low thermal strain.

[0053] like Figure 1 As shown, the microchannel heat sink includes a substrate 1, in which flow channels 4 are pre-fabricated. The flow channels 4 are distributed in two layers, namely a lower flow channel and an upper flow channel. The lower flow channel has two symmetrical inlets 41, and the upper flow channel has an outlet 42. A liquid inlet 2 and a liquid outlet 3 are processed on the substrate 1, penetrating the substrate 1; the liquid inlet 2 is connected to the inlet 41, and the liquid outlet 3 is connected to the outlet 42.

[0054] Two sets of channel ridges 5 are processed in the substrate 1, which are divided into upper channel ridges and lower channel ridges. The upper channel ridge is located at the liquid inlet end of the upper flow channel groove, and the lower channel ridge is located at the liquid outlet end of the lower flow channel groove. The upper channel ridge and the lower channel ridge have the same structure. Each set of channel ridges 5 contains multiple ridge blocks. The flow channel of coolant is between two adjacent ridge blocks. Multiple laser light-emitting units 6 are provided on the bottom surface of the substrate 1. The laser light-emitting units 6 are correspondingly arranged at the center projection position of each flow channel.

[0055] Wherein, the length of substrate 1 is L The width of substrate 1 is W The height of substrate 1 is H The width of a single flow channel is W c The width of the ridge is W d The height of the flow channel 4 is H b The spacing between the two flow channel grooves 4 is H c .

[0056] Two inlets 41 allow coolant to enter the lower flow channel symmetrically from both sides. After a U-shaped turn, the coolant enters the upper flow channel from the lower flow channel, thus forming a continuous layered flow path inside the substrate 1.

[0057] Furthermore, both the inlet 2 and the outlet 3 are cylindrical holes with a radius of [missing information]. r The transition section connecting the inlet 2 and the inlet 41 is a first circular arc flow channel, and the central angle of the first circular arc flow channel is the arc angle of the inlet flow channel. β The transition section connecting the liquid outlet 3 and the outlet 42 is a second circular arc flow channel, and the central angle of the second circular arc flow channel is the arc angle of the outlet flow channel. α The ratio of the radius of the inlet flow channel arc angle to the radius of the outlet flow channel arc angle satisfies: The radius of the inlet flow channel arc angle is 0.63 ± 0.05 rad, and the radius of the outlet flow channel arc angle is 2.06 ± 0.05 rad.

[0058] like Figure 2 As shown, this invention integrates multiple laser light-emitting units 6 onto the bottom surface of a substrate 1, arranging them in a one-dimensional array along the same direction. By providing optical isolation structures between adjacent laser light-emitting units 6, mutual interference between them can be avoided, thus forming a multi-aperture lasing structure. Based on this array configuration, the overall output power of the chip can be increased by increasing the number of laser light-emitting units 6. In the heat source setting, the heat source density of a single laser light-emitting unit 6 is set to 200 W / cm². 2 The heat source density in the non-luminous area is set to 0.

[0059] Among them, such as Figure 2 and Figure 3 As shown, the length of the laser emitting unit 6 is L a The width of the laser light-emitting unit 6 is W a The height of laser light-emitting unit 6 is h a The spacing between the 6 laser light-emitting units is W b .

[0060] The microchannel heat sink uses a high-performance nickel-based rare-earth alloy as its structural material. By introducing rare-earth elements for microalloying, the material's coefficient of thermal expansion is adjusted to 11 ppm / K, achieving high-precision expansion matching with the semiconductor chip; while maintaining a high thermal conductivity of 94 W / (m·K). This material achieves excellent corrosion resistance without gold plating, avoiding the risk of gold layer detachment and blockage of the microchannels during long-term operation.

[0061] Microchannel heat sinks utilize metallic materials incorporating rare earth elements as structural materials because the introduction of rare earth elements helps improve the material's corrosion resistance. Due to their larger atomic radii, rare earth elements can occupy vacancies within the matrix and near grain boundaries to a certain extent, thus affecting the diffusion behavior of alloying elements and inhibiting the formation of harmful σ-phase and χ-phase intermetallic compounds, thereby improving the material's corrosion resistance. Simultaneously, the fine oxides or oxysulfides formed by rare earth elements in the material help stabilize and refine the microstructure. Based on these studies, using materials incorporating rare earth elements is beneficial for improving the service stability of microchannel heat sinks.

[0062] This invention designs five distinct channel ridge distribution schemes to explore the suppression mechanism of thermal strain by non-uniform topology.

[0063] The first type, Uniform-Length Ridge Microchannel Heat Sink (ULR-MHS): serves as a baseline group, such as... Figure 1 As shown, all the ridge blocks of channel ridge 5 have the same length; channel ridge 5 is straight and continuously arranged.

[0064] The physical significance of this structure is to establish a baseline for comparing physical functions, which is used to quantify the gains brought about by non-uniform structures.

[0065] The second type is the length-cosine distribution structure (Cosine-Length Ridge Microchannel Heat Sink, CLR-MHS): For example... Figure 4 As shown, the length of the ridge block of channel ridge 5 is distributed according to the cosine function law, showing the characteristics of being long on both sides and short in the middle.

[0066] The third type is the sine-length distribution structure (Sine-Length Ridge Microchannel Heat Sink, SLR-MHS): For example... Figure 5 As shown, the length of the ridge block of channel ridge 5 is distributed according to a sine function, exhibiting the characteristics of being short on both sides and long in the middle.

[0067] The second and third types are both based on function-modulated ridge length distribution structures. This structure introduces a regular length variation in the flow direction, thereby generating a flow resistance modulation effect. Specifically, in regions with longer ridge lengths, the contact path between the fluid and the wall increases, enhancing heat transfer, while simultaneously increasing flow resistance. In regions with shorter ridge lengths, the fluid is more likely to form cross-channel flow between adjacent channels. Furthermore, the periodic variation in ridge length causes the flow state of the coolant with the wall to continuously change as it flows through different ridge regions, thereby reducing heat accumulation near the wall and preventing the formation of a stable high-temperature boundary layer.

[0068] The fourth type is the concave-folded ridge microchannel heat sink (CFR-MHS): [Example image would be inserted here] Figure 6 As shown, the channel ridge 5 is arranged in a zigzag shape with the central ridge block concave inward, exhibiting the characteristics of being long on both sides and short in the middle.

[0069] The fifth type is the convex-folded structure (Convex-Fold Ridge Microchannel Heat Sink, VFR-MHS): [Example image would be inserted here] Figure 7 As shown, the channel ridge 5 is arranged in a zigzag shape with the central ridge block protruding outwards, exhibiting the characteristics of being short on both sides and long in the middle.

[0070] The fourth and fifth structures are zigzag non-uniform ridge structures. The channel ridges 5 exhibit a symmetrical distribution from left to right. Each channel ridge 5 comprises 2n+1 ridge blocks. The line connecting the center point of the (n+1)th ridge block to the center points of the first and (2n+1)th ridge blocks forms an angle, called the apex angle. The angle of the apex angle is 120°-150°, where n is a positive integer.

[0071] The vertex has the following two functions:

[0072] Suppressing dead zones across the entire plane: If the angle increases further (e.g., exceeding 150° or even approaching 180°), the fluid will undergo a violent impact-like distribution upon entering the flow channel, causing the fluid in the edge side channels to almost stagnate. Maintaining the angle within 150° avoids the weakening of the channel ridge's guiding effect due to an excessively large apex angle, thus helping to maintain the controllability of coolant flow during the distribution process and the uniformity of coolant supply to each branch.

[0073] Reduced frictional losses: Compared to narrow-angle designs of less than 120°, the large angle of 120°-150° increases heat exchange between the fluid and the ridge block, enhancing overall temperature control. This large-angle structure also allows for smoother fluid flow, effectively reducing the operating load of the cooling system's pumping equipment by decreasing wall friction and local pressure drop losses.

[0074] Each channel ridge 5 comprises 19 ridge blocks. The center point of the top of the 10th ridge block forms an angle with the line connecting the center points of the tops of the 1st and 19th ridge blocks, with the center point of the 10th ridge block as the vertex. This angle is 2.40 rad. When the fluid impacts the top of the ridge, it generates strong streamline deflection and separation, forming a complex vortex diffusion zone. This vortex greatly enhances energy exchange within the fluid, rapidly carrying away the latent heat generated in localized high-temperature areas. The zigzag ridge structure guides the fluid to accelerate towards both sides of the channel, forming a transverse secondary flow. This not only increases the scouring intensity on the sidewalls but also effectively dilutes the localized high-temperature field caused by non-uniform heat sources through this active guidance.

[0075] The above five structures correspond to five models, namely the ULR-MHS model, CLR-MHS model, SLR-MHS model, CFR-MHS model, and VFR-MHS model. The total length of each model ( L ),width( W ) and height ( H They are completely identical; the flow channel layout adopts a design with dual inlets 41 and a single outlet 42. The fluid undergoes a U-shaped turn inside and is distributed in two parallel fluid domains, one above the other.

[0076] Features of inlet 41 and outlet 42: The junction of inlet 41 adopts a streamlined intersection design, using the intersection of cylindrical holes and flow channel grooves 4 to generate an inlet flow channel arc angle to replace dead angles. This is intended to eliminate flow dead zones and alleviate pressure drops at inlet 41, ensuring a smooth transition of fluid to the parallel flow channel array; outlet 42 has the same features.

[0077] The five models above share a standardized set of global geometric parameters to ensure the impartiality of the comparative experiments. (Reference) Figures 1-3 The specific parameters are shown in Table 1.

[0078] Table 1 Global geometric parameters of the model

[0079] Overall parameters numerical values Overall parameters numerical values Length of substrate 1 ( ) 27.5 mm The radius of the cylindrical hole is ( ). 2.8 mm Width of substrate 1 ( ) 12.0 mm Outlet flow channel radius ( ) 2.06 rad Height of substrate 1 ( ) 1.9 mm Inlet flow channel radius ( ) 0.63 rad <![CDATA[Length of the laser light-emitting unit 6 ( L a )]]> 2.1 mm <![CDATA[The height of the flow channel groove 4 ( H b )]]> 0.5 mm <![CDATA[Width of the laser light emitting unit 6 ( W a )]]> 0.1 mm <![CDATA[The spacing between the two flow channels 4 ( H c )]]> 0.3 mm <![CDATA[Height of the laser light-emitting unit 6 ( h a )]]> 0.1 mm <![CDATA[Width of the ridge block ( W d )]]> 0.3 mm <![CDATA[Pitch of laser light-emitting unit 6 ( W b )]]> 0.5 mm <![CDATA[Width of a single flow channel ( W c )]]> 0.3 mm

[0080] In the five models described above, the number of ridge blocks in channel ridge 5 remains consistent at 19. These ridge blocks are arranged sequentially along the width of channel ridge 5 and numbered according to their arrangement. While the number of ridge blocks and their overall arrangement are the same across different models, the specific length parameters of each ridge block vary depending on the structural form. To clearly illustrate the length variations of each numbered ridge block in different models, the ridge block length parameters for the five models are summarized, and the corresponding relationships are shown in Table 2. As can be seen from the data in Table 2, the length parameters of each ridge block fall within a certain range of variation across the five different structural models. Specifically, the maximum length of the ridge block in each model is 4.20 mm, and the minimum length is 2.10 mm. The length of different numbered ridge blocks varies within this range according to the structural design requirements. By differentiating the ridge block lengths, various channel ridge 5 distribution patterns can be formed to construct different microchannel heat sink models.

[0081] Table 2. Specific length parameters of the channel ridges for different models

[0082] Rib block number ULR-MHS CLR-MHS SLR-MHS CFR-MHS VFR-MHS 1 4.20mm 4.20mm 2.10mm 4.20mm 2.10mm 2 4.20mm 4.10mm 2.46mm 3.97mm 2.33mm 3 4.20mm 3.91mm 2.82mm 3.74mm 2.56mm 4 4.20mm 3.64mm 3.15mm 3.51mm 2.79mm 5 4.20mm 3.33mm 3.45mm 3.28mm 3.02mm 6 4.20mm 3.00mm 3.71mm 3.05mm 3.25mm 7 4.20mm 2.68mm 3.92mm 2.82mm 3.48mm 8 4.20mm 2.41mm 4.07mm 2.59mm 3.71mm 9 4.20mm 2.20mm 4.17mm 2.36mm 3.94mm 10 4.20mm 2.10mm 4.20mm 2.10mm 4.20mm 11 4.20mm 2.20mm 4.17mm 2.36mm 3.94mm 12 4.20mm 2.41mm 4.07mm 2.59mm 3.71mm 13 4.20mm 2.68mm 3.92mm 2.82mm 3.48mm 14 4.20mm 3.00mm 3.71mm 3.05mm 3.25mm 15 4.20mm 3.33mm 3.45mm 3.28mm 3.02mm 16 4.20mm 3.64mm 3.15mm 3.51mm 2.79mm 17 4.20mm 3.91mm 2.82mm 3.74mm 2.56mm 18 4.20mm 4.10mm 2.46mm 3.97mm 2.33mm 19 4.20mm 4.20mm 2.10mm 4.20mm 2.10mm

[0083] The microchannel heat sink provided by this invention achieves diverse configurations of the internal structure of the channels by rationally designing the number and length distribution of the ridges, while maintaining consistent overall structural dimensions. By setting ridges of different lengths at different channel locations, the flow path of the fluid within the channel can be varied, thereby helping to improve the fluid distribution within the channel and enhance convective heat transfer between the fluid and the wall.

[0084] This invention employs different combinations of ridge block lengths, providing a variety of optional internal configurations for microchannel heat sinks without increasing structural complexity. This enhances the flexibility and adaptability of structural design and facilitates the optimization of channel structures according to different heat dissipation requirements.

[0085] Based on the clearly defined structural composition and geometric arrangement of the aforementioned non-uniform topological ridge microchannel heat sink, in order to obtain the thermal-fluid-structure interaction response characteristics of the heat sink under actual working conditions, this invention further employs a multiphysics coupling analysis method based on computer numerical simulation to calculate and analyze the flow field, temperature field, and thermal strain field of the heat sink under coolant flow and non-uniform heat source loading conditions. The specific implementation process is as follows:

[0086] In the solution stage of the flow field and temperature field:

[0087] The fluid dynamics calculation module in the ANSYS Workbench platform was used to perform steady-state numerical calculations of the three-dimensional flow and heat transfer process of the coolant in the microchannel. A conjugate heat transfer model was established between the fluid region and the solid region to achieve coupled calculation of heat transfer at the solid-liquid interface.

[0088] In terms of physical model setting, for cooling flow conditions with Reynolds numbers in the range of 3850 to 6100, the k-ε turbulence model is used to numerically simulate the turbulent flow behavior in the microchannel to obtain velocity distribution and turbulent characteristic parameters.

[0089] To ensure the stability and accuracy of the calculation results, the grid independence of the computational domain was verified. The grid size was optimized while meeting the required computational accuracy. In this embodiment, a grid of approximately 3.8 × 10⁻⁶ grid cells was used. 6 The structured mesh model of each unit is used, and the heat source contact area is locally refined, with the local minimum mesh size being 0.0001 m.

[0090] Through the above calculation process, the three-dimensional non-uniform temperature distribution field data of the entire radiator are obtained. The overall pressure drop P distribution data provides input parameters for subsequent structural mechanical response analysis.

[0091] In the thermal strain field solution stage:

[0092] The non-uniform temperature distribution field obtained from the first stage calculation As a variable-temperature load mapped to the structural mechanics analysis module, it is used to characterize the thermal deformation effect of the heat sink due to temperature rise during actual operation. The temperature field is applied to the overall structure of the heat sink in the form of a volume load to simulate the expansion trend of a solid structure under non-uniform temperature rise conditions in space.

[0093] Meanwhile, a completely fixed constraint is applied to the top region of the microchannel heat sink, limiting its displacement degrees of freedom in the X, Y, and Z directions to zero, in order to simulate the mechanical clamping and installation constraints that the heat sink is subjected to under actual packaging conditions.

[0094] Under the combined action of non-uniform temperature field load and substrate mechanical constraint, the free thermal expansion of different regions inside the radiator is restricted to varying degrees, thereby inducing the formation of spatially uneven thermal stress and thermal strain fields inside the structure.

[0095] The results of the thermal strain field distribution above show that, under the conditions of coolant flow and heat transfer, there are significant differences in the thermal strain levels in different regions of the structure. The thermal strain state exhibits a multiaxial non-uniform distribution characteristic formed by the combined action of multiple directional positive thermal strain and shear thermal strain components. It is difficult to fully characterize the overall deformation response characteristics of the structure under thermo-fluid-structure interaction using only the thermal strain component in a single direction.

[0096] Therefore, to achieve a unified characterization of the comprehensive deformation degree of the structure under multiaxial thermal strain, and to facilitate quantitative comparative analysis between different models and different spatial locations, the normal thermal strain and shear thermal strain components in each direction of the structure are synthesized and calculated. Based on the mechanical response characteristics of nickel-based rare earth alloys within the operating temperature range, a von Mises equivalent thermal strain model is introduced to convert the anisotropic thermal strain tensor into a single equivalent strain scalar. , which serves as a characterization parameter for evaluating the overall thermal strain level of the structure.

[0097] The formula for calculating a single equivalent variable scalar is as follows:

[0098] ;

[0099] This quantitative index is used to analyze different Reynolds numbers ( The structural stability under the condition is judged. Among them, , , These represent the thermal strain values ​​of the structure in the three principal stress directions. In the plastic deformation analysis, the effective Poisson's ratio... v The value is set to 0.5. In subsequent analyses, thermal strain is characterized by a single equivalent strain.

[0100] Through the fully coupled numerical calculations of the flow field, temperature field, and thermal strain field described above, this invention establishes the correlation between the mechanical and thermal responses of non-uniform topologies under complex operating conditions. The calculation results show that the geometric configuration of the structure not only determines the distribution characteristics of thermal stress but also influences the disturbance behavior of the cooling medium and the evolution of the boundary layer from a fundamental physical mechanism.

[0101] Therefore, this invention first conducts quantitative characterization and comparative analysis of the core heat dissipation performance of the radiator, and calculates the heat transfer intensity index of each model under different flow states. The specific analysis is as follows:

[0102] A comparative analysis of the Nusselt numbers of five models was conducted within the Reynolds number range of 3800 to 6080, and the results are as follows: Figure 8As shown, the Nusselt number, as a core dimensionless parameter for measuring the intensity of convective heat transfer, indicates that a higher value signifies a more significant enhancement of convective heat transfer carried away by the fluid flow, and a higher heat transfer efficiency between the solid wall and the coolant. From... Figure 8 The trend shows that with the increase of Reynolds number, the Nusselt number of all models exhibits a significant and nearly linear increase, reflecting the effect of increased flow velocity on the thinning of the thermal boundary layer and the enhancement of convective heat transfer capacity. Within the entire Reynolds number range studied, the heat transfer capacity of each model shows a clear and consistent gradient: the order is VFR-MHS > CFR-MHS ≈ SLR-MHS > ULR-MHS ≈ CLR-MHS.

[0103] The VFR-MHS model, employing an upward-convex zigzag distribution structure, exhibits a clear advantage in heat transfer performance for channel ridge 5. Quantitative analysis shows that when the Reynolds number reaches 6080, the Nusselt number of VFR-MHS is approximately 0.92% higher than that of the baseline model ULR-MHS. This is mainly attributed to the VFR-MHS model's ability to more effectively optimize the velocity distribution within the flow channel, inducing stronger local disturbances while simultaneously altering the fluid flow direction, thus achieving a considerable improvement in heat transfer efficiency while maintaining a low pressure drop.

[0104] To comprehensively evaluate the performance of microchannel heat sinks, the evaluation model must not only focus on its enhanced convective heat transfer effect, but also comprehensively consider the trade-off between fluid flow energy consumption and heat dissipation performance. To further quantitatively evaluate the overall heat dissipation performance of each model, this invention compares and analyzes the Performance Evaluation Criterion (PEC) of five models within the Reynolds number range of 3800 to 6080. The calculation method is as follows:

[0105] PEC = (Nu / Nu0) / (P / P0) 1 / 3 ;

[0106] Nu0 and P0 are the Nusselt number and pressure drop of the ULR-MHS model, respectively. The Nusselt number reflects the enhancement effect of the model on convective heat transfer, while the pressure drop indirectly measures the flow energy consumption of the fluid. Figure 9 The overall heat dissipation coefficient of each model is shown to vary with Reynolds number. The results show that, within the studied Reynolds number range, the overall heat dissipation performance of the four improved channel ridge models is superior to the benchmark ULR-MHS model, demonstrating the general effectiveness of non-uniform ridge length distribution in improving energy efficiency.

[0107] Among all models, the VFR-MHS model exhibits the most significant advantages:

[0108] 1. Significant performance improvement: The VFR-MHS model exhibits the highest overall thermal efficiency across the entire range, showing a unique trend of monotonically increasing with the Reynolds number. When the Reynolds number reaches 6080, its overall thermal efficiency is approximately 6% higher than that of the ULR-MHS.

[0109] 2. Multi-indicator synergistic optimization: Combining the aforementioned pressure drop and Nusselt number analysis, the superior performance of the VFR-MHS model stems from its "low-resistance, high-efficiency" characteristics. Its convex configuration not only effectively mitigates impact losses at the turning point (U-shaped turning region) and reduces system pressure drop, but also maintains a high Nusselt number by optimizing the flow field distribution in the ridge region. This significant reduction in flow resistance and stable improvement in heat transfer efficiency give the VFR-MHS model excellent energy efficiency ratio under high-precision heat dissipation requirements.

[0110] In contrast, while the SLR-MHS, CLR-MHS, and CFR-MHS models also outperform the baseline model, their overall heat dissipation coefficients show varying degrees of decrease with increasing Reynolds number. This indicates that for these models, as the flow rate increases, the negative power dissipation effect caused by the increased pressure drop gradually dilutes the heat transfer gains.

[0111] The above analysis primarily explains the heat dissipation performance of each model from the perspective of convective heat transfer. It should be noted that during actual operation, the temperature field distribution of microchannel heat sinks not only affects their heat transfer efficiency but also induces thermal expansion and thermal stress response within the structure under thermal loads. Therefore, based on obtaining the steady-state temperature field distribution, it is necessary to further introduce heat-fluid dynamics... The solid-state coupling analysis method analyzes the stress and thermal strain distribution of microchannel heat sinks based on temperature field data to evaluate the structural adaptability and reliability of different structural forms under thermal load conditions.

[0112] Compared to a continuous channel ridge structure without intermediate intervals, all models in this invention adopt a discrete structure composed of multiple separate ridge blocks, giving the channel ridges 5 a segmented distribution. This structure maintains the overall arrangement of the channel ridges 5 while creating interval regions between adjacent channel ridges 5, thus providing space for the expansion and deformation of the solid material under heat.

[0113] Furthermore, by non-uniformly setting the length of each channel ridge 5, the deformation of the channel ridge 5 at different positions during heating varies. This helps to weaken the continuous superposition effect of thermal expansion displacement within the structure, thereby alleviating the stress concentration phenomenon within the structure caused by temperature gradients or local temperature rises. Through the above structural design, the distribution of thermal stress can be adjusted without significantly increasing the overall structural size and processing complexity, thus improving the structural adaptability and operational stability of the microchannel heat sink under thermal loads.

[0114] To further quantify and verify the actual effect of this structural design on thermal strain suppression, this invention uses a coolant flow rate of... Under typical operating conditions, thermal-fluid-structure interaction numerical simulations were performed on microchannel heat sinks with different configurations. Simulations were conducted using the ULR-MHS model, yielding the following results: Figure 11 The side view of the thermal strain distribution is shown; simulation of the CLR-MHS model yields the following results. Figure 12 The side view of the thermal strain distribution is shown; simulation of the SLR-MHS model yields the following results. Figure 13 The side view of the thermal strain distribution is shown; simulation of the CFR-MHS model yields the following results. Figure 14 The side view of the thermal strain distribution is shown; simulation of the VFR-MHS model yields the following results. Figure 15 The side view showing the thermal strain distribution.

[0115] Figures 11-15 This figure shows side views of the thermal strain distribution of different models under a coolant flow rate of 11 m / s. The horizontal line in the figure represents the horizontal reference baseline. Figures 11-15 It is evident that the thermal strain distribution of each model generally exhibits a pattern of larger thermal strain in the central region and smaller thermal strain in the two lateral regions, forming a central convex distribution along the length direction. The thermal strain values ​​near both ends are significantly lower than those in the central region, with the peak thermal strain concentrated in the central region of the structure, indicating that this region is the main area of ​​concentrated thermal strain.

[0116] The reason for the above-mentioned thermal strain distribution characteristics is that the central part of the structure corresponds to the main heat transfer region, where the inlet and outlet related effects during coolant flow are more pronounced, resulting in a larger temperature change range and a higher temperature gradient, thus causing a larger thermal strain. In contrast, the temperature changes on both sides of the structure are relatively mild, and the thermal strain level is correspondingly lower. To further analyze the effect of thermal strain, the single equivalent variable scalar was calculated for different models with a flow velocity of 11 m / s using the single equivalent variable scalar formula. Such as simulation analysis Figure 10As shown, overall, the single equivalent strain values ​​of the five microchannel heat sinks are quite similar. With increasing Reynolds number, the differences in single equivalent strain among the models gradually decrease. It can be clearly observed that in the Reynolds number range of 3800 to 6100, the VFR-MHS model has the smallest single equivalent strain, followed by the ULR-MHS, CLR-MHS, and CFR-MHS models, while the SLR-MHS model has the largest single equivalent strain. Curamik's traditional oxygen-free copper microchannel heat sink-packaged laser diode array chip has a smile effect value of 1.5 μm, while at a Reynolds number of 6080, the VFR-MHS model's smile effect value is only 0.801 μm, representing a suppression of the smile effect of up to 46.58%.

[0117] The "smile effect" of this invention refers to the convex or concave equivalent scalar change in the light-emitting center of each laser-emitting unit 6 due to thermal stress after the laser diode array is packaged. It is a key indicator for measuring the thermal stability of the package. The smile effect value is the sum of the maximum value of the convex equivalent scalar change and the maximum value of the concave equivalent scalar change.

[0118] By comparing single equivalent variable scalars, it was found that the convex zigzag distribution structure not only optimized the local flow field, but also achieved a significant gain of 46.58% reduction in the smile effect while decreasing the temperature gradient. Figure 7 As shown, the channel ridge 5 in the VFR-MHS model exhibits a broken-line distribution with shorter sides and a longer center. This topological layout encourages more material to concentrate in the central region of the structure, thereby increasing the moment of inertia of the cross-section and enhancing the overall structure's resistance to deformation. Furthermore, compared to the continuous curvature variation of an arc-shaped ridge structure, the broken-line ridge exhibits segmented rigidity transfer under stress, with the load being directly and efficiently transferred along each straight segment, resulting in a clear path and reducing additional bending deformation caused by curvature changes. In contrast, an arc-shaped ridge generates a continuous arc-shaped bending effect under stress, accompanied by sustained bending deformation, leading to greater thermal strain. Therefore, the VFR-MHS model exhibits the smallest single equivalent strain in the simulation, a numerical result consistent with theoretical analysis.

[0119] In summary, the present invention ultimately adopts an upward convex zigzag distribution structure as the distribution structure of the channel ridges 5. The number of channel ridges 5 is fixed and the arrangement is orderly, which facilitates processing and assembly. At the same time, it helps to ensure structural consistency and operational stability, and is suitable for a variety of micro-scale heat dissipation application scenarios.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A microchannel heat sink with a non-uniform topological ridge structure, characterized in that, The substrate (1) includes a pre-fabricated flow channel (4) in the substrate (1), which is divided into a lower flow channel and an upper flow channel. The lower flow channel has two symmetrical inlets (41), and the upper flow channel has an outlet (42). An inlet (2) and an outlet (3) that penetrate the substrate (1) are processed on the substrate (1). The inlet (2) is connected to the inlet (41), and the outlet (3) is connected to the outlet (42). Two sets of channel ridges (5) are processed in the substrate (1), which are divided into upper channel ridge and lower channel ridge. The upper channel ridge is located at the liquid inlet end of the upper flow channel groove, and the lower channel ridge is located at the liquid outlet end of the lower flow channel groove. The upper channel ridge and the lower channel ridge have the same structure. Each channel ridge (5) contains multiple ridge blocks. The channel ridge (5) adopts an upward convex zigzag distribution structure. Specifically, the length of the ridge block gradually changes linearly from both sides to the center, and the length of the ridge block in the central region is greater than the length of the ridge block in the two side regions. The space between two adjacent ridges is a coolant flow channel.

2. A microchannel heat sink with a non-uniform topological ridge structure according to claim 1, characterized in that, The channel ridge (5) is symmetrically distributed from left to right. The channel ridge (5) includes 2n+1 ridge blocks. The line connecting the center point of the (n+1)th ridge block with the center point of the first ridge block and the center point of the (2n+1)th ridge block forms an angle, which is called the vertex angle; where n is a positive integer.

3. A microchannel heat sink with a non-uniform topological ridge structure according to claim 2, characterized in that, The angle of the apex is 120°-150°.

4. A microchannel heat sink with a non-uniform topological ridge structure according to claim 1, characterized in that, Multiple laser light-emitting units (6) are provided on the bottom surface of the substrate (1), and the laser light-emitting units (6) are respectively arranged at the center projection position of each flow channel.

5. A microchannel heat sink with a non-uniform topological ridge structure according to claim 1, characterized in that, Both the liquid inlet (2) and the liquid outlet (3) are cylindrical holes, and both the inlet (41) and the outlet (42) are arc-shaped openings formed by the intersection of the cylindrical hole and the flow channel (4).

6. A microchannel heat sink with a non-uniform topological ridge structure according to claim 5, characterized in that, The transition section connecting the liquid inlet (2) and the inlet (41) is the first circular arc flow channel, and the central angle of the first circular arc flow channel is the arc angle of the inlet flow channel. ; The transition section connecting the outlet (3) and the outlet (42) is a second circular arc flow channel, and the central angle of the second circular arc flow channel is the arc angle of the outlet flow channel. ; The ratio of the radius of the inlet flow channel arc angle to the radius of the outlet flow channel arc angle satisfies: .

7. A microchannel heat sink with a non-uniform topological ridge structure according to claim 6, characterized in that, The radius of the inlet flow channel arc angle is 0.63 ± 0.05 rad.

8. A microchannel heat sink with a non-uniform topological ridge structure according to claim 6, characterized in that, The arc angle of the outlet flow channel is 2.06 ± 0.05 rad.

9. A microchannel heat sink with a non-uniform topological ridge structure according to claim 1, characterized in that, The microchannel heat sink is made of nickel-based rare earth alloy.

10. A heat dissipation method for a microchannel heat sink with a non-uniform topological ridge structure as described in any one of claims 1-9, characterized in that, The process includes the following: Coolant enters from the inlet (2) and flows into the lower channel groove through the two inlets (41). In the lower channel groove, the coolant impacts the lower channel ridge along the flow direction, forming a vortex diffusion zone around the lower channel ridge to enhance heat transfer. Subsequently, the coolant enters the upper channel channel from the lower channel channel and forms a vortex diffusion zone around the upper channel ridge to enhance heat exchange. Finally, the coolant flows from the outlet (42) of the upper channel channel into the outlet (3) and is discharged.

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