Flat plate type parallel flow channel evaporator and loop thermosiphon

Abstract

The utility model belongs to the technical field of cooling and heat dissipation, and particularly relates to a flat plate type parallel flow channel evaporator and a loop thermosiphon, the evaporator is used for the loop thermosiphon, the evaporator comprises a plurality of parallel flow channels arranged in parallel, and two ends of each parallel flow channel are respectively provided with an end cover I and an end cover II; the first end cover is provided with a refrigerant inlet, the refrigerant inlet is communicated with the first containing cavity, the second end cover is provided with a refrigerant outlet, the refrigerant outlet is communicated with the second containing cavity, the surface of the evaporator is of a flat plate type structure, and the heat dissipation face of an electronic device is attached to the surface of the evaporator. The cross section area of the parallel flow channel is larger than or equal to 10 mm < 2 >, and the cross section area of the parallel flow channel is smaller than or equal to 40 mm < 2 >. The flat plate type parallel flow channel evaporator and the loop thermosiphon have the advantages of being good in heat exchange / heat dissipation performance, even in heat dissipation and easy to machine.

Description

Technical Field

[0001] The utility model belongs to the technical field of cooling and heat dissipation, and particularly relates to a flat plate type parallel flow channel evaporator and a loop heat pipe. Background Technique

[0002] As an efficient heat transfer element, the heat pipe was first proposed by General Motors in the United States. It has the advantages of high heat transfer efficiency, good isothermal property, variable heat flux density, flexible shape, wide application scenarios, no power components, stable working performance, safety and reliability, compact structure, convenient maintenance, and flexible installation. Up to now, with the mature development of science and technology and the entire industrial chain, the self-structure form of the heat pipe and its application fields are constantly expanding.

[0003] Among them, in addition to the general advantages of the heat pipe, the loop heat pipe also has significant advantages such as the ability to achieve long-distance heat transfer, flexible installation and layout, suitability for small temperature difference heat transfer, safety and reliability, and strong passivity. During the operation of the entire loop, the loop heat pipe does not require additional power such as a pump, and its driving force mainly comes from the density difference between the gas and liquid phases of the working fluid. The specific operation process can be described as follows: The refrigerant liquid with a certain degree of subcooling in the evaporation section flows in from the inlet. After absorbing the heat of the heat source, the state of the working fluid transitions from subcooled to the saturated state under the corresponding tube working pressure, and two-phase boiling occurs by further absorbing heat. The superheated steam generated after boiling rises continuously due to its small density and is transferred to the condensation section through the adiabatic steam riser under the push of a certain pressure difference between the evaporation section and the condensation section. In the condensation section, the superheated steam continuously releases heat to the outside through the tube wall, resulting in a temperature drop. And when it reaches the saturated temperature under the corresponding condensation section pressure, it condenses into a liquid. Then the saturated liquid further releases heat to the outside, thus having a certain degree of subcooling. The refrigerant with a certain degree of subcooling returns to the evaporation section inlet along the adiabatic downcomer under the action of gravity, thus completing a cycle. At present, the loop heat pipe has a wide application prospect in industrial production and life.

[0004] Currently, in the field of high-power density electronics and electrical equipment with increasingly wide applications, whether high heat flux and high-efficiency heat dissipation can be achieved has become a bottleneck for the further development of related industries. As a high heat flux heat dissipation device for passive heat transfer, the loop heat pipe only relies on gravity to quickly complete heat transfer, and at the same time has the advantages of simple structure, low operating cost, and long service life. In addition, the separated heat exchanger design of the loop heat pipe enables it to better meet the requirements of the electronics and electrical industries for high integration. Its basic structure is as Figure 1As shown in the figure: The refrigerant enters the evaporator 2' from below. After being heated, the liquid refrigerant evaporates and flows upward in the form of a two-phase mixture or superheated steam through the gas riser 4', and then enters the condenser 1'. In the condenser 1', the refrigerant condenses upon cooling and finally completely or partially fills the liquid downcomer 3' and flows back to the evaporator 2', forming a cycle.

[0005] However, in the actual application process, since the surfaces of the vast majority of electronic devices or chips are rectangular structures, the tubular evaporator design in traditional loop heat pipes cannot meet the requirement that the heat receiving surface of the heat exchanger is completely fitted with the heat dissipation surface of the electronic device, which may have an adverse impact on the temperature uniformity of the surface and inside of the electronic device. Therefore, the evaporator of the loop heat pipe must also be designed into a flat plate structure to meet the requirements of the electronic device for heat dissipation performance and temperature uniformity. For this purpose, those skilled in the art have designed a flat plate evaporative loop heat pipe, and its structure is specifically as Figure 2 shown, which includes a condenser 1', a liquid downcomer 3', an evaporator 2' and a gas riser 4' connected in sequence. Among them, the evaporator 2' is a flat plate structure with a cavity.

[0006] On this basis, since the loop heat pipe only relies on gravity circulation, its heat transfer capacity is slightly inferior to that of other pump-driven cycles. In order to enable it to meet the heat dissipation requirements of electronic devices with increasing heat flux density, it is necessary to optimize the internal structure of the heat exchanger on the basis of the flat plate design. The enhanced heat transfer effect of the microchannel can effectively improve the heat transfer capacity of the evaporator, and its compact structure design also meets the requirements of electronic devices for high integration. Therefore, people have developed a Figure 3 parallel flow loop heat pipe with microchannels 5' as shown in the figure, which includes a condenser 1', a liquid downcomer 3', an evaporator 2' and a gas riser 4' connected in sequence. Among them, the evaporator 2' is a flat plate parallel flow structure with a number of microchannels 5'. The size of the microchannels 5' is mainly reflected in its equivalent diameter, and this range is usually between 10 - 200 μm. Current relevant research has confirmed that this design helps to enhance the heat transfer effect. However, in this kind of microchannel structure, the flow resistance in the pipeline usually continues to increase with the decrease of the channel width. The relatively large flow resistance brought by too small channels will have a significant impact on the not very high driving force, thus inhibiting the cycle and heat transfer effect. Therefore, the improvement of the heat dissipation capacity is very limited.

[0007] In view of this, the present application is specifically proposed. Summary of the Utility Model

[0008] The purpose of the present utility model is to provide a flat plate parallel flow channel evaporator and a loop heat pipe for the above-mentioned existing technical problems, so as to achieve the purpose of quickly, efficiently and uniformly dissipating heat from high heat flux density electronic devices.

[0009] In view of this, the present utility model provides a flat plate type parallel flow channel evaporator applied to a loop heat pipe. The evaporator is used for the loop heat pipe and includes:

[0010] A number of parallel flow channels arranged in parallel,

[0011] At both ends of the parallel flow channels, a first end cap and a second end cap are respectively arranged. A first refrigerant accommodation cavity is arranged inside the first end cap, and a second refrigerant accommodation cavity is arranged inside the second end cap. The first accommodation cavity is respectively communicated with the inlets of each parallel flow channel, and is used for collecting and distributing the refrigerant entering the parallel flow channels. The second accommodation cavity is respectively communicated with the outlets of each parallel flow channel, and is used for collecting the refrigerant discharged from the parallel flow channels. At the same time, the first end cap and the second end cap can seal the inlets and outlets of the parallel flow channels;

[0012] A refrigerant inlet is arranged on the first end cap, and the refrigerant inlet is communicated with the first accommodation cavity. Liquid refrigerant enters the evaporator through the refrigerant inlet. A refrigerant outlet is arranged on the second end cap, and the refrigerant outlet is communicated with the second accommodation cavity. Gaseous refrigerant is discharged from the evaporator through the refrigerant outlet;

[0013] The surface of the evaporator is of a flat plate type structure, and the heat dissipation surface of the electronic device is arranged in contact with the surface of the evaporator. The cross-sectional area of the parallel flow channel ≥ 10 mm 2 , and the cross-sectional area of the parallel flow channel ≤ 40 mm 2 .

[0014] Furthermore, thermal conductive silicone grease and / or phase change material is filled in the gap between the evaporator and the heat dissipation surface of the electronic device.

[0015] Furthermore, the whole evaporator is in a cuboid shape, and the cross-section of the parallel flow channel is a rectangular channel arranged in sequence, or a trapezoidal channel arranged in a staggered manner, or a triangular channel arranged in a staggered manner.

[0016] Furthermore, fins extending along the length direction are arranged in the parallel flow channel.

[0017] Furthermore, one side of the fin is connected to the parallel flow channel, and an end enlargement structure is arranged on the other side.

[0018] Furthermore, the cross-section of the end enlargement structure is circular or elliptical.

[0019] Further, the cross-section of the parallel flow channel is a number of sequentially arranged rectangular channels. Denote the side parallel to the main heat exchange surface in the rectangular channel as the width of the rectangular channel, represented by a1; denote the side parallel to the secondary heat exchange surface as the length of the rectangular channel, represented by b1. Then, 3 mm ≤ a1 ≤ 10 mm; 3 mm ≤ b1 ≤ 14 mm, and the width a2 of the partition wall between adjacent two rectangular channels ranges from 0.1 to 0.5 mm.

[0020] Further, two fins arranged oppositely along the length direction are provided in the rectangular channel. The fins are connected to the midpoint in the width direction of the rectangular channel, and an end enlargement structure with a circular cross-section is provided at the end of the fins. Among them, the width a3 of the fins is 0.1 to 0.5 mm, the length b2 of the fins is 0.2 to 0.4 times of b1, and the diameter φ1 of the end enlargement structure is 0.5 to 1 mm.

[0021] Further, the cross-section of the parallel flow channel is a number of isosceles trapezoidal channels arranged in a staggered manner. Denote the shorter base of the isosceles trapezoid as the upper base and the longer base as the lower base. Fins are provided in the isosceles trapezoidal channel, and an end enlargement structure with an elliptical cross-section is provided at the end of the fins. The fins are located on the perpendicular bisector of the isosceles trapezoid, and one end of the fins is connected to the lower base of the isosceles trapezoid.

[0022] A loop thermosyphon, which includes: a condenser, the above-mentioned evaporator, a liquid downcomer, and a gas riser. The inlet of the condenser is connected to the outlet of the gas riser, the outlet of the condenser is connected to the inlet of the liquid downcomer, the outlet of the liquid downcomer is connected to the refrigerant inlet of the evaporator, and the refrigerant outlet of the evaporator is connected to the inlet of the gas riser.

[0023] The flat-plate parallel flow channel evaporator and the loop thermosyphon of the present utility model have the following technical effects:

[0024] First, the evaporator can be completely attached to the heat dissipation surface of the electronic device, with good heat exchange effect and uniform heat dissipation.

[0025] Second, by optimizing the cross-sectional area size and shape of the parallel flow channel, the flow state of the working medium is improved, and the heat exchange / dissipation performance is enhanced.

[0026] Third, the heat exchange area is increased through the fin structure inside the parallel channel, further improving the heat exchange / dissipation performance.

[0027] Fourth, the processing technology required for the structure of the evaporator is relatively mature, the processing cost is low, and the economic benefit is high.

[0028] In summary, the flat-plate parallel-flow channel evaporator and the loop heat pipe of the present utility model have the advantages of good heat transfer / dissipation performance, uniform heat dissipation, and easy processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of a traditional loop heat pipe;

[0030] Figure 2 is a schematic structural diagram of an existing flat-plate evaporative loop heat pipe;

[0031] Figure 3 is a schematic structural diagram of an existing micro-channel parallel-flow loop heat pipe;

[0032] Figure 4 is a schematic structural diagram of the loop heat pipe with a flat-plate parallel-flow channel evaporator of the present utility model;

[0033] Figure 5 is a schematic assembly structural diagram of the flat-plate parallel-flow channel evaporator and electrical devices of the present utility model;

[0034] Figure 6 is a three-dimensional structural diagram of the flat-plate parallel-flow channel evaporator of the present utility model;

[0035] Figure 7 is a front-view structural diagram of the flat-plate parallel-flow channel evaporator of the present utility model;

[0036] Figure 8 is Figure 7 the first sectional structural diagram in the A-A direction of

[0037] Figure 9 is Figure 7 the second sectional structural diagram in the A-A direction of

[0038] Figure 10 is Figure 7 the third sectional structural diagram in the A-A direction of

[0039] The markings in the figure are indicated as:

[0040] In Figures 1 to 3 : 1', condenser; 2', evaporator; 3', liquid downcomer; 4', gas riser; 5', micro-channel;

[0041] In Figures 4 to 10Chinese: 1. Condenser; 2. Evaporator; 201. Parallel flow channel; 202. First end cover; 203. Refrigerant inlet; 204. Second end cover; 205. Refrigerant outlet; 206. Fins; 207. End enlarged structure; 208. Main heat transfer surface; 209. Secondary heat transfer surface; 3. Liquid downcomer; 4. Gas riser; 6. Electronic device. Detailed implementation manners

[0042] The technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0043] In the description of the present application, it should be noted that the terms used herein are only for describing specific implementation manners, and are not intended to limit the exemplary embodiments according to the present application. For the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0044] It should be noted that the terms "one", "two", etc. in the description and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "one", "two", etc. are generally of the same category, and do not limit the number of objects. For example, the first object can be one or multiple. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0045] It should be noted that in the description of this application, the orientation or positional relationships indicated by the orientation terms such as "front, back, top, bottom, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationships shown in the drawings. This is only for the convenience of describing this application and simplifying the description. Without contrary explanations, these orientation terms do not indicate or imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the protection scope of this application; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0046] It should be noted that in this application, the term "comprising", "including" or any other variants thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitations, the element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of this application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, the features described with reference to certain examples may be combined in other examples.

[0047] Embodiment 1

[0048] As Figures 4 to 10 shown, a flat-plate parallel-flow channel evaporator, the evaporator 2 is used for a loop heat pipe, and it includes:

[0049] A number of parallel-flow channels 201 arranged in parallel,

[0050] End cover one 202 and end cover two 204 are respectively arranged at both ends of the parallel-flow channel 201. A refrigerant accommodation cavity one is arranged inside the end cover one 202, and a refrigerant accommodation cavity two is arranged inside the end cover two 204. The accommodation cavity one is respectively communicated with the inlets of each parallel-flow channel 201, and is used for collecting and distributing the refrigerant entering the parallel-flow channel 201. The accommodation cavity two is respectively communicated with the outlets of each parallel-flow channel 201, and is used for collecting the refrigerant discharged from the parallel-flow channel 201. At the same time, the end cover one 202 and the end cover two 204 can seal the inlets and outlets of the parallel-flow channel 201;

[0051] A refrigerant inlet 203 is provided on the first end cap 202, and the refrigerant inlet 203 communicates with the first accommodating cavity. Liquid refrigerant enters the evaporator 2 through the refrigerant inlet 203. A refrigerant outlet 205 is provided on the second end cap 204, and the refrigerant outlet 205 communicates with the second accommodating cavity. Gaseous refrigerant is discharged from the evaporator 2 through the refrigerant outlet 205;

[0052] wherein, the surface of the evaporator 2 is of a flat plate structure, so that the heat dissipation surface of the electronic device 6 can be arranged in contact with the surface of the evaporator 2 to promote heat dissipation; the cross-sectional area of the parallel flow channel 201 ≥ 10 mm 2 , and the cross-sectional area of the parallel flow channel 201 ≤ 40 mm 2 .

[0053] For the evaporator 2 of the loop thermosyphon, the refrigerant flow pattern in the parallel flow channel 201 is crucial for the heat transfer effect. Existing microchannel parallel flow evaporators mainly consist of upper and lower headers, a microchannel flat tube group connecting the two headers, and fin tapes installed between adjacent microchannel flat tubes. The interior of the microchannel flat tube is composed of multiple microchannels, which usually have various forms such as rectangular, triangular, and circular. Moreover, the width of these microchannels is usually less than 0.5 mm, generally reaching the level of a hydraulic diameter of 0.01 - 0.2 mm. Channels of this size are called microchannels. In such a narrow microchannel, due to the very small hydraulic radius of the microchannel, the transition region of the flow state is also correspondingly reduced, which may cause the refrigerant to enter the fully developed turbulent state at a very low Reynolds number. This characteristic enables microchannel condensers to have advantages in terms of heat transfer efficiency, compactness, refrigerant charge, etc. However, the improvement of the heat transfer efficiency of the microchannel parallel flow evaporator with this structure is relatively limited and can no longer meet the heat dissipation requirements of high-power density electrical equipment that is increasing day by day. In addition, since the heat pipe system does not contain a power system, the refrigerant in the evaporator mainly flows under the action of gravity and phase change driving force. For the microchannel structure, the flow resistance of the refrigerant is large and the circulation is slow, which greatly limits the improvement of the heat dissipation efficiency of the evaporator. At the same time, when the refrigerant flows and boils in such a microchannel, it is easy to generate gas plugs, further increasing the flow resistance of the refrigerant. In the improved parallel flow channel 201 of the present utility model, the refrigerant enters the evaporator 2 from the refrigerant inlet 203, and then absorbs heat through the wall of the parallel flow channel 201. During the upward movement in the parallel flow channel 201, it can successively form conversions of flow patterns such as cold boiling, bubbly flow, slug flow, churn flow, annular flow, and dispersed flow. During this flow pattern conversion process, the refrigerant can fully absorb heat through the wall and rise rapidly, not only showing a small refrigerant flow resistance but also having ideal flow pattern characteristics and good heat absorption and heat dissipation capabilities. By comparing with the existing microchannel parallel flow evaporator, when the cross-sectional area of the parallel flow channel 201 is between 10 mm 2 ~40 mm 2 , it can significantly improve the problem of a sharp increase in flow resistance caused by the too narrow channel in the existing microchannel evaporator, and at the same time optimize the refrigerant flow pattern in the channel. Under the same other conditions, the evaporator 2 of the present utility model can increase the heat dissipation capacity by more than 32% compared with the existing microchannel evaporator.

[0054] As some examples of the present utility model, when processing the evaporator 2, the processing method of the currently mature parallel flow microchannel evaporator can be referred to, and the parallel flow channel 201 can be prepared by means of metal stretching and integral forming, and the long strip end cover one 202 and the end cover two 204 are welded at the inlet and outlet of the parallel flow channel 201 to realize the collection and sealing of the refrigerant in the parallel flow channel 201, effectively avoiding the problems of heating deformation of the parallel flow channel 201 or the heating surface during welding and sealing.

[0055] Preferably, the surface of the evaporator 2 is a smooth flat plate structure. During use, the heat dissipation surface of the electronic device 6 can be closely attached to the surface of the evaporator 2 to achieve efficient and uniform heat transfer.

[0056] Furthermore, thermal conductive grease and / or phase change material are filled in the gap between the heat dissipation surface of the evaporator 2 and the electronic device 6.

[0057] Generally, there are often small gaps or uneven surfaces between the electronic device 6 and the evaporator 2, and these gaps will hinder heat conduction and reduce the heat dissipation efficiency. Thermal conductive grease has good adhesiveness and filling properties, can fill these small gaps, increase the contact area, reduce the thermal resistance, and can improve the thermal conduction efficiency between devices by filling thermal conductive grease, effectively conduct heat from the electronic device 6 to the evaporator 2, thereby accelerating the heat dissipation speed, reducing the working temperature of the electronic device 6, and improving its stability and reliability.

[0058] In addition, the fillers in the thermal conductive grease are usually metal oxides, such as alumina or boron nitride. These materials not only have good thermal conductivity, but also are not easily oxidized. Therefore, the thermal conductive grease can protect the surfaces of the electronic device 6 and the evaporator 2 from oxidation and corrosion to a certain extent and extend their service life.

[0059] In some cases, the thermal conductive grease can also play a role in sound absorption, reducing vibration and noise. For example, by improving the heat dissipation efficiency and reducing the working temperature of the electronic device 6, it can reduce the working intensity of components such as the heat dissipation fan, thereby reducing noise; or, the thermal conductive grease can act as a buffer structure between the electronic device 6 and the evaporator 2, reducing the noise generated by the oscillation and collision between the two during operation.

[0060] Moreover, filling the phase change material in the gap between the electronic device 6 and the evaporator 2 can absorb heat through the phase change process when the temperature of the electronic device 6 rises, further improving the heat dissipation efficiency. At the same time, using the phase change material can reduce the dependence of the system on auxiliary heat dissipation devices such as heat dissipation fans, thereby simplifying the heat dissipation design and reducing the equipment cost.

[0061] In some embodiments of the present invention, the phase change material can be mixed in the thermal grease for coating and use.

[0062] Preferably, the phase change material is a solid-solid phase change material.

[0063] More preferably, the weight addition ratio of the phase change material to the thermal grease is (3 - 5):10.

[0064] Preferably, the angle between the parallel flow channel 201 and the vertical direction is 0 - 18°. Within this angle range, it is not easy to form a "dry area" on the upper side wall surface of the parallel flow channel 201.

[0065] More preferably, the angle between the parallel flow channel 201 and the vertical direction is 0°, that is, the parallel flow channel 201 is arranged along the vertical direction. In this way, the gravitational force of the refrigerant can be utilized to the greatest extent to promote the circulation flow of the refrigerant.

[0066] Preferably, the evaporator 2 is integrally in a cuboid shape; correspondingly, the accommodation cavity one located in the end cover one 202 and the accommodation cavity two located in the end cover two 204 are also in a cuboid shape.

[0067] Specifically, as Figure 6 shown, a set of opposite surfaces of the evaporator 2 parallel to the heat dissipation surface of the electronic device 6 is called the main heat exchange surface 208, and a set of opposite surfaces perpendicular to the main heat exchange surface 208 is called the secondary heat exchange surface 209. The area of the main heat exchange surface 208 is more than 16 times the area of the secondary heat exchange surface 209.

[0068] Further, as Figures 8 to 10 shown, the cross-section of the parallel flow channel 201 can be a rectangular channel arranged in sequence, trapezoidal channels arranged in an alternating pattern, triangular channels arranged in an alternating pattern, etc.

[0069] As some examples of the present invention, the cross-section of the parallel flow channel 201 is a number of rectangular channels arranged in sequence. Preferably, as shown in 8, the side parallel to the main heat exchange surface 208 in the rectangular channel is denoted as the width of the rectangular channel and represented by a1; the side parallel to the secondary heat exchange surface 209 is denoted as the length of the rectangular channel and represented by b1; then, 3 mm ≤ a1 ≤ 10 mm; 3 mm ≤ b1 ≤ 14 mm, and the width a2 of the partition wall between adjacent two rectangular channels ranges from 0.1 - 0.5 mm. The rectangular channel with this size can better conduct heat exchange / heat dissipation.

[0070] Further, fins 206 extending along the length direction are arranged in the parallel flow channel 201. The fins 206 can increase the heat exchange area of the parallel flow channel 201 and promote heat exchange.

[0071] Further, one side of the fin 206 is connected to the parallel flow channel 201, and an end enlarged structure 207 is provided on the other side.

[0072] As some examples of the present invention, the cross-section of the end enlarged structure 207 is circular or elliptical. By providing the end enlarged structure 207, the flow state of the refrigerant can be improved, the heat exchange area can be further increased, and heat exchange / dissipation can be promoted.

[0073] As some examples of the present invention, as shown in FIG. 9, the cross-section of the parallel flow channel 201 is a plurality of sequentially arranged rectangular channels. Fins 206 are provided in the rectangular channels, and an end enlarged structure 207 with a circular cross-section is provided at the end of the fins 206. Among them, the width a3 of the fins 206 is 0.1-0.5 mm, the length b2 of the fins 206 is 0.2-0.4 times of b1, and the diameter φ1 of the end enlarged structure 207 is 0.5-1 mm. Preferably, two fins 206 arranged oppositely along the length direction are provided in the rectangular channel, and the fins 206 are connected to the midpoint in the width direction of the rectangular channel.

[0074] As some examples of the present invention, as shown in FIG. 10, the cross-section of the parallel flow channel 201 is a plurality of isosceles trapezoidal channels arranged in a staggered manner. The shorter base of the isosceles trapezoid is called the upper base and is represented by e1; the longer base is called the lower base and is represented by e2, then e1 = (0.3-0.4)·e2, e2 = 6-13 mm; fins 206 are provided in the isosceles trapezoidal channels, and an end enlarged structure 207 with an elliptical cross-section is provided at the end of the fins 206. The fins 206 are located on the vertical bisector of the isosceles trapezoid, and one end of the fins 206 is connected to the lower base of the isosceles trapezoid. In addition, the angle between the waist and the lower base of the isosceles trapezoid is represented by α1, and the value of α1 is 30-40°, and the height of the isosceles trapezoid, that is, the thickness of the evaporator 2 is 4-15 mm.

[0075] Further, in the parallel flow channel 201 with an isosceles trapezoidal cross-section, the width a3 of the fins 206 is 0.1-1 mm, the length b2 of the fins 206 is 0.4-0.6 times the height of the isosceles trapezoid, the short axis of the end enlarged structure 207 is 1.2-1.5 times the width a3 of the fins 206, and the long axis is 1.8-2.2 times the width a3 of the fins 206.

[0076] In addition, the present utility model also provides a loop heat pipe, and the loop heat pipe includes:

[0077] A condenser 1, the above-mentioned evaporator 2, a liquid downcomer 3, and a gas riser 4. The inlet of the condenser 1 is connected to the outlet of the gas riser 4, the outlet of the condenser 1 is connected to the inlet of the liquid downcomer 3, the outlet of the liquid downcomer 3 is connected to the refrigerant inlet 203 of the evaporator 2, and the refrigerant outlet 205 of the evaporator 2 is connected to the inlet of the gas riser 4.

[0078] The flat-plate parallel-flow channel evaporator and the loop thermosyphon according to the present utility model have the following technical effects:

[0079] First, the evaporator can be completely attached to the heat dissipation surface of the electronic device, with good heat exchange effect and uniform heat dissipation.

[0080] Second, by optimizing the cross-sectional area size and shape of the parallel-flow channel, the flow state of the working medium is improved, and the heat exchange / heat dissipation performance is enhanced.

[0081] Third, the heat exchange area is increased through the internal fin structure in the parallel channel, further improving the heat exchange / heat dissipation performance.

[0082] Fourth, the processing technology required for the structure of the evaporator is relatively mature, with low processing cost and high economic benefits.

[0083] In summary, the flat-plate parallel-flow channel evaporator and the loop thermosyphon according to the present utility model have the advantages of good heat exchange / heat dissipation performance, uniform heat dissipation, and easy processing.

[0084] The embodiments of the present application have been described above in conjunction with the accompanying drawings. Without conflict, the embodiments and the features in the embodiments in the present application can be combined with each other. The present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them belong to the protection scope of the present application.

Claims

1. A flat plate parallel flow channel evaporator, characterized in that: The evaporator (2) is used for a loop thermosyphon, and comprises: A plurality of parallel flow channels (201) arranged in parallel, An end cover 1 (202) and an end cover 2 (204) are respectively arranged at both ends of the parallel flow channel (201); a refrigerant accommodating chamber 1 is arranged in the end cover 1 (202); and a refrigerant accommodating chamber 2 is arranged in the end cover 2 (204); the accommodating chamber 1 is respectively communicated with the inlet of each parallel flow channel (201) and is used to collect and distribute the refrigerant entering the parallel flow channel (201); the accommodating chamber 2 is respectively communicated with the outlet of each parallel flow channel (201) and is used to collect the refrigerant discharged from the parallel flow channel (201); and at the same time, the end cover 1 (202) and the end cover 2 (204) can seal the inlet and outlet of the parallel flow channel (201); A refrigerant inlet (203) is provided on the first end cover (202), the refrigerant inlet (203) is communicated with the first accommodating chamber, and liquid refrigerant enters the evaporator (2) through the refrigerant inlet (203); a refrigerant outlet (205) is provided on the second end cover (204), the refrigerant outlet (205) is communicated with the second accommodating chamber, and gaseous refrigerant is discharged from the evaporator (2) through the refrigerant outlet (205); The surface of the evaporator (2) is a flat plate structure, the heat dissipation surface of the electronic device (6) is arranged in contact with the surface of the evaporator (2), and the cross-sectional area of ​​the parallel flow channel (201) is ≥ 10 mm 2 , and the cross-sectional area of ​​the parallel flow channel (201) is ≤40 mm 2 .

2. The flat plate parallel flow channel evaporator according to claim 1, characterized in that: The gap between the evaporator (2) and the heat dissipation surface of the electronic device (6) is filled with thermal conductive silicone grease and / or phase change material.

3. The flat plate parallel flow channel evaporator according to claim 1, characterized in that: The evaporator (2) is in the shape of a rectangular parallelepiped as a whole, and the cross-section of the parallel flow channels (201) is rectangular channels arranged in sequence, or trapezoidal channels arranged in a staggered manner, or triangular channels arranged in a staggered manner.

4. The flat plate parallel flow channel evaporator according to claim 3, characterized in that: A rib (206) extending along the length direction is arranged in the parallel flow channel (201).

5. The flat plate parallel flow channel evaporator according to claim 4, characterized in that: One side of the fin (206) is connected to the parallel flow channel (201), and the other side is provided with an end swelling structure (207).

6. The flat plate parallel flow channel evaporator according to claim 5, characterized in that: The cross section of the end enlarged structure (207) is circular or elliptical.

7. The flat plate parallel flow channel evaporator according to claim 3, characterized in that: The cross-section of the parallel flow channel (201) is a plurality of rectangular channels arranged in sequence, and the side of the rectangular channel parallel to the main heat exchange surface (208) is recorded as the width of the rectangular channel and is represented by a1; the side parallel to the auxiliary heat exchange surface (209) is recorded as the length of the rectangular channel and is represented by b1; then, 3mm≤a1≤10mm; 3mm≤b1≤14mm, and the width a2 of the partition wall between two adjacent rectangular channels is between 0.1 and 0.5mm.

8. The flat plate parallel flow channel evaporator according to claim 7, characterized in that: Two ribs (206) are arranged opposite to each other in the length direction in the rectangular channel, the ribs (206) are connected to the midpoint of the rectangular channel in the width direction, and an end bulging structure (207) with a circular cross-section is arranged at the end of the rib (206), wherein the width a3 of the rib (206) is 0.1-0.5 mm, and the length b2 of the rib (206) is 0.2-0.4 times b1.

9. The flat plate parallel flow channel evaporator according to claim 3, characterized in that: The cross-section of the parallel flow channel (201) is a plurality of staggered isosceles trapezoidal channels, wherein the shorter base of the isosceles trapezoid is called the upper base, and the longer base is called the lower base. A rib (206) is arranged in the isosceles trapezoidal channel, and an end bulge structure (207) with an elliptical cross-section is arranged at the end of the rib (206). The rib (206) is located on the perpendicular bisector of the isosceles trapezoid, and one end of the rib (206) is connected to the lower base of the isosceles trapezoid.

10. A loop thermosyphon, characterized in that: The loop thermosyphon comprises: A condenser (1), an evaporator (2) as claimed in any one of claims 1 to 9, a liquid downcomer (3), and a gas upcomer (4), wherein the inlet of the condenser (1) is connected to the outlet of the gas upcomer (4), the outlet of the condenser (1) is connected to the inlet of the liquid downcomer (3), the outlet of the liquid downcomer (3) is connected to the refrigerant inlet (203) of the evaporator (2), and the refrigerant outlet (205) of the evaporator (2) is connected to the inlet of the gas upcomer (4).

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