Device and method for testing flowing accelerated corrosion performance of high-temperature water vapor pipeline

Abstract

The invention belongs to the technical field of flow accelerated corrosion testing, and particularly discloses a high-temperature water vapor pipeline flow accelerated corrosion performance testing device and method, and the high-temperature water vapor pipeline flow accelerated corrosion performance testing device comprises a detachable testing section, a steam generator, a spraying system and a steam compressor. The steam compressor is connected with the outlet end of the test section and the steam generator and is used for pressurizing to form high-flow-rate steam flow. The spraying system is connected with the bottom of the steam generator, the nozzle is arranged on the pipeline, and liquid drops are introduced into steam flow to form gas-liquid two-phase flow. A DCPD measuring system is integrated in the test section, comprises a sample clamping assembly, an electrode penetrating assembly and a sensor assembly, and is used for clamping a sheet-shaped sample and measuring the corrosion performance. According to the invention, the actual service conditions of the secondary loop pipeline of the nuclear power plant in a high-temperature, high-pressure and gas-liquid two-phase impact environment can be accurately simulated, and meanwhile, the corrosion thinning rate of the material is monitored in real time by utilizing the DCPD measurement system integrated in the detachable test section, so that the hysteresis quality of a traditional offline measurement method is overcome, and the accuracy of experimental data is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flow-accelerated corrosion testing, and in particular, to a testing device for the flow-accelerated corrosion performance of high-temperature water vapor pipelines. Background Art

[0002] The secondary circuit pipelines in nuclear power plants, such as feedwater pipelines and drain pipelines, etc., usually adopt carbon steel materials. These pipelines operate in a corrosive environment of high temperature and pressure, and gas-liquid two-phase impact for a long time, and are extremely vulnerable to the influence of flow-accelerated corrosion (FAC), resulting in local thinning of the pipeline. If not discovered and processed in time, it may cause the pipeline to rupture, releasing a large amount of high-temperature steam or water, thus seriously affecting the safe operation of the nuclear power plant. Most of the existing flow-accelerated corrosion experimental devices adopt the form of pipeline loops or rotating discs, but they cannot truly simulate the change of the fluid flow pattern in the pipeline under high pressure and high flow rate. For example, although the patent with the publication number CN111562188A can simulate the erosion environment of high-pressure and high-flow-rate two-phase flow, it does not consider the influence of the change of the geometric structure in the actual pipeline on the flow field; while the patent with the publication number CN107167383A pressurizes after the gas-liquid two-phase mixing, resulting in the generation of condensed water in the steam, and the liquid phase content cannot be effectively controlled, and neither of them monitors and processes the liquid phase medium, and the temperature range is also relatively limited.

[0003] Most of the existing corrosion rate measurement methods adopt offline means, such as the weight loss method and the ultrasonic thickness measurement method, which have problems such as measurement lag and low experimental efficiency, lack the collection of dynamic data on material corrosion during service, and cannot effectively establish the correlation between the material failure process and environmental parameters. Although the direct current potential drop method (DCPD) is a high-precision method for measuring metal thinning rate, which can calculate the corrosion thinning rate in real time, and there are already patents applying it to the measurement of metal thinning in high-temperature and high-pressure environments, there is currently no special DCPD online measurement device for flow-accelerated corrosion experiments.

[0004] In view of this, it is necessary to propose a testing device and method for the flow-accelerated corrosion performance of high-temperature water vapor pipelines to solve or improve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a testing device and method for the flow-accelerated corrosion performance of high-temperature water vapor pipelines, to supplement and improve the existing experimental devices, systems and experimental methods, so as to more accurately simulate the actual working conditions, monitor the dynamic corrosion data, and effectively control the experimental conditions, thereby providing more reliable technical support for the corrosion research and safety assessment of the secondary circuit pipelines in nuclear power plants.

[0006] To achieve the above object, in one aspect, the present invention provides a test device for the flow-accelerated corrosion performance of high-temperature water vapor pipelines, including a detachable test section, a steam generator connected to the inlet end of the detachable test section, and the steam generator is used to pressurize the steam to form a high-velocity steam flow; one end of the spray system is connected to the bottom of the steam generator, and the other end is arranged on the pipeline from the steam generator to the detachable test section to form a nozzle, which is used to introduce droplets into the steam flow to form a gas-liquid two-phase flow; a DCPD measurement system is integrated in the detachable test section, and the DCPD measurement system includes a specimen clamping assembly, an electrode penetration assembly, and a DCPD sensor assembly. The specimen clamping assembly clamps a sheet specimen in the detachable test section and exposes it to the gas-liquid two-phase flow. The electrode penetration assembly penetrates the detachable test section and connects the sheet specimen and the DCPD sensor assembly through electrode wires.

[0007] In some alternative embodiments of the present invention, the DCPD measurement system includes a sheet test section housing, electrode wires, and the specimen clamping assembly, the electrode penetration assembly, and the DCPD sensor assembly; a plurality of sheet specimens are equidistantly arranged in the inner cavity of the sheet test section housing, and a pair of measurement electrodes are symmetrically arranged on both sides of each sheet specimen to form multiple independent DCPD measurement circuits.

[0008] In some alternative embodiments of the present invention, the electrode penetration assembly includes a penetrator housing, and the penetrator housing accommodates an electrode penetrator; a penetrator water-cooling jacket is sleeved outside the penetrator housing, and an insulating connector is connected between the inside and the electrode penetrator; one end of the penetrator housing is connected to the sheet test section housing through a second fixing flange, and the other end is sealed through a compression sleeve and a compression nut.

[0009] In some alternative embodiments of the present invention, the insulating connector includes a four-hole ceramic tube one, a four-hole ceramic tube two, and a fluororubber seal. The four-hole ceramic tube one is arranged in the penetrator housing for electrical insulation. The four-hole ceramic tube two is arranged in the compression sleeve and cooperates with the four-hole ceramic tube one to further isolate the electrode from the housing. The fluororubber seal is located between the four-hole ceramic tube one and the four-hole ceramic tube two to provide high-temperature sealing.

[0010] In some alternative embodiments of the present invention, the steam compressor includes a steam turbine and a canned motor. The inlet of the steam turbine is connected to the outlet end of the detachable test section, and the outlet of the canned motor is connected to the steam generator.

[0011] In some alternative embodiments of the present invention, the spray system includes a centrifugal pump, a spray flowmeter, an ultrasonic droplet generator, and a nozzle. The centrifugal pump is connected to the bottom of the steam generator; the ultrasonic droplet generator is connected to the nozzle through the spray flowmeter.

[0012] In some optional solutions of the present invention, a spray flow meter is connected to the pipeline from the steam generator to the detachable test section, and the spray flow meter is located upstream of the nozzle.

[0013] In some optional solutions of the present invention, a steam outlet is opened at the top of the steam generator, and a rotary vane steam-water separator and a corrugated steam dryer are arranged inside.

[0014] In some optional schemes of the present invention, a water chemistry control system is also connected to the bottom of the steam generator, and the water chemistry control system includes a liquid level sensor, a regenerative heat exchanger and a water chemistry loop control system. The liquid level sensor is arranged at the bottom and the middle of the steam generator, and the regenerative heat exchanger adjusts the circulating water temperature through an upper filling pipe and a downstream discharge pipe.

[0015] In another aspect, the present invention provides a method for testing the flow accelerated corrosion performance of a high-temperature water vapor pipeline. The high-temperature water vapor pipeline flow accelerated corrosion performance testing device according to any of the above items comprises the following steps:

[0016] S1. Generate high-temperature and high-pressure steam through a steam generating device;

[0017] S2, pressurizing the steam using a steam compressor to form high-flow steam;

[0018] S3, introducing the controlled droplets into the steam flow through the spray system to form a gas-liquid two-phase flow;

[0019] S4, introducing the gas-liquid two-phase flow into the detachable test section, and using the DCPD measurement system in the detachable test section to monitor the corrosion and thinning rate of the material in real time;

[0020] S5. Use water chemistry control system to ensure the stability and controllability of experimental conditions.

[0021] Furthermore, the steam compressor increases the upstream and downstream pressure difference of the test section by ≥0.2MPa through the steam turbine and the canned motor, thereby achieving high flow rate control of the steam in the pipeline.

[0022] Compared with the prior art, the present invention at least discloses the following beneficial effects:

[0023] Through the cooperation of a steam compressor and a spraying system, the present invention can accurately simulate the actual service conditions of the secondary loop pipelines in nuclear power plants under high temperature, high pressure, and gas-liquid two-phase impact environments. At the same time, by using the DCPD measurement system integrated in the detachable test section, the real-time monitoring of the corrosion thinning rate of materials is realized, overcoming the lag of traditional off-line measurement methods, and improving the timeliness and accuracy of experimental data. In addition, the design of the detachable test section increases the versatility and flexibility of the device, can meet different experimental requirements, and reduces the experimental cost. Overall, the device realizes high-precision corrosion rate measurement, providing strong technical support for the research of flow-accelerated corrosion and material evaluation. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is the overall structure diagram of the device for testing the flow-accelerated corrosion performance of high-temperature water vapor pipelines of the present invention;

[0026] Figure 2 It is the front view and cross-sectional view of the DCPD measurement system of the present invention;

[0027] Figure 3 It is the axonometric view of the DCPD measurement system of the present invention;

[0028] Figure 4 It is the front view and cross-sectional view of the sealing assembly in the device of the present invention;

[0029] Figure 5 It is the front view and cross-sectional view of the electrode penetration assembly in the present invention;

[0030] Figure 6 It is the structural schematic diagram of the specimen clamping assembly in the present invention.

[0031] In the figure: 1. Steam generator; 2. Rotary vane steam-water separator; 3. Corrugated steam dryer; 4. Steam outlet; 5. Steam turbine; 6. Shielded motor; 7. Balanced flowmeter; 8. Centrifugal pump; 9. Spray flowmeter; 10. Ultrasonic droplet generator; 11. Nozzle; 12. Pressure gauge; 13. Thermometer; 14. Removable test section; 15. Sheet test section housing; 16. Sheet sample; 17. Specimen clamping assembly; 18. Electrode penetrator; 19. Electrode wire; 20. DCPD sensor assembly; 21. Fluid channel; 22. Sealing assembly; 23. Bolt hole; 24. First fixed flange; 25. Second fixed flange; 26. Gas-liquid reflux pipeline; 27. Liquid level sensor; 28. Heating rod; 29. Make-up pipeline; 30. Let-down pipeline; 31. Regenerative heat exchanger; 32. Water chemistry circuit control system; 33. Compression nut; 34. Penetrator water-cooling jacket; 35. Fixture; 36. Ceramic insulating sheet; 37. Penetrator housing; 38. Four-hole ceramic tube 1; 39. Fluororubber seal; 40. Four-hole ceramic tube 2; 41. Compression sleeve. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] To simulate the actual service environment of the steam transmission pipeline in the secondary loop of a nuclear reactor, complete the tests of corrosion morphology and thinning rate to explain the mechanism of gas-liquid two-phase flow accelerated corrosion, and supplement and improve the deficiencies and shortcomings of in-situ monitoring of the test section thickness in the existing system, the present invention proposes a test device and method for online evaluating the gas-liquid two-phase flow accelerated corrosion performance. Through the high-speed steam circulation drive technology and the steam-water mixing control technology, a test platform for the steam pipeline is built, and combined with the online corrosion measurement direct current potential drop (DCPD) technology, the DCPD signal measurement electrodes are effectively clamped and sealed. Among them, DCPD (Direct Current Potential Drop) is a technology used to measure the corrosion thinning rate or crack growth rate of materials. Its principle is to apply a direct current at both ends of the specimen and detect the change in voltage drop caused by material corrosion or crack growth, so as to calculate the corrosion thinning rate or crack growth of the material in real time.

[0034] Through this device, the accurate simulation of temperature, humidity, flow rate and pressure can be ensured, overcoming the disadvantages of measurement lag, data discreteness and insufficient measurement accuracy of traditional measurement methods, providing high-time-resolution and high-precision corrosion rate monitoring, improving the accuracy and repeatability of experimental data, so as to ensure the reasonableness and accuracy of the results of the gas-liquid two-phase flow accelerated corrosion test.

[0035] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Example 1

[0037] Refer to Figures 1 to 6 As shown, Example 1 of the present invention provides a device for testing the flow accelerated corrosion performance of a high-temperature water vapor pipeline, including a steam generating device, a steam compressor, a spraying system, a detachable test section 14, a DCPD measurement system and a water chemistry control system.

[0038] Specifically, as Figure 1 shown, the steam generating device includes a steam generator 1, a rotary vane steam-water separator 2, and a corrugated steam dryer 3. A steam outlet 4 is opened at the top of the steam generator 1, and a heating rod 28 is provided at the bottom for heating the liquid water to form saturated steam. The initial steam first passes through the rotary vane steam-water separator 2, and most of the water droplets are separated by centrifugal force, and then enters the corrugated steam dryer 3. Through multiple turns and collisions of the steam in the corrugated channel, the remaining tiny water droplets are further removed. After these two steps of treatment, the steam flowing out of the steam outlet 4 has a higher dryness, providing a more stable and controllable steam source for subsequent experiments. The dried steam enters the detachable test section 14 through a pipeline.

[0039] In the above embodiment, the steam and water are initially separated by the rotary vane steam-water separator 2, reducing the water content in the steam. The corrugated steam dryer 3 further reduces the water content in the steam and increases the dryness of the steam. This secondary drying treatment can more precisely control the initial humidity of the steam, providing a more stable and controllable steam source for subsequent steam-water mixing control, thereby improving the accuracy and repeatability of the experiment.

[0040] In a specific embodiment, the steam generator 1 is connected with a pressure gauge 12 and a thermometer 13. The pressure gauge 12 is used to detect and display the internal pressure of the steam generator 1; the thermometer 13 is used to detect and display the internal temperature of the steam generator 1;

[0041] As Figure 1As shown, the steam compressor is connected to the middle of the steam generator 1 through the gas-liquid reflux pipeline 26. The steam compressor includes a steam turbine 5 and a canned motor 6. The steam turbine 5 is used to compress steam to increase the pressure difference between the upstream and downstream of the test section by ≥0.2 MPa. The canned motor 6 provides a stable and controllable driving force to drive the steam turbine 5 to achieve high-speed circulating flow of steam in the pipeline. The steam turbine 5 and the canned motor 6 together form the steam compressor to achieve high-flow-rate control of the steam in the pipeline.

[0042] As Figure 1 shown, the spray system includes a centrifugal pump 8, a spray flowmeter 9, an ultrasonic droplet generator 10, and a nozzle 11. The centrifugal pump 8 is connected to one side of the steam generator 1 near the bottom to regulate the flow rate of the liquid phase. The spray flowmeter 9 measures the water vapor flow rate in the steam flow. The ultrasonic droplet generator 10 uses ultrasonic waves to convert water into fine droplets. The nozzle 11 controls the distribution of the droplets in the steam flow to ensure that the required humidity is evenly contained in the steam. Based on the above structure, the spray system forms controllable water chemistry droplets in the steam flow by spraying, and at the same time realizes adjustable droplet size and humidity.

[0043] The detachable test section 14 adopts a detachable design and includes components such as straight pipes, elbows, reducers, and tees. It is connected to the test loop with the first fixed flange 24 and can be replaced as a whole. A DCPD measurement system is connected inside the detachable test section 14. As Figure 2 shown, the DCPD measurement system includes a sheet-shaped test section housing 15, a specimen clamping assembly 17, an electrode penetration assembly, an electrode wire 19, and a DCPD sensor assembly 20. Multiple sheet-shaped specimens 16 are evenly distributed in the inner cavity of the sheet-shaped test section housing 15. A pair of measurement electrodes are symmetrically arranged on both sides of each sheet-shaped specimen 16 to form multiple independent DCPD measurement circuits. Both ends of the sheet-shaped test section housing 15 are connected to the pipeline of the detachable test section 14 through the first fixed flange 24. Bolt holes 23 are provided on the first fixed flange 24 for detachable connection. In this embodiment, multiple sheet-shaped specimens 16 are arranged in the test section, and a pair of measurement electrodes are symmetrically arranged on both sides of each specimen to form multiple independent DCPD measurement circuits, realizing online measurement of the thinning rates of multiple parts, multiple specimens, and multiple materials on the pipe wall.

[0044] In the above embodiment, the sheet-shaped test section housing 15 is made of a stainless steel cylinder to maintain the high-temperature and high-pressure water vapor environment inside the test section; the sheet-shaped specimens 16 are fixed and directly exposed to the high-temperature and high-flow-rate droplet erosion environment; the electrode penetration assembly ensures the stable installation, electrical insulation, and sealing of the electrodes; the electrode wire 19 transmits the electrical signal from the inside of the test section to the external measurement system to ensure the stability of DCPD measurement.

[0045] In a specific embodiment, the DCPD sensor assembly 20 is made of the same material as the pipe fitting to be measured and is installed in the detachable test section 14. It includes multiple high-temperature electrodes and measurement electrodes. A pair of measurement electrodes are symmetrically arranged on both sides of each sheet specimen 16. The on-line measurement is carried out by using the direct current potential drop (DCPD) technology. By applying a constant current on both sides of the specimen, the change of the specimen voltage with the corrosion time is measured, and the real-time thinning rate of the material is calculated.

[0046] As Figure 4 shown, a fluid channel 21 is formed inside the sheet test section housing 15, and sealing assemblies 22 are provided at both ends. The shown fluid channel 21 is used for the flow of high-speed droplets and steam; the shown sealing assemblies 22 use high-temperature resistant sealing rings and gaskets to ensure that the experimental medium will not leak, and at the same time maintain the stable pressure inside the test section.

[0047] As Figure 5 shown, the electrode penetration assembly includes an electrode penetrator 18, a penetrator housing 37, a penetrator water-cooling jacket 34, an insulating connector, a compression sleeve 41, a compression nut 33, and a second fixing flange 25. Among them, the electrode penetrator 18 has a penetrator housing 37 outside it, and the penetrator housing 37 is sleeved with a penetrator water-cooling jacket 34. In a high-temperature and high-pressure water vapor environment, the electrode penetrator 18 and the measurement system may be affected by high temperature. The penetrator water-cooling jacket 34 can take away heat through circulating cooling water, reduce the temperature of the electrode penetrator 18 and the measurement system, thereby protecting them from high-temperature damage and ensuring the stability and accuracy of the measurement. One end of the penetrator housing 37 is connected to the sheet test section housing 15 through the second fixing flange 25, and the other end is fixed through the compression sleeve 41 and the compression nut 33. The electrode penetrator 18 inside the penetrator housing 37 is insulated through an insulating connector, forming insulation between the compression sleeve 41 and the compression nut 33. Specifically, the insulating connector includes a four-hole ceramic tube one 38, a four-hole ceramic tube two 40, and a fluororubber seal 39. The four-hole ceramic tube one 38 is arranged inside the penetrator housing 37, the four-hole ceramic tube two 40 is arranged inside the compression sleeve 41, and the fluororubber seal 39 is located between the four-hole ceramic tube one 38 and the four-hole ceramic tube two 40.

[0048] As Figure 6 shown, both ends of the electrode penetration assembly are connected to the specimen clamping assembly 17. The sheet specimen 16 is clamped inside the specimen clamping assembly 17. Both ends of the sheet specimen 16 are connected to measurement electrodes. The measurement electrodes are connected to the DCPD sensor assembly 20 through the electrode penetrator 18. Both ends of the sheet specimen 16 have clamps 35 for fixing, and a ceramic insulating sheet 36 is padded between the clamps 35 and the sheet specimen 16.

[0049] The embodiment of the present invention is designed with an electrode penetrator 18, which can ensure the stable installation, electrical insulation and sealing of the measurement electrode, and transmit the electrical signal from the inside of the test section to the external measurement system.

[0050] As Figure 1 shown, the water chemistry control system includes a gas-liquid reflux pipeline 26, a liquid level sensor 27, a charging pipeline 29, a discharging pipeline 30, a regeneration heat exchanger 31 and a water chemistry loop control system 32. The water chemistry control system adds treated water to the experimental loop through the charging pipeline 29 and discharges part of the circulating water through the discharging pipeline 30. The regeneration heat exchanger 31 is used to adjust the water temperature and maintain the thermal balance of the system. The water chemistry control system can continuously monitor parameters such as the pH value, dissolved oxygen content, and conductivity of the circulating water, and adjust these parameters by adding chemical reagents to keep them within the preset range.

[0051] In actual operation, first, high-temperature and high-pressure steam is generated by a steam generating device, and then it is pressurized by a steam compressor to form high-velocity steam. The spray system introduces controlled droplets into the steam flow to form a gas-liquid two-phase flow simulating the actual working conditions. This gas-liquid two-phase flow passes through the detachable test section 14, and the DCPD measurement system installed therein can monitor the corrosion thinning rate of the material in real time. Throughout the process, the water chemistry control system ensures the stability and controllability of the experimental conditions.

[0052] In a specific embodiment, the liquid level sensor 27 is arranged at the bottom and the middle side of the steam generator 1, that is, a set of liquid level sensors 27 is arranged at the bottom and the middle side of the steam generator 1 respectively for realizing liquid level control, and the liquid level is controlled within the sensor range throughout the experimental process.

[0053] In a specific embodiment, a balanced flowmeter 7 is used to measure the dry steam flow rate entering the pipeline. The balanced flowmeter 7 is installed on the pipeline after the steam generator 1 and before the spray system. The balanced flowmeter 7 can accurately measure the steam flow rate under high-temperature and high-pressure conditions, improving the accuracy of flow measurement. By accurately measuring the dry steam flow rate, the steam flow velocity can be better controlled and adjusted to ensure the stability and repeatability of the experimental conditions. Combining with the measurement of the liquid phase flow rate of the spray system, the ratio of the gas-liquid two-phase flow can be accurately calculated and controlled, providing a basis for studying the flow-accelerated corrosion under different gas-liquid ratios.

[0054] In actual operation, after the dry steam is pressurized by the steam compressor, the flow rate is measured by the balanced flowmeter 7. The data of the balanced flowmeter 7 can be real-time fed back to the control system to adjust the output of the steam compressor to maintain the required steam flow velocity. At the same time, this flow rate data can also be combined with the liquid phase flow rate data of the spray system to accurately calculate and control the ratio of the gas-liquid two-phase flow entering the test section.

[0055] The working principle of Embodiment 1 of the present invention is as follows:

[0056] The high-speed steam circulation drive technology increases the pressure difference (≥0.2 MPa) between the upstream and downstream of the test section through a steam compressor, realizes the control of high steam velocity in the pipeline, and can form turbulent wet steam in the pipe system components within the speed range of 0 - 60 m / s. The maximum pressure can reach 6 MPa, and the highest test temperature can reach 275°C. At the same time, it realizes high-precision on-line corrosion rate monitoring, providing a reliable experimental platform for studying the flow-accelerated corrosion performance of the secondary circuit pipeline materials in nuclear power plants. The steam-water mixing control technology uses ultrasonic waves to convert water into fine droplets, controls the size, quantity, and distribution of the droplets, and uniformly introduces them into the steam flow through nozzle 11, realizing continuously adjustable steam humidity and droplet size that can simulate actual working conditions. The distributed DCPD sensor array layout measures the change of the specimen voltage with corrosion time by applying a constant current on both sides of the specimen, calculates the real-time thinning rate of the material, overcomes the difficulties of sealing, insulation, and small-signal measurement in high-temperature and high-pressure environments, and realizes high-time-resolution and high-precision corrosion rate monitoring. The electrode penetrator 18 ensures the stability of DCPD measurement and solves the sealing and insulation problems in high-temperature and high-pressure environments.

[0057] Through the cooperation of the above technical features, this test platform can accurately simulate the actual service environment of the secondary circuit pipeline in a nuclear power plant, realize the accurate control of temperature, humidity, flow rate, and pressure, and at the same time provide high-precision on-line corrosion rate monitoring, overcome the shortcomings of traditional measurement methods, and improve the accuracy and repeatability of experimental data.

[0058] Embodiment 2

[0059] Embodiment 2 of the present invention also provides a method for testing the flow-accelerated corrosion performance of high-temperature water vapor pipelines. According to the high-temperature water vapor pipeline flow-accelerated corrosion performance testing device described in any one of the above, it includes the following steps:

[0060] Step S1, steam generation: Generate high-temperature and high-pressure steam through a steam generation device. The heating rod 28 at the bottom of the steam generator 1 heats the liquid-phase water to form saturated steam, which undergoes secondary drying treatment through the vane-type steam-water separator 2 and the corrugated steam dryer 3 to improve the dryness of the steam.

[0061] Step S2, steam pressurization: Use a steam compressor to pressurize the steam to form high-velocity steam.

[0062] In some embodiments, the steam turbine 5 and the shielded motor 6 increase the pressure difference between the upstream and downstream of the test section by ≥0.2 MPa to realize the control of high steam velocity in the pipeline.

[0063] Step S3, gas-liquid mixing: Introduce the controlled droplets into the steam flow through a spray system to form a gas-liquid two-phase flow.

[0064] Step S4, data measurement: Introduce the gas-liquid two-phase flow into the detachable test section 14, and use the DCPD measurement system installed therein to monitor the corrosion thinning rate of the material in real time.

[0065] Step S5, liquid level maintenance: Use the water chemistry control system to make the water chemistry in the experimental loop controllable, keep the liquid level in the steam generator 1 stable, and ensure the stability and controllability of the experimental conditions.

[0066] The high-temperature water-vapor pipeline flow-accelerated corrosion performance test device and method of the present invention achieve accurate simulation of the actual service environment of the secondary loop pipelines in nuclear power plants and high-precision monitoring of corrosion performance through a variety of innovative designs. The device uses a steam compressor to form a high-velocity steam flow, which can simulate the turbulent wet steam in the pipeline at 0 - 60 m / s, with a maximum pressure of up to 6 MPa and a maximum test temperature of 275 °C, providing reliable experimental conditions for studying flow-accelerated corrosion. The spray system uses ultrasonic technology to convert water into fine droplets and uniformly introduces them into the steam flow through the nozzle 11 to achieve continuous adjustment of the steam humidity, and the droplet size and distribution can simulate the actual working conditions. The DCPD measurement system is integrated in the detachable test section 14. By applying a constant current on both sides of the specimen and measuring the voltage change to calculate the corrosion thinning rate of the material in real time, it overcomes the difficulties of sealing, insulation, and small-signal measurement in high-temperature and high-pressure environments, and realizes high-time-resolution and high-precision corrosion rate monitoring. At the same time, the water chemistry control system can monitor and adjust parameters such as the pH value, dissolved oxygen content, and conductivity of the circulating water in real time to ensure the stability and controllability of the experimental conditions. Generally speaking, the present invention not only accurately simulates the actual working conditions, but also provides high-precision corrosion rate monitoring, overcomes the lag and low precision problems of traditional measurement methods, improves the accuracy and repeatability of experimental data, and provides strong technical support for the corrosion research and safety assessment of the secondary loop pipelines in nuclear power plants.

[0067] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0068] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A test device for the flow-accelerated corrosion performance of high-temperature water vapor pipelines, characterized in that, It includes a detachable test section (14), a steam generator (1) connected to the inlet end of the detachable test section (14), a spray system, and a steam compressor at the outlet end; the steam compressor is connected to the outlet end of the detachable test section (14) and the steam generator (1) for pressurizing the steam to form a high-velocity steam flow; one end of the spray system is connected to the bottom of the steam generator (1), and the other end is provided on the pipeline from the steam generator (1) to the detachable test section (14) to form a nozzle (11) for introducing liquid droplets into the steam flow to form a gas-liquid two-phase flow; a DCPD measurement system is integrated in the detachable test section (14), and the DCPD measurement system includes a specimen clamping assembly (17), an electrode penetration assembly, and a DCPD sensor assembly (20). The specimen clamping assembly (17) clamps a sheet specimen (16) in the detachable test section (14) and exposes it to the gas-liquid two-phase flow. The electrode penetration assembly penetrates the detachable test section (14) and connects the sheet specimen (16) and the DCPD sensor assembly (20) through an electrode wire (19).

2. The flow-accelerated corrosion performance test device for high-temperature water vapor pipelines according to claim 1, wherein The DCPD measurement system includes a sheet test section housing (15), an electrode wire (19), and the specimen clamping assembly (17), the electrode penetration assembly, and the DCPD sensor assembly (20); a plurality of sheet specimens (16) are equidistantly arranged in the inner cavity of the sheet test section housing (15), and a pair of measurement electrodes are symmetrically arranged on both sides of each sheet specimen (16) to form multiple independent DCPD measurement circuits.

3. The high-temperature water vapor pipeline flow-accelerated corrosion performance test device according to claim 2, wherein The electrode penetration assembly includes a penetration housing (37), and an electrode penetrator (18) is accommodated inside the penetration housing (37); a penetration water-cooling sleeve (34) is sleeved outside the penetration housing (37), and an insulating connector is connected between the inside and the electrode penetrator (18); one end of the penetration housing (37) is connected to the sheet test section housing (15) through a second fixing flange (25), and the other end is sealed through a compression sleeve (41) and a compression nut (33).

4. The flow-accelerated corrosion performance test device for high-temperature water vapor pipelines according to claim 1, characterized in that, The steam compressor includes a steam turbine (5) and a canned motor (6). The inlet of the steam turbine (5) is connected to the outlet end of the detachable test section (14), and the outlet of the canned motor (6) is connected to the steam generator (1).

5. The flow-accelerated corrosion performance test device for high-temperature water vapor pipelines according to claim 1, wherein The spray system includes a centrifugal pump (8), a spray flowmeter (9), an ultrasonic droplet generator (10), and a nozzle (11). The centrifugal pump (8) is connected to the bottom of the steam generator (1); the ultrasonic droplet generator (10) is connected to the nozzle (11) through the spray flowmeter (9).

6. The high-temperature water vapor pipeline flow-accelerated corrosion performance testing device according to claim 5, characterized in that, A spray flowmeter (9) is connected to the pipeline from the steam generator (1) to the detachable test section (14), and the spray flowmeter (9) is located upstream of the nozzle (11).

7. The flow-accelerated corrosion performance test device for high-temperature water vapor pipelines according to claim 1, characterized in that, A steam outlet (4) is opened at the top of the steam generator (1), and a rotary vane steam-water separator (2) and a corrugated steam dryer (3) are provided inside.

8. The flow-accelerated corrosion performance test device for high-temperature water vapor pipelines according to claim 7, characterized in that, The bottom of the steam generator (1) is also connected to a water chemistry control system, which includes a liquid level sensor (27), a regenerative heat exchanger (31) and a water chemistry loop control system (32). The liquid level sensor (27) is arranged at the bottom and the middle of the steam generator (1), and the regenerative heat exchanger (31) adjusts the temperature of the circulating water through an upper charging pipe (29) and a lower discharge pipe (30).

9. A method for testing the flow-accelerated corrosion performance of high-temperature water vapor pipelines, according to the high-temperature water vapor pipeline flow-accelerated corrosion performance testing device described in any one of claims 1 to 8, characterized in that, The following steps are involved: S1. Generate high-temperature and high-pressure steam through a steam generating device; S2, pressurizing the steam using a steam compressor to form high-flow steam; S3, introducing the controlled droplets into the steam flow through the spray system to form a gas-liquid two-phase flow; S4, introducing a gas-liquid two-phase flow into the detachable test section (14), and using a DCPD measurement system in the detachable test section (14) to monitor the corrosion thinning rate of the material in real time; S5. Use water chemistry control system to ensure the stability and controllability of experimental conditions.

10. The method for testing the flow-accelerated corrosion performance of high-temperature water vapor pipelines according to claim 9, characterized in that The steam compressor increases the pressure difference between the upstream and downstream of the test section by ≥0.2 MPa through the steam turbine (5) and the canned motor (6), thereby achieving high flow rate control of the steam in the pipeline.

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