A manifold radiator based on regulating internal structure morphology and a manufacturing method thereof

Abstract

The application discloses a manifold radiator based on regulation of internal structure morphology and a manufacturing method thereof, and belongs to the technical field of electronic cooling and thermal management. The manifold radiator is composed of a base, a packaging cover plate and a flexible partition plate. The internal flow channel of the base is divided into a central thermal flow channel and a side flow channel by the flexible partition plate. The uniform flow of a working medium is realized through a fluid equalization structure. The flexible partition plate is a composite plate composed of a spring steel belt and a NiTi thin belt. The flexible partition plate can change the width of the flow channel with temperature change, and realizes the on-demand distribution of the cooling working medium. During manufacturing, the base is processed by using oxygen-free copper. The spring steel belt is processed by gradient micro-ribs, and the NiTi thin belt is pre-stretched and trained before being compounded. The manifold radiator is manufactured through assembly, packaging and testing. The manifold radiator breaks through the limitation of traditional static structure, can adaptively adjust heat dissipation, and improves the anti-dry burning capacity.

Description

Technical Field

[0001] This invention relates to the field of electronic cooling and thermal management technology, and more specifically, to a manifold heat sink based on the regulation of its internal structural morphology and its manufacturing method. Background Technology

[0002] As the power density of electronic chips continues to increase, the problem of local hot spots is becoming increasingly prominent.

[0003] Traditional microchannel heat sinks typically employ a static topology, meaning that once fabricated, the channel width and distribution remain fixed. However, the heat flux density distribution of a chip during actual operation is often dynamically changing. Heat sinks with fixed structures struggle to maintain optimal heat exchange efficiency under different operating conditions and cannot provide targeted, enhanced cooling for sudden localized high temperatures.

[0004] Existing active control schemes are often complex in structure and require external energy to drive, which reduces system reliability and cannot effectively cope with these uncertain operating conditions, leading to decreased local heat exchange efficiency, hot spot accumulation, and deterioration of system stability. There is an urgent need for a structural radiator with adaptive adjustment capabilities to improve heat dissipation efficiency and system reliability. Summary of the Invention

[0005] Based on the above-mentioned technical problems, this invention proposes a manifold radiator based on the regulation of internal structural morphology and its manufacturing method.

[0006] A manifold radiator based on regulating the internal structural morphology, comprising: The substrate has a flow channel, and the flow channel has a plurality of evenly spaced flexible baffles. The flexible baffles divide the flow channel into three parallel microchannels. The three microchannels include a central hot runner located in the middle and side flow channels located on both sides thereon. A sealing cover is fixed above the substrate and hermetically sealed with the substrate; The fluid equalization structure includes an inlet flow equalization channel connected to an inlet manifold and an outlet flow equalization channel connected to an outlet manifold. The inlet flow equalization channel and the outlet flow equalization channel are respectively located on the outer sides of both ends of the flow channel. The inlet flow equalization channel and the outlet flow equalization channel are respectively in fluid communication with the port channels at both ends of the microchannel. The flexible partition is a composite flexible plate composed of an elastic substrate layer and a shape memory alloy actuation layer, wherein the shape memory alloy actuation layer is located on the side of the flexible partition facing the central hot runner. In the case of low temperature, the flexible partition remains flat; in the case of high temperature, the shape memory alloy actuation layer undergoes phase change and shrinks, overcoming the resistance of the elastic substrate layer and causing the flexible partition to bend and deform away from the central hot runner.

[0007] Preferably, the substrate is made of a metal material with high thermal conductivity, and the two ends of the flow channel are provided with micro positioning slots distributed in a transverse direction. The two ends of the flexible partition are inserted into and fixed in the micro positioning slots.

[0008] Preferably, the elastic substrate layer is made of spring steel strip, and preferably a spring steel strip with a thickness of 130 μm; the shape memory alloy actuation layer is made of NiTi thin strip that has been pre-stretched and is in a martensitic pre-strained state, and the thickness of the NiTi thin film is 70 μm.

[0009] Preferably, the initial design width of the side flow channel is matched with the maximum lateral bending deflection of the flexible partition at the end temperature of the austenitic phase transformation, so that the remaining gap after the side flow channel is compressed is less than 5% of the initial width at high temperature, forming a near-zero flow cross section.

[0010] Preferably, the surface of the elastic substrate layer facing the fluid side is constructed with a gradient capillary flow guiding microrib array extending along the main flow direction of the fluid; the width of the microribs in the gradient capillary flow guiding microrib array gradually decreases along the direction gradually away from the heat source.

[0011] A method for manufacturing a manifold radiator based on regulating its internal structural morphology is as follows: (a) Select a metal material with high thermal conductivity as the heat sink substrate and use a CNC machining center to construct the flow channel; at both ends of the flow channel, use micro-electrical discharge machining technology to process vertical micro positioning slots in the middle of the adjacent port channels. (b) A spring steel strip with a gradient capillary microrib array is selected as the elastic substrate layer, and a NiTi thin strip that has been pre-stretched and is in a martensitic pre-strain state is selected as the shape memory alloy actuation layer. Under the constraint of a special fixture, the shape memory alloy actuation layer and the elastic substrate layer are combined with structural adhesive and cured under a low-temperature curing process to obtain a flexible partition. (c) Precision assembly: With the shape memory alloy actuation layer of the composite flexible partition facing the direction of the central hot runner, the end of the partition is precisely inserted into the two micro positioning slots that are directly opposite each other at both ends of the substrate using a micro-manipulation platform; a high-temperature resistant epoxy resin adhesive is applied to the gap at the root of the micro positioning slots using a micro-dispensing system and cured to achieve end anchoring. (d) Packaging test: The packaging cover is attached to the substrate and hermetically sealed; the test circuit is connected to perform fluid pressure resistance test and thermal load response verification.

[0012] Preferably, in step (b), the pre-stretching training process of the shape memory alloy actuation layer is as follows: First, the NiTi strip is fixed in a precision mold, annealed in a vacuum environment at 500℃ for 20 minutes and then water-quenched to remember its original shrinkage length. Subsequently, in a low-temperature environment below its martensite end temperature, an axial tensile load was applied to the NiTi thin strip in the twinned martensite state, and the tensile strain was controlled to be 4%, so that the material underwent martensite detwinning and reorientation to obtain macroscopic pre-strain. Finally, while maintaining the pre-strained state, the composite material is cured at a temperature below the austenitic phase transformation initiation temperature of the shape memory alloy actuating layer and combined with the elastic substrate layer, thereby locking the shape memory potential energy into the composite structure.

[0013] Preferably, in step (a), the matrix material is oxygen-free copper C10100.

[0014] Preferably, in step (b), the process of constructing a gradient capillary flow-guiding microrib array on the surface of the elastic substrate layer is as follows: using ultrafast laser micro / nano processing technology, utilizing the cold ablation characteristics of ultrashort pulse lasers, by precisely controlling the energy density, pulse frequency and superposition rate of the laser beam and scanning path, the material is removed layer by layer on the surface of the elastic substrate. By continuously changing the etching depth and scanning spacing of the laser along the fluid flow direction, a gradient microchannel with a continuous aspect ratio can be integrally formed. Beneficial effects

[0015] 1. The heat sink fabricated in this invention breaks through the limitations of the static topology of traditional microchannel heat sinks. Utilizing the thermally induced phase change actuation characteristics of shape memory alloys (SMA) and the mechanical antagonism mechanism of the elastic substrate, a temperature-sensitive intelligent flexible flow channel is constructed. Under high-temperature conditions, the heat sink can automatically widen the central flow channel cross-section in the hot spot area, achieving on-demand distribution of the cooling medium and targeted enhanced cooling, effectively eliminating local hot spots and significantly reducing the temperature gradient on the chip surface. In low-temperature standby mode, the structure automatically resets, avoiding excessive flow waste and pump power loss, achieving high energy efficiency across the entire operating range. 2. By constructing a gradient capillary flow-guiding microrib array with geometrically gradual changes along the flow direction on the fluid-facing side of the composite flexible partition, a passive microfluidic circulation mechanism is established on the partition surface. Utilizing the strong capillary pressure difference generated by the narrow and deep microgrooves at the root, the liquid is actively drawn into the deep gaps prone to dry burning for rapid replenishment. At the same time, the wide and shallow divergent flow channels at the ends reduce flow resistance, induce smooth merging of bubbles, and allow them to desorb with the mainstream. This design effectively suppresses the instability of two-phase flow under high heat flux density and significantly improves the critical heat flux density threshold of the radiator. Attached Figure Description

[0016] Figure 1 A schematic diagram of the structure of the present invention is shown. Figure 1 ; Figure 2 A schematic diagram of the structure of the present invention is shown. Figure 2 ; Figure 3 A schematic diagram of the fluid homogeneous distribution structure is shown; Figure 4 The diagram shows the working fluid flow direction of the fluid-equal distribution structure at low temperature; Figure 5 The diagram shows the working fluid flow direction of the fluid-equal distribution structure at high temperature; In the attached diagram, 1 is the substrate, 2 is the encapsulation cover, 3 is the inlet manifold, 4 is the outlet manifold, 5 is the flow channel, 51 is the central hot runner, 52 is the side flow channel, 6 is the flexible partition, 7 is the inlet flow equalization channel, 8 is the outlet flow equalization channel, 9 is the port channel, and 10 is the miniature positioning slot. Detailed Implementation

[0017] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0018] like Figures 1-5 The diagram shows a manifold heat sink based on the regulation of internal structural morphology and its manufacturing method. The heat sink utilizes the thermal shrinkage effect of shape memory alloy material and the elastic recovery capability of the substrate to automatically adjust the width of the flow channel 5 according to the fluid temperature. Under high temperature conditions, it automatically widens the central hot flow channel 51 to increase the flow rate, and under low temperature conditions, it returns to its original shape, thereby achieving efficient and adaptive thermal management.

[0019] The heat sink structure is as follows: The substrate 1 is made of a high thermal conductivity metal material, such as oxygen-free copper C10100. It has a flow channel 5 inside, and multiple evenly spaced flexible baffles 6 are set in the flow channel 5. These flexible baffles 6 divide the flow channel 5 into three parallel microchannels, namely the central hot flow channel 51 located in the middle and the side flow channels 52 located on both sides. The two ends of the flow channel 5 are provided with micro positioning slots 10 distributed in the transverse direction to fix the two ends of the flexible baffles 6 and ensure the stability of the flexible baffles 6 in the flow channel 5.

[0020] The encapsulation cover 2 is fixed above the base 1 and is hermetically sealed with the base 1 to prevent leakage of the cooling working fluid and ensure the sealing of the internal flow channel 5 system of the heat sink.

[0021] The fluid equalization structure includes an inlet equalization channel 7 connecting the inlet manifold 3 and an outlet equalization channel 8 connecting the outlet manifold 4. They are respectively located on the outer sides of both ends of the flow channel 5. The inlet equalization channel 7 and the outlet equalization channel 8 are fluidly connected to the port channels 9 at both ends of the microchannel. Each microchannel has a port channel 9 at both ends, so that the cooling working fluid can flow into and out of the microchannel evenly, ensuring the uniformity of heat dissipation effect.

[0022] The flexible partition 6 is a composite flexible plate, composed of an elastic substrate layer and a shape memory alloy actuation layer. The elastic substrate layer uses spring steel strips, and its surface facing the fluid has a gradient capillary microrib array extending along the main flow direction of the fluid. The width of the microribs gradually decreases as they move away from the heat source. The shape memory alloy actuation layer uses NiTi thin strips that have undergone pre-stretching training and are in a martensitic pre-strain state, located on the side of the flexible partition 6 facing the central hot runner 51. In low-temperature conditions, i.e., when the fluid temperature is lower than the austenitic phase transformation initiation temperature of the shape memory alloy, for example, the initiation temperature is set to 50℃ ± At 2℃, the shape memory alloy actuation layer is in the twinned martensite phase. At this time, the geometry of the composite flexible partition 6 is dominated by the elastic substrate layer, maintaining a straight state under the action of the substrate stiffness. The central hot runner 51 and the side flow channels 52 both have a preset initial width, and the flow resistance is on the same order of magnitude. The cooling medium is distributed in the manifold according to the resistance and flows through all channels at the same time to achieve uniform heat dissipation with low power consumption. When the temperature rises and enters a high-temperature state, once the temperature exceeds the initial temperature and approaches the end temperature of the austenite phase transformation, such as 70℃ ± At 2℃, the shape memory alloy actuating layer undergoes a reverse phase transformation and recovers to the austenitic phase, generating phase transformation recovery stress. This stress overcomes the bending resistance of the outer elastic substrate, forcing the baffle to bend in an arc shape away from the central hot runner 51. At this time, the side flow channel 52 is compressed into an extremely narrow micro-slit with a width of less than 10μm, almost filled by the outward displacement of the flexible baffle 6, while the hydraulic diameter of the central hot runner 51 is significantly widened. The flow resistance difference is used to adaptively guide more cooling fluid to flow to the high-temperature core region to suppress the temperature rise. When the heat load is removed and the fluid temperature drops below the martensitic phase transformation end temperature of 40℃, the shape memory alloy actuating layer transforms back into martensite and softens. The baffle automatically returns to a straight state by relying on the elastic rebound force accumulated by the elastic substrate layer during the bending process, completing the working cycle.

[0023] In addition, the initial design width of the side flow channel 52 is matched with the maximum lateral bending deflection of the flexible baffle 6 at the end temperature of the austenitic phase transformation, so that the remaining gap after the side flow channel 52 is compressed at high temperature is less than 5% of the initial width, forming a near-zero flow section, which further enhances the control effect on the flow direction of the cooling medium.

[0024] A method for manufacturing a manifold radiator based on regulating its internal structural morphology includes the following steps: Step (a): Select a high thermal conductivity metal material (such as oxygen-free copper C10100) as the heat sink substrate 1, construct the flow channel 5 using a CNC machining center, and process vertical micro positioning slots 10 at the middle position of adjacent port channels 9 using micro-electrical discharge machining technology at both ends of the flow channel 5 to provide positioning for the subsequent installation of the flexible partition 6.

[0025] Step (b): A spring steel strip with a gradient capillary microrib array is selected as the elastic substrate layer. This gradient capillary microrib array is fabricated using ultrafast laser micro / nano fabrication technology (femtosecond laser). Utilizing the cold ablation characteristics of ultrashort pulse lasers, the material is removed layer by layer from the surface of the elastic substrate by precisely controlling the energy density, pulse frequency, and superposition rate of the laser beam and scanning path. By continuously changing the etching depth and scanning spacing along the fluid flow direction, a gradient microchannel with a continuously varying aspect ratio is integrally formed. Furthermore, the laser-induced surface nano-strip structure can further enhance the surface's superhydrophilicity. A NiTi thin strip that has undergone pre-stretch training and is in a martensitic pre-strain state is selected as the shape memory alloy actuation layer. In step (b), structurally, the gradient microchannels evolve gradually from the root to the top of the flexible partition 6: in the root region near the heat source, the microchannel structure is densely packed and forms a narrow and deep structure, for example, with a channel width of 20-30 μm and a depth-to-width ratio >2:1, creating a strong capillary potential energy region. This utilizes the high capillary pressure difference to actively draw the cooling medium into the root gap, which is prone to dry burning, to achieve rapid liquid replenishment. As the flow transitions towards the top, away from the heat source, the microchannel structure gradually widens and becomes shallower, with the channel width exceeding 100 μm, forming a divergent, low-resistance channel. This facilitates the smooth merging of bubbles in this region and their rapid detachment from the surface along with the main flow. This structural gradient establishes a passive microfluidic circulation mechanism on the partition surface, achieving directional liquid supply and efficient bubble removal. In step (b), the pre-stretching training process is as follows: First, the NiTi thin strip is fixed in a precision mold, annealed for 20 minutes in a vacuum environment at 500°C, and then water-quenched to memorize its original shrinkage length; then, in a low-temperature environment below its martensite end temperature, an axial tensile load is applied to the NiTi thin strip in the twinned martensite state, and the tensile strain is controlled to be 4%, so that the material undergoes martensite detwinning and reorientation to obtain macroscopic pre-strain; finally, under the condition of maintaining this pre-strain state, and below the austenitic phase transformation start temperature of the shape memory alloy actuating layer, the shape memory alloy actuating layer is composited with the elastic substrate layer using a structural adhesive, and cured under a low-temperature curing process to obtain the flexible partition 6.

[0026] Step (c): Perform precision assembly. With the shape memory alloy actuation layer side of the composite flexible partition 6 facing the direction of the central hot runner 51, use a micro-manipulation platform to precisely insert the end of the partition into the two micro positioning slots 10 that are directly opposite each other at both ends of the substrate 1; use a micro-dispensing system to apply high-temperature resistant epoxy resin adhesive to the gap at the root of the micro positioning slots 10 and cure it to achieve end anchoring and ensure that the flexible partition 6 is firmly installed. In step (c), the amount of adhesive is strictly controlled to prevent the adhesive from climbing to the effective active area in the upper part of the flexible partition 6 through capillary action. Heating is used to cure the adhesive, so as to achieve a firm anchorage at the root of the flexible partition 6, while retaining the free bending ability of its main body.

[0027] Step (d): Complete the encapsulation test by attaching the encapsulation cover 2 to the substrate 1 and performing hermetically sealed encapsulation; connect the test circuit to perform fluid pressure resistance test and thermal load response verification to ensure that the heat sink performance meets the design requirements.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A manifold radiator based on regulating the internal structural morphology, characterized in that, include: The substrate (1) has a flow channel (5) inside, and the flow channel (5) has a plurality of evenly spaced flexible partitions (6) inside. The flexible partitions (6) divide the flow channel (5) into three parallel microchannels. The three microchannels include a central hot runner (51) located in the middle and side flow channels (52) located on both sides of it. The encapsulation cover (2) is fixed above the substrate (1) and hermetically encapsulated with the substrate (1); The fluid equalization structure includes an inlet equalization channel (7) connecting the inlet manifold (3) and an outlet equalization channel (8) connecting the outlet manifold (4). The inlet equalization channel (7) and the outlet equalization channel (8) are respectively located on the outer sides of both ends of the flow channel (5). The inlet equalization channel (7) and the outlet equalization channel (8) are respectively in fluid communication with the port channels (9) at both ends of the microchannel. The flexible partition (6) is a composite flexible plate composed of an elastic substrate layer and a shape memory alloy actuation layer, wherein the shape memory alloy actuation layer is located on the side of the flexible partition (6) facing the central hot runner (51); In the case of low temperature, the flexible partition (6) remains flat; in the case of high temperature, the shape memory alloy actuation layer undergoes phase change shrinkage, which overcomes the resistance of the elastic substrate layer and causes the flexible partition (6) to bend and deform away from the central hot runner (51).

2. The manifold radiator based on adjustable internal structural morphology according to claim 1, characterized in that, The substrate (1) is made of a metal material with high thermal conductivity. The flow channel (5) has micro positioning slots (10) distributed laterally at both ends. The two ends of the flexible partition (6) are inserted into and fixed in the micro positioning slots (10).

3. The manifold radiator based on adjustable internal structural morphology according to claim 1, characterized in that, The elastic substrate layer is made of spring steel strip; the shape memory alloy actuation layer is made of NiTi thin strip that has undergone pre-stretch training and is in a martensitic pre-strain state.

4. The manifold radiator based on adjustable internal structural morphology according to claim 1, characterized in that, The initial design width of the side flow channel (52) matches the maximum lateral bending deflection of the flexible partition (6) at the end temperature of the austenitic phase transformation, so that the remaining gap after the side flow channel (52) is compressed is less than 5% of the initial width at high temperature, forming a near-zero flow cross section.

5. The manifold radiator based on adjustable internal structural morphology according to claim 1, characterized in that, The surface of the elastic substrate facing the fluid side is constructed with a gradient capillary flow guiding microrib array extending along the main flow direction of the fluid; along the direction gradually away from the heat source, the width of the microribs in the gradient capillary flow guiding microrib array gradually decreases.

6. The method for manufacturing a manifold radiator based on the control of internal structural morphology as described in any one of claims 1 to 5, characterized in that, The method is as follows: (a) Select a metal material with high thermal conductivity as the heat sink substrate (1) and use a CNC machining center to construct the flow channel (5); at both ends of the flow channel (5), use micro-electrical discharge machining technology to process vertical micro positioning slots (10) in the middle of adjacent port channels (9). (b) A spring steel strip with a gradient capillary microrib array is selected as the elastic substrate layer, and a NiTi thin strip that has been pre-stretched and is in a martensitic pre-strain state is selected as the shape memory alloy actuation layer. Under the constraint of a special fixture, the shape memory alloy actuation layer and the elastic substrate layer are combined using a structural adhesive and cured under a low-temperature curing process to obtain a flexible partition (6). (c) Precision assembly: With the shape memory alloy actuation layer side of the composite flexible partition (6) facing the direction of the central hot runner (51), the end of the partition is precisely inserted into the two micro positioning slots (10) that are directly opposite each other at both ends of the substrate (1) using a micro-manipulation platform; high-temperature resistant epoxy resin adhesive is applied to the gap at the root of the micro positioning slot (10) using a micro-dispensing system and cured to achieve end anchoring; (d) Packaging test: The packaging cover (2) is attached to the substrate (1) and hermetically sealed; the test circuit is connected to perform fluid pressure resistance test and thermal load response verification.

7. The method for manufacturing a manifold radiator based on regulating the internal structural morphology as described in claim 6, characterized in that, In step (b), the pre-stretching training process of the shape memory alloy actuation layer is as follows: First, the NiTi strip is fixed in a precision mold, annealed in a vacuum environment at 500℃ for 20 minutes and then water-quenched to remember its original shrinkage length. Subsequently, in a low-temperature environment below its martensite end temperature, an axial tensile load was applied to the NiTi thin strip in the twinned martensite state, and the tensile strain was controlled to be 4%, so that the material underwent martensite detwinning and reorientation to obtain macroscopic pre-strain. Finally, while maintaining the pre-strained state, the composite material is cured at a temperature below the austenitic phase transformation initiation temperature of the shape memory alloy actuating layer and combined with the elastic substrate layer, thereby locking the shape memory potential energy into the composite structure.

8. The method for manufacturing a manifold radiator based on regulating the internal structural morphology as described in claim 6, characterized in that, In step (a), the substrate (1) material is selected as oxygen-free copper C10100.

9. The method for manufacturing a manifold radiator based on regulating the internal structural morphology as described in claim 6, characterized in that, In step (b), the process of constructing a gradient capillary flow-guiding microrib array on the surface of the elastic substrate layer is as follows: using ultrafast laser micro / nano processing technology, utilizing the cold ablation characteristics of ultrashort pulse lasers, by precisely controlling the energy density, pulse frequency and superposition rate of the laser beam and scanning path, the material is removed layer by layer on the surface of the elastic substrate. By continuously changing the etching depth and scanning spacing of the laser along the fluid flow direction, a gradient microchannel with a continuous aspect ratio can be integrally formed.

Images