Plate-type pulsating heat pipe coupled with phase change material and liquid cooling system

Abstract

A plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system relates to a pulsating heat pipe and comprises a plate-type pulsating heat pipe body and a cooling box. The plate-type pulsating heat pipe body comprises a heat conduction cover plate and a heat conduction substrate, the heat conduction substrate is divided into an evaporation area, a heat insulation area and a condensation area from bottom to top, the heat conduction substrate is vertically provided with multiple turns of channels for realizing mutual communication of the three areas, and the bottom end of the heat conduction substrate is provided with a liquid filling port; the heat-conducting cover plate is fixed on the heat-conducting substrate in a sealing manner; a phase change material and a liquid cooling system are installed in the cooling box, and the cooling box is connected with the condensation area of the plate-type pulsating heat pipe body in a sealed mode through the connecting opening. Rectangular groove walls and sine curve-shaped groove walls are alternately distributed in the heat conduction substrate to form the bent groove channels which are connected end to end. The system is high in heat transfer rate, excellent in heat dissipation performance and high in adaptability to high-power thermal shock, has the advantages of being low in cost, quick in response, high in reliability, good in compatibility, capable of being intelligently integrated and the like, and is easy to apply and popularize.

Description

Technical Field

[0001] The invention relates to a pulsating heat pipe, in particular to a plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system. Background Art

[0002] With the rapid development of automobile technology, car headlights are no longer just lighting tools. They have made significant progress in performance and intelligence. However, with the increase in the brightness of car headlights and the increasing diversification of functions, the problem of heat dissipation has become increasingly prominent. Traditional car headlight heat dissipation methods such as natural air cooling or simple aluminum radiators are difficult to meet the heat dissipation requirements when dealing with the high-power and high-heat flux density working conditions of modern car headlights. The continuous accumulation of heat causes the light decay of the headlights to accelerate, the service life is greatly shortened, and may even cause circuit failures, which has a negative impact on driving safety. In this case, pulsating heat pipes have attracted much attention as a two-phase heat transfer technology with great development potential. It relies on the synergistic effect of temperature difference, pressure difference and surface tension of the internal working fluid to achieve gas-liquid pulsating flow, thereby achieving the effect of efficient heat transfer.

[0003] However, traditional tubular pulsating heat pipes have many defects, such as small contact area, large volume, complex structure, difficult processing and high cost. In contrast, plate-type pulsating heat pipes have significant advantages. They have a wide heat transfer contact area, light structure, easy processing, flexible heat conduction paths, and can better adapt to complex spatial layouts and heat dissipation requirements. However, it should be noted that a single plate-type pulsating heat pipe is not perfect. There are still problems such as limited heat transfer rate and the need to enhance the adaptability to high-power thermal shock. Summary of the invention

[0004] The technical problem to be solved by the present invention is: the present invention proposes a plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system to solve the shortcomings of existing plate-type pulsating heat pipes, namely, limited heat transfer rate and need to enhance adaptability to high-power thermal shock.

[0005] The technical solution to the technical problem solved by the present invention is: a plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system, comprising a plate-type pulsating heat pipe body and a cooling box; the plate-type pulsating heat pipe body comprises a heat-conducting cover plate and a heat-conducting substrate, the heat-conducting substrate is divided into an evaporation zone, an insulation zone, and a condensation zone from bottom to top, the heat-conducting substrate is vertically provided with a multi-turn groove for interconnecting the three zones, and a liquid filling port is provided at the bottom end of the heat-conducting substrate; the heat-conducting cover plate is sealed and fixed on the heat-conducting substrate; the phase change material and the liquid cooling system are installed in the cooling box, and the cooling box is sealed and connected to the condensation zone of the plate-type pulsating heat pipe body through a connecting port.

[0006] A further technical solution of the present invention is that rectangular groove walls and sinusoidal groove walls are alternately distributed in the heat-conducting substrate to form the curved grooves that are connected end to end.

[0007] A further technical solution of the present invention is that a rectangular groove is provided in the condensation area of ​​the plate-type pulsating heat pipe body.

[0008] A further technical solution of the present invention is: the liquid cooling system comprises an S-shaped cooling pipe and a cooling medium located in the cooling pipe.

[0009] A further technical solution of the present invention is that the phase change material in the cooling box is an expanded graphite-wax composite phase change material.

[0010] A further technical solution of the present invention is that the working fluid flowing in the groove of the plate-type pulsating heat pipe body is a self-wetting fluid or a nanofluid or a nano self-wetting fluid.

[0011] A further technical solution of the present invention is: the self-wetting fluid includes a mixture of n-butanol and water, and a mixture of n-pentanol and water; the nanofluid includes a nano-ferroferric oxide water mixture, and a carbon nanotube water mixture; the nano self-wetting fluid includes a nano-ferroferric oxide n-butanol and water mixture, a nano-ferroferric oxide n-pentanol and water mixture, a carbon nanotube n-butanol and water mixture, and a carbon nanotube n-pentanol and water mixture.

[0012] A further technical solution of the present invention is that when the working fluid flowing in the groove of the plate-type pulsating heat pipe body is a nano-ferroferric oxide water mixture or a nano-ferroferric oxide n-butanol water mixture, an external magnetic field is also applied around the plate-type pulsating heat pipe body.

[0013] A further technical solution of the present invention is: the flow rate of the cooling medium in the cooling pipe is automatically controlled by an external intelligent control system; the intelligent control system includes a pump, a valve, a controller and a temperature measuring element in the evaporation area of ​​the heat-conducting substrate, the signal output end of the temperature measuring element in the evaporation area of ​​the heat-conducting substrate is connected to the signal input end of the controller, and the signal output end of the controller is respectively connected to the input end of the pump and the valve.

[0014] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. High heat transfer rate The present invention includes a plate-type pulsating heat pipe body and a cooling box. The plate-type pulsating heat pipe body includes a heat-conducting cover plate and a heat-conducting substrate. The heat-conducting substrate is divided into an evaporation zone, an insulation zone, and a condensation zone from bottom to top. After the evaporation zone of the heat-conducting substrate absorbs heat from an external heat source, it transfers the heat to the condensation zone of the heat-conducting substrate through the heat transfer of the gas-liquid two-phase pulsating flow in the multi-turn groove. Since the condensation zone of the heat-conducting substrate is equipped with a cooling box coupling phase change material and a liquid cooling system, the heat of the condensation zone of the heat-conducting substrate is absorbed by the phase change material in the cooling box and the cooling medium in the liquid cooling system, and the bubbles in the grooves are cooled, contracted, and burst, releasing the heat therein and converting it into liquid, which flows back to the evaporation zone of the heat-conducting substrate along with the gas-liquid two-phase pulsating flow, thereby completing the flow cycle of the heat pipe working medium. Therefore, the present invention has a high heat transfer rate.

[0015] In addition, rectangular groove walls and sinusoidal groove walls are alternately distributed in the heat-conducting substrate of the present invention, forming a curved groove connected end to end. This groove structure increases the disturbance degree and pulsating pressure difference of the fluid, while thinning the boundary layer, further increasing the nucleation site and heat transfer contact area, significantly improving the heat transfer rate and anti-burning ability.

[0016] In addition, the condensation area of ​​the plate-type pulsating heat pipe body of the present invention, that is, the front side of the heat-conducting cover plate and the back side of the heat-conducting substrate are provided with rectangular grooves, which further expands the heat dissipation area of ​​the plate-type pulsating heat pipe body and the cooling system and enhances the heat dissipation rate.

[0017] Furthermore, the phase change material in the cooling box of the present invention is an expanded graphite-wax composite phase change material. The expanded graphite greatly improves the thermal conductivity of the phase change material, and improves the heat absorption and heat dissipation capabilities of the phase change material.

[0018] 2. Excellent heat dissipation performance and strong adaptability to high-power thermal shock The present invention adopts a plate-type pulsating heat pipe design, which greatly increases the heat dissipation area. Sinusoidal and rectangular groove walls are alternately arranged in the heat-conducting substrate, which increases the disturbance degree and pulsating pressure difference of the fluid, further increases the nucleation site and heat transfer contact area, and a rectangular groove is arranged in the condensation area of ​​the heat-conducting cover plate to further expand the heat dissipation area. In addition, the organic combination of composite phase change material and liquid cooling channel greatly improves the adaptability to high-power thermal shock and accelerates the heat dissipation speed, which is particularly suitable for heat dissipation of high-density heat flow electronic devices.

[0019] 3. Low cost The present invention adopts a plate-type pulsating heat pipe design, which is simpler in structure, easier to process, and has a flexible heat conduction path compared to a tube-type pulsating heat pipe. It is easy to install and maintain, and is easy to integrate with other heat dissipation systems or energy storage components, which can significantly reduce related operating costs.

[0020] 4. Quick response The cooling box coupled with the phase change material and the liquid cooling system of the present invention can respond quickly when the heating power of the equipment suddenly increases, increase the flow rate of the cooling medium of the liquid cooling system in the cooling box, and further improve the heat dissipation efficiency to ensure the normal operation of the equipment.

[0021] 5. Strong reliability The present invention combines multiple heat dissipation technologies, adopts a new heat pipe working fluid and a new heat pipe structure, and combines the high heat absorption capacity of phase change materials. It can maintain stable performance under extreme high-power thermal shock conditions, reducing the probability of equipment damage due to its heat dissipation failure.

[0022] 6. Good compatibility The present invention belongs to a plate-type pulsating heat pipe, which has a compact structure and a flat surface, and can be seamlessly connected with a variety of different types of electronic components and heat dissipation devices, thereby improving the overall heat dissipation efficiency without the need for complicated adaptation work.

[0023] 7. Intelligent integration The present invention can be combined with an intelligent control system to automatically adjust the flow rate of the cooling medium in the cooling pipe of the liquid cooling system according to the operating state of the heat load, thereby further improving the heat transfer efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the appearance structure of the composite plate type pulsating heat pipe of the present invention; Figure 2 This is a schematic diagram of the internal structure of the composite plate type pulsating heat pipe of the present invention after removing the cooling box cover plate and the heat conduction cover plate; Figure 3 It is a schematic diagram of the front structure of the thermal conductive substrate; Figure 4 is a schematic diagram of the back structure of the thermal conductive substrate; Figure 5 It is a schematic diagram of the front structure of the heat-conducting cover plate; Figure 6 Schematic diagram of the internal structure of the cooling box after removing its cover.

[0025] In the accompanying drawings, the descriptions of the reference numerals are as follows: 1-cooling box; 11-water outlet; 12-water inlet; 13-cooling pipe; 14-connection port; 2-heat-conducting cover plate; 21-rectangular groove Ⅰ; 3-heat-conducting substrate; 31-rectangular groove wall; 32-sinusoidal groove wall; 33-liquid filling port, 34-rectangular groove II; A-evaporation zone, B-adiabatic zone, C-condensation zone. DETAILED DESCRIPTION Embodiment 1

[0026] Reference Figures 1 to 6 A plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system, comprising a plate-type pulsating heat pipe body and a cooling box 1; the plate-type pulsating heat pipe body comprises a heat-conducting cover plate 2 and a heat-conducting substrate 3, the heat-conducting substrate 3 being divided into an evaporation zone A, an insulation zone B, and a condensation zone C from bottom to top, the heat-conducting substrate 3 being vertically provided with a multi-turn groove to realize the interconnection of the three zones, and a liquid filling port 33 being provided at the bottom of the heat-conducting substrate; the heat-conducting cover plate 2 is placed on the heat-conducting substrate 3 and sealed by welding. Phase change material and a liquid cooling system are installed in the cooling box 1, and the cooling box 1 is sealed by welding with the condensation zone C of the plate-type pulsating heat pipe body through a connecting port 14. After the evaporation zone of the heat-conducting substrate 3 absorbs heat from an external heat source, it transfers heat to the condensation zone of the heat-conducting substrate through the heat transfer of the gas-liquid two-phase pulsating flow in the multi-turn groove. Since the cooling box 1 coupling phase change material and liquid cooling system is installed in the condensation area of ​​the heat-conducting substrate, the heat of the condensation area of ​​the heat-conducting substrate is absorbed by the phase change material in the cooling box and the cooling medium in the cooling pipe 13, and the bubbles in the groove are cooled, contracted and broken, releasing the heat therein and converting into liquid, and returning to the evaporation area of ​​the heat-conducting substrate accompanied by gas-liquid two-phase pulsating flow, thereby completing the flow cycle of the heat pipe working medium. The phase change material is responsible for the storage and absorption of heat energy in the condensation area of ​​the heat-conducting substrate 3, plays a heat buffering role, provides more sufficient reaction time for the liquid cooling system, and finally takes away the heat through the cooling medium in the liquid cooling system to achieve continuous operation of the device. There are two S-shaped cooling pipes 13 in the cooling box 1. Cooling water enters the cooling pipe 13 through the water inlet 12 of the cooling box 1, and after absorbing the heat stored in the phase change material, it goes out from the water outlet 11 of the cooling box 1.

[0027] Rectangular groove walls 31 and sinusoidal groove walls 32 are alternately distributed in the thermal conductive substrate 3 to form a curved groove that is connected end to end. This groove structure increases the disturbance degree and pulsating pressure difference of the fluid, while thinning the boundary layer, further increasing the nucleation site and heat transfer contact area, and significantly improving the heat transfer rate and anti-burning ability.

[0028] The condensation area of ​​the plate-type pulsating heat pipe body, i.e., the front side of the heat-conducting cover plate 2 and the back side of the heat-conducting substrate 3, is provided with rectangular grooves, wherein a rectangular groove I21 is provided on the front side of the heat-conducting cover plate 2, and a rectangular groove II34 is provided on the back side of the heat-conducting substrate 3, further expanding the heat dissipation area of ​​the plate-type pulsating heat pipe body and the cooling system, and enhancing the heat dissipation rate.

[0029] The phase change material in the cooling box 1 is an expanded graphite-paraffin composite phase change material. The expanded graphite greatly improves the thermal conductivity of the phase change material, and improves the heat absorption and heat dissipation capabilities of the phase change material.

[0030] The cooling medium flow rate in the cooling tube 13 in the cooling box 1 is adjustable, and automatic control is achieved through an external intelligent control system; the intelligent control system includes a pump, a valve, a controller and a temperature measuring element of the evaporation zone of the heat-conducting substrate, and the signal output end of the temperature measuring element of the evaporation zone of the heat-conducting substrate is connected to the signal input end of the controller, and the signal output end of the controller is respectively connected to the input end of the pump and the valve. The cooling medium can react quickly according to the evaporation zone of the heat-conducting substrate. When the heat load is large, the flow rate is increased to cooperate with the phase change material to quickly absorb and transfer heat; when the heat load is small, the flow rate is appropriately reduced to ensure appropriate heat dissipation efficiency and reduce system power consumption, thereby ensuring stable operation of the equipment.

[0031] The working fluid flowing in the groove of the pulsating heat pipe body can be a self-wetting fluid or a nanofluid or a nano self-wetting fluid, and the self-wetting fluid includes a n-butanol water mixture and a n-pentanol water mixture; the nanofluid includes a nano-ferroferric oxide water mixture and a carbon nanotube water mixture; the nano self-wetting fluid includes a nano-ferroferric oxide n-butanol water mixture, a nano-ferroferric oxide n-pentanol water mixture, a carbon nanotube n-butanol water mixture, and a carbon nanotube n-pentanol water mixture. When the working fluid is a nano-ferroferric oxide water mixture or a nano-ferroferric oxide n-butanol water mixture, an external magnetic field is applied around the plate-type pulsating heat pipe, such as installing an electromagnet or a permanent magnet on the outside of the pulsating heat pipe body, and the degree of disturbance, self-wetting ability and nucleation sites are increased by improving the thermal conductivity of the working fluid, the Margonni effect and the regulation of the magnetic field, thereby further improving the heat transfer performance of the plate-type pulsating heat pipe.

Claims

1. A plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system, characterized in that: It includes a plate-type pulsating heat pipe body and a cooling box; the plate-type pulsating heat pipe body includes a heat-conducting cover plate and a heat-conducting substrate, the heat-conducting substrate is divided into an evaporation zone, an insulation zone, and a condensation zone from bottom to top, the heat-conducting substrate is vertically provided with a multi-turn groove to realize the interconnection of the three zones, and a liquid filling port is provided at the bottom end of the heat-conducting substrate; the heat-conducting cover plate is sealed and fixed on the heat-conducting substrate; the cooling box is installed with a phase change material and a liquid cooling system, and is sealed and connected to the condensation zone of the plate-type pulsating heat pipe body through a connecting port.

2. A plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 1, characterized in that: Rectangular groove walls and sinusoidal groove walls are alternately distributed in the heat-conducting substrate to form the curved groove that is connected end to end.

3. The plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 1, characterized in that: The condensation area of ​​the plate-type pulsating heat pipe body is provided with a rectangular groove.

4. The plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 1, characterized in that: The liquid cooling system comprises an S-shaped cooling pipe and a cooling medium located in the cooling pipe.

5. The plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 1, characterized in that: The phase change material in the cooling box is an expanded graphite paraffin composite phase change material.

6. The plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 1, characterized in that: The working medium flowing in the groove of the plate-type pulsating heat pipe body is a self-wetting fluid or a nanofluid or a nano self-wetting fluid.

7. A plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 6, characterized in that: The self-wetting fluid includes a mixture of n-butanol and water, and a mixture of n-pentanol and water; the nanofluid includes a nano-ferroferric oxide water mixture, and a carbon nanotube water mixture; the nano self-wetting fluid includes a nano-ferroferric oxide n-butanol and water mixture, a nano-ferroferric oxide n-pentanol and water mixture, a carbon nanotube n-butanol and water mixture, and a carbon nanotube n-pentanol and water mixture.

8. The plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 6, characterized in that: When the working medium flowing in the groove of the plate-type pulsating heat pipe body is a nano-ferroferric oxide water mixture or a nano-ferroferric oxide n-butanol water mixture, an external magnetic field is also applied around the plate-type pulsating heat pipe body.

9. The plate-type pulsating heat pipe coupled with a phase change material and a liquid cooling system according to claim 4, characterized in that: The flow rate of the cooling medium in the cooling pipe is automatically controlled by an external intelligent control system; the intelligent control system includes a pump, a valve, a controller and a temperature measuring element in the evaporation zone of the heat-conducting substrate, the signal output end of the temperature measuring element in the evaporation zone of the heat-conducting substrate is connected to the signal input end of the controller, and the signal output end of the controller is respectively connected to the input end of the pump and the valve.

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