CN115307469B - Multi-source driven high-power loop heat pipe radiating device - Google Patents

Abstract

The invention discloses a multi-source driven high-power loop heat pipe radiating device which is used for radiating a chip and comprises an evaporator, a condenser and a control component, wherein the evaporator is used for absorbing heat radiated by the chip and comprises a shell and a capillary core, the capillary core can be filled with working media, the shell is provided with a sealing cavity, the capillary core is arranged in the sealing cavity and isolates the sealing 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 respectively communicated with the compensation cavity, the control component is respectively connected with the second ejector and the chip, and the control component 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 and reduce the temperature in the evaporator, so that the temperature of the evaporator can meet the standard, and the heat dissipation requirement of a high-power chip is met.

Description

A multi-source driven high-power loop heat pipe cooling device

Technical field

The invention relates to the technical field of heat dissipation of electronic components, and in particular to a multi-source driven high-power loop heat pipe heat dissipation device.

Background technique

Loop heat pipes have strong heat transfer capabilities, long heat transmission distances, and strong anti-gravity operation capabilities. They are very promising in thermal management of high heat flow density chips. However, the maximum heat transfer power of the loop heat pipe is limited by the capillary core. The "heat leakage" of the evaporator to the compensation chamber will cause problems such as starting pulses, temperature fluctuations and even starting failures. In the existing technology, the idea of coupling an ejector to a loop heat pipe is used, and the boost characteristics of the ejector are used to provide additional cycle driving force, and its ejector characteristics are used to solve the problem of "heat leakage" in the compensation cavity.

But the loop heat pipe is driven by a single ejector, and under high heat flux density, the evaporator will generate a large amount of steam. Since the steam flow rate is limited by the minimum cross-sectional area of the steam nozzle of the ejector, it cannot be quickly discharged from the evaporator bottom plate. The steam partial pressure in the steam channel continues to increase, causing the bottom plate temperature to exceed the standard under high heat flux density, which cannot meet the requirements of high-power chips. cooling requirements. Although it is possible to increase the steam discharge and reduce the evaporator bottom plate temperature at high power by expanding the minimum cross-sectional area (throat or outlet) of the steam nozzle of the ejector or increasing the number of ejector, it will also make the steam at low power The nozzle outlet cannot reach the speed of sound or supersonic speed, causing the ejector to lose the ejector and boost performance in the low-power operating range, seriously affecting the heat transfer performance and stability of the loop heat pipe at low power, and being unable to meet the variable load of the chip. Operation requirements, it is impossible to guarantee that high-power equipment will operate at low power.

Contents of the invention

Based on this, it is necessary to provide a high-power loop heat pipe cooling device driven by multiple sources, which can solve the problem in the existing technology of being driven by a single ejector, causing the evaporator temperature to exceed the standard under high heat flux density, which cannot meet the needs of high-power chips. technical issues of cooling requirements.

The invention provides a multi-source driven high-power loop heat pipe cooling device for heat dissipating chips, including:

Evaporator, the evaporator is used to absorb the heat emitted by the chip, the evaporator includes a shell and a capillary wick, the capillary wick can be filled with working medium, the shell has a sealed cavity, the capillary wick is provided in the sealed cavity, and isolates the sealed cavity into a compensation chamber and a steam channel. The steam channel is connected to a first ejector and a second ejector, and the compensation chamber is connected to the The first ejector is connected to the second ejector;

A condenser, one end of the condenser is connected to the first ejector and the second ejector respectively, and the other end is connected to the compensation chamber; and

A control component, the control component is connected to the second emitter and the chip respectively, and the control component can control the on/off of the second emitter according to the temperature and power of the chip.

Further, the heat dissipation device further includes a transport mechanism, which is respectively connected to the compensation chamber, the steam channel, the first ejector, the second ejector and the condenser. , the conveying mechanism is used for circulating working fluid and steam between the compensation chamber, the steam channel, the first ejector, the second ejector and the condenser.

Further, the delivery mechanism includes a first steam pipe, a second steam pipe, a first liquid pipe and a second liquid pipe. One end of the first steam pipe is connected to the steam channel, and the other end is connected to the third steam channel. Two liquid pipes are connected, the first ejector is arranged on the first steam pipe, one end of the second steam pipe is connected to the steam channel, and the other end is connected to the second liquid pipe, the The second ejector is provided in the second steam pipe, one end of the first liquid pipe is connected to the compensation chamber, and the other end is connected to the first ejector and the second ejector respectively, One end of the second liquid pipe away from the first ejector is connected to the compensation chamber, and the condenser is disposed on the second liquid pipe.

Further, the control component includes a controller and a solenoid valve, the controller is connected to the solenoid valve and the chip respectively, the solenoid valve is connected to the second ejector, and the controller is used according to The temperature and power of the chip are used to control the opening or closing of the solenoid valve, and further to control the on-off of the second ejector.

Further, the control component further includes a temperature sensor, the temperature sensor is respectively connected to the controller, and the temperature sensor is arranged on the chip, and the temperature sensor is used to obtain the temperature signal of the chip, And transmit the temperature signal to the controller, the controller receives the temperature signal transmitted by the temperature sensor, and controls the opening or closing of the solenoid valve according to the temperature signal.

Further, the controller's judgment steps include:

When the temperature of the chip is greater than the first threshold and the power of the chip is greater than the second threshold, the controller turns on the second emitter;

When the temperature of the chip is less than the first threshold and the power of the chip is greater than the second threshold, the controller controls the second emitter to be in an open state;

When the temperature of the chip is less than the first threshold and the power of the chip is less than the second threshold, the controller controls the second emitter to be in a closed state.

Further, the average pore diameter of the capillary core is less than 5 μm and is made of sintered metal powder.

Further, the preparation steps of the capillary core include:

The metal powder with a particle size less than 20 μm is evenly spread into the mold after drying in an oven;

Mix a 50-100 μm pore-forming agent into the metal powder;

The metal powder in the mold is cold-pressed and formed by a tablet press, and demolded after cold-pressing, wherein the cold-pressing pressure is greater than 200 MPa;

Put the demolded intermediate into a nitrogen atmosphere furnace for sintering, with a heating rate of 10°C/min and heat preservation for 30 to 90 minutes. The intermediate is cooled to room temperature and then taken out;

The intermediate after cooling to room temperature is placed in deionized water for ultrasonic cleaning, and the cleaned intermediate is dried to form the capillary core.

Further, the first ejector includes a first steam nozzle and a first liquid nozzle, the first ejector is provided with a first mixing chamber, and the first steam nozzle and the first liquid nozzle are connected with each other. The first mixing chamber is connected, the steam channel is connected with the first steam nozzle, so that the steam in the steam channel can enter the first steam nozzle, and the first liquid pipe is connected with the first steam nozzle. The first mixing chamber is connected to the first mixing chamber.

Further, the first steam nozzle is a tapering nozzle.

The invention provides a multi-source driven high-power loop heat pipe cooling device. The chip generates heat when working, and the heat is transferred to the capillary core. The temperature of the working fluid in the capillary core rises after absorbing the heat, forming steam. The steam passes through the steam. The channel enters the first ejector and the second ejector, and the control component can control the on/off of the second ejector according to the chip temperature and power. When the temperature and power of the chip are high, the control component turns on the second ejector. By working the first ejector and the second ejector simultaneously, the driving pressure of the steam can be increased so that the steam in the evaporator can quickly Discharge, reduce the partial pressure of steam in the evaporator, thereby reducing the temperature in the evaporator; when the temperature and power of the chip are low, the control component closes the second ejector, and the steam enters the condenser through the first ejector. It enables the steam nozzle outlet to reach sonic or supersonic speed at low power, enables the ejector to maintain ejection and boost performance in the low power operating range, ensures the heat transfer performance and stability of the loop heat pipe at low power, and meets the requirements of the chip. The variable load operation requirement is to meet the heat dissipation requirements of high-power chips operating at low power, so that the temperature of the evaporator can meet the standards, and the high-power chip can meet the heat dissipation requirements when operating at high power and low power.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a multi-source driven high-power loop heat pipe cooling device according to an embodiment of the present invention;

Figure 2 is another structural schematic diagram of a multi-source driven high-power loop heat pipe cooling device according to an embodiment of the present invention;

Figure 3 is a control method diagram of the controller according to the embodiment of the present invention;

Figure 4 is a schematic diagram of capillary core bubble breaking according to an embodiment of the present invention;

Figure 5 is a microstructure diagram of a metal powder sintered capillary core according to an embodiment of the present invention;

Figure 6 is a pore size distribution diagram of the metal powder sintered capillary core according to the embodiment of the present invention.

Main components:

100. Evaporator; 110. Shell; 120. Capillary core; 130. Steam channel; 140. Compensation chamber; 301. Capillary meniscus; 200. First ejector; 210. First steam nozzle; 220. First liquid nozzle; 230, first mixing chamber; 300, second ejector; 310, first steam nozzle; 320, second liquid nozzle; 330, second mixing chamber; 400, condenser; 410, second Fin; 420, fan; 510, controller; 520, solenoid valve; 530, temperature sensor; 610, first steam pipe; 620, second steam pipe; 630, first liquid pipe; 631, first fin; 640. Second liquid pipeline; 700. Chip; 800. Thermal interface material.

The realization of the purpose, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiment of the present invention are only used to explain the relationship between components in a specific posture (as shown in the drawings). Relative positional relationship, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly.

In addition, descriptions involving "first", "second", etc. in the present invention are for descriptive purposes only and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In addition, "and/or" in the full text includes three solutions, taking A and/or B as an example, including technical solution A, technical solution B, and technical solutions that satisfy both A and B at the same time; in addition, between various embodiments, The technical solutions can be combined with each other, but it must be based on what a person of ordinary skill in the art can realize. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that this combination of technical solutions does not exist and is not required by the present invention. within the scope of protection.

As shown in Figures 1 and 2, in some embodiments, a multi-source driven high-power loop heat pipe cooling device is used to dissipate heat from the chip 700, including an evaporator 100, a condenser 400 and a control component. The evaporator 100 is used to absorb the heat emitted by the chip 700. The evaporator 100 includes a shell 110 and a capillary wick 120. The capillary wick 120 can be filled with working medium. The shell 110 has a sealed cavity. The capillary wick 120 is arranged in the sealed cavity and seals it. The cavity is separated into a compensation chamber 140 and a steam channel 130. The steam channel 130 is connected to the first ejector 200 and the second ejector 300. The compensation chamber 140 is connected to the first ejector 200 and the second ejector respectively. 300 connections. One end of the condenser 400 is connected to the first ejector 200 and the second ejector 300 respectively, and the other end is connected to the compensation chamber 140 . The control component is connected to the second emitter 300 and the chip 700 respectively, and the control component can control the on/off of the second emitter 300 according to the temperature and power of the chip 700 .

The chip 700 generates heat when working, and the heat is transferred to the capillary core 120. The temperature of the working fluid in the capillary core 120 rises after absorbing the heat, forming steam. The steam enters the first ejector 200 and the second ejector through the steam channel 130. The control component can control the on/off of the second emitter 300 according to the temperature and power of the chip 700 . When the temperature and power of the chip 700 are low, the control component closes the second ejector 300, and the steam enters the condenser 400 through the first ejector 200. When the temperature and power of the chip 700 are high, the control component turns on the second ejector 300. By working the first ejector 200 and the second ejector 300 at the same time, the driving pressure of the steam can be increased, so that the evaporator 100 The steam in the evaporator can be quickly discharged, reducing the partial pressure of the steam in the evaporator 100 and lowering the temperature in the evaporator 100, so that the temperature of the evaporator 100 can meet the standards and meet the heat dissipation requirements of the high-power chip 700. In addition, when the high-power chip is working, the flow capacity of steam can be greatly improved through the first ejector 200 and the second ejector 300, so that the loop heat pipe heat dissipation device can be compatible with low boiling point working fluids, which not only expands the loop The application and storage environment temperature range of the heat pipe heat dissipation device also improves the safety and reliability of the loop heat pipe heat dissipation device during use. When the low-power chip is working, if the first injector 200 and the second injector work at the same time, It is equivalent to expanding the cross-sectional area of the steam nozzle so that the outlet of the steam nozzle cannot reach the speed of sound or supersonic speed. Through the cooperation of the control components, the effect of high-power equipment and low-power operation can be achieved.

Furthermore, the loop heat pipe cooling device must meet the storage and operation requirements in high and low temperature environments (-40 ~ +40°C). The civilian field also requires that the working fluid is non-toxic and non-flammable. Among them, the requirements for high and low temperature storage exclude water, a working fluid with excellent heat exchange performance, while the non-toxic and non-flammable requirements exclude alcohol and ammonia working fluids. Low boiling point working fluids (such as electronic fluorinated fluid HFE7100, FC72, Freon R134a, R22, etc.) can meet the above requirements at the same time. However, the latent heat of vaporization of low-boiling-point working fluids is generally in the range of 1/10 to 1/20 of that of water working fluids. Under the same heat dissipation power, low-boiling point working fluids will generate a large amount of steam, and the single ejector solution will not be able to meet the steam flow requirements. Flow and dissipation requirements may easily cause the temperature of the evaporator 100 to rise sharply.

In addition, the multi-source driven high-power loop heat pipe cooling device of this application can greatly improve the steam flow capacity and is therefore compatible with low boiling point working fluids. It not only expands the application and storage environment temperature range of the loop heat pipe, but also improves the environmental protection. The safety and reliability of the heat pipe heat dissipation device during use (low boiling point working fluid has the advantages of high insulation, non-toxic and non-flammable).

A multi-source driven high-power loop heat pipe heat dissipation device of this application only turns on the first ejector 200 when the chip 700 is at low power, ensuring the heat transfer and stability of the loop heat pipe under the low power of the chip 700 sex. When the second ejector 300 is turned on when the chip 700 is at high power, the flow rates of steam and cold liquid are greatly increased, thereby effectively improving the heat transfer limit of the loop heat pipe and the heat dissipation performance of the high-power chip 700 . Therefore, the multi-source driven high-power loop heat pipe described in this application can meet the heat dissipation requirements of the high-power chip 700 during variable load operation.

Specifically, the heat dissipation device also includes a conveying mechanism, which is respectively connected to the compensation chamber 140, the steam channel 130, the first ejector 200, the second ejector 300 and the condenser 400. The conveying mechanism is used to supply working fluid and Steam circulates between the compensation chamber 140, the steam channel 130, the first ejector 200, the second ejector 300 and the condenser 400.

More specifically, the delivery mechanism includes a first steam pipe 610, a second steam pipe 620, a first liquid pipe 630 and a second liquid pipe 640. One end of the first steam pipe 610 is connected to the steam channel 130, and the other end is connected to the second steam channel 130. The liquid pipe 640 is connected, the first ejector 200 is disposed in the first steam pipe 610, one end of the second steam pipe 620 is connected to the steam channel 130, and the other end is connected to the second liquid pipe 640, and the second ejector 300 is disposed In the second steam pipe 620, one end of the first liquid pipe 630 is connected to the compensation chamber 140, and the other end is connected to the first ejector 200 and the second ejector 300 respectively. The second liquid pipe 640 is away from the first ejector. One end of 200 is connected to the compensation chamber 140, and the condenser 400 is disposed in the second liquid pipe 640. Specifically, the first fin 631 is also provided on the first liquid pipe 630 .

During operation, the steam in the steam channel 130 enters the first steam pipe 610 and the second steam pipe 620 at the same time, and enters the first ejector 200 and the second ejector 300 respectively. The cold liquid in the compensation chamber 140 passes through the first ejector 200 and the second ejector 300 . A liquid pipe 630 enters the first ejector 200 and the second ejector 300 respectively. The evaporation is pressurized through the first ejector 200 and the second ejector 300 to form high-speed steam. The high-speed steam and cold liquid are evaporated in the first ejector 200 and the second ejector 300. After mixing in the ejector 200 and the second ejector 300, a supersonic gas-liquid two-phase flow is formed, and a condensation shock wave is formed in the first ejector 200 and the second ejector 300, so that from the first ejector The high-pressure hot liquid comes out of the ejector 200 and the second ejector 300. The high-pressure hot liquid merges from the first steam pipe 610 and the second steam pipe 620 into the second liquid pipe 640, and is condensed through the condenser 400 to form cold water. Liquid, cold liquid flows into the compensation chamber 140. Most of the cold liquid flowing into the compensation chamber 140 flows into the first ejector 200 and the second ejector 300 under the suction of the first ejector 200 and the second ejector 300, and absorbs heat and takes away the capillary core. 120 bubbles on the upper surface. A small part of the cold liquid passes through the capillary core 120 under the action of capillary force and gravity, and becomes the filling working fluid of the capillary core 120. Under the action of the heat emitted by the chip 700, the working fluid in the capillary core 120 evaporates into steam, so that the steam and The liquid circulates between the compensation chamber 140, the evaporation channel, the first ejector 200, the second ejector 300 and the condenser 400.

Specifically, the condenser 400 is a serpentine condenser. The second liquid pipe 640 is also provided with a second fin 410 and a fan 420 to increase the condensation effect of the condenser 400 . The bottom of the evaporator 100 is closely connected to the chip 700 through the thermal interface material 800 . More specifically, the first ejector 200 and the second ejector 300 have the same structure.

Further, the first injector 200 includes a first steam nozzle 210 and a first liquid nozzle 220. The first injector 200 is provided with a first mixing chamber 230. The first steam nozzle 210 and the first liquid nozzle 220 are both connected with the first mixing chamber 230. A mixing chamber 230 is connected, the first liquid nozzle 220 is arranged outside the first steam nozzle 210, and the steam channel 130 is connected with the first steam nozzle 210, so that the steam in the steam channel 130 can enter the first steam nozzle 210 , the first liquid pipe 630 is connected with the first mixing chamber 230 .

Furthermore, the second injector 300 includes a second steam nozzle 310 and a second liquid nozzle 320. The second injector 300 is provided with a second mixing chamber 330. The second steam nozzle 310 and the second liquid nozzle 320 are both connected with The second mixing chamber 330 is connected, the second liquid nozzle 320 is arranged outside the second steam nozzle 310, and the steam channel 130 is connected with the second steam nozzle 310, so that the steam in the steam channel 130 can enter the second steam nozzle. 310. The second liquid pipe 640 is connected with the second mixing chamber 330.

Furthermore, the first steam nozzle 210 and the second steam nozzle 310 are preferably tapered nozzles. The purpose is to prevent the steam from condensing during the expansion process and affecting the heat dissipation performance of the loop heat pipe. The main reason is that the steam generated by the evaporator 100 is generally is in a saturated state. For example, if a traditional ejector with steam as the primary fluid and a steam nozzle as a scaling structure is used, after the saturated steam flows through the throat of the scaling nozzle, it is very likely that supercooling will occur in the expansion section due to the generation of shock waves, causing the Part of the steam condenses in the steam nozzle, which greatly affects the performance of the ejector and thus the loop heat pipe.

Further, the control component includes a controller 510 and a solenoid valve 520. The controller 510 is connected to the solenoid valve 520 and the chip 700 respectively. The solenoid valve 520 is connected to the second ejector 300. The solenoid valve 520 is disposed on the second steam pipe 620. , and is located between the steam channel 130 and the second ejector 300. The controller 510 is used to control the opening or closing of the solenoid valve 520 according to the temperature and power of the chip 700, thereby controlling the passage of the second ejector 300. Break. Specifically, the controller 510 may be, but is not limited to, a PID controller 510.

Furthermore, the control component also includes a temperature sensor 530. The temperature sensor 530 is connected to the controller 510 respectively. The temperature sensor 530 is disposed on the chip 700. The temperature sensor 530 is used to obtain the temperature signal of the chip 700 and transmit the temperature signal to Controller 510. The controller 510 receives the temperature signal transmitted by the temperature sensor 530, and controls the opening or closing of the solenoid valve 520 according to the temperature signal. Specifically, multiple temperature sensors 530 may be provided, and the multiple temperature sensors 530 simultaneously obtain the temperature signals of the chip 700 and average them, thereby improving the accuracy of temperature measurement. Preferably, two temperature sensors 530 may be provided.

In some embodiments, the determination steps of the controller 510 include:

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 turns on the second emitter 300;

When the temperature of the chip 700 is less than the first threshold and the power of the chip 700 is greater than the second threshold, the controller 510 controls the second ejector 300 to be in an on 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 emitter 300 to be in a closed state. Among them, the first threshold is 85°C.

As shown in Figure 3, specifically, when the heating power Q of the chip 700 is greater than the second threshold Q1, and the arithmetic mean Tave of the temperature T1 measured by the first temperature sensor 530 and the temperature T2 measured by the second temperature sensor 530 is >85°C , the PID controller 510 sends a pulse signal to open the solenoid valve 520, the first ejector 200 and the second ejector 300 work at the same time, the loop heat pipe cooling device enters the dual ejector working mode, and the steam flow capacity is greatly improved. , causing the temperature of the chip 700 to drop rapidly. When Tave<85°C and Q>Q1, the PID controller 510 continues to operate and maintains the solenoid valve 520 in the normally open state. When Tave<85℃, Q<Q1, the PID controller 510 does not send out a pulse signal and maintains the valve 9 in a normally closed state. The first ejector 200 is opened, the second ejector 300 is closed, and the loop heat pipe cooling device enters Single emitter working mode.

The mathematical expression of 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 differential control parameter. The three parameters should be optimized and selected based on the actual loop heat pipe cooling 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 that controls the opening or closing of the solenoid valve 520.

As shown in Figure 4, low-boiling point working fluids tend to have lower surface tension (about 1/4 to 1/5 of water). According to the Young-Laplace equation (Equation 2), when using the same capillary core 120 (effective pore diameter Same), its "bubble breaking pressure" is much lower than that of water, and part of the steam easily passes through the capillary wick 120 and enters the compensation chamber 140, making it impossible for the evaporator 100 to achieve gas-liquid phase separation, and easily causing startup pulses, temperature fluctuations and startup failures. And other issues. The capillary force of the low boiling point insulating liquid is lower, which means that when the working fluid changes phase between the pores of the capillary core 120, the pressure head on the liquid side of the capillary meniscus 301 is smaller. When the heating power is high, the gas side partial pressure is higher than the liquid side partial pressure (ie, capillary head), and the capillary meniscus 301 will move toward the compensation chamber 140, forming a "bubble breaking" phenomenon. "Bubble breaking" causes the pressure and temperature of the compensation chamber 140 to increase, which affects the liquid return flow and ultimately causes the loop heat pipe to fail to start.

In formula (2): △P—bubble breaking pressure, kPa; σ—surface tension, N/m; θ—contact angle; r _eff —capillary core 120 effective pore diameter, m.

In some embodiments, the capillary core 120 has an average pore diameter less than 5 μm and is made of sintered metal powder. According to formula (2), the small-pore capillary core 120 can generate a larger capillary pressure head, effectively preventing the "bubble breaking" phenomenon, making the low boiling point and low surface tension working fluid suitable for loop heat pipes.

Specifically, the preparation steps of the capillary core 120 include:

S1. Evenly spread the metal powder with a particle size less than 20 μm into the mold after drying in the oven. Among them, the material of the metal powder can be copper, nickel or stainless steel.

S2. Mix a 50-100 μm pore-forming agent into the metal powder to increase the porosity of the metal powder sintered capillary core 120. Among them, the pore-forming agent is a salt that is easily soluble in water such as NaCl or Na ₂ CO ₃ .

S3. Use a tablet press to cold-press the metal powder in the mold, and then demould after cold-pressing to ensure that the capillary core 120 has a smaller effective aperture. Among them, the pressure of cold pressing is greater than 200MPa.

S4. Put the demolded intermediate into a nitrogen atmosphere furnace for sintering. The heating rate is 10°C/min, and the temperature is maintained for 30 to 90 minutes. The intermediate is cooled to room temperature and then taken out.

S5. Put the intermediate cooled to room temperature into deionized water for ultrasonic cleaning, and dry the cleaned intermediate to form the capillary core 120.

As shown in Figures 5 and 6, the small-pore metal powder sintered capillary core 120 prepared by the above preparation steps has a dense pore structure. According to statistics, its effective pore diameter is less than 5 μm, and most of the micropore diameters are distributed in the range of 1 to 2 μm, which can Provide a larger capillary pressure head and delay the "bubble breaking" phenomenon.

The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Under the inventive concept of the present invention, equivalent structural transformations can be made using the contents of the description and drawings of the present invention, or direct/indirect applications. Other related technical fields are included in the patent protection scope of the present invention.

Claims (9)

1. A multi-source driven high-power loop heat pipe cooling device used to dissipate heat from the chip, which is characterized by: Evaporator, the evaporator is used to absorb the heat emitted by the chip, the evaporator includes a shell and a capillary wick, the capillary wick can be filled with working medium, the shell has a sealed cavity, the capillary wick is provided in the sealed cavity, and isolates the sealed cavity into a compensation chamber and a steam channel. The steam channel is connected to a first ejector and a second ejector, and the compensation chamber is connected to the The first ejector is connected to the second ejector; A condenser, one end of the condenser is connected to the first ejector and the second ejector respectively, and the other end is connected to the compensation chamber; and A control component, the control component is connected to the second emitter and the chip respectively, and the control component can control the on/off of the second emitter according to the temperature and power of the chip; The control component includes a controller and a solenoid valve, the controller is connected to the solenoid valve and the chip respectively, the solenoid valve is connected to the second ejector, and the controller is used to control the chip according to the The temperature and power are used to control the opening or closing of the solenoid valve, and further to control the on-off of the second ejector. 2. The heat dissipation device according to claim 1, characterized in that the heat dissipation device further includes a conveying mechanism, the conveying mechanism is respectively connected with the compensation chamber, the steam channel, the first ejector, The second ejector is connected to the condenser, and the delivery mechanism is used to supply working fluid and steam in the compensation chamber, the steam channel, the first ejector, and the second ejector. Circulation flow between the ejector and the condenser. 3. The heat dissipation device according to claim 2, wherein the transport mechanism includes a first steam pipe, a second steam pipe, a first liquid pipe and a second liquid pipe, and one end of the first steam pipe is connected to The steam channel is connected, and the other end is connected to the second liquid pipe, the first ejector is provided in the first steam pipe, and one end of the second steam pipe is connected to the steam channel, The other end is connected to the second liquid pipe, the second ejector is provided in the second steam pipe, one end of the first liquid pipe is connected to the compensation chamber, and the other end is connected to the first The ejector is connected to the second ejector, an end of the second liquid pipe away from the first ejector is connected to the compensation chamber, and the condenser is arranged on the second liquid pipe. 4. The heat dissipation device according to claim 1, wherein the control component further includes a temperature sensor, the temperature sensor is respectively connected to the controller, and the temperature sensor is disposed on the chip, so The temperature sensor is used to obtain the temperature signal of the chip and transmit the temperature signal to the controller. The controller receives the temperature signal transmitted by the temperature sensor and controls the temperature signal according to the temperature signal. Open or close the solenoid valve. 5. The heat dissipation device according to claim 1, characterized in that the determination step of the controller comprises: When the temperature of the chip is greater than the first threshold and the power of the chip is greater than the second threshold, the controller turns on the second emitter; When the temperature of the chip is less than the first threshold and the power of the chip is greater than the second threshold, the controller controls the second emitter to be in an open state; When the temperature of the chip is less than the first threshold and the power of the chip is less than the second threshold, the controller controls the second emitter to be in a closed state. 6. The heat dissipation device according to claim 1, wherein the average pore diameter of the capillary core is less than 5 μm and is made of sintered metal powder. 7. The heat dissipation device according to claim 6, wherein the preparation step of the capillary core includes: The metal powder with a particle size less than 20 μm is evenly spread into the mold after drying in an oven; Mix a 50-100 μm pore-forming agent into the metal powder; The metal powder in the mold is cold-pressed and formed by a tablet press, and demolded after cold pressing, wherein the pressure of the cold pressing is greater than 200 MPa; Put the demolded intermediate into a nitrogen atmosphere furnace for sintering, with a heating rate of 10°C/min and heat preservation for 30 to 90 minutes. The intermediate is cooled to room temperature and then taken out; The intermediate after cooling to room temperature is placed in deionized water for ultrasonic cleaning, and the cleaned intermediate is dried to form the capillary core. 8. The heat dissipation device according to claim 3, wherein the first ejector includes a first steam nozzle and a first liquid nozzle, the first ejector is provided with a first mixing chamber, and the The first steam nozzle and the first liquid nozzle are both connected to the first mixing chamber, and the steam channel is connected to the first steam nozzle so that the steam in the steam channel can enter the third mixing chamber. A steam nozzle, the first liquid pipe is in communication with the first mixing chamber. 9. The heat dissipation device according to claim 8, wherein the first steam nozzle is a tapering nozzle.