A heat-driven high-efficiency phase-change heat sink, heat buffer system and heat buffer method

Abstract

The application discloses a heat-driven high-efficiency phase-change heat sink, a heat buffering system and a heat buffering method. The heat sink comprises a sealed shell, a solid-liquid phase-change material, a heat input wall surface, a periodic pointed fin row liquid discharge structure arranged on the inner side of the heat input wall surface, and a heat actuator array arranged along the circumference of the shell. The heat actuator comprises a sealed flexible cavity containing a gas-liquid phase-change working medium, a capillary transport structure and two side walls with different deformation capabilities. The gas-liquid phase-change working medium is evaporated by heat to drive the heat actuator to generate directional deformation and apply extrusion force to the solid phase-change material towards the heat exchange interface. The molten phase-change material migrates through the liquid discharge grooves between adjacent pointed fins. The application also discloses a heat buffering system and a method comprising the heat sink. The application utilizes heat input to realize self-driven pressure application and cooperates with the liquid discharge grooves to strengthen contact melting, and is suitable for transient heat buffering scenes such as high-power electronic devices, lasers, radar transmitting assemblies, pulse power equipment and battery systems.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology, specifically relating to a heat-driven high-efficiency phase change heat sink, thermal buffer system, and thermal buffering method. Background Technology

[0002] With the continuous increase in power density of high-power electronic devices, lasers, radar transmitting components, pulsed power equipment, and battery systems, the heat flux density generated by these devices in a short period of time has increased significantly. If this heat cannot be absorbed and buffered in time, it can easily lead to excessively rapid local temperature rise in the devices, thereby affecting their operational stability, service life, and safety. Heat sinks are thermal management components used to absorb, conduct, and temporarily store heat. They are typically placed between the heat source and the external heat dissipation system. When the heat source generates a transient thermal load, it first buffers the heat and then releases the absorbed heat through the subsequent heat dissipation process, thereby reducing the instantaneous temperature peak of the heat source.

[0003] Phase change heat sinks are an important type of heat sink structure. They utilize the characteristic of phase change materials to absorb a large amount of latent heat during the solid-liquid phase transition process, achieving efficient temporary storage of transient heat. Their basic working principle is as follows: When the heat source is operating, heat is transferred to the interior of the phase change heat sink through the heat input wall, causing the solid phase change material near the heat input wall to melt first. During melting, the phase change material slows down the temperature rise of the heat source by absorbing latent heat. When the heat load of the heat source decreases or external heat dissipation conditions recover, the phase change material releases the stored heat to the external heat dissipation structure and re-solidifies, thus restoring its heat buffering capacity. Therefore, phase change heat sinks are particularly suitable for operating conditions such as short-term high heat flux, intermittent heating, and pulsed heating.

[0004] During the operation of a phase change heat sink, the heat transfer state between the heat input wall and the solid phase change material directly determines its heat absorption rate. For phase change heat sinks with bottom or local wall heating, the ideal state is that the solid phase change material can remain close to the heat input wall and form a thin molten liquid film between them, allowing heat to be transferred to the solid-liquid phase change interface with low interfacial thermal resistance. This process can be characterized by contact melting. Contact melting can significantly improve the melting rate of the phase change material, but its enhancement effect depends on two key conditions: first, the solid phase change material needs to remain close to or pressed against the heat input wall to prevent the solid-liquid phase change interface from moving away from the heat source; second, the liquid phase change material generated by contact melting needs to be discharged from the heat exchange interface in a timely manner to prevent the liquid film from continuously thickening.

[0005] However, in practical phase change heat sinks, commonly used phase change materials such as paraffin wax generally suffer from problems such as low thermal conductivity, high molten liquid viscosity, and easy retention of liquid phase change materials near the heat input wall. As the melting process continues, liquid phase change materials gradually accumulate near the heat input wall, increasing the liquid film thickness and reducing the effective contact between the solid phase change material and the heat input wall. This leads to increased interfacial thermal resistance, decreased melting front advancement speed, and ultimately limits the heat absorption power density and transient thermal buffering capacity of the phase change heat sink.

[0006] Existing phase change heat sink solutions primarily improve upon external heat exchange paths, phase change material encapsulation methods, or overall thermal control system structures. For example, European patent EP2543950A2 discloses a phase change material heat sink comprising a sealed shell containing the phase change material and a fluid channel structure in thermal contact with the sealed shell. Heat input or output is achieved through heat exchange between the fluid channel and the phase change material cavity. While this type of solution can improve the heat exchange process between the phase change heat sink and the external heat exchange fluid, its main focus is on the external heat exchange path of the heat sink. It does not address the issues of increased interfacial thermal resistance caused by the solid phase change material gradually moving away from the heat input wall during melting, or by the liquid phase change material remaining at the heat input interface.

[0007] Chinese patent application CN114980667A discloses a passive thermal control system, which includes a boiling condensation heat transfer module, a phase change heat storage module, and a finned heat dissipation module. It achieves thermal control of a pulsed heat load source through rapid heat transfer, phase change heat storage, and natural dissipation. This type of solution focuses on constructing a system-level path for heat transfer, storage, and dissipation, which can improve the overall heat dissipation capacity of the thermal control system. However, regarding the contact melting process inside the phase change heat storage module, it still does not solve the problems of how the solid phase change material can continuously and actively approach the heat input wall within a sealed space, and how the molten phase change material can be promptly discharged from the heat exchange interface.

[0008] In their non-patent literature study, "Melt front visualization and flow prediction in dynamic phase change materials on finned heat sinks," Stavins et al. investigated the visualization of the melting front and flow prediction of dynamic phase change materials on finned heat sinks. They pointed out that discharging molten liquid and maintaining a thin molten layer under external force is a crucial factor in improving the heat transfer performance of dynamic phase change materials, and that the fin geometry affects the formation of the molten layer and the flow path. This study provides a basis for the geometric design of pointed fins and drainage channels in terms of heat transfer and flow. However, it did not propose utilizing the heat input itself to drive the force-applying structure within a sealed phase change heat sink, nor did it address the issues of solid phase change materials actively approaching the heat input wall and the coordinated discharge of molten phase change materials under various operating conditions.

[0009] Therefore, for phase change heat sinks operating under transient high heat flux density conditions, simply improving the overall heat transfer process through external fluid channels, external heat dissipation fins, or conventional encapsulation structures is insufficient to fully address the problem of heat absorption rate attenuation at the heat input interface. The core challenge lies in two aspects: on the one hand, the solid phase change material needs to continuously approach the heat input wall to maintain contact melting; on the other hand, the liquid phase change material generated by contact melting needs to be promptly removed from the heat exchange interface to reduce the liquid film thickness and lower the interfacial thermal resistance. How to simultaneously achieve active contact of the solid phase change material and effective drainage of the molten phase change material under sealed, compact, and multi-position operating conditions is a crucial problem that urgently needs to be solved to improve the transient heat absorption capacity of phase change heat sinks. Summary of the Invention

[0010] To address the problems of existing phase change heat sinks, such as the difficulty in maintaining solid phase change material (PCM) close to the heat input wall, the tendency of molten PCM to stagnate leading to liquid film thickening, increased interfacial thermal resistance, and complex external loading structures, this invention provides a heat-driven high-efficiency PCM heat sink, a heat buffer system, and a heat buffering method. The core concept lies in constructing a thermal actuator array driven by the heat input itself inside the sealed PCM heat sink, allowing this array to directly participate in the contact melting process of the PCM. The thermal actuators are not external loading components but rather self-driven force-applying structures integrated with the internal heat input process of the PCM heat sink. When the heat input wall receives heat from the heat source, the thermal actuators synchronously respond to the heat input and generate directional deformation, converting part of the thermal energy during the heat input process into mechanical extrusion force on the solid PCM, thereby actively pushing the solid PCM closer to the heat input wall. Thus, adaptive enhancement of the contact melting process can be achieved without additional external driving devices such as motors, cylinders, or hydraulic mechanisms.

[0011] To achieve the above objectives, the present invention adopts the following technical solution.

[0012] A heat-driven high-efficiency phase change heat sink includes: a sealed housing; a solid-liquid phase change material disposed within the sealed housing; a heat input wall for receiving heat from a component to be cooled; a thermal actuator array disposed within the sealed housing and thermally coupled to the heat input wall, wherein the thermal actuator array is arranged at circumferential intervals along the sealed housing; and a drain heat exchange structure disposed on the side of the heat input wall facing the solid-liquid phase change material.

[0013] Each thermal actuator in the thermal actuator array includes a sealed flexible cavity thermally coupled to the heat input wall and a force-applying end facing the solid-liquid phase change material. The sealed flexible cavity is configured to generate directional deformation when heated, so as to apply a compressive force towards the heat exchange interface to the solid-liquid phase change material through the force-applying end, causing the molten phase change material at the heat exchange interface to migrate towards the draining heat exchange structure. The draining heat exchange structure is located within the enclosed area of ​​the thermal actuator array and is used to migrate and guide the molten phase change material at the heat exchange interface away from the heat exchange interface.

[0014] Furthermore, the thermal actuator also includes a gas-liquid phase change working fluid contained in the sealed flexible cavity, and a capillary transport structure disposed on the inner wall of the sealed flexible cavity; when the heat input wall receives heat, the gas-liquid phase change working fluid is heated and evaporates, causing the sealed flexible cavity to undergo directional deformation; the capillary transport structure is used to realize the cyclic transport of the gas-liquid phase change working fluid.

[0015] Furthermore, the draining heat exchange structure includes multiple pointed fins, and periodic draining channels are formed between adjacent pointed fins for transporting molten phase change material; the molten phase change material at the heat exchange interface migrates along the periodic draining channels.

[0016] Furthermore, the sealed flexible cavity has a first sidewall and a second sidewall with different deformation capabilities. Due to the different equivalent stiffness and deformation response of the two sidewalls, when the pressure inside the cavity increases, the sealed flexible cavity can bend or deflect in a predetermined direction, causing the force-applying end of the thermal actuator to stably press against the solid phase change material. Through this asymmetric flexible deformation structure, the thermal actuator can directly couple the heat input process with the mechanical pressure application process, so that the phase change material is continuously subjected to a force towards the heat exchange interface during the heating and melting process.

[0017] Furthermore, the plurality of pointed fins are radially distributed along the heat input wall surface and / or periodically distributed along the circumference of the heat input wall surface; the periodic drainage grooves extend from the central region of the heat input wall surface to the outer peripheral region to migrate the liquid phase change material generated by contact melting at the heat exchange interface to the outer peripheral region, the liquid collection region or the low-resistance flow region, and prevent the liquid phase change material from being retained at the heat exchange interface.

[0018] Furthermore, the cross-section of the pointed fin is triangular, trapezoidal, arc-shaped pointed structure, or a combination thereof; the top of the pointed fin faces the solid phase change material, forming a local or near-contact heat exchange region with the solid phase change material under the extrusion of the thermal actuator; the two side walls of the pointed fin serve as guiding surfaces, guiding the liquid phase change material into adjacent periodic drainage channels. Through this structure, the molten phase change material near the heat input wall is less likely to remain for extended periods, thus reducing the liquid film thickness at the heat exchange interface.

[0019] Preferably, the inner wall of the periodic drainage groove is provided with a hydrophilic coating or hydrophilic microstructure to improve the ability of the liquid phase change material to migrate along the groove direction; the top of the pointed fin or the non-drainage area is provided with a hydrophobic coating to reduce the retention of the liquid phase change material at the heat exchange interface; through the synergistic cooperation between the hydrophilic drainage groove and the hydrophobic surface of the pointed fin, the thickness of the molten liquid film at the heat exchange interface is further reduced.

[0020] Furthermore, the solid-liquid phase change material is at least one of paraffin-based phase change materials, fatty acid-based phase change materials, salt hydrate-based phase change materials, low-melting-point metal or alloy-based phase change materials, and composite phase change materials; wherein the phase change temperature of the paraffin-based phase change material is 30°C to 80°C.

[0021] Preferably, when the solid-liquid phase change material is a paraffin-based phase change material, the groove depth of the periodic drainage groove is 0.8 mm to 4.0 mm, the periodic distance between adjacent pointed fins is 1.5 mm to 6.0 mm, the bottom width of the drainage groove is 0.4 mm to 2.0 mm, the height of the pointed fin is 0.8 mm to 4.0 mm, the pointed fin angle is 50° to 70°, and the rounded corner radius of the pointed fin is 0.05 mm to 0.30 mm.

[0022] Preferably, for a circular heat input wall, the number of periodic drainage grooves is 24 to 90, and at least some of the periodic drainage grooves are connected to a collection channel, which is an annular channel, a radial channel, a circumferential channel, or a combination thereof.

[0023] Furthermore, the dimensions of the heat sink are determined based on the heat input area of ​​the heat source, transient heat load, operating time, and allowable temperature rise, and the equivalent diameter of the heat input wall is used as a unified benchmark for scaling the dimensions of each component of the heat sink; the equivalent diameter is determined as follows:

[0024] For a circular heat input wall, its equivalent diameter is expressed as the actual diameter of the heat input wall; for a rectangular or non-circular heat input wall, its effective contact area is converted into an equivalent diameter according to the principle of area equivalence, expressed as: ,in The effective thermal contact area between the heat source and the heat sink. This is the equivalent diameter.

[0025] Preferably, the equivalent diameter of the heat input wall of a single heat sink module is 30mm to 180mm, and the total height of the sealed housing is 8mm to 70mm. When the geometry of the heat source exceeds the maximum coverage of a single heat sink module, multiple heat sink modules are connected in parallel or in an array to expand the coverage.

[0026] Preferably, the size of the thermal actuator array is proportionally matched to the equivalent diameter; the number of thermal actuators is 6 to 12; the length of each thermal actuator is 0.25 to 0.40 times the equivalent diameter of the heat input wall, the width is 0.06 to 0.10 times the equivalent diameter of the heat input wall, the thickness of the sealed flexible cavity is 0.4 mm to 3.0 mm, and the effective pressing stroke is 0.5 mm to 6.0 mm. The effective pressing stroke refers to the displacement distance that the force-applying end of the thermal actuator pushes toward the solid-liquid phase change material after being heated and deformed. This stroke range ensures that the thermal actuator can apply a compressive force toward the heat input wall to the solid phase change material after being heated and deformed, and compensates for the interfacial gap changes caused by the discharge of liquid phase change material during the melting process of the solid phase change material.

[0027] Preferably, the first sidewall of the sealed flexible cavity is a smooth sidewall, and the second sidewall is a pleated sidewall with periodic folds. The deformation of the pleated sidewall under the pressure inside the cavity is greater than the deformation of the smooth sidewall, causing the thermal actuator to bend in the direction of the smooth sidewall.

[0028] Preferably, the capillary transport structure includes a network of microchannels disposed on the inner wall of the sealed flexible cavity. The microchannel network has a main channel and branch channels communicating with the main channel to form a leaf vein-like capillary transport path.

[0029] Preferably, the lower part of the sealed flexible cavity forms a working fluid storage area, and the capillary transport structure is used to realize the circulation transport of the liquid gas-liquid phase change working fluid between the working fluid storage area and the evaporation area on the inner wall of the sealed flexible cavity.

[0030] Preferably, the sealing housing includes a base plate, a circumferential sidewall, and a removable sealing cover. The base plate forms the heat input wall surface, and the base plate is integrally formed or sealed to the circumferential sidewall. The removable sealing cover is sealed to the circumferential sidewall through a sealing element.

[0031] Preferably, the gas-liquid phase change working fluid is a low-boiling-point liquid compatible with the material of the sealed flexible cavity, and the boiling point of the low-boiling-point liquid is 20 ℃ to 60 ℃; the sealed flexible cavity is made of an elastomer material, an elastomer composite material, or a thin-walled material with flexible deformation capability.

[0032] The present invention also protects a thermal buffer system, comprising: a heat source, a terminal heat dissipation device, and the heat-driven high-efficiency phase change heat sink, wherein the heat-driven high-efficiency phase change heat sink is disposed between the heat source and the terminal heat dissipation device, for absorbing and temporarily storing heat when the heat source generates a transient heat load, and releasing the stored heat to the terminal heat dissipation device after the heat load of the heat source decreases.

[0033] Furthermore, the heat source is a high-power electronic device, a laser, a radar transmitting assembly, a pulsed power device, a battery system, or a transient high heat flux density component on a mobile platform.

[0034] This invention also protects a heat buffering method, implemented using the aforementioned heat buffering system, comprising the following steps:

[0035] The heat generated by the heat source is first transferred to the heat input wall; the heat input wall simultaneously transfers the heat to the solid-liquid phase change material and the thermal actuator array inside the sealed housing;

[0036] As heat is continuously input, the solid-liquid phase change material near the heat input wall undergoes contact melting, forming a molten liquid phase change material at the heat exchange interface; at the same time, each thermal actuator in the thermal actuator array receives heat transferred through the heat input wall, causing the gas-liquid phase change working fluid in the sealed flexible cavity to evaporate, and the internal pressure of the cavity gradually increases, thereby driving the thermal actuator to produce directional deformation.

[0037] The thermal actuator that generates directional deformation applies a continuous extrusion force toward the heat exchange interface to the solid-liquid phase change material through its force application end, so that the solid phase change material always maintains close contact with the heat input wall during the melting process.

[0038] Under the continuous pressure of the thermal actuator, a local thin liquid film is formed between the top of the pointed fin and the solid phase change material, and the molten liquid phase change material is driven by the extrusion pressure to migrate along the periodic drainage groove to the outer peripheral liquid collection channel, so as to reduce the thickness of the molten liquid film between the heat input wall and the solid phase change material and reduce the interfacial heat transfer thermal resistance.

[0039] When the heat load of the heat source decreases or stops, the temperature of the heat input wall drops, causing the gas-liquid phase change working fluid inside the thermal actuator to condense and the pressure inside the cavity to decrease, and the thermal actuator returns to its initial deformation state; the solid phase change material re-solidifies under external heat dissipation conditions, and the stored heat is released to the external environment through the terminal heat dissipation device, thus completing a complete thermal buffer cycle.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] First, the present invention uses a thermal actuator array as a self-driven pressure source, eliminating the need for external motors, cylinders, hydraulic or spring loading mechanisms. It can achieve self-driven contact melting solely by the heat source itself, effectively reducing system structural complexity, added mass and drive energy consumption. At the same time, the thermal actuator adopts an asymmetric flexible structure with smooth and pleated sidewalls, utilizing the difference in equivalent stiffness between the two sidewalls to generate bending in a predetermined direction, providing continuous contact force under different installation postures, significantly improving applicability in space-constrained and sealed environments.

[0042] Secondly, the present invention features a periodic pointed fin drainage structure at the heat input wall, which combines the functions of localized enhanced heat conduction, thin liquid film maintenance, and liquid phase change material drainage, effectively reducing the retention of molten material in the heat input area. Combined with the continuous pressure of the thermal actuator, the two work together to keep the solid phase change material in a highly efficient contact melting state with the heat input wall, reducing the interfacial heat transfer resistance and significantly improving the heat absorption power density of the phase change heat sink under short-term high heat flow input.

[0043] Third, this invention addresses typical transient high heat flux density scenarios such as high-power electronic devices, lasers, radar transmitting components, pulsed power equipment, and battery systems, providing specifications for heat sink modules, dimensions of thermal actuators, and ranges for drainage trench dimensions. This enables the thermally driven high-efficiency phase change heat sink to be modularly designed and flexibly expanded according to different heat source scales, exhibiting good engineering implementation adaptability and industrial application foundation. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of the thermally driven high-efficiency phase change heat sink of the present invention;

[0045] Figure 2 This is a schematic diagram of the thermal actuator in this invention;

[0046] Figure 3 This is a top view of the periodic drainage grooves on the inner side of the heat input wall in this invention.

[0047] Figure 4 This is a schematic cross-sectional view of the periodic pointed fins and drainage groove depth on the inner side of the heat input wall in this invention.

[0048] Figure 5 This is a schematic diagram showing the state of the thermal actuator bending and pressing the phase change material during the operation of the thermally driven high-efficiency phase change heat sink of the present invention.

[0049] The following are the labels in the diagram: 1. Sealed shell; 2. Solid-liquid phase change material; 3. Heat input wall; 4. Thermal actuator array; 41. Thermal actuator; 411. Sealed flexible cavity; 412. Liquid-gas-liquid phase change working fluid; 413. Capillary transport structure; 414. Force application end; 415. First sidewall; 416. Second sidewall; 417. Working fluid storage area; 5. Heat source; 61. Pointed fin; 62. Periodic drainage groove; 63. Outer peripheral liquid collection channel; 64. Central liquid collection area. Detailed Implementation

[0050] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] like Figures 1 to 5 As shown, the present invention provides a heat-driven high-efficiency phase change heat sink, comprising: a sealed shell 1, a solid-liquid phase change material 2, a heat input wall 3, a thermal actuator array 4, and a drain heat exchange structure;

[0052] The sealed housing 1 forms a closed space for accommodating the solid-liquid phase change material 2; the heat input wall 3 is located on the side of the sealed housing 1 near the heat source 5 for thermal coupling connection with the heat source 5, so that the heat generated by the heat source 5 can be transferred to the solid-liquid phase change material 2 and the thermal actuator array 4 through the heat input wall 3.

[0053] A thermal actuator array 4 is disposed inside the sealed housing 1 and thermally coupled to the heat input wall 3. The thermal actuator array 4 includes multiple thermal actuators 41, which are arranged at circumferential intervals along the sealed housing 1. Each thermal actuator 41 includes a sealed flexible cavity 411, a gas-liquid phase change working fluid 412, a capillary transport structure 413, and a force-applying end 414. The fixed end of the sealed flexible cavity 411 is connected to the heat input wall 3 or a heat-conducting structure connected to the heat input wall 3, so that the heat input... After receiving heat, the wall surface 3 can transfer some of the heat to the gas-liquid phase change working medium 412 inside the sealed flexible cavity 411, causing it to vaporize and increasing the pressure inside the sealed flexible cavity 411, thereby driving the sealed flexible cavity 411 to deform; the capillary transport structure 413 is disposed inside the sealed flexible cavity 411 to realize the circulation transport of the gas-liquid phase change working medium 412; the capillary transport structure 413 can be a microchannel network, a porous capillary core, a fiber capillary core, a sintered capillary core, or a combination thereof.

[0054] The drain heat exchange structure includes multiple pointed fins 61, which are radially distributed along the heat input wall 3. Periodic drain grooves 62 are formed between adjacent pointed fins 61. The pointed fins 61 adopt a triangular prism structure with a triangular cross-section and the top facing the solid-liquid phase change material 2. The top of the pointed fins 61 is used to form a local contact heat exchange area, and the inclined surfaces on both sides form a guide surface, so that the liquid phase change material generated by melting is introduced into the adjacent periodic drain grooves 62 and further migrates to the central liquid collection area 64 or the outer peripheral liquid collection channel 63 to receive and temporarily store the liquid phase change material discharged from the heat input area.

[0055] Specifically, the sealing housing 1 can be made of aluminum alloy, copper alloy, stainless steel or other metal materials with good thermal conductivity and structural strength; the sealing housing 1 includes a base plate, circumferential sidewalls and a sealing cover plate, wherein the base plate constitutes the heat input wall surface 3; the sealing cover can be connected to the circumferential sidewalls by bolts, welding, brazing, sealing ring tightening or other sealing connection methods to ensure that the solid-liquid phase change material 2 inside the sealing housing 1 does not leak during the melting and solidification cycle.

[0056] Specifically, the solid-liquid phase change material 2 is filled inside the sealed shell 1, and can be one or more of the following: paraffin-based phase change material, fatty acid-based phase change material, salt hydrate-based phase change material, low-melting-point metal, or composite phase change material.

[0057] Specifically, the sealed flexible cavity 411 is made of heat-resistant elastomer material, elastomer composite material, flexible metal thin-wall material or other materials with recoverable deformation capability; the gas-liquid phase change working medium 412 is selected from low-boiling-point liquids that are compatible with the material of the sealed flexible cavity 411, including fluorinated liquids, low-boiling-point organic working mediums or other working mediums that can undergo gas-liquid phase change within a predetermined temperature range.

[0058] In a preferred embodiment, the solid-liquid phase change material 2 is a paraffin-based phase change material that matches the operating temperature range of the heat source 5, with a phase change temperature range of 30 ℃ to 80 ℃; the solid-liquid phase change material 2 is at least partially solid in its initial state and is disposed adjacent to the heat input wall surface 3 and the drain heat exchange structure.

[0059] In a preferred embodiment, the number of thermal actuators 41 is 6 to 12, and they are evenly distributed circumferentially along the sealed housing 1, so that they can apply force to the solid-liquid phase change material 2 from multiple directions. By circumferentially arraying, the thermal actuators 41 can form a more uniform pressing action inside the heat sink, avoiding the solid phase change material from only being close to the heat input wall 3 in a local area.

[0060] In a preferred embodiment, the sealed flexible cavity 411 has a first sidewall 415 and a second sidewall 416 with different deformability; wherein, the first sidewall 415 is a smooth sidewall, and the second sidewall 416 is a pleated sidewall with periodic folds. The deformation of the pleated sidewall under the pressure inside the cavity is greater than that of the smooth sidewall. When the gas-liquid phase change working fluid 412 is heated and evaporates, causing the internal pressure of the sealed flexible cavity 411 to increase, the sealed flexible cavity 411 can bend in the direction of the smooth sidewall. This bending or deflection causes the force-applying end of the thermal actuator 41 to move toward the solid-liquid phase change material 2, and applies a compressive force toward the heat input wall 3 to the solid phase change material.

[0061] In a preferred embodiment, the boiling point of the gas-liquid phase change working medium 412 is 20 ℃ to 60 ℃, and it can be matched according to the working temperature of the heat source 5 and the phase change temperature of the solid-liquid phase change material 2, so that the thermal actuator 41 can generate a deformation response in a timely manner before and after the solid phase change material begins to melt.

[0062] In a preferred embodiment, the capillary transport structure 413 is a leaf vein-like microchannel network, including a main channel and multiple branch channels connected to the main channel; the lower part of the sealed flexible cavity 411 forms a working fluid storage area 417, and the capillary transport structure 413 uses capillary action to transport the liquid gas-liquid phase change working fluid 412 from the working fluid storage area 417 to the evaporation area near the liquid surface. The liquid gas-liquid phase change working fluid 412 is heated and vaporized in the evaporation area, so that the liquid gas-liquid phase change working fluid 412 in the sealed flexible cavity 411 is vaporized. The pressure in the chamber increases; the steam condenses into liquid after cooling in the upper part of the chamber. The liquid working fluid flows back to the working fluid storage area 417 under the action of gravity, pressure difference and capillary force, and is then transported back to the evaporation area by the capillary transport structure 413, forming a circulation transport of the working fluid between the storage area and the evaporation area. Through the capillary transport structure 413, the dependence of the thermal actuator 41 on a single direction of gravity can be reduced, and the liquid supply stability and actuation reliability of the thermal actuator 41 under different installation postures can be improved.

[0063] In a preferred embodiment, the pointed fins 61 can also be locally densified according to the shape of the heat source and the heat flow distribution to adapt to non-uniform heat flow scenarios.

[0064] Specifically, the structural parameters of the pointed fins 61 and the periodic drainage channels 62 are determined based on the thermal resistance of the molten liquid film and the flow resistance of the liquid phase change material; the thermal resistance of the molten liquid film can be expressed as... ,in For liquid film thickness, The thermal conductivity of the liquid phase change material is... This represents the effective heat exchange area. As shown in the formula, reducing the thickness of the molten liquid film can lower the interfacial thermal resistance. The top of the pointed fin 61 forms a localized contact with the solid phase change material under extrusion; the contact area is located near the tip of the pointed fin, and its contact width is much smaller than the width of the bottom of the pointed fin. This results in a thin liquid film contact area being formed at the contact interface.

[0065] The periodic drainage channels 62 formed between adjacent pointed fins 61 can be approximated as rectangular drainage channels to estimate the drainage pressure drop, i.e., the flow resistance of the liquid phase change material, which is expressed as: ,in The dynamic viscosity of liquid phase change materials. The length of the trench. This is the volumetric flow rate of the drained liquid. The width of the trench. Let be the trench depth. As can be seen from this formula, the trench depth has a significant impact on the drainage resistance. Appropriately increasing the trench depth is beneficial to reducing the drainage resistance of liquid phase change materials, but excessive trench depth will weaken the structural strength and thermal conductivity continuity of the heat input wall 3.

[0066] The cross-sectional geometry of the pointed fin 61 can be determined according to... Confirmed, among which The width of the bottom of the pointed fin. The height of the pointed fin. The included angle of the fins is 61; the periodic distance between adjacent fins 61 satisfies the following conditions. ,in For trenching cycle, This refers to the width of the bottom of the drainage channel.

[0067] In a preferred embodiment, in the application of paraffin-based phase change materials, the depth of the periodic drainage groove 62 is 0.8 mm to 4.0 mm, the periodic distance is 1.5 mm to 6.0 mm, the bottom width of the drainage groove is 0.4 mm to 2.0 mm, the height of the pointed fin is 0.8 mm to 4.0 mm, and the pointed angle is preferably 50° to 70°.

[0068] In another preferred embodiment, the inner wall of the periodic drainage groove 62 may be provided with a hydrophilic coating or hydrophilic microstructure to improve the ability of the liquid phase change material to migrate along the groove direction; the top of the pointed fin 61 or the non-drainage area may be provided with a relatively hydrophobic coating to reduce the retention of the liquid phase change material in the heat exchange contact area; through the cooperation of the hydrophilic drainage groove and the pointed fin structure, the ability of the liquid phase change material to be discharged from the heat input interface to the outer peripheral area can be further enhanced, thereby reducing the thickness of the molten liquid film between the heat input wall 3 and the solid phase change material 2.

[0069] By synergistically configuring a thermal actuator array and a periodic pointed-fin drainage structure, this invention integrates heat input, thermal actuation pressure, contact melting, and molten liquid drainage processes within a single sealed phase change heat sink. The thermal actuator array enables the solid phase change material to actively approach the heat input wall 3 during heating, while the periodic pointed-fin drainage structure allows the liquid phase change material to be discharged from the heat exchange interface in a timely manner. The combined effect of these two components effectively reduces the thickness of the molten liquid film near the heat input wall 3, lowers the interfacial thermal resistance, improves the heat absorption rate and thermal buffering capacity of the phase change heat sink under transient high heat flux density conditions, and enhances its applicability in miniaturized, hermetic, and multi-positional applications.

[0070] Example 1

[0071] This embodiment provides a thermal buffer system, including: a high-power electronic device or a small laser, a terminal heat dissipation device, and a heat-driven high-efficiency phase change heat sink disposed between the two; the heat-driven high-efficiency phase change heat sink adopts a circular module configuration; the high-power electronic device or small laser serves as a heat source, and the heat-driven high-efficiency phase change heat sink is used to absorb and temporarily store heat when the heat source generates a transient heat load, and release the stored heat to the terminal heat dissipation device after the heat load of the heat source decreases.

[0072] Specifically, the equivalent diameter of the heat input wall 3 of the heat-driven high-efficiency phase change heat sink is 60 mm, and the total height of the sealed shell 1 is 25 mm; the solid-liquid phase change material 2 is a paraffin-based phase change material with a phase change temperature of about 45°C; there are 6 thermal actuators 41, which are evenly arranged circumferentially; each thermal actuator 41 has a length of 18 mm, a width of 5 mm, a thickness of 1.0 mm for the sealed flexible cavity, and an effective pressing stroke of 2.0 mm.

[0073] The draining heat exchange structure includes multiple pointed fins 61, which are radially distributed along the heat input wall 3 and periodically arranged circumferentially. There are 36 periodic draining grooves 62; the groove depth is 2.0 mm, the groove period is 3.0 mm, and the bottom width is 0.8 mm. The height of the pointed fins 61 is 2.0 mm, the pointed angle is 60°, the rounded corner radius is 0.15 mm, and the bottom width is approximately 2.2 mm. The outer peripheral liquid collection channel 63 has a width of 3.0 mm and a depth of 2.0 mm. Through the matching design of the above dimensional parameters, a local thin liquid film can be formed in the pointed area, effectively reducing the interfacial thermal resistance; simultaneously, it provides a draining path for the molten paraffin to migrate from the central heat input area to the outer peripheral liquid collection channel.

[0074] Example 2

[0075] This embodiment provides a thermal buffer system, including: a radar transmitting component, a terminal heat dissipation device, and a heat-driven high-efficiency phase change heat sink disposed between the two; the heat-driven high-efficiency phase change heat sink is a medium-power heat sink module; the radar transmitting component serves as a heat source, and the heat-driven high-efficiency phase change heat sink is used to absorb and temporarily store heat when the heat source generates a transient heat load, and release the stored heat to the terminal heat dissipation device after the heat load of the heat source decreases.

[0076] Specifically, the equivalent diameter of the heat input wall 3 of the heat-driven high-efficiency phase change heat sink is 100 mm, and the total height of the sealed shell 1 is 40 mm; the solid-liquid phase change material 2 is a paraffin-based phase change material with a phase change temperature of about 55 ℃; there are 8 thermal actuators 41, which are evenly arranged circumferentially; each thermal actuator 41 has a length of 35 mm, a width of 8 mm, a thickness of 1.8 mm for the sealed flexible cavity, and an effective pressing stroke of 3.5 mm.

[0077] The drain heat exchange structure includes multiple pointed fins 61, which are radially distributed along the heat input wall 3 and periodically arranged circumferentially. There are 60 periodic drain grooves 62, each with a depth of 3.0 mm, a period of 4.6 mm, and a bottom width of 1.2 mm. The pointed fins 61 have a height of 3.0 mm, a pointed angle of 60°, a corner radius of 0.20 mm, and a bottom width of approximately 3.4 mm. The outer peripheral liquid collection channel 63 has a width of 4.0 mm and a depth of 3.0 mm. These heat sink dimensional parameters are suitable for medium-power radar transmitting units with an equivalent diameter of 100 mm, ensuring drain capacity while maintaining the thermal conductivity continuity of the heat input wall 3.

[0078] Example 3

[0079] This embodiment provides a thermal buffer system, including: a pulse power device or battery system, a terminal heat dissipation device, and a heat-driven high-efficiency phase change heat sink disposed between the two; the pulse power device or battery system serves as a heat source, and the heat-driven high-efficiency phase change heat sink is used to absorb and temporarily store heat when the heat source generates a transient heat load, and to release the stored heat to the terminal heat dissipation device after the heat load of the heat source decreases.

[0080] Specifically, the equivalent diameter of the heat input wall 3 of the heat-driven high-efficiency phase change heat sink is 150 mm, and the total height of the sealed shell 1 is 60 mm; the solid-liquid phase change material 2 is a paraffin-based phase change material with a phase change temperature of about 65°C; there are 12 thermal actuators 41, which are evenly arranged circumferentially; each thermal actuator 41 has a length of 50 mm, a width of 12 mm, a thickness of 2.5 mm for the sealed flexible cavity, and an effective pressing stroke of 5.0 mm.

[0081] The drain heat exchange structure includes multiple pointed fins 61, which are radially distributed along the heat input wall 3 or in a partitioned radial pattern, and arranged periodically in the circumferential direction. There are 72 periodic drain grooves 62, each with a depth of 4.0 mm, a period of 5.8 mm, and a bottom width of 1.6 mm. The pointed fins 61 have a height of 4.0 mm, a pointed angle of approximately 55°, a rounded corner radius of 0.25 mm, and a bottom width of approximately 4.2 mm. The outer peripheral liquid collection channel 63 has a width of 5.0 mm and a depth of 3.5 mm. For rectangular battery modules, the radial grooves can be replaced with parallel, partitioned radial, or gridded grooves, and multiple heat sink modules can be connected in parallel to cover the main heat-generating areas of the battery module.

[0082] In another embodiment, the force-applying end of the thermal actuator 41 can be configured as an arc-shaped pressure plate, a flexible pressure plate, a rolling contact end, or a wide-face contact end to increase the contact area between it and the solid phase change material and avoid local stress concentration; the force-applying end can also be connected to a heat-conducting sheet so that while pressing the solid phase change material, it can enhance the thermal conductivity of local areas inside the solid phase change material.

[0083] In another embodiment, the multiple thermal actuators 41 can be divided into several groups, with each group of thermal actuators corresponding to a high heat flux region on the heat input wall 3. For application scenarios where the heat source distribution is uneven, the number of thermal actuators 41 or their arrangement density can be increased near the high heat flux density region, so that the local high temperature region can obtain stronger pressing pressure and faster liquid drainage capacity.

[0084] In another embodiment, the groove depth, groove width, and groove spacing of the periodic drainage groove 62 can be designed according to the viscosity, melting temperature, heat input power, and heat sink size of the solid-liquid phase change material 2; the periodic drainage groove 62 can provide a low-resistance drainage path for the liquid phase change material 22 without significantly weakening the structural strength and thermal conductivity of the heat input wall 3; the pointed fins 61 can be formed by machining, precision milling, laser processing, etching, die casting, sintering, or additive manufacturing.

[0085] Example 4

[0086] This embodiment also provides a heat buffering method, implemented using the aforementioned heat buffering system, comprising the following steps:

[0087] When the heat source 5 starts working and generates a transient thermal load, the heat is first transferred to the heat input wall 3; the heat input wall 3 simultaneously transfers the heat to the solid-liquid phase change material 2 and the thermal actuator array 4 inside the sealed housing 1.

[0088] As heat is continuously input, the solid phase change material 21 near the heat input wall 3 melts, causing the gas-liquid phase change working medium 412 inside the thermal actuator 41 to evaporate. As the gas-liquid phase change working medium 412 evaporates, the pressure inside the sealed flexible cavity 411 increases, and the sealed flexible cavity 411 undergoes directional bending or deflection due to the different deformation capabilities of the two side walls.

[0089] After the thermal actuator 41 bends, its force-applying end 414 moves toward the solid-liquid phase change material 2 and applies a compressive force toward the heat input wall 3 to the solid phase change material. Under the action of this compressive force, the solid phase change material continues to approach the heat input wall 3 and its pointed fins 61, so that the solid phase change material and the heat input wall 3 maintain a small gap or local contact state. As a result, a stable contact melting process is formed near the heat input wall 3, and heat can be transferred to the solid-liquid phase change interface through a thin molten liquid film, thereby improving the melting rate of the phase change material and the transient heat absorption capacity of the heat sink.

[0090] During the contact melting process, the liquid phase change material generated near the heat input wall 3 is guided into the periodic drainage groove 62 between adjacent pointed fins 61 under the combined action of the extrusion force applied by the thermal actuator 41, the solid-liquid interface pressure, and the flow guide surface of the pointed fin 61. Subsequently, the liquid phase change material migrates along the periodic drainage groove 62 to the outer peripheral liquid collection channel 63 or other low-resistance flow areas. Since the liquid phase change material can be discharged from the heat exchange interface in time, the liquid film between the heat input wall 3 and the solid phase change material is not easy to continuously thicken, thereby reducing the interfacial thermal resistance and avoiding the decrease in heat absorption rate due to the retention of liquid phase change material.

[0091] When the heat load of heat source 5 decreases or stops, the temperature of heat input wall 3 drops, the gas-liquid phase change working medium 412 inside thermal actuator 41 gradually condenses, and the pressure inside the sealed flexible cavity 411 decreases. As the pressure inside the cavity decreases, thermal actuator 41 gradually resets under the elastic restoring force of the flexible cavity itself, and the squeezing force of the force-applying end 414 on solid-liquid phase change material 2 decreases. At the same time, solid-liquid phase change material 2 re-solidifies under external heat dissipation conditions, and the stored heat is released to the external environment through the terminal heat dissipation device, thus completing a complete thermal buffer cycle.

[0092] It should be understood that the above-described embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or conventional modifications made by those skilled in the art to various structural forms, material types, dimensional parameters, and arrangement methods without departing from the technical concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A heat-driven high-efficiency phase change heat sink, characterized in that, include: Sealed housing; A solid-liquid phase change material is disposed within the sealed housing; Heat input wall surface, used to receive heat from the component to be cooled; A thermal actuator array is disposed within the sealed housing and thermally coupled to the heat input wall surface, and the thermal actuator array is arranged at circumferential intervals along the sealed housing. And a drain heat exchange structure, which is disposed on the side of the heat input wall facing the solid-liquid phase change material; Each thermal actuator in the thermal actuator array includes a sealed flexible cavity that is thermally connected or thermally coupled to the heat input wall and a force-applying end facing the solid-liquid phase change material. The sealed flexible cavity is configured to generate directional deformation when heated, so as to apply a compressive force towards the heat exchange interface to the solid-liquid phase change material through the force-applying end, causing the molten phase change material at the heat exchange interface to migrate towards the draining heat exchange structure. The draining heat exchange structure is located within the enclosed area of ​​the thermal actuator array and is used to migrate and guide the molten phase change material at the heat exchange interface away from the heat exchange interface.

2. The heat-driven high-efficiency phase change heat sink according to claim 1, characterized in that, The thermal actuator also includes a gas-liquid phase change working fluid housed within the sealed flexible cavity, and a capillary transport structure disposed on the inner wall of the sealed flexible cavity; when the heat input wall receives heat, the gas-liquid phase change working fluid is heated and evaporates, causing the sealed flexible cavity to undergo directional deformation; the capillary transport structure is used to realize the cyclic transport of the gas-liquid phase change working fluid.

3. The heat-driven high-efficiency phase change heat sink according to claim 1, characterized in that, The sealed flexible cavity has a first sidewall and a second sidewall with different deformation capabilities.

4. The heat-driven high-efficiency phase change heat sink according to claim 1, characterized in that, The draining heat exchange structure includes multiple pointed fins, and periodic draining channels are formed between adjacent pointed fins for transporting molten phase change material; the molten phase change material at the heat exchange interface migrates along the periodic draining channels.

5. The heat-driven high-efficiency phase change heat sink according to claim 4, characterized in that, For a circular heat input wall, the pointed fins are radially distributed along the radial direction of the heat input wall and / or periodically distributed along the circumference of the heat input wall; the periodic drainage grooves extend from the central region of the heat input wall to the outer peripheral region.

6. The heat-driven high-efficiency phase change heat sink according to claim 4 or 5, characterized in that, The cross-section of the pointed fin is triangular, trapezoidal, arc-shaped pointed structure or a combination thereof. The top of the pointed fin is positioned facing the solid-liquid phase change material, and under the extrusion of the thermal actuator, it forms a local contact or near-contact heat exchange area with the solid phase change material. The two side walls of the pointed fin serve as flow guiding surfaces to guide the liquid phase change material into adjacent periodic drainage channels.

7. The heat-driven high-efficiency phase change heat sink according to claim 4 or 5, characterized in that, The inner wall of the periodic drainage channel is provided with a hydrophilic coating or hydrophilic microstructure; the top of the pointed fin or the non-drainage area is provided with a hydrophobic coating.

8. The heat-driven high-efficiency phase change heat sink according to claim 1, characterized in that, The solid-liquid phase change material is at least one of paraffin-based phase change materials, fatty acid-based phase change materials, salt hydrate-based phase change materials, low-melting-point metal or alloy-based phase change materials, and composite phase change materials; wherein the phase change temperature of the paraffin-based phase change material is 30°C to 80°C.

9. The heat-driven high-efficiency phase change heat sink according to claim 4 or 5, characterized in that, When the solid-liquid phase change material is a paraffin-based phase change material, the depth of the periodic drainage groove is 0.8 mm to 4.0 mm, the periodic distance between adjacent pointed fins is 1.5 mm to 6.0 mm, the bottom width of the drainage groove is 0.4 mm to 2.0 mm, the height of the pointed fin is 0.8 mm to 4.0 mm, the pointed fin angle is 50° to 70°, and the rounded corner radius of the pointed fin is 0.05 mm to 0.30 mm.

10. The heat-driven high-efficiency phase change heat sink according to claim 5, characterized in that, The number of periodic drainage channels is 24 to 90, and at least some of the periodic drainage channels are connected to the collection channel, which is an annular channel, a radial channel, a circumferential channel, or a combination thereof.

11. The heat-driven high-efficiency phase change heat sink according to any one of claims 1 to 5, characterized in that, The dimensions of the heat sink are determined based on the heat input area of ​​the heat source, transient heat load, operating time, and allowable temperature rise, with the equivalent diameter of the heat input wall serving as a unified benchmark for scaling the dimensions of all components of the heat sink; the equivalent diameter is determined as follows: For a circular heat input wall, its equivalent diameter is expressed as the actual diameter of the heat input wall; for a rectangular or non-circular heat input wall, its effective contact area is converted into an equivalent diameter according to the principle of area equivalence, expressed as: ,in The effective thermal contact area between the heat source and the heat sink. This is the equivalent diameter.

12. The heat-driven high-efficiency phase change heat sink according to claim 11, characterized in that, The equivalent diameter of the heat input wall of a single heat sink module is 30mm to 180mm, and the total height of the sealed housing is 8mm to 70mm. When the geometry of the heat source exceeds the maximum coverage of a single heat sink module, multiple heat sink modules are connected in parallel or in an array to expand the coverage.

13. The heat-driven high-efficiency phase change heat sink according to claim 11, characterized in that, The number of thermal actuators is 6 to 12; the length of each thermal actuator is 0.25 to 0.40 times the equivalent diameter of the heat input wall, the width is 0.06 to 0.10 times the equivalent diameter of the heat input wall, the thickness of the sealed flexible cavity is 0.4 mm to 3.0 mm, and the effective pressing stroke is 0.5 mm to 6.0 mm.

14. The heat-driven high-efficiency phase change heat sink according to claim 3, characterized in that, The first sidewall of the sealed flexible cavity is a smooth sidewall, and the second sidewall is a pleated sidewall with periodic folds. The deformation of the pleated sidewall under the pressure inside the cavity is greater than that of the smooth sidewall, causing the thermal actuator to bend in the direction of the smooth sidewall.

15. The heat-driven high-efficiency phase change heat sink according to claim 2, characterized in that, The capillary transport structure includes a network of microchannels disposed on the inner wall of the sealed flexible cavity. The microchannel network has a main channel and branch channels connected to the main channel to form a leaf vein-like capillary transport path.

16. The heat-driven high-efficiency phase change heat sink according to claim 15, characterized in that, The lower part of the sealed flexible cavity forms a working fluid storage area, and the capillary transport structure is used to realize the circulation transport of the liquid gas-liquid phase change working fluid between the working fluid storage area and the evaporation area on the inner wall of the sealed flexible cavity.

17. The heat-driven high-efficiency phase change heat sink according to any one of claims 1 to 5, 8, 10, and 14 to 16, characterized in that, The sealed housing includes a base plate, a circumferential side wall, and a removable sealing cover. The base plate forms the heat input wall surface. The base plate is integrally formed or sealed to the circumferential side wall. The removable sealing cover is sealed to the circumferential side wall through a sealing element.

18. The heat-driven high-efficiency phase change heat sink according to any one of claims 2, 15 to 16, characterized in that, The gas-liquid phase change working medium is a low-boiling-point liquid compatible with the material of the sealed flexible cavity, and the boiling point of the low-boiling-point liquid is 20 ℃ to 60 ℃; the sealed flexible cavity is made of an elastomer material, an elastomer composite material, or a thin-walled material with flexible deformation capability.

19. A thermal buffer system, characterized in that, include: The invention includes a heat source, a terminal heat dissipation device, and a heat-driven high-efficiency phase change heat sink as described in any one of claims 1 to 5, 8, 10, 14 to 16. The heat-driven high-efficiency phase change heat sink is disposed between the heat source and the terminal heat dissipation device, and is used to absorb and temporarily store heat when the heat source generates a transient heat load, and to release the stored heat to the terminal heat dissipation device after the heat load of the heat source decreases.

20. The heat buffer system according to claim 18, characterized in that, The heat source is a high-power electronic device, laser, radar transmitting assembly, pulsed power device, battery system, or transient high heat flux density component on a mobile platform.

21. A heat buffering method, characterized in that, Implemented using the heat buffer system of claim 18, comprising the following steps: The heat generated by the heat source is first transferred to the heat input wall; the heat input wall simultaneously transfers the heat to the solid-liquid phase change material and the thermal actuator array inside the sealed housing; As heat is continuously input, the solid-liquid phase change material near the heat input wall undergoes contact melting, forming a molten liquid phase change material at the heat exchange interface; at the same time, each thermal actuator in the thermal actuator array receives heat transferred through the heat input wall, causing the gas-liquid phase change working fluid in the sealed flexible cavity to evaporate, and the internal pressure of the cavity gradually increases, thereby driving the thermal actuator to produce directional deformation. The thermal actuator that generates directional deformation applies a continuous extrusion force toward the heat exchange interface to the solid-liquid phase change material through its force application end, so that the solid phase change material always maintains close contact with the heat input wall during the melting process. Under the continuous pressure of the thermal actuator, a local thin liquid film is formed between the top of the pointed fin and the solid phase change material, and the molten liquid phase change material is driven by the extrusion pressure to migrate along the periodic drainage groove to the outer peripheral liquid collection channel, so as to reduce the thickness of the molten liquid film between the heat input wall and the solid phase change material and reduce the interfacial heat transfer thermal resistance. When the heat load of the heat source decreases or stops, the temperature of the heat input wall drops, causing the gas-liquid phase change working fluid inside the thermal actuator to condense and the pressure inside the cavity to decrease, and the thermal actuator returns to its initial deformation state; the solid phase change material re-solidifies under external heat dissipation conditions, and the stored heat is released to the external environment through the terminal heat dissipation device to complete a complete thermal buffer cycle.

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