Microchannel Heat Sink for Multiple Hotspots

Abstract

The present invention relates to the technical field of radiators, and specifically discloses a microchannel radiator for multiple hot spots, which includes a heat dissipation main body, a rectangular frame edge, and a jet inlet partition plate. The heat dissipation main body is arranged in the rectangular frame edge, and the jet inlet partition plate is arranged on the upper surface of the heat dissipation main body; a jet heat exchange cavity is opened at the upper end of the heat dissipation main body, a jet liquid distribution plate is arranged at the upper end of the jet heat exchange cavity, jet holes are opened on the jet liquid distribution plate, a jet liquid collection cavity is formed between the jet liquid distribution plate and the jet inlet partition plate, a jet inlet is opened on the jet inlet partition plate, a jet area baffle is arranged at the lower end of the jet liquid distribution plate, and jet microchannels are opened at the lower end of the side wall of the jet heat exchange cavity; the present invention adopts a dual-inlet design, combines two heat exchange methods of jet cooling and cross-flow cooling, and improves the heat dissipation efficiency; through the jet liquid distribution plate and the jet area baffle, precise distribution of the fluid and targeted flow rate adjustment are realized, effectively improving the heat dissipation uniformity and temperature uniformity.

Description

Technical Field

[0001] The present invention relates to the technical field of radiators, and specifically discloses a microchannel radiator for multiple hot spots. Background Art

[0002] Heat dissipation for multiple hot spots and non-uniform heat flux density has important application prospects in lasers, plasmas, radar power tubes, etc. With the rapid development of integrated circuit technology, the integration degree of chips has been continuously improved, and the heat generation per unit area has increased significantly. Especially in application scenarios such as high-performance computing and artificial intelligence accelerators, multiple heat-dense areas (hot spots) will form in local areas of the chip. The heat flux density in these hot spot areas can reach hundreds of watts per square centimeter, posing a severe challenge to the heat dissipation of the chip.

[0003] For chip heat dissipation, microchannel liquid cooling technology is generally adopted. For example, the utility model patent with the application number 2024105803715 discloses an embedded shunt microchannel radiator for an electronic chip, including a radiator bottom plate and a radiator top plate. There are multiple microchannels between the radiator bottom plate and the radiator top plate. Multiple shunt micro-units are arranged on the microchannels. The shunt micro-unit includes cavities arranged on the flow channels and turbulators between the flow channels. The microchannel radiator disclosed in this patent adopts a straight channel structure with uniform arrangement. Although it can meet the overall heat dissipation requirements of the chip to a certain extent, there are still the following deficiencies: First, the traditional microchannel structure with uniform arrangement cannot specifically strengthen the heat dissipation effect in the hot spot area, resulting in too high a temperature in the hot spot area, affecting the performance and reliability of the chip; Second, due to the unreasonable distribution of the flow channels, the temperature uniformity in each area is poor, and it is easy to form a large temperature gradient, causing thermal stress problems.

[0004] At present, there have also been some improved solutions for hot spot heat dissipation in the industry. Some adopt a single impinging jet structure. For example, the invention patent with the application number 2022108175973 discloses a double-layer microchannel heat dissipation structure for non-uniform heat sources, including a jet layer and a vein-type microchannel layer. The vein-type microchannel layer is arranged at the bottom of the jet layer. The vein-type microchannel layer is plate-shaped, and several microchannels are arranged on its top surface, and turbulators are arranged in the microchannels. Although jet heat dissipation can enhance local heat transfer, the fluid dispersion effect after jetting leads to a rapid decay of the heat transfer efficiency, and it is easy to form a flow dead zone on the chip surface. In addition, some use fin structures, but due to the short contact time between the fluid and the solid, it is difficult to fully achieve heat exchange. Therefore, in view of the deficiencies of existing radiators, this application proposes a brand-new solution, which can effectively solve the heat dissipation requirements for multiple hot spots. Summary of the Invention

[0005] The object of the present invention is to overcome the problems in the prior art that the temperature uniformity of the heat source surface is poor and the temperature gradient is too large, resulting in the degradation of chip performance and the shortening of service life. Here, the heat source surface refers to the heat source area containing multiple hot spots. The present application proposes a microchannel radiator that can improve heat dissipation uniformity and reduce the temperature gradient.

[0006] A hot spot refers to an area on the chip package where the heat concentration is significantly higher. The hot spot generates more heat than other areas on the chip, and the temperature distribution of the chip can be estimated through a power map.

[0007] The present invention is achieved through the following technical solutions:

[0008] A microchannel radiator for multiple hot spots includes a heat dissipation main body, a rectangular frame edge, and a jet inlet partition. The heat dissipation main body is arranged in the rectangular frame edge, and the jet inlet partition is arranged on the upper surface of the heat dissipation main body;

[0009] A jet heat exchange cavity is opened at the upper end of the heat dissipation main body. A jet liquid distribution plate is arranged at the upper end of the jet heat exchange cavity. Jet holes are opened on the jet liquid distribution plate. A jet liquid collection cavity is formed between the jet liquid distribution plate and the jet inlet partition. A jet inlet is opened on the jet inlet partition and is communicated with the jet liquid collection cavity. A jet area baffle is arranged at the lower end of the jet liquid distribution plate to partition the jet heat exchange cavity. Jet microchannels are opened at the lower ends of the side walls of the jet heat exchange cavity on both sides of the jet area baffle and are arranged outward. The outer ends of the jet microchannels on both sides are communicated with the liquid outlet cavity formed between the rectangular frame edge and the side wall of the heat dissipation main body. A confluence liquid outlet is opened on the rectangular frame edge and is communicated with the liquid outlet cavity;

[0010] Transverse microchannels are opened at the upper end of the heat dissipation main body and are arranged side by side and perpendicular to the jet microchannels. One end of the transverse microchannels is communicated with the liquid outlet cavity, and the other end is communicated with the transverse liquid collection cavity formed between the rectangular frame edge and the side wall of the heat dissipation main body. A transverse inlet is opened on the rectangular frame edge and is communicated with the transverse liquid collection cavity.

[0011] As a further setting of the above solution, the jet heat exchange cavity is of a rectangular structure, the width of which matches the width of the hot spot, and the length matches the length of the heat dissipation main body. Here, the structure is a choice for the matrix-distributed hot spots and is not specifically limited.

[0012] As a further setting of the above solution, there is one jet heat exchange chamber, which is opened in the central area where the hot spots are concentrated or on one side of the central area where the hot spots are concentrated. Here, the hot spots are distributed in an array or unevenly. The jet heat exchange chamber is arranged in the central area where the hot spots are concentrated or on one side of the central area where the hot spots are concentrated. For example, there are nine hot spots in the heat source area of the chip, which are distributed in an equidistant array of three rows and three columns. At this time, the jet heat exchange chamber is arranged above the middle row of hot spots or in the background area between two adjacent columns of hot spots.

[0013] As a further setting of the above solution, there are multiple jet heat exchange chambers, which are respectively opened in multiple different heat source areas of the discrete heat source. Here, the discrete heat source refers to the heat source area including multiple hot spots.

[0014] As a further setting of the above solution, multiple groups of jet holes are opened on the jet liquid distribution plate, and each group of jet holes is arranged in a rectangular array.

[0015] As a further setting of the above solution, the confluent outlet and the cross-flow inlet are respectively opened on two opposite side surfaces of the rectangular frame edge.

[0016] As a further setting of the above solution, the internal dimensions of the jet microchannel and the cross-flow microchannel are set to be the same, and fins are arranged in both the jet microchannel and the cross-flow microchannel.

[0017] As a further setting of the above solution, the multiple fins are arranged in parallel at intervals in the jet microchannel or the cross-flow microchannel, and the shape of the fin is any one of circular, square, triangular, trapezoidal or arc-shaped.

[0018] As a further setting of the above solution, a communication hole for connecting the jet microchannel and the cross-flow microchannel up and down is opened in the cross-region of the jet microchannel and the cross-flow microchannel.

[0019] As a further setting of the above solution, the heat dissipation main body, the rectangular frame edge and the jet inlet partition are integral components formed by any one of CNC machining, 3D printing, and metal welding.

[0020] Beneficial effects

[0021] The microchannel radiator disclosed by the present invention adopts a dual-inlet design, combines two heat exchange methods of jet cooling and cross-flow cooling, and improves the heat dissipation efficiency; through the jet liquid distribution plate and the jet area baffle, precise distribution of the fluid and targeted flow rate adjustment are realized, effectively improving the heat dissipation uniformity and temperature uniformity.

[0022] The microchannel heat sink disclosed by the present invention adopts an up-down layered design, with the jet microchannels and the cross-flow microchannels arranged on different layers respectively, avoiding the mutual interference between the flow channels. Meanwhile, fins are arranged in the microchannels to further enhance the heat transfer effect. Moreover, the position of the jet heat transfer cavity can be flexibly designed according to the actual heat source distribution, and the number of jet heat transfer cavities can be correspondingly designed according to the number of hot spots of the discrete heat source, enabling it to dissipate heat from multiple hot spot areas simultaneously, thereby improving the adaptability of the heat sink.

[0023] The microchannel heat sink in the present invention is also made by an integrated design and precision machining process, ensuring the reliability and machining accuracy of the product, and having good practicability and popularization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for describing the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 is the three-dimensional structure schematic diagram of Embodiment 1 of the present invention;

[0026] Figure 2 is the three-dimensional exploded structure schematic diagram of Embodiment 1 of the present invention;

[0027] Figure 3 is the three-dimensional structure schematic diagram of the heat dissipation main body, jet liquid distribution plate, and jet area baffle in Embodiment 1 of the present invention;

[0028] Figure 4 is the three-dimensional structure schematic diagram of the side-end cross-section of Embodiment 1 of the present invention;

[0029] Figure 5 is the side-view plane structure schematic diagram of Embodiment 1 of the present invention;

[0030] Figure 6 is Figure 5 the cross-sectional structure schematic diagram in the A-A direction of

[0031] Figure 7 is Figure 5 the cross-sectional structure schematic diagram in the B-B direction of

[0032] Figure 8 is the three-dimensional exploded structure schematic diagram of Embodiment 2 of the present invention;

[0033] Figure 9 is the structure schematic diagram of the jet heat transfer cavity corresponding to the chip hot spots in Embodiments 1 and 2;

[0034] Figure 10 Schematic diagram of the heat dissipation main body structure of Comparative Example 1;

[0035] Figure 11 Schematic diagram of the heat dissipation main body structure of Comparative Example 2;

[0036] Figure 12 Performance comparison of JI-CFHS radiator, CFHS radiator and PFHS radiator under different Reynolds numbers (1324 - 1986) in Comparative Experiment 1. The longitudinal indexes of each figure are respectively (a) the highest temperature on the heat source surface, (b) the maximum temperature difference on the heat source surface, (c) thermal resistance, and (d) performance coefficient;

[0037] Figure 13 Cloud diagram of the heat source surface of JI-CFHS radiator, CFHS radiator and PFHS radiator at Re = 1324 in Comparative Experiment 1;

[0038] Figure 14 Performance comparison of three radiators under different Reynolds numbers (1324 - 1986) in Comparative Experiment 1. The longitudinal indexes of each figure are respectively (a) temperature uniformity and (b) temperature gradient;

[0039] Figure 15 Performance comparison of two radiators under different Reynolds numbers in Comparative Experiment 2. The longitudinal indexes of each figure are respectively (a) the highest temperature on the heat source surface, (b) the maximum temperature difference on the heat source surface, and (c) thermal resistance;

[0040] Figure 16 Cloud diagram of the heat source surface of different radiators at Re = 1324 in Comparative Experiment 2;

[0041] Figure 17 Performance comparison of two radiators under different Reynolds numbers in Comparative Experiment 3. The longitudinal indexes of each figure are respectively (a) the highest temperature on the heat source surface, (b) the maximum temperature difference on the heat source surface, (c) thermal resistance, and (d) Nusselt number;

[0042] Figure 18 Cloud diagram of the heat source surface of different radiators at Re = 1324 in Comparative Experiment 3. Detailed implementation manners

[0043] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0044] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application may be combined with each other. The following will refer to the attached Figure 1-18 and describe the present application in detail in combination with the embodiments.

[0045] For the convenience of understanding, a chip with 9 hot spots is set as the processing object (as Figure 9 shown). The 9 hot spots are evenly distributed in an array with three horizontal and three vertical arrangements. The chip size is 10mm×10mm, the temperature at the hot spots of the chip is 80℃~85℃, and the refrigerant used during the test is a non-conductive liquid with a boiling point of 47℃; some settings in the following embodiments, such as the position and structure of the jet inlet, are set for the aforementioned multi-hot-spot chip. If the distribution position of the hot spots on the chip is adjusted, the position and structure of the jet inlet will be adjusted accordingly. Therefore, the following embodiments and comparative examples are only for the convenience of understanding and for facilitating comparative experiments to verify the effects of the corresponding set structures.

[0046] Embodiment 1

[0047] Embodiment 1 discloses a microchannel heat sink for multi-hot spots. Refer to the attached Figure 1 and the attached Figure 2 . Its main body part includes a heat dissipation main body 1, a rectangular frame edge 2, and a jet inlet partition plate 3. The rectangular frame edge 2 is a rectangular structure surrounded by four side cover plates. The heat dissipation main body 1 is integrally rectangular and is arranged inside the rectangular frame edge 2. Its lower surface is designed as a flat surface for direct contact with the heat source for heat exchange. The jet inlet partition plate 3 is attached to the upper surface of the heat dissipation main body 1.

[0048] A jet inlet 301 is opened at a position one-third of the length direction of the jet inlet partition plate 3. A cross-flow inlet 201 and a confluent outlet 202 are respectively opened on two opposite side surfaces of the rectangular frame edge 2, and the diameter of the confluent outlet 202 is larger than the diameter of the cross-flow inlet 201, so that the jet liquid and the cross-flow liquid can be discharged from the confluent outlet 202 simultaneously to take away the absorbed heat.

[0049] Refer to the attached Figures 3-7, on the upper surface of the heat dissipation main body 1 directly below the jet liquid inlet 301, a jet heat exchange cavity 101 is formed. The jet heat exchange cavity 101 is strip-shaped and parallel to one side of the heat dissipation main body 1, that is, corresponding to the background area between two adjacent columns of hot spots. At the same time, the lower end of the jet heat exchange cavity 101 extends downward to the bottom wall of the heat dissipation main body 1. Jet micro-channels 102 extending outward are formed at the lower ends of both side walls of the jet heat exchange cavity 101, and the outer ends of the jet micro-channels 102 on both sides are connected to the liquid outlet cavity 103 formed between the rectangular frame edge 2 and the side wall of the heat dissipation main body 1. A jet liquid distribution plate 4 is arranged at the top of the jet heat exchange cavity 101. Multiple groups of jet holes 401 arranged at intervals and in a rectangular array are formed on the jet liquid distribution plate 4. The lower surface area of the jet liquid inlet partition 3 corresponding to the jet liquid distribution plate 4 is recessed upward by a certain distance, so that when the jet liquid inlet partition 3 is attached to the upper surface of the heat dissipation main body 1, a corresponding jet liquid collection cavity 6 can be formed, and the jet liquid inlet 301 is connected to the jet liquid collection cavity 6. A jet area baffle 7 is arranged on the lower surface of the jet liquid distribution plate 4. The jet area baffle 7 is perpendicular to the jet micro-channel 102, so that under the blocking action of the jet area baffle 7, the jet heat exchange cavity 101 can be divided into two intervals, and the jet liquid in the two intervals respectively enters the corresponding jet micro-channels 102, enters the liquid outlet cavity 103 after passing through the jet micro-channels 102, and is finally discharged from the converging liquid outlet 202.

[0050] On the upper end of the heat dissipation main body 1, transverse flow micro-channels 104 arranged side by side are formed. The transverse flow micro-channels 104 are arranged parallel to the length direction of the jet heat exchange cavity 101 (that is, perpendicular to the direction of the jet micro-channel 102). One end of all the transverse flow micro-channels 104 is connected to the liquid outlet cavity 103, and the converging liquid outlet 202 is connected to the liquid outlet cavity 103. The other end of all the transverse flow micro-channels 104 communicates with a transverse flow liquid collection cavity 105 formed between the rectangular frame edge 2 and the side wall of the heat dissipation main body 1, and the transverse flow liquid inlet 201 is connected to the transverse flow liquid collection cavity 105.

[0051] Finally, in this Embodiment 1, fins 8 are also arranged in the jet micro-channels 102 and the transverse flow micro-channels 104. The internal dimensions of the jet micro-channels 102 and the transverse flow micro-channels 104 are kept the same. The fins 8 are arranged as cylinders, the diameter of which is smaller than the width of the jet micro-channels 102 and the transverse flow micro-channels 104, and the height of which is also smaller than the height of the two micro-channels. Specifically, when arranged, multiple fins 8 are distributed in parallel at intervals and are corresponding to the heat source hot spot area in terms of position.

[0052] In addition, it should be noted that the heat dissipation body 1, the rectangular frame edge 2, and the jet inlet liquid partition plate 3 in the first embodiment are formed into an integral component by means of precision CNC machining, 3D printing, metal welding, etc. Integral brazing processing can make the structure of the microchannel radiator more firm and reliable, and reduce the risks of secondary melting of the brazing filler metal and material degradation caused by secondary brazing. It can be integrally formed by 3D printing, and the structure of the welding surface can be optimized by machining and polishing. Since the microchannel radiator is an integral welding structure without multiple welding surfaces, it can effectively improve the strength of the radiator, and can sample and test the relevant performance of the radiator in a short time to achieve rapid iterative upgrading.

[0053] When the microchannel radiator disclosed in the first embodiment is in use, the heat source hot spot area of the heat generating device (such as a chip) is aligned with the jet heat exchange cavity 101 and is attached to the lower surface of the heat dissipation body 1. Then, the coolant is simultaneously introduced into the jet inlet 301 and the cross-flow inlet 201 respectively. The coolant entering from the jet inlet 301 first enters the jet liquid collecting cavity 6, is divided and sprayed into the bottom of the jet heat exchange cavity 101 through the jet holes 401 on the jet liquid dividing plate 4, and then is evenly divided by the jet area baffle 7 and flows outward along the corresponding jet microchannels 102 into the liquid outlet cavity 103, and finally is discharged from the confluent liquid outlet 202. The coolant entering from the cross-flow inlet 201 first enters the cross-flow liquid collecting cavity 105, then flows along the cross-flow liquid collecting cavity 105 into the liquid outlet cavity 103, and finally is also discharged from the confluent liquid outlet 202, making the internal liquid flow of the entire microchannel radiator present an asymmetric layout of two inlets and one outlet in a layered manner.

[0054] Comparative Example 1

[0055] Based on the first embodiment, as Figure 10 shown, two sets of upper and lower parallel rectangular microchannels 106 are arranged in the heat dissipation body 1, and the rectangular microchannels 106 have the same structure and distribution as the jet microchannels 102.

[0056] Control Group 2

[0057] Based on the second embodiment, as Figure 11 shown, a rectangular microchannel 107 is arranged in the upper part of the heat dissipation body 1, and a rectangular microchannel 108 is arranged in the vertical direction below the rectangular microchannel 107; the rectangular microchannel 107 and the rectangular microchannel 108 have the same structure and distribution as the jet microchannels 102.

[0058] Set up Comparative Experiment 1 to verify the heat dissipation effect of the radiator in Example 1. The radiator in Example 1 is an impinging jet - cross - flow microchannel radiator, that is, a JI - CFHS radiator; the radiator in Control Group 1 is a double - layer microchannel radiator, that is, a PFHS radiator; the radiator in Control Group 2 is a hybrid microchannel radiator, that is, a CFHS radiator.

[0059] Compare the performance of the three radiators at different Reynolds numbers (1324 - 1986). The results are as Figure 12 shown. As can be seen from Figure 12 (a) therein, the Tmax of the JI - CFHS radiator is significantly lower than that of the PFHS radiator and the CFHS radiator. This is attributed to the fact that the coolant jet inlet of the JI - CFHS is directly above the middle hot spot. After the jet, the coolant flows towards the two side hot spots, shortening the flow path of the lower - layer coolant. The fins in the hot - spot area can effectively exchange heat with the coolant.

[0060] As can be seen from Figure 12 (b) therein, the impinging jet - cross - flow (JI - CFHS) microchannel effectively reduces the temperature difference on the heat source surface. This is attributed to the inlet design of the array - type impinging jets in the middle of the JI - CFHS radiator, which effectively reduces the maximum temperature on the heat source surface and slows down the deterioration of heat transfer along the coolant flow direction. At the same time, it also avoids the sub - cooling at the cross - flow inlet of the JI - CFHS radiator.

[0061] As can be seen from Figure 12 (c) therein, as Re increases, the coolant flow rate increases and the thermal resistance decreases. The jet - cross - flow structure has the lowest thermal resistance and the best heat transfer ability.

[0062] As can be seen from Figure 12 (d) therein, the PEC of the JI - CFHS microchannel decreases with the increase of the Reynolds number. This is because with the change of the Reynolds number, the increase rate of the NU number of the JI - CFHS microchannel is less than the increase rate of the pressure difference. The PEC value of JI - CFHS increases by 51% - 56% compared with that of CFHS.

[0063] As can be seen from Figure 13 the content therein, in the cross - flow microchannel of the CFHS radiator and the co - flow microchannel of the PFHS radiator, the temperature on the heat source surface gradually increases along the fluid flow direction. The highest temperature of the PFHS radiator is near the three hot - spot positions at the fluid outlet (i.e., the right - most side), and the highest temperature of the CFHS radiator is located at the hot spot in the upper - right corner. This is because the hot spot in the upper - right corner is at the intersection of the outlets of the upper and lower layers;

[0064] The highest temperature points of the microchannel structure of the JI-CFHS radiator are located at three hot spots in the middle position. This is because the cold fluid impacts the solid-liquid interface in the form of a jet at the middle position, strengthening the local heat transfer performance. The fluid flowing through the hot spots on both sides is the combined action of the impinging jet in the lower layer and the cross-flow in the upper layer. The flow path of the fluid in the lower layer structure is shorter, effectively slowing down the increase in fluid temperature. Compared with the microchannels of the CFHS radiator and the PFHS radiator, the average temperature of the microchannel of the JI-CFHS radiator is relatively lower.

[0065] As can be seen from Figure 14 (a) among them, the temperature uniformity coefficients of the three radiators all decrease with the increase of the Reynolds number, indicating that the increase of the Reynolds number has a positive impact on the temperature uniformity. The temperature uniformity coefficient of the JI-CFHS radiator decreases the most with the increase of the Reynolds number, and the improvement effect of the Reynolds number on the temperature uniformity of the JI-CFHS radiator is the most obvious. The temperature uniformity coefficient of the JI-CFHS radiator is 16.94% - 19.41% lower than that of the CFHS radiator and 17.39% - 19.79% lower than that of the PFHS radiator. It shows that the hybrid structure design of jet impingement and cross-flow can effectively improve the temperature uniformity.

[0066] As can be seen from Figure 14 (b) among them, the maximum temperature gradient of the JI-CFHS decreases the most. The maximum temperature gradient of the JI-CFHS radiator is 10.74% - 14.38% lower than that of the CFHS radiator and 9.41% - 13.46% lower than that of the PFHS radiator.

[0067] Example 2

[0068] Example 2 discloses a microchannel radiator which is a further targeted improvement design based on the technical solution in Example 1, and the same parts as in Example 1 will not be described again.

[0069] The position of the jet heat exchange chamber 101 can be flexibly designed and adjusted according to the actual heat dissipation requirements. In this embodiment, it is set at the midpoint of the radiator length, that is, the central area where the hot spots are concentrated.

[0070] Set Comparative Experiment 2 to verify the influence of the jet inlet position on the heat dissipation performance. Select Example 1 and Example 2 for the comparative experiment. The correspondence between the jet heat exchange chamber and the hot spots is as Figure 9 shown. Example 2 corresponds to Figure 9 and Figure 15 Inlet1 in Figure 9 and Figure 15 . Example 1 corresponds to Figure 16 Inlet2 in

[0071] As can be seen from Figure 15As can be seen from Fig. (a), the maximum temperature Tmax at Inlet 2 is significantly lower than that at Inlet 1 where the jet inlet is located. In Example 2, the jet heat exchange cavity is directly above the middle hot spot, and the middle hot spot is in the stagnation zone of the jet. In Example 1, the jet heat exchange cavity is located in the middle position between two rows of hot spots, and the hot spot position is in the wall jet region. The impact of the wall jet on heat transfer in the wall jet region is less than that in the stagnation zone. However, a double-layer flow is superimposed above all the hot spots of the Inlet 2 structure, and the superimposed effect of the double-layer cross-flow and the wall jet region on temperature is greater than the heat transfer effect in the jet stop zone of Inlet 1.

[0072] From Figure 15 As can be seen from Fig. (b), Inlet 2 effectively reduces the temperature difference on the heat source surface. This is attributed to the JI-CFHS radiator impacting Inlet 2, effectively reducing the maximum temperature on the heat source surface and slowing down the deterioration of heat transfer along the coolant flow direction.

[0073] From Figure 15 As can be seen from Fig. (c), the thermal resistance of the Inlet 2 structure is lower than that of the Inlet 1 structure.

[0074] From Figure 16 It can be seen that the highest temperature point of Inlet 1 is located at the three hot spots in the middle position, while the highest temperature point of Inlet 2 is located at the hot spots far from the jet inlet. This is because the jet inlet is located in the middle position between two rows of hot spots. The hot spots close to the jet are affected by the superimposed effect of the wall flow of the jet and the double-layer cross-flow on heat dissipation, and the temperature is much lower than that of the hot spots directly facing the jet of Inlet 1. As the fluid flows, the temperature of the hot spots on the heat source surface gradually increases along the fluid flow direction, and the highest temperature is located at the hot spot in the lower right corner. This is because the hot spot in the lower right corner is located at the intersection of the outlets of the upper and lower layers. The heat exchange in the impinging jet-cross flow microchannel of Inlet 2 is more sufficient, and the temperature of the heat source surface in the impinging jet-cross flow microchannel of Inlet 2 is more uniform.

[0075] Due to the uneven and unpredictable distribution of the hot spot positions on the heat source surface, to improve the adaptability of the microchannel radiator, the jet heat exchange cavity 101 even adopts an adjustable design in practical applications. Specifically, when the heat source is concentrated in the central region, the jet heat exchange cavity 101 can be located at the center of the heat dissipation body 1 and symmetric jet zone baffles 7 are arranged; when the heat source is unevenly distributed, the jet heat exchange cavity 101 can be offset to the hot spot dense area, and at the same time, the jet zone baffles 7 adopt an asymmetric design; when there are multiple discrete hot spots, the jet heat exchange cavity 101 adopts a segmented design and is combined with the jet zone baffles 7 with multi-region independent control.

[0076] In addition, to ensure ideal heat dissipation at different positions, the jet liquid distribution plate 4 adopts a design with adjustable hole opening ratio, and the aperture distribution of the jet holes 401 is optimized according to the position of the heat exchange cavity to ensure flow uniformity; the jet microchannels 102 adopt the same rectangular cross-section design and the same interval positions to achieve the best fluid guiding effect. Through the above targeted optimization design in this Embodiment 2, various heat source distribution situations can be effectively dealt with to achieve the optimal heat dissipation effect.

[0077] A control group 3 is set up. On the basis of Embodiment 1, there is no jet area baffle on the lower surface of the jet liquid distribution plate 4, and the same parts as those in Embodiment 1 will not be described again.

[0078] A comparative experiment 3 is set up to verify the influence of the baffle setting on the heat dissipation performance. Embodiment 1 and the control group 3 are selected for the comparative test. Embodiment 1 corresponds to Figure 17 Baffled Structure in Figure 17 and the control group 3 corresponds to

[0079] From Figure 17 in (a), it can be seen that the Tmax of the JI-CFHS radiator with a baffle is significantly lower than that of the JI-CFHS radiator without a baffle. This is attributed to the fact that the baffle divides the impinging jet area into two independent sub-regions, controlling the fluid flow distribution on both sides. Due to the uneven distribution of hot spots on both sides, the fluid flow rate in the region with more hot spots is larger, resulting in a significant reduction in the temperature of the hot spots located downstream.

[0080] From Figure 17 in (b), it can be seen that the JI-CFHS microchannels with a baffle can more effectively reduce the temperature difference on the surface of the heat source. This is attributed to the fact that the baffle precisely controls the fluid flow distribution on both sides, effectively reducing the maximum temperature on the heat source surface and slowing down the deterioration of heat transfer along the coolant flow direction. At the same time, it also avoids the overcooling at the cross-flow inlet of the JI-CFHS radiator and raises the minimum temperature at the cross-flow inlet.

[0081] From Figure 17 in (c), it can be seen that the thermal resistance of the JI-CFHS radiator with a baffle is lower than that without a baffle. This is because the highest temperature on the heat source surface of the structure with a baffle is lower than that of the structure without a baffle.

[0082] From Figure 17 in (d), it can be seen that the average Nusselt number of the JI-CFHS radiator with a baffle is higher than that without a baffle.

[0083] From Figure 18 it can be seen that the temperature of the highest heat source surface of the structure with a baffle is lower, and the area of the high-temperature region is much smaller than that of the structure without a baffle.

[0084] Example 3

[0085] Example 3 discloses a microchannel heat sink that is further improved and designed based on the technical solution in Example 1. The similarities between it and Example 1 will not be described again.

[0086] In this embodiment 3, a number of connecting holes are arranged between the upper and lower corresponding jet microchannels 102 and the cross-flow microchannels 104, and the specific location, number and size of the connecting holes can be designed and adjusted according to the actual heat dissipation requirements. Specifically, the connecting holes are arranged in the area where the jet microchannel 102 and the cross-flow microchannel 104 intersect, so as to realize the fluid connection between the two independent liquid channel systems. When the local area of ​​the heat source is overheated, by adjusting the opening of the connecting holes, the coolant in part of the cross-flow microchannel 104 enters the jet microchannel 102 through the connecting holes, thereby enhancing the heat exchange effect of the local area. The number and distribution density of the connecting holes can be arranged in a targeted manner according to the temperature distribution of the heat source. Through the connection design of the cross-flow microchannel and the jet microchannel, this embodiment 3 can realize the complementary advantages of the two flow modes and further improve the heat exchange efficiency and temperature field uniformity of the radiator.

[0087] In addition, the fins 8 in this embodiment 3 can select different cross-sectional shapes according to actual heat dissipation requirements, including but not limited to square, triangle, trapezoid or arc. The setting of the fins 8 not only significantly increases the heat exchange area, but also can produce a turbulence effect during the fluid flow process, effectively breaking the fluid boundary layer and improving the convective heat transfer coefficient.

[0088] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microchannel heat sink for multiple hot spots, characterized in that: It includes a heat dissipation body, a rectangular frame edge and a jet liquid inlet baffle, wherein the heat dissipation body is arranged in the rectangular frame edge, and the jet liquid inlet baffle is arranged on the upper surface of the heat dissipation body; A jet heat exchange chamber is provided at the upper end of the heat dissipation body, a jet liquid separator plate is provided at the upper end of the jet heat exchange chamber, a jet hole is provided on the jet liquid separator plate, a jet liquid collecting chamber is formed between the jet liquid separator plate and the jet liquid inlet partition plate, a jet liquid inlet port connected to the jet liquid collecting chamber is provided on the jet liquid inlet partition plate, a jet zone baffle plate for separating the jet heat exchange chamber is provided at the lower end of the jet liquid separator plate, outwardly arranged jet microchannels are provided at the lower ends of the side walls of the jet heat exchange chamber on both sides of the jet zone baffle plate, and the outer ends of the jet microchannels on both sides are connected to the liquid outlet chamber; The upper end of the heat dissipation body is provided with a cross-flow microchannel arranged side by side and perpendicular to the jet microchannel, and the cross-flow microchannel and the jet microchannel are arranged in layers up and down, one end of the cross-flow microchannel is connected to the liquid outlet cavity, and the other end is connected to the cross-flow liquid collecting cavity; The liquid outlet cavity is formed by three side cover plates in the rectangular frame edge and three side surfaces of the heat dissipation body, and the outer ends of the jet microchannels on both sides are connected with two opposite ends in the liquid outlet cavity. The cross-flow liquid collection cavity is formed by another side cover plate in the rectangular frame edge and another side surface of the heat dissipation body. A cross-flow liquid inlet connected to the cross-flow liquid collection cavity is provided on the rectangular frame edge, and a converging liquid outlet connected to the liquid outlet cavity is provided on the rectangular frame edge.

2. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: The jet heat exchange cavity is provided with one, and is opened in the central area where the hot spots are concentrated or on one side of the central area where the hot spots are concentrated.

3. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: The jet heat exchange chamber is provided in plurality and is respectively opened in a plurality of different heat source areas of the discrete heat source.

4. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: The jet holes on the jet separation plate are provided with a plurality of groups, and each group of the jet holes is arranged in a rectangular array.

5. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: The converging liquid outlet and the cross-flow liquid inlet are respectively arranged on two opposite side surfaces of the rectangular frame.

6. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: The inner dimensions of the jet microchannel and the cross-flow microchannel are set to be the same, and fins are arranged in both the jet microchannel and the cross-flow microchannel.

7. The microchannel heat sink for multiple hot spots according to claim 6, characterized in that: A plurality of the fins are arranged in parallel and spaced apart in the jet microchannel or the cross-flow microchannel, and the shape of the fins is any one of circular, square, triangular, trapezoidal or arcuate.

8. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: A connecting hole for connecting the jet microchannel and the cross-flow microchannel up and down is provided in the intersection area of ​​the jet microchannel and the cross-flow microchannel.

9. The microchannel heat sink for multiple hot spots according to claim 1, characterized in that: The heat dissipation body, the rectangular frame edge and the jet liquid inlet baffle are integral components formed by any one of CNC machining, 3D printing and metal welding.

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