Boiling heat exchange device suitable for long pipeline and using method of boiling heat exchange device

Abstract

The invention discloses a boiling heat exchange device suitable for a long pipeline and a using method of the boiling heat exchange device, and belongs to the technical field of boiling heat exchange equipment. The device comprises an outer sleeve and a plurality of limiting pipelines annularly arranged along the inner wall of the outer sleeve, and an inner cavity of each limiting pipeline is divided into a plurality of limiting spaces communicating with one another; a liquid storage part is arranged in the limiting space and comprises a shell and a hollow cavity defined by the shell; wherein a plurality of micropores are formed in the shell, and the liquid storage component sucks liquid through the micropores in the surface and stores the liquid in the hollow cavity. The liquid storage component firstly moves in the limiting space under the pushing of a liquid phase or a gas phase; then, the liquid stored in the hollow cavity is separated from the liquid storage component through the micropores, part of the separated liquid is used for wetting the pipe wall, and part of the separated liquid is transferred to the next limiting space; therefore, on-way segmented liquid supplementing and rewetting are achieved, attenuation of the heat exchange capacity of a high-dryness section is relieved, and the heat exchange stability is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of boiling heat exchange equipment, and more specifically, relates to a boiling heat exchange device suitable for long pipelines and its usage method. Background Technology

[0002] In key equipment such as large steam pipelines and main feedwater pipelines in nuclear power plants and thermal power plants, there are often ultra-long transmission pipelines, some hundreds of meters long, which operate under high temperature and high pressure conditions for extended periods. Due to the continuous accumulation of heat absorbed along the pipeline, the flow state and phase of the working fluid inside the pipeline dynamically evolve with the transmission distance, leading to a gradual decrease in the heat transfer capacity of the pipeline along its length.

[0003] The reasons for this are twofold. First, once the liquid inside the pipe enters the boiling stage, the formation, growth, and detachment of bubbles become unstable, easily leading to bubble coalescing into large bubbles. Simultaneously, in high-dryness pipe sections, the phenomenon of gas film obstruction between the pipe wall and the liquid working medium is more likely to occur, directly resulting in a significant increase in heat transfer resistance and a marked decrease in pipeline heat exchange efficiency. Second, during long-term operation, the inner wall of the pipeline is prone to the adhesion and scaling of media deposits, forming additional heat transfer resistance and further weakening the overall heat exchange performance of the pipeline. This also adversely affects the operational stability of the entire power system. Therefore, effectively improving the heat transfer capacity along the pipeline of ultra-long transport lines, ensuring heat exchange efficiency, and maintaining stable system operation are of significant practical importance in production.

[0004] A search revealed a patent in CN119412983A, which discloses an enhanced boiling heat exchange device for particulate fluids. This application includes a cooling channel, particles, and a cooling medium. The cooling channel has a cold surface and a hot surface. The particles and cooling medium can flow within the cooling channel. The particles include a shell and a core, with the core located within the shell. A cavity exists between the shell and the core, communicating with an external cooling medium. Temperature changes between the cold and hot surfaces cause bubbles to form or collapse within the cavity, thereby altering the particle density and enabling the particles to oscillate between the cold and hot surfaces. This application utilizes temperature changes to generate or collapse bubbles within the cavity. Bubble generation reduces particle density while increasing buoyancy, while bubble collapse increases particle density, thus promoting oscillating motion between the cold and hot surfaces. While this application effectively improves heat transfer efficiency, in high-dryness sections, if the rewetting and replenishment intensity resulting from particle oscillation is insufficient to offset the evaporation loss due to wall phase change, localized drying may still occur, affecting heat transfer stability and the enhanced effect.

[0005] For example, patent CN113776377A discloses a boiling-enhanced evaporation heat exchange tube and its manufacturing apparatus and method. In this application, on the one hand, the constantly moving perturbed sphere, impacted by the fluid, continuously disperses bubbles, preventing their aggregation and formation of a gas film, thus generating film boiling and reducing the thermal resistance inside the tube. Simultaneously, as the fluid passes through the perturbed sphere, a Karman vortex street effect is formed, increasing fluid turbulence and improving the fluid field cooperation, effectively enhancing heat transfer. On the other hand, by gradually increasing surface wettability from the perturbed sphere to the traction line, the surface roughness gradually decreases. This allows the droplets to obtain the Laplace pressure difference driving force to move from the perturbed sphere to the inner wall of the tube via the traction line, achieving anti-gravity directional transport of the droplets. This provides more liquid to the wall surface, promoting wall liquid replenishment, enhancing the wettability of the boiling surface, and regulating the phase distribution inside the tube, thereby enhancing the boiling heat transfer coefficient. However, the fixed local disturbance pattern in this application may be insufficient to support continuous fluid replenishment and rewetting in the high-dryness zone later, making it difficult to form a stable segmented fluid supply and cross-segment redistribution mechanism. At the same time, its disturbance mode and mechanism of action are relatively fixed, which may limit its adaptability to different operating conditions along the process. Summary of the Invention

[0006] The problem to be solved

[0007] In view of at least some of the problems existing in the prior art, the present invention proposes a boiling heat exchange device and its usage method suitable for long pipelines, the purpose of which is to alleviate the problems of reduced heat exchange capacity and insufficient wall wetting in the high dryness section along the long pipeline.

[0008] Technical solution To solve the above problems, the technical solution adopted by the present invention is as follows: The present invention provides a boiling heat exchange device suitable for long pipelines, comprising an outer sleeve, wherein the inner wall of the outer sleeve is provided with a plurality of limiting pipes extending axially along the outer sleeve. The limiting pipe is a hollow structure, and its inner cavity is divided into several interconnected limiting spaces. The confined space is equipped with a liquid storage component, which includes a shell and a hollow cavity enclosed by the shell; wherein, The shell has several micropores, and the liquid storage component draws in liquid through the micropores on its surface and stores it in the hollow cavity. The liquid storage component moves within the confined space under the impetus of the liquid or gas phase; subsequently, the liquid stored in the hollow cavity detaches from the liquid storage component through micropores, and part of the detached liquid is used to wet the tube wall, while part is transferred to the next confined space.

[0009] In some embodiments, the limiting pipe is provided with a plurality of partition plates along its axial direction, the partition plates dividing the inner cavity of the limiting pipe into a plurality of limiting spaces, and the partition plates are provided with through holes. The liquid storage component moves within a confined space under the impetus of the liquid or gas phase and collides with the partition plate to achieve the transfer and redistribution of liquid within the hollow cavity of the liquid storage component.

[0010] In some embodiments, the axial dimension L2 of the limiting space is 4 to 12 times the axial dimension L1 of the liquid storage component.

[0011] In some embodiments, the radial dimension D1 of the liquid storage component is 0.80 to 0.98 times the radial dimension D2 of the limiting space.

[0012] In some embodiments, the pore size of the micropores is 50~300 μm.

[0013] In some implementations, the spacing between two adjacent limiting pipes is 2.3 to 2.6 times the radius of the limiting pipe.

[0014] In some embodiments, the outer sleeve is provided with an inner sleeve; wherein, The inner sleeve has a hollow structure, and the limiting pipe is clamped in the annular channel formed between the inner and outer sleeves.

[0015] In some embodiments, the liquid storage component is a spherical or cylindrical structure.

[0016] In some embodiments, the partition plate is a sintered metal plate; the thermal conductivity of the liquid storage component is not less than 150 W / (m·K).

[0017] The above-described method for using a boiling heat exchanger suitable for long pipelines has the following workflow: First, the fluid in the pipe flows along the pipe in the form of a single liquid phase and is heated by the pipe wall. The micropores and pore structure on the surface of the liquid storage component can provide more nucleation sites, and the system enters the two-phase flow stage of nucleation boiling in advance. At the same time, the micropores can draw in and store some liquid into the hollow cavity of the liquid storage component under capillary action; Then, as the two phases develop to the point where the gas phase content increases, the liquid storage component continues to roll under the impetus of the fluid and gas phases and collides with and shears the bubbles, causing the large bubbles to break down into smaller bubbles again in order to maintain the heat exchange capacity of the two phases. Then, the fluid continues to absorb heat along the way, the gas phase content gradually increases, and the liquid phase content on the wall gradually decreases, eventually developing into a continuous gas film coverage. At this time, the tube enters the film boiling stage, which makes the wall and the liquid separated by the gas film, making it difficult for the liquid to directly wet the wall and increasing the heat transfer resistance. As the liquid storage component moves forward, it collides with the partition plate, causing the liquid inside the storage component to be ejected through micropores. Some of the ejected liquid is directly replenished to the vicinity of the wall for rapid rewetting, while the other part enters the next limiting space through the through-holes on the partition plate, forming segmented liquid replenishment and redistribution along the process.

[0018] Beneficial effects Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The boiling heat exchange device of the present invention, applicable to long pipelines, through the setting of porous liquid storage components and limiting pipes, can enable the pipeline to enter the high-efficiency heat exchange state dominated by nucleation boiling earlier, shortening the inefficient single-phase relative flow section. At the same time, it can break up the large bubbles that have been formed, maintaining a strong two-phase heat exchange capacity. On the other hand, the liquid storage component throws the stored water out through micropores, realizing rapid rewetting of the wall surface; at the same time, part of the thrown-out stored water can enter the next limiting space, forming segmented liquid replenishment and redistribution along the pipeline, thereby effectively alleviating the problem of decreased heat exchange capacity and insufficient wall wetting in the high dryness section along the long pipeline, making the film boiling last longer and cover a longer range along the pipeline. Furthermore, the continuous rolling of the liquid storage component in the limiting space will generate a certain friction with the wall surface, which can weaken the adhesion and accumulation tendency of deposits on the wall surface, reduce the additional thermal resistance caused by scaling, and help maintain the heat exchange performance and system stability during long-term operation.

[0019] (2) A boiling heat exchange device suitable for long pipes according to the present invention can physically divide the inner cavity of the limiting pipe by setting a partition plate to form multiple relatively independent limiting spaces. At the same time, the setting of the partition plate can provide collision objects for the liquid storage component to better throw out the stored liquid for transfer and redistribution; on the other hand, the partition plate can provide multiple stable support points for the limiting pipe, thereby effectively preventing the hollow limiting pipe from bending and deforming.

[0020] (3) The boiling heat exchange device of the present invention is suitable for long pipelines. By precisely controlling the axial and radial dimensions of the limiting space and the liquid storage component, it can ensure that the liquid storage component has sufficient movement stroke in the limiting space to adsorb and store as much liquid as possible. On the other hand, it can also ensure that the liquid storage component can effectively collide with the downstream partition plate under the push of the liquid phase or gas phase to throw out the liquid.

[0021] (4) The boiling heat exchange device of the present invention is suitable for long pipelines. By controlling the pore size of the micropores on the surface of the liquid storage component, it can take into account the liquid absorption capacity, liquid storage stability and liquid release response under collision action to a certain extent, thereby facilitating continuous liquid replenishment and rewetting.

[0022] (5) A boiling heat exchange device suitable for long pipes according to the present invention has an inner sleeve inside the outer sleeve, and the limiting pipe is clamped in the annular channel formed between the inner and outer sleeves, thereby further ensuring the stability of the limiting pipe. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of a boiling heat exchange device suitable for long pipelines according to the present invention; Figure 2 This is a schematic diagram of the internal structure of a boiling heat exchanger suitable for long pipelines according to the present invention. Figure 3 This is a schematic diagram of the internal structure of the limiting pipe in this invention; Figure 4 This is a schematic diagram of the structure of a single limiting space in this invention; Figure 5 This is one structural form of the liquid storage component in this invention; Figure 6 This is another structural form of the liquid storage component in this invention; Figure 7 This is a comparison diagram of gas-liquid two-phase flow in a pipe equipped with the boiling heat exchange device of the present invention and a regular pipe.

[0024] In the diagram: 100, outer sleeve; 200, inner sleeve; 300, annular channel; 400. Limiting pipe; 410. Limiting space; 420. Partition plate; 421. Through hole; 500, Liquid storage component; 510, Micropore. Detailed Implementation

[0025] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] The present invention will be further described below with reference to specific embodiments.

[0028] like Figure 2As shown, a boiling heat exchange device suitable for long pipelines according to this embodiment includes an outer casing 100, a limiting pipe 400, and a liquid storage component 500. Multiple limiting pipes 400 are arranged circumferentially along the inner wall of the outer casing 100, and the extension direction of each limiting pipe 400 is circumferential to the outer casing 100.

[0029] Meanwhile, the inner cavity of the limiting pipe 400 is divided into several interconnected limiting spaces 410, and each limiting space 410 is equipped with a liquid storage component 500.

[0030] Specifically, refer to Figure 3 , Figure 4 , Figure 5 As shown, the liquid storage component 500 includes a shell and a hollow cavity enclosed by the shell. The shell has a plurality of micropores 510, through which the liquid storage component 500 draws in liquid and stores it in the hollow cavity.

[0031] The limiting conduit 400 is provided with a plurality of partition plates 420 along its axial direction, which divide the inner cavity of the limiting conduit 400 into a plurality of limiting spaces 410. The partition plates 420 are provided with through holes 421 so that adjacent limiting spaces 410 can communicate with each other.

[0032] In this embodiment, the partition plate 420 provides a collision target for the liquid storage component 500, facilitating the transfer and redistribution of the stored liquid. Furthermore, the partition plate 420 provides multiple stable support points for the limiting pipe 400, effectively preventing the hollow limiting pipe 400 from bending or deforming.

[0033] Furthermore, the limiting pipe 400 is an overall hollow cylindrical structure, so that in the liquid single-phase section, the liquid can be immersed into the limiting space 410 and cover the liquid storage component 500, thereby providing conditions for the liquid storage component 500 to adsorb and store the liquid.

[0034] During operation, the liquid storage component 500 moves within the limiting space 410 under the influence of the liquid or gas phase and collides with the partition plate 420. This causes the liquid stored in the hollow cavity to detach from the liquid storage component 500 through the micropores 510. Part of the detached liquid is used to wet the tube wall, and part is transferred to the next limiting space 410, thereby realizing the transfer and redistribution of the liquid.

[0035] This embodiment provides a boiling heat exchange device suitable for long pipelines. Through the cooperation of the porous liquid storage component 500 and the limiting pipe 400, the micropores 510 and pore structure on the surface of the liquid storage component 500 can provide dense nucleation sites, making it easier for bubbles to form near the wall and establish a stable growth, enlargement and detachment process. This allows the pipeline to enter a highly efficient heat exchange state dominated by nucleation boiling earlier, shortening the inefficient single-phase flow section.

[0036] On the other hand, during the two-phase development process, when the bubbles coalesce and grow, the liquid storage component 500 rolls under the impetus of the fluid and vapor phases and collides with and shears the bubbles, which can break up the large bubbles that have been formed and maintain a strong two-phase heat exchange capacity.

[0037] On the other hand, when the pipeline enters the membrane boiling stage, the liquid storage component 500 absorbs water through the micropores 510 and stores water in the water storage chamber. Under the action of rolling impact on the partition plate 420, the stored water is thrown out through the micropores 510, realizing rapid rewetting of the wall surface. At the same time, some of the released water can cross the through hole 421 and enter the next limiting space 410, forming segmented liquid replenishment and redistribution along the pipeline, so that the membrane boiling can last longer and cover a longer range along the pipeline.

[0038] In addition, the continuous rolling of the liquid storage component 500 in the confined space 410 will generate a certain friction with the wall surface, which can weaken the tendency of deposits to adhere and accumulate on the wall surface, reduce the additional thermal resistance caused by scaling, and also help maintain the heat exchange performance and system stability during long-term operation.

[0039] refer to Figure 1 As shown, in some embodiments, an inner sleeve 200 is provided inside the outer sleeve 100, so that an annular channel 300 is formed between the inner and outer sleeves. The aforementioned limiting pipe 400 can be clamped and installed in the annular channel 300; at the same time, in conjunction with the segmented support effect of the partition plate 420, the stability of the limiting pipe 400 can be ensured.

[0040] Of course, the inner sleeve 200 also has a hollow structure to ensure that the fluid in the annular channel 300 remains connected in both the radial and circumferential directions, so that in the single-phase liquid section, the liquid can fill each limiting pipe 400.

[0041] Preferably, the partition plate 420 can be made of sintered metal plate or composite material plate to improve its temperature and pressure resistance and structural rigidity, and reduce the risk of bending and displacement of the hollow structure limiting pipe 400 under ultra-long working conditions.

[0042] Furthermore, the thermal conductivity of the liquid storage component 500 is not less than 150 W / (m·K). This is because when the thermal conductivity of the liquid storage component 500 is lower than this threshold, the internal temperature change of the liquid storage component 500 during heating and liquid release is relatively lagging, which can easily lead to uneven surface temperature distribution or increased local thermal resistance of the liquid storage component 500, thereby potentially reducing the efficiency of nucleation, liquid replenishment evaporation and rewetting cycles, and affecting the stability of enhanced heat transfer.

[0043] refer to Figure 5 , Figure 6 As shown, in some embodiments, the liquid storage component 500 may be a spherical structure, a cylindrical structure, or other shapes, and is not specifically limited herein.

[0044] However, the applicant's research found that, compared to spherical structures, cylindrical structures have a larger surface area and better axial guidance. The hollow body and porous skeleton can hold and carry more liquid, forming a longer near-wall replenishment area during movement and achieving continuous replenishment along the near-wall area. This is more conducive to improving the continuity and volume of replenishment along the pipe, thereby further improving the wetting conditions and heat exchange stability of high dryness pipe sections.

[0045] This embodiment provides a boiling heat exchange device suitable for long pipelines. As its working principle shows, the liquid storage component 500 needs to both adsorb and store the liquid, and stably carry the stored liquid before efficiently ejecting it upon impact. To simultaneously achieve these two effects, the pore size of the micropores 510 on the surface of the liquid storage component 500 needs to be strictly controlled.

[0046] If the pore size of the micropore 510 is too small, it will not only significantly reduce the efficiency of liquid penetration into the hollow cavity, making it difficult to quickly and effectively store liquid within the cavity, but also cause the liquid to be unable to break through the constraints of the micropore 510 and achieve efficient desorption after collision due to the excessively strong capillary force and liquid-solid bonding force within the micropore 510, thus greatly reducing the amount of liquid that can be ejected.

[0047] If the pore size of the micropore 510 is too large, its capillary adsorption force will be greatly reduced. Although the liquid can quickly enter the hollow cavity, it cannot remain stably in the cavity and is very likely to leak out in large quantities along the micropore 510 without collision, resulting in a significant decrease in the effective liquid storage capacity and ultimately seriously affecting the liquid storage.

[0048] Therefore, in this embodiment, to balance efficient liquid penetration into the reservoir 500 cavity, stable liquid retention within the cavity, and efficient desorption and ejection of liquid after collision, the pore size of the micropore 510 is controlled within the range of 50~300 μm. For example, 60 μm, 110 μm, 170 μm, 220 μm, 280 μm, etc.

[0049] In this embodiment, a boiling heat exchange device suitable for long pipes is provided. After the aperture of the micropore 510 is determined, in order to ensure that the liquid storage component 500 can throw more liquid towards the pipe wall and the next limiting space 410 after the collision, the hollow cavity of the limiting space 410 needs to carry as much liquid as possible.

[0050] To allow the hollow cavity to store more liquid, the liquid storage component 500 needs sufficient movement path within the limiting space 410 to provide a longer liquid absorption time. In other words, the limiting space 410 needs to have sufficient length (radial dimension). However, if the limiting space 410 is too long, the collision force between the liquid storage component 500 and the partition plate 420 will be too small, or even nonexistent, due to liquid resistance, which will affect the amount of liquid ejected from the liquid storage component 500.

[0051] Therefore, in this embodiment, the axial and radial dimensions of the limiting space 410 and the liquid storage component 500 are precisely controlled to balance the high liquid storage capacity of the liquid storage component 500 and the high amount of liquid shedding after collision.

[0052] Specifically, refer to Figure 4 As shown, in this embodiment, the axial dimension L2 of the limiting space 410 is 4 to 12 times the axial dimension L1 of the liquid storage component 500, for example, 6 times, 8 times, 10 times, etc.

[0053] The purpose of this design is to balance the amount of liquid absorbed by the liquid storage component 500 and the amount of liquid ejected after the liquid storage component 500 collides with it; on the other hand, it can prevent the liquid storage component 500 from bouncing back onto the previous partition plate 420 after colliding with the next partition plate 420 and colliding with it, thereby causing the reverse transfer of liquid.

[0054] It is worth mentioning that in this embodiment, the liquid in the liquid storage component 500 is mainly transported to the next limiting space 410 to prolong the gas single-phase flow stage. Therefore, the reverse transfer of liquid is obviously not conducive to the goal of delaying the gas single-phase flow stage.

[0055] Meanwhile, the radial dimension D1 of the liquid storage component 500 is 0.80 to 0.98 times the radial dimension D2 of the limiting space 410. For example, 0.85 times, 0.90 times, 0.95 times, etc. The purpose of this design is that, on the one hand, a certain space needs to be left between the liquid storage component 500 and the pipe wall of the limiting pipe 400 to prevent excessive friction from affecting the normal movement of the liquid storage component 500; on the other hand, if the gap between the two is too large, the mainstream will be more likely to bypass, the contact effect and periodic collision effect of the liquid storage component 500 on the near-wall area will be weakened, and the reduced volume of the liquid storage component 500 will lead to a decrease in liquid storage capacity and liquid carrying capacity, which is not conducive to forming a continuous and stable liquid replenishment and rewetting effect.

[0056] Furthermore, the applicant's research revealed that when the limiting pipes 400 are arranged too densely, the gaps between adjacent channels decrease, restricting the flow cross-section for fluid communication and distribution. This can easily lead to a limited flow cross-section, increased frictional resistance, and reduced local two-phase flow stability. This effect may be more pronounced under conditions such as deposition and scaling or thermal deformation. Conversely, when the limiting pipes 400 are arranged too sparsely, the number of separating channels decreases, limiting the coverage area of ​​the liquid storage component 500 and weakening the circumferential distribution and regulation capabilities of the liquid, potentially affecting the frictional enhancement effect.

[0057] Therefore, in this embodiment, the spacing between two adjacent limiting pipes 400 is 2.3 to 2.6 times the radius of the limiting pipe 400, in order to balance the arrangement density of the limiting pipes 400, fluid connectivity, and operating resistance.

[0058] refer to Figure 7 As shown, the liquid flows from left to right; (a) is a schematic diagram of gas-liquid two-phase flow in a normal pipe; (b) is a schematic diagram of two-phase flow in a pipe equipped with a boiling heat exchanger suitable for long pipes according to the above embodiment.

[0059] Depend on Figure 7 As can be seen in (a) of the diagram, in a typical ultra-long pipe, the fluid initially flows along the pipe in a single-phase liquid form and is heated by the pipe wall; as the fluid continues to absorb heat, the temperature gradually increases. When the fluid flows to a certain pipe section, although the mainstream liquid has not yet reached the saturation temperature and is still in a supercooled state, small bubbles will first appear on the wall surface due to the higher wall temperature.

[0060] As heating continues and the mainstream gradually reaches saturation temperature, the tube enters the nucleation boiling stage. At this point, bubbles continuously form, grow, and detach from the wall surface, leading to a continuous increase in gas phase content and improved heat transfer capacity. As the gas phase content further increases, bubbles coalesce to form large bubbles, resulting in a two-phase flow state characterized by large bubble boiling.

[0061] As the dryness continues to increase and the liquid content on the wall gradually decreases, dry spots will appear on the wall and develop into a continuous gas film, forming a film boiling state. At this point, the wall and the liquid are separated by the gas film, increasing the thermal resistance and decreasing the heat transfer capacity.

[0062] As the proportion of gas phase continues to increase, the liquid is gradually vaporized and exhausted, and the downstream section of the pipeline eventually transforms into a single-phase gas flow, thus completing the evolution process along the pipeline from single-phase liquid flow → nucleus boiling → large bubble boiling → film boiling → single-phase gas flow.

[0063] Depend on Figure 7 As can be seen from (b) above, in ultra-long pipelines using the device of this embodiment, The fluid initially flows along the pipe in a single-phase liquid form and is heated by the pipe wall. The micropores 510 and pore structure on the surface of the liquid storage component 500 provide more nucleation sites, making it easier to generate more bubbles. Therefore, under the same conditions, compared with ordinary pipes, continuous bubble generation and detachment occur earlier along the pipe, and the system enters the two-phase flow stage of nucleation boiling earlier.

[0064] When the two phases develop to the point where the gas phase content increases, bubbles in ordinary pipes tend to coalesce into large bubbles. However, in this embodiment, the liquid storage component 500 continuously rolls under the impetus of the fluid and vapor phases and collides with and shears the bubbles, which can impact the already coalesced large bubbles and break them back into smaller bubbles, thus helping to maintain a strong two-phase heat exchange capacity.

[0065] As the fluid continues to absorb heat along the path and the gas content gradually increases, the liquid content on the wall gradually decreases and eventually develops into a continuous gas film coverage, and the tube enters the film boiling stage; at this time, the wall and the liquid are separated by the gas film, and the liquid cannot directly wet the wall, increasing the heat transfer resistance.

[0066] In this embodiment, the liquid storage component 500 is used to store, release, and redistribute water. Its surface micropores 510 can draw in and store some water into the internal water storage chamber under capillary action; at the same time, the liquid storage component 500 rolls forward axially under the joint push of the fluid and vapor phases and collides with the through-hole partition plate 420. After the collision, it briefly rebounds and retreats, and is then pushed towards the partition plate 420 again by the fluid and repeats the collision.

[0067] Through the aforementioned periodic impact process, the liquid storage component 500, under the combined action of inertia and pressure difference, flings the water in the storage chamber out through the micropores 510. A portion of this water directly replenishes the vicinity of the wall surface for rapid rewetting, while the remaining water enters the next limiting space 410 through the through-holes 421 on the partition plate 420, forming segmented liquid replenishment and redistribution along the process. Through this process, the liquid from the preceding section can be transported to the following section, continuously providing liquid replenishment support for the high dryness region, thereby enabling film boiling to continue for a longer period and cover a wider area along the process.

[0068] Of course, as the heat absorption of the fluid along the flow path further increases until the liquid is essentially vaporized and exhausted, the system will still enter the gas single-phase flow stage. However, due to the aforementioned enhancement and rewetting effects, the location of the gas single-phase flow usually shifts later and the transition is smoother. Overall, this results in an extended effective heat transfer zone for two-phase boiling, more uniform heat transfer along the flow path, and smaller flow and temperature fluctuations, thereby achieving higher heat transfer efficiency in the process of evolution from liquid single-phase to two-phase boiling and then to gas single-phase.

[0069] During the single-phase gas flow stage, the liquid storage component 500 can still roll and impact the partition plate 420 under the impetus of the vapor flow, and can intermittently release water to achieve local rewetting of the wall surface. At the same time, its rolling friction helps to inhibit the adhesion of deposits, thereby reducing wall temperature fluctuations and maintaining long-term operational stability.

[0070] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A boiling heat exchanger suitable for long pipes, comprising an outer casing (100), characterized in that: The inner wall of the outer sleeve (100) is provided with a plurality of limiting pipes (400) extending axially along the outer sleeve (100). The limiting pipe (400) is a hollow structure, and the inner cavity of the limiting pipe (400) is divided into several interconnected limiting spaces (410). The limiting space (410) is provided with a liquid storage component (500), the liquid storage component (500) including a shell and a hollow cavity enclosed by the shell; wherein, The shell has a plurality of micropores (510), and the liquid storage component (500) draws in liquid through the micropores (510) on its surface and stores it in the hollow cavity; The liquid storage component (500) moves within the limiting space (410) under the impetus of the liquid or gas phase; then, the liquid stored in the hollow cavity leaves the liquid storage component (500) through the micropores (510), and part of the detached liquid is used to wet the tube wall, and part is transferred to the next limiting space (410).

2. The boiling heat exchanger suitable for long pipelines according to claim 1, characterized in that: The limiting pipe (400) is provided with a plurality of partition plates (420) along its axial direction. The partition plates (420) divide the inner cavity of the limiting pipe (400) into a plurality of limiting spaces (410), and the partition plates (420) are provided with through holes (421). The liquid storage component (500) moves within the limiting space (410) under the push of the liquid or gas phase and collides with the partition plate (420) to realize the transfer and redistribution of liquid in the hollow cavity of the liquid storage component (500).

3. A boiling heat exchanger suitable for long pipelines according to claim 2, characterized in that: The axial dimension L2 of the limiting space (410) is 4 to 12 times the axial dimension L1 of the liquid storage component (500).

4. A boiling heat exchanger suitable for long pipelines according to claim 3, characterized in that: The radial dimension D1 of the liquid storage component (500) is 0.80 to 0.98 times the radial dimension D2 of the limiting space (410).

5. A boiling heat exchanger suitable for long pipelines according to any one of claims 1 to 4, characterized in that: The pore size of the micropore (510) is 50~300 μm.

6. A boiling heat exchanger suitable for long pipelines according to claim 5, characterized in that: The distance between two adjacent limiting pipes (400) is 2.3 to 2.6 times the radius of the limiting pipe (400).

7. A boiling heat exchanger suitable for long pipelines according to claim 1, characterized in that: The outer sleeve (100) is provided with an inner sleeve (200); wherein, The inner sleeve (200) is a hollow structure, and the limiting pipe (400) is clamped in the annular channel (300) formed between the inner and outer sleeves.

8. A boiling heat exchanger suitable for long pipelines according to claim 7, characterized in that: The liquid storage component (500) has a spherical or cylindrical structure.

9. A boiling heat exchanger suitable for long pipelines according to claim 7 or 8, characterized in that: The partition plate (420) is a sintered metal plate; the thermal conductivity of the liquid storage component (500) is not less than 150 W / (m·K).

10. A method of using a boiling heat exchanger suitable for long pipes as described in any one of claims 1 to 9, characterized in that: Its workflow is as follows: First, the fluid in the pipe flows along the pipe in the form of a single liquid phase and is heated by the pipe wall. The micropores (510) and pore structure on the surface of the liquid storage component (500) can provide more nucleation sites, and the system enters the two-phase flow stage of nucleation boiling in advance. At the same time, the micropores (510) can draw in and store a portion of the liquid into the hollow cavity of the liquid storage component (500) under capillary action; Then, as the two phases develop to the point where the gas phase content increases, the liquid storage component (500) continues to roll under the impetus of the fluid and gas phases and collides with and shears the bubbles, causing the large bubbles to break down into smaller bubbles again in order to maintain the heat exchange capacity of the two phases. Then, the fluid continues to absorb heat along the way, the gas phase content gradually increases, and the liquid phase content on the wall gradually decreases, eventually developing into a continuous gas film coverage. At this time, the tube enters the film boiling stage, which makes the wall and the liquid separated by the gas film, making it difficult for the liquid to directly wet the wall and increasing the heat transfer resistance. As the liquid storage component (500) moves forward, it collides with the partition plate (420) and throws the liquid in the liquid storage component (500) out through the micropores (510). Among them, part of the liquid thrown out is directly replenished to the vicinity of the wall to achieve rapid rewetting, and the other part enters the next limiting space (410) through the through hole (421) on the partition plate (420), forming segmented liquid replenishment and redistribution along the process.

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