Nuclear power water intake open channel flow field analysis method based on physical model test

Abstract

The invention relates to the technical field of crossing of water conservancy and nuclear power engineering, in particular to a nuclear power water taking open channel flow field analysis method based on a physical model test, and solves the problems that flow field analysis in the prior art mainly depends on theoretical calculation or numerical simulation, flow field characteristics under the combined action of tidal current, waves, water taking operation and other factors are difficult to truly restore, and the flow field analysis accuracy is low. And the analysis result is greatly deviated from the actual analysis result. The method comprises the following steps: constructing a physical model for accurately simulating key facilities such as a water intake, a drain grating net and a pump room, setting multiple typical working conditions, carrying out a flow field simulation test, and recording data such as a flow velocity, a flow direction and a water level. Through a physical model test means, actual water flow characteristics under a complex marine environment and various working conditions can be reflected more truly, the accuracy and reliability of flow field analysis are remarkably improved, and a scientific basis and technical support are provided for design, operation and risk assessment of a water intake system of a nuclear power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of intersection between water conservancy and nuclear power engineering, and in particular to a flow field analysis method for a nuclear power water intake open channel based on a physical model test. Background Art

[0002] Flow field analysis of nuclear power plant water intake channels is a key component of nuclear power plant water intake system design and safety assessment. It primarily studies the flow distribution characteristics of these channels under varying tidal conditions and operating conditions. Flow field analysis accurately captures flow velocity and direction, as well as its impact on the movement of floating debris. This allows for the assessment of the water intake system's safety and cooling source risk control capabilities, which is crucial for ensuring stable nuclear power plant operation.

[0003] Existing flow field analysis methods primarily rely on theoretical calculations or numerical simulations, which significantly oversimplify the simulation of complex marine environments and actual engineering boundary conditions. This makes it difficult to accurately reproduce the flow field characteristics under the combined influence of multiple factors, such as tidal currents, waves, and water intake operations. Specifically, for risk assessments of nuclear power plant water intakes that may be affected by blockages such as floating debris and marine organisms, existing methods have low accuracy in predicting the movement paths and accumulation trends of blockages, failing to provide reliable support for water intake safety. These issues directly lead to deviations in water intake system safety assessments, increase uncertainty in identifying cooling source risks, and make it difficult to meet the requirements of high-standard, high-reliability nuclear power plant engineering designs. More seriously, these issues may lead to water intake design defects, which can cause insufficient cooling water flow and even major safety incidents such as reactor shutdowns.

[0004] Therefore, to address the shortcomings of existing technologies, we urgently need a nuclear power plant water intake open channel flow field analysis method based on physical model testing to solve this problem. This new technology should significantly improve the accuracy and intuitiveness of nuclear power plant water intake open channel flow field analysis, while better reflecting the actual water flow characteristics under complex marine environments and various operating conditions, providing strong support for the safe design of nuclear power plant water intake systems and cold source risk assessment. Summary of the Invention

[0005] The purpose of the present invention is to provide a flow field analysis method for nuclear power water intake open channels based on physical model experiments, which solves the problem that the existing flow field analysis methods in the prior art mainly rely on theoretical calculations or numerical simulations, which are greatly simplified when simulating complex marine environments and actual engineering boundary conditions, and are difficult to truly restore the flow field characteristics under the combined action of multiple factors such as tides, waves, and water intake operations.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A flow field analysis method for nuclear power plant water intake open channels based on physical model testing involves constructing a physical model of the water intake open channel. This model must accurately simulate key facilities such as the water intake, trash screen, and pump house to ensure that the water flow between the model and the prototype is similar.

[0008] Set a variety of test conditions, including but not limited to 100-year high tide, average tide, average low tide, 33-year low tide and 100-year low tide, as well as different water intake flow rates and trash net clogging rates;

[0009] Simulate flow field characteristics under different working conditions in physical models, and use advanced measuring instruments to record key parameters such as flow velocity, flow direction, and water level to ensure data accuracy and integrity;

[0010] Conduct in-depth analysis of recorded flow field characteristic data to assess water intake safety and cold source risks at water intakes under different operating conditions, and identify potential areas of abnormal flow fields;

[0011] Based on the analysis results, optimization suggestions for the open water intake channel design are put forward to improve the safety and stability of the water intake system.

[0012] Preferably, the physical model is constructed at a scale of 1:50, which is chosen based on the similarity of water flow motion between the model and the prototype to ensure that the test results can accurately reflect the actual situation.

[0013] Preferably, the blockage rate of the trash net includes multiple blockage conditions such as 0%, 10%, 30%, 50% and 70%, so as to fully simulate the flow field characteristics under different blockage degrees and provide a scientific basis for the design and optimization of the trash net.

[0014] Preferably, the analysis of flow field characteristics includes flow velocity distribution, water level changes, vortex conditions, etc. near the water intake, and a comprehensive assessment of water intake safety and cold source risks is conducted through quantitative and qualitative analysis.

[0015] Preferably, the optimization suggestions include adjusting the location of the water intake, optimizing the structure of the trash screen, improving the water intake method of the pump room, etc., aiming to improve the efficiency and safety of the water intake system.

[0016] Preferably, the physical model test also needs to consider the impact of environmental factors such as water temperature and water quality on flow field characteristics to more comprehensively evaluate the performance of the water intake system.

[0017] Preferably, the method can be combined with numerical simulation technology to verify and supplement the results of physical model tests, thereby improving the accuracy and reliability of flow field analysis.

[0018] The present invention has at least the following beneficial effects:

[0019] In view of the problem that the traditional theoretical calculation or numerical simulation in the background art is difficult to truly restore the flow field characteristics under the joint action of multiple factors such as tidal current, wave, water intake operation and the like, the present application effectively improves the reproduction capability of the water flow behavior under complex marine environment by constructing a high-precision physical model and carrying out tests in combination with multiple actual operation conditions, makes up for the deficiency of numerical simulation in simplifying boundary conditions, and improves the authenticity and reliability of flow field analysis; for the problem of low accuracy in predicting the movement path and aggregation trend of the blockage, the present application can intuitively capture the migration track and possible aggregation area of the floating object under different flow field conditions through high-resolution flow velocity and flow direction measurement means, and provides data support for scientific assessment of the cold source risk; at the same time, by setting multiple extreme water levels and operation conditions (such as 100-year low tide, high blockage rate of trash screen and the like), the safety check of the water intake system under extreme conditions is realized, the defects of the water intake are avoided due to design conservatism or oversight, and thus the probability of insufficient cooling water flow or even shutdown accident is reduced; in addition, the present application can also supplement and verify the physical model test results in combination with numerical simulation technology, further improves the integrity and accuracy of flow field analysis, and provides a more comprehensive and scientific technical basis for the optimized design, safety assessment and operation and maintenance of the water intake system of the nuclear power plant. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Fig. 1 The flowchart of the present application is shown in the figure.

[0022] Fig. 2 The flowchart of the flow field characteristic data of the present application is shown in the figure. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0024] Embodiment one

[0025] Please refer to Figs. 1-2As shown, a nuclear power water intake open channel flow field analysis method based on physical model testing in this embodiment includes constructing a physical model of the water intake open channel, which needs to accurately simulate key facilities such as the water intake, trash net, pump room, etc. to ensure that the water flow movement between the model and the prototype is similar; setting multiple test conditions, including but not limited to a 100-year high tide level, average tide level, average low tide level, 33-year low tide level, and 100-year low tide level, as well as different water intake flow rates and trash net blockage rates; simulating the flow field characteristics under different working conditions in the physical model, and using advanced measuring instruments to record key parameters such as flow velocity, flow direction, and water level to ensure the accuracy and completeness of the data; conducting an in-depth analysis of the recorded flow field characteristic data, evaluating the water intake safety and cold source risk of the water intake under different working conditions, and identifying potential flow field abnormality areas; and proposing optimization suggestions for the water intake open channel design scheme based on the analysis results to improve the safety and stability of the water intake system. The analysis method based on physical model testing described in this invention was employed to analyze the flow field in the open intake channel of the combined pump house for Units 3 and 4 at the Zhangzhou Nuclear Power Plant in Fujian Province. First, a physical model of the intake channel was constructed, accurately simulating key facilities such as the intake, trash screen, and pump house. Then, various test conditions were established, including water levels such as the 100-year high tide and average tide, as well as varying intake flow rates and trash screen blockage rates. The physical model simulated the flow field characteristics under various operating conditions, and advanced measuring instruments were used to record key parameters such as flow velocity, flow direction, and water level. Through in-depth analysis of the recorded flow field characteristic data, the safety and cold source risk of the intake under various operating conditions were assessed. Finally, based on the analysis results, optimization recommendations for the intake channel design were proposed, such as adjusting the intake location and optimizing the trash screen structure, to improve the safety and stability of the intake system. Through physical model testing, this invention accurately simulates the flow field characteristics of the intake channel under various operating conditions, including flow velocity distribution, flow direction, and vorticity. Based on the flow field analysis results, the water intake safety and cold source risks of the water intake under different working conditions can be comprehensively evaluated, and potential abnormal flow field areas can be identified. According to the results of the physical model test, the design scheme of the water intake open channel can be optimized, such as adjusting the water intake position, optimizing the structure of the trash net, improving the water intake method of the pump room, etc., to improve the safety and stability of the water intake system. In addition, the present invention can also be combined with numerical simulation technology to verify and supplement the results of the physical model test, thereby improving the accuracy and reliability of the flow field analysis. Compared with the existing technology, the present invention has higher analysis accuracy and a wider range of applications, and can provide a more comprehensive scientific basis for the design, operation and maintenance of nuclear power water intake systems.

[0026] Statistics of characteristic point flow velocity under the current dredging scheme for units 1-4

[0027] Unit: m / s

[0028]

[0029] First, a physical model of the water intake channel is constructed, which accurately simulates key facilities such as the water intake, trash screen, and pump house, ensuring geometric similarity and dynamic similarity between the model and the prototype. Then, multiple typical operating conditions are set, covering extreme water level conditions and operating parameter combinations, to comprehensively reflect the complex hydraulic conditions under actual operating environments. Next, flow field simulation tests are conducted in the physical model, using advanced measuring instruments such as ultrasonic Doppler flow meters and ultrasonic level meters to record key hydrodynamic parameters such as flow velocity, flow direction, and water level. Subsequently, the obtained flow field data are systematically analyzed to assess the safety of the water intake and the risk level of the cold source under different operating conditions, and to identify possible abnormal flow field areas such as vortex zones and low-flow accumulation zones. Finally, optimization suggestions are proposed based on the analysis results, including adjusting the water intake position, optimizing the trash screen structure, and improving the pump house water intake method, to enhance the safety and stability of the water intake system. This method has been successfully applied in the flow field analysis of the water intake channel of the combined pump house of Units 3 and 4 of the Zhangzhou Nuclear Power Plant in Fujian, verifying its scientificity and engineering applicability.

[0030] Example Two

[0031] Please refer to Figs. 1-2 The flow field analysis method of the nuclear power water intake channel based on physical model test in the embodiment has a construction scale of 1:50 for the physical model. The selection of this scale is based on the similarity of water flow movement between the model and the prototype, ensuring that the test results can accurately reflect the actual situation. The trash screen blockage rate includes multiple blockage conditions such as 0%, 10%, 30%, 50%, and 70%, to comprehensively simulate the flow field characteristics under different blockage levels and provide a scientific basis for the design and optimization of the trash screen. The analysis of flow field characteristics includes flow velocity distribution near the water intake, water level changes, vortex conditions, etc., and through quantitative and qualitative analysis, the safety of water intake and the risk of cold source are comprehensively evaluated. In order to verify the universality of the method described in the invention, it is applied to the flow field analysis of another nuclear power plant water intake channel. A physical model of the water intake channel is also constructed, and multiple test operating conditions are set. The flow field characteristics under different operating conditions are simulated in the physical model, and relevant parameters are recorded. Through analysis of the flow field characteristic data, the safety of the water intake and the risk of the cold source are evaluated. Based on the analysis results, corresponding optimization suggestions are proposed, such as improving the pump house water intake method and increasing the trash screen cleaning period. After implementing the optimization suggestions, the safety and stability of the water intake system have been significantly improved.

[0032] Flow velocity statistics of characteristic points under optimized dredging scheme of Units 1-4

[0033] Unit: m / s

[0034]

[0035]

[0036] The method is applied to the flow field analysis of the water intake channel of another nuclear power plant outside Zhangzhou Nuclear Power Plant in Fujian, the physical model test under different working conditions is carried out and the related parameters are recorded, the effect of verifying the applicability of the method under different engineering conditions is achieved, and the cognitive level of the flow field change law under different blockage degrees is improved.

[0037] Example Three

[0038] Please refer to Figs. 1-2 The optimization suggestions of the method include adjusting the position of the water intake, optimizing the structure of the trash screen, improving the water intake mode of the pump house, etc., aiming to improve the efficiency and safety of the water intake system. The physical model test also needs to consider the influence of environmental factors such as water temperature and water quality on the flow field characteristics, in order to more comprehensively evaluate the performance of the water intake system. The method can be combined with numerical simulation technology to verify and supplement the results of the physical model test, improving the accuracy and reliability of the flow field analysis. The method described in the present application is verified and supplemented by combining with numerical simulation technology. First, the flow field characteristic data of the water intake channel under different working conditions are obtained by using the physical model test. Then, the test results are verified by using numerical simulation technology, and it is found that they have good consistency in terms of flow velocity distribution, water level change, etc. In addition, numerical simulation technology also provides more detailed flow field information, such as vortex distribution, turbulence intensity, etc., providing a more comprehensive scientific basis for the optimization design of the water intake system.

[0039] 1-6 unit present situation dredging scheme under the characteristic point flow velocity statistics

[0040] Unit: m / s

[0041]

[0042] By optimizing the suggestions including adjusting the position of the water intake, optimizing the structure of the trash screen, improving the water intake mode of the pump house, etc., and combining with the actual operation requirements on the basis of the physical model test, targeted improvement measures are proposed, and a reasonable trash screen cleaning period is developed, achieving the practical application effect of improving the safety and stability of the water intake system and reducing the risk of cold source;

[0043] Through the physical model test, the influence of environmental factors such as water temperature and water quality is considered, and the test results are verified and supplemented by combining with the numerical simulation technology. On the basis of obtaining the physical model flow field data, the numerical simulation means is introduced, and the flow velocity distribution, water level change, vortex distribution, turbulence intensity and other parameters are compared and analyzed, so that the accuracy and integrity of the flow field analysis are improved, and the scientific nature and reliability of the design are enhanced.

[0044] The nuclear power water intake open channel flow field analysis method based on the physical model test provided by the application covers multiple key links from physical model construction, multiple working condition setting, flow field simulation test, data recording and analysis to optimization suggestion putting forward and the like. The following is the specific setting of each structure in the embodiment, which details the work flow and the corresponding beneficial effects:

[0045] Firstly, a physical model of the water intake channel is constructed, which accurately simulates key facilities such as the water intake, trash screen, pump house, etc., to ensure geometric similarity and dynamic similarity between the model and the prototype; the physical model is constructed at a scale of 1:50 to ensure that the test results accurately reflect the actual situation; then, various typical operating conditions are set, covering extreme water level conditions and operating parameter combinations, such as 100-year high tide level, average tide level, different water intake flow rates, and trash screen blockage rates, to comprehensively reflect the complex hydraulic conditions under actual operating environments, and to consider various situations such as trash screen blockage rates of 0%, 10%, 30%, 50%, and 70%, achieving a more comprehensive simulation of flow field characteristics under different blockage levels; then, flow field simulation tests are carried out in the physical model, using advanced measuring instruments such as ultrasonic Doppler flowmeters, ultrasonic water level meters, etc., to record key hydrodynamic parameters such as flow rate, flow direction, water level, etc., to ensure the accuracy and completeness of the data; thereafter, the obtained flow field data are systematically analyzed to evaluate the water intake safety and cold source risk level of the water intake under different operating conditions, identify possible abnormal flow field areas such as vortex zones, low flow rate accumulation zones, etc., and comprehensively evaluate the water intake safety and cold source risk through quantitative and qualitative analysis, achieving an improved level of understanding of the flow field variation law under different blockage levels; finally, optimization suggestions are proposed based on the analysis results, including adjusting the water intake position, optimizing the trash screen structure, improving the pump house water intake method, etc., and developing a reasonable trash screen cleaning cycle in combination with actual operating requirements, achieving the practical application effects of improving the safety and stability of the water intake system and reducing the cold source risk. In addition, by considering the influence of environmental factors such as water temperature and water quality through physical model tests, and combining numerical simulation technology to verify and supplement the test results, on the basis of obtaining physical model flow field data, numerical simulation means are introduced to compare and analyze parameters such as flow rate distribution, water level variation, vortex distribution, and turbulence intensity, achieving the effects of improving the accuracy and completeness of flow field analysis, enhancing the scientific nature and reliability of design; at the same time, numerical simulation technology also provides more detailed flow field information, further supporting the optimization design of the water intake system, thereby achieving a comprehensive evaluation and optimization of the performance of the water intake system.

[0046] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A nuclear power water intake open channel flow field analysis method based on physical model test, characterized in that: The following steps are involved: Build a physical model of the open water intake channel. This model must accurately simulate key facilities such as the water intake, trash screen, and pump house, ensuring that the water flow between the model and the prototype is similar. Set a variety of test conditions, including but not limited to 100-year high tide, average tide, average low tide, 33-year low tide and 100-year low tide, as well as different water intake flow rates and trash net clogging rates; Simulate flow field characteristics under different working conditions in physical models, and use advanced measuring instruments to record key parameters such as flow velocity, flow direction, and water level to ensure data accuracy and integrity; Conduct in-depth analysis of recorded flow field characteristic data to assess water intake safety and cold source risks at water intakes under different operating conditions, and identify potential areas of abnormal flow fields; Based on the analysis results, optimization suggestions for the open water intake channel design are put forward to improve the safety and stability of the water intake system.

2. The method for analyzing flow field of nuclear power water intake open channel based on physical model test according to claim 1 is characterized in that: The physical model was constructed at a scale of 1:50, which was chosen based on the similarity of water flow motion between the model and the prototype to ensure that the test results accurately reflect the actual situation.

3. The method for analyzing flow field of nuclear power water intake open channel based on physical model test according to claim 1 is characterized in that: The clogging rate of the trash net includes various clogging conditions such as 0%, 10%, 30%, 50% and 70%, so as to fully simulate the flow field characteristics under different clogging degrees and provide a scientific basis for the design and optimization of the trash net.

4. The method for analyzing flow field in nuclear power water intake open channel based on physical model test according to claim 1, characterized in that: The analysis of flow field characteristics includes flow velocity distribution, water level changes, vortex conditions, etc. near the water intake. Through quantitative and qualitative analysis, a comprehensive assessment of water intake safety and cold source risks is conducted.

5. The method for analyzing flow field of nuclear power water intake open channel based on physical model test according to claim 1, characterized in that: Optimization suggestions include adjusting the location of the water intake, optimizing the structure of the trash net, and improving the water intake method of the pump room, aiming to improve the efficiency and safety of the water intake system.

6. The method for analyzing flow field of nuclear power water intake open channel based on physical model test according to claim 1, characterized in that: Physical model tests also need to consider the impact of environmental factors such as water temperature and water quality on flow field characteristics in order to more comprehensively evaluate the performance of the water intake system.

7. The method for analyzing flow field of nuclear power water intake open channel based on physical model test according to claim 1, characterized in that: This method can be combined with numerical simulation technology to verify and supplement the results of physical model tests and improve the accuracy and reliability of flow field analysis.

Images