A microchannel evaporator structure that inhibits reflux

Abstract

The application discloses a micro-channel evaporator structure for inhibiting reflux, which comprises an inlet header area, a Tesla valve structure area, a parallel channel area and an outlet header area arranged in sequence along the liquid flow direction, wherein the inlet header area is configured to communicate with a fluid source outside, and the bottom of the parallel channel area is configured to contact with a heat source; a plurality of parallel channels are arranged inside the micro-channel evaporator structure, the parallel channels pass through the inlet header area and the outlet header area, and the Tesla valve structure area comprises a plurality of identical Tesla valve structures arranged on the side of the channels. The application ensures that the forward flowing fluid is hardly affected, the reverse flowing fluid is subjected to great resistance, thereby inhibiting the reverse flow of the reverse flowing fluid, and the stability of the system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high power density electronic device heat dissipation, and particularly relates to a micro-channel evaporator structure for inhibiting backflow. BACKGROUND

[0002] With the continuous development of compact electronic equipment and high-speed processors, the power of electronic components has been significantly improved. In the past few decades, the number of transistors on a chip has shown exponential growth, greatly improving its performance while also bringing greater heat production. The heat flux density of future integrated circuits will exceed 1000 W / cm2, and the local heat flux density will reach 1200-4500 W / cm2. Temperature will affect the performance, service life, and mechanical structure of power electronic devices, and failures caused by excessive temperature account for 55% of all failures, and it is estimated that the operating life of electronic products will be reduced by 50% for every 10℃ increase in operating temperature. In addition to meeting the heat dissipation needs of high power, the surface temperature of the electronic chip must not exceed 85℃ to maintain continuous operation.

[0003] The cooling methods of electronic equipment mainly include air cooling, heat pipe, spray cooling, and micro-channel cooling. Due to the differences in their own characteristics and heat dissipation capacity, different heat dissipation methods have slightly different application environments. Micro-channels have a wide range of applications in aerospace, refrigeration and air conditioning, 5G communication, fuel cells, catalytic reactions, and laser devices due to their large specific surface area, compact structure, large convective heat transfer coefficient, and ease of processing.

[0004] Pump-driven two-phase flow combined with micro-channel heat exchange technology has a wide range of applications in high heat flux density heat dissipation, but there are also flow instability problems that affect the safety and heat exchange capacity of the system. At high heat flux density, the resistance caused by the generation of bubbles will cause intermittent backflow of the fluid in the channel, and the heat exchanger will dry out due to the lack of fluid wetting, resulting in over-temperature of the electronic device.

[0005] Therefore, the technical personnel in the art are committed to developing a micro-channel evaporator structure for inhibiting backflow, which ensures that the forward-flowing fluid is almost unaffected, and the backward-flowing fluid is greatly resisted, thereby inhibiting its backward flow and improving the stability of the system. SUMMARY

[0006] In view of the above defects of the prior art, the technical problem to be solved by the present application is to provide a micro-channel evaporator structure for inhibiting backflow to solve the backflow phenomenon in the micro-channel heat exchanger. The present application is based on the Tesla valve structure to inhibit the backflow of the fluid in the channel.

[0007] In order to achieve the above-mentioned purpose, the application provides a micro-channel evaporator structure for inhibiting reflux, comprising an inlet header area, a Tesla valve structure area, a parallel channel area and an outlet header area arranged in sequence along the liquid flow direction, wherein the inlet header area is configured to communicate with a fluid source outside, and the bottom of the parallel channel area is configured to be in contact with a heat source; a plurality of parallel channels are arranged inside the micro-channel evaporator structure, the parallel channels pass through the inlet header area to the outlet header area, and the Tesla valve structure area comprises a plurality of identical Tesla valve structures arranged on the side of the channels.

[0008] Further, the plurality of identical Tesla valve structures are arranged alternately on both sides of the channels.

[0009] Further, the plurality of identical Tesla valve structures are arranged on the same side of the channels.

[0010] Further, the Tesla valve structure is a parallel Tesla valve structure composed of two or more than two Tesla valves with similar structure and different sizes.

[0011] Further, in the parallel Tesla valve structure, the structure of the small Tesla valve is located inside the structure of the large Tesla valve.

[0012] Further, the Tesla valve structure comprises an inclined pipe section and a circular arc section, the inclined pipe section is arranged obliquely on the surface of the micro-channel evaporator structure, and one end of the circular arc section is connected to the inclined pipe section and the other end is connected to the surface of the micro-channel evaporator structure.

[0013] Further, the parameters of the Tesla valve structure include the length L of the inclined pipe section, the inclination angle β, the radius R of the circular arc, the channel width d and the distance W between two Tesla valves.

[0014] Further, the direction of the parallel Tesla valve structure is perpendicular to the heating surface.

[0015] Further, the micro-channel evaporator structure comprises an upper cover plate and a channel area, the upper cover plate covers the channel area, and the Tesla valve is formed at the front end of the channel area, thereby forming the inlet header area, the Tesla valve structure area, the parallel channel area and the outlet header area.

[0016] Further, the micro-channel evaporator structure is made of metal material by 3D printing or diffusion welding, or the micro-channel evaporator structure is made of silicon-based material by anodic bonding technology.

[0017] Overall, compared with the prior art, the micro-channel evaporator structure for inhibiting reflux of fluid in the channel based on the Tesla valve structure has the following beneficial effects:

[0018] 1) The present application utilizes the single-phase conduction characteristics of the Tesla valve, which only generates greater resistance to fluid flowing in the reverse direction and smaller resistance to fluid flowing in the forward direction, compared with the inlet throttling method, thereby avoiding the introduction of a large forward pressure drop and facilitating the reduction of the required pump work.

[0019] 2) The present application adopts multiple Tesla valves in parallel to form a parallel Tesla valve structure, and a structure formed by multiple parallel Tesla valve structures in series to inhibit backflow, thereby fully utilizing the characteristics of the Tesla valve and providing a higher reverse-to-forward resistance ratio compared with conventional Tesla valve structures, and achieving a better inhibition effect.

[0020] 3) The Tesla valve structure of the present application is perpendicular to the flow direction and parallel to the heat flow input direction, so that it will not cause a sharp drop in the number of channels per heating surface due to the size of the Tesla structure, and compared with the gradually expanding channel method, it fully utilizes the space of the evaporator and improves its heat exchange capacity.

[0021] 4) The structure for inhibiting fluid backflow of the present application is not limited to a specific type of evaporator, but can be applied to various structures that may have fluid backflow, and has a wider application value.

[0022] The concept, specific structure and technical effects of the present application will be further described below with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic diagram of a micro-channel evaporator structure of a preferred embodiment of the present application;

[0024] Figure 2 is a longitudinal sectional view of Figure 1 ;

[0025] Figure 3 is a sectional view of a Tesla valve structure;

[0026] Figure 4 is a parameter diagram of the Tesla valve structure;

[0027] Figure 5 is a schematic diagram of the connection of the micro-channel evaporator structure and the heat source. DETAILED DESCRIPTION

[0028] The following describes the preferred embodiments of the present application with reference to the accompanying drawings, so as to make the technical content of the present application clearer and easier to understand. The present application can be embodied in many different forms, and the scope of protection of the present application is not limited to the embodiments described herein.

[0029] In the drawings, components with identical structures are denoted by the same reference numerals, and components with similar structures or functions are denoted by similar reference numerals. The size and thickness of each component shown in the drawings are arbitrary and are not limited by the present invention. For clarity, the thickness of components in some places in the drawings is appropriately exaggerated.

[0030] like Figure 1 and Figure 2 As shown, the present application provides a microchannel evaporator structure that suppresses backflow, including an inlet manifold area 1, a Tesla valve structure area 3, a parallel channel area 4, and an outlet manifold area 6. Along the liquid flow direction of the microchannel evaporator structure, the inlet manifold area 1, the Tesla valve structure area 3, the parallel channel area 4, and the outlet manifold area 6 are arranged in sequence. The evaporator structure is provided with a plurality of parallel channels, which are connected from the inlet manifold area 1 to the outlet manifold area 6 and are straight channels. A Tesla valve structure is provided on the side of the channel, located in the Tesla valve structure area 3. The bottom of the parallel channel area 4 is in contact with the heat source. The inlet manifold area 1 is connected to the external fluid source. During operation, the working fluid is distributed to each channel through the inlet manifold area 1. The working fluid flows along the channel in sequence through the inlet manifold area 1, the Tesla valve structure area 3, the parallel channel area 4, and the outlet manifold area 6, generating a phase change in the parallel channel area 4, thereby taking away the heat generated by the heat source. When the heat in the channel is too large, the gas generated in the channel will flow to both sides. The single-phase conduction characteristics of the Tesla valve area are utilized to suppress the backflow of the fluid in the channel, thereby ensuring the heat exchange capacity and safety of the heat exchanger.

[0031] The Tesla valve structure area 3 is arranged before the parallel channel area 4, and includes multiple Tesla valve structures 2. The one-way conduction characteristics of the Tesla valve structure 2 are used to suppress the backflow generated in the parallel channels. Since the Tesla valve structure 2 cannot achieve a complete one-way conduction function, multiple Tesla valve structures 2 are placed in the front section of each channel. At the same time, a parallel Tesla valve structure is proposed, which enhances the performance of a single Tesla valve structure 2 while making full use of the space. In some embodiments, each channel front section includes three or more Tesla valve structures 2, which are connected end to end, and can be placed alternately or on the same side according to the application scenario. For example, Figure 3 As shown, three Tesla valve structures 2 are located on either side of the channel, with two Tesla valve structures 2 placed on one side and one Tesla valve structure 2 placed on the other side, alternating between them. In some embodiments, multiple Tesla valve structures 2 can be placed on the same side. If space permits, increasing the number of Tesla valve structures 2 can improve unidirectional conduction performance. Furthermore, the Tesla valve structures 2 in front of each channel should be identical to ensure that each channel has the same conduction capacity.

[0032] like Figure 3As shown, the Tesla valve structure 2 is arranged outwardly from the surface of the micro-channel evaporator structure, including a slanted pipe section and a circular arc section, wherein the slanted pipe section is arranged obliquely to the plane in which it is located, and one end of the circular arc section is connected to the slanted pipe section and the other end is connected to the surface of the micro-channel evaporator structure. Each Tesla valve structure 2 is a parallel Tesla valve structure 2, which is composed of two or more Tesla valves of similar structure and different sizes connected in parallel. As shown in Figure 3 As shown, the arrangement of the channel in the Tesla valve is consistent with the shape of the Tesla valve, i.e. from the longitudinal section of the Tesla valve, the direction of the channel in the Tesla valve is consistent with the contour curve of the Tesla valve. In each Tesla valve structure 2, two or more parallel channels can be arranged, and the direction of each channel is consistent (i.e. these channels all have a slanted line section and a circular arc section connected in sequence), and the difference is that the size of the curve formed by each channel is different, thereby forming a ring-like pattern, i.e. a first channel is arranged near the outer side of the Tesla valve to form a Tesla valve, a second channel is arranged inside the shape formed by the first single channel to form another Tesla valve, and the small Tesla valve is located inside the large Tesla valve, and so on.

[0033] The working process of the Tesla valve structure 2 is as follows: in forward flow (solid line), in region A, only a small amount of fluid enters the circular arc section pipe due to the obtuse angle between the flow direction and the circular arc section, and in region B, the flow direction is consistent with the circular arc section pipe, so they can be merged in region B; in reverse flow (dashed line), in region B, more fluid enters the circular arc section due to the acute angle between the flow direction and the circular arc section, but in region A, the two flows almost meet head-on, resulting in large energy loss, so most of the fluid cannot flow back to the inlet header from region A.

[0034] As shown in Figure 4 The main parameters of a single parallel Tesla valve structure 2 include the length L of the slanted pipe section, the oblique angle β, the radius R of the circular arc, the channel width d, and the distance W between two Tesla valves. It is worth noting that the number of parallel Tesla valve structures 2 can be adjusted according to actual application. The direction of the parallel Tesla valve structure 2 is perpendicular to the heating surface, thereby increasing the number of channels per unit heating area.

[0035] As shown in Figure 1 The micro-channel evaporator structure can be composed of an upper cover plate 7 and a channel region 8, and the upper cover plate 7 covers the channel region 8, thereby forming an inlet header region 1, a Tesla valve structure region 3, a parallel channel region 4, and an outlet header region 6. Then the Tesla valve structure 2 is processed at the front end of the channel region 8.

[0036] The microchannel evaporator structure can be made of metal materials and processed by 3D printing technology or diffusion welding technology; it can be made of silicon-based materials and processed by anodic bonding technology.

[0037] The microchannel evaporator structure of the present invention is used as follows: Figure 5 As shown, the microchannel heat exchange structure is connected to the heating element 5 (heat source) and takes away the heat generated by the heating element 5. The heating element 5 is placed at the bottom of the parallel channel area 4, and a thermal interface material is used to reduce the contact thermal resistance therein. The external fluid enters the inlet manifold area 1 of the evaporator and is distributed to each channel. The fluid enters the parallel channel area 4 through the Tesla valve structure area 3, absorbs the heat generated by the heating element 5, and thus produces a phase change. The backflow phenomenon caused by bubble generation under high heat flux density is suppressed due to the unidirectional conduction characteristics of the Tesla valve structure area 3, so that it flows normally in the downstream direction and enters the outlet manifold area 6, preventing the local drying phenomenon caused by backflow in the microchannel evaporator and ensuring the safety and stability of the system.

[0038] The preferred embodiments of the present invention have been described in detail above. It should be understood that numerous modifications and variations based on the concepts of the present invention are possible without inventive effort by those skilled in the art. Therefore, any technical solution that can be derived by one skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A microchannel evaporator structure for suppressing backflow, characterized in that: The microchannel evaporator structure comprises an inlet header area, a Tesla valve structure area, a parallel channel area, and an outlet header area, which are sequentially arranged along the direction of liquid flow, wherein the inlet header area is configured to communicate with an external fluid source, and the bottom of the parallel channel area is configured to contact a heat source; a plurality of parallel channels are provided inside the microchannel evaporator structure, and the parallel channels directly connect from the inlet header area to the outlet header area; the Tesla valve structure area comprises a plurality of identical Tesla valve structures, which are provided on the sides of the channels; The Tesla valve structure is a parallel Tesla valve structure, which is composed of two or more Tesla valves with similar structures but different sizes connected in parallel; in the parallel Tesla valve structure, the small Tesla valve structure is located inside the large Tesla valve structure; The arrangement of the part of the channel located in the Tesla valve is consistent with the shape of the Tesla valve, that is, from the longitudinal section of the Tesla valve, the direction of the part of the channel located in the Tesla valve is consistent with the contour curve of the Tesla valve; in each Tesla valve structure, two or more parallel channels can be set, and the direction of each channel is consistent. The difference is that the size of the curve formed by each channel is different, thereby forming a ring-like figure, that is, a first channel is arranged near the outside of the Tesla valve to form a Tesla valve, and a second channel is arranged inside the shape formed by the first single channel to form another Tesla valve. The small Tesla valve is located inside the large Tesla valve, and so on.

2. The microchannel evaporator structure according to claim 1, characterized in that: The multiple identical Tesla valve structures are respectively located on both sides of the channel and are arranged alternately in sequence.

3. The microchannel evaporator structure according to claim 1, characterized in that: The plurality of identical Tesla valve structures are located on the same side of the channel.

4. The microchannel evaporator structure according to claim 1, characterized in that: The Tesla valve structure includes an inclined tube section and an arc section. The inclined tube section is obliquely arranged on the surface of the microchannel evaporator structure. One end of the arc section is connected to the inclined tube section, and the other end is connected to the surface of the microchannel evaporator structure.

5. The microchannel evaporator structure according to claim 4, characterized in that: The parameters of the Tesla valve structure include the length L of the inclined pipe section, the inclination angle β, the arc radius R, the channel width d, and the distance W between the two Tesla valves.

6. The microchannel evaporator structure according to claim 4, characterized in that: The direction of the parallel Tesla valve structure is perpendicular to the heating surface.

7. The microchannel evaporator structure according to claim 1, characterized in that: The microchannel evaporator structure includes an upper cover plate and a channel area. The upper cover plate covers the channel area and forms the Tesla valve at the front end of the channel area, thereby forming the inlet header area, the Tesla valve structure area, the parallel channel area and the outlet header area.

8. The microchannel evaporator structure according to claim 1, characterized in that: The microchannel evaporator structure is made of metal material through 3D printing or diffusion welding, or the microchannel evaporator structure is made of silicon-based material through anodic bonding technology.

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