An inflation heat exchange plate and method suitable for high temperature subcooled boiling gas-liquid two-phase flow

Abstract

The application provides an inflation heat exchange plate suitable for high-temperature subcooled boiling gas-liquid two-phase flow and an implementation method thereof, which comprises an inlet pipe, a weld, an inflation diffusion zone and an outlet pipe, the inflation diffusion zone is composed of a plurality of welds and inflation diffusion flow channels, and is sequentially divided into a subcooled preheating zone, a saturated boiling zone and a high dryness zone from the inlet to the outlet, two heat exchange plates with the same shape and size are welded on four edges to form a weld for sealing, the inflation diffusion zone inside is a fluid heat exchange zone, and the plurality of welds are arranged at intervals with the inflation diffusion flow channels. The inlet pipe and the outlet pipe are connected with the heat exchange plates through welding, the inlet pipe is connected with the subcooled preheating zone, and the outlet pipe is connected with the high dryness zone. The number of the inlet pipe and the outlet pipe can be one or more, and the pipe diameter of the inlet pipe and the outlet pipe is greater than the hydraulic diameter of the inflation diffusion channel, so that the stability of the subcooled boiling gas-liquid two-phase flow is enhanced while the heat exchange is considered.

Description

Technical Field

[0001] This invention relates to the field of heat exchange technology, and in particular to a blown heat exchange plate and method suitable for high-temperature subcooled boiling gas-liquid two-phase flow. Background Technology

[0002] Supercooled boiling is a localized boiling phenomenon that occurs near a heated surface when a liquid is at a temperature below its saturation temperature. It is widely found in industrial equipment such as nuclear reactors, heat exchangers, and boilers. Compared to single-phase heat transfer, although supercooled boiling can significantly improve heat transfer efficiency, its complex gas-liquid two-phase flow characteristics can easily lead to instability, seriously affecting the performance and operational safety of the equipment.

[0003] During supercooled boiling, bubbles are generated, grow, detach, and migrate with the fluid on the heated surface. Because bubble formation is accompanied by rapid changes in local pressure and temperature, it can cause fluid oscillations and flow instabilities, leading to system thermal oscillations and even malfunctions. In extreme cases, localized overheating caused by bubbles can lead to material failure of the heat exchange surface or equipment meltdown. Supercooled boiling also exacerbates corrosion of the heated surface, deteriorates heat exchange performance, and threatens the safety and reliability of industrial heat exchange equipment.

[0004] Chinese patent CN103585795A discloses an experimental system for eliminating supercooled boiling bubbles generated in a preheater. The bubble elimination tank is arranged between the preheater and the experimental device. Although the system can efficiently eliminate supercooled boiling bubbles generated in the preheater, the system has many components, which increases the complexity of the system.

[0005] In existing technologies, mitigating the effects of subcooled boiling by optimizing the flow channel design and operating parameters of heat exchangers has become a research hotspot. Shortening the pipe diameter of the subcooled boiling section is a common way to reduce subcooled boiling oscillations. Under small pipe diameter conditions, the fluid flow diffusion is large, and due to the enhanced turbulence effect, the fluid temperature uniformity is high, making it less likely for subcooled boiling condensation vibrations to form, thus suppressing the instability of subcooled boiling.

[0006] Blow-blown heat exchange plates are a type of highly efficient heat exchange equipment. The unique corrugated structure formed by the blowing process increases the heat exchange area and enhances the heat exchange capacity of the internal fluid. However, the blowing height of blow-blown heat exchange plates currently on the market is uniform, making it difficult to suppress subcooled boiling instability, which poses a significant challenge to the safety of the heat exchange system. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned problems and to provide a blown heat exchange plate and method suitable for high-temperature subcooled boiling gas-liquid two-phase flow.

[0008] Firstly, a blown heat exchange plate suitable for high-temperature subcooled boiling gas-liquid two-phase flow is provided, comprising an inlet pipe, a weld, a blown diffusion zone, and an outlet pipe. The blown diffusion zone consists of several weld points and blown diffusion channels, and is divided into a subcooled preheating zone, a saturated boiling zone, and a high dryness zone from the inlet to the outlet.

[0009] Two identical heat exchange plates are welded together on all four sides to form a seal. The interior is a blown-diffusion zone for fluid heat exchange, with several weld points spaced apart from the blown-diffusion channels. The inlet and outlet pipes are connected to the heat exchange plates by welding. The inlet pipe connects to the subcooled preheating zone, and the outlet pipe connects to the high dryness zone. There can be one or more inlet and outlet pipes, and their diameters must be larger than the hydraulic diameter of the blown-diffusion channels.

[0010] The solder joints on the heat exchange plates are arranged in an alternating equilateral triangle pattern. In the subcooled preheating zone, the solder joint spacing is 0.5 to 2.0 times the solder joint diameter. In the saturated boiling zone and high dryness zone, the solder joint spacing is 2 to 5 times and 1.2 to 3 times that of the subcooled preheating zone, respectively. The height of the blown diffusion channel includes both non-uniform height distribution characteristics formed under the same blown pressure and blown time stress characteristics, and defined uniform height characteristics formed under the same blown pressure and blown time stress characteristics. For the former type of height distribution characteristic, in this example, the blown diffusion channel at both ends is lower, and the blown diffusion channel in the middle is higher.

[0011] A method for implementing a blown heat exchange plate based on high-temperature subcooled boiling gas-liquid two-phase flow is applicable when high-temperature heat storage generates high-temperature steam, and the wall surface of the blown heat exchange plate is under conditions of high superheat. The method specifically includes the following steps:

[0012] Water first enters the subcooled preheating zone through the inlet pipe. Due to the small equivalent pipe diameter of the flow channel in the subcooled preheating zone and the large flow diffusion, as well as the enhanced turbulence effect, the fluid temperature uniformity is high, making it difficult to form subcooled boiling condensation vibration phenomenon and suppressing the instability of subcooled boiling.

[0013] Water then enters the saturated boiling zone from the subcooled preheating zone. Due to the large equivalent pipe diameter of the flow channel in the saturated boiling zone, the inertial effect of the flow is reduced, the system's flow fluctuation is decreased, and the gas-liquid distribution within the zone is improved, reducing bubble aggregation and local overheating, thus improving the stability of the flow.

[0014] As the steam-water mixture moves from the saturated boiling zone into the high dryness zone, the number of weld points increases, enhancing the turbulence effect on the fluid and strengthening the convective heat transfer of the droplet-containing steam flow. At the same time, the large equivalent pipe diameter of the flow channel in the high dryness zone strengthens the separation of droplets and steam. The high-temperature steam with higher dryness finally flows from the high dryness zone to the outlet pipe, thus completing the entire heat exchange process.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention designs a blown heat exchange plate structure with variable flow channel height by optimizing the distribution of weld points and the blown height. The fluid instability under subcooled boiling conditions is reduced under low flow channel conditions. The structure from high flow channel to low flow channel enhances the heat exchange and steam-water separation of the fluid. This invention enhances the stability of subcooled boiling gas-liquid two-phase flow while also strengthening heat exchange.

[0017] This invention only requires consideration of changing the distribution of weld points in different areas during the design process. It does not require adding extra process steps or changing technical parameters such as blowing pressure to the traditional blown heat exchange plate manufacturing process, thus reducing the impact of subcooled boiling instability and improving flow stability.

[0018] Compared to traditional equipment and systems for collecting and removing supercooled boiling bubbles, this invention is simpler in system design, requires no additional equipment or instruments, reduces manufacturing costs, and lowers the overall cost of the heat exchange system. Attached Figure Description

[0019] Figure 1 This is a weld point distribution diagram suitable for blown plate heat exchangers used in subcooled boiling gas-liquid two-phase flow.

[0020] Figure 2 It is a cross-sectional view of a non-uniform height distribution flow channel formed under the stress characteristics of the same inflation pressure and inflation time;

[0021] Figure 3 It is a cross-sectional diagram of a flow channel with defined height characteristics formed under the same inflation pressure and inflation time.

[0022] Figure label:

[0023] 1. Inlet pipe; 2. Weld seam; 3. Blow-diffusion zone; 4. Outlet pipe; 5. Weld point; 6. Blow-diffusion flow channel; 7. Subcooled preheating zone; 8. Saturated boiling zone; 9. High dryness zone. Detailed Implementation

[0024] To facilitate understanding of the present invention, a more complete description of the invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be more thorough and complete.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "page," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," and "equipped" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Example

[0028] like Figure 1 As shown, a blown heat exchange plate suitable for high-temperature subcooled boiling gas-liquid two-phase flow includes an inlet pipe 1, a weld 2, a blown diffusion zone 3, an outlet pipe 4, a weld point 5, a blown diffusion channel 6, a subcooled preheating zone 7, a saturated boiling zone 8, and a high dryness zone 9.

[0029] Two identical heat exchange plates are welded together on all four sides to form a weld seam 2 for sealing. The interior is a blown diffusion zone 3 for fluid heat exchange, with several weld points 5 spaced apart from the blown flow channel 6. From inlet to outlet, the zone sequentially includes a subcooled preheating zone 7, a saturated boiling zone 8, and a high dryness zone 9. Inlet pipe 1 and outlet pipe 4 are connected to the heat exchange plates by welding. Inlet pipe 1 connects to the subcooled preheating zone 7, and outlet pipe 4 connects to the high dryness zone 9. There can be one or more inlet pipes 1 and outlet pipes 4, and the diameter of both inlet pipe 1 and outlet pipe 4 must be larger than the equivalent diameter of the blown channel 6.

[0030] The solder joints 5 on the heat exchange plates are arranged in an alternating equilateral triangle pattern. In the subcooled preheating zone 7, the solder joint spacing is 0.5 to 2.0 times the solder joint diameter. The solder joint spacing in the saturated boiling zone 8 and the high dryness zone 9 is 2 to 5 times and 1.2 to 3 times the solder joint spacing in the subcooled preheating zone 7, respectively.

[0031] like Figure 2 , Figure 3 The diagram shows cross-sectional views of the blown-diffusion channel under different stress characteristics. The height of the blown-diffusion channel 6 includes both the non-uniform height distribution characteristic formed under the same blowing pressure and blowing time, and the defined uniform height characteristic formed under the same blowing pressure and blowing time. For the former type of height distribution characteristic, in this example, the specific height is manifested as the blown-diffusion channels at both ends being lower and the blown-diffusion channels in the middle being higher; for the latter type of height characteristic, the height of the blown-diffusion channels remains consistent.

[0032] A method for implementing a blown heat exchanger plate based on high-temperature subcooled boiling gas-liquid two-phase flow is applicable when high-temperature heat storage generates high-temperature steam, and the wall surface of the blown heat exchanger plate is under conditions of high superheat. The specific steps are as follows:

[0033] Water first enters the subcooled preheating zone 7 through the inlet pipe 1. Due to the small equivalent pipe diameter of the flow channel in the subcooled preheating zone 7 and the large flow diffusion, as well as the enhanced turbulence effect, the fluid temperature uniformity is high, making it difficult to form subcooled boiling condensation vibration phenomenon and suppressing the instability of subcooled boiling.

[0034] Water then enters the saturated boiling zone 8 from the subcooled preheating zone 7. Due to the large equivalent pipe diameter of the flow channel in the saturated boiling zone 8, the inertial effect of the flow is reduced, the system's flow fluctuation is reduced, and the gas-liquid distribution inside the zone is improved, reducing bubble aggregation and local overheating, thus improving the stability of the flow.

[0035] The steam-water mixture enters the high dryness zone 9 from the saturated boiling zone 8. The number of welding points 5 increases, which enhances the turbulence effect on the fluid and strengthens the convective heat transfer of the vapor flow containing droplets. At the same time, the equivalent pipe diameter of the flow channel in the high dryness zone 9 is large, which strengthens the separation of droplets and steam. The high-temperature steam with higher dryness finally flows from the high dryness zone 9 to the outlet pipe 4, thus completing the entire heat exchange process.

[0036] The above-described embodiments are merely illustrative of certain implementations of the present invention, and are described in a relatively specific and detailed manner. However, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A blown heat exchange plate suitable for high-temperature subcooled boiling gas-liquid two-phase flow, characterized in that... It includes an inlet pipe (1), a weld (2), a blown diffusion zone (3) and an outlet pipe (4). The blown diffusion zone (3) consists of several weld points (5) and blown diffusion channels (6). From the inlet to the outlet, it is divided into a subcooled preheating zone (7), a saturated boiling zone (8), and a high dryness zone (9). Two heat exchange plates of identical shape and size are welded together on all four sides to form a weld (2) for sealing. The inside is a blown diffusion zone (3) for fluid heat exchange. Several weld points (5) are arranged alternately with the blown diffusion channel (6). The inlet pipe (1) and the outlet pipe (4) are connected to the heat exchange plates by welding. The inlet pipe (1) is connected to the subcooled preheating zone (7), and the outlet pipe (4) is connected to the high dryness zone (9). The solder joints (5) are arranged in an alternating equilateral triangle pattern. The spacing between solder joints in the supercooled preheating zone (7) is 0.5 to 2.0 times the solder joint diameter. The spacing between solder joints in the saturated boiling zone (8) and the high dryness zone (9) is 2 to 5 times and 1.2 to 3 times the spacing between solder joints in the supercooled preheating zone (7), respectively.

2. The blown heat exchange plate suitable for high-temperature subcooled boiling gas-liquid two-phase flow according to claim 1, characterized in that: The number of inlet pipe (1) and outlet pipe (4) can be one or more, and the diameter of inlet pipe (1) and outlet pipe (4) is greater than the equivalent diameter of the blow-diffusion channel (6).

3. The method for implementing a blown heat exchange plate suitable for high-temperature subcooled boiling gas-liquid two-phase flow according to claim 1, characterized in that: It is suitable for use when high-temperature heat storage generates high-temperature steam, and the walls of the blown heat exchange plate are under conditions of high superheat. The steps include: Water first enters the subcooled preheating zone (7) through the inlet pipe (1). Due to the small equivalent pipe diameter of the flow channel in the subcooled preheating zone (7) and the large flow diffusion, the fluid temperature uniformity is high due to the turbulence enhancement effect, making it difficult to form subcooled boiling condensation vibration phenomenon and suppressing the instability of subcooled boiling. Water then enters the saturated boiling zone (8) from the subcooled preheating zone (7). Due to the large equivalent pipe diameter of the flow channel in the saturated boiling zone (8), the inertial effect of the flow is reduced, the system’s flow fluctuation is reduced, the gas-liquid distribution inside the zone is improved, bubble aggregation and local overheating are reduced, and the flow stability is improved. The steam-water mixture enters the high dryness zone (9) from the saturated boiling zone (8). The number of weld points (5) increases, which enhances the turbulence effect on the fluid and strengthens the convective heat transfer of the vapor flow containing droplets. At the same time, the equivalent pipe diameter of the flow channel in the high dryness zone (9) is large, which strengthens the separation of droplets and steam. The high-temperature steam with higher dryness finally flows from the high dryness zone (9) to the outlet pipe (4), and finally completes the entire heat exchange process.

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