Micro-channel cold plate

Abstract

The utility model provides a micro-channel cold plate which comprises a fluid inlet, a fluid outlet and a cold plate body, the fluid inlet and the fluid outlet are both formed in the top face of the cold plate body, and a cavity allowing fluid to flow from the fluid inlet to the fluid outlet is formed in the cold plate body; the cavity comprises a throttling structure, a micro-channel fin area and an outlet buffer cavity, the micro-channel fin area is arranged between the throttling structure and the outlet buffer cavity, and the outlet buffer cavity is communicated to the fluid outlet; and the micro-channel fin area and the outlet buffer cavity are bilaterally symmetrical relative to the throttling structure. According to the micro-channel cold plate, fluid enters the micro-channel fin area in a bilateral symmetry mode through the throttling structure in the cold plate body and symmetrically flows out through the outlet buffer cavity, that is, the fluid flows basically symmetrically after entering the micro-channel area, so that the high temperature of the center of an electronic device is reduced, and the surface temperature difference of the cold plate is reduced; and the temperature uniformity is improved.

Description

Technical Field

[0001] The present application relates to the technical field of cold plates, and in particular to a microchannel cold plate. Background Art

[0002] As a type of liquid cooling technology, cold plate liquid cooling technology has the advantages of high heat dissipation efficiency, good stability and reliability, compactness and lightness, energy saving, etc. At the same time, electronic devices will not have direct contact with the coolant. At present, the technical maturity of cold plate liquid cooling technology is relatively high. Especially after combining it with microchannel enhanced heat exchange technology, the heat dissipation performance is further improved. Therefore, it is used in military radars, high-density data centers, high-performance computers, power batteries, high-power LEDs and other heat dissipation fields. It is an effective application solution to solve high-power and high-heat flow heat dissipation, improve energy efficiency, reduce refrigeration operation costs, and improve stability and reliability.

[0003] In the process of implementing the present invention, the inventors found that there are at least the following technical problems in the prior art:

[0004] At present, as the heat flux density of electronic devices gradually increases, and some electronic devices have the problem of heat concentration in the center of the device, when the existing cold plate liquid cooling device dissipates heat for electronic devices with the above problems, because the heat dissipation device and the electronic device are installed in a covering manner and the working fluid inlet of the heat dissipation device is set near its edge, it is impossible to effectively dissipate heat at the place where heat is concentrated, and the heat dissipation effect is poor, which will affect the stability and service life of the entire device. Summary of the invention

[0005] In view of this, the present application proposes a microchannel cold plate that can solve the problem of overheating concentration of electronic devices and improve the heat dissipation effect of electronic devices.

[0006] To achieve the above objectives, the present application provides a microchannel cold plate, comprising a fluid inlet, a fluid outlet and a cold plate body, wherein the fluid inlet and the fluid outlet are both arranged on the top surface of the cold plate body, and a cavity is formed inside the cold plate body for fluid to flow from the fluid inlet to the fluid outlet; the cavity comprises a throttling structure, a microchannel fin area and an outlet buffer cavity, wherein the microchannel fin area is arranged between the throttling structure and the outlet buffer cavity, and the outlet buffer cavity is connected to the fluid outlet; the microchannel fin area and the outlet buffer cavity are both symmetrical relative to the throttling structure.

[0007] In one embodiment, the fluid outlet is disposed above the throttling structure, and the microchannel fin area and the outlet buffer cavity are both symmetrical with respect to the fluid outlet.

[0008] In one embodiment, the outlet buffer chamber includes a first outlet buffer chamber and a second outlet buffer chamber, the two first outlet buffer chambers are respectively arranged on both sides of the microchannel fin area, and the second outlet buffer chamber is connected to the first outlet buffer chambers on both sides.

[0009] In one embodiment, the cavity further includes an inlet buffer cavity, which connects the fluid inlet and the throttling structure; the width of the inlet buffer cavity covers the width of the microchannel fin area; the throttling structure is located in the middle of the cold plate in the length direction, and the width of the throttling structure is consistent with the width of the inlet buffer cavity and the length is less than the length of the inlet buffer cavity.

[0010] In one embodiment, the cross-section of the throttling structure in the vertical direction is rectangular or the throttling structure is wide at the top and narrow at the bottom.

[0011] In one embodiment, the cold plate body includes a cold plate cover and a cold plate base plate, and the cold plate base plate is installed in the bottom opening of the cold plate cover; an inner partition cavity is formed inside the cold plate cover, the inlet buffer cavity is formed inside the inner partition cavity, the throttling structure is formed in the middle of the bottom of the inner partition cavity, the first outlet buffer cavity is formed between the two side walls of the inner partition cavity and the two side walls of the cold plate cover, and the second outlet buffer cavity is formed between the top surface of the inner partition cavity and the top plate of the cold plate cover.

[0012] In one embodiment, a cylinder and a column are provided on the top surface of the inner partition cavity, the cylinder connects the inlet buffer cavity and the fluid outlet, the columns are symmetrical with each other, and the cylinder and the column are abutted between the top surface of the inner partition cavity and the top plate of the cold plate cover.

[0013] In one embodiment, the microchannel fin zone is provided with multiple rows of fin groups at intervals; in each row of fin groups, a plurality of pin-fins are arranged at intervals, and microchannels are formed between adjacent pin-fins; the pin-fins in each row of fin groups are staggered with the pin-fins in the next row of fin groups in the direction of fluid flow.

[0014] In one embodiment, the pin wing is in a shape of a larger lower portion and a smaller upper portion or in a prism shape.

[0015] In one embodiment, all the bottom surfaces of the pin fins are in the same plane, and all the top surfaces of the pin fins are in the same plane and inclined to the plane where the bottom surfaces of the pin fins are located; the heights of the pin fins and the microchannels in the microchannel fin area gradually increase along the fluid flow direction.

[0016] The microchannel cold plate provided by the present application has the following beneficial effects: in the microchannel cold plate of the present application, the fluid enters the microchannel fin area symmetrically from the throttling structure in the cold plate body and flows out symmetrically through the outlet buffer cavity, that is, the fluid flows basically symmetrically after entering the microchannel area, which is beneficial to reduce the high temperature at the center of the electronic device and reduce the temperature difference on the surface of the cold plate, thereby improving the temperature uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the three-dimensional structure of a microchannel cold plate provided in one embodiment of the present application;

[0018] Figure 2 for Figure 1 Schematic diagram of the exploded structure of the microchannel cold plate in FIG.

[0019] Figure 3 for Figure 1 Microchannel cold plate Figure 1 The AA direction in the middle represents the schematic cross-sectional structure diagram of the fluid flow direction;

[0020] Figure 4 for Figure 1 Microchannel cold plate Figure 1 The AA direction in the middle shows the cross-sectional structure diagram of the cold plate layering;

[0021] Figure 5 for Figure 1 A schematic diagram of the three-dimensional structure of the microchannel cold plate with the top portion of the cold plate cover cut off;

[0022] Figure 6 for Figure 1 A schematic diagram of the three-dimensional structure of the microchannel cold plate with the upper half of the cold plate cover cut off;

[0023] Figure 7 for Figure 1 A schematic diagram of the three-dimensional structure of the cold plate cover of the microchannel cold plate from the bottom perspective;

[0024] Figure 8 for Figure 1 A schematic diagram of the three-dimensional structure of a cold plate substrate of a microchannel cold plate;

[0025] Fig. 9 for Figure 8 A magnified view of part I;

[0026] Fig.10 for Figure 8 Schematic diagram of the top view structure of the cold plate substrate.

[0027] The components in the figure are labeled as follows:

[0028] Microchannel cold plate 100;

[0029] Fluid inlet 110, fluid outlet 120, cold plate body 130;

[0030] A cold plate cover plate 131 and a cold plate base plate 132;

[0031] An inlet buffer chamber 133, a throttling structure 134, a microchannel fin area 135, a first outlet buffer chamber 136, and a second outlet buffer chamber 137;

[0032] Outlet flow layer 1301, inlet flow layer 1302, microchannel flow layer 1303;

[0033] Inner partition chamber 1311, stepped assembly groove 1312, cylinder 1313, column 1314, inclined panel 1315;

[0034] Plate body 1321 , stepped assembly edge 1322 , pin fins 1323 , and microchannel 1324 . DETAILED DESCRIPTION

[0035] Before describing the embodiments in detail, it should be understood that the present application is not limited to the detailed structure or component arrangement described below or in the drawings in the present application. The present application may be an embodiment implemented in other ways. Moreover, it should be understood that the words and terms used herein are only used for descriptive purposes and should not be interpreted restrictively. The words "including", "comprising", "having" and the like used herein are meant to include the items listed thereafter, their equivalents and other additional items. In particular, when describing "a certain element", the present application does not limit the number of the element to one, but may also include multiple elements.

[0036] In response to the problems in the prior art pointed out in the above background technology, the microchannel cold plate of the present application has the fluid in the cold plate enter from the middle and exit from both sides, and converge in the middle and flow out. Because of the heat concentration of the heat source, high temperature is generally prone to appear in the middle of the heat source. The design of the middle entrance allows the coldest fluid to preferentially cool the hottest heat source position, that is, the middle heat source, which is beneficial to reduce the junction temperature of the electronic device. In addition, compared with the design of single-side inlet and single-side outlet, the middle entrance design shortens the effective flow of the fluid, which is beneficial to reduce the temperature difference on the surface of the cold plate and improve temperature uniformity.

[0037] See also Figure 1 The microchannel cold plate 100 includes a fluid inlet 110, a fluid outlet 120 and a cold plate body 130. The fluid inlet 110 and the fluid outlet 120 are connected to the top surface of the cold plate body 130 (the cold plate cover side), and the bottom surface of the cold plate body 130 (the cold plate substrate side) is the contact surface with the electronic device with high heat flux density. In the microchannel cold plate 100, the fluid enters the cold plate 30 from the top of the cold plate 30 and then flows out from the fluid outlet 120 at the top of the cold plate 30. The fluid enters and exits from the top, which has a certain diversion effect.

[0038] Please refer to Figure 2 The cold plate body 130 includes a cold plate cover 131 and a cold plate base plate 132. The cold plate cover 131 has an opening at the bottom. The cold plate base plate 132 is embedded in the opening at the bottom of the cold plate cover 131 and is connected and positioned with the cold plate cover 131 through the assembly surface. The bottom surface of the cold plate cover 131 is flush with the bottom surface of the cold plate base plate 132. The heat source is arranged at the bottom of the cold plate body 130, that is, the bottom of the cold plate base plate 132. The fluid inlet 110 and the fluid outlet 120 are located at the top of the cold plate cover 131. The fluid outlet 120 is in the middle of the top surface of the cold plate body 130. The fluid inlet 110 is located on one side of the fluid outlet 120. The fluid enters and exits from the top, which has a certain diversion effect.

[0039] In the illustrated embodiment, on the microchannel cold plate 100, the fluid inlet 110 and the fluid outlet 120 are both cylindrical, and the diameter of the fluid outlet 120 is larger than the diameter of the fluid inlet 110. For two-phase cold plate liquid cooling, the diameter of the fluid inlet 110 is smaller than the diameter of the fluid outlet 120, which can make it easier for the refrigerant to flow out from the outlet after absorbing heat and undergoing phase change from liquid to gas, thereby reducing the risk of gas backflow.

[0040] Please refer to Figure 3, which is a schematic diagram of a vertical flow channel cross section of a microchannel cold plate 100. A cavity is formed inside the cold plate body 130 for the fluid to flow from the fluid inlet 110 to the fluid outlet 120, and includes an inlet buffer cavity 133, a throttling structure 134, a microchannel fin area 135 and an outlet buffer cavity in sequence from the fluid flow direction (as shown by the arrow in the figure). Among them, the outlet buffer cavity includes a first outlet buffer cavity 136 and a second outlet buffer cavity 137, the first outlet buffer cavity 136 is distributed on both sides of the microchannel fin area 135, and the second outlet buffer cavity 137 converges the first outlet buffer cavity 136 on both sides. The fluid in the inlet buffer cavity 133 flows horizontally, the upper end of one side of the inlet buffer cavity 133 is connected to the lower end of the fluid inlet 110, and the lower end of the other side is connected to the upper end of the throttling structure 134. The fluid in the throttling structure 134 flows from top to bottom, the upper end of the throttling structure 134 is connected to the inlet buffer cavity 133, and the lower end is connected to the microchannel fin area 135. The fluid in the microchannel fin area 135 flows transversely from the middle to both sides, and the outer sides of the microchannel fin area 135 are respectively connected to the lower ends of the first outlet buffer chamber 136. The fluid in the first outlet buffer chamber 136 flows from bottom to top, and the upper end of the first outlet buffer chamber 136 is connected to the lower end of the outer side of the second outlet buffer chamber 137. The fluid in the second outlet buffer chamber 137 flows transversely from the outer side to the middle, and the middle of the second outlet buffer chamber 137 is connected to the lower end of the fluid outlet 120. Among them, the throttling structure 134 is arranged in the middle of the cold plate body 130 in the length direction, and the microchannel fin area 135 and the first outlet buffer chamber 136 are symmetrically arranged on both sides of the throttling structure 134, and the fluids in the first outlet buffer chambers 136 on both sides converge in the second outlet buffer chamber 137.

[0041] The fluid entering the cold plate body 130 from the fluid inlet 110 from top to bottom flows horizontally toward the middle and enters the inlet buffer cavity 133. The fluid diffuses in the inlet buffer cavity 133 and then flows horizontally toward both sides after being throttled from top to bottom by the throttling structure 134 to enter the microchannel fin area 135. The fluid flowing out of the microchannel fin area 135 flows from the outside into the first outlet buffer cavity 136 from bottom to top and merges into the second outlet buffer cavity 137. In the second outlet buffer cavity 137, the fluid flows horizontally toward the middle from both sides. The fluid finally flows out from the second outlet buffer cavity 137 from bottom to top through the middle fluid outlet 120.

[0042] See also Figure 4The cavity inside the cold plate body 130 can be divided into three layers in the height direction, which are the outlet flow layer 1301, the inlet flow layer 1302 and the microchannel flow layer 1303 from top to bottom. The outlet flow layer 1301 is located at the upper part of the cold plate body 130, which is the height layer where the second outlet buffer cavity 137 is located. The inlet flow layer 1302 is located in the middle part of the cold plate body 130, which is the height layer where the inlet buffer cavity 133 is located. The microchannel flow layer 1303 is located at the lower part of the cold plate body 130, which is the height layer where the microchannel fin area 135 is located. The fluid flowing out of the microchannel flow layer 1303 flows out of the fluid outlet 120 through the outlet buffer cavity 137. The throttling structure 134 connects the inlet buffer cavity 133 of the inlet flow layer 1302 with the inlets of the two microchannel fin areas 135 of the microchannel flow layer 1303 from the middle, and the two first outlet buffer cavities 136 connect the outlets of the microchannel fin area 135 of the microchannel flow layer 1303 with the second outlet buffer cavity 137 of the outlet flow layer 1301 from both sides respectively.

[0043] Please refer to Figures 5 to 7 The cold plate cover 131 is a cavity with an opening at the bottom, and an inner partition cavity 1311 is formed inside. The edge of the bottom opening forms a stepped assembly groove 1312. An inlet buffer cavity 133 is formed inside the inner partition cavity 1311, a throttling structure 134 is formed in the middle of the bottom of the inner partition cavity 1311, a first outlet buffer cavity 136 is formed between the two side walls of the inner partition cavity 1311 and the two side walls of the cold plate cover 131, and a second outlet buffer cavity 137 is formed between the top surface of the inner partition cavity 1311 and the top plate of the cold plate cover 131.

[0044] A cylinder 1313 and a column 1314 are provided on the top surface of the inner partition chamber 1311. The cylinder 1313 is in communication with the inlet buffer chamber 133 inside the inner partition chamber 1311 and is in communication with the fluid outlet 120 on the top plate of the cold plate cover 131. The position of the column 1314 is symmetrical with the cylinder 1313, and the column 1314 abuts between the top surface of the inner partition chamber 1311 and the top plate of the cold plate cover 131. That is, the cylinder 1313 and the column 1314 are provided in the second outlet buffer chamber 137 and provide support to increase the structural strength.

[0045] Inclined panels 1315 are formed on both sides of the throttling structure 134 at the bottom of the inner partition cavity 1311 , and the inclined panels 1315 and the cold plate substrate 132 form a microchannel fin area 135 .

[0046] The vertical cross-section of the inlet buffer chamber 133 is in the shape of a rectangular parallelepiped (not limited to a rectangular parallelepiped), the width of which covers the width of the entire microchannel fin area 135 , and the lower side of which is connected to the throttling structure 134 .

[0047] The cross section of the throttling structure 134 in the horizontal direction may be a rectangle, or other shapes that are wide in the middle and narrow on both sides. In the illustrated embodiment, the cross section of the throttling structure 134 in the vertical direction is rectangular, and the width is consistent with the width of the inlet buffer cavity 133, but the length is much smaller than the length of the inlet buffer cavity 133, and is a narrow slit. The fluid flows through the throttling structure 134 to form a jet effect. In other embodiments, the cross section of the throttling structure 134 in the vertical direction may also be wide at the top and narrow at the bottom, forming a nozzle shape. In this way, the fluid enters the inlet buffer cavity 133 from the fluid inlet 110. Since the throttling structure 134 is a narrow slit, the fluid is preferentially filled horizontally, quickly filling the inlet buffer cavity 133, and then flows into the microchannel fin area 135 through the throttling structure 134, thereby improving the uniformity of fluid distribution. In addition, the narrow slit design of the throttling structure 134 forms a jet at the center position, increases the local flow velocity of the fluid, improves the heat transfer coefficient at the center position, and is conducive to enhancing heat exchange. At the same time, for two-phase cold plate liquid cooling, the narrow slit design of the throttling structure 134 increases the resistance of the gas generated by vaporization to flow back through the throttling structure 134 under the action of gravity and buoyancy, which is helpful to suppress flow instability.

[0048] The second outlet buffer cavity 137 is in communication with the fluid outlet 120, and the outlet buffer cavity 1371 and the outlet buffer cavity 1372 are connected to both sides of the microchannel fin area 135. The fluid flows from the middle of the microchannel fin area 135 to both sides and enters the first outlet buffer cavity 136 on both sides, and then flows into the second outlet buffer cavity 137, and finally flows out from the fluid outlet 120. In order to ensure the structural symmetry of the cold plate body 130, the fluid outlet 120 is designed in the middle of the cold plate body 130, and the outlet flow layer 1301 is designed with completely symmetrical cylinders 1313 and columns 1314 of the same size. In this way, the design of the fluid outlet 120 in the middle, the completely symmetrical first outlet buffer cavity 136, and the completely symmetrical cylinder 1313 and column 1314 ensure that the fluid flows completely symmetrically after entering the microchannel fin area 135 from the throttling structure 134, so that the fluid in the microchannel fin area 135 flows evenly through and out of the fluid outlet 120 through the second outlet buffer cavity 137, which is conducive to reducing the surface temperature difference of the cold plate body 130 and ensuring the temperature uniformity of the bottom surface of the cold plate body 130. For two-phase cold plate liquid cooling, the large outlet buffer cavity with upward space on both sides is not only conducive to reducing the pressure drop of the cold plate, but also conducive to easier outflow of the gas, thereby alleviating flow instability.

[0049] See also Figures 8 to 10The cold plate base plate 132 is installed in the bottom opening of the cold plate cover plate 131, and the cold plate base plate 132 includes a plate body 1321, a stepped assembly edge 1322 and pin fins 1323. The plate body 1321 is covered at the bottom of the cold plate cover plate 131, and the stepped assembly edge 1322 is formed on the circumference of the plate body 1321 and cooperates with the stepped assembly groove 1312, so that the bottom surface of the cold plate base plate 132 and the cold plate cover plate 131 are flush after assembly to form a cold plate as a whole.

[0050] The pin fin 1323 is located in the middle area of ​​the upper surface of the plate body 1321, and the top surface of the pin fin 1323 abuts against the inclined plate 1315, and a microchannel fin area 135 is formed between the plate body 1321 and the inclined plate 1315. The fins in the microchannel fin area 135 use pin fins 1323 and are arranged in staggered rows, thereby forming microchannels 1324 staggered in the direction of fluid flow. More specifically, the microchannel fin area 135 is provided with multiple rows of fin groups at intervals in the direction of fluid flow; in each row of fin groups, the pin fins 1323 are arranged at intervals, and microchannels 1324 are formed between adjacent pin fins 1323; the pin fins 1323 of each row of fin groups are staggered with the pin fins 1323 of the next row of fin groups in the direction of fluid flow. The cross section of the pin fin 1323 gradually decreases from the plate body 1321 from bottom to top, wherein the pin fin cross section of the plate body 1321 close to the cold plate base plate 132 is large, and the pin fin cross section close to the cold plate cover plate 131 is small, and from bottom to top, it is in the shape of a prism with a large lower part and a small upper part. In the illustrated embodiment, the pin fin 1323 is in the shape of a quadrangular pyramid, and the top and bottom surfaces of the pin fin 1323 are rhombus-shaped (see FIG. Fig.10 ). The microchannel fin area 135 adopts pin fins 1323, which makes the flow channels interconnected compared to the channels of straight fins, thereby improving the stability of fluid flow; the staggered pin fins 1323 strengthen the fluid turbulence, thereby enhancing the heat exchange, which is beneficial to improving the heat dissipation performance of the cold plate; for two-phase cold plate liquid cooling, the connected channels avoid the flow instability caused by pressure imbalance in the channels, and the diamond-shaped pin fins 1323 sharp corners are also beneficial to break up larger bubbles, further improving the heat exchange performance and flow stability.

[0051] The cross section of the pin fin 1323 gradually decreases from bottom to top, and the cross section of the microchannel 1324 composed of the pin fin 1323 is trapezoidal in shape. Correspondingly, the short side of the trapezoid of the cross section of the microchannel 1324 is on the cold plate substrate 132, and the long side of the trapezoid is on the side of the cold plate cover 131. The effect brought by this design is that the thickness of the pin fin 1323 gradually decreases from the cold plate substrate 132 to the cold plate cover 131, and the width of the microchannel 1324 gradually expands, so that the flow velocity at the bottom is fast and the flow velocity at the top is slow, which is conducive to strengthening the heat exchange at the contact position with the bottom surface of the cold plate substrate 132 and reducing the temperature of the cold plate. In particular, for two-phase cold plate liquid cooling, under the influence of gravity and buoyancy, the ease of bubble growth and detachment in the radial direction gradually increases, and it is easier to move upward, promoting vapor-liquid separation, which is conducive to boiling heat exchange, reducing local drying phenomenon, and improving flow stability.

[0052] The height of the pin fins 1323 and microchannels 1324 of the microchannel fin area 135 gradually increases along the direction of fluid flow. The bottom surfaces of all the pin fins 1323 are in the same plane, that is, on the upper surface of the plate body 1321, and the top surfaces of all the pin fins 1323 are in the same plane and inclined to the plane where the bottom surfaces are located. The tops of the pin fins 1323 are connected to the inclined plate 1315. From the middle position of the cold plate body 130 (at the throttling structure 134) to both sides, the height of each pin fin 1323 and microchannel 1324 increases toward the top at a certain slope, forming an inclined slope. In this way, along the direction of fluid flow, the circumferential channel cross-section gradually increases, the flow velocity in the middle position of the microchannel fin area 135 is the largest, and the flow velocity is slower the closer to the first outlet buffer chamber 136, thereby strengthening the heat exchange in the middle position, which is conducive to reducing the junction temperature of the cold plate and improving temperature uniformity. In particular, the cross-section of the circumferential channel gradually increases. For two-phase cold plate liquid cooling, the ease of bubble growth in the radial direction gradually increases, and the bubble is easy to move to the outlet side after detaching. In addition, affected by gravity and buoyancy, the bubble grows and detaches and moves upward under the influence of buoyancy. The inclined design of the top is conducive to the movement of the bubble to the outlet buffer cavity. Therefore, the inclined design of the microchannel fin area 135 further weakens the piston effect, which is conducive to eliminating bubble blockage and liquid reflux.

[0053] During operation, heat is transferred to the cold plate substrate 132 of the microchannel cold plate 100 by heat conduction. The operation process of the working medium in the microchannel cold plate 100 is as follows: the low-temperature liquid working medium enters the inlet buffer chamber 133 downward from the fluid inlet 110 under the action of the external driving force, diffuses through the inlet buffer chamber 133, and then flows downward into the microchannel fin area 135 after being throttled by the throttling structure 134. The fluid absorbs heat during the flow in the microchannel fin area 135: or, the working medium temperature rises, and the high-temperature liquid working medium flows out of the cold plate from the fluid outlet 120 through the first outlet buffer chamber 136 and the second outlet buffer chamber 137 under the pressure difference to complete the heat exchange (single-phase cold plate liquid cooling heat dissipation); or, the working medium boils and generates a large number of bubbles, becoming a two-phase flow, and the vapor-liquid mixed working medium flows out of the cold plate from the fluid outlet 120 under the pressure difference through the first outlet buffer chamber 136 and the second outlet buffer chamber 137 to complete the heat exchange (two-phase cold plate liquid cooling heat dissipation).

[0054] In summary, the present application provides a microchannel cold plate, with electronic devices with high heat flux density arranged on the bottom surface, which is versatile and can cool electronic devices with high heat flux density. It can be used for single-phase cold plate liquid cooling and heat dissipation, and can also be used for two-phase cold plate liquid cooling and heat dissipation. Compared with the prior art, the microchannel cold plate of the present application has at least the following advantages:

[0055] (1) The fluid enters the microchannel fin area from the middle throttling structure in the cold plate body and flows out symmetrically from both sides through the outlet buffer cavity. After the fluid enters the microchannel area from the throttling structure, the flow is completely symmetrical, which is beneficial to reduce the junction temperature at the center of the electronic device, reduce the temperature difference on the surface of the cold plate, and improve the temperature uniformity. Furthermore, the outlet buffer cavity includes a first outlet buffer cavity on both sides and a second outlet buffer cavity connecting the first outlet buffer cavities on both sides. For two-phase cold plate liquid cooling, the large outlet buffer cavity on both sides is not only beneficial to reduce the pressure drop of the cold plate, but also facilitates the gas to flow out more easily, thereby alleviating flow instability.

[0056] (2) A throttling structure is designed at the center of the cold plate. The throttling structure is a narrow slit. Combined with the inlet buffer cavity, the fluid is preferentially filled horizontally, quickly filling the inlet buffer cavity, and then flows into the microchannel area through the throttling structure, thereby improving the uniformity of fluid distribution. In addition, the narrow slit design of the throttling structure forms a jet at the center position, increasing the local flow velocity of the fluid, improving the heat transfer coefficient at the center position, and is conducive to enhancing heat transfer; at the same time, for two-phase cold plate liquid cooling, the narrow slit design of the throttling structure increases the resistance of the vapor generated by vaporization to flow back through the throttling structure under the action of gravity and buoyancy, which is conducive to suppressing flow instability.

[0057] (3) The fins in the microchannel area are designed with diamond-shaped pin-fins, and the pin-fins are arranged in a staggered manner, which is conducive to enhancing fluid turbulence and heat transfer. For two-phase cold plate liquid cooling, the connected channels avoid flow instability caused by pressure imbalance in the channels, and the diamond-shaped pin-fin corners are also conducive to breaking up larger bubbles, further improving heat transfer performance and flow stability.

[0058] (4) The pin-fin design is a shape with a large lower part and a small upper part, which makes the microchannel have a shape with a small lower part and a large upper part, resulting in a fast flow rate at the lower part and a slow flow rate at the upper part, which is beneficial to strengthen the heat exchange at the contact position with the cold plate substrate and reduce the temperature of the cold plate. For two-phase cold plate liquid cooling, under the influence of gravity and buoyancy, the ease of bubble growth and detachment in the radial direction gradually increases, and it is easier to move upward, promoting vapor-liquid separation, which is beneficial to boiling heat exchange, reducing local drying phenomenon, and improving flow stability.

[0059] (5) Along the direction of fluid flow, the top of the pin fin is tilted, and the height of the pin fins and microchannels on both sides increases at a certain slope toward the top, forming an inclined slope, so that the flow velocity in the middle of the microchannel area is the largest, and the flow velocity is slower as it approaches the outlet, thereby enhancing the heat exchange in the middle, which is beneficial to reducing the junction temperature of the cold plate and improving temperature uniformity. In particular, the cross-section of the circumferential channel gradually increases. For two-phase cold plate liquid cooling, the ease of bubble growth in the radial direction gradually increases, and the bubbles are easy to move to the outlet side after detaching; in addition, affected by gravity and buoyancy, the bubbles grow and detach and move upward under the influence of buoyancy. The tilted design of the top is beneficial to the movement of bubbles to the outlet. Therefore, the tilted design in the vertical direction further weakens the piston effect, which is beneficial to eliminate bubble blockage and liquid reflux.

[0060] The concepts described herein may be implemented in other forms without departing from their spirit and characteristics. The specific embodiments disclosed should be considered illustrative rather than restrictive. Therefore, the scope of this application is determined by the appended claims rather than by the preceding description. Any changes within the literal meaning and equivalent scope of the claims should fall within the scope of these claims.

Claims

1. A microchannel cold plate, characterized in that: The invention comprises a fluid inlet (110), a fluid outlet (120) and a cold plate body (130); the fluid inlet (110) and the fluid outlet (120) are both arranged on the top surface of the cold plate body (130); a cavity is formed inside the cold plate body (130) for fluid to flow from the fluid inlet (110) to the fluid outlet (120); the cavity comprises a throttling structure (134), a microchannel fin area (135) and an outlet buffer cavity; the microchannel fin area (135) is arranged between the throttling structure (134) and the outlet buffer cavity, and the outlet buffer cavity is connected to the fluid outlet (120); the microchannel fin area (135) and the outlet buffer cavity are both symmetrical with respect to the throttling structure (134).

2. The microchannel cold plate according to claim 1, characterized in that: The fluid outlet (120) is arranged above the throttling structure (134), and the microchannel fin area (135) and the outlet buffer cavity are both symmetrical with respect to the fluid outlet (120).

3. The microchannel cold plate according to claim 2, characterized in that: The outlet buffer chamber comprises a first outlet buffer chamber (136) and a second outlet buffer chamber (137), wherein the two first outlet buffer chambers (136) are respectively arranged on both sides of the microchannel fin area (135), and the second outlet buffer chamber (137) is connected to the first outlet buffer chambers (136) on both sides.

4. The microchannel cold plate according to claim 3, characterized in that: The cavity also includes an inlet buffer cavity (133), and the inlet buffer cavity (133) connects the fluid inlet (110) and the throttling structure (134); the width of the inlet buffer cavity (133) covers the width of the microchannel fin area (135); the throttling structure (134) is located in the middle of the cold plate body (130) in the length direction, and the width of the throttling structure (134) is consistent with the width of the inlet buffer cavity (133), and the length is less than the length of the inlet buffer cavity (133).

5. The microchannel cold plate according to claim 4, characterized in that: The cross section of the throttling structure (134) in the vertical direction is rectangular, or the cross section of the throttling structure (134) in the vertical direction is wide at the top and narrow at the bottom.

6. The microchannel cold plate according to claim 4, characterized in that: The cold plate body (130) comprises a cold plate cover (131) and a cold plate base plate (132), wherein the cold plate base plate (132) is installed in the bottom opening of the cold plate cover (131); an inner partition cavity (1311) is formed inside the cold plate cover (131), the inlet buffer cavity (133) is formed inside the inner partition cavity (1311), the throttling structure (134) is formed in the middle of the bottom of the inner partition cavity (1311), the first outlet buffer cavity (136) is formed between the two side walls of the inner partition cavity (1311) and the two side walls of the cold plate cover (131), and the second outlet buffer cavity (137) is formed between the top surface of the inner partition cavity (1311) and the top plate of the cold plate cover (131).

7. The microchannel cold plate according to claim 6, characterized in that: A cylinder (1313) and a column (1314) are provided on the top surface of the inner partition cavity (1311); the cylinder (1313) connects the inlet buffer cavity (133) and the fluid outlet (120); the column (1314) is symmetrical with the cylinder (1313); the cylinder (1313) and the column (1314) are abutted between the top surface of the inner partition cavity (1311) and the top plate of the cold plate cover (131).

8. The microchannel cold plate according to any one of claims 1 to 7, characterized in that: The microchannel fin area (135) is provided with multiple rows of fin groups at intervals; in each row of fin groups, a plurality of pin fins (1323) are arranged at intervals, and microchannels (1324) are formed between adjacent pin fins (1323); the pin fins (1323) in each row of fin groups are staggered with the pin fins (1323) in the next row of fin groups in the direction of fluid flow.

9. The microchannel cold plate according to claim 8, characterized in that: The pin wing (1323) is in a shape of a larger lower portion and a smaller upper portion or in a prism shape.

10. The microchannel cold plate according to claim 8, characterized in that: The bottom surfaces of all the pin fins (1323) are in the same plane, and the top surfaces of all the pin fins (1323) are in the same plane and inclined to the plane where the bottom surfaces of the pin fins (1323) are located; the heights of the pin fins (1323) and the microchannels (1324) in the microchannel fin area (135) gradually increase along the direction of fluid flow.

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