A dual-phase heat shock resistant and enhanced heat dissipation micro-channel heat sink

Abstract

This invention belongs to the field of chip heat dissipation and thermal management technology, specifically relating to a microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation, comprising a thermally conductive substrate and several heat sink blocks. The thermally conductive substrate has a mounting plane that fits against the heat-generating device; the heat sink blocks are located on the other side of the substrate, with a sealed cavities inside forming a hollow thin-walled thermal conductor, and fluid channels formed between adjacent heat sink blocks, through which a cooling fluid capable of gas-liquid phase change is introduced; the cavities are filled with a solid-liquid phase change material, forming a gas-liquid-solid-liquid dual-phase change coupling mechanism with the fluid. Under transient thermal shock, this heat sink rapidly buffers instantaneous heat and suppresses temperature spikes through the synergistic absorption of the latent heat of vaporization of the fluid and the latent heat of melting of the phase change material; under steady-state conditions, forced convection of the fluid continuously removes the heat stored in the phase change material, enhancing heat dissipation efficiency. This effectively solves the problems of insufficient thermal shock resistance and hysteresis response of traditional microchannel heat sinks, making it suitable for high-power chip heat dissipation.

Description

Technical Field

[0001] This invention belongs to the field of chip heat dissipation and thermal management technology, specifically relating to a microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation. Background Technology

[0002] With the rapid development of high-performance computing, artificial intelligence, and 5G / 6G communication technologies, the integration and power density of electronic chips are increasing exponentially. In applications such as server CPUs, GPUs, AI accelerator cards, and power semiconductor modules, chips often face severe transient thermal shocks during operation, which can lead to performance degradation and limit chip reliability and lifespan. Traditional heat dissipation solutions such as air cooling and heat pipes are limited by insufficient thermal inertia and are difficult to effectively cope with transient thermal shocks.

[0003] Among existing heat dissipation solutions, microchannel heat sinks have become one of the mainstream heat dissipation methods for high-power chips because they can bring the cooling medium close to the heat source and shorten the heat transfer path. However, traditional microchannel heat sinks rely on a stable flow state and cannot quickly absorb instantaneous heat under transient thermal shock, resulting in drastic temperature fluctuations in the chip and insufficient thermal shock resistance. Although some studies have attempted to introduce phase change materials for thermal buffering, they are mostly placed on the outer shell of the heat sink or in areas far from the heat source. Heat must travel a long conduction path to reach the phase change material, resulting in a delayed response and failing to achieve rapid buffering in the core area of ​​the heat source. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation, which enables heat to be directly transferred from the heat source to the phase change material and cooling fluid, significantly shortening the heat transfer path and improving the overall heat dissipation performance of the heat sink under transient and steady-state conditions.

[0005] The technical solution of this invention is: A two-phase change microchannel heat sink with enhanced thermal shock resistance and heat dissipation, used for heat dissipation of heat-generating devices, comprising: The thermally conductive substrate is made of thermally conductive material and has a mounting surface for close contact with the heat-generating device; Several heat dissipation blocks are arranged in a straight line on the side of the heat-conducting substrate away from the mounting plane and are fixed to the heat-conducting substrate. A sealed accommodating cavity is formed inside each heat dissipation block along its length. A gap is provided between two adjacent heat dissipation blocks to form a fluid channel arranged along the length of the heat dissipation block between two adjacent heat dissipation blocks. The fluid channel is used to introduce a cooling fluid that can undergo gas-liquid phase change. The cavity is filled with a phase change material capable of solid-liquid phase change. This phase change material is used to conduct heat with the cooling fluid flowing within the microchannel, forming a gas-liquid and solid-liquid dual phase change coupled heat transfer mechanism. Under steady-state conditions, the heat stored in the solid-liquid phase change material is efficiently carried away by the continuously flowing cooling fluid within the microchannel. Under transient thermal shock, the cooling fluid within the microchannel rapidly undergoes a gas-liquid phase change to absorb the first latent heat, while the solid-liquid phase change material within the heat sink simultaneously undergoes a solid-liquid phase change to absorb the second latent heat.

[0006] Preferably, the width of the fluid channel is 0.2 mm to 2 mm.

[0007] Preferably, the fluid channel is connected to an external circulation driver. The input end of the external circulation driver is connected to the outlet of the fluid channel, and the output end is connected to the inlet of the fluid channel. The external circulation driver is used to drive the fluid to circulate within the fluid channel. The external circulation driver includes, but is not limited to, a micro pump or a refrigeration cycler.

[0008] Preferably, the fluid channel is any one or a combination of a straight line, a tapering shape, a widening shape, or a sawtooth shape along its length.

[0009] Preferably, the cross-section of the accommodating cavity is any one of a rectangular ring, a trapezoidal ring, or a polygonal ring.

[0010] Preferably, a thermally conductive porous skeleton is provided inside the accommodating cavity. The thermally conductive porous skeleton is arranged along the length direction of the heat sink and has pores. The solid-liquid phase change material fills the pores of the thermally conductive porous skeleton.

[0011] Preferably, the pore size of the pores on the thermally conductive porous skeleton is from 10 µm to 500 µm.

[0012] Preferably, the thermally conductive porous framework is one of foamed metal or porous ceramic; the solid-liquid phase change material is any one of paraffin, fatty acid, hydrated salt or low-melting-point alloy.

[0013] Preferably, the cooling fluid flows in the same or opposite directions within adjacent microchannels.

[0014] Preferably, the cooling fluid is deionized water, refrigerant, or dielectric fluid, used to induce a gas-liquid phase change when flowing within the microchannel.

[0015] Compared with the prior art, the microchannel heat sink of the present invention, which has dual-phase change thermal shock resistance and enhanced heat dissipation, has the following beneficial effects: This invention directly encapsulates a phase change material capable of solid-liquid phase transition within a cavity inside a heat sink, placing the phase change material adjacent to the cooling fluid within the microchannel. This establishes a gas-liquid / solid-liquid dual phase change coupled heat transfer mechanism: Under transient thermal shock, the cooling fluid within the microchannel rapidly undergoes a gas-liquid phase transition to absorb the first latent heat, while simultaneously, the phase change material within the heat sink undergoes a solid-liquid phase transition to absorb the second latent heat. The synergistic effect of these two phase transitions effectively buffers the transient thermal load, significantly suppressing chip temperature spikes. This solves the problems of sluggish response and insufficient thermal shock resistance of traditional microchannel heat sinks under transient thermal shock. The problem is that, under steady-state conditions, the heat stored in the phase change material is efficiently carried away by the continuously flowing cooling fluid within the microchannels, achieving rapid heat dissipation and recycling of the phase change material, thus enhancing steady-state heat dissipation capabilities. Furthermore, this structure highly integrates heat storage and heat exchange functions within the heat sink, eliminating the need for additional heat sink volume. Heat is directly conducted from the heat source to the phase change material and cooling fluid, significantly shortening the heat transfer path and overcoming the response lag defect caused by the phase change material being placed far from the heat source in existing technologies. Overall, this improves the comprehensive heat dissipation performance of the heat sink under both transient and steady-state conditions. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention; Figure 2 The diagram shows different flow channel shapes, where a is a straight flow channel, b is a tapering flow channel, c is a widening flow channel, and d is a sawtooth flow channel. Figure 3 This is a schematic diagram of the cross-section of a hollow heat sink, where a is a rectangular ring and b is a trapezoidal ring.

[0017] Figure 4 for Figure 1 Schematic diagram of the phase change material in region A; Figure 5 This is a schematic diagram of fluid flow and the working state of the phase change material in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 100, Thermally conductive substrate; 200, Microchannel; 300, Heat sink; 310, Receptacle; 400, Phase change module; 410, Thermally conductive porous framework; 420, Solid-liquid phase change material. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0021] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0022] See Figures 1 to 5 As shown, in order to achieve direct heat transfer from the heat source to the phase change material and cooling fluid, shorten the heat transfer path, and improve the overall heat dissipation performance of the heat sink under transient and steady-state conditions, this embodiment provides a dual-phase change microchannel heat sink with thermal shock resistance and enhanced heat dissipation for heat dissipation of heat-generating devices. This embodiment mainly takes the heat dissipation scenario of high-power chips as an example. The device mainly includes a thermally conductive substrate, several heat sinks, and a phase change module disposed inside the heat sinks. The heat dissipation module includes a solid-liquid phase change material and a thermally conductive porous framework.

[0023] The thermally conductive substrate is made of a high thermal conductivity material such as aluminum or copper. It typically has a planar plate structure, with one side serving as a mounting surface for close contact with the heat-generating device. During use, it is tightly attached to the high-power chip and fixed using external components such as bolts. Several heat sinks are arranged in a straight line on the side of the thermally conductive substrate away from the mounting surface and are fixed to the substrate or integrally formed. A sealed accommodating cavity is formed within each heat sink along its length, creating a hollow, thin-walled thermally conductive body. Preferably, the material of the heat sinks is the same as that of the thermally conductive substrate. A preset spacing is provided between adjacent heat sinks to form a fluid channel along the length of the heat sink. A cooling fluid capable of undergoing a gas-liquid phase change is introduced into the fluid channel, which is circulated and supplied by an external refrigeration circulator. Preferably, the width of the fluid channel is 0.2 mm to 2 mm. Experiments show that when the channel width is less than 0.2 mm, the flow resistance increases sharply, and the pumping power consumption increases significantly. When the width is greater than 2 mm, the flow within the channel tends to be macroscopic, and the heat transfer advantage of the microchannel weakens. Within the range of 0.2 mm to 2 mm, the fluid is in the laminar transition zone or turbulent zone, which can effectively disrupt the thermal boundary layer and obtain a higher Nusselt number.

[0024] The cavity is filled with a phase change material capable of solid-liquid interaction. This phase change material conducts heat with the cooling fluid flowing within the microchannel, thus completing heat exchange and forming a gas-liquid / solid-liquid dual phase change coupled heat transfer mechanism. The cooling fluid is preferably deionized water, a refrigerant, or a dielectric fluid, which exchanges heat with the phase change material as it flows within the microchannel, causing a gas-liquid phase change.

[0025] Specifically, this invention directly encapsulates a phase change material capable of undergoing solid-liquid phase change within a cavity inside a heat sink, placing the phase change material adjacent to the cooling fluid within the microchannel. This constructs a gas-liquid / solid-liquid dual phase change coupled heat transfer mechanism: Under transient thermal shock, the cooling fluid within the microchannel rapidly undergoes a gas-liquid phase change to absorb the first latent heat, while simultaneously, the phase change material within the heat sink undergoes a solid-liquid phase change to absorb the second latent heat. The synergistic effect of these two phase changes effectively buffers the instantaneous thermal load, significantly suppressing chip temperature spikes and solving the problems of sluggish response and insufficient thermal shock resistance of traditional microchannel heat sinks under transient thermal shock. The problem is that, under steady-state conditions, the heat stored in the phase change material is efficiently carried away by the continuously flowing cooling fluid in the microchannel, realizing rapid heat dissipation and recycling of the phase change material, thus enhancing the steady-state heat dissipation capacity. In addition, this structure highly integrates the heat storage and heat exchange functions inside the heat sink, eliminating the need to increase the volume of the heat sink. Heat is directly conducted from the heat source to the phase change material and cooling fluid, significantly shortening the heat transfer path and overcoming the response lag defect caused by the phase change material being placed far from the heat source in the prior art. Overall, it improves the comprehensive heat dissipation performance of the heat sink under transient and steady-state conditions.

[0026] See Figure 2 As shown, the fluid channel can be any one or a combination of straight, tapering, expanding, or serrated shapes along its length. Straight channels are suitable for scenarios requiring uniform heat dissipation; tapering channels have a gradually decreasing cross-section, which accelerates the fluid and enhances convective heat transfer; expanding channels have a gradually increasing cross-section, which decelerates the fluid and reduces flow resistance; serrated channels generate centrifugal force through curved flow, inducing vortices and enhancing heat transfer.

[0027] See Figure 3 As shown, the cross-section of the accommodating cavity can be any one of a rectangular ring, a trapezoidal ring, or a polygonal ring. The rectangular ring has a relatively uniform heat flux density distribution and a flat wall surface, which is convenient for integral processing by extrusion molding or precision milling, resulting in lower costs. The trapezoidal ring has a larger heat exchange contact area on its sloping wall surface compared to a rectangular ring of the same height, and it helps to guide heat to be conducted along the sloping direction to the depth of the accommodating cavity, reducing local heat accumulation.

[0028] See Figure 1 and Figure 4As shown, a thermally conductive porous framework is disposed within the accommodating cavity. The thermally conductive porous framework is a structure with pores arranged along the length of the heat sink, and the pore diameter is preferably between 10 µm and 500 µm. The solid-liquid phase change material is filled into the pores of the thermally conductive porous framework. Experiments have shown that when the pore diameter is less than 10 µm, the pores are too small, and the flow resistance of the phase change material in the liquid state increases significantly. It is difficult to completely fill to the depth of the pores during vacuum infusion, which easily leads to insufficient filling or residual air bubbles. When the pore diameter is greater than 500 µm, the pores are too large, and the mechanical strength of the thermally conductive porous framework decreases, making it prone to structural damage when the phase change material expands in volume.

[0029] Furthermore, the thermally conductive porous framework is either foamed metal or porous ceramic. Among them, foamed metal has the best thermal conductivity and is suitable for high heat flux density and rapid charge and discharge scenarios, but attention should be paid to oxidation at high temperatures; porous ceramic has good thermal stability and is suitable for high temperature or corrosive environments, but it is more brittle and should be protected from severe mechanical impact.

[0030] Furthermore, the solid-liquid phase change material is any one of paraffin, fatty acids, hydrated salts, or low-melting-point alloys. Among them, paraffin is the most commonly used PCM in the field of chip heat dissipation and is suitable for most commercial applications; fatty acids are environmentally friendly and bio-based, and are suitable for medical or wearable electronic devices; hydrated salts have high latent heat and low cost, and are suitable for large-scale industrial applications; low-melting-point alloys have a thermal conductivity more than 100 times that of organic PCMs, have extremely fast response, but low latent heat, and are suitable for protection against millisecond-level extreme thermal shocks.

[0031] See Figure 5 As shown, the cooling fluid flows in the adjacent microchannels in the same or opposite directions. When the directions are the same, the inlet and outlet of all channels are located on the same side, simplifying the piping layout; when the directions are opposite, it is beneficial to improve temperature uniformity and heat exchange efficiency.

[0032] The working process of this invention: Reference Figure 5 As shown, in this embodiment, all microchannels are circulated with a cooling fluid of the same temperature (e.g., deionized water at 40°C), and all fluids flow in the same direction. Figure 5 (Indicated by the solid arrow). The bottom surface of the thermally conductive substrate is in direct contact with the high-power chip. The heat generated by the chip during operation is transferred through the substrate (…). Figure 5 The fluid (in the direction indicated by the hollow arrow) is conducted to the heat sink and the microchannels.

[0033] Steady-state operation: The heat generation rate of the chip reaches equilibrium with the heat carried away by the fluid, the paraffin inside the heat sink remains in a solid or partially melted state, and the system operates stably.

[0034] Transient thermal shock conditions: When the chip experiences a momentary power peak, it instantly generates a large amount of heat. The heat is first conducted to the inner wall of the microchannel, causing the wall temperature to rise rapidly. This triggers a boiling phase change in the fluid within the microchannel, where the fluid vaporizes and absorbs latent heat; this is the first stage of thermal buffering.

[0035] Simultaneously, heat is conducted from the heat sink wall to the cavity and then to the paraffin. When the temperature exceeds 55°C, the paraffin melts and absorbs the latent heat of the solid-liquid phase transition, forming a second thermal buffer. The two phase transition mechanisms work together to absorb instantaneous heat, effectively suppressing a rapid rise in chip temperature.

[0036] After the thermal shock subsides: As the chip power returns to normal levels, the heatsink temperature gradually decreases. When the temperature drops below 55°C, the paraffin wax begins to solidify, releasing the latent heat stored previously. This heat is carried away by the fluid flowing through the microchannels, completing the final heat dissipation.

[0037] Through this synergistic coupling of gas-liquid phase change and solid-liquid phase change, the microchannel heat sink in this embodiment can suppress chip temperature spikes within a safe range under transient thermal shock, and its thermal shock resistance is significantly improved compared with traditional microchannel heat sinks.

[0038] In summary, the present invention has the following technical advantages: 1. Excellent thermal shock resistance: The invention constructs a dual thermal buffer mechanism by synergistically coupling the gas-liquid phase change of the fluid within the microchannel with the solid-liquid phase change of the phase change material within the heat sink. Under transient thermal shock, the latent heat of the two phase changes superimposes to absorb instantaneous heat, effectively suppressing chip temperature spikes and significantly improving the thermal shock resistance of the heat sink.

[0039] 2. Steady-state enhanced heat dissipation: Under steady-state conditions, the forced convection of fluid within the microchannels works in conjunction with the heat storage and release of the phase change material within the heat sink. After the phase change material absorbs heat and melts, the continuous flow of fluid carries away the stored heat, keeping the phase change material in a state capable of absorbing heat and achieving efficient heat transfer and dissipation.

[0040] 3. Compact structure and high versatility: By utilizing the space of the heat sink as a container for the phase change material, a high degree of integration of heat storage and heat exchange functions is achieved without increasing the volume. Furthermore, the core structure of this invention does not depend on a specific substrate shape or microchannel size, and the geometric parameters can be flexibly adjusted according to different application scenarios, thus having broad application prospects.

[0041] 4. Enhanced dynamic performance: It can effectively smooth out periodic or pulsed thermal loads and reduce temperature fluctuations of the controlled object, which has extremely high application value for high-precision chips that require stable operating temperatures.

[0042] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A two-phase change microchannel heat sink with thermal shock resistance and enhanced heat dissipation, used for heat dissipation of heat-generating devices, characterized in that, include: The thermally conductive substrate is made of thermally conductive material and has a mounting surface for close contact with the heat-generating device; Several heat dissipation blocks are arranged in a straight line on the side of the heat-conducting substrate away from the mounting plane and are fixed to the heat-conducting substrate. A sealed accommodating cavity is formed inside each heat dissipation block along its length. A gap is provided between two adjacent heat dissipation blocks to form a fluid channel arranged along the length of the heat dissipation block between two adjacent heat dissipation blocks. The fluid channel is used to introduce a cooling fluid that can undergo gas-liquid phase change. The cavity is filled with a phase change material capable of solid-liquid phase change. This phase change material is used to conduct heat with the cooling fluid flowing within the microchannel, forming a gas-liquid and solid-liquid dual phase change coupled heat transfer mechanism. Under steady-state conditions, the heat stored in the solid-liquid phase change material is efficiently carried away by the continuously flowing cooling fluid within the microchannel. Under transient thermal shock, the cooling fluid within the microchannel rapidly undergoes a gas-liquid phase change to absorb the first latent heat, while the solid-liquid phase change material within the heat sink simultaneously undergoes a solid-liquid phase change to absorb the second latent heat.

2. The microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 1, characterized in that, The width of the fluid channel is 0.2 mm to 2 mm.

3. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 2, characterized in that, The fluid channel is connected to an external circulation driver. The input end of the external circulation driver is connected to the outlet of the fluid channel, and the output end is connected to the inlet of the fluid channel. It is used to drive the fluid to circulate within the fluid channel. The external circulation driver includes, but is not limited to, a micro pump or a refrigeration cycler.

4. The microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 1, characterized in that, The fluid channel is any one or a combination of a straight line, a tapering shape, a widening shape, or a sawtooth shape along its length.

5. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 1, characterized in that, The cross-section of the accommodating cavity is any one of a rectangular ring, a trapezoidal ring, or a polygonal ring.

6. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 1, characterized in that, A thermally conductive porous skeleton is provided inside the accommodating cavity. The thermally conductive porous skeleton is arranged along the length direction of the heat sink and has pores. The solid-liquid phase change material fills the pores of the thermally conductive porous skeleton.

7. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 6, characterized in that, The pore size on the thermally conductive porous framework is from 10 µm to 500 µm.

8. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 7, characterized in that, The thermally conductive porous framework is one of foamed metal or porous ceramic; the solid-liquid phase change material is any one of paraffin, fatty acid, hydrated salt or low-melting-point alloy.

9. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to claim 1, characterized in that, The cooling fluid flows in the same or opposite directions within adjacent microchannels.

10. A microchannel heat sink with dual-phase change thermal shock resistance and enhanced heat dissipation according to any one of claims 1-9, characterized in that, The cooling fluid is deionized water, refrigerant, or dielectric fluid, used to induce a gas-liquid phase change when flowing within the microchannel.

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