Phase change cold plate and method of operation thereof

Abstract

The application belongs to the technical field of heat dissipation, and discloses a phase change cold plate and a working method thereof. The phase change cold plate comprises a heat exchange body, a heat exchange cavity is arranged in the heat exchange body, and an outlet and an inlet are arranged at the upper and lower ends of the heat exchange cavity respectively. A sparse tooth section, a gas-liquid separation section and a dense tooth section are sequentially arranged in the heat exchange cavity from bottom to top, heat exchange bodies are arranged in each section, and a spacing is left between the heat exchange bodies and the side walls of the heat exchange cavity. The heat exchange bodies are all straight fin heat exchange bodies, and the straight fins in the sparse tooth section and the dense tooth section are vertically arranged. The spacing of the straight fins in the sparse tooth section, the gas-liquid separation section and the dense tooth section increases sequentially. The straight fins in the gas-liquid separation section are arranged obliquely, the straight fins in the gas-liquid separation section can guide the gas phase formed in the sparse tooth section and the gas-liquid separation section to flow to the side wall direction of the heat exchange cavity, and can guide the liquid phase in the gas-liquid separation section to flow to the heat exchange bodies in the dense tooth section. The heat exchange fins in the phase change cold plate are reasonably designed, and uniform heat exchange of the phase change cold plate can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of heat dissipation and relates to a phase change cold plate and a working method thereof. Background Art

[0002] Traditional cold plates, typically manufactured using a fin welding process, have a simple structure and are only suitable for conventional media. Existing cold plate structures do not consider the operating conditions of phase-change media. Consequently, their internal fins are evenly distributed, resulting in stable heat transfer performance when the working fluid remains unchanged. However, when a phase-change medium is introduced, these plates are unable to adapt to its operating conditions. After the liquid absorbs heat and vaporizes near the inlet, the amount of liquid participating in the phase-change heat transfer near the outlet decreases significantly, and the gas is difficult to expel quickly. This results in a large temperature difference between the front and rear sections of the cold plate, making it susceptible to heat loss. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a phase change cold plate and a working method thereof. The present invention can achieve uniform heat exchange of the phase change cold plate by rationally designing the heat exchange fins in the phase change cold plate.

[0004] The technical solution adopted in the present invention is as follows:

[0005] A phase change cold plate comprises a heat exchange body, a heat exchange cavity is provided in the heat exchange body, an outlet is provided at the upper end of the heat exchange cavity, and an inlet is provided at the lower end of the heat exchange cavity, wherein the outlet and the inlet are both connected to the heat exchange cavity;

[0006] The heat exchange chamber is provided with a sparse tooth section, a gas-liquid separation section, and a dense tooth section from bottom to top, and each of the sparse tooth section, the gas-liquid separation section, and the dense tooth section is provided with a heat exchange body; a horizontal spacing is left between each heat exchange body and the side wall of the heat exchange chamber, and the spacing between the heat exchange body in the dense tooth section and the side wall of the heat exchange chamber is larger than the spacing between the heat exchange body in the sparse tooth section and the gas-liquid separation section; the heat exchange bodies are all straight fin heat exchange bodies, wherein the length direction of the straight fins in the sparse tooth section and the dense tooth section is arranged vertically; the spacing between the straight fins in the sparse tooth section is larger than the spacing between the straight fins in the dense tooth section, and the spacing between the straight fins in the gas-liquid separation section is larger than the spacing between the straight fins in the dense tooth section and smaller than the spacing between the straight fins in the sparse tooth section;

[0007] The straight fins in the gas-liquid separation section are arranged at an angle. The straight fins in the gas-liquid separation section can guide the gas phase formed in the sparse tooth section and the gas-liquid separation section toward the side wall of the heat exchange cavity, and guide the liquid phase in the gas-liquid separation section to the heat exchange body of the dense tooth section.

[0008] Preferably, the outlet and the inlet are vertically opposite, and the heat exchange cavity, the sparse tooth section, the gas-liquid separation section, the dense tooth section and each heat exchange body are symmetrical about the central axis of the outlet and the inlet;

[0009] The straight fins on the same side of the inlet central axis in the gas-liquid separation section are parallel to each other, and channels for liquid cooling medium to flow are reserved between the straight fins on both sides of the inlet central axis in the gas-liquid separation section and the inlet central axis.

[0010] Preferably, from bottom to top, the straight fins of the heat exchanger in the gas-liquid separation section are divided into several layers, and each layer is provided with several straight fins;

[0011] On one side of the inlet center axis: in the same layer, for two adjacent straight fins, the projections of the upper end of the previous straight fin and the lower end of the next straight fin on the horizontal plane overlap, and for the straight fin far away from the inlet center axis, a preset distance is left between the upper end of the straight fin and the side wall of the heat exchange chamber; for two adjacent layers, a straight fin is provided on the upper layer above the junction of the two adjacent straight fins of the lower layer, and a specific area of ​​the straight fin is opposite to the junction position of the two adjacent straight fins of the lower layer, and the specific area is an area one-third to two-thirds away from the edge of the straight fin; for the uppermost layer, the upper end of the straight fin close to the inlet center axis is at least aligned with the lower end of the outermost straight fin of the dense tooth section, or exceeds the lower end of the outermost straight fin of the dense tooth section and extends to the side wall of the heat exchange chamber.

[0012] Preferably, at least two straight fins are provided in each layer, and the projected length of each straight fin on the horizontal plane is not less than the spacing between the straight fins in the sparse tooth section.

[0013] Preferably, the inclination angle of the straight fins of the heat exchanger in the gas-liquid separation section is 43°-47°.

[0014] Preferably, a preset distance is left between the inlet and the sparse tooth section, and the preset distance enables the fluid to fully develop and flow;

[0015] There is a preset distance between the outlet and the dense-tooth section, which enables the fluid to fully develop and flow.

[0016] Preferably, the cross-sectional shape of the portion of the heat exchange chamber between the inlet and the sparse tooth section is set to be an isosceles trapezoid, wherein the inlet is set in the middle of the upper base of the isosceles trapezoid;

[0017] The cross-sectional shape of the portion of the heat exchange chamber located between the outlet and the dense-tooth section is set to be an isosceles trapezoid, wherein the outlet is set in the middle of the upper base of the isosceles trapezoid.

[0018] Preferably, the heat exchange areas on the side of the heat exchange body and the heat source surface in the sparse tooth section, the gas-liquid separation section and the dense tooth section are the same, and the flow channel lengths occupied are the same.

[0019] Preferably, the heat exchange body includes a flow channel plate and an upper cover, the heat exchange cavity is opened inward from one side surface of the flow channel plate, the outlet and the inlet are both opened on the flow channel plate, the heat exchange bodies in the sparse tooth section, the gas-liquid separation section and the dense tooth section are all arranged at the bottom of the heat exchange cavity, and the upper cover is fixedly connected to the flow channel plate and seals the open end of the heat exchange cavity;

[0020] For all heat exchangers, along the width direction of the straight fins, one side of the straight fins is located on the bottom surface of the heat exchange cavity, and the other side of the straight fins is against and sealed against the surface of the upper cover.

[0021] The working method of the phase change cold plate of the present invention includes the following steps:

[0022] The fully liquid cooling medium enters the heat exchange chamber from the inlet. As the cooling medium flows, part of the cooling medium absorbs heat and turns into gas.

[0023] After the cooling medium flows through the sparse tooth section, the inclined straight fins in the gas-liquid separation section guide the gas in the cooling medium toward the side wall of the heat exchange chamber. The gas guided toward the side wall of the heat exchange chamber rises along the channel between the heat exchange body and the side wall of the heat exchange chamber in the gas-liquid separation section, and along the channel between the heat exchange body and the side wall of the heat exchange chamber in the dense tooth section, and is discharged from the outlet.

[0024] When the cooling medium flows through the heat exchanger in the gas-liquid separation section, the inclined straight fins in the gas-liquid separation section guide the liquid cooling medium into the heat exchanger in the dense tooth section.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In the phase change cold plate provided by the present invention, the spacing between the straight fins in the sparse tooth section, the gas-liquid separation section and the dense tooth section is gradually reduced. Therefore, the front (i.e., the inlet end) and rear (i.e., the outlet end) sections of the phase change cold plate of the present invention are divided into different fin areas for heat exchange, so that the heat exchange amount of the cooling medium in the front and rear sections of the phase change cold plate is the same; in the present invention, a spacing is left between the heat exchange body and the heat exchange cavity in the horizontal direction, and the spacing can serve as a channel for the gas-phase cooling medium to rise; at the same time, the straight fins in the gas-liquid separation section are inclined, and the straight fins in the gas-liquid separation section can guide the gas phase formed in the sparse tooth section and the gas-liquid separation section toward the side wall of the heat exchange cavity, and the gas-liquid separation section The liquid phase in the heat exchanger is guided to the heat exchanger of the dense tooth section. Therefore, the gas-liquid separation section can make the gas-phase cooling medium flow to the edge of the heat exchanger (that is, flow to the heat exchanger and the heat exchange cavity), and the liquid-phase cooling medium flow to the center, thereby realizing gas-liquid diversion and improving the heat exchange efficiency and gas discharge rate of the dense flow channel in the rear section. In addition, in order to adapt to the increasing amount of gas-phase cooling medium generated, the present invention sets the distance between the heat exchanger of the dense tooth section and the side wall of the heat exchange cavity to be greater than the distance between the heat exchanger of the sparse tooth section and the side wall of the heat exchange cavity as well as the gas-liquid separation section. This ensures that the gas-phase cooling medium can be discharged in time, which is conducive to achieving uniform heat exchange of the phase change cold plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a front view of the phase change cold plate structure in an embodiment of the present invention;

[0028] Figure 2 This is a front view of a phase change cold plate in an embodiment of the present invention with local dimension markings (unit: mm);

[0029] Figure 3 This is an axonometric diagram of the phase change cold plate structure in an embodiment of the present invention;

[0030] Figure 4 This is an overall appearance diagram of the phase change cold plate structure in an embodiment of the present invention;

[0031] Figure 5 A partial schematic diagram of a phase change cold plate structure in an embodiment of the present invention;

[0032] Figure 6 Flow trace diagram of the cooling medium in the embodiment of the present invention, wherein (a) is the gas flow trace diagram, and (b) is the liquid flow trace diagram.

[0033] In the figure, 1-inlet, 2-outlet, 3-sparse tooth section, 4-gas-liquid separation section, 5-dense tooth section, 6-installation positioning hole, 7-upper cover, 8-flow channel plate, 9-heat exchange chamber, 9-1-side wall of heat exchange chamber, 10-straight fin No. 1, 11-straight fin No. 2, 12-straight fin No. 3, 13-straight fin No. 4, 14-straight fin No. 5, 15-straight fin No. 6, 16-straight fin No. 7, 17-straight fin No. 8, 18-straight fin No. 9, 19-straight fin No. 10. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0035] Reference Figure 1-Figure 5The phase change cold plate of the present invention includes a heat exchange body, in which a heat exchange cavity 9 is provided, an outlet 2 is opened on the heat exchange body at the upper end of the heat exchange cavity 9, and an inlet 1 is opened on the heat exchange body at the lower end of the heat exchange cavity 9, and the outlet 2 and the inlet 1 are both connected to the heat exchange cavity 9; a sparse tooth section 3, a gas-liquid separation section 4 and a dense tooth section 5 are sequentially provided in the heat exchange cavity 9 from bottom to top, and a heat exchange body is provided in the sparse tooth section 3, the gas-liquid separation section 4 and the dense tooth section 5; a spacing is left between each heat exchange body and the side wall of the heat exchange cavity 9 in the horizontal direction, and the spacing serves as a flow channel for the gas-phase cooling medium generated in each section (including the sparse tooth section 3, the gas-liquid separation section 4 and the dense tooth section 5), and the spacing between the heat exchange body of the dense tooth section 5 and the side wall of the heat exchange cavity 9 is greater than the spacing between the heat exchange body of the sparse tooth section 3 and the gas-liquid separation section 4 and the heat exchange cavity 9. The spacing between the side walls can adapt to the accumulation of continuously generated gaseous cooling medium by gradually increasing the spacing, so that the gaseous cooling medium in the heat exchange chamber 9 can be quickly and smoothly discharged from the outlet 2, thereby ensuring the heat exchange effect; the heat exchange body adopts a straight fin type heat exchange body, wherein the length direction of the straight fins in the sparse tooth section 3 and the dense tooth section 5 is arranged along the vertical direction; the spacing of the straight fins in the sparse tooth section 3 is greater than the spacing of the straight fins in the dense tooth section 5, and the spacing of the straight fins in the gas-liquid separation section 4 is greater than the spacing of the straight fins in the dense tooth section 5 and less than the spacing of the straight fins in the sparse tooth section 3; the straight fins in the gas-liquid separation section 4 are inclined, and the straight fins in the gas-liquid separation section 4 can guide the gas phase formed in the sparse tooth section 3 and the gas-liquid separation section 4 toward the side wall of the heat exchange chamber 9 (see Figure 6 (a) in the figure), and the liquid phase in the gas-liquid separation section 4 is directed to the heat exchange body of the dense tooth section 5 (see Figure 6 (b) in the figure).

[0036] The heat exchange performance of the phase-change cold plate described above is illustrated by the following: the cooling fluid vaporizes in the heat-absorbing portion of the coarse-tooth segment 3, the gas-liquid mixture is diverted in the gas-liquid separation segment 4, and the gaseous cooling fluid flows into the gas flow channels on both sides of the heat exchange cavity (i.e., the horizontal spacing between each heat exchange element and the sidewalls of the heat exchange cavity 9) for discharge, while the liquid phase flows into the dense-tooth segment 5 for continued heat exchange. The internal flow channel structure (heat exchange elements in the coarse-tooth segment 3, gas-liquid separation segment 4, and dense-tooth segment 5) adjusts the fin spacing and fin size according to the gas-liquid ratio, ensuring that the same heat exchange efficiency is maintained throughout the flow of fluids with different gas-liquid ratios within the cold plate.

[0037] See also Figure 6 Figure (a) and (b) in the figure, combined with Figure 1-Figure 5 The working method of the phase change cold plate of the present invention includes the following steps:

[0038] The fully liquid cooling medium enters the heat exchange chamber 9 from the inlet 1. As the cooling medium flows, part of the cooling medium absorbs heat and turns into gas.

[0039] After the cooling medium flows through the sparse-tooth section 3, the inclined straight fins in the gas-liquid separation section 4 guide the gas in the cooling medium toward the side wall of the heat exchange chamber 9. The gas guided toward the side wall of the heat exchange chamber 9 rises along the channel between the heat exchange element in the gas-liquid separation section 4 and the side wall of the heat exchange chamber 9, and along the channel between the heat exchange element in the dense-tooth section 5 and the side wall of the heat exchange chamber 9, and is discharged from the outlet 2.

[0040] When the cooling medium flows through the heat exchanger in the gas-liquid separation section 4 , the inclined straight fins in the gas-liquid separation section 4 guide the liquid cooling medium into the heat exchanger in the dense-tooth section 5 .

[0041] As a preferred embodiment of the present invention, based on the above-mentioned embodiment of the present invention, see Figure 1 , the outlet 2 and the inlet 1 are vertically opposite (i.e., the central axes of the inlet 1 and the outlet 2 are coaxial), the heat exchange cavity 9, the sparse tooth section 3, the gas-liquid separation section 4, the dense tooth section 5 and each heat exchange body are symmetrical about the central axis of the outlet 2 and the inlet 1; Figure 6 Take Figure (b) in the example and combine Figure 1 The straight fins on the same side of the central axis of the inlet 1 in the gas-liquid separation section 4 are parallel to each other, and a channel for liquid cooling medium to flow is left between the straight fins on both sides of the central axis of the inlet 1 in the gas-liquid separation section 4 and the central axis of the inlet 1. Figure 5 There is a distance between the left and right rows of inclined straight fins, which is mainly used for the circulation channel of the liquid cooling medium. The straight fins located on both sides of the central axis of the inlet 1 in the gas-liquid separation section 4 can guide and gather the liquid cooling medium toward the central axis of the inlet 1, and finally be guided by the inclined straight fins in the gas-liquid separation section 4 to the heat exchange element of the dense tooth section 5 for efficient heat exchange.

[0042] As a preferred embodiment of the present invention, based on the above embodiment of the present invention, the straight fins of the heat exchanger in the gas-liquid separation section 4 are divided into several layers from bottom to top, and each layer is provided with several straight fins; Figure 5 For example, the straight fin No. 10, the straight fin No. 2, the straight fin No. 11, the straight fin No. 6, the straight fin No. 15, and the straight fin No. 7, the straight fin No. 16 are on the same layer, the straight fin No. 3, the straight fin No. 12, and the straight fin No. 8, the straight fin No. 17 are on the same layer, the straight fin No. 4, the straight fin No. 13, and the straight fin No. 9, the straight fin No. 18 are on the same layer, and the straight fin No. 5, the straight fin No. 14, and the straight fin No. 10, the straight fin No. 19 are on the same layer;

[0043] At the center axis of inlet 1 (i.e. Figure 5 The entire structure shown in the figure has a symmetry axis on one side (with Figure 5The left or right side shown is acceptable): In the same layer, for two adjacent straight fins, the projections of the upper end of the previous straight fin and the lower end of the next straight fin on the horizontal plane overlap (taking the straight fin No. 10 and the straight fin No. 2 11 as an example, the projections of the upper end of the straight fin No. 10 and the lower end of the straight fin No. 2 11 on the horizontal plane overlap). This can ensure that the cooling medium contacts the straight fins and absorbs heat, and prevent the gaseous cooling medium from moving a long path on the side close to the central axis of the inlet 1 (if they do not overlap, the distance between the straight fin No. 10 and the straight fin No. 2 11 is greater than the distance between the straight fin No. 10 and the straight fin No. 2 11). The gaseous cooling medium will continue to rise to the third straight fin 12 for heat exchange, which reduces the heat exchange efficiency), improve the cooling efficiency, and on the other hand, can increase the speed of the gaseous cooling medium moving toward the side wall of the heat exchange cavity 9, so that the gaseous cooling medium can be quickly discharged, improving the cooling effect and the uniformity of the temperature of the entire cold plate. For the straight fins away from the central axis of the inlet 1 (i.e., the straight fins close to the side wall of the heat exchange cavity 9, such as the second straight fin 11 and the seventh straight fin 16), a preset distance is left between the upper end of the straight fin (such as the second straight fin 11) and the side wall of the heat exchange cavity 9 (see Figure 2 ), this distance can provide a channel for the gaseous cooling medium to flow upward, which is conducive to the rapid discharge of the gaseous cooling medium; for two adjacent layers (such as Figure 5 In the first layer (including the first straight fin 10, the second straight fin 11, the sixth straight fin 15 and the seventh straight fin 16) and the second layer (including the third straight fin 12 and the eighth straight fin 17) from bottom to top, a straight fin (such as the third straight fin 12) is provided above the intersection of the two adjacent straight fins (such as the first straight fin 10 and the second straight fin 11) in the lower layer, and a specific area of ​​the straight fin (such as the third straight fin 12) is aligned with the two adjacent straight fins (such as the first straight fin 10 and the second straight fin 11) in the lower layer. The intersection positions of the sheet 10 and the second straight fin 11 are opposite to each other up and down, and the specific area is the area from one-third (such as point A) to two-thirds (such as point B) from the edge of the straight fin; for the uppermost layer, the upper end of the straight fin close to the central axis of the inlet 1 (such as the fifth straight fin 14) is at least aligned with the lower end of the outermost straight fin of the dense-tooth segment 5, or exceeds (exceeds to the right, and for the tenth straight fin 19, exceeds to the left) the lower end of the outermost straight fin of the dense-tooth segment 5 and extends toward the side wall of the heat exchange chamber 9.

[0044] The gas-liquid separation section 4 of the above-mentioned structure of the present invention can effectively realize the gas-liquid separation of the cooling medium (the gas-liquid separation mentioned in the present invention is not a complete separation in an absolute sense, but actually refers to the ability to separate most of the gaseous cooling medium and the liquid cooling medium and rise along different paths, thereby improving the discharge efficiency of the gaseous cooling medium).

[0045] As a preferred embodiment of the present invention, see Figure 5, so at least two straight fins are set in each layer. The specific number of fins is related to the size of the heat exchange cavity 9 and the size of the heat exchange body in the sparse tooth section 3, the gas-liquid separation section 4 and the dense tooth section 5. Figure 5 As the number of straight fins in each layer increases, the number of straight fins in each layer will increase accordingly. The setting form of straight fins in each layer can refer to Figure 5 The structure of the bottom layer is expanded in the left and right directions, but the requirements for each layer are the same as the requirements for the arrangement of the straight fins in the gas-liquid separation section 4. The projected length of each straight fin on the horizontal plane is not less than the spacing between the straight fins in the sparse tooth section 3, which can ensure the heat exchange efficiency and gas-liquid separation efficiency.

[0046] In a preferred embodiment of the present invention, if the tilt angle of the straight fins in the gas-liquid separation section 4 is too large, the velocity of the liquid flowing down the tilted straight fins will be too high, creating vortices with the incoming liquid from the sparse-tooth section, hindering the liquid from flowing into the dense-tooth section 5. If the tilt angle is too small, the upward resistance of the gas will increase, hindering the gas from flowing to the edge channels. Testing has shown that the tilt angle of the straight fins in the heat exchanger of the gas-liquid separation section 4 of the present invention is 45°±2°.

[0047] As a preferred embodiment of the present invention, Figure 1 As shown, a preset distance is left between the inlet 1 and the sparse-tooth segment 3, and the preset distance enables the fluid to fully develop and flow; a preset distance is left between the outlet 2 and the dense-tooth segment 5, and the preset distance enables the fluid to fully develop and flow.

[0048] As a preferred embodiment of the above-mentioned solution of the present invention, Figure 1 As shown, the cross-sectional shape of the portion of the heat exchange chamber 9 located between the inlet 1 and the sparse tooth segment 3 is set to an isosceles trapezoid, wherein the inlet 1 is set in the middle of the upper base of the isosceles trapezoid; the cross-sectional shape of the portion of the heat exchange chamber 9 located between the outlet 2 and the dense tooth segment 5 is set to an isosceles trapezoid, wherein the outlet 2 is set in the middle of the upper base of the isosceles trapezoid.

[0049] As a preferred embodiment of the above scheme of the present invention, the heat exchange areas on the heat exchanger side and the heat source surface in the sparse tooth section 3, the gas-liquid separation section 4 and the dense tooth section 5 are the same and the flow channel lengths occupied are the same.

[0050] As an optional embodiment of the above scheme of the present invention, see Figure 1-Figure 4The heat exchange body includes a flow channel plate 8 and an upper cover 7. The heat exchange chamber 9 is opened inward from one side surface of the flow channel plate 8. The outlet 2 and the inlet 1 are both opened on the flow channel plate 8. The heat exchange bodies in the sparse tooth section 3, the gas-liquid separation section 4 and the dense tooth section 5 are all arranged at the bottom of the heat exchange chamber 9. The upper cover 7 is fixedly connected to the flow channel plate 8 and seals the open end of the heat exchange chamber 9. For all heat exchange bodies, along the width direction of the straight fins, one side of the straight fins is located on the bottom surface of the heat exchange chamber 9, and the other side of the straight fins is against and sealed against the surface of the upper cover 7.

[0051] Example

[0052] See also Figure 1 The internal structure of the phase change cold plate in this embodiment utilizes a design concept of straight fins of varying areas, sizes, and inclinations. When the coolant first enters the phase change cold plate, it is entirely liquid. As the fluid flows, it absorbs heat and partially converts to gas.

[0053] like Figure 6 As shown in Figures (a) and (b), after the gas-liquid mixture flows into the gas-liquid separation section, due to the different densities of gas and liquid, the gas rises along the inclined flow channel of the gas-liquid separation section and flows toward the channel edge. The channel sidewalls of the rear section (i.e., dense-pitch section 5) are widened to ensure smooth gas outflow, improving the problem of gas difficulty in discharge due to narrow flow channels. The liquid flows toward the center of gas-liquid separation section 4 and then into the flow channel of dense-pitch section 5.

[0054] In the gas-liquid mixed working medium flowing into the dense-tooth segment 5, the proportion of liquid decreases, and the heat exchange area of ​​the fins of the dense-tooth segment 5 increases. The convective heat transfer effect is proportional to the heat exchange area, which makes up for the disadvantage of the small proportion of liquid at the rear end, so the heat exchange effect can achieve a uniform effect at the front and rear ends.

[0055] by Figure 1-Figure 5 The structural phase change cold plate shown in the figure is taken as an example, combined with Figure 5 as well as Figure 6 Take the above working mechanism as an example to illustrate: Figure 6 As shown, in the phase change cold plate of this embodiment, the gas flow direction schematic line is shown in FIG. Figure 6 In Figure (a), the liquid flow direction is shown in Figure 6 (b) in the figure. Figure 5 With the fin arrangement shown, the gas can be divided into eight different flow paths (see Figure 6 (a) in the figure). The gas generated by the sparse tooth segment rises vertically and is guided to the edge of the flow channel (i.e., the side wall of the heat exchange chamber 9) by the inclined straight fins in their respective flow directions. The gas generated by the inclined straight fins below is guided by the inclined straight fins above them, merges with the gas generated by the sparse tooth segment, and is discharged upward from the edge of the flow channel. Figure 6In (b) of the figure), the liquid will flow downward along the inclined straight fins due to gravity, and then flow into the center of the channel of the gas-liquid separation section 4, and then Number, The liquid flows in the dense tooth section 5.

[0056] Based on the above working mechanism, the fin arrangement requirements of this embodiment (taking the right fin as an example) are as follows:

[0057] 1. A certain distance is left between the end fins of each inclined straight fin (i.e., straight fin No. 2 11, straight fin No. 3 12, straight fin No. 4 13, and straight fin No. 5 14) and the edge of the channel (i.e., the side wall 9-1 of the heat exchange chamber) to ensure that the gas flows out from the edge of the channel;

[0058] 2. The end of the inclined fin close to the dense pitch section (i.e., the end (upper end) of the fifth straight fin 14) should at least be aligned with the outermost fin of the dense pitch section 5 heat exchanger, or extend to the right beyond the outermost fin of the dense pitch section to minimize the entry of gas into the heat exchanger of the dense pitch section 5.

[0059] 3. The starting end (i.e., the lower end) of the upper row of fins is located at the center of the adjacent lower row of fins. For example, the lower end of the third straight fin 12 is located above the midpoint of the first straight fin 10.

[0060] 4. The starting ends of the fins in the interlayers (such as the layer where the third straight fin 12 and the eighth straight fin 17 are located and the layer where the fifth straight fin 14 and the tenth straight fin 19 are located) are aligned (for example, the starting end of the third straight fin 12 is aligned with the starting end of the fifth straight fin 14) to ensure that the gas generated by the lower inclined fin (the third straight fin 12) can be guided to the edge of the flow channel by the upper fin (the fifth straight fin 14).

[0061] 5. The fin inclination angle is set to 45°. If the angle is too large, the liquid flowing down the inclined fin will have too high a velocity, generating vortexes with the incoming liquid from the sparse tooth section, which is not conducive to the liquid flowing into the dense fins; if the angle is too small, the gas rising resistance increases, which is not conducive to the gas flowing to the edge channel

[0062] 6. The fins on the left side can be arranged symmetrically along the center line (i.e. the center axis of inlet 1 and outlet 2).

[0063] by Figure 1-Figure 5 The model is used as an example to illustrate the design ideas:

[0064] The phase change cold plate is divided into three areas: I coarse tooth section 3, II gas-liquid separation section 4, and III dense tooth section 5. The fin size data of the three sections are shown in Table 1.

[0065] Table 1

[0066]

[0067] The distance between the dense tooth section 5 heat exchange body and the side wall of the heat exchange cavity 9 is 6.50mm. The minimum distance between the upper end of the straight fin far from the center axis of the inlet 1 in the gas-liquid separation section 4 and the side wall of the heat exchange cavity 9 is 2mm, and the distance between the upper end of the No.5 straight fin 14 in the gas-liquid separation section 4 and the lower end of the heat exchange body of the dense tooth section 5 is 0.06mm.

[0068] The cooling working medium enters from the phase change cold plate inlet 1 and exits from the outlet 2. In order to ensure the same heat exchange performance in the medium heat exchange process, the structure needs to be designed. Due to the need for uniform heat exchange, the following calculation formula can be listed:

[0069] Fluid phase change convection heat transfer:

[0070] (1-1)

[0071] Liquid flow rate, kg / s

[0072] Phase change latent heat, kJ / kg

[0073] Convection heat transfer, W

[0074] Convection heat transfer coefficient, W / m 2 ·K

[0075] Difference between wall temperature and incoming flow temperature, K

[0076] Convection heat transfer area, m 2

[0077] According to the above formula:

[0078] (1-2)

[0079] The heat exchange area of each section and the heat source surface is the same, so according to the heat flux formula:

[0080] (1-3)

[0081] Heat flux, W / m 2

[0082] Contact area with heat source surface, m 2

[0083] The heat absorption of each section of liquid can be obtained The same, the vaporization amount is also the same, and the liquid flow rate of each section can be obtained The ratio of the heat exchange area of each section is 1:1:1, and the ratio is substituted into formula (1-2) to obtain

[0084]

[0085]

[0086]

[0087] After calculation, the ratio of the heat exchange area of each section is 3:2:1. The ratio is substituted into formula (1-1) to obtain the ratio of the heat exchange Q of each section is 3:2:1, and the closer to the outlet, the less the heat exchange of the fluid. In order to make the heat exchange of each section uniform, different area fin channels are used, and according to Table 1, the ratio of the heat exchange area of each section is 25:28:93. The ratio of the heat exchange coefficient and the ratio of the heat exchange area are substituted into formula (1-1) to obtain

[0088]

[0089]

[0090]

[0091] After calculation, the ratio of the heat exchange of each section is 75:56:93, which greatly improves the uniformity compared with the traditional fin.

[0092] From the above scheme, it can be seen that the phase change working medium cold plate of the present application adopts different fin structures and flow channels combined with each other inside, which ensures that the working medium with different gas-liquid ratios will not cause the heat dissipation performance to decrease due to the change of the gas-liquid ratio in the heat exchange process, and can make the cold plate maintain the same heat exchange efficiency. Compared with the conventional cold plate flow channel, the present application sets the spacing and size of the fin reasonably, so that the fin area at different positions in the cold plate can adapt to the heat dissipation of the phase change working medium with different gas-liquid ratios, so as to ensure that the working medium can exchange heat with the same heat exchange efficiency whether it is low gas component or high gas component.

Claims

1. A phase change cold plate, characterized in that: The heat exchanger comprises a heat exchange body, a heat exchange cavity (9) is provided in the heat exchange body, an outlet (2) is provided at the upper end of the heat exchange cavity (9) on the heat exchange body, and an inlet (1) is provided at the lower end of the heat exchange cavity (9) on the heat exchange body, wherein both the outlet (2) and the inlet (1) are in communication with the heat exchange cavity (9); The heat exchange chamber (9) is provided with a sparse tooth section (3), a gas-liquid separation section (4) and a dense tooth section (5) from bottom to top, and a heat exchange body is provided in each of the sparse tooth section (3), the gas-liquid separation section (4) and the dense tooth section (5); a spacing is left between each heat exchange body and the side wall of the heat exchange chamber (9) in the horizontal direction, and the spacing between the heat exchange body of the dense tooth section (5) and the side wall of the heat exchange chamber (9) is greater than the spacing between the heat exchange body of the sparse tooth section (3) and the gas-liquid separation section (4) and the side wall of the heat exchange chamber (9); the heat exchange bodies are all straight fin type heat exchange bodies, wherein the length direction of the straight fins in the sparse tooth section (3) and the dense tooth section (5) is arranged along the vertical direction; the spacing between the straight fins in the sparse tooth section (3) is greater than the spacing between the straight fins in the dense tooth section (5), and the spacing between the straight fins in the gas-liquid separation section (4) is greater than the spacing between the straight fins in the dense tooth section (5) and smaller than the spacing between the straight fins in the sparse tooth section (3); The straight fins in the gas-liquid separation section (4) are arranged at an angle. The straight fins in the gas-liquid separation section (4) can guide the gas phase formed in the sparse tooth section (3) and the gas-liquid separation section (4) toward the side wall of the heat exchange cavity (9), and guide the liquid phase in the gas-liquid separation section (4) to the heat exchange body of the dense tooth section (5).

2. The phase change cold plate according to claim 1, characterized in that: The outlet (2) and the inlet (1) are vertically opposite to each other, and the heat exchange chamber (9), the sparse tooth section (3), the gas-liquid separation section (4), the dense tooth section (5) and each heat exchange body are symmetrical about the central axis of the outlet (2) and the inlet (1); The straight fins located on the same side of the central axis of the inlet (1) in the gas-liquid separation section (4) are parallel to each other, and channels for liquid cooling medium to flow are left between the straight fins located on both sides of the central axis of the inlet (1) in the gas-liquid separation section (4) and the central axis of the inlet (1).

3. The phase change cold plate according to claim 2, characterized in that: From bottom to top, the straight fins of the heat exchanger in the gas-liquid separation section (4) are divided into several layers, and each layer is provided with several straight fins; On one side of the central axis of the inlet (1): in the same layer, for two adjacent straight fins, the projections of the upper end of the previous straight fin and the lower end of the next straight fin on the horizontal plane overlap, and for the straight fin away from the central axis of the inlet (1), a preset distance is left between the upper end of the straight fin and the side wall of the heat exchange chamber (9); for two adjacent layers, the upper layer is provided with a straight fin above the intersection of the two adjacent straight fins of the lower layer, and a specific area of ​​the straight fin is opposite to the intersection position of the two adjacent straight fins of the lower layer, and the specific area is an area one-third to two-thirds away from the edge of the straight fin; for the uppermost layer, the upper end of the straight fin close to the central axis of the inlet (1) is at least aligned with the lower end of the outermost straight fin of the dense tooth section (5), or exceeds the lower end of the outermost straight fin of the dense tooth section (5) and extends to the side wall of the heat exchange chamber (9).

4. The phase change cold plate according to claim 3, characterized in that: At least two straight fins are provided in each layer, and the projected length of each straight fin on the horizontal plane is not less than the spacing between the straight fins in the sparse tooth section (3).

5. The phase change cold plate according to claim 1, characterized in that: The inclination angle of the straight fins of the heat exchanger in the gas-liquid separation section (4) is 43°-47°.

6. The phase change cold plate according to claim 1, characterized in that: A preset distance is left between the inlet (1) and the sparse tooth section (3), and the preset distance enables the fluid to fully develop and flow; A preset distance is left between the outlet (2) and the dense tooth section (5), and the preset distance enables the fluid to fully develop and flow.

7. The phase change cold plate according to claim 5, characterized in that: The cross-sectional shape of the portion of the heat exchange chamber (9) located between the inlet (1) and the sparse tooth section (3) is set to be an isosceles trapezoid, wherein the inlet (1) is set in the middle of the upper base of the isosceles trapezoid; The cross-sectional shape of the portion of the heat exchange chamber (9) located between the outlet (2) and the dense tooth section (5) is set to be an isosceles trapezoid, wherein the outlet (2) is set in the middle of the upper base of the isosceles trapezoid.

8. The phase change cold plate according to claim 1, characterized in that: The heat exchange areas on the heat exchange body and the heat source surface in the sparse tooth section (3), the gas-liquid separation section (4) and the dense tooth section (5) are the same, and the occupied flow channel lengths are the same.

9. The phase change cold plate according to claim 1, characterized in that: The heat exchange body comprises a flow channel plate (8) and an upper cover (7); the heat exchange chamber (9) is opened inward from one side surface of the flow channel plate (8); the outlet (2) and the inlet (1) are both opened on the flow channel plate (8); the heat exchange bodies in the sparse tooth section (3), the gas-liquid separation section (4) and the dense tooth section (5) are all arranged at the bottom of the heat exchange chamber (9); the upper cover (7) is fixedly connected to the flow channel plate (8) and seals the open end of the heat exchange chamber (9); For all heat exchange bodies, along the width direction of the straight fins, one side of the straight fins is located on the bottom surface of the heat exchange cavity (9), and the other side of the straight fins is against and sealed against the surface of the upper cover (7).

10. The operating method of the phase change cold plate according to any one of claims 1 to 9, characterized in that: The process includes the following: A fully liquid cooling medium enters the heat exchange chamber (9) from the inlet (1). As the cooling medium flows, part of the cooling medium absorbs heat and is converted into a gaseous state. After the cooling medium flows through the sparse tooth section (3), the inclined straight fins in the gas-liquid separation section (4) guide the gas in the cooling medium toward the side wall of the heat exchange chamber (9). The gas guided toward the side wall of the heat exchange chamber (9) rises along the channel between the heat exchange body in the gas-liquid separation section (4) and the side wall of the heat exchange chamber (9), and along the channel between the heat exchange body in the dense tooth section (5) and the side wall of the heat exchange chamber (9), and is discharged from the outlet (2). When the cooling medium flows through the heat exchange body in the gas-liquid separation section (4), the inclined straight fins in the gas-liquid separation section (4) guide the liquid cooling medium into the heat exchange body in the dense tooth section (5).

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