Vapor-liquid two-phase flow generation system for reactor core heat exchange research

Abstract

The invention provides a vapor-liquid two-phase flow generation system for reactor core heat exchange research, comprising: a vapor-water mixer having a first inlet, a second inlet and a first outlet; the steam generator is used for producing steam; the saturated water heater is used for producing saturated water, the saturated water heater is provided with a saturated water inlet and a saturated water outlet, the saturated water outlet is communicated with an inlet of the second pipeline, and an outlet of the second pipeline is communicated with the saturated water inlet through a water return pipeline; an outlet of the second pipeline is communicated with a second inlet of the steam-water mixer through a third pipeline, a water pump is arranged on the second pipeline, a water return on-off valve is arranged on the water return pipeline, and a third on-off valve is arranged on the third pipeline. Therefore, the vapor-liquid two-phase flow generation system for the heat exchange research of the reactor core has the advantages of convenience in accurate and reliable control and long-term stable operation.

Description

Technical Field

[0001] The invention relates to the technical field of vapor-liquid two-phase generation, and in particular to a vapor-liquid two-phase flow generation system for reactor core heat exchange research. Background Art

[0002] A loss of coolant accident is an accident in which the pressure boundary pipe of the reactor coolant system is damaged. It is one of the most important design basis accidents of light water reactor nuclear power plants. A large break is defined as a total break cross-sectional area greater than or equal to 0.09m 2 For the AP series reactor type, a large rupture is a Class IV accident (limit accident), which is not expected to occur during the entire life of the nuclear power plant, but it is still conservatively assumed to be a design basis accident. When a large rupture accident occurs, the evolution of the core can be divided into the following three stages: the blowdown stage, the refilling stage, and the reflooding stage. The reactor undergoes a series of complex thermal hydraulic processes during this process. The post-CHF heat exchange phenomenon of the core during the blowdown and refilling stages of the large rupture accident is a key phenomenon in the reactor. It is necessary to conduct in-depth research through experiments to explore the heat exchange mechanism, obtain the heat exchange relationship, and provide data support for software development and verification. During the blowdown and refilling stages, the core fluid is in a saturated vapor-liquid two-phase flow state. In order to accurately reproduce the core heat exchange phenomenon at this stage, it is necessary to provide vapor-liquid two-phase injection boundary conditions for the test section. The vapor-liquid two-phase flow generation system of the reactor core heat exchange research in the related technology is unstable, and it is difficult to conduct experiments for a long time. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention provides a vapor-liquid two-phase flow generation system for reactor core heat exchange research, comprising:

[0005] a soda mixer having a first inlet, a second inlet, and a first outlet;

[0006] A steam generator, the steam generator is used to produce steam, the steam generator has a first water replenishment port and a steam outlet, the steam generated by the steam generator can be discharged from the steam outlet, the steam outlet is connected to the first inlet through a first pipeline, and the temperature of the steam discharged from the steam outlet is a first preset value;

[0007] A saturated water heater, the saturated water heater is used to produce saturated water, the saturated water heater has a saturated water inlet and a saturated water outlet, the saturated water outlet is connected to the inlet of the second pipeline, the outlet of the second pipeline is connected to the saturated water inlet through a return pipeline, the outlet of the second pipeline is connected to the second inlet of the soda-water mixer through a third pipeline, a water pump is provided on the second pipeline, a return water on-off valve is provided on the return pipeline, a third on-off valve is provided on the third pipeline, and the temperature of the saturated water discharged from the saturated water outlet is less than or equal to a second preset value;

[0008] Among them, when the return water on-off valve is closed and the third on-off valve is opened, the temperature of the saturated water discharged from the saturated water outlet is the second preset value, the second preset value is less than the first preset value, and a heating device is provided on the first pipeline, and the heating device is used to heat the steam in the first pipeline so that the steam temperature in the first pipeline is a third preset value, and the third preset value is greater than the first preset value.

[0009] Therefore, the vapor-liquid two-phase flow generation system for reactor core heat exchange research according to the embodiment of the present invention has the advantages of being easy to accurately and reliably control and operating stably for a long time.

[0010] In some embodiments, when the return water on-off valve is closed and the third on-off valve is opened, the temperature of the saturated water discharged from the saturated water outlet is 3° C. to 8° C. lower than the temperature of the steam discharged from the steam outlet;

[0011] After being heated by the heating device, the temperature of the steam in the first pipeline is 3° C. to 8° C. higher than the temperature of the steam discharged from the steam outlet.

[0012] In some embodiments, when the return water on-off valve is closed and the third on-off valve is opened, the temperature of the saturated water discharged from the saturated water outlet is 5° C. lower than the temperature of the steam discharged from the steam outlet;

[0013] After being heated by the heating device, the temperature of the steam in the first pipeline is 5° C. higher than the temperature of the steam discharged from the steam outlet.

[0014] In some embodiments, the first preset value is greater than or equal to 275° C. and less than or equal to 295° C.;

[0015] The second preset value is greater than or equal to 270° C. and less than or equal to 290° C.;

[0016] The third preset value is greater than or equal to 280° C. and less than or equal to 300° C.

[0017] In some embodiments, a first opening and closing valve, a first regulating valve and a first flow meter are provided on the first pipeline, and the first regulating valve is used to regulate the flow of the first pipeline;

[0018] The second pipeline is provided with a second opening and closing valve and the water pump;

[0019] The third pipeline is provided with the third opening and closing valve, the second regulating valve and the second flow meter, and the second regulating valve is used for regulating the flow of the third pipeline.

[0020] In some embodiments, the outlet of the soda mixer is connected to a fourth pipeline, the outlet of the fourth pipeline is connected to a test section pipeline, a wire mesh sensor is provided in the fourth pipeline, and a fourth opening and closing valve is provided on the fourth pipeline.

[0021] In some embodiments, the top of the saturated water heater is provided with a pressure stabilizing port, the pressure stabilizing port is connected to the nitrogen cylinder group through a fifth pipeline, and a fifth opening and closing valve is provided on the fifth pipeline.

[0022] In some embodiments, the steam generator is used to produce saturated steam, and the steam pressure discharged from the steam outlet of the steam generator is greater than or equal to 6 MPa and less than or equal to 8 MPa;

[0023] The steam generator is an electrically heated steam generator, and the exhaust steam flow rate of the steam outlet of the steam generator is greater than or equal to 2t / h.

[0024] In some embodiments, the pressure of the saturated water discharged from the saturated water outlet is greater than or equal to 6 MPa and less than or equal to 8 MPa;

[0025] The water return pipeline is provided with a water replenishment inlet, and the water replenishment inlet is communicated with the water replenishment pipeline.

[0026] In some embodiments, the heating device is a heating tape, and the heating tape is disposed on the first pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a vapor-liquid two-phase flow generation system for reactor core heat exchange research according to an embodiment of the present invention.

[0028] Reference numerals:

[0029] 1. soda mixer, 11. first inlet, 12. second inlet, 13. first outlet;

[0030] 2. steam generator, 21. steam outlet, 22. first pipeline, 23. first opening and closing valve, 24. first regulating valve;

[0031] 3. saturated water heater, 31. saturated water inlet, 32. saturated water outlet, 33. second pipeline, 331. second on-off valve, 34. return water pipeline, 341. return water on-off valve, 35. third pipeline, 351. third on-off valve, 36. second regulating valve, 37. water pump;

[0032] 4. fourth pipeline, 41. wire mesh sensor, 42. fourth opening and closing valve;

[0033] 5. Nitrogen cylinder group, 51. Fifth opening and closing valve, 52. Fifth pipeline. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] The following describes a vapor-liquid two-phase flow generation system for reactor core heat exchange research according to an embodiment of the present invention with reference to the accompanying drawings. Figure 1 As shown, the steam-liquid two-phase flow generating system for reactor core heat exchange research according to an embodiment of the present invention includes a steam-water mixer 1, a steam generator 2 and a saturated water heater 3.

[0036] The soda mixer 1 has a first inlet 11, a second inlet 12 and a first outlet 13. The first inlet 11 is used to introduce steam, and the second inlet 12 is used to introduce saturated water. The steam and saturated water are mixed in the soda mixer 1 (and reach the parameters required for the test) and then discharged from the first outlet 13.

[0037] The steam generator 2 is used to produce steam. The steam generator 2 has a first water replenishment port (not shown in the figure) and a steam outlet 21. The first water replenishment port is used to replenish water into the steam generator 2. The steam generated by the steam generator 2 can be discharged from the steam outlet 21. The steam outlet 21 is connected to the first inlet 11 through the first pipeline 22. The temperature of the steam discharged from the steam outlet 21 is a first preset value.

[0038] The saturated water heater 3 is used to produce saturated water. The saturated water heater 3 has a saturated water inlet 31 and a saturated water outlet 32. The saturated water outlet 32 ​​is connected to the inlet of the second pipeline 33, and the outlet of the second pipeline 33 is connected to the saturated water inlet 31 through the return pipeline 34. The outlet of the second pipeline 33 is connected to the second inlet 12 of the soda mixer 1 through the third pipeline 35. A water pump 37 is provided on the second pipeline 33, a return water on-off valve 341 is provided on the return pipeline 34, and a third on-off valve 351 is provided on the third pipeline 35. The temperature of the saturated water discharged from the saturated water outlet 32 ​​is less than or equal to the second preset value. A water replenishment inlet is provided on the return pipeline 34, and the water replenishment inlet is connected to the water replenishment pipeline. The water replenishment pipeline can replenish water into the return pipeline 34 through the water replenishment inlet, so as to replenish water into the saturated water heater 3.

[0039] Specifically, the second preset value is a temperature value that satisfies the temperature of the water entering the soda mixer 1. When the temperature of the saturated water produced by the saturated water heater 3 does not meet the requirement, that is, when the temperature of the saturated water discharged from the saturated water outlet 32 ​​is less than the second preset value, the return water on-off valve 341 is opened and the third on-off valve 351 is closed, so that the water discharged from the saturated water outlet 32 ​​passes through the second pipeline 33 and the return water pipeline 34 and enters the saturated water heater 3 again, so that the water can be circulated and heated. After the temperature of the saturated water in the second pipeline 33 meets the requirement, that is, when the temperature of the saturated water discharged from the saturated water outlet 32 ​​is the second preset value, the return water on-off valve 341 is closed and the third on-off valve 351 is opened, so that the saturated water discharged from the saturated water outlet 32 ​​can enter the soda mixer 1. For example, the saturated water heater 3 is an electric heating device, and the heating power of the saturated water heater 3 is 250kW.

[0040] When the return water on-off valve 341 is closed and the third on-off valve 351 is opened, the temperature of the saturated water discharged from the saturated water outlet 32 ​​is a second preset value, and the second preset value is less than the first preset value. Specifically, when the return water on-off valve 341 is closed and the third on-off valve 351 is opened, the temperature of the saturated water discharged from the saturated water outlet 32 ​​and passed into the soda mixer 1 is a second preset value.

[0041] A heating device is provided on the first pipeline 22, and the heating device is used to heat the steam in the first pipeline 22 so that the temperature of the steam in the first pipeline 22 is a third preset value, and the third preset value is greater than the first preset value.

[0042] In the related art, the temperatures of the output saturated water and steam are the same, and the steam will condense on the transport pipeline during the transport process, while the saturated water will vaporize before the pump in the pipeline.

[0043] The temperature of the steam discharged from the steam outlet 21 of the steam-liquid two-phase flow generation system for reactor core heat exchange research according to the embodiment of the present invention is a first preset value, and the first preset value is the temperature value of the steam and saturated water originally designed. The temperature of the saturated water discharged from the saturated water outlet 32 ​​is controlled to be less than or equal to the second preset value, and the second preset value is less than the first preset value, so that the temperature of the saturated water in the second pipeline 33, the return water pipeline 34 and the third pipeline 35 can be lower, thereby reducing the saturated water vaporization at the pump body (water pump 39) on the second pipeline 33, the return water pipeline 34 and the third pipeline 35 and the related delivery pipelines.

[0044] A heating device is provided on the first pipeline 22 so that the steam temperature in the first pipeline 22 is a third preset value greater than the first preset value, that is, the steam temperature in the first pipeline 22 is higher, thereby reducing the condensation of the steam in the first pipeline 22 and related transmission pipelines to produce droplets, thereby reducing pipeline damage. By increasing the temperature of the steam being transmitted and reducing the saturated water temperature, the long-term operation of the pipeline, valves and pump equipment can be facilitated, thereby improving the safety and life of the system, so as to facilitate long-term testing.

[0045] In some embodiments, when the return water on-off valve 341 is closed and the third on-off valve 351 is opened (i.e., when the saturated water discharged from the saturated water outlet 32 ​​needs to be passed into the soda mixer 1), the temperature of the saturated water discharged from the saturated water outlet 32 ​​is 3°C to 8°C lower than the temperature of the steam discharged from the steam outlet 21. Specifically, when the return water on-off valve 341 is closed and the third on-off valve 351 is opened, the temperature of the saturated water discharged from the saturated water outlet 32 ​​is 3°C to 8°C lower than the first preset value (design value), that is, the second preset value is 3°C to 8°C lower than the first preset value. For example, when the return water on-off valve 341 is closed and the third on-off valve 351 is opened, the temperature of the saturated water discharged from the saturated water outlet 32 ​​is 5°C lower than the temperature of the steam discharged from the steam outlet 21.

[0046] In some embodiments, the temperature of the steam in the first pipeline 22 after heating by the heating device is 3°C to 8°C higher than the temperature of the steam discharged from the steam outlet 21. Specifically, the temperature of the steam in the first pipeline 22 after heating by the heating device is 3°C to 8°C higher than the first preset value, that is, the third preset value is 3°C to 8°C higher than the first preset value. For example, the temperature of the steam in the first pipeline 22 after heating by the heating device is 5°C higher than the temperature of the steam discharged from the steam outlet 21.

[0047] In some embodiments, the first preset value is greater than or equal to 275°C and less than or equal to 295°C, that is, the temperature of the steam discharged from the steam outlet 21 is greater than or equal to 275°C and less than or equal to 295°C. The second preset value is greater than or equal to 270°C and less than or equal to 290°C, that is, the temperature of the saturated water discharged from the saturated water outlet 32 ​​and entering the soda-water mixer 1 is greater than or equal to 270°C and less than or equal to 290°C. The third preset value is greater than or equal to 280°C and less than or equal to 300°C, that is, the temperature of the steam in the first pipeline 22 after heating by the heating device is greater than or equal to 280°C and less than or equal to 300°C. For example, the temperature of the steam discharged from the steam outlet 21 is 280°C, the temperature of the saturated water discharged from the saturated water outlet 32 ​​and entering the soda-water mixer 1 is 275°C, and the temperature of the steam in the first pipeline 22 after heating by the heating device is 285°C.

[0048] In some embodiments, the heating device is a heating belt (not shown in the figure), and the heating belt is arranged on the first pipeline 22. Specifically, the heating belt is an electric heating device to heat the steam in the first pipeline 22.

[0049] The steam generator 2 is used to produce saturated steam. The steam pressure discharged from the steam outlet 21 of the steam generator 2 is greater than or equal to 6Mpa and less than or equal to 8Mpa; the pressure of saturated water discharged from the saturated water outlet 32 ​​is greater than or equal to 6Mpa and less than or equal to 8Mpa. For example, the steam pressure discharged from the steam outlet 21 of the steam generator 2 and the pressure of saturated water discharged from the saturated water outlet 32 ​​are both 6.5Mpa, 7Mpa, 7.5Mpa or 8Mpa. The steam generator 2 is an electrically heated steam generator 2, and the exhaust flow rate of the steam outlet 21 of the steam generator 2 is greater than or equal to 2t / h (tons / hour).

[0050] like Figure 1 As shown, in some embodiments, a first opening and closing valve 23, a first regulating valve 24 and a first flow meter (not shown in the figure) are provided on the first pipeline 22, and the first regulating valve 24 is used to adjust the flow of the first pipeline 22. Thus, the first pipeline 22 can be opened by the first opening and closing valve 23, the first flow meter is used to measure the flow of the first pipeline 22, and the steam flow entering the steam-water mixer 1 is adjusted by the first regulating valve 24.

[0051] The second pipeline 33 is provided with a second on-off valve 331 and a water pump 37. The third pipeline 35 is provided with a third on-off valve 351, a second regulating valve 36 and a second flow meter (not shown in the figure), and the second regulating valve 36 is used to adjust the flow of the third pipeline 35. Specifically, the inlets of the return water pipeline 34 and the third pipeline 35 are both connected to the outlet of the second pipeline 33. After the second on-off valve 331 and the return water on-off valve 341 are opened and the third on-off valve 351 is closed, the water in the second pipeline 33 can enter the return water pipeline 34 to provide circulating water for the saturated water heater 3. After the second on-off valve 331 and the third on-off valve 351 are opened and the return water on-off valve 341 is closed, the saturated water can enter the steam-water mixer 1. The second flow meter is used to measure the flow on the third pipeline 35. The second regulating valve 36 can adjust the flow of the saturated water entering the steam-water mixer 1, thereby realizing accurate and reliable control of the steam and saturated water.

[0052] like Figure 1 As shown, in some embodiments, the outlet of the soda mixer 1 is connected to the fourth pipeline 4, the outlet of the fourth pipeline 4 is connected to the test section pipeline, a wire mesh sensor 41 is provided in the fourth pipeline 4, and a fourth on-off valve 42 is provided on the fourth pipeline 4. Specifically, the wire mesh sensor 41 is a sensor for measuring the flow characteristics of the multiphase flow (gas-liquid two-phase flow) in the fourth pipeline 4, and the wire mesh sensor 41 is used to confirm the state of the mixed soda-water mixture, and the relevant equipment or parameters can be adjusted through the data transmitted by the wire mesh sensor 41. After the fourth on-off valve 42 is opened, the soda-water mixture discharged from the soda mixer 1 can be injected into the test section through the fourth pipeline 4.

[0053] like Figure 1 As shown, in some embodiments, the top of the saturated water heater 3 is provided with a pressure stabilizing port, which is connected to the nitrogen cylinder group 5 through a fifth pipeline 52, and a fifth opening and closing valve 51 is provided on the fifth pipeline 52. The nitrogen cylinder group 5 can pass nitrogen into the saturated water heater 3 to stabilize the pressure in the saturated water heater 3.

[0054] The present invention generates saturated water and saturated steam separately and then mixes them, so that the pressure and flow rate of steam and water can be controlled separately, and the test parameters such as two-phase flow rate and steam content provided are more accurate, which can provide more stable boundary conditions for the core heat exchange test, and the test data obtained is of higher quality. A special nitrogen pressure stabilization system (nitrogen bottle group 5) is set on the saturated water heater 3, so that the pressure before the pump is more stable and the control of the saturated water flow rate is more stable. The saturated water heater is also provided with a circulating heating pipeline (return water pipeline 34) to ensure that the fluid is heated more evenly. A wire mesh sensor 41 is set at the outlet of the steam-water mixer 1 to monitor and confirm the flow state and flow type of the steam-liquid mixture to ensure that the two phases injected into the test section are evenly mixed. Therefore, the steam-liquid two-phase flow generation system for reactor core heat exchange research according to the embodiment of the present invention has the advantages of being easy to accurately and reliably control and long-term stable operation.

[0055] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in 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 obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0059] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. 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 present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0060] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A vapor-liquid two-phase flow generation system for reactor core heat exchange research, characterized in that: include: a soda mixer having a first inlet, a second inlet, and a first outlet; A steam generator, the steam generator is used to produce steam, the steam generator has a first water replenishment port and a steam outlet, the steam generated by the steam generator can be discharged from the steam outlet, the steam outlet is connected to the first inlet through a first pipeline, and the temperature of the steam discharged from the steam outlet is a first preset value; A saturated water heater, the saturated water heater is used to produce saturated water, the saturated water heater has a saturated water inlet and a saturated water outlet, the saturated water outlet is connected to the inlet of the second pipeline, the outlet of the second pipeline is connected to the saturated water inlet through a return pipeline, the outlet of the second pipeline is connected to the second inlet of the soda-water mixer through a third pipeline, a water pump is provided on the second pipeline, a return water on-off valve is provided on the return pipeline, a third on-off valve is provided on the third pipeline, and the temperature of the saturated water discharged from the saturated water outlet is less than or equal to a second preset value; Among them, when the return water on-off valve is closed and the third on-off valve is opened, the temperature of the saturated water discharged from the saturated water outlet is the second preset value, the second preset value is less than the first preset value, and a heating device is provided on the first pipeline, and the heating device is used to heat the steam in the first pipeline so that the steam temperature in the first pipeline is a third preset value, and the third preset value is greater than the first preset value.

2. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 1, characterized in that: When the return water on-off valve is closed and the third on-off valve is opened, the temperature of the saturated water discharged from the saturated water outlet is 3°C to 8°C lower than the temperature of the steam discharged from the steam outlet; After being heated by the heating device, the temperature of the steam in the first pipeline is 3° C. to 8° C. higher than the temperature of the steam discharged from the steam outlet.

3. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 2, characterized in that: When the return water on-off valve is closed and the third on-off valve is opened, the temperature of the saturated water discharged from the saturated water outlet is 5°C lower than the temperature of the steam discharged from the steam outlet; After being heated by the heating device, the temperature of the steam in the first pipeline is 5° C. higher than the temperature of the steam discharged from the steam outlet.

4. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 1, characterized in that: The first preset value is greater than or equal to 275° C. and less than or equal to 295° C.; The second preset value is greater than or equal to 270° C. and less than or equal to 290° C.; The third preset value is greater than or equal to 280° C. and less than or equal to 300° C.

5. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 3, characterized in that: The first pipeline is provided with a first opening and closing valve, a first regulating valve and a first flow meter, and the first regulating valve is used to regulate the flow of the first pipeline; The second pipeline is provided with a second opening and closing valve and the water pump; The third pipeline is provided with the third opening and closing valve, the second regulating valve and the second flow meter, and the second regulating valve is used for regulating the flow of the third pipeline.

6. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 5, characterized in that: The outlet of the soda-water mixer is communicated with a fourth pipeline, the outlet of the fourth pipeline is communicated with a test section pipeline, a wire mesh sensor is arranged in the fourth pipeline, and a fourth opening and closing valve is arranged on the fourth pipeline.

7. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 5, characterized in that: The top of the saturated water heater is provided with a pressure stabilizing port, the pressure stabilizing port is connected to the nitrogen cylinder group through a fifth pipeline, and a fifth opening and closing valve is provided on the fifth pipeline.

8. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 5, characterized in that: The steam generator is used to produce saturated steam, and the steam pressure discharged from the steam outlet of the steam generator is greater than or equal to 6Mpa and less than or equal to 8Mpa; The steam generator is an electrically heated steam generator, and the exhaust steam flow rate of the steam outlet of the steam generator is greater than or equal to 2t / h.

9. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to claim 5, characterized in that: The pressure of the saturated water discharged from the saturated water outlet is greater than or equal to 6 MPa and less than or equal to 8 MPa; The water return pipeline is provided with a water replenishment inlet, and the water replenishment inlet is communicated with the water replenishment pipeline.

10. The vapor-liquid two-phase flow generation system for reactor core heat exchange research according to any one of claims 1 to 9, characterized in that: The heating device is a heating belt, and the heating belt is arranged on the first pipeline.

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