A nuclear power plant throttle device cavitation simulation system and test method

Abstract

The application belongs to the technical field of nuclear power devices, and particularly relates to a nuclear power plant throttling device cavitation simulation system and a test method. The system comprises: a test section pipeline and a test section outer pipeline; the test section pipeline is connected with the test section outer pipeline to form a test loop; a water tank is arranged on the test section outer pipeline to provide liquid with a preset flow and pressure to the test section pipeline and recover the liquid flowing out of the test section pipeline; the test section pipeline comprises: a low-pressure pipeline and a medium-pressure pipeline; a throttling orifice plate is arranged on the low-pressure pipeline and the medium-pressure pipeline; a first pressure transmitter is arranged on the outlet and the inlet of the low-pressure pipeline and the medium-pressure pipeline; a transparent pipe section is arranged after the throttling orifice plate on the low-pressure pipeline; the inner diameter of the transparent pipe section is consistent with the inner diameter of the adjacent pipeline. The embodiment of the application is used for reproducing the nuclear power field operation fault in the laboratory, analyzing the root cause of the vibration of the pressure reduction pipeline, and facilitating the test verification of the optimization and reconstruction scheme of the orifice plate.

Description

Technical Field

[0001] This application belongs to the field of nuclear power plant technology, specifically relating to a cavitation simulation system and test method for a nuclear power plant throttling device. Background Technology

[0002] In the design of nuclear power plant safety injection systems (RIS), containment spray systems (EAS), and chemical and volume control systems (RCV), orifice plates are typically used to limit flow and reduce pressure. The orifice plates generate a "jet effect" to cause localized losses, thereby meeting the strict control requirements of nuclear power plants for fluid parameters.

[0003] However, when fluid flows through an orifice plate, the sudden narrowing of the flow cross-section causes a sharp increase in fluid velocity at the constriction point behind the orifice plate. This leads to a significant pressure drop behind the orifice plate, with local pressures falling below the fluid's saturated vapor pressure, thus triggering cavitation. Cavitation not only limits system function and reduces efficiency but also causes serious vibration and noise problems, and can even damage pipes and orifice plates, posing a threat to the safe operation of nuclear power plants.

[0004] To address the series of operational problems caused by orifice plate cavitation, it is necessary to construct the system operation pipeline of a nuclear power plant in the laboratory to recreate the on-site operating conditions. This serves three purposes: first, it facilitates the reproduction of faults in the nuclear power plant's on-site operation, enabling root cause analysis; second, it is beneficial for the experimental verification of the orifice plate optimization design scheme; and third, it allows for the completion of basic research on the orifice plate cavitation mechanism through visual modifications to the experimental pipeline. Summary of the Invention

[0005] The purpose of this application is to provide a cavitation simulation system and test method for a nuclear power plant throttling device, solving the problem of how to simulate the cavitation phenomenon of throttling orifice plates in the prior art.

[0006] The technical solution to achieve the purpose of this application is as follows: The first aspect of this application provides a cavitation simulation system for a nuclear power plant throttling device, the system comprising: a test section pipeline and an external test section pipeline; The test section pipeline is connected to the external pipeline of the test section to form a test loop; a water tank is installed on the external pipeline of the test section to provide liquid with a preset flow rate and pressure to the test section and to recover the liquid flowing out of the test pipeline. The test section pipeline includes two parallel branches: a low-pressure pipeline and a medium-pressure pipeline; Both the low-pressure pipeline and the medium-pressure pipeline are equipped with orifice plates; both the outlet and inlet of the low-pressure pipeline and the medium-pressure pipeline are equipped with first pressure transmitters; a transparent pipe section is provided after the orifice plate on the low-pressure pipeline; the inner diameter of the transparent pipe section is consistent with the inner diameter of its adjacent pipeline.

[0007] Optionally, the transparent pipe section adopts an outer square and inner circle structure, and is sealed with a gasket between it and the adjacent pipe.

[0008] Optionally, a manual regulating valve is installed on the pipeline where the low-pressure pipeline and the medium-pressure pipeline merge; A first pressure transmitter is also installed before the manual regulating valve.

[0009] Optionally, the external pipeline of the test section includes two branches: a low-pressure external pipeline and a medium-pressure external pipeline; One end of the low-pressure external pipeline is connected to the water tank, and the other end is connected to the low-pressure pipeline; one end of the medium-pressure external pipeline is connected to the water tank, and the other end is connected to the medium-pressure pipeline; A low-pressure pump is installed on the low-pressure external pipeline; a medium-pressure pump is installed on the medium-pressure external pipeline.

[0010] Optionally, Y-type filters are installed on both the low-pressure external pipeline and the medium-pressure external pipeline, located before the low-pressure pump and the medium-pressure pump, respectively. Manual shut-off valves are installed before and after both the low-pressure pump and the medium-pressure pump; Both the low-pressure external pipeline and the medium-pressure external pipeline are equipped with Venturi flow meters.

[0011] Optionally, the low-pressure pump is a fixed-frequency centrifugal pump, and a first electric regulating valve for adjusting the flow rate is also provided on the low-pressure external pipeline; the medium-pressure pump is a variable-frequency centrifugal pump.

[0012] Optionally, the low-pressure external pipeline and the medium-pressure external pipeline are also provided with return pipelines; one end of the two return pipelines is connected to the water tank, and the other end is connected to the outlet of the low-pressure pump and the medium-pressure pump respectively; a second electric regulating valve is provided on the return pipeline.

[0013] Optionally, a second pressure transmitter is installed on both the low-pressure external pipeline and the medium-pressure external pipeline, respectively, before the manual shut-off valve and the Venturi flow meter.

[0014] Optionally, the system further includes a heat exchanger disposed within the water tank.

[0015] Optionally, the system may also include: a light source and a camera; The light source is used to illuminate the transparent tube segment, and the camera is used to photograph the transparent tube segment.

[0016] The second aspect of this application provides a method for simulating cavitation testing of a nuclear power plant throttling device, applicable to any one of the nuclear power plant throttling device cavitation simulation systems provided in the first aspect of this application; the method includes: The external pipeline of the test section is controlled to supply liquid with a preset flow rate and pressure to the test section, ensuring that the flow rate and pressure difference before and after the test section do not differ from the actual situation on site by a preset threshold. Cavitation phenomena were observed using a transparent pipe section. After the flow rate stabilized, vibration and cavitation measurements were performed.

[0017] The beneficial technical effects of this application are as follows: This application provides a cavitation simulation system and test method for a nuclear power plant throttling device. The system includes: a test section pipeline and an external test section pipeline; the test section pipeline and the external test section pipeline are connected to form a test loop; a water tank is installed on the external test section pipeline to provide liquid with a preset flow rate and pressure to the test section and to recover liquid flowing out of the test pipeline; the test section pipeline includes two parallel branches: a low-pressure pipeline and a medium-pressure pipeline; both the low-pressure pipeline and the medium-pressure pipeline are equipped with orifice plates; the outlet and inlet of both the low-pressure pipeline and the medium-pressure pipeline are equipped with first pressure transmitters; a transparent pipe section is installed after the orifice plate on the low-pressure pipeline; the inner diameter of the transparent pipe section is consistent with the inner diameter of its adjacent pipe. This application embodiment constructs a nuclear power plant system operation pipeline to reproduce on-site nuclear power plant operation faults in the laboratory, analyze the root causes of vibration in the depressurization pipeline, and facilitate experimental verification of orifice plate optimization and modification schemes, thereby restoring on-site operating conditions. First, it facilitates the reproduction of on-site nuclear power plant operation faults for root cause analysis; second, it is conducive to the experimental verification of orifice plate optimization design schemes; and third, it completes the basic research on orifice plate cavitation mechanism by making visual changes to the test pipeline. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a cavitation simulation system for a nuclear power plant throttling device, provided as an embodiment of this application.

[0019] In the picture: 1-Orifice plate; 2-First pressure transmitter; 3-Transparent pipe section; 4-Y-type filter; 5-Water tank; 6-Heat exchanger; 7-Low-pressure pump; 8-Manual shut-off valve; 9-Medium-pressure pump; 10-First electric regulating valve; 11-Second electric regulating valve; 12-Manual regulating valve; 13-Venturi flow meter; 14-Second pressure transmitter; 15-Light source; 16-Camera; 17-Gate valve; 18-Flow orifice plate; 19-Reducer; 20-Check valve; 21-Plug; 22-Computer. Detailed Implementation

[0020] To enable those skilled in the art to better understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only a part of the embodiments of this application, and not all of them. Based on the embodiments described in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] See Figure 1 The figure is a schematic diagram of the structure of a cavitation simulation system for a nuclear power plant throttling device provided in an embodiment of this application.

[0022] This application provides a nuclear power plant throttling device cavitation simulation system, comprising: a test section pipeline and an external test section pipeline; The test section pipeline is connected to the external pipeline of the test section to form a test loop; a water tank 5 is installed on the external pipeline of the test section to provide liquid with a preset flow rate and pressure to the test section and to recover the liquid flowing out of the test pipeline. The test section pipeline includes two parallel branches: a low-pressure pipeline and a medium-pressure pipeline; Both the low-pressure pipeline and the medium-pressure pipeline are equipped with orifice plates 1; both the outlet and inlet of the low-pressure pipeline and the medium-pressure pipeline are equipped with first pressure transmitters 2; a transparent pipe section 3 is provided after the orifice plate 1 on the low-pressure pipeline; the inner diameter of the transparent pipe section 3 is consistent with the inner diameter of its adjacent pipeline.

[0023] In this embodiment, the test pipeline section can replicate the pipeline routing, support arrangement, and installation positions and dimensions of fittings (inlet elbows, valves, orifice plates 1 and 18, etc.) at a 1:1 scale from the nuclear power plant site. Due to test conditions, some supports anchored to the wall can be replaced by supports anchored to the steel structure. According to the requirements of the nuclear power plant site, the test section pipeline includes two branches: a low-pressure pipeline and a medium-pressure pipeline. It is understood that the transparent pipe section 3 is installed after the orifice plate 1 on the low-pressure pipeline for visual observation of cavitation after the orifice plate 1. The external pipeline of the test section is used to provide liquid with a certain flow rate and pressure to the test pipeline and to recover the liquid flowing out of the test pipeline. Its pipeline routing and support arrangement can be installed according to local test conditions. The test pipeline and the external pipeline of the test section can be connected by reducers 19.

[0024] In practice, a check valve 20 can be installed at the inlet of the test pipeline to prevent liquid backflow. During the test, the gate valves 17 on the low-pressure and medium-pressure pipelines are normally open for emergency start-up and shutdown. The operating pressure range of the low-pressure pipeline inlet can be 1.8–2.0 MPa, and the operating pressure range of the medium-pressure pipeline inlet can be 9.5–10 MPa.

[0025] It should also be noted that, to facilitate simultaneous operation of both circuits, water tank 5 should be large enough, and all pipelines should extend from water tank 5. The test circuit adopts an open test bench. The liquid flows from water tank 5 into the external pipeline of the test section, then into the pipeline of the test section, and finally returns to water tank 5 to complete the circulation.

[0026] In one example, the transparent pipe segment 3 can have an outer square and inner circle structure, and be sealed with a gasket between it and the adjacent pipe.

[0027] It is understandable that the transparent pipe section 3 can adopt an outer square and inner circle structure, with an appropriate increase in wall thickness to ensure its strength. Its inner diameter is consistent with the inner diameter of the adjacent pipe, its length can be 3 to 5 times the inner diameter of the pipe, and its material can be plexiglass.

[0028] In another example, a manual regulating valve 12 may be installed on the pipeline where the low-pressure pipeline and the medium-pressure pipeline merge; A first pressure transmitter 2 is also installed before the manual regulating valve 12.

[0029] Understandably, the manual regulating valve 12 is used to regulate the back pressure of the fluid flow behind the orifice plate 1.

[0030] In some possible implementations of the embodiments of this application, the test section external pipeline may include two branches: a low-pressure external pipeline and a medium-pressure external pipeline; One end of the low-pressure external pipeline is connected to the water tank 5, and the other end is connected to the low-pressure pipeline; one end of the medium-pressure external pipeline is connected to the water tank 5, and the other end is connected to the medium-pressure pipeline; A low-pressure pump 7 is installed on the low-pressure external pipeline; a medium-pressure pump 9 is installed on the medium-pressure external pipeline.

[0031] It is understandable that liquids with preset flow rates and pressures are supplied to the low-pressure and medium-pressure pipelines respectively through low-pressure and medium-pressure external pipelines.

[0032] In one example, Y-type filters 4 can be installed on both the low-pressure external pipeline and the medium-pressure external pipeline, respectively, before the low-pressure pump 7 and the medium-pressure pump 9; Manual shut-off valves 8 are installed before and after both the low-pressure pump 7 and the medium-pressure pump 9; Venturi flow meters 13 are installed on both the low-pressure external pipeline and the medium-pressure external pipeline.

[0033] Understandably, the manual shut-off valve 8 is designed to facilitate disassembly during the operation and maintenance of the low-pressure pump 7 and the medium-pressure pump 9. During the test, the manual shut-off valve 8 was in the normally open state.

[0034] In another example, the low-pressure pump 7 can be a fixed-frequency centrifugal pump, and the low-pressure external pipeline is also equipped with a first electric regulating valve 10 for adjusting the flow rate; the medium-pressure pump 9 is a variable-frequency centrifugal pump.

[0035] In practice, the low-pressure pump 25 is a fixed-frequency centrifugal pump, which regulates the flow rate on the low-pressure external pipeline through the first electric regulating valve 10; the medium-pressure pump 9 is a variable-frequency centrifugal pump, which controls the flow rate and pressure on the medium-pressure external pipeline through frequency conversion; the low-pressure pump 7 and the medium-pressure pump 9 can be powered through a fixed power distribution room.

[0036] In another example, the low-pressure external pipeline and the medium-pressure external pipeline are also provided with return pipelines; one end of the two return pipelines is connected to the water tank 5, and the other end is connected to the outlet of the low-pressure pump 7 and the medium-pressure pump 9 respectively; a second electric regulating valve 11 is provided on the return pipeline.

[0037] Understandably, the liquid flow in the return pipeline returns directly to the water tank 5, and the required flow rate of the test pipeline is matched by adjusting the opening of the second electric regulating valve 11.

[0038] In practice, the inlet pressure of the low-pressure section can be adjusted by controlling the first electric regulating valve 10, and the opening of the second electric regulating valve 11 can be adjusted to regulate the flow in the low-pressure section. Ensure that the flow rate and the pressure difference before and after the test section do not differ from the actual flow rate by more than 5%. Check the signals of each channel (e.g., authenticity, signal-to-noise ratio), and select several signals for real-time online analysis to confirm the data's accuracy and reliability. After the flow rate stabilizes, measure vibration and cavitation, and record 100-second time-history signals for storage.

[0039] As an example, a second pressure transmitter 14 is installed on both the low-pressure external pipeline and the medium-pressure external pipeline, respectively, before the manual shut-off valve 8 and the Venturi flow meter 13.

[0040] In some possible implementations of the embodiments of this application, the system may further include: a heat exchanger 6 disposed in the water tank 5.

[0041] It is understandable that a heat exchanger 6 is placed inside the water tank 5 to prevent the temperature of the water tank 5 from rising during long-term operation.

[0042] In a specific implementation, the system may further include: a light source 15 and a camera 16; Light source 15 is used to provide supplemental lighting to transparent tube segment 3, and camera 16 is used to photograph transparent tube segment 3.

[0043] This application embodiment constructs a nuclear power plant system operation pipeline to reproduce on-site nuclear power plant operation faults in the laboratory, analyze the root causes of vibration in the depressurization pipeline, and facilitate experimental verification of orifice plate optimization and modification schemes, thereby restoring on-site operating conditions. First, it facilitates the reproduction of on-site nuclear power plant operation faults for root cause analysis; second, it is conducive to the experimental verification of orifice plate optimization design schemes; and third, it completes the basic research on orifice plate cavitation mechanism by making visual changes to the test pipeline.

[0044] Based on the cavitation simulation system for a nuclear power plant throttling device provided in the above embodiments, this application also provides a cavitation simulation test method for a nuclear power plant throttling device, which can be applied to any one of the cavitation simulation systems for a nuclear power plant throttling device provided in the above embodiments.

[0045] This application provides a method for simulating cavitation testing of a nuclear power plant throttling device, comprising: The external pipeline of the test section is controlled to supply liquid with a preset flow rate and pressure to the test section, ensuring that the flow rate and pressure difference before and after the test section do not differ from the actual situation on site by a preset threshold. Cavitation was observed using transparent pipe section 3. After the flow rate stabilized, vibration and cavitation measurements were performed.

[0046] The following is a detailed explanation of a cavitation simulation test method for a nuclear power plant throttling device provided in this application, using a specific example.

[0047] This application provides a method for cavitation simulation test of a throttling device in a nuclear power plant. Before the test, it is confirmed that the pipeline layout, support installation and throttling orifice plate 1 parameters of the test section are consistent with those of the nuclear power plant site. The test circuit is debugged and checked, and the first pressure transmitter 2, the second pressure transmitter 14 and the Venturi flow meter 13 are calibrated.

[0048] After completing the debugging and installation of the light source 15, camera 16, and computer 22, connect the vibration triaxial acceleration sensor to the data acquisition system. Conduct the test after passing the pre-test status check.

[0049] Start the low-pressure pump 7 and the medium-pressure pump 9. Adjust the inlet pressure of the low-pressure section to 1.8–2.0 MPa by controlling the first electric regulating valve 10. Adjust the opening of the second electric regulating valve 11 of the low-pressure bypass to adjust the flow rate of the low-pressure section to 90–100 m³ / h. 3 / h; By adjusting the input frequency of the medium-pressure pump 9 motor, the inlet pressure of the medium-pressure section is adjusted to approximately 9.5–10 MPa, and the flow rate is (40–45) m³ / h. 3 / h. Ensure that the flow rate and pressure difference before and after the test section do not differ from the actual site by more than 5%.

[0050] The authenticity and signal-to-noise ratio of each channel signal were checked, and several signals were selected for real-time online analysis to confirm the data's authenticity and reliability. After the flow rate stabilized, vibration and cavitation measurements were performed, and 120-second time-history signals were collected and stored.

[0051] The present application has been described in detail above with reference to the accompanying drawings and embodiments. However, the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present application. All content not described in detail in this application can be derived from existing technology.

Claims

1. A cavitation simulation system for a nuclear power plant throttling device, characterized in that, The system includes: a test section pipeline and an external test section pipeline; The test section pipeline is connected to the external pipeline of the test section to form a test circuit; a water tank (5) is provided on the external pipeline of the test section to provide liquid with a preset flow rate and pressure to the test section and to recover the liquid flowing out of the test pipeline; The test section pipeline includes two parallel branches: a low-pressure pipeline and a medium-pressure pipeline; Both the low-pressure pipeline and the medium-pressure pipeline are equipped with orifice plates (1); both the outlet and inlet of the low-pressure pipeline and the medium-pressure pipeline are equipped with first pressure transmitters (2); a transparent pipe section (3) is provided after the orifice plate (1) on the low-pressure pipeline; the inner diameter of the transparent pipe section (3) is consistent with the inner diameter of its adjacent pipeline.

2. The cavitation simulation system for a nuclear power plant throttling device according to claim 1, characterized in that, The transparent pipe section (3) adopts an outer square and inner circle structure, and is sealed with a gasket between it and the adjacent pipe.

3. The cavitation simulation system for a nuclear power plant throttling device according to claim 1, characterized in that, A manual regulating valve (12) is installed on the pipeline where the low-pressure pipeline and the medium-pressure pipeline merge. A first pressure transmitter (2) is also installed before the manual regulating valve (12).

4. The cavitation simulation system for a nuclear power plant throttling device according to claim 1, characterized in that, The test section's external pipeline includes two branches: a low-pressure external pipeline and a medium-pressure external pipeline; One end of the low-pressure external pipeline is connected to the water tank (5), and the other end is connected to the low-pressure pipeline; one end of the medium-pressure external pipeline is connected to the water tank (5), and the other end is connected to the medium-pressure pipeline; A low-pressure pump (7) is installed on the low-pressure external pipeline; a medium-pressure pump (9) is installed on the medium-pressure external pipeline.

5. The cavitation simulation system for a nuclear power plant throttling device according to claim 4, characterized in that, Y-type filters (4) are installed on both the low-pressure external pipeline and the medium-pressure external pipeline, respectively, before the low-pressure pump (7) and the medium-pressure pump (9); Manual shut-off valves (8) are installed before and after both the low-pressure pump (7) and the medium-pressure pump (9). Venturi flow meters (13) are installed on both the low-pressure external pipeline and the medium-pressure external pipeline.

6. The cavitation simulation system for a nuclear power plant throttling device according to claim 4, characterized in that, The low-pressure pump (7) is a fixed-frequency centrifugal pump, and a first electric regulating valve (10) for adjusting the flow rate is also provided on the low-pressure external pipeline; the medium-pressure pump (9) is a variable-frequency centrifugal pump.

7. The cavitation simulation system for a nuclear power plant throttling device according to claim 4, characterized in that, The low-pressure external pipeline and the medium-pressure external pipeline are also equipped with return pipelines; one end of the two return pipelines is connected to the water tank (5), and the other end is connected to the outlet of the low-pressure pump (7) and the medium-pressure pump (9) respectively; a second electric regulating valve (11) is provided on the return pipeline.

8. The cavitation simulation system for a nuclear power plant throttling device according to claim 5, characterized in that, A second pressure transmitter (14) is installed on both the low-pressure external pipeline and the medium-pressure external pipeline, respectively, before the manual shut-off valve (8) and the Venturi flow meter (13).

9. The cavitation simulation system for a nuclear power plant throttling device according to claim 1, characterized in that, The system also includes a heat exchanger (6) installed in the water tank (5).

10. The cavitation simulation system for a nuclear power plant throttling device according to any one of claims 1-9, characterized in that, The system also includes: a light source (15) and a camera (16). The light source (15) is used to supplement the light to the transparent tube segment (3), and the camera (16) is used to photograph the transparent tube segment (3).

11. A method for simulating cavitation testing of a throttling device in a nuclear power plant, characterized in that, The method is applied to the cavitation simulation system of the nuclear power plant throttling device according to any one of claims 1-10; the method includes: The external pipeline of the test section is controlled to supply liquid with a preset flow rate and pressure to the test section, ensuring that the flow rate and pressure difference before and after the test section do not differ from the actual situation on site by a preset threshold. Cavitation was observed using a transparent pipe section (3). After the flow rate stabilized, vibration and cavitation measurements were taken.

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