Micro-channel heat sink and method for local optimization thereof

Abstract

The application provides a micro-channel radiator and a local optimization method thereof. The micro-channel radiator comprises a plurality of heat dissipation units arranged in a first direction in a stacked manner. The heat dissipation unit comprises a first side micro-channel structure and a second side micro-channel structure which are symmetrical about a first plane. The first side micro-channel structure comprises a first channel and a second channel which are intersected in a projection on a second plane. The second side micro-channel structure comprises a third channel and a fourth channel which are intersected in the projection on the second plane. The first channel and the third channel comprise a first inlet and a first outlet. The second channel and the fourth channel comprise a second inlet and a second outlet. The first outlet and the second outlet on the same side are arranged in the first direction. The second outlet is located on a side close to a top surface of the heat dissipation unit. The micro-channel radiator provided by the application has high heat conduction characteristics and a low entropy body state. Through the synergistic regulation of the impact jet flow and the staggered flow alternating structure, the heat boundary layer distribution characteristics are optimized, and the overall heat dissipation performance is improved.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology, and in particular to a microchannel heat sink and its local optimization method. Background Technology

[0002] As semiconductor manufacturing processes continue to evolve towards nanometer-level nodes, electronic products are undergoing a technological revolution characterized by an exponential increase in integration. Following Moore's Law, modern chips have achieved the integration of billions of transistors, directly leading to a superlinear increase in power density. According to data from the International Technology Roadmap for Semiconductors (ITRS), the heat flux density of advanced processor chips has exceeded 100W / cm², with some hotspots reaching levels as high as 300W / cm², approaching the theoretical limits of traditional heat dissipation technologies. Microchannel heat sinks exhibit excellent heat dissipation performance in high heat flux density scenarios, effectively addressing the heat dissipation needs of electronic devices with power consumption exceeding 1000W and heat flux densities exceeding 200W / cm². To achieve highly efficient and enhanced heat dissipation, equipping high-heat-flux-density micro-devices with efficient and compact cooling systems has become a crucial and urgent measure.

[0003] Among them, the impinging jet structure enhances turbulent heat transfer and precisely cools hot spots by vertically impacting the boundary layer; however, the complex vortex structure formed after the jet impact may lead to energy dissipation. The alternating structure forces the fluid to generate secondary flow and vortices by periodically changing the flow direction, disrupting the thermal boundary layer and significantly improving the heat transfer coefficient, but at the same time increasing the flow resistance. Summary of the Invention

[0004] This invention provides a microchannel heat sink and its local optimization method. The microchannel heat sink has high-efficiency heat conduction characteristics and low-entropy body state. By synergistic regulation of the combination of impinging jet and staggered flow alternating structure, the thermal boundary layer distribution characteristics are optimized, thereby improving the overall heat dissipation performance.

[0005] According to one aspect of the present invention, a microchannel heat sink is provided, comprising a plurality of heat sink units stacked along a first direction. Each heat sink unit includes a first-side microchannel structure and a second-side microchannel structure symmetrically arranged about a first plane. The first-side microchannel structure includes a first channel and a second channel intersecting in projection onto a second plane. The second-side microchannel structure includes a third channel and a fourth channel intersecting in projection onto the second plane. The first plane is parallel to the first direction, and the second plane is perpendicular to the first direction. The first channel and the third channel include a first inlet located on the top surface of the heat sink unit and a first outlet located on the side surface of the heat sink unit. The second channel and the fourth channel include a second inlet located on the top surface of the heat sink unit and a second outlet located on the side surface of the heat sink unit. The first outlet and the second outlet on the same side are arranged along the first direction, and the second outlet is located on the side of the first outlet closer to the top surface of the heat sink unit.

[0006] Optionally, the first channel and the third channel include a first portion near the top surface of the heat dissipation unit, a second portion near the bottom surface of the heat dissipation unit, and a first connecting portion located between the first portion and the second portion; the second channel and the fourth channel include a third portion near the bottom surface of the heat dissipation unit, a fourth portion near the top surface of the heat dissipation unit, and a second connecting portion located between the third portion and the fourth portion.

[0007] Optionally, the first part and the passage at the first entrance are provided with a first right-angle turning area, and the third part and the passage at the second entrance are provided with a second right-angle turning area;

[0008] The coolant path of the first channel is as follows: the coolant enters the first channel from the first inlet, impacts the first part of the first channel vertically and flows into the first part, passes through the first connecting part and the second part of the first channel and then flows out from the first outlet of the first channel;

[0009] The coolant path of the second channel is as follows: the coolant enters the second channel from the second inlet, impacts the third part of the second channel vertically, flows into the third part, passes through the second connecting part and the fourth part of the second channel, and then flows out from the second outlet of the second channel;

[0010] The coolant path of the third channel is as follows: the coolant enters the third channel from the first inlet, impacts the first part of the third channel vertically, flows into the first part, passes through the first connecting part and the second part of the third channel, and then flows out from the first outlet of the third channel.

[0011] The coolant path of the fourth channel is as follows: the coolant enters the fourth channel from the second inlet, impacts the third part of the fourth channel vertically, flows into the third part, passes through the second connecting part and the fourth part of the fourth channel, and then flows out from the second outlet of the fourth channel.

[0012] Optionally, the two ends of the first connecting portion and the two ends of the second connecting portion include rounded corners, and the cross-sectional area of ​​the first connecting portion and the second connecting portion gradually decreases from the two ends to the middle along the cross section parallel to the first direction.

[0013] Optionally, the radius of the rounded corner shape is 0.3 mm.

[0014] Optionally, the first part, the second part, the third part, and the fourth part have the same cross-sectional area along the section parallel to the first direction.

[0015] Optionally, the first inlet, the second inlet, the first outlet, and the second outlet are all rectangular in shape.

[0016] Optionally, the dimensions of the first inlet and the second inlet are 1.00mm × 0.25mm, and the dimensions of the first outlet and the second outlet are 1.05mm × 0.25mm.

[0017] Optionally, the microchannel heat sink includes a heat sink substrate, a lower heat sink partition, a middle heat sink partition, an upper heat sink partition, and a top heat sink plate stacked sequentially along a second direction. The second direction is perpendicular to the plane of the heat sink substrate. The heat sink substrate and the middle heat sink partition are connected by a plurality of lower heat sink partitions, and a plurality of lower microchannels are formed between two adjacent lower heat sink partitions. The middle heat sink partition and the top heat sink plate are connected by a plurality of upper heat sink partitions, and a plurality of upper microchannels are formed between two adjacent upper heat sink partitions. The first inlet and the second inlet are located on the top heat sink plate, and the first outlet and the second outlet are located on the side of the heat sink.

[0018] According to another aspect of the present invention, a method for local optimization of a microchannel heat sink is provided, for determining the length structural parameters of a first side inlet and a second side inlet along a third direction in the aforementioned microchannel heat sink, the method comprising:

[0019] The base temperature and inlet pressure drop were selected as the core indicators, and the optimal solution of the length structural parameters of the first side inlet and the second side inlet was obtained by using a second-generation non-dominated sorting genetic algorithm.

[0020] The microchannel heat sink provided in this embodiment of the invention includes a plurality of heat dissipation units stacked along a first direction. Each heat dissipation unit includes a first-side microchannel structure and a second-side microchannel structure symmetrically arranged about a first plane. The first-side microchannel includes a first channel and a second channel that are intersected by projections onto a second plane. The second-side microchannel structure includes a third channel and a fourth channel that are intersected by projections onto a second plane. The first plane is parallel to the first direction, and the second plane is perpendicular to the first direction. The first channel and the third channel include a first inlet located on the top surface of the heat dissipation unit and a first outlet located on the side surface of the heat dissipation unit. The second channel and the fourth channel include a second inlet located on the top surface of the heat dissipation unit and a second outlet located on the side surface of the heat dissipation unit. The first outlet and the second outlet on the same side are arranged along the first direction, and the second outlet is located on the side of the first outlet near the top surface of the heat dissipation unit. The technical solution of this invention involves an impact jet structure where the coolant enters the first and third channels from the first inlet and the second and fourth channels from the second inlet. The first and second channels, the third and fourth channels form a microchannel staggered flow alternating structure, integrating a composite heat transfer mechanism of jet impact and alternating flow. This can solve problems such as uneven heat dissipation in the flow direction, large channel pressure drop, and unstable two-phase flow, and achieve suppression of local temperature peaks at the substrate. The symmetrical arrangement of microchannels helps to avoid coolant deviation or accumulation in the flow channels, allowing the coolant to fully utilize the heat dissipation area and improve heat dissipation efficiency.

[0021] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This invention provides a three-dimensional structural schematic diagram of a microchannel heat sink according to an embodiment of the present invention;

[0024] Figure 2 A three-dimensional structural diagram of a heat dissipation unit provided in an embodiment of the present invention;

[0025] Figure 3 These are the numerical simulation cloud map of the base temperature gradient and the temperature along the path in the embodiments of the present invention;

[0026] Figure 4The graph shows the relationship between the ratio of Nusselt, voltage drop, and overall heat dissipation coefficient to Reynolds number for the embodiments of the present invention and the benchmark model.

[0027] Figure 5 A schematic diagram showing the optimization parameters (l1, l2);

[0028] Figure 6 For normalized and Fitted surface plot with target parameters l1 and l2;

[0029] Figure 7 A diagram showing the distribution of the solution set in a multi-objective optimization model;

[0030] Figure 8 This is a flowchart illustrating local optimization using the NSGA-II algorithm in an embodiment of the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "above," "below," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "above" or "below" another element, it can be formed not only directly "above" or "below" the other element, but also indirectly "above" or "below" the other element through an intermediate element. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are only used to distinguish different components. It should be understood that such terms can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0033] Figure 1 This is a three-dimensional structural diagram of a microchannel heat sink according to an embodiment of the present invention. Figure 2 This is a three-dimensional structural diagram of a heat dissipation unit provided in an embodiment of the present invention, with reference to... Figure 1 and Figure 2 The microchannel heat sink provided in this embodiment of the invention includes a plurality of heat dissipation units 10 stacked along a first direction z. Each heat dissipation unit 10 includes a first-side microchannel structure and a second-side microchannel structure symmetrically arranged about a first plane. The first-side microchannel structure includes a first channel 11 and a second channel 12 intersecting with projections onto a second plane. The second-side microchannel structure includes a third channel 13 and a fourth channel 14 intersecting with projections onto a second plane. The first plane is parallel to the first direction z, and the second plane is perpendicular to the first direction z. That is, the first plane is... Figure 1 In a plane parallel to the y and z directions, the first side microchannel structure can be a left-side microchannel structure, and the second side microchannel structure can be a right-side microchannel structure. The second plane is... Figure 1 In a plane parallel to the x and y directions, the first channel 11 and the third channel 13 include a first inlet 1-1 located on the top surface of the heat dissipation unit and a first outlet 4-1 located on the side of the heat dissipation unit, wherein the first outlet of the third channel 13 is located in... Figure 1 On the side (not shown on the right side), the second channel 12 and the fourth channel 14 include a second inlet 1-2 located on the top surface of the heat dissipation unit and a second outlet 4-2 located on the side of the heat dissipation unit, wherein the second outlet of the fourth channel 14 is located at... Figure 1 On the right side (not shown), the first outlet 4-1 and the second outlet 4-2 on the same side are arranged along the first direction z. The second outlet 4-2 is located on the side of the first outlet 4-1 that is closer to the top surface of the heat dissipation unit, that is, the second outlet 4-2 is closer to the top surface of the heat dissipation unit 10 than the first outlet 4-1.

[0034] Continue to refer to Figure 1 Optionally, the microchannel heat sink includes a heat sink substrate 9, a lower heat sink partition 7, a middle heat sink partition 8, an upper heat sink partition 6, and a top heat sink plate 5, which are stacked sequentially along the second direction y. The second direction y is perpendicular to the plane containing the heat sink substrate 9. Figure 1 The heat sink base 9 and the heat sink middle partition 8 are connected by several lower heat sink partitions 7. Several lower microchannels are formed between two adjacent lower heat sink partitions 7, and a first outlet 4-1 is formed at the end face. The heat sink middle partition 8 and the heat sink top plate 5 are connected by several upper heat sink partitions 6. Several upper microchannels are formed between two adjacent upper heat sink partitions 6, and a second outlet 4-2 is formed at the end face. The first inlet 1-1 and the second inlet 1-2 are located on the heat sink top plate 5, and the first outlet 4-1 and the second outlet 4-2 are located on the side of the heat sink. Figure 3These are the base temperature gradient numerical simulation cloud map and the temperature along the path map in this embodiment of the invention. Figure 4 This is a graph showing the relationship between the ratio of Nusselt coefficient, pressure drop, and overall thermal conductivity to flow rate in the embodiments of the present invention and the baseline model. Figure 3 As shown, the base temperature in this embodiment of the invention exhibits a distribution characteristic of being high at both ends and low in the middle. Simultaneously, the temperature distribution trends along the two paths are highly consistent with the numerical values, indicating that the temperature distribution within the model is symmetrical. The contour plot and the path plot mutually verify each other, intuitively presenting the macroscopic distribution and local variations of the temperature field along the path, demonstrating high reliability. Figure 4 The figure shows a comparison of the novel microchannel heat sink proposed in this invention with the traditional flat double-layer microchannel heat sink in terms of Nusselt number (Nu), voltage drop (P), and overall heat dissipation coefficient. Figure 4 It can be seen that, under the same flow rate conditions, the new microchannel heat sink... The ratios are generally higher than 1.8, reaching 2.5 in some ranges, indicating that its heat transfer performance is significantly better than that of traditional structures, and the enhanced heat transfer effect is obvious. Although the new microchannel radiator introduces some flow resistance, it makes... There was a slight increase, but the overall increase remained within a reasonable and acceptable range. Ultimately, the overall heat dissipation performance indicators... The value is greater than 1.6 under most operating conditions, indicating that the new structure maintains good flow economy while improving heat exchange capacity, and its overall thermal-hydraulic performance is superior to that of the traditional straight channel design. , and These represent the ratio of Nusselt, the ratio of voltage drop, and the overall heat dissipation factor, respectively.

[0035] The microchannel heat sink constructed in this embodiment exhibits unique hydrodynamic characteristics and excellent heat dissipation performance. It includes an upper microchannel, a lower microchannel, and several partitions. The microchannels adopt a stacked structure with non-overlapping vertical projections of the upper and lower channels. The upper microchannels are separated by an upper partition 6 of the heat sink, and the lower microchannels are separated by a lower partition 7 of the heat sink. The partitions are parallel to each other, forming an orderly and efficient fluid channel. The channel heat sink is... Figure 2 The heat dissipation unit 10 shown is an array. Each heat dissipation unit 10 contains four sets of microchannels that do not overlap when projected along the y-axis, and are symmetrical in pairs. The projections of the first outlet 4-1 and the second outlet 4-2 along the y-axis do not overlap, and the two outlet areas appear alternately. The first channel 11 and the third channel 13 also include a first right-angle flow guiding structure 2-1, and the second channel 12 and the fourth channel 14 also include a second right-angle flow guiding structure 2-2. The intersection of the first channel 11 and the second channel 12, as well as the intersection of the fourth channel 13 and the fourth channel 14, includes an alternating flow structure 3. Figure 2The flow direction of the coolant is also shown, wherein the coolant can be a coolant liquid. One part of the coolant liquid enters the upper horizontal channel through the first inlet 1-1, which is perpendicular to the baffle plate, and then enters the upper horizontal channel through the first right-angle guide structure 2-1. It then enters the alternating flow structure 3 to convert between the upper and lower channels, and finally flows horizontally to the first outlet 4-1. Another part of the coolant liquid enters the lower horizontal channel through the second inlet 1-2, which is perpendicular to the baffle plate, and then enters the lower horizontal channel through the second right-angle guide structure 2-2. It then enters the upper and lower horizontal channels through the alternating flow structure 3, and finally flows horizontally to the second outlet 4-2.

[0036] The technical solution of this invention involves an impact jet structure where the coolant enters the first and third channels from the first inlet and the second and fourth channels from the second inlet. The first and second channels, the third and fourth channels form a microchannel staggered flow alternating structure, integrating a composite heat transfer mechanism of jet impact and alternating flow. This can solve problems such as uneven heat dissipation in the flow direction, large channel pressure drop, and unstable two-phase flow, and achieve suppression of local temperature peaks at the substrate. The symmetrical arrangement of microchannels helps to avoid coolant deviation or accumulation in the flow channels, allowing the coolant to fully utilize the heat dissipation area and improve heat dissipation efficiency.

[0037] Optionally, the first and third channels include a first portion (i.e., the upper horizontal channel of the first channel and the upper horizontal channel of the third channel) near the top surface of the heat dissipation unit, a second portion (i.e., the lower horizontal channel of the first channel and the lower horizontal channel of the third channel) near the bottom surface of the heat dissipation unit, and a first connecting portion (i.e., the alternating flow structure of the first channel and the alternating flow structure of the third channel) located between the first and second portions. The second and fourth channels include a third portion (i.e., the lower horizontal channel of the second channel and the lower horizontal channel of the fourth channel) near the bottom surface of the heat dissipation unit, a fourth portion (i.e., the upper horizontal channel of the second channel and the upper horizontal channel of the fourth channel) near the top surface of the heat dissipation unit, and a second connecting portion (i.e., the alternating flow structure of the second channel and the alternating flow structure of the fourth channel) located between the third and fourth portions.

[0038] The first part, the first connecting part, and the second part are connected in sequence to form the first channel or the third channel; the third part, the second connecting part, and the fourth part are connected in sequence to form the second channel or the fourth channel, as detailed below. Figure 2 As shown, the length L1 of the first connecting part and the second connecting part, and the distance L2 of the first side entrance and the second side entrance along the third direction in the plane parallel to the second plane, are determined by simulation based on the theoretical model during the design.

[0039] Optionally, the first part and the channel at the first inlet are provided with a first right-angle turning zone (i.e., the first right-angle guide structure 2-1), and the third part and the channel at the second inlet are provided with a second right-angle turning zone (i.e., the second right-angle guide structure 2-2). By setting the first right-angle guide structure 2-1 and the second right-angle guide structure 2-2, the coolant and the heat sink baffle form a high-speed impact jet. Its kinetic energy is dissipated in the central region of the substrate, producing a significant local cooling effect and forming a low-temperature depression zone on the order of 302.2K. The coolant entering from the jet inlet impacts the bottom surface of the channel at a near-vertical angle, inducing a secondary vortex structure in the mirror-symmetrical right-angle turning zone. This vortex effect increases the coolant velocity by inducing lateral flow, thereby improving heat dissipation performance. Subsequently, it enters the staggered flow alternating structure for mutual conversion between the upper and lower channels, and finally flows horizontally to the outlet. Among these, the unique working condition layout further enhances the mixing effect of the coolant and at the same time disrupts the thermal boundary layer, significantly improving the overall heat exchange effect of the microchannel radiator.

[0040] The coolant path in the first channel is as follows: the coolant enters the first channel from the first inlet, impacts the first part of the first channel vertically, flows into the first part of the first channel, passes through the first connecting part and the second part, and then flows out from the first outlet of the first channel; that is, a part of the coolant impacts the baffle vertically from the first inlet 1-1 impact jet inlet, passes through the first right-angle guide structure 2-1 and enters the upper horizontal channel, then enters the staggered flow alternating structure 3 to convert between the upper and lower channels, and finally flows horizontally to the first outlet 4-1.

[0041] The coolant path in the second channel is as follows: the coolant enters the second channel from the second inlet, impacts the third part of the second channel vertically, flows into the third part, passes through the second connecting part and the fourth part of the second channel, and then flows out from the second outlet; another part of the coolant impacts the baffle vertically from the second inlet 1-2 impact jet inlet, passes through the second right-angle guide structure 2-2 and enters the lower horizontal channel, then enters the staggered flow alternating structure 3 to convert between the upper and lower channels, and finally flows horizontally to the second outlet 4-2.

[0042] The coolant path in the third channel is as follows: the coolant enters the third channel from the first inlet, impacts the first part of the third channel vertically, flows into the first part, passes through the first connecting part and the second part of the third channel, and then flows out from the first outlet of the third channel. The process is similar to the coolant path in the first channel, but the flow direction is reversed.

[0043] The coolant path of the fourth channel is as follows: the coolant enters the fourth channel from the second inlet, impacts the third part of the fourth channel vertically, flows into the third part, passes through the second connecting part and the fourth part of the fourth channel, and then flows out from the second outlet of the fourth channel. The process is similar to the coolant path of the second channel, but the flow direction is reversed.

[0044] Optional, continue to refer to Figure 1 or Figure 2 The two ends of the first connecting portion and the two ends of the second connecting portion include rounded corners, and the cross-sectional area of ​​the first connecting portion and the second connecting portion gradually decreases from the two ends to the middle along the cross section parallel to the first direction.

[0045] The rounded corner design and tapered cross-section of the alternating flow structure jointly contribute to the formation of local high-velocity regions, thereby inducing vortices; at the same time, the enhanced transport effect of the secondary flow further improves the heat dissipation performance. Theoretical simulation calculations show that the heat dissipation effect is best when the radius of the rounded corner is 0.3 mm. Therefore, in a certain implementation, the radius of the rounded corner can be selected as 0.3 mm.

[0046] Optionally, the first, second, third, and fourth parts have the same cross-sectional area along the section parallel to the first direction, thus ensuring that the upper and lower channels in the first and second channels have the same effective heat transfer area and thermal contact area, and the upper and lower channels in the third and fourth channels have the same effective heat transfer area and thermal contact area. Optionally, the first inlet, second inlet, first outlet, and second outlet are all rectangular in shape. Through theoretical simulation calculations, the optimal solution for the dimensions of the first inlet, second inlet, first outlet, and second outlet is determined. Optionally, the dimensions of the first and second inlets are 1.00mm × 0.25mm, and the dimensions of the first and second outlets are 1.05mm × 0.25mm.

[0047] By designing both the first and second inlets to be rectangular, the rectangular inlet area allows the coolant to contact the microchannel wall and the flow guiding structure evenly and fully, thereby maximizing the heat exchange area and improving the heat exchange efficiency per unit volume. This enables the heat sink to achieve higher heat dissipation capacity in a smaller volume, while the reasonable inlet area size helps to reduce the pressure drop and energy consumption of the fluid in the microchannel.

[0048] Optionally, the inlet area is concentrated at the top center of the heat sink, while the center of the base is the area with the most concentrated heat. The coolant injected through the axial flow channel forms a high-speed impact jet with the heat sink baffle under the action of the flow guiding structure. Its kinetic energy is dissipated in the center region of the base, producing a significant local cooling effect, which ensures effective control of the temperature peak.

[0049] The microchannel radiator structure provided in this embodiment of the invention features a left-right symmetry with a central plane parallel to the planes containing the y and z directions. The top inlet, the two side outlets, and the alternating structure are symmetrically arranged. Furthermore, a modular flow channel partition structure is used to divide the fluid domain into four independent regions. Combined with the axisymmetric configuration, flow zoning control is achieved. Each fluid domain passes through both the upper and lower channels, and the alternating structure is used to change the direction of coolant flow.

[0050] This invention also provides a heat dissipation method for a microchannel radiator. Based on the microchannel radiator provided in the above embodiments, the method includes the following steps: after the coolant flows into the channel through the top inlet (first inlet and second inlet), it enters the alternating structure through a right-angle guide structure and finally flows to the outlets on both sides of the microchannel radiator. The rounded corner curve design and the tapered cross-section of the alternating structure jointly promote the formation of local high-velocity regions, thereby inducing vortices; at the same time, the transport enhancement effect of the secondary flow further improves the heat dissipation performance.

[0051] Optionally, after the coolant is injected through the axial flow channel inlet, it impacts the surface of the microchannel partition at high speed, inducing radial diffusion of the coolant. Due to the energy dissipation caused by the impact effect, a significant local temperature field depression is formed in the central region of the substrate.

[0052] Optionally, after passing through a right-angle guide, the coolant flows horizontally through an alternating guide structure in each fluid domain, achieving a single conversion between the upper and lower flow channels. Subsequently, it flows towards the outlet in a dual-mode flow—the main flow is horizontal, and the local Dean vortex secondary flow.

[0053] The microchannel heat sink provided in this embodiment of the invention has the following beneficial effects:

[0054] Firstly, the microchannel heat sink provided in this embodiment of the invention integrates a composite heat transfer mechanism of microchannel staggered flow and jet impact, which can solve problems such as uneven heat dissipation in the flow direction, large channel pressure drop, and unstable two-phase flow, and achieve suppression of local temperature peaks on the substrate.

[0055] Furthermore, by setting up multiple microchannel flow channels with right-angle turning zones, secondary vortices and lateral flow of coolant are induced, increasing the local coolant flow velocity and improving heat dissipation performance.

[0056] Furthermore, the staggered flow alternating structure, through the periodic staggered configuration of the flow channel spatial positions, can enhance the disturbance and mixing of the fluids in the upper and lower layers, improve the cross-layer heat exchange efficiency, and reduce the overall temperature gradient; at the same time, by utilizing the guiding effect of the alternating flow channels, it can alleviate local velocity deviations, reduce flow dead zones, and ultimately construct a dynamic equilibrium flow field that combines efficient heat exchange with low resistance characteristics.

[0057] Furthermore, the symmetrical arrangement of the top outlet and the branch outlet helps to prevent the coolant from flowing off course or accumulating in the flow channel, allowing the coolant to make full use of the heat dissipation area and improve heat dissipation efficiency.

[0058] Furthermore, by setting the size of several upper microchannels to be equal, it can be ensured that the flow resistance and heat transfer characteristics of the coolant remain consistent during passage, which helps to achieve a more uniform heat distribution and more efficient heat transfer, thereby improving the overall heat dissipation efficiency of the radiator.

[0059] Furthermore, by setting the dimensions of several lower microchannels to be equal, the flow of coolant in the lower microchannels becomes more balanced, reducing the flow deviation or vortex phenomenon of coolant during flow, improving the flow stability of coolant, and thus enhancing the heat dissipation effect.

[0060] Secondly, this invention also provides a heat dissipation method for a multi-impact jet topology microchannel radiator with an alternating staggered flow structure. From a fluid path analysis perspective, the coolant is injected through four axially distributed inlet channels on the cover plate, and finally discharged from the outlets on both sides of the upper and lower layers via the alternating staggered flow structure. Notably, the innovative design of the guiding structure significantly alters the coolant's flow pattern: the coolant injected from the first inlet, under the action of the guiding structure, forms a high-speed impacting jet with the heat sink baffle, inducing a secondary vortex structure within the mirror-symmetrical right-angle turning zone. This vortex effect increases the coolant velocity by inducing lateral flow, thereby improving heat dissipation performance. The kinetic energy dissipation of the coolant entering from the second inlet jet inlet generates a significant local cooling effect in the central region of the substrate, forming a low-temperature depression zone on the order of 302.2 K. Subsequently, it enters the alternating staggered flow structure for mutual conversion between the upper and lower channels, finally flowing horizontally to the outlet. This unique operating condition layout further enhances the coolant mixing effect while disrupting the thermal boundary layer, significantly improving the overall heat exchange effect of the microchannel radiator.

[0061] Furthermore, the coolant is divided into four streams, flowing into the radiator via impinging jets, with the coolant flowing from the center to both sides. This center-to-side flow path exhibits natural symmetry, resulting in a more balanced distribution of coolant velocity and flow rate within the fluid domain. This reduces problems such as excessively low local flow velocities and insufficient heat transfer caused by flow deviation. This symmetry ensures that the temperature gradient on both sides of the radiator is more uniform, preventing overheating on one side and ultimately creating a smoother overall temperature field, reducing thermal stress caused by excessive temperature differences in the equipment.

[0062] Furthermore, the central impact and side-flow paths shorten the flow distance of the fluid on one side, reducing frictional resistance. Simultaneously, the symmetrical flow splitting design avoids losses caused by sudden expansion or contraction in localized flow channels due to concentrated flow, making the overall pressure drop more controllable. This helps to reduce the energy consumption of the drive pump while ensuring high cooling efficiency, balancing performance and economy.

[0063] Furthermore, the coolant, through a unique staggered layout, can break the continuity of the laminar boundary layer in the straight flow channel, promote energy transfer between the upper and lower fluid layers, and enhance the ability to carry heat flow to the wall. Moreover, through the alternating symmetrical design of the flow channels, the flow resistance distribution between the upper and lower layers is balanced, avoiding local overflow phenomena, and achieving flow rate and heat load matching across the entire flow field, further optimizing the overall thermal performance of the system.

[0064] This invention also provides a local optimization method for a microchannel heat sink, used to determine the local optimization of the microchannel heat sink along a third direction (as described in the above embodiments). Figure 1 (The negative x-direction in the image) Length structural parameters of the first and second side entrances, the third direction is perpendicular to the first plane, refer to... Figure 1 The first side inlet is the left side inlet, and the second side inlet is the right side inlet. Local optimization methods for the microchannel heat sink include:

[0065] The base temperature and inlet pressure drop were selected as the core indicators, and the optimal solution of the length structural parameters of the first and second side inlets was obtained by using the Non-dominated Sorting Genetic Algorithm II (NSGA-II).

[0066] The microchannel radiator features a multi-impact jet topology with alternating staggered flow patterns. To improve its overall thermodynamic performance, the length and structural parameters of the impact jet inlet need to be optimized. The heat transfer performance of this microchannel radiator can be characterized by the substrate temperature, while the flow performance is reflected by the inlet pressure drop. Given that the impact jet has two independent inlets, this optimization is a multi-objective parameter optimization problem. Its purpose is to obtain the Pareto optimal solution set for the substrate temperature and inlet pressure drop, thereby achieving the best balance between heat transfer and flow performance of the radiator. Figure 5 This is a schematic diagram illustrating the optimization parameters (l1, l2). Figure 6 For normalized and Fitted surface plot with target parameters l1, l2 Figure 7 This is a diagram showing the distribution of the solution set in a multi-objective optimization model. Figure 8 This is a flowchart illustrating the local optimization using the NSGA-II algorithm in an embodiment of the present invention. The local optimization method for microchannel heat sinks specifically includes:

[0067] S1: Define target parameters: Based on the characteristics of the model, select two sets of lengths (l1, l2) of the top-level impact jet inlet as target parameters, where l1 and l2 correspond to the left inlet and the right inlet, respectively.

[0068] S2: Defining Core Indicators: The performance evaluation system for the microchannel radiator provided in this embodiment of the invention selects the base temperature (T) and inlet pressure drop (P) as core indicators. This is based on the following: Base temperature (T) is a key parameter for evaluating heat transfer performance; the lower the temperature, the higher the efficiency of the radiator in removing heat from the heat source. Correspondingly, inlet pressure drop (P) characterizes flow performance, reflecting the flow resistance required to drive the cooling medium through the system. The lower the pressure drop, the less pump power is consumed, and the lower the system's operating energy consumption. Therefore, for this multi-objective optimization problem, simultaneously minimizing the base temperature (T) and the inlet pressure drop (P) essentially aims to achieve the optimal synergistic configuration between efficient heat dissipation and low flow resistance in the radiator.

[0069] S3: Parameter Normalization: To address the spatial prediction bias in the original data caused by the difference in magnitude and dimensionality between the T and P parameters, the microchannel heat sink provided in the above embodiment undergoes min-max normalization preprocessing: through linear transformation X'=(XX min ) / (X max -X min The original parameters are mapped to the interval [0, 1]. This method can eliminate the influence of dimensions, suppress the dominance of high-order parameters on low-order features, and ensure the equivalent contribution of each parameter in multivariate optimization, thereby significantly improving the predictive reliability of the surrogate model. The normalization results are shown in Table 1. Table 1 below shows the first 40 sets of data. For the last 40 sets of data, only the lengths of l1 and l2 are swapped, and the rest of the data remain unchanged.

[0070] S4: Fitting the target parameter polynomial: Establishing normalized polynomials respectively and The fitted curve with the target parameters, the fitted surface, and the distribution of actual simulated data points are as follows: Figure 6 As can be seen from the visualization results, the vast majority of simulation samples are densely distributed within the theoretical response surface region. This spatial distribution characteristic intuitively reflects the model's extremely strong ability to capture data features. The high degree of overlap between data points and the response surface geometrically verifies the rigor of the regression equation in system representation, meeting the core requirements of high-precision modeling.

[0071] S5: Optimization of the NSGA-II Algorithm: This study adopts NSGA-II (Non-dominated sorting genetic algorithm second generation) as the multi-objective optimization solution framework. This algorithm is an improvement on the classic NSGA architecture, effectively resolving the inherent contradiction between convergence and distribution in traditional genetic algorithms by integrating fast non-dominated sorting, an elite retention strategy, and a diversity preservation mechanism based on crowding distance. In the NSGA-II optimization framework, the objective function essentially follows the minimization principle. For multi-objective problems, establishing a weighted mechanism between objectives is crucial. In this embodiment, the weights of P and T are set to 0.5:0.5. Relevant parameters of the NSGA-II algorithm are shown in Table 2.

[0072] S6: Find the Pareto solution for the objective function: Figure 7 The solution set distribution characteristics of the multi-objective optimization model are presented, showing that the Pareto front exhibits a continuous curve shape. No solution in this non-dominated solution set can completely outperform other solutions in the objective space, and all 100 extended prediction solution sets converge to this front region. This distribution pattern confirms that the model possesses good predictive stability. Numerical calculations show that when design variables... and When working synergistically, the system reaches its global optimum. The relative deviations between the extreme values ​​of T and P obtained through numerical simulation and the theoretical predictions are less than the preset threshold (2%), as shown in Table 3. The highest measured deviation is only 0.7%, which effectively verifies the engineering applicability of the mathematical model.

[0073] Table 1. Data Correspondence and Normalization Results

[0074]

[0075] Table 2. NSGA-II Related Parameter Values

[0076]

[0077] Table 3 shows the actual and predicted values ​​of temperature and pressure drop for the optimal combination.

[0078]

[0079] The core of the optimization strategy provided in this invention lies in seeking the optimal balance between heat dissipation efficiency and flow resistance by precisely controlling the geometric parameters l1 and l2. This significantly improves the thermal performance of the model while effectively reducing the energy consumption of the system, thereby achieving synergistic optimization of overall performance.

[0080] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A microchannel heat sink, characterized in that, The device includes multiple heat dissipation units stacked along a first direction. Each heat dissipation unit includes a first side microchannel structure and a second side microchannel structure symmetrically arranged about a first plane. The first side microchannel structure includes a first channel and a second channel that are intersected by projections onto a second plane. The second side microchannel structure includes a third channel and a fourth channel that are intersected by projections onto the second plane. The first plane is parallel to the first direction, and the second plane is perpendicular to the first direction. The first channel and the third channel include a first inlet located on the top surface of the heat dissipation unit and a first outlet located on the side surface of the heat dissipation unit. The second channel and the fourth channel include a second inlet located on the top surface of the heat dissipation unit and a second outlet located on the side surface of the heat dissipation unit. The first outlet and the second outlet on the same side are arranged along the first direction, and the second outlet is located on the side of the first outlet closer to the top surface of the heat dissipation unit.

2. The microchannel heat sink according to claim 1, characterized in that, The first channel and the third channel each include a first portion near the top surface of the heat dissipation unit, a second portion near the bottom surface of the heat dissipation unit, and a first connecting portion located between the first portion and the second portion. The second channel and the fourth channel each include a third portion near the bottom surface of the heat dissipation unit, a fourth portion near the top surface of the heat dissipation unit, and a second connecting portion located between the third portion and the fourth portion.

3. The microchannel heat sink according to claim 2, characterized in that, The first part and the passage at the first entrance are provided with a first right-angle turning area, and the third part and the passage at the second entrance are provided with a second right-angle turning area; The coolant path of the first channel is as follows: the coolant enters the first channel from the first inlet, impacts the first part of the first channel vertically and flows into the first part, passes through the first connecting part and the second part of the first channel and then flows out from the first outlet of the first channel; The coolant path of the second channel is as follows: the coolant enters the second channel from the second inlet, impacts the third part of the second channel vertically, flows into the third part, passes through the second connecting part and the fourth part of the second channel, and then flows out from the second outlet of the second channel; The coolant path of the third channel is as follows: the coolant enters the third channel from the first inlet, impacts the first part of the third channel vertically, flows into the first part, passes through the first connecting part and the second part of the third channel, and then flows out from the first outlet of the third channel. The coolant path of the fourth channel is as follows: the coolant enters the fourth channel from the second inlet, impacts the third part of the fourth channel vertically, flows into the third part, passes through the second connecting part and the fourth part of the fourth channel, and then flows out from the second outlet of the fourth channel.

4. The microchannel heat sink according to claim 2, characterized in that, The two ends of the first connecting portion and the two ends of the second connecting portion have rounded corners, and the cross-sectional area of ​​the first connecting portion and the second connecting portion gradually decreases from the two ends to the middle along the cross section parallel to the first direction.

5. The microchannel heat sink according to claim 4, characterized in that, The radius of the rounded corner is 0.3 mm.

6. The microchannel heat sink according to claim 2, characterized in that, The first part, the second part, the third part, and the fourth part have the same cross-sectional area along the section parallel to the first direction.

7. The microchannel heat sink according to claim 1, characterized in that, The first inlet, the second inlet, the first outlet, and the second outlet are all rectangular in shape.

8. The microchannel heat sink according to claim 7, characterized in that, The dimensions of the first inlet and the second inlet are 1.00mm × 0.25mm, and the dimensions of the first outlet and the second outlet are 1.05mm × 0.25mm.

9. The microchannel heat sink according to claim 1, characterized in that, The microchannel heat sink includes a heat sink substrate, a lower heat sink partition, a middle heat sink partition, an upper heat sink partition, and a top heat sink plate stacked sequentially along a second direction. The second direction is perpendicular to the plane of the heat sink substrate. The heat sink substrate and the middle heat sink partition are connected by a plurality of lower heat sink partitions, and a plurality of lower microchannels are formed between two adjacent lower heat sink partitions. The middle heat sink partition and the top heat sink plate are connected by a plurality of upper heat sink partitions, and a plurality of upper microchannels are formed between two adjacent upper heat sink partitions. The first inlet and the second inlet are located on the top heat sink plate, and the first outlet and the second outlet are located on the side of the heat sink.

10. A method for local optimization of a microchannel heat sink, characterized in that, The method for determining the length structural parameters of the first and second side inlets along a third direction in the microchannel heat sink according to any one of claims 1 to 9, wherein the third direction is perpendicular to the first plane, includes the following local optimization method for the microchannel heat sink: The base temperature and inlet pressure drop were selected as the core indicators, and the optimal solution of the length structural parameters of the first side inlet and the second side inlet was obtained by using a second-generation non-dominated sorting genetic algorithm.

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