CN1719182A - CPC system having plane type capillary core evaporator and condenser - Google Patents

Abstract

The invention discloses a CPL system with a planar capillary evaporator and a condenser. The structure of the CPL system is that the steam outlet of the evaporator is connected with the steam inlet of the condenser, and the liquid storage is connected with the condensate outlet of the condenser. The evaporator is a planar capillary evaporator, and the condenser is a planar capillary condenser; the liquid receiver is connected to the drain port of the condenser; the condensate outlet of the condenser passes through the subcooler and evaporates connected to the reflux liquid inlet of the device. The system starts quickly, runs stably, has simple structure, convenient adjustment, strong self-adaptive ability, good temperature control effect, and high heat transfer efficiency. It is an ideal device for cooling laptop or desktop computer chips and other high heat flux electronic equipment or devices It has high development value and broad market application prospect.

Description

CPL system with planar capillary evaporator and condenser

technical field

The present invention relates to a CPL system having an evaporator and a condenser.

Background technique

CPL (Capillary Pumped Loop: capillary pump suction two-phase fluid circuit) is a phase change heat transfer device that relies on capillary suction to drive the circulation of working fluid. It has strong heat transfer capacity, good isothermal performance, high temperature control accuracy and low energy consumption Low heat sharing and no moving parts make them ideal for cooling electronic devices. The CPL system mainly relies on the liquid working fluid to absorb heat in the evaporator and the vapor-phase working medium in the condenser to release heat to achieve heat transfer.

As shown in Figure 1, the existing CPL system mainly includes an evaporator, a condenser, a liquid receiver, and steam and liquid pipelines. Both the evaporator and condenser adopt a circular tube structure. The evaporator is the main part of the system to absorb heat, and the condenser is the main part of the system to dissipate heat. When the heat load acts on the surface of the evaporator, the liquid working medium in the capillary structure of the evaporator undergoes a vaporization phase change when heated, and the heat is removed from the heat source; in the condenser, the vapor phase working medium undergoes a condensation phase change and transfers heat to the outside , the capillary suction force generated by the capillary core of the evaporator makes the condensed liquid in the condenser return to the evaporator to complete the system cycle, and adjust the working temperature of the system and the amount of circulating working fluid through the liquid reservoir.

The disadvantages of the existing CPL system are: ①It is difficult to start the CPL system; ②During operation, due to the instability of the vapor-liquid two-phase flow in the condenser, it is easy to cause temperature and pressure fluctuations in the system. During operation, when the working conditions change, sometimes the evaporator will burn out, resulting in operation failure.

Therefore, in the system design of CPL, improving the start-up performance of the system, reducing the temperature and pressure shock of the system, and enhancing the robustness and reliability of the system have become a research focus of the current CPL system design.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a CPL system with a planar capillary evaporator and a condenser. The system starts quickly, operates stably, is simple in structure, easy to adjust, and has strong self-adaptive ability , good temperature control effect.

In order to achieve the above object, the technical solution adopted by the present invention is a CPL system with a planar capillary evaporator and a condenser, the steam outlet of the evaporator is connected with the steam inlet of the condenser, and it is characterized in that: the evaporator The evaporator is a planar capillary evaporator, and the condenser is a planar capillary condenser; the liquid inlet and outlet of the liquid receiver are connected to the drain port and condensate outlet of the condenser, and the condensate outlet of the condenser passes through the subcooler Connected to the reflux liquid inlet of the evaporator.

Compared with the prior art, the present invention has the following advantages:

(1) The unique design of the present invention enables the CPL system to start quickly, run stably and be easily adjusted.

When the invention is running stably, the working fluid enters and exits the condenser in the mode of "one in and one out". If the liquid flowing out of the condenser carries steam, the supercooler can completely condense it into liquid, and after being cooled by the cooler, it can be refluxed The liquid to the evaporator has a large degree of subcooling, thus improving the stability of the system and improving the operating performance of the system.

When the load condition, evaporating temperature or system pressure changes, the system needs to be dynamically adjusted. The liquid flows out from the liquid outlet and the liquid outlet; or the steam enters the condenser through the liquid inlet, the condensate flows out from the liquid outlet, and the liquid flowing out of the liquid receiver flows into the condensate through the liquid outlet, and the liquid receiver absorbs it and is discharged from the condenser The liquid or the liquid needed for the movement of the interface of the condenser is beneficial to the adjustment of the condensation area of the condenser and improves the self-regulation ability of the system.

(2) The condenser of the present invention is designed as a planar capillary core structure, which improves the condensation efficiency and does not require auxiliary starting heaters, coolers for liquid storage and other components.

When the steam pushes away the liquid level in the condenser channel, part of the liquid flowing out of the condenser liquid outlet enters the liquid receiver, and the other part enters the liquid inlet of the evaporator. Due to the large amount of work involved in the system circulation, the system’s Improved performance.

Adding a capillary core to the condenser and using a porous physical interface can make the steam in the condenser condense to form a stable physical interface, thereby suppressing or even eliminating the temperature and pressure fluctuations of the system.

(3) The evaporator of the present invention is designed as a planar capillary core structure. This evaporator has a flexible cooling method for the heat-dissipated equipment or devices, and has enhanced anti-drying ability, which increases the reliability of the system.

(4) The planar capillary evaporator is designed as another reverse planar capillary structure. Due to the reverse structure, the driving force of the system is increased, which is more conducive to the circulation of the system working fluid.

The heat sink is arranged on the outer surface of the upper cover, which increases the outer surface area of the evaporator, so that the evaporator can not only use the internal liquid working fluid vaporization phase change heat transfer, but also use the outer surface to dissipate heat to the surrounding environment. In the same capillary Under the structure, the heat transfer capacity of the system is correspondingly improved, and the structure of the system is more compact, which can improve the heat dissipation capacity of the system in a limited space.

(5) The capillary cores in the evaporator and condenser of the present invention can be made by compacting multi-layer wire mesh, so the production is simple, no special equipment is needed, and the development cost of the system is reduced.

Description of drawings

FIG. 1 is a schematic structural diagram of an existing CPL system.

Fig. 2 is a structural schematic diagram of an embodiment of the present invention.

Fig. 3 is a schematic structural view of an embodiment of the planar capillary condenser in Fig. 2 .

Fig. 4 is a sectional view along A-A of Fig. 3 .

Fig. 5 is a schematic structural diagram of the base in Fig. 3 .

Fig. 6 is a top view of the base in Fig. 3 .

FIG. 7 is a schematic structural view of the upper cover in FIG. 3 .

Fig. 8 is a bottom view of the upper cover in Fig. 3 .

Fig. 9 is a schematic structural view of an embodiment of the planar capillary evaporator in Fig. 2 .

Fig. 10 is a B-B sectional view of Fig. 9 .

Fig. 11 is a schematic structural view of another embodiment of the planar capillary evaporator in Fig. 2 .

Fig. 12 is a C-C sectional view of Fig. 11 .

Fig. 13 is a performance test diagram of the CPL prototype of the present invention. The abscissa is time, the first ordinate is temperature, and the second ordinate is heat load.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 2, the evaporator 1 is a planar capillary evaporator, and the condenser 2 is a planar capillary condenser; the steam outlet b of the evaporator 1 is connected to the steam inlet c of the condenser 2, and the liquid reservoir 3 The liquid inlet and outlet f of the condenser 2 are connected to the liquid discharge port d and the condensate outlet e of the condenser 2, and the condensate outlet e of the condenser 2 is connected to the reflux liquid inlet a of the evaporator 1 through the subcooler 4 .

When the present invention runs stably, the steam produced in the evaporator 1 enters the condenser 2 through the steam outlet b through the steam pipe and enters the condenser 2 through the steam inlet c, and returns through the liquid outlet e through the cooler 4 and the reflux liquid inlet a of the evaporator 1 after condensation The evaporator 1 completes the cycle; when the load condition, evaporating temperature or system pressure changes and the system needs to be dynamically adjusted, the method of heating and controlling the temperature of the liquid reservoir 3 is adopted, and the liquid inlet and outlet f of the liquid reservoir 3 , the liquid outlet d of the condenser 2 and the condensate outlet e control the exchange of the liquid working medium between the liquid receiver 3 and the system, so as to realize the improvement of the liquid working medium quality of the liquid receiver 3 on the condensate level of the condenser 2 and the circulating working medium of the system control to make the system run stably.

Subcooler 4 can adopt circular tube structure, is made of light tube, and its shape is coiled tube, and the diameter of pipeline depends on specific conditions.

The liquid reservoir 3 is a container structure, which can be made by welding a circular tube with a large diameter, or can be machined from a rod-shaped metal material, and its volume depends on the working requirements of the system.

The selection of the evaporator 1, the condenser 2, the liquid receiver 3, the subcooler 4 and the material of the vapor-liquid pipeline are all related to the compatibility of the selected working fluid. Available in brass or stainless steel.

The capillary cores in the evaporator 1 and condenser 2 are formed by pressing multi-layer wire mesh or sintering powder materials, such as multi-layer pressing of copper wire mesh with relatively large thermal conductivity.

As shown in Figures 3 to 8, the structure of the planar capillary wick condenser 2 is as follows: comprising a base 6, an upper cover 9, and a capillary wick 11, the base 6 and the upper cover 9 are fixed and sealed; 7. The second partition 16 divides the base 6 into a steam collection chamber 8, a first liquid collection chamber 5, and a second liquid collection chamber 15. The first liquid collection chamber 5 is composed of a transverse channel and a longitudinal channel, and the cross arrangement , a condensate outlet e is opened on the first liquid collection chamber 5, a steam inlet c is opened on the steam collection chamber 8, a liquid discharge port d is opened on the second liquid collection chamber 15; There are steam channels 10, steam condensation channels 13, and liquid channels 14. The steam condensation channels 13 are composed of longitudinal channels. The steam channels 10 are connected to the steam collecting chamber 8 and the steam condensation channels 13, and the liquid channels 14 are connected to the steam condensation channels 13. And the second liquid collection chamber 15; the capillary core 11 is placed between the steam condensation channel 13 and the first liquid collection chamber 5. It can be seen from Fig. 3 to Fig. 8 that the first liquid collecting chamber 5 is composed of one transverse channel and seven longitudinal channels, and the steam condensation channel 13 is composed of seven longitudinal channels.

The first liquid collecting chamber 5 has a plurality of longitudinal channels, and a plurality of transverse channels, and the transverse channels and the longitudinal channels may or may not be perpendicular to each other. There are also multiple longitudinal channels for the steam condensation channel 13 . The cross-sectional shape of the channel is rectangular, or other shapes such as trapezoid.

In order to improve the heat dissipation efficiency of the condenser, the upper cover 9 is made of a metal material with a high thermal conductivity, such as copper or aluminum. The connection between the upper cover 9 and the base 6 can be welded, or flanged bolted connection. The sealing form is an O-ring, and the capillary core 11 can be easily replaced by the flanged bolted connection.

The capillary wick 11 is placed between the first liquid collection chamber 5 and the steam condensation channel 13, and the capillary wick 11 is directly in contact with the fins 17 of the first liquid collection chamber and the fins 18 of the steam condensation channel. Due to the existence of the capillary wick 11, The condensation interface can be stabilized on the upper surface of the capillary wick 11, so that the condensed liquid can enter the first liquid collection chamber 5 through the capillary wick 11, and enter the return liquid pipeline through the condensate outlet e, reducing or even eliminating the fluctuation of the condensation interface , which enhances the stability of the system.

When working, the cold source is in contact with the cold surface 12 of the upper cover 9, and the steam flowing from the evaporator 1 enters the steam collection chamber 8 through the steam inlet c, and then the steam collection chamber 8 passes through the steam channel 10 to uniformly distribute the steam working medium Distributed to the steam condensation channel 13, condensed on the surface of the steam condensation channel 13 and the capillary core 11, releases heat, which is transferred to the cold surface 12 through the fins 18 of the steam condensation channel, taken away by the cooling load, and the condensate flows through the capillary The core 11 is collected into the first liquid collecting chamber 5, and the condensate outlet e of the first liquid collecting chamber 5 passes through the cooler 4 and the return liquid inlet a returns to the evaporator 1, completing a heat exchange cycle process.

If the evaporating temperature of the system increases, the condensation capacity and condensation area need to increase, the condensation interface in the steam condensation channel 13 of the condenser 2 will move to the right under the push of the steam, and the excess liquid in the condenser 2 will be released from the condenser 2 If the evaporation temperature of the system decreases and the condensation volume and condensation area need to be reduced, the condensation rate of the steam will be accelerated, and the condensation interface in the steam condensation channel 13 of the condenser 2 will move to the left. At the same time, the liquid reservoir The liquid in 3 flows into the liquid outlet d of the condenser 2 from the liquid inlet and outlet f.

As shown in Figures 9 to 10, a structure of the planar capillary wick evaporator 1 is: comprising a base 20, an upper cover 21, and a capillary wick 22, the base 20 and the upper cover 21 are fixed and sealed; 27 divides the base 20 into a liquid collection chamber 19 and a steam collection chamber 26. The liquid collection chamber 19 is composed of a horizontal channel and a longitudinal channel, and is arranged in a cross direction. There is a backflow liquid inlet a on the liquid collection chamber 19. There is a steam outlet b on the chamber 26; a steam channel 23 and a steam channel 24 are opened on the upper cover 21, the steam channel 23 is composed of longitudinal channels, and the steam channel 24 communicates with the steam channel 23 and the steam collecting chamber 26; The core 22 is placed between the liquid collection chamber 19 and the steam channel 23 .

The number of the liquid collecting chamber 19 is one or more transverse grooves, and the number of longitudinal grooves is multiple. The transverse grooves and the longitudinal grooves may be perpendicular to each other or not. The steam channel 23 has a plurality of longitudinal channels. The cross-sectional shape of the channel is rectangular, or other shapes such as trapezoid.

The capillary wick 22 is placed between the liquid collecting chamber 19 and the steam channel 23. The capillary wick 22 is directly in contact with the fins of the liquid collecting chamber and the fins of the steam channel. liquid.

When working, the heating surface 25 of the upper cover of the evaporator 1 is directly attached to the load surface, the heating surface 25 absorbs heat, and the heat is quickly transferred to each steam channel fin, so that the capillary core 22 that is in direct contact with the steam channel fins The liquid working medium is rapidly heated to the saturation temperature and vaporized. The steam formed after vaporization flows along the steam channel 23 to the steam collection chamber 26, and flows into the steam inlet c of the condenser 2 through the steam outlet b through the steam pipe. If liquid droplets are entrained, they can be collected in the steam collection chamber 26. After the heat is released in the condenser 2, the steam condenses into a liquid, and then, under the action of the capillary suction force generated by the phase change of the capillary core working medium vapor and liquid, it enters from the condensate outlet e through the cooler 4 and the reflux liquid inlet a In the liquid collection chamber 19 of the evaporator 1, the liquid working medium is evenly distributed in the liquid collection chamber 19 under the action of the fluid distributor formed by the liquid collection chamber 19, enters the capillary wick 22, and flows to the vapor-liquid phase transition interface.

As shown in Figures 11 to 12, another structure of the planar capillary wick evaporator 1 includes a base 33, an upper cover 28, and a capillary wick 36, the base 33 and the upper cover 28 are fixed and sealed; The plate 31 divides the upper cover 28 into a liquid collection chamber 30 and a steam collection chamber 32. The liquid collection chamber 30 is composed of a transverse channel and a longitudinal channel, and is arranged crosswise. There is a backflow liquid inlet a on the liquid collection chamber 30. There is a steam outlet b on the steam collecting chamber 32; a steam channel 35 and a steam channel 34 are opened on the base 33, the steam channel 35 is composed of longitudinal channels, and the steam channel 34 communicates with the steam channel 35 and the steam collecting chamber 32; The capillary wick 36 is placed between the liquid collection chamber 30 and the steam channel 35 .

Radiating fins 29 are preferably provided on the outer surface of the upper cover 28 .

The number of the liquid collection chamber 30 is one or more transverse channels, and the number of longitudinal channels is multiple. The transverse channels and the longitudinal channels may or may not be perpendicular to each other. The steam channel 35 has a plurality of longitudinal channels. The cross-sectional shape of the channel is rectangular, or other shapes such as trapezoid.

During operation, the heating surface of the lower surface of the evaporator 1 is directly in contact with the load surface, and absorbs heat by heat conduction. There are many parallel steam channel fins on the base 33, which are in direct contact with the capillary wick 36, which is filled with liquid working medium. When the heating surface absorbs heat, it is transferred to the evaporator through two paths: part of the heat is quickly transferred to the liquid working medium in the capillary wick 36 through the fins of the steam channel; the other part is transferred to the heat sink on the upper surface of the evaporator through the wall 29. The liquid working medium in the capillary wick 36 that is in direct contact with the fins of the steam channel is rapidly heated to the saturation temperature and vaporized, and the steam formed after vaporization flows to the steam collecting chamber 32 along the steam channel 35 and through the steam channel 34, and then Through the steam outlet b, it flows into the steam inlet c of the condenser 2 through the steam pipe. If liquid droplets are entrained, they may be deposited in the trap chamber 32 .

After the steam releases heat in the condenser 2 and cools down, the steam condenses into a liquid. Under the action of the capillary suction force generated by the phase change of the working medium vapor and liquid in the capillary core of the evaporator, it passes through the reflux liquid inlet a of the evaporator 1 along the liquid pipeline Entering the liquid collection chamber 30, the liquid working medium is under the action of the fluid distributor formed by the vertical and horizontal channels of the liquid collection chamber 30, and the return liquid is evenly distributed to the capillary core 36, and flows to the vapor-liquid phase change interface for the next time of the system. cycle.

As shown in Figure 13, the system starts at 100W, and then changes the system operating status after the heat load is changed. As can be seen from the figure, the planar CPL system of the present invention has good start-up performance. Once the system is started, it runs stably without fluctuations; when the system runs stably, changing the thermal load, the system still runs stably, and the operating temperature of the system is slightly lower. change, but within 2°C.

Claims (7)

1. A CPL system with planar capillary evaporator and condenser, the steam outlet of evaporator is connected with the steam inlet of condenser, it is characterized in that: The evaporator (1) is a planar capillary evaporator, and the condenser (2) is a planar capillary condenser; The liquid inlet and outlet (f) of the liquid receiver (3) is connected with the liquid outlet (d) and the condensate outlet (e) of the condenser (2), and the condensate outlet (e) of the condenser (2) passes through The cooler (4) is connected to the reflux liquid inlet (a) of the evaporator (1). 2. The CPL system with planar capillary evaporator and condenser according to claim 1, characterized in that: the structure of the planar capillary condenser (2) includes a base (6), a loam cake (9), the capillary core (11), the base (6) and the loam cake (9) are fixed and sealed; the first partition (7), the second partition (16) separates the base (6) into steam-collecting Cavity (8), the first liquid collection chamber (5), the second liquid collection chamber (15), the first liquid collection chamber (5) is composed of transverse grooves and longitudinal grooves, and arranged crosswise, in the first liquid collection chamber There is a condensate outlet (e) on the chamber (5), a steam inlet (c) on the steam collecting chamber (8), and a liquid discharge port (d) on the second liquid collecting chamber (15); The upper cover (9) is provided with a steam channel (10), a steam condensation channel (13), and a liquid channel (14). The steam condensation channel (13) is composed of longitudinal channels, and the steam channel (10) communicates with the steam collecting chamber (8) and the steam condensation channel (13), the liquid channel (14) communicates with the steam condensation channel (13) and the second liquid collection chamber (15); the capillary core (11) is placed in the steam condensation channel (13) and Between the first liquid collecting chamber (5). 3. The CPL system with planar capillary evaporator and condenser according to claim 1 or 2, characterized in that: the structure of the planar capillary evaporator (1) includes a base (20), The upper cover (21), the capillary core (22), the base (20) and the upper cover (21) are fixed and sealed; the partition (27) separates the base (20) into a liquid collection chamber (19), a steam collection chamber (26), the liquid collection chamber (19) is composed of transverse grooves and longitudinal grooves, and is arranged crosswise, a backflow liquid inlet (a) is opened on the liquid collection chamber (19), and an opening (a) is opened on the steam collection chamber (26). There is a steam outlet (b); there are steam channels (23) and steam channels (24) on the upper cover (21), the steam channels (23) are composed of longitudinal channels, and the steam channels (24) communicate with the steam channels (23) and the steam collecting chamber (26); the capillary core (22) is placed between the liquid collecting chamber (19) and the steam channel (23). 4. The CPL system with planar capillary evaporator and condenser according to claim 1 or 2, characterized in that: the structure of the planar capillary evaporator (1) includes a base (33), The upper cover (28), the capillary core (36), the base (33) and the upper cover (28) are fixed and sealed; the separator (31) separates the upper cover (28) into a liquid collection chamber (30), a steam collection chamber Cavity (32), the liquid collection chamber (30) is composed of transverse grooves and longitudinal grooves, and is arranged crosswise, there is a backflow liquid inlet (a) on the liquid collection chamber (30), and a return liquid inlet (a) on the steam collection chamber (32) A steam outlet (b) is provided; a steam channel (35) and a steam channel (34) are provided on the base (33), the steam channel (35) is composed of longitudinal channels, and the steam channel (34) communicates with the steam channel (35) and steam collecting cavity (32); Capillary core (36) is placed between liquid collecting cavity (30) and steam channel (35). 5. The CPL system with planar capillary evaporator and condenser according to claim 4, characterized in that: a cooling fin (29) is arranged on the outer surface of the upper cover (28). 6. The CPL system with planar capillary evaporator and condenser according to claim 1, characterized in that: the shape of the subcooler (4) is a coil. 7. The CPL system with planar capillary wick evaporator and condenser according to claim 1, characterized in that: the capillary wick is pressed by multi-layer wire mesh.

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