Passive cooling system

Abstract

The present invention relates to the technical field of cooling systems, and provides a passive cooling system comprising: a heat exchange device, a first pipeline, and a separation box; the heat exchange device is used to exchange heat with seawater, the heat exchange device is connected to the separation box, and the heated seawater enters the separation box; the first pipeline is connected to the separation box, and the first pipeline is used to discharge the heated seawater; a baffle is provided in the separation box, and the baffle is used to prevent steam bubbles from flowing along the first pipeline. The above-mentioned passive cooling system, by providing a baffle in the separation box, can use buoyancy and the baffle to separate the steam-water mixture, so that the steam gathers at the top of the separation box and the liquid gathers at the bottom of the separation box, thereby discharging the liquid from the first pipeline, avoiding direct contact between the steam in the first pipeline and the reflux supercooled seawater to cause condensation, thereby inducing water hammer.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling systems, and in particular to a passive cooling system. Background Art

[0002] In an offshore floating platform, the core continues to generate heat even after the reactor is shut down. This accumulated heat raises the temperature of its internal components, potentially causing meltdown of the fuel rod cladding, leading to radioactive material release and threatening personnel and equipment safety. To address this issue, offshore floating platforms are equipped with a passive cooling system connected to hot hydrazine seawater. During operation, the passive cooling system relies on the driving force generated by the density difference between the hot and cold fluids in the hot and cold pipes to circulate the coolant, thereby safely dissipating the residual heat from the core to the final hot hydrazine seawater. However, when the residual heat power of the core is high, the fluid in the hot pipe section of the passive cooling system undergoes a drastic phase change, resulting in a large amount of steam in the heat pipe connected to the seawater, forming a vapor plug. When the vapor plug in the hot pipe section comes into direct contact with the returning supercooled seawater, the steam rapidly condenses. The vapor plug collapses, causing water hammer in the heat pipe, generating large pressure pulsations and flow oscillations. This, in turn, compromises the structural integrity of the passive cooling system and reduces its heat transfer capacity, threatening the safety of the offshore floating platform.

[0003] There are currently two technical solutions to mitigate the water hammer phenomenon caused by steam condensation in passive cooling systems. One involves adding a knob-type tie device inside the pipe, which creates a turbulent flow through the pipe to prevent large steam bombs and eliminate water hammer. The other involves installing an orifice plate partition at the heat pipe outlet to suppress seawater backflow through the heat pipe. However, both of these solutions require additional condensation water hammer mitigation devices inside or at the heat pipe outlet. This additional device increases the flow resistance of the system circuit, reducing the heat transfer capacity of the passive cooling system and threatening the safety of offshore floating platforms. Summary of the Invention

[0004] The present invention provides a passive cooling system for solving the defect in the prior art that the flow resistance of the system loop is increased due to the addition of a condensate hammer elimination device.

[0005] The present invention provides a passive cooling system, comprising: a heat exchange device, a first pipeline, and a separation box; the heat exchange device is used to exchange heat with seawater, the heat exchange device is connected to the separation box, and the heated seawater enters the separation box; the first pipeline is connected to the separation box, and the first pipeline is used to discharge the heated seawater; a partition is provided in the separation box, and the partition is used to prevent steam bubbles from flowing along the first pipeline.

[0006] According to a passive cooling system provided by the present invention, the separation box is provided with a liquid inlet and a liquid outlet, the liquid inlet is connected to the heat exchange device, and the liquid outlet is connected to the first pipeline; the liquid inlet and the liquid outlet are located on both sides of the partition.

[0007] According to a passive cooling system provided by the present invention, the height of the partition is greater than the height of the liquid outlet.

[0008] According to a passive cooling system provided by the present invention, it also includes a second pipeline. The separation box is provided with a steam outlet, and the steam outlet is located above the liquid outlet. The second pipeline is connected to the steam outlet and is used to discharge steam.

[0009] A passive cooling system provided according to the present invention further includes a first valve, which is arranged in the first pipeline.

[0010] A passive cooling system provided according to the present invention further includes a second valve, which is arranged in the second pipeline.

[0011] A passive cooling system provided according to the present invention further includes a liquid level meter, which is arranged in the separation box.

[0012] A passive cooling system provided according to the present invention further includes a controller, which is used to control the opening and closing of the second valve according to the liquid level data detected by the liquid level meter.

[0013] According to a passive cooling system provided by the present invention, the heat exchange device includes: a heat exchanger and a third pipeline, the third pipeline is thermally coupled to the heat exchanger; the first end of the third pipeline is used to introduce seawater, and the second end of the third pipeline is connected to the separation box.

[0014] A passive cooling system provided according to the present invention further includes a third valve, which is arranged in the third pipeline.

[0015] The passive cooling system provided by the present invention, by arranging a baffle in the separation box, can use buoyancy and the baffle to separate the steam-water mixture, so that the steam gathers at the top of the separation box and the liquid gathers at the bottom of the separation box, thereby discharging the liquid through the first pipeline, avoiding direct contact between the steam in the first pipeline and the return supercooled seawater to cause condensation, thereby inducing water hammer; the passive cooling system provided by the present invention does not require additional structural parts, the system flow resistance is not significantly increased, and the heat transfer capacity is guaranteed while eliminating water hammer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of the passive cooling system provided by the present invention.

[0018] Reference numerals:

[0019] 10. Heat exchanger; 11. Heat exchange tube; 12. Third pipeline; 13. Third valve; 20. Separation box; 21. Partition; 30. First pipeline; 31. First valve; 40. Second pipeline; 41. Second valve; 50. Liquid level gauge. DETAILED DESCRIPTION

[0020] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0023] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0024] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0025] The following combination Figure 1 The passive cooling system of the present invention is described.

[0026] like Figure 1 As shown, in an embodiment of the present invention, the passive cooling system includes a heat exchange device, a separation tank 20, and a first pipeline 30. The heat exchange device is connected to the separation tank 20 and is used to exchange heat with seawater. The first pipeline 30 is connected to the separation tank 20 and is used to discharge the heated seawater. A baffle 21 is provided within the separation tank 20 to prevent steam bubbles from flowing along the first pipeline 30.

[0027] Specifically, under the heating action of the heat exchange device, the temperature of the fluid in the heat exchange device gradually increases and the density gradually decreases, resulting in a density difference between the fluid and the seawater. Under the action of the driving force generated by the density difference, the seawater enters the heat exchange device, and the seawater is heated by the heat exchange device. The heated seawater enters the separation box 20, and then flows through the first pipeline 30 into the ocean.

[0028] When the heat exchange rate in the heat exchanger exceeds a certain value, the seawater is heated to boiling, generating a large number of bubbles, forming a steam-water mixture containing a large number of steam bubbles. When the steam-water mixture enters the separation tank 20, the steam bubbles, due to buoyancy, gather at the top of the separation tank 20, forming a steam space, while the liquid phase fluid gathers at the bottom of the separation tank 20, forming a liquid space. A clear phase interface exists between the vapor and liquid. The steam bubbles rise under the action of buoyancy, but are blocked by the partition 21 during their rise, causing the steam bubbles to gather at the top of the separation tank 20 and not enter the first pipeline 30. The liquid is discharged from the first pipeline 30.

[0029] In this embodiment, by providing a partition 21, the steam-water mixture in the separation box 20 can be separated, and only saturated water is discharged into the ocean through the first pipeline 30, thereby fundamentally avoiding water hammer induced by direct contact and condensation between steam in the first pipeline 30 and the returning supercooled seawater.

[0030] The passive cooling system provided by the embodiment of the present invention, by providing a baffle in the separation box, can use buoyancy and the baffle to separate the steam-water mixture, so that the steam gathers at the top of the separation box and the liquid gathers at the bottom of the separation box, thereby discharging the liquid through the first pipeline, thereby avoiding direct contact between the steam in the first pipeline and the returning supercooled seawater to cause condensation, thereby inducing water hammer; the passive cooling system provided by the embodiment of the present invention does not require additional structural parts, the system flow resistance is not significantly increased, and the heat transfer capacity is guaranteed while eliminating water hammer.

[0031] In an embodiment of the present invention, the separation box 20 is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the heat exchange device, and the liquid outlet is connected to the first pipeline 30 . The liquid inlet and the liquid outlet are located on both sides of the partition 21 .

[0032] Specifically, under the heating action of the heat exchange device, the temperature of the fluid in the heat exchange device gradually increases and the density gradually decreases, resulting in a density difference between the fluid and the seawater. Under the driving force generated by the density difference, the seawater enters the heat exchange device, is heated by the heat exchange device, and the heated seawater enters the separation box 20 through the liquid inlet.

[0033] When the heat exchange rate in the heat exchange device exceeds a certain value, the seawater is heated to boiling, generating a large number of bubbles, forming a steam-water mixture containing a large number of steam bubbles. When the steam-water mixture enters the separation tank 20, the steam bubbles rise due to buoyancy. During this rise, the partition 21 blocks the steam bubbles, preventing them from flowing into the first pipeline 30 through the liquid outlet during the rise. This prevents the steam bubbles from condensing in the first pipeline 30 and causing water hammer.

[0034] Furthermore, in an embodiment of the present invention, the height of the partition 21 is greater than the height of the liquid outlet, so that steam bubbles can move upward along the partition 21 under the action of buoyancy, thereby forming a steam space at the top of the separation box 20, and the liquid can pass over the partition 21 and enter the first pipeline 30 from the liquid outlet, thereby discharging the heated seawater into the ocean.

[0035] like Figure 1 As shown, in an embodiment of the present invention, the passive cooling system further includes a second pipeline 40. The separation box 20 is provided with a steam outlet, which is located above the liquid outlet. The second pipeline 40 is connected to the steam outlet and is used to discharge steam.

[0036] Specifically, as the passive cooling system operates, more and more steam accumulates at the top of the separator box 20, and the liquid level in the separator box 20 gradually decreases. When the liquid level falls below the height of the partition 21, the liquid cannot be discharged through the first pipe 30. Therefore, before the liquid level in the separator box 20 drops below the partition 21, the second pipe 40 should be opened in time to discharge the steam in the separator box 20 through the second pipe 40, so that the liquid level in the separator box 20 can rise.

[0037] In the embodiment described above, the liquid inlet can be set on the bottom surface of the separation box 20 to facilitate the entry of seawater into the separation box 20 under the action of the driving force; the liquid outlet can be set on the side of the separation box 20, and the steam outlet can be set on the top surface of the separation box 20 to facilitate the discharge of steam.

[0038] like Figure 1 As shown, in an embodiment of the present invention, the heat exchange device includes: a heat exchanger 10 and a third pipeline 12, the third pipeline 12 is thermally coupled to the heat exchanger 10, a first end of the third pipeline 12 is used to introduce seawater, and a second end of the third pipeline 12 is connected to the separation box 20.

[0039] Specifically, heat exchanger 10 includes heat exchange tubes 11. Under the heating effect of heat exchanger 10, the temperature of the fluid in heat exchange tubes 11 gradually increases and the density gradually decreases. This creates a density difference between the fluid in heat exchange tubes 11 and the seawater. This density difference generates a driving force that forces the seawater to enter third pipeline 12. The seawater exchanges heat with the high-temperature fluid in heat exchange tubes 11, heating the seawater, which then enters separation tank 20.

[0040] like Figure 1 As shown, in an embodiment of the present invention, the passive cooling system further includes a first valve 31, a second valve 41, and a third valve 13. The first valve 31 is provided in the first pipeline 30 for controlling the on-off of the first pipeline 30. The second valve 41 is provided in the second pipeline 40 for controlling the on-off of the second pipeline 40. The third valve 13 is provided in the third pipeline 12 for controlling the on-off of the third pipeline 12.

[0041] Specifically, before the passive cooling system is put into operation, the first valve 31, the second valve 41, and the third valve 13 are all closed, isolating the first pipeline 30 and the third pipeline 12 from the seawater. After the passive cooling system is put into operation, the first valve 31 and the third valve 13 are opened. Seawater enters the third pipeline 12 due to the driving force generated by the density difference between the fluid and the seawater. The seawater exchanges heat with the high-temperature fluid in the heat exchange tube 11, heating the seawater, which then enters the separation tank 20.

[0042] When the heat exchange rate in heat exchanger 10 exceeds a certain value, the seawater is heated to boiling, generating a large number of bubbles and forming a steam-water mixture containing numerous steam bubbles. When the steam-water mixture enters separation tank 20, the steam bubbles, driven by buoyancy, gather at the top of separation tank 20, forming a vapor space. The liquid phase fluid gathers at the bottom of separation tank 20, forming a liquid space, with a distinct phase interface between the vapor and liquid. During this process, second valve 41 is closed, steam bubbles gather at the top of separation tank 20, and first valve 31 is open, allowing the liquid to be discharged into the ocean through first pipeline 30.

[0043] As more and more steam gathers at the top of the separation box 20, the liquid level in the separation box 20 gradually decreases. Before the liquid level in the separation box 20 drops below the partition 21, the second valve 41 is opened to discharge the steam in the separation box 20 through the second pipeline 40, so that the liquid level in the separation box 20 rises.

[0044] like Figure 1 As shown, in an embodiment of the present invention, the passive cooling system further includes a liquid level meter 50 . The liquid level meter 50 is disposed in the separation box 20 and is used to detect the liquid level of the liquid in the separation box 20 .

[0045] Furthermore, the passive cooling system further includes a controller, which is electrically connected to the liquid level meter 50 and the second valve 41 .

[0046] Specifically, the liquid level gauge 50 is used to monitor the liquid level in the separation tank 20 in real time. When the liquid level reaches a first preset value, that is, when the liquid level is about to reach the top of the partition 21, the liquid level gauge 50 sends a signal to the controller, which controls the second valve 41 to open, thereby venting the steam. When the liquid level returns to a second preset value, the controller controls the second valve 41 to close. In this embodiment, the first preset value is a lower liquid level, and the second preset value is a higher liquid level.

[0047] It is understandable that the first preset value and the second preset value can be flexibly set according to the specific heights of the separation box 20 and the partition 21, so that the controller can automatically control the second valve 41 to be opened or closed.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A passive cooling system, characterized in that: It includes: a heat exchange device, a first pipeline and a separation box; The heat exchange device is used to exchange heat with seawater, and the heat exchange device is connected to the separation box, and the heated seawater enters the separation box; The first pipeline is connected to the separation box, and the first pipeline is used to discharge the heated seawater; A partition is provided in the separation box, and the partition is used to prevent steam bubbles from flowing along the first pipeline.

2. The passive cooling system according to claim 1, characterized in that: The separation box is provided with a liquid inlet and a liquid outlet, the liquid inlet is communicated with the heat exchange device, and the liquid outlet is communicated with the first pipeline; The liquid inlet and the liquid outlet are located on both sides of the partition.

3. The passive cooling system according to claim 2, characterized in that: The height of the partition is greater than the height of the liquid outlet.

4. The passive cooling system according to claim 2, wherein: It also includes a second pipeline, the separation box is provided with a steam outlet, and the steam outlet is located above the liquid outlet; The second pipeline is connected to the steam outlet, and the second pipeline is used to discharge steam.

5. The passive cooling system according to claim 1, wherein: The system further includes a first valve, which is disposed in the first pipeline.

6. The passive cooling system according to claim 4, characterized in that The system further includes a second valve, which is disposed in the second pipeline.

7. The passive cooling system according to claim 6, characterized in that: It also includes a liquid level meter, which is arranged on the separation box.

8. The passive cooling system according to claim 7, characterized in that: It also includes a controller, which is used to control the opening and closing of the second valve according to the liquid level data detected by the liquid level meter.

9. The passive cooling system according to claim 1, wherein: The heat exchange device comprises: a heat exchanger and a third pipeline, wherein the third pipeline is thermally coupled to the heat exchanger; The first end of the third pipeline is used for introducing seawater, and the second end of the third pipeline is communicated with the separation box.

10. The passive cooling system according to claim 9, characterized in that: It also includes a third valve, which is arranged in the third pipeline.

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