CN111328245A - Turn-back type jet flow micro-channel radiator and radiating method - Google Patents

Abstract

Disclosed are a fold-back jet micro-channel radiator and a heat dissipation method. In the fold-back jet micro-channel radiator, a micro-channel substrate is provided with a micro-channel; a jet orifice plate is laminated on the micro-channel substrate and is sealed and connected between layers, and the jet orifice plate comprises a plurality of a plurality of jet inlet holes and a plurality of return outlet holes; the distributor is stacked on the jet orifice plate and is tightly connected between layers. In the distributor, the first distribution chamber is connected to the liquid inlet pipe, and the plurality of second distribution chambers are respectively connected to the first distribution chamber and the jet inlet hole, the working medium is horizontally introduced into the second distribution chamber through the first distribution cavity and then vertically enters the jet inlet hole to impact the bottom wall of the microchannel. In the liquid return cavity, the working medium that hits the bottom wall of the microchannel is turned back into the return flow outlet hole, the working medium entering the return flow exit hole enters the first liquid return cavity through the second liquid return cavity, and the working medium entering the first liquid return cavity passes through the return flow cavity. Liquid pipe discharge.

Description

Return type jet microchannel radiator and heat dissipation method

technical field

The invention relates to the technical field of electronic device cooling, in particular to a fold-back jet microchannel radiator and a heat dissipation method.

Background technique

As the integration density continues to increase, the heat flux density of chip-level devices continues to rise. For example, high-power laser diodes and high-power electronic components consume heat flux density as high as 100W/cm ² or even higher; IGBT chips, the core components in high-speed trains and new energy vehicles The heat flux density can reach the kW level. The performance of components is more sensitive to the increase of temperature, and high temperature causes the reliability of the device to decrease, and even causes the failure of the device. The accelerated growth of component heat flux densities has brought serious technical challenges to the thermal management of electronic devices. For the problem of high heat flux density, conventional air-cooled cooling technology has been unable to meet the demand. ^In 1981, Tuckerman and Pease proposed the concept of microchannel heat sink for the high heat flux density cooling problem. Heater with high efficiency and excellent cooling performance. After the concept of micro-channel cooling was proposed, a large number of scholars have carried out research on the influence of channel shape, channel size and radiator material on the performance of micro-channel heat exchangers, and found that the heat transfer performance of micro-channels with rectangular cross-sections is better, and the depth of rectangular channels should be appropriately increased. The width ratio can increase the general conclusions such as the comprehensive heat transfer performance of the heat exchanger. At present, microchannel heat exchangers have been widely used in engineering fields such as electronics, aerospace, and locomotives. However, the traditional micro-channel heat sink still has two outstanding shortcomings: the deterioration of heat transfer along the flow direction caused by the development of the thermal boundary layer, which leads to the problem of high temperature gradient along the flow direction, and the problem of high pressure drop caused by the reduction of the channel size. These two problems have slowed the adoption of microchannels from their laboratory research. In addition, in various cooling methods, due to the strong jet impact effect and the good synergy between velocity and temperature gradient, the heat dissipation heat flux density that can be achieved by jet cooling is higher than that of traditional microchannels, and has better heat dissipation performance. , but the jet cooling has the problem of a sharp decay of the surface heat transfer coefficient outside the stagnation zone. If the advantages of jet cooling and microchannel cooling are combined, the overall performance of the heat exchanger will be greatly improved.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in the art to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provides a reentrant jet micro-channel radiator and a heat dissipation method. Through the arrangement of the inlet and outlet distributors, the uniformity of flow distribution is improved, and the pump power required by the heat exchanger is reduced. The micro-channel heat dissipation efficiently enhances heat exchange, dissipates heat evenly, and at the same time does not consume a lot of pump power, overcoming the defects of high pressure drop and uneven temperature distribution on the cooling wall surface faced by the micro-channel in the prior art.

The purpose of the present invention is to be achieved through the following technical solutions.

A fold-back jet micro-channel radiator includes,

a microchannel substrate, which is provided with microchannels;

a jet orifice plate, which is stacked on the microchannel substrate and is sealed between layers, the jet orifice plate includes a plurality of jet inlet holes and a plurality of return outlet holes;

A distributor, which is laminated on the jet orifice plate and is sealed between the layers, the distributor comprising,

The liquid inlet pipe, which is used to pump the working medium,

the first distribution chamber, which is connected to the liquid inlet pipe,

A plurality of second distribution chambers, which are respectively connected to the first distribution chamber and the jet inlet hole, the working medium is introduced into the second distribution chamber in a horizontal flow through the first distribution chamber and then vertically enters the jet inlet hole to impact all the jet inlet holes. the bottom wall of the microchannel,

a plurality of second liquid-return cavities, which are respectively connected with the return-flow outlet hole and the first liquid-return cavity;

The first liquid return cavity, the working medium entering the return flow outlet hole enters the first liquid return cavity through the second liquid return cavity,

The liquid return pipe is connected to the first liquid return cavity, and the working medium entering the first liquid return cavity is discharged through the liquid return pipe.

In the reentrant jet microchannel radiator, the first distribution cavity and/or the second distribution cavity is a wedge-shaped tapered structure along the flow direction, and the second liquid return cavity and/or the first liquid return cavity is a wedge shape progressive structure.

In the reentrant jet micro-channel heat sink, a plurality of jet inlet holes and a plurality of return outlet holes are alternately arranged.

In the reentrant jet micro-channel heat sink, the plurality of jet inlet holes and the plurality of return outlet holes are jet arrays in which incident and return flow alternate.

In the reentrant jet micro-channel radiator, the micro-channel is processed on the micro-channel substrate by machining or chemical etching, the micro-channel is a rectangular channel, and the micro-channel aspect ratio is 1- 10. The ratio of the microchannel rib width to the channel width is 0.25-2.

In the reentrant jet microchannel heat sink, the microchannels are made of copper, silicon, aluminum alloy or other materials with high thermal conductivity, and the microchannels are arranged on the microchannel substrate in parallel and at equal intervals.

In the reentrant jet micro-channel radiator, the distributor has a U-shaped structure, and the working medium includes deionized water.

In the reentrant jet micro-channel radiator, a plurality of second distribution cavities and a plurality of second liquid return cavities are arranged in a staggered manner, and the two sides are high in the middle and low in the middle.

In the reentrant jet microchannel heat sink, the diameter of the jet inlet hole is smaller than the diameter of the return flow outlet hole.

According to another aspect of the present invention, a method for dissipating heat of the reentrant jet microchannel heat sink includes the following steps:

The working medium is pumped into the first distribution chamber through the liquid inlet pipe,

The working medium flows horizontally into the second distribution cavity through the first distribution cavity and then vertically enters the jet inlet hole to impact the bottom wall of the microchannel. the backflow outlet hole,

The working medium entering the return outlet hole enters the first return cavity through the second return cavity and then is discharged through the return pipe.

Compared with the prior art, the beneficial effects of the present invention are:

散热器整体的压降将大大降低，在相同流量下，可以减小泵送工质所需的泵功。After the working fluid of the invention passes through the inlet hole of the perforated plate, it generates high kinetic energy and impacts the bottom surface of the microchannel. Due to the better synergy between the temperature gradient and the velocity, it strongly impacts the convection heat transfer belt and takes away the heat on the bottom wall of the microchannel. After the impact, the fluid flows in the microchannel to the outlet holes of the adjacent porous plate layers, and the large heat exchange area per unit volume provided by the microchannel makes the heat transfer coefficient in the cross-flow flow stronger, and the overall heat exchange performance is improved. The alternately arranged jet inlets and outlets used in the microchannel of the present invention make a single long microchannel divided into several shorter flow units, and the flow of the working medium in the microchannel is greatly reduced, and compared with that of the microchannel In a straight channel, the flow distributed on a single jet inlet is also greatly reduced, so that the flow on each flow unit is also reduced. According to the Darcy-Weisbach formula,

The overall pressure drop of the radiator will be greatly reduced, and at the same flow rate, the pump work required for pumping the working fluid can be reduced.

The invention adopts alternately arranged jet inlet holes and return holes on the microchannel, so that a single long microchannel is divided into several shorter flow units, and the temperature rise of the working medium on the smaller flow is smaller, so that the The temperature of the bottom wall of the heat exchanger is relatively uniform. In addition, because of the short flow of the jet impingement heat transfer coefficient, the attenuation of the heat transfer coefficient is small, and the surface temperature uniformity of the electronic device is also improved. The jet orifice plate and the distributor of the microchannel heat exchanger of the present invention are formed by 3D printing using polymer materials or metal materials, and the distributor and the microchannel substrate are connected by flexible sealing or formed by vacuum diffusion welding, which can ensure the reliability of the entire device. .

The above description is only an overview of the technical solution of the present invention, in order to make the technical means of the present invention clearer, to the extent that those skilled in the art can implement it according to the content of the description, and in order to make the above and other purposes of the present invention, The features and advantages can be more clearly understood, and are exemplified by specific embodiments of the present invention below.

Description of drawings

Various other advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings in the description are for the purpose of illustrating the preferred embodiments only, and are not to be considered as limiting the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort. Also, the same components are denoted by the same reference numerals throughout the drawings.

In the attached image:

Fig. 1 is the structural decomposition schematic diagram of the fold-back microchannel heat exchanger of the present invention;

Fig. 2 is the structural representation of the distributor of the present invention;

Fig. 3 is the structural representation of the jet orifice layer of the present invention;

4 is a schematic structural diagram of a microchannel substrate of the present invention;

Figure 5. Verification of tapered-expanded distribution cavity to improve flow uniformity;

6 is a schematic diagram of the flow process of the working fluid in the reentrant microchannel of the present invention;

FIG. 7 is a comparison of the flow heat transfer performance between the fold-back microchannel heat sink of the present invention and the traditional straight channel heat sink.

The present invention will be further explained below in conjunction with the accompanying drawings and embodiments.

Detailed ways

Specific embodiments of the present invention will be described in more detail below with reference to FIGS. 1 to 7 . While specific embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be more thoroughly understood, and will fully convey the scope of the present invention to those skilled in the art.

It should be noted that certain terms are used in the description and claims to refer to specific components. It should be understood by those skilled in the art that the same component may be referred to by different nouns. The description and the claims do not use the difference in terms as a way to distinguish components, but use the difference in function of the components as a criterion for distinguishing. As referred to throughout the specification and claims, "comprising" or "including" is an open-ended term and should be interpreted as "including but not limited to". Subsequent descriptions in the specification are preferred embodiments for implementing the present invention, however, the descriptions are for the purpose of general principles of the specification and are not intended to limit the scope of the present invention. The scope of protection of the present invention should be determined by the appended claims.

To facilitate the understanding of the embodiments of the present invention, the following will take specific embodiments as examples for further explanation and description in conjunction with the accompanying drawings, and each accompanying drawing does not constitute a limitation to the embodiments of the present invention.

For better understanding, as shown in Figure 1, a reentrant jet microchannel heat sink includes,

Microchannel substrate 5, which is provided with microchannels 17;

The jet orifice plate 4, which is stacked on the microchannel substrate 5 and is sealed between layers, the jet orifice plate 4 includes a plurality of jet inlet holes 10-12 and a plurality of return outlet holes 13-16;

Distributor 1, which is laminated on the jet orifice plate 4 and sealed between layers, the distributor 1 includes,

The liquid inlet pipe 2, which is used for pumping the working medium,

The first distribution cavity 6, which is connected to the liquid inlet pipe 2,

A plurality of second distribution chambers 7 are respectively connected to the first distribution chambers 6 and the jet inlet holes 10-12. The working fluid is introduced into the second distribution chambers 7 in a horizontal flow through the first distribution chambers 6 and then vertically enters the chambers. The jet inlet holes 10-12 impact the bottom wall of the microchannel 17,

A plurality of second liquid return cavities 8, which are respectively connected to the return flow outlet holes 13-16 and the first liquid return cavity 9, the working medium impacting the bottom wall of the microchannel 17 is folded back into the return flow outlet holes 13-16 ,

In the first liquid return cavity 9, the working medium entering the return flow outlet holes 13-16 enters the first liquid return cavity 9 through the second liquid return cavity 8,

The liquid return pipe 3 is connected to the first liquid return cavity 9 , and the working medium entering the first liquid return cavity 9 is discharged through the liquid return pipe 3 .

In a preferred embodiment of the reentrant jet microchannel radiator, the first distribution chamber 6 and/or the second distribution chamber 7 are wedge-shaped tapered structures along the flow direction, and the second liquid return chamber 8 and/or The first liquid return cavity 9 is a wedge-shaped gradually expanding structure.

In the preferred embodiment of the reentrant jet micro-channel heat sink, a plurality of jet inlet holes 10-12 and a plurality of return outlet holes 13-16 are alternately arranged.

In the preferred embodiment of the reentrant jet micro-channel heat sink, the plurality of jet inlet holes 10-12 and the plurality of return outlet holes 13-16 are jet arrays in which incident and return flow alternate.

In the preferred embodiment of the reentrant jet micro-channel heat sink, the micro-channel 17 is processed on the micro-channel substrate 5 by machining or chemical etching, the micro-channel 17 is a rectangular channel, and the micro-channel 17 is a rectangular channel. The channel 17 has an aspect ratio of 1-10, and the microchannel 17 has a rib width to channel width ratio of 0.25-2.

In the preferred embodiment of the reentrant jet microchannel heat sink, the microchannels 17 are made of copper, silicon, aluminum alloy or other materials with high thermal conductivity, and the microchannels 17 are arranged on the microchannel substrate 5 in parallel and at equal intervals. .

In the preferred embodiment of the reentrant jet micro-channel radiator, the distributor 1 has a U-shaped structure, and the working medium includes deionized water.

In the preferred embodiment of the fold-back jet micro-channel heat sink, the plurality of second distribution chambers 7 and the plurality of second liquid return chambers 8 are arranged in a staggered manner, and the two sides are high in the middle and low in the middle.

In the preferred embodiment of the reentrant jet micro-channel heat sink, the diameter of the jet inlet holes 10-12 is smaller than the diameter of the return flow outlet holes 13-16.

In one embodiment, the reentrant jet microchannel heat sink includes a microchannel substrate 5 etched with microchannels 17 , and a jet orifice plate 4 and a distributor 1 with low thermal conductivity are also arranged above the microchannel substrate 5 , the jet orifice plate 4 is provided with alternately arranged jet inlet holes 10-12 and return outlet holes 13-16. The distributor 1 consists of a liquid inlet pipe 2, a first distribution chamber 6, a second distribution chamber 7, and a second liquid return. The cavity 8 , the first liquid return cavity 9 and the liquid return pipe 3 are formed.

In one embodiment, the area of the microchannel 17 is equivalent to the surface area of the device to be cooled, and the base of the microchannel 17 is closely attached to the surface of the device to be cooled.

In one embodiment, the microchannels 17 are processed on the microchannel substrate 5 by machining or chemical etching technology, and are rectangular channels, which are arranged on the microchannel substrate 5 in parallel and at equal intervals.

In one embodiment, the microchannel 17 is made of copper, silicon, aluminum alloy or other materials with high thermal conductivity, the aspect ratio of the microchannel 17 is 1-10, and the ratio of the rib width to the channel width of the microchannel 17 is 0.25- 2.

In one embodiment, the jet orifice plate 4 and the distributor 1 can be formed by 3D printing from a polymer material with low thermal conductivity and high mechanical strength, or a metal with the same material as the microchannel substrate 5 is selected for machining or 3D printing. It is formed and sealed with the microchannel substrate 5 by diffusion welding.

In one embodiment, the liquid inlet pipe 2 is communicated with the first distribution chamber 6 and the second distribution chamber 7 respectively, and the second distribution chamber 7 is communicated with the jet inlet holes 10 - 12 arranged on the jet orifice plate 4 , The working medium is sent into the microchannel 17 by means of a jet, and the working medium impacts the bottom surface of the microchannel 17 to absorb the heat of the bottom wall through convection heat transfer, and carries the heat to flow out from the adjacent reflux outlet holes 13-16, and merge into the second channel. The liquid return cavity 8 flows out from the liquid return pipe 3 through the first return cavity communicated with the second return cavity.

In one embodiment, the first distribution chamber 6 and the second distribution chamber 7 are of wedge-shaped tapered design along the flow direction, the second liquid return chamber 8 and the first liquid return chamber 9 are of wedge-shaped tapered design, and the distribution chamber is of wedge-shaped tapered design. This design can effectively improve the distribution characteristics of the flow of the jet inlet holes 10-12.

In one embodiment, the numbers of the second distribution chambers 7 and the second reflow chambers depend on the precision of the machining process. If the machining process allows, the numbers of the second distribution chambers 7 and the second reflow chambers can be appropriately increased. , and correspondingly increase the number of arrays of jet inlet holes 10-12 and return outlet holes 13-16 and the number of microchannels 17 on the jet orifice plate 4 to increase the number of jet cores, enhance heat transfer and reduce pump power consumption.

In one embodiment, the jetting orifice plate 4 is arranged above the straight microchannel 17, and the arrangement direction of the jetting inlet holes 10-12 and the return outlet holes 13-16 alternately appearing on the jetting orifice plate 4 is the same as that of the microchannel substrate. The direction of the microchannel 17 on 5 is vertical, and the jet inlet hole 10-12 and the return outlet hole 13-16 are connected to the microchannel 17.

In order to further understand the present invention, in one embodiment, a fold-back microchannel jet heat exchanger is composed of a microchannel substrate 5, and a jet orifice 4 and a distributor with low thermal conductivity are sequentially arranged above the microchannel substrate 5. 1 is formed by stacking, and the layers are connected in a sealed manner. The distributor 1 is also equipped with a liquid inlet pipe 2 and a liquid return pipe 3, which are used to connect with the external working medium circulation system.

As shown in FIG. 2 , the distributor 1 is composed of a liquid inlet pipe 2 , a first distribution cavity 6 , a second distribution cavity 7 , a second liquid return cavity 8 , a first liquid return cavity 9 and a liquid return pipe 3 . The function of the distributor 1 makes the working medium pump in through the liquid inlet pipe 2, the working medium flows in through the first distribution cavity 6 and the second distribution cavity 7, and flows horizontally in the second distribution cavity 7, and the second distribution cavity 7 and the jet flow. The jet inlet holes 10-12 on the orifice plate 4 are connected, and the working fluid enters the micro-channel substrate layer 5 perpendicular to the jet orifice plate layer 4, and impacts the bottom wall of the micro-channel 17. One portion of the fluid entering in one jet inlet hole is two, along the opposite direction. The flow direction flows in the microchannel 17, absorbs the heat introduced by the bottom wall of the microchannel 17 through heat conduction, flows out from the vertical jet orifice 4 in the adjacent return outlet holes 13-16, flows into the second liquid return cavity 8, and passes through the first return flow. The liquid cavity 9 merges into the liquid return pipe 3 for discharge. The first distribution chamber 6 and the second distribution chamber 7 are of wedge-shaped tapered design, and the second return chamber 8 and the first return chamber 9 are of wedge-shaped tapered design. The uniformity in the hole, the verification of the validity of this structure is shown in Figure 5. The verification structure is a two-dimensional microchannel with a U-shaped distributor structure, and the number of channels is 7. It can be seen from Figure 5 that in In the arrangement of the U-shaped distributor, the flow uniformity in the microchannel equipped with the tapered-expanded distribution cavity is significantly improved, and the distribution effect of the seven microchannels is better than that of the straight distribution cavity.

Fig. 3 shows the jet orifice plate 4. The jet orifice plate 4 is provided with alternate jet inlet holes 10-12 and return flow outlet holes 13-16, and the jet flow inlet holes 10-12 and the return flow outlet holes 13-16 are arranged in parallel , forming an alternating jet array. The jet inlet hole 10-12 has a small diameter, and the fluid entering from the second distribution cavity 7 obtains higher kinetic energy through the narrow jet inlet hole 10-12, and the high flow velocity enhances the impact heat transfer performance. The return outlet holes 13-16 can be appropriately increased within the allowable design range (the diameter of the hole is smaller than the width of the second distribution cavity 7).

FIG. 4 shows the microchannel substrate 5. The microchannel substrate 5 is made of copper, silicon, aluminum alloy or other materials with high thermal conductivity. The microchannel 17 is processed on the microchannel substrate 5 by machining or chemical etching technology. They are parallel and equally spaced rectangular channels. In order to enhance heat transfer, the aspect ratio of the microchannels 17 is 1-10, and the ratio of the microchannel rib width to the channel width is 0.25-2. The arrangement of the rectangular microchannels 17 can effectively guide the flow against the bottom wall and sidewall surface of the microchannels 17, and the adjacent microchannels 17 are separated by ribs to weaken the influence of the adjacent jets, so that the impact cooling effect will not be affected due to the interference of the jets. .

Fig. 6 shows a schematic diagram of the working fluid flow process in the reentrant jet microchannel. From the figure, it can be seen that the jet inlet holes 10-12 and the reflux outlet holes 13-16 alternately appear on a single microchannel 17, and the working medium is in the microchannel 17. The flow in the jet is shortened to the distance between the adjacent jet inlet hole and the return flow outlet hole, such as the distance between the jet flow inlet hole 10 and the return flow outlet hole 13 . This arrangement can effectively reduce the pump power consumption of the entire radiator system, save energy and facilitate the miniaturization of the pump.

Figure 7 shows the comparison of the flow heat transfer performance of the fold-back jet microchannel radiator and the traditional straight microchannel to verify the excellent performance of the fold-back jet microchannel radiator. In this verification, the aspect ratio of the microchannel is 2. In the graph of the change of thermal resistance with pump power, the positive direction along the X-axis is the direction in which high pump power is exchanged for high heat exchange performance, and the positive direction along the Y-axis is the direction of heat exchange deterioration under low pump power consumption, At the position close to the intersection of the coordinate axes, the lower thermal resistance is achieved with low pump power consumption. It can be clearly seen from this figure that the performance of the reentrant jet microchannel heat sink is better than that of the traditional straight microchannel.

A method for dissipating heat of the fold-back jet micro-channel radiator comprises the following steps:

The working medium is pumped into the first distribution chamber 6 through the liquid inlet pipe 2,

The working medium flows horizontally into the second distribution cavity 7 through the first distribution cavity 6 and then vertically enters the jet inlet holes 10 - 12 to impact the bottom wall of the microchannel 17 and impact the bottom of the microchannel 17 The working fluid on the wall surface is folded back into the backflow outlet holes 13-16,

The working fluid entering the return outlet holes 13 - 16 enters the first liquid return cavity 9 through the second liquid return cavity 8 and then is discharged through the liquid return pipe 3 .

Industrial Applicability

The folded jet microchannel heat sink and the heat dissipation method of the present invention can be manufactured and used in the field of electronic device cooling.

The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, advantages, effects, etc. mentioned in the present application are only examples rather than limitations, and these advantages, advantages, effects, etc., are not considered to be Required for each embodiment of this application. In addition, the specific details disclosed above are only for the purpose of example and easy understanding, rather than limiting, and the above-mentioned details do not limit the application to be implemented by using the above-mentioned specific details.

The foregoing description has been presented for the purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims (10)

1. A fold-back jet microchannel radiator comprising, a microchannel substrate, which is provided with microchannels; a jet orifice plate, which is stacked on the microchannel substrate and is sealed between layers, the jet orifice plate includes a plurality of jet inlet holes and a plurality of return outlet holes; A distributor, which is laminated on the jet orifice plate and is sealed between the layers, the distributor comprising, The liquid inlet pipe, which is used to pump the working medium, the first distribution chamber, which is connected to the liquid inlet pipe, A plurality of second distribution cavities are respectively connected to the first distribution cavity and the jet inlet hole, the working fluid is introduced into the second distribution cavity in a horizontal flow through the first distribution cavity, and then vertically enters the jet inlet hole to impact all the the bottom wall of the microchannel, a plurality of second liquid-return cavities, which are respectively connected with the return-flow outlet hole and the first liquid-return cavity; The first liquid return cavity, the working medium entering the return flow outlet hole enters the first liquid return cavity through the second liquid return cavity, The liquid return pipe is connected to the first liquid return cavity, and the working medium entering the first liquid return cavity is discharged through the liquid return pipe. 2. The fold-back jet microchannel heat sink according to claim 1, wherein, preferably, the first distribution cavity and/or the second distribution cavity is a wedge-shaped tapered structure along the flow direction, and the second liquid return cavity And/or the first liquid return cavity is a wedge-shaped gradually expanding structure. 3. The fold-back jet microchannel heat sink of claim 1, wherein the plurality of jet inlet holes and the plurality of return outlet holes are alternately arranged. 4 . The foldback jet microchannel heat sink of claim 1 , wherein the plurality of jet inlet holes and the plurality of return outlet holes are in an alternating jet array of incident and return flow. 5 . 5. The reentrant jet microchannel heat sink according to claim 1, wherein the microchannel is processed on the microchannel substrate by machining or chemical etching, the microchannel is a rectangular channel, and the microchannel is a rectangular channel. The channel aspect ratio is 1-10, and the microchannel rib width to channel width ratio is 0.25-2. 6. The reentrant jet microchannel radiator according to claim 1, wherein the microchannels are made of copper, silicon, aluminum alloy or other high thermal conductivity materials, and the microchannels are arranged in parallel and at equal intervals on the microchannel substrate . 7. The reentrant jet microchannel radiator of claim 1, wherein the distributor is in a U-shaped structure, and the working medium comprises deionized water. 8 . The fold-back jet micro-channel radiator according to claim 1 , wherein the plurality of second distribution chambers and the plurality of second liquid return chambers are arranged in a staggered manner, with two sides being high in the middle and low in the middle. 9 . 9. The foldback jet microchannel heat sink of claim 1, wherein the diameter of the jet inlet hole is smaller than the diameter of the return flow outlet hole. 10. A heat dissipation method of the reentrant jet microchannel radiator according to any one of claims 1-9, comprising the following steps: The working medium is pumped into the first distribution chamber through the liquid inlet pipe, The working medium flows horizontally into the second distribution cavity through the first distribution cavity, and then vertically enters the jet inlet hole to impact the bottom wall of the microchannel, and the working medium that hits the bottom wall of the microchannel returns to enter the the backflow outlet hole, The working medium entering the return outlet hole enters the first return cavity through the second return cavity and then is discharged through the return pipe.

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