CN115307469A - Multi-source driven high-power loop heat pipe heat dissipation device - Google Patents
Multi-source driven high-power loop heat pipe heat dissipation device Download PDFInfo
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- CN115307469A CN115307469A CN202210949782.8A CN202210949782A CN115307469A CN 115307469 A CN115307469 A CN 115307469A CN 202210949782 A CN202210949782 A CN 202210949782A CN 115307469 A CN115307469 A CN 115307469A
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- 230000017525 heat dissipation Effects 0.000 title claims abstract description 37
- 239000007788 liquid Substances 0.000 claims description 60
- 239000002184 metal Substances 0.000 claims description 19
- 229910052751 metal Inorganic materials 0.000 claims description 19
- 239000000843 powder Substances 0.000 claims description 19
- 238000002156 mixing Methods 0.000 claims description 17
- 230000007246 mechanism Effects 0.000 claims description 11
- 239000011148 porous material Substances 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000003825 pressing Methods 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 238000005245 sintering Methods 0.000 claims description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 4
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- 229910021641 deionized water Inorganic materials 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 3
- 238000003892 spreading Methods 0.000 claims description 3
- 230000007480 spreading Effects 0.000 claims description 3
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 3
- 238000009835 boiling Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical group [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
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- 239000012071 phase Substances 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
- F28D15/043—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure forming loops, e.g. capillary pumped loops
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/06—Control arrangements therefor
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
- H05K7/20336—Heat pipes, e.g. wicks or capillary pumps
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
- H05K7/20381—Thermal management, e.g. evaporation control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D2015/0291—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes comprising internal rotor means, e.g. turbine driven by the working fluid
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
The invention discloses a multi-source driven high-power loop heat pipe heat dissipation device which is used for dissipating heat of a chip and comprises an evaporator, a condenser and a control assembly, wherein the evaporator is used for absorbing heat dissipated by the chip and comprises a shell and a capillary core, the capillary core can be filled with a working medium, the shell is provided with a sealed cavity, the capillary core is arranged in the sealed cavity and separates the sealed cavity into a compensation cavity and a steam channel, the steam channel is connected with a first ejector and a second ejector, the compensation cavity is respectively communicated with the first ejector and the second ejector, one end of the condenser is respectively connected with the first ejector and the second ejector, the other end of the condenser is communicated with the compensation cavity, the control assembly is respectively connected with the second ejector and the chip, and the control assembly can control the on-off of the second ejector according to the temperature and the power of the chip. The heat dissipation device can increase the driving pressure of steam, reduce the temperature in the evaporator, enable the temperature of the evaporator to meet the standard and meet the heat dissipation requirement of a high-power chip.
Description
Technical Field
The invention relates to the technical field of electronic component heat dissipation, in particular to a multi-source driven high-power loop heat pipe heat dissipation device.
Background
The loop heat pipe has the advantages of strong heat transfer capability, long heat transfer distance and strong anti-gravity operation capability, and has great prospect in the aspect of heat management of a high heat flow density chip. The maximum heat transfer power of the loop heat pipe is limited by the capillary wick. The "leakage" of heat from the evaporator to the compensation chamber can in turn cause problems of start-up pulses, temperature fluctuations and even start-up failures. In the prior art, the ejector and the loop heat pipe are coupled, the boosting characteristic of the ejector is utilized to provide extra circulating driving force, and the ejection characteristic of the ejector is utilized to solve the problem of heat leakage of the compensation cavity.
However, the loop heat pipe is driven by a single ejector, and the evaporator can generate a large amount of steam under high heat flow density. Because the steam flow is limited by the minimum sectional area of a steam nozzle of the ejector, the steam cannot be quickly discharged from the bottom plate of the evaporator, the partial pressure of the steam in the steam channel is continuously increased, the temperature of the bottom plate exceeds the standard under high heat flow density, and the heat dissipation requirement of a high-power chip cannot be met. Although the steam discharge amount can be increased and the temperature of the bottom plate of the evaporator under high power can be reduced by enlarging the minimum sectional area (throat or outlet) of the steam nozzle of the ejector or increasing the number of the ejectors, the outlet of the steam nozzle can not reach sonic speed or supersonic speed under low power, the ejector loses ejection and pressure-boosting performance in a low-power operation interval, the heat transfer performance and stability of the loop heat pipe under low power are seriously influenced, the variable load operation requirement of a chip can not be met, and high-power equipment can not be ensured to operate under low power.
Disclosure of Invention
Based on this, it is necessary to provide a multi-source driven high-power loop heat pipe heat dissipation device, which can solve the technical problems that the temperature of an evaporator exceeds standard under high heat flux density and the heat dissipation requirement of a high-power chip cannot be met due to the driving of a single ejector in the prior art.
The invention provides a multi-source driven high-power loop heat pipe heat dissipation device, which is used for dissipating heat of a chip and comprises:
the capillary core is arranged in the sealed cavity and separates the sealed cavity into a compensation cavity and a steam channel, the steam channel is connected with a first ejector and a second ejector, and the compensation cavity is respectively communicated with the first ejector and the second ejector;
one end of the condenser is connected with the first ejector and the second ejector respectively, and the other end of the condenser is communicated with the compensation cavity; and
and the control assembly is respectively connected with the second ejector and the chip and can control the on-off of the second ejector according to the temperature and the power of the chip.
Furthermore, the heat dissipation device further comprises a conveying mechanism, the conveying mechanism is respectively connected with the compensation cavity, the steam channel, the first ejector, the second ejector and the condenser, and the conveying mechanism is used for enabling working media and steam to circularly flow among the compensation cavity, the steam channel, the first ejector, the second ejector and the condenser.
Furthermore, conveying mechanism includes first steam conduit, second steam conduit, first liquid pipeline and second liquid pipeline, the one end of first steam conduit with steam channel connects, the other end with second liquid pipeline connects, first ejector set up in first steam conduit, the one end of second steam conduit with steam channel connects, the other end with second liquid pipeline connects, the second ejector set up in second steam conduit, the one end of first liquid conduit with compensation chamber intercommunication, the other end respectively with first ejector with the second ejector is connected, second liquid conduit keeps away from the one end of first ejector with compensation chamber intercommunication, the condenser set up in second liquid pipeline.
Further, the control assembly comprises a controller and an electromagnetic valve, the controller is respectively connected with the electromagnetic valve and the chip, the electromagnetic valve is connected with the second ejector, and the controller is used for controlling the opening or closing of the electromagnetic valve according to the temperature and the power of the chip so as to control the on-off of the second ejector.
Further, the control assembly further comprises a temperature sensor, the temperature sensor is respectively connected with the controller, the temperature sensor is arranged on the chip and used for acquiring a temperature signal of the chip and transmitting the temperature signal to the controller, and the controller receives the temperature signal transmitted by the temperature sensor and controls the electromagnetic valve to be opened or closed according to the temperature signal.
Further, the judging step of the controller includes:
when the temperature of the chip is larger than a first threshold value and the power of the chip is larger than a second threshold value, the controller starts the second ejector;
when the temperature of the chip is smaller than a first threshold and the power of the chip is larger than a second threshold, the controller controls the second ejector to be in an open state;
and when the temperature of the chip is smaller than a first threshold and the power of the chip is smaller than a second threshold, the controller controls the second ejector to be in a closed state.
Furthermore, the average pore diameter of the capillary core is less than 5 μm, and the capillary core is formed by sintering metal powder.
Further, the preparation step of the capillary wick comprises:
drying metal powder with the particle size of less than 20 mu m in an oven and then uniformly spreading the metal powder into a die;
mixing a pore-forming agent with the particle size of 50-100 mu m into the metal powder;
cold-pressing and molding the metal powder in the die by a tablet press, and demolding after cold pressing, wherein the pressure of the cold pressing is more than 200MPa;
putting the demolded intermediate into a nitrogen atmosphere furnace for sintering, wherein the heating rate is 10 ℃/min, the heat is preserved for 30-90 min, and the intermediate is taken out after being cooled to the room temperature;
and putting the intermediate cooled to room temperature into deionized water for ultrasonic cleaning, and drying the cleaned intermediate to form the capillary core.
Further, the first ejector comprises a first steam nozzle and a first liquid nozzle, a first mixing cavity is formed in the first ejector, the first steam nozzle and the first liquid nozzle are communicated with the first mixing cavity, the steam channel is communicated with the first steam nozzle, steam in the steam channel can enter the first steam nozzle, and the first liquid pipeline is communicated with the first mixing cavity.
Further, the first steam nozzle is a convergent nozzle.
According to the multi-source driven high-power loop heat pipe heat dissipation device, the chip can generate heat when working, the heat is transferred to the capillary core, the temperature of the working medium in the capillary core rises after absorbing the heat to form steam, the steam enters the first ejector and the second ejector through the steam channel, and the control assembly can control the second ejector to be switched on and off according to the temperature and the power of the chip. When the temperature and the power of the chip are higher, the control assembly starts the second ejector, and the first ejector and the second ejector work simultaneously, so that the driving pressure of steam can be increased, the steam in the evaporator can be quickly exhausted, the steam partial pressure in the evaporator is reduced, and the temperature in the evaporator is reduced; when the temperature and the power of the chip are lower, the control assembly closes the second ejector, steam enters the condenser through the first ejector, the outlet of the steam nozzle reaches sonic speed or supersonic speed in low power, the ejector keeps ejection and boosting performance in a low-power operation interval, the heat transfer performance and the stability of the loop heat pipe under low power are guaranteed, the variable load operation requirement of the chip is met, namely the heat dissipation of the high-power chip operating under low power is met, the temperature of the evaporator can meet the standard, and the high-power chip can meet the heat dissipation requirement when operating under high power and low power.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a multi-source driven high-power loop heat pipe heat dissipation device according to an embodiment of the present invention;
FIG. 2 is another schematic structural diagram of a multi-source driven high-power loop heat pipe heat dissipation device according to an embodiment of the present invention;
FIG. 3 is a diagram illustrating a control method of the controller according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a capillary wick bubble breaking according to an embodiment of the present invention;
fig. 5 is a microstructure view of a metal powder sintered wick according to an embodiment of the present invention;
fig. 6 is a graph of pore size distribution for a metal powder sintered wick according to an embodiment of the present invention.
The main components are as follows:
100. an evaporator; 110. a housing; 120. a capillary core; 130. a steam channel; 140. a compensation chamber; 301. a capillary meniscus; 200. a first ejector; 210. a first steam nozzle; 220. a first liquid nozzle; 230. a first mixing chamber; 300. a second ejector; 310. a first steam nozzle; 320. a second liquid nozzle; 330. a second mixing chamber; 400. a condenser; 410. a second fin; 420. a fan; 510. a controller; 520. an electromagnetic valve; 530. a temperature sensor; 610. a first steam line; 620. a second steam line; 630. a first liquid conduit; 631. a first fin; 640. a second liquid conduit; 700. a chip; 800. a thermal interface material.
The implementation, functional features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all directional indicators (such as up, down, left, right, front, back \8230;) in the embodiments of the present invention are only used to explain the relative positional relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, "and/or" in the whole text includes three schemes, taking a and/or B as an example, including a technical scheme, and a technical scheme that a and B meet simultaneously; in addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
As shown in fig. 1 and fig. 2, in some embodiments, a multi-source driven high-power loop heat pipe heat dissipation device is used for dissipating heat of a chip 700, and includes an evaporator 100, a condenser 400 and a control component, where the evaporator 100 is used for absorbing heat dissipated by the chip 700, the evaporator 100 includes a casing 110 and a capillary core 120, the capillary core 120 can be filled with a working medium, the casing 110 has a sealed cavity, the capillary core 120 is disposed in the sealed cavity and separates the sealed cavity into a compensation cavity 140 and a steam channel 130, the steam channel 130 is connected to a first ejector 200 and a second ejector 300, and the compensation cavity 140 is respectively communicated with the first ejector 200 and the second ejector 300. One end of the condenser 400 is connected to the first ejector 200 and the second ejector 300, respectively, and the other end is communicated with the compensation chamber 140. The control assembly is respectively connected with the second ejector 300 and the chip 700, and the control assembly can control the on-off of the second ejector 300 according to the temperature and the power of the chip 700.
The chip 700 can generate heat during operation, the heat is transferred to the capillary core 120, the temperature of the working medium in the capillary core 120 rises after absorbing the heat, steam is formed, the steam enters the first ejector 200 and the second ejector 300 through the steam channel 130, and the control assembly can control the on-off of the second ejector 300 according to the temperature and the power of the chip 700. When the temperature and power of the chip 700 are low, the control assembly closes the second ejector 300 and the steam enters the condenser 400 through the first ejector 200. When the temperature and the power of chip 700 are higher, the second ejector 300 is opened to the control assembly, through first ejector 200 and the simultaneous working of second ejector 300, can increase the driving pressure of steam to make the steam in the evaporimeter 100 can disperse fast, reduce the steam partial pressure in the evaporimeter 100, reduce the temperature in the evaporimeter 100, make the temperature of evaporimeter 100 can accord with the standard, satisfy high-power chip 700's heat dissipation demand. In addition, when the high-power chip works, the through-flow capacity of steam can be greatly improved through the first ejector 200 and the second ejector 300, so that the loop heat pipe radiating device can be compatible with low-boiling-point working media, the application and storage environment temperature range of the loop heat pipe radiating device is expanded, the safety and reliability of the loop heat pipe radiating device in the use process are improved, when the low-power chip works, the first ejector 200 and the second ejector work simultaneously, namely, the sectional area of a steam nozzle is enlarged, the outlet of the steam nozzle cannot reach sonic speed or supersonic speed, and the effects of high-power equipment and low-power operation can be achieved through the matching of the control assembly.
Moreover, the loop heat pipe heat dissipation device needs to meet the storage and operation requirements of high and low temperature environments (-40 to +40 ℃), and the civil field also needs working media to be non-toxic and non-flammable. Wherein, the requirement of high and low temperature storage excludes water which is a working medium with excellent heat exchange performance, and the requirement of innocuity and nonflammability excludes alcohols and ammonia working media. Working media with low boiling points (such as electronic fluorinated liquid HFE7100, FC72, freon R134a, R22 and the like) can simultaneously meet the requirements. However, the latent heat of vaporization of the low-boiling point working medium is generally in the range of 1/10-1/20 of the water working medium, the low-boiling point working medium generates a large amount of steam under the same heat dissipation power, and the single ejector scheme cannot meet the requirements of steam through-flow and discharge, so that the temperature of the evaporator 100 is easily and rapidly increased.
In addition, the multi-source driven high-power loop heat pipe heat dissipation device can greatly improve the steam through-flow capacity, so that the loop heat pipe heat dissipation device is compatible with a low-boiling-point working medium, the application and storage environment temperature range of the loop heat pipe is expanded, and the safety and reliability of the loop heat pipe heat dissipation device in the use process are improved (the low-boiling-point working medium has the advantages of high insulativity, no toxicity, incombustibility and the like).
According to the multi-source-driven high-power loop heat pipe radiating device, the first ejector 200 is only started under the low power of the chip 700, and the heat transfer performance and stability of the loop heat pipe under the low power of the chip 700 are guaranteed. The second ejector 300 is started under the high power of the chip 700, so that the flow of steam and cold liquid is greatly improved, and the heat transfer limit of the loop heat pipe and the heat dissipation performance of the high power chip 700 are effectively improved. Therefore, the multi-source driven high-power loop heat pipe can meet the requirement of variable-load operation heat dissipation of the high-power chip 700.
Specifically, the heat dissipation device further comprises a conveying mechanism, the conveying mechanism is respectively connected with the compensation cavity 140, the steam channel 130, the first ejector 200, the second ejector 300 and the condenser 400, and the conveying mechanism is used for enabling working medium and steam to circularly flow among the compensation cavity 140, the steam channel 130, the first ejector 200, the second ejector 300 and the condenser 400.
More specifically, the conveying mechanism comprises a first steam pipeline 610, a second steam pipeline 620, a first liquid pipeline 630 and a second liquid pipeline 640, one end of the first steam pipeline 610 is connected with the steam channel 130, the other end of the first steam pipeline 610 is connected with the second liquid pipeline 640, the first ejector 200 is arranged on the first steam pipeline 610, one end of the second steam pipeline 620 is connected with the steam channel 130, the other end of the second steam pipeline is connected with the second liquid pipeline 640, the second ejector 300 is arranged on the second steam pipeline 620, one end of the first liquid pipeline 630 is communicated with the compensation cavity 140, the other end of the first liquid pipeline is respectively connected with the first ejector 200 and the second ejector 300, one end of the second liquid pipeline 640 far away from the first ejector 200 is communicated with the compensation cavity 140, and the condenser 400 is arranged on the second liquid pipeline 640. Specifically, the first liquid pipe 630 is further provided with a first fin 631.
During operation, steam in the steam channel 130 simultaneously enters the first steam pipeline 610 and the second steam pipeline 620 and respectively enters the first ejector 200 and the second ejector 300, cold liquid in the compensation chamber 140 respectively enters the first ejector 200 and the second ejector 300 through the first liquid pipeline 630, high-speed steam is formed by pressurization through the first ejector 200 and the second ejector 300 through evaporation, the high-speed steam and the cold liquid are mixed in the first ejector 200 and the second ejector 300 to form supersonic gas-liquid two-phase flow, and condensation shock waves are formed in the first ejector 200 and the second ejector 300, so that high-pressure hot liquid flows out of the first ejector 200 and the second ejector 300 and is converged from the first steam pipeline 610 and the second steam pipeline 620 into the second liquid pipeline 640 respectively, and the high-pressure hot liquid is condensed through the condenser 400 to form cold liquid, and the cold liquid flows into the compensation chamber 140. The majority of the cold fluid flowing into the compensation chamber 140 flows into the first and second ejectors 200, 300 under the suction of the first and second ejectors 200, 300, and absorbs heat and entrains air bubbles on the upper surface of the capillary wick 120. A small part of cold liquid passes through the capillary core 120 under the action of capillary force and gravity to become a filling working medium of the capillary core 120, and the working medium in the capillary core 120 is evaporated into steam under the action of heat dissipated by the chip 700, so that the steam and the liquid circularly flow among the compensation cavity 140, the evaporation channel, the first ejector 200, the second ejector 300 and the condenser 400.
Specifically, the condenser 400 is a serpentine tube condenser. The second liquid pipe 640 is further provided with a second fin 410 and a fan 420 to increase the condensing effect of the condenser 400. The bottom of the vaporizer 100 is closely attached to the chip 700 by the thermal interface material 800. More specifically, the first ejector 200 and the second ejector 300 have the same structure.
Further, first ejector 200 includes first steam nozzle 210 and first liquid nozzle 220, and first mixing chamber 230 has been seted up to first ejector 200, and first steam nozzle 210 and first liquid nozzle 220 all are linked together with first mixing chamber 230, and first liquid nozzle 220 sets up in the outside of first steam nozzle 210, and steam channel 130 communicates with first steam nozzle 210 to make the steam in the steam channel 130 can get into first steam nozzle 210, first liquid pipeline 630 and first mixing chamber 230 intercommunication.
Further, the second ejector 300 comprises a second steam nozzle 310 and a second liquid nozzle 320, the second mixing cavity 330 is formed in the second ejector 300, the second steam nozzle 310 and the second liquid nozzle 320 are communicated with the second mixing cavity 330, the second liquid nozzle 320 is arranged on the outer side of the second steam nozzle 310, the steam channel 130 is communicated with the second steam nozzle 310, steam in the steam channel 130 can enter the second steam nozzle 310, and the second liquid pipeline 640 is communicated with the second mixing cavity 330.
Further, the first vapor nozzle 210 and the second vapor nozzle 310 are preferably convergent nozzles, which aim to prevent vapor from condensing during expansion and affecting loop heat pipe heat dissipation performance, mainly due to: the steam generated by the evaporator 100 is generally in a saturated state, and if a traditional ejector taking steam as primary fluid and a steam nozzle as a convergent-divergent structure is adopted, after the saturated steam flows through the throat part of the convergent-divergent nozzle, supercooling is probably generated in an expansion section due to shock waves, so that part of the steam is condensed in the steam nozzle, the performance of the ejector is greatly influenced, and the performance of a loop heat pipe is further influenced.
Further, the control assembly comprises a controller 510 and a solenoid valve 520, the controller 510 is respectively connected with the solenoid valve 520 and the chip 700, the solenoid valve 520 is connected with the second ejector 300, the solenoid valve 520 is arranged on the second steam pipeline 620 and is located between the steam channel 130 and the second ejector 300, and the controller 510 is used for controlling the opening or closing of the solenoid valve 520 according to the temperature and the power of the chip 700, so as to control the on-off of the second ejector 300. Specifically, the controller 510 may be, but is not limited to, a PID controller 510.
Furthermore, the control assembly further includes temperature sensors 530, the temperature sensors 530 are respectively connected to the controller 510, the temperature sensors 530 are disposed on the chip 700, the temperature sensors 530 are configured to acquire temperature signals of the chip 700 and transmit the temperature signals to the controller 510, and the controller 510 receives the temperature signals transmitted by the temperature sensors 530 and controls the opening or closing of the solenoid valve 520 according to the temperature signals. Specifically, the temperature sensor 530 may be provided in plural, and the plural temperature sensors 530 simultaneously acquire the temperature signals of the chip 700 and average the temperature signals, thereby improving the accuracy of temperature measurement. Preferably, the temperature sensors 530 may be provided in two.
In some embodiments, the determining step of the controller 510 includes:
when the temperature of the chip 700 is greater than the first threshold and the power of the chip 700 is greater than the second threshold, the controller 510 starts the second ejector 300;
when the temperature of the chip 700 is smaller than the first threshold and the power of the chip 700 is larger than the second threshold, the controller 510 controls the second ejector 300 to be in an open state;
when the temperature of the chip 700 is less than the first threshold and the power of the chip 700 is less than the second threshold, the controller 510 controls the second injector 300 to be in the off state. Wherein the first threshold is 85 ℃.
As shown in fig. 3, specifically, when the heating power Q of the chip 700 is greater than the second threshold Q1, and the arithmetic average value Tave of the temperature T1 measured by the first temperature sensor 530 and the temperature T2 measured by the second temperature sensor 530 is greater than 85 ℃, the PID controller 510 sends a pulse signal to open the electromagnetic valve 520, so that the first ejector 200 and the second ejector 300 operate simultaneously, the loop heat pipe heat dissipation device enters the dual ejector operating mode, the steam through-flow capacity is greatly improved, and the temperature of the chip 700 is rapidly reduced. When Tave <85 ℃, Q > Q1, the PID controller 510 continues to act, maintaining the solenoid valve 520 in a normally open state. When Tave is less than 85 ℃ and Q is less than Q1, the PID controller 510 does not send out pulse signals, the valve 9 is maintained in a normally closed state, the first ejector 200 is opened, the second ejector 300 is closed, and the loop heat pipe heat dissipation device enters a single ejector working mode.
The mathematical expression of the PID controller 510 is
In formula (1): e (t) is the system deviation, kp is the proportional control parameter, KI is the integral control parameter, and Kd is the derivative control parameter. The three parameters are optimized and selected according to the actual loop heat pipe heat dissipation device.
Further, in the feedback loop of the PID controller 510, the input signal is the average temperature Teva and the heating power Q of the chip 700, and the output signal is a pulse electrical signal for controlling the opening or closing of the electromagnetic valve 520.
As shown in fig. 4, the working medium with a low boiling point often has a low surface tension (about 1/4-1/5 of water), and according to Young-Laplace equation (formula 2), when the same capillary core 120 is used (the effective pore diameter is the same), the "bubble breaking pressure" is much lower than that of water, and part of steam easily passes through the capillary core 120 and enters the compensation cavity 140, so that the evaporator 100 cannot realize gas-liquid phase separation, and problems such as start pulse, temperature fluctuation, start failure and the like are easily caused. The low boiling point insulating liquid has a lower capillary force, which means that the head on the liquid side of the capillary meniscus 301 is lower when the working substance changes phase between the pores of the capillary wick 120. At high heating power, the gas side partial pressure is higher than the liquid side partial pressure (i.e. capillary head) and the capillary meniscus 301 will move towards the compensation chamber 140, creating a "bubble break". The "bubble breaking" causes the pressure and temperature of the compensation chamber 140 to increase, which affects the liquid backflow, and eventually causes the loop heat pipe to fail to start.
In the formula (2): Δ P-bubble breaking pressure, kPa; σ -surface tension, N/m; theta-contact angle; r is eff The capillary wick 120 effective pore size, m.
In some embodiments, the capillary wick 120 has an average pore size of less than 5 μm and is sintered from a metal powder. According to the formula (2), the small-aperture capillary core 120 can generate a large capillary pressure head, so that the bubble breaking phenomenon is effectively prevented, and the working medium with low boiling point and low surface tension can be suitable for the loop heat pipe.
Specifically, the preparation steps of the capillary wick 120 include:
s1, uniformly spreading metal powder with the particle size of less than 20 microns into a die after drying in an oven. The material of the metal powder may be copper, nickel, stainless steel, or the like.
S2, mixing a pore-forming agent with the particle size of 50-100 μm into the metal powder to improve the porosity of the metal powder sintering capillary core 120. Wherein the pore-forming agent is NaCl or Na 2 CO 3 And salts that are readily soluble in water.
And S3, performing cold press molding on the metal powder in the die through a tablet press, and demolding after cold press to ensure that the capillary core 120 has a smaller effective pore size. Wherein the pressure of cold pressing is more than 200MPa.
And S4, sintering the demolded intermediate in a nitrogen atmosphere furnace at a heating rate of 10 ℃/min for 30-90 min, and cooling the intermediate to room temperature and then taking out.
And S5, placing the intermediate cooled to room temperature into deionized water for ultrasonic cleaning, and drying the cleaned intermediate to form the capillary core 120.
As shown in fig. 5 and fig. 6, the small-pore-diameter metal powder sintered capillary core 120 prepared by the above preparation steps has a compact pore structure, and statistics show that the effective pore diameter is less than 5 μm, and most of the micropores have diameters distributed in the range of 1 to 2 μm, so that a larger capillary head can be provided, and the bubble breaking phenomenon can be delayed.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A high-power loop heat pipe heat abstractor of multisource driven for dispel the heat to the chip, its characterized in that includes:
the capillary core is arranged in the sealed cavity and separates the sealed cavity into a compensation cavity and a steam channel, the steam channel is connected with a first ejector and a second ejector, and the compensation cavity is respectively communicated with the first ejector and the second ejector;
one end of the condenser is connected with the first ejector and the second ejector respectively, and the other end of the condenser is communicated with the compensation cavity; and
and the control assembly is respectively connected with the second ejector and the chip and can control the on-off of the second ejector according to the temperature and the power of the chip.
2. The heat dissipation device of claim 1, further comprising a delivery mechanism, wherein the delivery mechanism is connected to the compensation chamber, the steam channel, the first ejector, the second ejector, and the condenser, respectively, and is configured to allow working medium and steam to circulate among the compensation chamber, the steam channel, the first ejector, the second ejector, and the condenser.
3. The heat dissipation device according to claim 2, wherein the conveying mechanism includes a first steam pipeline, a second steam pipeline, a first liquid pipeline and a second liquid pipeline, one end of the first steam pipeline is connected to the steam channel, the other end of the first steam pipeline is connected to the second liquid pipeline, the first ejector is disposed in the first steam pipeline, one end of the second steam pipeline is connected to the steam channel, the other end of the second steam pipeline is connected to the second liquid pipeline, the second ejector is disposed in the second steam pipeline, one end of the first liquid pipeline is communicated with the compensation cavity, the other end of the first liquid pipeline is respectively connected to the first ejector and the second ejector, one end of the second liquid pipeline, which is far away from the first ejector, is communicated with the compensation cavity, and the condenser is disposed in the second liquid pipeline.
4. The heat dissipation device of claim 1, wherein the control assembly comprises a controller and a solenoid valve, the controller is respectively connected with the solenoid valve and the chip, the solenoid valve is connected with the second ejector, and the controller is used for controlling the opening or closing of the solenoid valve according to the temperature and the power of the chip so as to control the on-off of the second ejector.
5. The heat dissipation device of claim 4, wherein the control assembly further comprises temperature sensors, the temperature sensors are respectively connected to the controller, and the temperature sensors are disposed on the chip, the temperature sensors are configured to obtain temperature signals of the chip and transmit the temperature signals to the controller, and the controller receives the temperature signals transmitted by the temperature sensors and controls the solenoid valve to be turned on or off according to the temperature signals.
6. The heat dissipating device of claim 1, wherein the controller determines that the step of determining comprises:
when the temperature of the chip is greater than a first threshold value and the power of the chip is greater than a second threshold value, the controller starts the second ejector;
when the temperature of the chip is smaller than a first threshold and the power of the chip is larger than a second threshold, the controller controls the second ejector to be in an open state;
and when the temperature of the chip is smaller than a first threshold and the power of the chip is smaller than a second threshold, the controller controls the second ejector to be in a closed state.
7. The heat sink of claim 1, wherein the wick has an average pore size of less than 5 μm and is sintered from a metal powder.
8. The heat sink of claim 7, wherein the step of preparing the capillary wick comprises:
drying metal powder with the particle size of less than 20 mu m in an oven and then uniformly spreading the metal powder into a die;
mixing a pore-forming agent with the particle size of 50-100 mu m into the metal powder;
cold-pressing and molding the metal powder in the die by a tablet press, and demolding after cold pressing, wherein the pressure of the cold pressing is more than 200MPa;
putting the demolded intermediate into a nitrogen atmosphere furnace for sintering, wherein the heating rate is 10 ℃/min, the heat is preserved for 30-90 min, and the intermediate is taken out after being cooled to the room temperature;
and putting the intermediate cooled to room temperature into deionized water for ultrasonic cleaning, and drying the cleaned intermediate to form the capillary core.
9. The heat dissipation device of claim 1, wherein the first ejector includes a first steam nozzle and a first liquid nozzle, the first ejector defines a first mixing chamber, the first steam nozzle and the first liquid nozzle are both in communication with the first mixing chamber, the steam channel is in communication with the first steam nozzle such that steam in the steam channel can enter the first steam nozzle, and the first liquid conduit is in communication with the first mixing chamber.
10. The heat dissipation device of claim 9, wherein the first steam nozzle is a converging nozzle.
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| CN102359745A (en) * | 2011-07-06 | 2012-02-22 | 罗勰 | Moderate and low temperature mixed working medium thermal and electrical combined cycle based on brown cycle |
| DE202017100039U1 (en) * | 2017-01-06 | 2017-03-14 | Shanghai Ocean University | Jet self-cascade refrigeration system for residual heat recovery of a tuna fishing boat |
| US20200292244A1 (en) * | 2019-03-12 | 2020-09-17 | Xi`an Jiaotong University | Loop heat pipe with vapor-liquid two-phase flow injector |
| CN112179188A (en) * | 2020-09-25 | 2021-01-05 | 西安交通大学 | Flat plate type loop heat pipe capable of stably running under high heat leakage and using method |
| CN114772674A (en) * | 2022-05-09 | 2022-07-22 | 南京工业大学 | Low-carbon running saline wastewater treatment system and method applying solar energy and loop heat pipe |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102359745A (en) * | 2011-07-06 | 2012-02-22 | 罗勰 | Moderate and low temperature mixed working medium thermal and electrical combined cycle based on brown cycle |
| DE202017100039U1 (en) * | 2017-01-06 | 2017-03-14 | Shanghai Ocean University | Jet self-cascade refrigeration system for residual heat recovery of a tuna fishing boat |
| US20200292244A1 (en) * | 2019-03-12 | 2020-09-17 | Xi`an Jiaotong University | Loop heat pipe with vapor-liquid two-phase flow injector |
| CN112179188A (en) * | 2020-09-25 | 2021-01-05 | 西安交通大学 | Flat plate type loop heat pipe capable of stably running under high heat leakage and using method |
| CN114772674A (en) * | 2022-05-09 | 2022-07-22 | 南京工业大学 | Low-carbon running saline wastewater treatment system and method applying solar energy and loop heat pipe |
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