JP3908705B2 - Liquid cooling device and liquid cooling system - Google Patents

Description

  The present invention relates to a liquid cooling device and a liquid cooling system for cooling a heating element such as a semiconductor element with a refrigerant, and in particular, by promoting heat transfer from the heating element to the refrigerant, the heating element can be cooled uniformly and at the same time the flow rate of the refrigerant can be reduced. About things.

  2. Description of the Related Art Conventionally, a water-cooling structure for an electric device provided with a high heat-generating power element (heating element) such as an IGBT is known (see, for example, Patent Document 1).

  FIG. 37 is a configuration diagram showing an example of the liquid cooling system 10 in which the water cooling structure as described above is incorporated, and FIG. 38 is a longitudinal sectional view showing the liquid cooling device 30 incorporated in the liquid cooling system 10. The liquid cooling system 10 includes a refrigerant reservoir 11 that stores a liquid-phase refrigerant L, a pump 13 that is connected to the refrigerant reservoir 11 via a pipe 12 and sends out the refrigerant L, and a pipe 14 that is connected to the pump 13 and the refrigerant reservoir 11, respectively. , 15, the flow rate adjusting device 16 connected via the pipe 15, the liquid cooling device 30 connected to the flow rate adjusting device 16 via the pipe 17, and the heat exchange connected to the liquid cooling apparatus 30 via the pipe 18. And a pipe 20 connecting the heat exchanger 19 and the refrigerant reservoir 11. The refrigerant reservoir 11 is provided with a pressure adjusting device 21. The flow rate adjusting device 16 has a function of adjusting so that the refrigerant L having a predetermined flow rate is supplied to the liquid cooling device 30.

The liquid cooling device 30 includes a casing 31 in which a cooling channel 32 is formed inside a copper material, and a semiconductor element such as a high heat generating power element (heating element) P is mounted on the outer wall surface of the casing 31. A substrate S is attached. The high heat generating power element P is attached to the substrate S using solder, and the substrate S is connected using solder having a lower melting point than the solder attaching the high heat generating power element P to the substrate S. In addition, pure water or the like as the refrigerant L flows through the cooling flow path 32.
JP 2002-314281 A

  The liquid cooling system described above has the following problems. That is, in the liquid cooling device 30, the temperature of the refrigerant L rises as it goes downstream of the cooling flow path 32, and the flow path wall surface (heat transfer surface H) that transmits heat generated by the high heat generating power element P to the refrigerant L. The temperature boundary layer becomes thick and the heat transfer coefficient decreases. For this reason, there exists a problem that temperature becomes high, so that the high heat_generation | fever power element P mounted downstream of the cooling flow path 32 exists.

  In particular, since a module size is large in a semiconductor element such as a large-capacity power device, there is a tendency that the temperature difference between the semiconductor element located on the upstream side of the cooling flow path and the semiconductor element located on the downstream side becomes large.

  In a power device, the electrical conduction resistance is affected by the element temperature. Therefore, when the area of one element is large as in the case of using a plurality of elements or using a single wafer, the device performance depends on the temperature distribution. May not be able to be fully extracted. Generally, it is preferable to control the temperature difference within a plurality of elements in a module or within a single wafer to about 5 ° C. or less. In addition, since the temperature distribution generates a difference in thermal expansion inside the module, there is a possibility of adversely affecting the reliability of the solder joint surface and the like.

  On the other hand, in order to avoid such a problem caused by the temperature distribution, a method of increasing the flow rate of the refrigerant to reduce the temperature rise of the refrigerant L can be considered. A new problem arises in that the energy consumed in the process increases.

  Therefore, the present invention uniformly improves the electrical characteristics and mechanical reliability of the heating element by cooling the heating element uniformly, and at the same time obtains high cooling characteristics with a small refrigerant flow rate, and energy consumed for cooling. An object of the present invention is to provide a liquid cooling device and a liquid cooling system capable of reducing the above.

  In order to solve the above problems and achieve the object, the liquid cooling apparatus and the liquid cooling system of the present invention are configured as follows.

(1) In a liquid cooling apparatus that cools a heating element with a refrigerant, a main flow path through which the refrigerant flows and is thermally connected to the heating element, and a position further away from the heating element than the main flow path And a sub-flow path through which the refrigerant flows, and a communication flow path through which the refrigerant flows is provided between the main flow path and the sub-flow path.

(2) The liquid cooling apparatus according to (1), wherein a communication channel having a larger or larger diameter is provided on the downstream side than the upstream side of the main channel.

(3) In the liquid cooling device described in (1) above, the flow direction of the refrigerant in the main flow path and the flow direction of the refrigerant in the sub flow path are opposite to each other. Features.

( 4 ) In a liquid cooling system for cooling a heating element with a refrigerant, a liquid cooling device provided in the heating element, a pump that sends the refrigerant to the liquid cooling device, and a refrigerant sent by the pump is divided to The liquid cooling device includes a branch device that supplies the liquid cooling device and a heat exchanger that cools the refrigerant discharged from the liquid cooling device, and the liquid cooling device is thermally connected to the heating element while allowing the refrigerant to flow therethrough. And a sub-flow path that is provided at a position farther from the heating element than the main flow path and through which the refrigerant flows. The refrigerant is provided between the main flow path and the sub-flow path. A communication flow path for allowing flow is provided.

( 5 ) In a liquid cooling system for cooling a heating element with a refrigerant, a liquid cooling device provided in the heating element, a main channel pump for sending the refrigerant to the liquid cooling device, and the refrigerant in the liquid cooling device. A sub-flow channel pump to be sent and a heat exchanger for cooling the refrigerant discharged from the liquid cooling device, and the liquid cooling device allows the refrigerant supplied from the main flow channel pump to flow and A main channel thermally connected to the heating element, and a sub channel provided at a position farther from the heating element than the main channel and through which the refrigerant supplied from the sub channel pump flows. And a communication channel for allowing the refrigerant to flow between the main channel and the sub channel.

  According to the present invention, since the heating element can be uniformly cooled, the electrical characteristics and mechanical reliability of the heating element are improved, and at the same time, high cooling characteristics can be obtained with a small refrigerant flow rate. Energy can be reduced.

  In the liquid cooling device that cools the power element (heating element) P with the refrigerant L, the main flow path through which the refrigerant L flows and is thermally connected to the power element P is further separated from the power element P than the main flow path. And a sub-flow path through which the refrigerant L flows, and a communication flow path through which the refrigerant L flows is provided between the main flow path and the sub-flow path.

  FIG. 1 is a diagram showing a liquid cooling system 100 according to a first embodiment of the present invention. The liquid cooling system 100 includes a refrigerant reservoir 101 that stores a liquid-phase refrigerant L, a pump 103 that is connected to the refrigerant reservoir 101 via a pipe 102 and sends out the refrigerant L, and a pipe 104 that is connected to the pump 103 and the refrigerant reservoir 101, respectively. , 105, a flow control device 106 connected through the flow control device 106, a branch device 108 connected to the flow control device 106 through a pipe 107, and the branch device 108, the main flow pipe 109 and the sub flow pipe 110. A liquid cooling apparatus 200 connected via the pipe, a heat exchanger 112 connected to the liquid cooling apparatus 200 via a pipe 111, and a pipe 113 connecting the heat exchanger 112 and the refrigerant reservoir 101. Yes. The refrigerant reservoir 101 is provided with a pressure adjusting device 114.

  The flow rate adjusting device 106 has a function of adjusting the refrigerant L at a predetermined flow rate so as to be supplied to the liquid cooling device 200, and the flow path is configured by a valve based on a detection value from a flow rate sensor (not shown). The power supply to the pump 103 is controlled. A part of the refrigerant L is returned to the refrigerant reservoir 101 when the flow rate is made lower than the region suitable for stable operation of the pump 103. The branch device 108 includes a valve, a throttle mechanism, and the like.

  As shown in FIG. 2, the liquid cooling device 200 is provided in a casing 201, a main channel 210 provided in the casing 201, through which the refrigerant L flows, and the main channel 210 separated by a partition wall 220. And a secondary flow path 230. The material of the partition 220 is a metal having a lower thermal conductivity than copper, such as SUS304, so that the liquid-phase refrigerant L in the sub-channel 230 does not rise in temperature due to heat exchange with the liquid refrigerant in the main channel 210. Or heat-resistant plastic is desirable.

  A substrate S on which a power element (heating element) P is mounted is attached to the outer wall of the housing 201 on the main flow path 210 side. The main flow path 210 is connected to the main flow path pipe 109 described above, and the sub flow path 230 is connected to the sub flow path pipe 110 described above. The partition wall 220 is provided with a communication channel 221 that communicates the main channel 210 and the sub-channel 230.

  In the liquid cooling system 100 configured as described above, the power element P is cooled as follows. That is, the liquid-phase refrigerant L in the refrigerant reservoir 101 is pumped up by the pump 103 and introduced into the flow rate adjusting device 106. In the flow rate adjusting device 106, the flow rate of the refrigerant L is adjusted, and an excessive amount of the refrigerant L is returned into the refrigerant reservoir 101 through the pipe 105. Further, the refrigerant L having a predetermined flow rate is introduced into the branching device 108, and the branching device 108 divides the refrigerant L into the main flow path 210 and the sub flow path 230 at a predetermined ratio and supplies the refrigerant L to the liquid cooling apparatus 200.

  The refrigerant L supplied to the liquid cooling apparatus 200 is heated by the power element P and discharged from the liquid cooling apparatus 200 as described later. The refrigerant L discharged from the liquid cooling device 200 is cooled to a predetermined temperature by the heat exchanger 112 and returned to the refrigerant reservoir 101.

  Here, heat transfer in the liquid cooling apparatus 200 will be described. Heat from the power element P is radiated to the refrigerant L flowing through the main flow path 210 via the substrate S. On the other hand, the refrigerant L supplied into the sub-channel 230 flows into the main channel 210 via the communication channel 221. Since the communication flow path 221 is disposed on the downstream side of the partition wall 220, the temperature of the refrigerant L in the main flow path 210 is suppressed from rising even downstream, and the sub flow path 230 refrigerant L is further directed toward the heat transfer surface H. By ejecting, the temperature boundary layer can be thinned to improve the heat transfer coefficient. As a result, the plurality of power elements P can be uniformly cooled.

  As described above, according to the liquid cooling system 100 according to the first embodiment, since the heating element such as the power element P can be cooled uniformly, the electrical characteristics and mechanical reliability of the power element P can be reduced. At the same time, it is possible to reduce the energy consumed for cooling because high cooling characteristics can be obtained with a small refrigerant flow rate.

  Therefore, even a relatively large heat transfer surface H can be uniformly cooled, and is particularly suitable for cooling a power device having a high heat generation. Of course, the present invention can also be applied to small electronic devices such as personal computers.

  The branching device 108 and the flow rate adjusting device 106 may be disposed downstream of the pump 103 as an integrated device.

  FIG. 3 is a longitudinal sectional view showing a case where boiling cooling is performed in the liquid cooling apparatus 200. When the heat generation amount of the power element P is larger, or when the flow rate of the refrigerant L is small, it operates as a liquid cooling device utilizing the boiling phenomenon. In other words, boiling is a phenomenon in which the refrigerant undergoes a phase change from the liquid phase to the gas phase, and extremely high heat transfer performance can be obtained.

For example, when using a fluorocarbon as a refrigerant L, whereas a typical heat transfer rate by forced convection is 200~2000W / ^(m 2 K), in boiling such 2000~6000W / ^(m 2 K) A high heat transfer coefficient can be obtained (translated by Kayama Kaoru, Microelectronics Packaging Handbook, Nikkei Business Publications, 1991, p.138). Furthermore, in the boiling heat transfer of water by a smooth surface, the heat transfer coefficient reaches 100,000 W / (m ² K) or more, and an order of magnitude heat transfer performance can be expected for normal forced convection heat transfer. Moreover, since heat is transported by latent heat, a very high heat transport performance can be obtained compared to sensible heat, and the refrigerant flow rate can be reduced.

  Therefore, the use of the boiling phenomenon is extremely effective for energy saving and equipment miniaturization. However, when water is used as the refrigerant L, the boiling point at atmospheric pressure is 100 ° C., so the temperature of the semiconductor element is often higher than the allowable temperature of a semiconductor element using ordinary Si, such as SiC. It is suitable for cooling a semiconductor element capable of operating at a high temperature.

  For example, when a module is formed using SiC elements and cooling is performed by boiling water at approximately atmospheric pressure, high-temperature water of about 100 ° C. can be obtained downstream of the liquid cooling device. The more the refrigerant with a large difference from the ambient temperature is discharged, the more suitable it is for exhaust heat utilization. It is not only energy saving in the range of liquid cooling devices, but also the recovery of energy lost by semiconductor elements, SiC elements and water. The combination of boiling is excellent.

  On the other hand, when the boiling heat transfer of the refrigerant is used, the vapor bubbles M of the refrigerant L are generated in the main flow path 210. The vapor bubble M merges with other vapor bubbles M as it goes downstream, and becomes a large vapor bubble M. Eventually, the main flow path 210 becomes full of steam, and the heat transfer surface H is not wetted by the liquid-phase refrigerant L. In such a state, heat dissipation is hindered and there is a risk of falling into a burnout phenomenon. When the burnout phenomenon occurs, the heat transfer surface temperature rapidly rises and may reach 1000 ° C. or higher, and it is difficult to avoid damage to the equipment. Therefore, it is necessary to avoid the burnout phenomenon from the viewpoint of reliability and safety of the equipment.

  According to the liquid cooling device 200, the vapor bubble M can be condensed and collapsed by injecting the supercooled refrigerant L from the sub-flow channel 230 into the main flow channel 210 into the vapor bubble M. The phenomenon can be avoided. In addition, the supercooling degree of the refrigerant L in the main channel 210 can be controlled almost uniformly by supplying the refrigerant L having a high degree of supercooling to the downstream side of the main channel 210 of the refrigerant L having a low degree of supercooling. As a result, a plurality of elements can be cooled almost uniformly.

  FIG. 4 is a longitudinal sectional view showing a first modification of the liquid cooling apparatus 200 described above. In this figure, the same functional parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, the distribution of the communication channel 221 is different from that in FIG. That is, the installation density of the communication flow path 221 increases as it goes from the upstream to the downstream of the main flow path 210. With this configuration, the temperature of the refrigerant L in the main channel 210 can be finely controlled, and the plurality of power elements P can be cooled to a more uniform temperature.

  Instead of increasing the installation density, the inner diameter of the communication channel 221 may be increased as the main channel 210 moves from the upstream to the downstream.

  FIG. 5 is a longitudinal sectional view showing a second modification of the liquid cooling apparatus 200 described above. In this figure, the same functional parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, the main flow path 210 and the sub flow path 230 face each other in the direction in which the refrigerant L flows. That is, even if a material having low thermal conductivity is used for the partition wall 220, heat cannot be completely blocked. Therefore, the flow in the main flow path 210 and the sub flow path 230 are reversed in the same direction as in this modification. Flowing in the opposite direction can increase the degree of supercooling of the liquid-phase refrigerant L supplied downstream of the main flow path 210, and condenses and collapses the vapor bubbles M due to the injection of the liquid-phase refrigerant L. This can be done more effectively.

  FIG. 6 is a longitudinal sectional view showing a third modification of the liquid cooling apparatus 200 described above. In this figure, the same functional parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, by inserting the sub-flow channel 230 into the main flow channel 210 and disposing the power element P on both sides of the main flow channel 210, two sets of the main flow channel 210 and the sub-flow channel 230 can transfer two heat transfers. It becomes possible to cool the surface H. In the case of cooling two sets of modules each equipped with a plurality of power elements P, when the liquid cooling device 200 is attached to each module, the number of connection points of the input / output piping of the refrigerant L is four. On the other hand, in the liquid cooling device 200 of the present modification, there are two connection points of the input / output piping of the refrigerant L to the liquid cooling device 200. For this reason, the connection location of input-output piping can be reduced, and the structural reliability can be improved.

  FIG. 7 is a transverse sectional view showing a liquid cooling apparatus 300 incorporated in the liquid cooling system 100 according to the second embodiment of the present invention, and FIG. 8 is a longitudinal sectional view.

  The liquid cooling device 300 includes a housing 301, a main flow channel 310 provided in the housing 301 through which the refrigerant L flows, and a sub flow channel 330 provided in the main flow channel 310 separated by a partition wall 320. I have.

  A substrate S on which a power element (heating element) P is mounted is attached to the outer wall of the housing 301 on the main flow path 310 side. In FIG. 8, reference numeral 302 denotes a lid. The main flow path 310 is connected to the main flow path pipe 109 described above, and the sub flow path 330 is connected to the sub flow path piping 110 described above.

  A hole 311 is arranged on the most upstream side in the main flow path 310, and a bubble crushing member 312 is provided on the upstream side of a nozzle 321 described later. The bubble crushing member 312 has a bubble crushing member as will be described later. The bubble crushing member 312 includes a first plate group 313 projecting from the heat transfer surface H of the main flow path 310 and a second plate group 314 projecting from the facing surface F on the partition wall 322 side. Yes. The first plate group 313 and the second plate group 314 are attached with different angles with respect to the flow of the refrigerant L. The partition 320 is provided with a nozzle (communication channel) 321 that communicates the main channel 310 and the sub-channel 330.

  According to the liquid cooling apparatus 300 configured as described above, the heat generated in the power element P is transmitted to the refrigerant L flowing through the main flow path 310 in the same manner as the liquid cooling apparatus 200 described above, and the refrigerant L is transmitted. Boils on the hot surface H and generates a vapor bubble M. The supercooled refrigerant L is supplied to the nozzle position 321 through the sub-channel 330.

  The vapor bubble M is introduced into the bubble crushing member 312 and is divided when the dimension becomes larger than the gap between the first plate group 313 and the second plate group 314. Since the flow path in the gap between the first plate group 313 and the second plate group 314 is adjacent to the flow path 315 gradually widening to the downstream side and the flow path 316 gradually narrowing to the downstream side, When the divided vapor bubbles M exit the bubble crushing member 312, the position of the vapor bubbles M in the flow direction is shifted due to the difference in the flow velocity at the outlet between the adjacent flow paths. For this reason, in the flow path 315 spreading downstream, the vapor bubbles M are easily separated from the first plate group 313 and the second plate group 314, and the vapor bubbles M divided at the inlet of the bubble crushing member 312 are discharged from the bubble crushing member 312. It becomes difficult to unite. That is, it is difficult to form a large steam bubble M. Further, since the supercooled refrigerant L is supplied from the nozzle 321 to the downstream side of the bubble crushing member 312, the vapor bubbles M that are crushed and have a large surface area are mixed with the supercooled refrigerant L, and the vapor bubbles are mixed. M disappears or is reduced in volume. For this reason, it is possible to suppress the occurrence of the burnout phenomenon.

  As a method for forming the bubble crushing member 312, a plate group having the same direction may be provided on each of the heat transfer surface H and the opposing surface F, and machining such as cutting or a plurality of plates are arranged and brazed or caulked. When mounting by the method, manufacturing is easier than mounting plates with different angles alternately on one side. Moreover, it may be manufactured by a method in which a material is poured into a mold, such as die casting using metal material, casting, or resin injection molding, or all plates having different orientations on either the heat transfer surface H or the opposing surface F are used. They may be attached together. Further, a structure in which a structure holding a plate group with a frame is inserted into the main flow path 310 may be used.

  In the processing by cutting, for example, a material that can adopt a copper material having high thermal conductivity such as C1100 has a high manufacturing cost, and a material suitable for casting or die casting has low thermal conductivity. For this reason, whether the manufacturing method and the plate are attached to the heat transfer surface H, the attachment surface F, or the heat transfer surface H or the attachment surface F depends on the required heat radiation performance, cost, and reliability. To do. For example, if the opposing surface F side is made of resin and the bubble crushing member is manufactured by injection molding of resin integrally with the opposing surface F, the cost is low but the reliability is lower than that of a metal material. Although this is not the case, the heat dissipation performance is also reduced.

  FIG. 9 is a transverse sectional view showing a first modification of the liquid cooling apparatus 300 described above, and FIG. 10 is a longitudinal sectional view. In these drawings, the same functional parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted. In the bubble crushing member 312 in this modification, the plates constituting the first plate group 313 and the second plate group 314 are bent halfway. In the linear shape, the plate interval and the length of the bubble crushing member 312 in the flow direction cannot be handled as independent design parameters. However, by making a curve, these parameters can be freely changed independently. . For example, when the heat flux is high, the size of the vapor bubble M tends to increase, but even when the flow rate of the refrigerant L is large, the vapor bubble M has a flat shape extending in the flow direction, and thus the bubble crushing member 312. The length L in the mainstream direction must be increased to some extent.

  FIG. 11 is a schematic diagram showing the main part of the parallel fins incorporated in the liquid cooling apparatus 300. FIG. In the bubble crushing member 312 in this modification, the plates constituting the first plate group 313 and the second plate group 314 are arranged in parallel to each other, and the lower surface of the first plate group 313 is uneven. The upper surface of the second plate group 314 in the drawing is uneven.

  For this reason, the fluid resistance between the adjacent flow paths 315 and 316 partitioned by the plate is different due to the unevenness, and the flow rate of the refrigerant L is different. For this reason, after the vapor bubbles M are separated by the bubble crushing member 312, the time for the vapor bubbles M to be discharged to the outlet side of the bubble crushing member 312 shifts, so that the vapor bubbles M are unlikely to rejoin.

  12 is a transverse sectional view showing a second modification of the liquid cooling apparatus 300 described above, FIG. 13 is a longitudinal sectional view taken along the line 12A-12A in FIG. 12 and viewed in the direction of the arrow, and FIG. 14 is 12B in FIG. It is the longitudinal cross-sectional view cut | disconnected by the -12B line and looked at the arrow direction. In these drawings, the same functional parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  A bubble crushing member 340 is formed in the main channel 310. The bubble crushing member 340 includes a projection group 341 having a height that is approximately half the channel height of the main channel 310 and a similar projection group 342 provided on the facing surface F. A part of the steam bubbles M crushed on the inlet side of the bubble crushing member 340 is discharged to a position close to the heat transfer surface H, and the rest is discharged to a position close to the facing surface F.

  On the other hand, although the supercooled refrigerant L is ejected from the nozzle 321, the vapor bubble M discharged near the opposing surface F at the outlet of the bubble crushing member 340 is another vapor bubble M discharged from the opposing surface F to the same height. Since the refrigerant L is ejected into the gap between the two, it is difficult to unite with other bubbles. For this reason, it is possible to suppress the occurrence of the burnout phenomenon.

  The nozzle 321 may be disposed downstream of the projection group 342, or may be disposed at a position near the heat transfer surface H of the projection group 342 or on the side surface of the projection group 342.

  15 is an explanatory view showing the principle of the third modification of the liquid cooling apparatus 300 described above, FIG. 16 is a sectional view taken along the line 15A-15A in FIG. 15 and viewed in the direction of the arrow, and FIG. It is sectional drawing cut | disconnected by the -15B line | wire and seeing in the arrow direction.

  In this modification, a bubble crushing member 350 is provided. The bubble crushing member 350 includes a plurality of tubular members 351 to 353. The vapor bubble M introduced into the bubble crushing member 350 is crushed at the inlet. The separated vapor bubbles M are discharged from the outlet of the bubble crushing member 350 to a position different from the inlet in a cross section orthogonal to the flow direction of the refrigerant L. For this reason, it is difficult for the vapor bubbles M to be reunited. In addition, you may make it prevent the recombination of the vapor bubble M reliably by making the length of the tubular members 351-353 different, forming an unevenness | corrugation in an inner wall surface, etc.

  18 is a view showing a fourth modification of the liquid cooling device 300 described above, which is a cross-sectional view taken along the line 19A-19A in FIG. 19 and viewed in the direction of the arrow, and FIG. 19 is a line 18A-18A in FIG. It is sectional drawing cut | disconnected by and seen in the arrow direction. In these drawings, the same functional parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The bubble crushing member 360 includes a first plate group 361 provided on the heat transfer surface H and a second plate group 362 provided on the facing surface F. Each of the first plate group 361 and the second plate group 362 has a height that is about half of the flow path height of the main flow path 310, and is attached with different inclination angles with respect to the flow direction of the refrigerant L. . The main channel 310 is bent in different directions in the upper half and the lower half of the main channel 310 on the downstream side of the bubble crushing member 360 along the inclination of the plate group. A nozzle 321 for supplying the refrigerant L from the sub flow path 330 to the main flow path 310 is provided downstream of the bubble crushing member 360.

  Since the upper half and the lower half of the vapor bubbles M that have reached the bubble crushing member 360 and are divided are discharged in different directions, it is difficult to unite again. The first plate group 361 and the second plate group 362 have substantially the same height. For example, the height of the first plate group 361 is increased and the height of the second plate group 362 is decreased. Or vice versa.

  FIG. 20 is a longitudinal sectional view showing an essential part of a fifth modification of the liquid cooling apparatus 300 described above, and FIG. 21 is an explanatory view showing the operating principle. In these drawings, the same functional parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted. In the present modification, a bubble crushing member 370 is protruded from the main channel 310.

  The bubble crushing member 370 is formed in a protruding shape in which the upstream side is thin on the facing surface F and the downstream side is thick. A nozzle 321 is provided on the downstream end face of the bubble crushing member 370. Since the vapor bubbles M divided by the bubble crushing member 370 are separated from each other by the supercooled refrigerant L at the outlet of the bubble crushing member 370, the vapor bubbles M are difficult to recombine and at the same time, Heat exchange is also promoted, and the vapor bubbles M can be effectively eliminated or reduced in volume.

  FIG. 22 is a cross-sectional view showing the main part of a sixth modification of the liquid cooling apparatus 300 described above, and FIG. 23 is a vertical cross-sectional view showing the main part. In these drawings, the same functional parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, a recess 380 is provided in part of the main flow path 310 and immediately upstream of the above-described bubble crushing member 312 so as to increase the cross-sectional area in the direction orthogonal to the flow direction of the refrigerant L. .

  In general, when the flow velocity of the main flow path 310 is increased in order to improve the heat dissipation performance and the vapor bubbles M are elongated in the flow direction and become elongated, the number of divisions by the bubble crushing member 312 may be reduced. . For this reason, even if it passes through the bubble crushing member 312, the vapor bubbles M may remain in a relatively large state. On the other hand, in order to divide the bubbles into small pieces, the gaps between the plates of the bubble crushing member must be reduced. This increases fluid resistance and makes it difficult to manufacture.

  According to this modification, the flow rate of the refrigerant L flowing through the main channel 310 upstream of the bubble crushing member 312 is reduced, and the elongated vapor bubble M once becomes a flat shape. For this reason, the number of divisions of the vapor bubbles M can be increased, the pressure loss is small, and the bubble crushing member 312 can be easily manufactured.

  FIG. 24 is a plan view showing the main part of a liquid cooling apparatus 400 according to the third embodiment of the present invention, and FIG. 25 is a perspective view. In these drawings, the same functional parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The liquid cooling device 400 includes a casing 401, a main flow path 410 that is provided in the casing 401 and through which the refrigerant L flows, and a pair of substreams that are provided on both sides of the main flow path 410 and separated by a partition wall 420. Road 430 is provided.

  A substrate S on which a power element (not shown) is mounted is attached to the outer wall of the housing 401 on the main flow path 410 side. The main channel 410 is connected to the main channel pipe 109 described above, and the sub channel 430 is connected to the sub channel pipe 110 described above.

  A tubular path 431 is provided between the pair of sub flow paths 430. The tubular channel 431 is provided with a communication channel 432 through which the refrigerant L flows.

  According to the liquid cooling apparatus 400 configured as described above, the heat generated in the power element P is transmitted to the refrigerant L flowing through the main flow path 410 in the same manner as the liquid cooling apparatus 200 described above, and the refrigerant L is transmitted. Boils on the hot surface H and generates a vapor bubble M. The supercooled refrigerant L is supplied to the communication channel 432 through the tubular channel 431 by the sub-channel 430. The refrigerant L is ejected to the main flow path 310 through the communication flow path 432.

  According to the liquid cooling apparatus 400, the same effect as the liquid cooling apparatus 200 described above can be obtained. Further, the tubular passages 431 may be arranged substantially equally as shown in the figure, or the number of the tubular passages 431 may be increased toward the downstream side of the main flow path 410 or may be arranged only on the downstream side. In addition, the tubular passage 431 does not necessarily have to be orthogonal to the flow, and the cross-sectional area of the tubular passage 431 and the shape of the communication channel 432 provided in the tubular channel 431 control the ejection amount from each communication channel 432. Therefore, it may be changed depending on the place. Moreover, it is desirable to use a material having a low thermal conductivity so that the difference between the temperature of the refrigerant L to be ejected and the temperature of the refrigerant L in the main channel 410 is as large as possible. The refrigerant L flowing through the sub-flow path 430 is not the refrigerant L diverted from the main flow path 410 in front of the heat transfer surface H, but flows through the circulation path of a system different from that supplying the refrigerant L to the main flow path 410. May be.

  FIG. 26 is a plan view showing a main part of a first modification of the liquid cooling apparatus 400 described above. In this figure, the same functional parts as those in FIG. 24 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, the sub flow channel 430 is provided only on one side of the main flow channel 410. Note that the vicinity of the wall surface on the opposite side of the main channel 410 of the tubular channel 431, that is, the distal end portion farthest from the sub-channel 430 may be closed, or a hole similar to the communication channel 432 may be formed. Good.

  FIG. 27 is a perspective view showing a main part of a second modification of the liquid cooling apparatus 400 described above. In this figure, the same functional parts as those in FIG. 24 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, the outer shape of the tubular path 431 is circular.

  FIG. 28 is a perspective view showing an essential part of a third modification of the liquid cooling apparatus described above. In this figure, the same functional parts as those in FIG. 24 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, the outer shape of the tubular path 431 is an ellipse. For this reason, the fluid resistance of the refrigerant L flowing through the main flow path 410 can be reduced.

  FIG. 29 is a perspective view showing a main part of a fourth modification of the liquid cooling apparatus described above. In this figure, the same functional parts as those in FIG. 24 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, the outer shape of the tubular path 431 is an ellipse, and the bubble crushing member 433 is attached.

  FIG. 30 is a longitudinal sectional view showing a main part of a liquid cooling apparatus 500 according to the fourth embodiment of the present invention, and FIG. 31 is a transverse sectional view. In these drawings, the same functional parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The liquid cooling apparatus 500 includes a housing 501, a main channel 510 provided in the housing 501, through which the refrigerant L flows, and an impeller 520 disposed in the vicinity of the recess 511 of the main channel 510. . A substrate S on which the power element P is mounted is attached to the outer wall of the housing 501. The main flow path 510 is connected to the main flow path pipe 109 described above.

  The rotating shaft 521 of the impeller 520 is disposed at a position deviated from the center of the main flow path 510 by a predetermined amount, and the blade 522 is attached around the rotating shaft 521, and the tip of the blade 522 has a heat transfer surface H. It is supposed to pass through a place very close to. Note that a driving means such as a motor is not attached to the rotating shaft 521.

  In the liquid cooling apparatus 500 configured as described above, the impeller 520 is rotated by the flow of the refrigerant L flowing through the main flow path 510. As the impeller 520 rotates, the refrigerant L near the heat transfer surface H is agitated. For this reason, the temperature boundary layer formed in the vicinity of the heat transfer surface H can be broken and heat transfer can be promoted. Further, when the vapor bubble M is generated by boiling, the vapor bubble W is crushed by the blade 522, the vapor bubble M adhering to the heat transfer surface H is forcibly peeled off, and a burnout phenomenon is generated. Can be prevented.

  Since the rotation shaft 521 is displaced from the center of the main flow path 510, a part of the circumference of the impeller 522 enters a recess 511 in which the side wall of the main flow path 510 is expanded. The refrigerant L can also be effectively supplied to the heat transfer surface H by sending the supercooled refrigerant L from the flow path 530 through the communication flow path 531. Further, by adjusting the direction of the communication flow path 531 for supplying the refrigerant L, the force ejected by the refrigerant L may be used as power for rotating the impeller 520.

  The height of the blade 522 of the impeller 520 is substantially equal to the height of the main flow path 510, but the power for rotating the impeller 520 by the flow of the main flow path 510 or the flow of the refrigerant L supplied from the sub flow path 530. If there is no shortage, the blade height can be lowered. In this case, since the rotating blade 522 exists only near the heat transfer surface H, the fluid resistance of the refrigerant L flowing through the main flow path 510 is smaller than that when the blade height is high.

  32 is a cross-sectional view showing the main part of the first modification of the liquid cooling apparatus 500 described above, FIG. 33 is a front view showing an example of an impeller, and FIG. 34 is a front view showing another example of the impeller. In these drawings, the same functional parts as those in FIGS. 30 and 31 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, an axial flow impeller 540 is disposed in the main flow path 510. The rotating shaft 541 of the impeller 540 is parallel to the flow direction of the refrigerant L. One impeller 540 may be disposed in the main flow path 510, or a plurality of impellers 540 may be disposed. The rotating shaft 541 of the impeller 540 is provided with a plurality of blades 542, and the gap between the tip of the blade 542 and the heat transfer surface H is set to be narrow.

  FIG. 35 is a longitudinal sectional view showing a main part of a second modification of the liquid cooling apparatus 500 described above. In this figure, the same functional parts as those in FIGS. 30 and 31 are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, a plurality of impellers 540 are arranged in the flow direction of the refrigerant L. When the refrigerant flow rate in the main channel 510 is large, the vapor bubbles M generated by boiling have a shape extending in the flow direction. By arranging such an impeller 540, the vapor bubbles long in the flow direction are provided. M can also be divided.

  FIG. 36 is a diagram showing a configuration of a liquid cooling system 600 according to the fifth embodiment of the present invention. 36, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the liquid cooling system 600, two sets of pumps are provided instead of a combination of one pump and one branching device. The liquid cooling system 600 includes a refrigerant reservoir 601 that stores the liquid phase refrigerant L, a refrigerant main supply unit 610 that supplies the refrigerant L to the main flow path 210 of the liquid cooling apparatus 200, and a sub flow path 230 of the liquid cooling apparatus 200. A refrigerant sub-supply unit 620 for supplying the refrigerant L, a liquid cooling device 200, a heat exchanger 631 connected to the liquid cooling device 200 via a pipe 630, and the heat exchanger 631 and the refrigerant reservoir 601 are connected. And a piping 632 to be used. The refrigerant reservoir 601 is provided with a pressure adjusting device 602.

  The refrigerant main supply unit 610 is connected to the refrigerant reservoir 601 via a pipe 611 and sends out the refrigerant L, and a flow rate adjusting device 615 connected to the pump 612 and the refrigerant reservoir 601 via pipes 613 and 614, respectively. It has. The flow rate adjusting device 615 is connected to the main flow path 210 via a pipe 616.

  The flow rate adjusting device 615 has a function of adjusting the refrigerant L at a predetermined flow rate so as to be supplied to the main flow path 210, and throttles the flow path with a valve based on a detection value from a flow rate sensor (not shown). Alternatively, the power supply to the pump 612 is controlled. Note that when the flow rate is made lower than the region suitable for stable operation of the pump 621, a part of the refrigerant L is returned to the refrigerant reservoir 601.

  The refrigerant sub-supply unit 620 is connected to the refrigerant reservoir 601 via a pipe 621 and sends out the refrigerant L, and the flow rate adjusting device 625 connected to the pump 622 and the refrigerant reservoir 601 via pipes 623 and 624, respectively. It has. The flow rate adjusting device 625 is connected to the main flow path 230 via a pipe 626.

  The flow rate adjusting device 625 has a function of adjusting the refrigerant L at a predetermined flow rate so as to be supplied to the sub flow path 230, and the flow path is controlled by a valve based on a detection value from a flow rate sensor (not shown). The power supply to the pump 622 is controlled. It should be noted that a part of the refrigerant L is returned to the refrigerant reservoir 601 when the flow rate is made lower than the region suitable for stable operation of the pump 622.

  In this way, when the refrigerant L introduced into the main flow path 210 and the refrigerant L introduced into the sub flow path 230 are in different systems, the temperatures at the module inlets of the respective refrigerant L can be controlled separately. In addition, the temperature of the refrigerant L supplied to the sub flow path 230 can be lower than the temperature of the refrigerant L supplied to the main flow path 210. At this time, the same effect can be expected even if the refrigerant flow rate supplied to the sub-channel 230 is smaller than the case where the refrigerant temperatures supplied to the main channel 210 and the sub-channel 230 are the same.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid cooling apparatus and liquid cooling system which can reduce the flow volume of a refrigerant | coolant while being able to cool a heat generating body uniformly by promoting the heat transfer from a heat generating body to a refrigerant | coolant are obtained.

The figure which shows the structure of the liquid cooling system which concerns on the 1st Embodiment of this invention. The longitudinal cross-sectional view which shows the principal part of the liquid cooling apparatus integrated in the liquid cooling system. The longitudinal cross-sectional view which shows the effect | action of the liquid cooling device. The longitudinal cross-sectional view which shows the 1st modification of the liquid cooling device. The longitudinal cross-sectional view which shows the 2nd modification of the liquid cooling device. The longitudinal cross-sectional view which shows the 3rd modification of the liquid cooling device. The cross-sectional view which shows the liquid cooling device integrated in the liquid cooling system which concerns on the 2nd Embodiment of this invention. The longitudinal cross-sectional view of the liquid cooling device. The cross-sectional view which shows the 1st modification of the liquid cooling device. The longitudinal cross-sectional view of the liquid cooling device. The schematic diagram which shows the principal part of the parallel fin integrated in the liquid cooling device. The cross-sectional view which shows the 2nd modification of the liquid cooling device. The longitudinal cross-sectional view which cut | disconnected the liquid cooling device by the 12A-12A line | wire in FIG. 12, and looked at the arrow direction. The longitudinal cross-sectional view which cut | disconnected the liquid cooling device by the 12B-12B line | wire in FIG. 12, and looked at the arrow direction. Explanatory drawing which shows the principle of the 3rd modification of the liquid cooling device. Sectional drawing which cut | disconnected the principal part of the liquid cooling device by the 15A-15A line in FIG. 15, and looked at the arrow direction. Sectional drawing which cut | disconnected the principal part of the liquid cooling device by the 15B-15B line | wire in FIG. 15, and looked at the arrow direction. It is a figure which shows the 4th modification of the liquid cooling device, Comprising: Sectional drawing cut | disconnected by the 19A-19A line | wire in FIG. Sectional drawing which cut | disconnected the liquid cooling device by the 18A-18A line in FIG. 18, and looked at the arrow direction. The longitudinal cross-sectional view which shows the principal part of the 5th modification of the liquid cooling device. Explanatory drawing which shows the operating principle of the liquid cooling device. The cross-sectional view which shows the principal part of the 6th modification of the liquid cooling device. The longitudinal cross-sectional view which shows the principal part of the liquid cooling device. The top view which shows the principal part of the liquid cooling device which concerns on the 3rd Embodiment of this invention. The perspective view which shows the liquid cooling device. The top view which shows the principal part of the 1st modification of the liquid cooling device. The perspective view which shows the principal part of the 2nd modification of the liquid cooling device. The perspective view which shows the principal part of the 3rd modification of the liquid cooling device. The perspective view which shows the principal part of the 4th modification of the liquid cooling device. The longitudinal cross-sectional view which shows the principal part of the liquid cooling device which concerns on the 4th Embodiment of this invention. The cross-sectional view which shows the principal part of the liquid cooling device. Sectional drawing which shows the principal part of the 1st modification of the liquid cooling device. The front view which shows an example of the impeller integrated in the liquid cooling device. The front view which shows another example of the impeller integrated in the liquid cooling device. The longitudinal cross-sectional view which shows the principal part of the 2nd modification of the liquid cooling device. The figure which shows the structure of the liquid cooling system which concerns on the 5th Embodiment of this invention. The figure which shows an example of a liquid cooling system. The longitudinal cross-sectional view which shows the liquid cooling apparatus integrated in the liquid cooling system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100,600 ... Liquid cooling system, 200,300,400,500 ... Liquid cooling device, P ... Power element (heating element), L ... Refrigerant.

Claims (5)

In a liquid cooling device that cools a heating element with a refrigerant,
A main flow path through which the refrigerant flows and is thermally connected to the heating element;
Provided in a position farther from the heating element than the main flow path, and a sub flow path through which the refrigerant flows,
A liquid cooling apparatus, wherein a communication channel for allowing the refrigerant to flow therethrough is provided between the main channel and the sub channel.   The liquid cooling device according to claim 1, wherein a communication channel having a larger or larger diameter is provided on the downstream side than the upstream side of the main channel.   The liquid cooling device according to claim 1, wherein a flow direction of the refrigerant in the main flow path and a flow direction of the refrigerant in the sub flow path are opposite to each other. In a liquid cooling system that cools a heating element with a refrigerant,
A liquid cooling device provided in the heating element;
A pump for sending refrigerant to the liquid cooling device;
A branch device for diverting the refrigerant sent by the pump and supplying the refrigerant to the liquid cooling device;
A heat exchanger for cooling the refrigerant discharged from the liquid cooling device,
The liquid cooling device includes a main flow path through which the refrigerant flows and is thermally connected to the heating element;
Provided in a position farther from the heating element than the main flow path, and a sub flow path through which the refrigerant flows,
A liquid cooling system, wherein a communication channel for allowing the refrigerant to flow is provided between the main channel and the sub channel. In a liquid cooling system that cools a heating element with a refrigerant,
A liquid cooling device provided in the heating element;
A main channel pump for sending the refrigerant to the liquid cooling device;
A sub-channel pump for sending the refrigerant to the liquid cooling device;
A heat exchanger for cooling the refrigerant discharged from the liquid cooling device,
The liquid cooling device includes a main flow path through which the refrigerant supplied from the main flow path pump flows and is thermally connected to the heating element;
Provided in a position farther from the heating element than the main flow path, and a sub flow path through which the refrigerant supplied from the sub flow path pump flows,
A liquid cooling system, wherein a communication channel for allowing the refrigerant to flow is provided between the main channel and the sub channel.

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