An experimental method for simulating the propagation characteristics of discharge noise from a water turbine.

Abstract

An experimental device for simulating the propagation characteristics of discharge noise from a water turbine includes a sealed water tank. A rotating device, comprising a shaft and a propeller, is vertically installed inside the sealed water tank. A ring pipe is located at the top of the sealed water tank, with one end connected to the sealed water tank and the other end connected to a water supply tank via a fire hose. The water supply tank is connected to a water pump via a water delivery pipe. The bottom of the sealed water tank is connected to the water supply tank via an outlet pipe. Wireless acoustic sensors are installed on the outside and top of the sealed water tank, and a hydrophone is installed inside the sealed water tank. Fiber optic sensors are also installed on the body and bottom of the sealed water tank. All wireless acoustic sensors, hydrophones, and fiber optic sensors are equipped with their own analysis devices. This device can simulate the discharge noise of a water turbine under different operating conditions. It collects and analyzes noise data in real time using wireless acoustic sensors, hydrophones, and fiber optic sensors, comprehensively evaluating the noise propagation characteristics and providing reliable experimental data for the ecological operation and noise reduction design of water turbines.

Description

Technical Field

[0001] This invention relates to the field of simulated noise detection and analysis technology, and in particular to an experimental method for simulating the propagation characteristics of discharge noise from a water turbine. Background Technology

[0002] In the field of hydropower, the turbine is a key piece of equipment, and its operating efficiency and stability directly affect the overall performance of the power station. However, during operation, the turbine generates significant noise due to the complex flow phenomena produced when water passes through the blades and guide vanes. This noise not only affects the working environment but may also adversely impact the surrounding ecological environment and residents' lives. Therefore, studying the propagation characteristics of turbine discharge noise and seeking effective control measures is of great significance.

[0003] Currently, research on turbine discharge noise has made some progress both domestically and internationally. Existing technologies mainly use two methods—experimental simulation and numerical calculation—to analyze the flow field characteristics inside and outside the turbine, and then explore the noise generation mechanism and propagation law. Experimental methods typically involve building a turbine model test rig and measuring parameters such as sound pressure level and spectral distribution under different operating conditions to assess the noise level. Numerical methods utilize computational fluid dynamics (CFD) software to simulate the internal flow field of the turbine and predict the location and intensity of the noise source.

[0004] For example, Jiang Xiaohui, Wu Daohu, and others have verified the feasibility of using noise characteristics analysis during the discharge process at locations such as the outside of the volute to diagnose turbines. However, research on the relevant noise characteristics of simulated turbine blade deformation, cracking, and other fault conditions is lacking. In the journal *Engineering Technology II*, Zhang Wei's "Fault Diagnosis System for Hydro-turbine Units Based on Noise Detection" utilizes LabVIEW virtual instrument technology and MATLAB to simulate the characteristics of discharge noise, establishing an intelligent fault diagnosis system for turbines. In the journal *Engineering Technology II*, Wu Daohu's "Research on Acoustic-Based Hydro-turbine Condition Monitoring Technology" studies cavitation and erosion of turbines based on noise characteristics. In the journal *Water*, Yuchen Liu's "Numerical Simulation Analysis of the Correlation between Hydrodynamic Noise of Hydraulic Turbines and Defects in Runner Blades" employs computational fluid dynamics (CFD) and computational acoustics (CFM)... The CA hybrid simulation calculation method was used to numerically simulate and study the hydrodynamic noise field of a water turbine. It proved the feasibility and expected reliability of measuring relevant noise and analyzing its characteristics in software. FAZENDA.B. also analyzed the noise characteristics of a water turbine blade under faulty conditions in the paper "Noise characterization of a Francis turbine in faulty conditions". This invention provides an experimental device and method for simulating the propagation characteristics of water turbine discharge noise based on existing theoretical research.

[0005] Although existing technologies have made some progress in understanding turbine discharge noise, the following shortcomings still exist: Limitations of experimental setups: Existing experimental setups are mostly designed for specific models or types of water turbines, lacking versatility and flexibility, and making it difficult to comprehensively cover the study of water turbine noise characteristics under different sizes, structures and operating conditions.

[0006] Research on noise propagation characteristics is not in-depth: Most studies focus on the analysis of noise sources, while there is a lack of systematic and in-depth exploration of the propagation characteristics of noise in complex environments, such as attenuation laws, reflection and diffraction effects.

[0007] Limited control measures: Although some noise reduction measures have been proposed, such as optimizing blade shape and improving water guiding mechanism design, in practical applications, these measures are often limited by factors such as cost and technical difficulty, and it is difficult to achieve the expected results.

[0008] Data processing and analysis methods need improvement: In terms of noise data collection, processing and analysis, more standardized and automated processes need to be established to improve data accuracy and reliability and reduce human error.

[0009] In summary, further research on the propagation characteristics of turbine discharge noise requires in-depth exploration and innovation in areas such as experimental device design, noise propagation characteristic analysis, control measure development, and data processing and analysis methods. This invention proposes an experimental device and method for simulating the propagation characteristics of turbine discharge noise. The aim is to comprehensively reveal the propagation laws of turbine discharge noise by constructing a more precise and flexible experimental platform, combined with advanced measurement and analysis techniques, thereby providing a scientific basis and technical support for noise control. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide an experimental device and method for simulating the propagation characteristics of turbine discharge noise, so as to realize the multi-dimensional simulation of the propagation characteristics of turbine discharge noise under multiple working conditions by controlling variables such as inlet and outlet water flow, motor speed and changing different blades, and at the same time, it can also simulate the noise reduction effect of turbine discharge by filling different materials in the interlayer.

[0011] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: an experimental device for simulating the propagation characteristics of discharge noise of a water turbine, including a sealed water tank, a rotating device vertically installed inside the sealed water tank, the rotating device including a rotating shaft and a paddle, a ring pipe set at the top of the sealed water tank, one end of the ring pipe being connected to the sealed water tank, and the other end being connected to a water supply tank through a fire hose, the water supply tank being connected to a water pump of the water supply tank through a water delivery pipe, the bottom of the sealed water tank being connected to the water supply tank through an outlet pipe, wireless acoustic sensors being set on the outside and top of the sealed water tank, a hydrophone being set inside the sealed water tank, and fiber optic sensors being set on the body and bottom of the sealed water tank, the wireless acoustic sensors, the hydrophone and the fiber optic sensors all having built-in analysis equipment.

[0012] In a preferred embodiment, the sealed water tank is configured as a double-layered metal cylinder with an interlayer between the two layers. A first fiber optic sensor is installed in the interlayer. A water tank base is installed at the bottom of the sealed water tank, and the water tank base is configured as a ring. Lower support structures are evenly distributed around the bottom of the water tank base. A water tank top cover is installed at the top of the sealed water tank. The water tank top cover and the sealed water tank are connected and fastened together by a spring lock. A sealing ring is installed between the water tank top cover and the sealed water tank.

[0013] In a preferred embodiment, a rotating shaft is rotatably mounted in the middle of the water tank top cover, with the lower end of the shaft suspended in the air. A motor is fixedly mounted on the top of the water tank top cover via a coupling, and several paddles are installed inside the sealed water tank at the lower part of the shaft.

[0014] In a preferred embodiment, the water supply tank is located below the sealed water tank. A water outlet pipe is installed at the bottom of the sealed water tank. The inlet of the water outlet pipe is connected to the sealed water tank, and the outlet is connected to the water supply tank. A water pump is installed in the middle of the water supply tank. The outlet of the water pump is connected to the inlet of the water supply pipe, and the outlet of the water supply pipe is connected to the water delivery tank above the sealed water tank.

[0015] In a preferred embodiment, the water tank is provided with an outlet pipe at the bottom, and a water valve is provided on the outlet pipe. The outlet of the outlet pipe is connected to a ring pipe inlet installed on the top of the water tank cover via a fire hose.

[0016] In a preferred embodiment, the ring pipe is configured as a circular ring and is installed and fixed on the top of the water tank cover. The top of the ring pipe is provided with a water inlet, which is connected to the water outlet pipe at the bottom of the water tank via a fire hose. Several water injection pipes are provided at the bottom of the ring pipe, with one end of the water injection pipe connected to the ring pipe and the other end passing through the top of the water tank cover and connected to the sealed water tank.

[0017] In a preferred embodiment, a support frame is provided at the bottom of the water tank. The support frame is configured as a frame structure, and the frame extends above the sealed water tank.

[0018] In a preferred embodiment, the wireless acoustic sensors are closely arranged on the top cover of the water tank and the outer wall of the sealed water tank, with at least two groups of four sensors. One group of two sensors is symmetrically arranged on the top of the water tank cover, and another group of two sensors is symmetrically arranged in the middle of the outer wall of the sealed water tank. The wireless acoustic sensors are fixed to the support frame using flexible metal hoses.

[0019] In a preferred embodiment, the hydrophone is installed at the bottom of the water tank base and is arranged inside the sealed water tank. The fiber optic sensor includes a first fiber optic sensor and a second fiber optic sensor. The first fiber optic sensor is installed at the bottom of the water tank base and is arranged in the interlayer between the two cylindrical bodies of the sealed water tank. The second fiber optic sensor is installed on the bottom surface of the sealed water tank.

[0020] An experimental method for simulating the propagation characteristics of turbine discharge noise, based on the aforementioned experimental apparatus for simulating the propagation characteristics of turbine discharge noise, includes the following steps: Step 1: After calculating and selecting the device parameters using the similarity law of water turbines and ensuring that the device passes acceptance, select a flat site with low external noise to arrange the device. Arrange the sealed water tank, water conveyance tank, water delivery tank, water tank base, lower support structure and support frame in place and connect them. Install the water tank top cover, spring lock, shaft, propeller, ring pipe, water pump, motor and water valve in place and test them with water. Step 2: Install the measuring device. First, calibrate each sensor and hydrophone 17. Then, place wireless acoustic sensors near the top surface of the water tank cover and near the outer surface of the middle part of the sealed water tank. Place the first fiber optic sensor in the interlayer between the two cylinders of the sealed water tank through a perforation in the water tank base. Place the second fiber optic sensor with bonding material on the lower surface of the sealed water tank. Install the hydrophone at the bottom of the water tank base and place it inside the sealed water tank. Step 3: Add enough water to the water supply tank, do not fill the cylindrical interlayer of the sealed water tank with any material, fully open the water valve at the bottom of the water delivery tank, start the water pump, and the water in the water supply tank is pumped into the water delivery tank through the water delivery pipe. After entering the water delivery tank, the water enters the ring pipe on the top cover of the water tank through the bottom outlet pipe and fire hose, and then enters the sealed water tank through the bottom water injection pipe. Under the impact of the water, the paddle rotates by itself. After the water entering the sealed water tank does work, it returns to the water supply tank through the outlet pipe at the bottom of the sealed water tank, thus achieving water circulation. Observe the operating status of the device. After the device stabilizes, analyze the measurement effect of each sensor at the device end, and re-check each sensor to normal working condition before ending this step. Step 4: After the measuring device is running correctly, pre-determine the corresponding background noise, then turn on the water pump and repeat Step 3 to make the device run stably. After the data from the analysis end of each sensor is stable, select the duration to be analyzed, record the data once for the duration, and record multiple sets of data under the same working conditions to reduce errors and complete the measurement and recording of the propagation characteristics of the discharge noise under normal working conditions. Step 5: After completing Step 4, start the motor. The motor drives the shaft to rotate, increasing the speed of the propeller. Repeat Step 4 to simulate operation under non-fault conditions and record the propagation characteristics of leakage noise under simulated non-fault conditions. Step 6: Without starting the motor, loosen the spring lock, lift the top cover of the water tank and place it on the support frame for temporary fixation. Replace the impeller with a different shape to simulate operation under fault conditions, including impeller deformation, cracks, scouring and foreign objects. After replacing the impeller, put the top cover of the water tank and its shaft and impeller back into the sealed water tank. Repeat the operation steps in Step 4 and record the leakage noise propagation characteristics under simulated fault conditions. Step 7: Change other variables, such as water valve opening, motor speed, and number of blades, and repeat Steps 4-6 to obtain data under different operating conditions. Complete the recording of the leakage noise propagation characteristics under different operating conditions. After the experiment is completed, use software to perform acoustic processing on the measurement data under normal and abnormal operating conditions on the computer, and classify and establish the corresponding basic database. Step 8: Simulate noise reduction operation. During the equipment installation in Step 1, fill the interlayer between the double-layer cylinders of the sealed water tank with media of different structures, and then measure the background noise. Repeat Step 5 and Step 7 to conduct the experiment, measure the sound pressure level of the leakage noise after passing through different materials, and detect its attenuation degree and noise reduction effect.

[0021] The experimental apparatus and method for simulating the propagation characteristics of turbine discharge noise provided by this invention have the following beneficial effects: 1. This invention focuses on the noise of turbine leakage in the various noises and faults that occur during the operation of hydropower station facilities. By using water flow in a sealed space to drive the blade rotation and motor to control the blade rotation, the possible leakage noise of the turbine during normal operation, emergency operation, and fault operation is simulated and analyzed. Different types of acoustic sensors are placed in different locations to measure the corresponding noise data, and the data is checked or compared with the measurement data of the actual unit. This achieves the expected goal of the effectiveness and analyzability of measuring the leakage noise of the turbine during normal, emergency, and fault operation. 2. By arranging different types of acoustic sensors at different locations and simultaneously comparing the measured data horizontally between the sensors and vertically comparing it with the data from the actual operating unit, the present invention can minimize experimental errors and achieve the goal of making the experimental data representative, effective, and analyzable. 3. The measurement and research method of the device of the present invention is more effective than the traditional measurement ideas and methods. Compared with the traditional method of using vibration signals to analyze the operation of water turbines, the detection speed of sound signals is faster and the accuracy is higher. The measurement positions of the measurement points used are arranged from the original signal water to the volute to the air attenuation, which has a high degree of hierarchy. The research and analysis of the propagation characteristics of the discharge noise is logically strong. 4. The experimental device of this invention uses materials that are closer to the actual materials of water turbines, the water flow is closer to the actual operating path, the blade rotation and circulating water flow are controllable, the blade shape, size and condition can be changed in various ways, and sound and vibration measurements can be performed simultaneously using an integrated sound and vibration analyzer when necessary. The working condition simulation and measurement types are more realistic and diversified, and the obtained data are more authentic, analyzable and representative. 5. Various shapes and types of materials can be filled between the steel cylinders of the experimental device of this invention. The characteristics of noise after attenuation can be measured by adding or changing the position of the sensor, which provides certain reference value for the ecological operation of hydropower stations. 6. Compared with the traditional method of analyzing the operation of water turbines using vibration signals, this invention has a faster detection speed and higher accuracy for acoustic signals. The measurement positions of the measurement points used are attenuated from the original signal water to the volute and then to the air, which has a high degree of hierarchy. The research and analysis of the propagation characteristics of the discharge noise is logically strong. The operating condition simulation and measurement types are more realistic and diversified, and the obtained data is more authentic, analyzable, and representative. 7. This invention also has high flexibility and can adjust the experimental configuration according to actual needs to adapt to the noise characteristics research of different types of water turbines and operating conditions, providing strong support for the optimized design of water turbines and the environmentally friendly operation of hydropower stations. 8. The experimental apparatus of this invention has a clear design concept, simple structure, convenient operation, high controllability of various variables, and obvious experimental results; 9. This invention has a simple structure, is easy to maintain, and has significant cost-effectiveness. It can be widely used in scientific research, teaching, and engineering practice, promoting the further development of turbine noise control technology and contributing to the realization of green and efficient hydropower station operation. Its modular design facilitates maintenance and upgrades, laying a solid foundation for in-depth exploration of turbine noise research. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partial schematic diagram of the assembly of the water tank and water valve of the present invention; Figure 3 This is a partial schematic diagram of the assembly of the rotating shaft and coupling of the present invention; Figure 4 This is a partial schematic diagram of the assembly of the water supply tank and the water outlet pipe of the present invention; Figure 5 This is a partial schematic diagram of the assembly of the water tank top cover, the sealed water tank, and the spring lock of the present invention; Figure 6 This is a schematic diagram of the assembly of the top of the water tank cover of the present invention; Figure 7 This is a schematic diagram showing the arrangement of the wireless acoustic sensor on the top cover of the water tank according to the present invention; Figure 8 This is a schematic diagram showing the arrangement of the wireless acoustic sensor, hydrophone, and fiber optic sensor of the present invention. Figure 9 This is a schematic diagram of the assembly of the rotating shaft and the propeller of the present invention; In the diagram: 1. Water supply pipe; 2. Water tank; 3. Water injection pipe; 4. Water valve; 5. Water supply tank; 6. Water pump; 7. Shaft; 8. Ring pipe; 9. Wireless acoustic sensor; 10. Coupling; 11. Water tank top cover; 12. Spring lock; 13. Water outlet pipe; 14. Sealed water tank; 15. Paddle; 16. Water tank base; 17. Hydrophone; 18. Support structure; 19. Support frame; 20. First fiber optic sensor; 21. Second fiber optic sensor. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1 like Figures 1-9 As shown, an experimental device for simulating the propagation characteristics of discharge noise from a water turbine includes a sealed water tank 14. A rotating device is vertically installed inside the sealed water tank 14, including a rotating shaft 7 and a propeller 15. A ring pipe 8 is installed on the top of the sealed water tank 14, with one end connected to the sealed water tank 14 and the other end connected to a water supply tank 2 via a fire hose. The water supply tank 2 is connected to a water pump 6 of a water supply tank 5 via a water delivery pipe 1. The bottom of the sealed water tank 14 is connected to the water supply tank 5 via an outlet pipe 13. Wireless acoustic sensors 9 are installed on the outside and top of the sealed water tank 14. A hydrophone 17 is also installed inside the sealed water tank 14. Fiber optic sensors are also installed on the body and bottom of the sealed water tank 14. The wireless acoustic sensors 9, hydrophone 17, and fiber optic sensors all have built-in analysis equipment.

[0024] In this embodiment, the sealed water tank 14 is configured as a double-layered metal cylinder with an interlayer between the two layers. A first fiber optic sensor 20 is installed in the interlayer. A water tank base 16 is provided at the bottom of the sealed water tank 14. The water tank base 16 is configured as an annular shape. Lower support structures 18 are evenly distributed around the bottom of the water tank base 16. A water tank top cover 11 is provided at the top of the sealed water tank 14. The water tank top cover 11 and the sealed water tank 14 are connected and fastened together by a spring lock 12. A sealing ring is provided between the water tank top cover 11 and the sealed water tank 14.

[0025] Furthermore, a rotating shaft 7 is rotatably installed in the middle of the water tank top cover 11. The lower end of the rotating shaft 7 is suspended in the air. A motor is fixedly installed on the top of the water tank top cover 11 via a coupling 10. Several paddles 15 are installed inside the sealed water tank 14 at the lower part of the rotating shaft 7.

[0026] Furthermore, the water supply tank 5 is located below the sealed water tank 14. A water outlet pipe 13 is installed at the bottom of the sealed water tank 14. The inlet of the water outlet pipe 13 is connected to the sealed water tank 14, and the outlet is connected to the water supply tank 5. A water pump 6 is installed in the middle of the water supply tank 5. The outlet of the water pump 6 is connected to the inlet of the water supply pipe 1, and the outlet of the water supply pipe 1 is connected to the water delivery tank 2 above the sealed water tank 14.

[0027] Furthermore, the bottom of the water tank 2 is provided with a water outlet pipe, and a water valve 4 is provided on the water outlet pipe. The water outlet of the water outlet pipe is connected to the water inlet of the ring pipe 8 installed on the top of the water tank cover 11 through a fire hose.

[0028] Furthermore, the ring pipe 8 is configured as a circular ring and is installed and fixed on the top of the water tank top cover 11. The top of the ring pipe 8 is provided with a water inlet, which is connected to the water outlet pipe at the bottom of the water supply tank 2 through a fire hose. Several water injection pipes 3 are provided at the bottom of the ring pipe 8. One end of the water injection pipe 3 is connected to the ring pipe 8, and the other end passes through the water tank top cover 11 and is connected to the sealed water tank 14.

[0029] Furthermore, a support frame 19 is provided at the bottom of the water tank 2. The support frame 19 is configured as a frame structure, and the frame extends above the sealed water tank 14.

[0030] Furthermore, the wireless acoustic sensors 9 are closely arranged on the top cover 11 of the water tank and the outer wall of the sealed water tank 14, with at least two sets of four sensors. Two sensors are symmetrically arranged on the top of the top cover 11, and two sensors are symmetrically arranged in the middle of the outer wall of the sealed water tank 14. The wireless acoustic sensors 9 are fixed to the support frame 19 with metal flexible hoses.

[0031] Furthermore, the hydrophone 17 is installed at the bottom of the water tank base 16 and is arranged inside the sealed water tank 14. The fiber optic sensor includes a first fiber optic sensor 20 and a second fiber optic sensor 21. The first fiber optic sensor 20 is installed at the bottom of the water tank base 16 and is arranged in the interlayer between the two cylindrical bodies of the sealed water tank 14. The second fiber optic sensor 21 is installed on the bottom surface of the sealed water tank 14.

[0032] In practical use, the experimental method of using the above-described experimental apparatus to simulate the propagation characteristics of turbine discharge noise includes the following steps: Step 1: After calculating and selecting the device parameters using the similarity law of water turbines and ensuring that the device passes acceptance, select a flat site with low external noise to arrange the device. Arrange the sealed water tank 14, water conveying tank 2, water delivery tank 5, water tank base 16, lower support structure 18 and support frame 19 in place and connect them. Install the water tank top cover 11, spring lock 12, rotating shaft 7, propeller 15, ring pipe 8, water pump 6, motor and water valve 4 in place and test them with water. Step 2: Install the measuring device. First, calibrate each sensor and hydrophone 17. Then, place the wireless acoustic sensor 9 near the upper surface of the water tank top cover 11 and near the outer surface of the middle part of the sealed water tank 14. Place the first fiber optic sensor 20 through a hole in the water tank base 16 in the interlayer between the two cylinders of the sealed water tank 14. Place the second fiber optic sensor 21 with the bonding material on the lower surface of the sealed water tank 14. Install the hydrophone 17 at the bottom of the water tank base 16 and place it inside the sealed water tank 14. Step 3: Add enough water to the water supply tank 5. Do not fill the cylindrical interlayer of the sealed water tank 14 with any material. Fully open the water valve 4 at the bottom of the water supply tank 2. Start the water pump 6. The water in the water supply tank 5 is pumped into the water supply tank 2 through the water supply pipe 1. After entering the water supply tank 2, the water enters the ring pipe 8 of the top cover 11 of the water tank through the bottom outlet pipe and fire hose. Then, it enters the sealed water tank 14 through the bottom water injection pipe 3. Under the impact of the water, the paddle 15 rotates. After the water enters the sealed water tank 14 and does work, it returns to the water supply tank 5 through the outlet pipe 13 at the bottom of the sealed water tank 14, thus achieving water circulation. Observe the operating status of the device. After the device stabilizes, analyze the measurement effect of each sensor at the device end and re-verify each sensor to normal working condition before ending this step. Step 4: After the measuring device is running correctly, measure the background noise in advance. Then turn on the water pump 6 and repeat Step 3 to make the device run stably. After the data from the analysis end of each sensor is stable, select the duration to be analyzed and record the data once for the duration. Record multiple sets of data under the same working conditions to reduce errors and complete the measurement and recording of the propagation characteristics of the discharge noise under normal working conditions. Step 5: After completing Step 4, start the motor. The motor drives the shaft 7 to rotate, increasing the speed of the propeller 15. Repeat Step 4 to simulate operation under non-fault conditions and record the propagation characteristics of leakage noise under simulated non-fault conditions. Step 6: Without starting the motor, loosen the spring lock 12, lift the water tank top cover 11 and place it on the support frame 19 for temporary fixation, replace it with a different shaped propeller 15 to simulate operation under fault conditions, including blade deformation, cracks, scouring and foreign objects, etc. After replacing the propeller 15, put the water tank top cover 11 and its shaft 7 and propeller 15 back into the sealed water tank 14, repeat the operation steps in Step 4, and complete the recording of the leakage noise propagation characteristics under simulated fault conditions; Step 7: Change other variables, such as water valve opening, motor speed, and number of blades, and repeat Steps 4-6 to obtain data under different operating conditions. Complete the recording of the leakage noise propagation characteristics under different operating conditions. After the experiment is completed, use software to perform acoustic processing on the measurement data under normal and abnormal operating conditions on the computer, and classify and establish the corresponding basic database. Step 8: Simulate noise reduction operation. During the equipment installation in Step 1, fill the interlayer between the double-layer cylinders of the sealed water tank 14 with media of different structures, and then measure the background noise. Repeat Step 5 and Step 7 to conduct the experiment, measure the sound pressure level of the leakage noise after passing through different materials, and detect its attenuation degree and noise reduction effect.

[0033] Example 2 In another preferred embodiment, based on Embodiment 1 above, background noise is measured under conditions including but not limited to the following: A. Under waterless conditions, neither the motor on the top of the water tank cover 11 nor the water pump 6 in the water supply tank 5 will operate; B. Under waterless conditions, the motor on top of the water tank cover 11 runs, while the water pump 6 in the water supply tank 5 does not run; C. When there is water, the motor on top of the water tank cover 11 does not run, and the water pump 6 in the water supply tank 5 runs. D. Under water conditions, the motor on top of the water tank cover 11 and the water pump 6 in the water supply tank 5 are both running.

[0034] After measuring and recording the background noise, proceed with the following experimental steps: First, fill the water tank 5 with about 4 / 5 of its volume. Do not fill the interlayer between the double-layered cylinders of the sealed water tank 14 with any material. Fully open the water valve 4 at the bottom of the water tank 2 and turn on the water pump 6 to pump water into the water tank 2.

[0035] Without turning on the motor controlling the top propeller 15, and with the propeller 15 size set to default, start measuring and recording measurement data. After the data fluctuations stabilize, record the data (time-averaged data) from sensors 9, 17, and 20 every 10 to 20 seconds. Record three sets of data under the same operating conditions to reduce experimental errors.

[0036] Then, the top motor is turned on to increase the speed of the propeller by 1 / 10 to 1 / 5 to simulate the overload operation of the turbine. The data fluctuations are observed. After stabilization, the data (time-averaged data) of the wireless acoustic sensor 9, the first fiber optic sensor 20 and the second fiber optic sensor 21 of the hydrophone 17 are recorded every 10 to 20 seconds. Three sets of data are recorded under the same conditions to reduce experimental error.

[0037] Release the spring lock 12, place the water tank top cover 11 on the support frame 19 for temporary fixation, and then change the shape of the propeller 15 to simulate faults, including but not limited to: simulating blade deformation by twisting the propeller 15; simulating blade cracking (minor missing parts or cracks) by cutting the propeller 15; simulating pitting caused by long-term erosion of blades by sand or foreign objects by making the surface of the propeller 15 pitted; and simulating common faults such as foreign objects entering the (volute) rotor chamber and not being discharged in time by adding some foreign objects.

[0038] By changing other variables, such as water valve opening, motor speed, and number of blades, the above operation steps are repeated to obtain data under different operating conditions. Then, the measurement data under normal and fault conditions are processed by noise spectrum separation using relevant software to obtain the noise characteristics under different faults. By repeatedly controlling the operating data under the same fault under normal or emergency operating conditions, but with different other variables, a basic database for normal and emergency operating conditions is established. Data from real units are added for verification or comparison to expand the database and provide a data foundation for intelligent fault identification of the turbine in the later stage.

[0039] Example 3 In another preferred embodiment, based on the above embodiment 1, such as Figure 1 As shown in the basic operation embodiments 1 and 2, during equipment installation, different structural media, such as solid or honeycomb foam boards, sandwich gypsum boards, asbestos boards, plastic boards, etc., are filled in the interlayer between the double-layer cylinders of the sealed water tank 14. Then, the background noise is measured to reduce errors. The sound pressure level of the discharge noise after passing through different materials is measured to detect their different attenuation degrees and noise reduction effects, providing certain reference value for the ecological operation of the hydropower station.

[0040] In a preferred embodiment, the sealed water tank 14 is configured as a double-layered metal cylinder with an interlayer between the two layers. A first fiber optic sensor 20 is installed in the interlayer. A water tank base 16 is provided at the bottom of the sealed water tank 14, and the water tank base 16 is configured as a ring. Lower support structures 18 are evenly distributed around the bottom of the water tank base 16. A water tank top cover 11 is provided at the top of the sealed water tank 14. The water tank top cover 11 and the sealed water tank 14 are connected and fastened together by a spring lock 12. A sealing ring is provided between the water tank top cover 11 and the sealed water tank 14. The above configuration can effectively ensure the sealing performance of the sealed water tank 14. At the same time, the first fiber optic sensor 20 can monitor the noise changes in the interlayer in real time to ensure accurate measurement data. The water tank base 16 and the lower support structure 18 provide stable support and enhance the stability of the overall structure.

[0041] In a preferred embodiment, a rotating shaft 7 is rotatably mounted in the middle of the water tank top cover 11, with the lower end of the rotating shaft 7 suspended in the air. A motor is fixedly mounted on the top of the water tank top cover 11 via a coupling 10. Several paddles 15 are installed inside the sealed water tank 14 at the lower part of the rotating shaft 7. With the above configuration, driven by the motor, the rotating shaft 7 drives the paddles 15 to rotate inside the sealed water tank 14, forming a water circulation, effectively simulating the actual operating state of a water turbine.

[0042] In a preferred embodiment, the water supply tank 5 is positioned below the sealed water tank 14. A water outlet pipe 13 is installed at the bottom of the sealed water tank 14. The inlet of the water outlet pipe 13 is connected to the sealed water tank 14, and the outlet is connected to the water supply tank 5. A water pump 6 is installed in the middle of the water supply tank 5. The outlet of the water pump 6 is connected to the inlet of the water supply pipe 1, and the outlet of the water supply pipe 1 is connected to the water conveying tank 2 above the sealed water tank 14. With the above configuration, the water in the water supply tank 5 can be automatically drawn to the water supply pipe 1 through the operation of the water pump 6, and then returned to the sealed water tank 14 through the water conveying tank 2, forming a closed-loop water circulation to ensure continuous water supply to the system.

[0043] In the preferred embodiment, the bottom of the water tank 2 is provided with a water outlet pipe, and a water valve 4 is provided on the water outlet pipe. The outlet of the water outlet pipe is connected to the inlet of the ring pipe 8 installed on the top of the water tank cover 11 through a fire hose. The above configuration ensures that, according to experimental needs, by opening the water valve 4, the water in the water tank 2 can quickly flow into the fire hose through the water outlet pipe, and be evenly distributed around the top of the water tank cover 11 through the ring pipe 8, so as to achieve efficient and uniform water supply for the rotating device to operate.

[0044] In the preferred embodiment, the ring pipe 8 is configured as a circular ring and is installed and fixed on the top of the water tank cover 11. The top of the ring pipe 8 is provided with a water inlet, which is connected to the water outlet pipe at the bottom of the water supply tank 2 through a fire hose. Several water injection pipes 3 are provided at the bottom of the ring pipe 8. One end of the water injection pipe 3 is connected to the ring pipe 8, and the other end passes through the water tank cover 11 and is connected to the sealed water tank 14. The above configuration realizes the efficient and uniform distribution of water from the water supply tank 2 to the sealed water tank 14, ensuring a sufficient and stable water supply when the rotating device is running with water. At the same time, the circular ring pipe 8 design enhances the stability of the structure, facilitates installation and maintenance, and ensures uniform water supply to the rotating device, more realistically restoring and simulating the operating state of the water turbine, thereby further ensuring the authenticity and validity of the experimental data.

[0045] In a preferred embodiment, a support frame 19 is provided at the bottom of the water tank 2. The support frame 19 is configured as a frame structure, with the frame extending above the sealed water tank 14. This configuration aims to ensure the stable installation of the water tank 2, while optimizing the spatial layout through the frame extension design, resulting in a compact and efficient overall structure. The bottom of the frame maintains an appropriate gap with the sealed water tank 14 to avoid direct contact, which is beneficial for maintaining the stability and safety of the system. At the same time, the support frame 19 extending above the sealed water tank 14 provides placement space for the rotating device and the water tank top cover 11 during hoisting and maintenance.

[0046] In the preferred embodiment, the wireless acoustic sensors 9 are closely arranged on the top cover 11 of the water tank and the outer wall of the sealed water tank 14, with at least two sets of four sensors. One set of two sensors is symmetrically arranged on the top of the top cover 11, and another set of two sensors is symmetrically arranged in the middle of the outer wall of the sealed water tank 14. The wireless acoustic sensors 9 are fixed to the support frame 19 using flexible metal hoses. This arrangement ensures comprehensive monitoring of the liquid level and abnormal sounds inside the water tank, improving monitoring accuracy and response speed. The flexible metal hose design enhances installation flexibility and durability, adapts to different working conditions, and ensures long-term stable operation of the system.

[0047] In a preferred embodiment, the hydrophone 17 is installed at the bottom of the water tank base 16 and is disposed inside the sealed water tank 14. The fiber optic sensor includes a first fiber optic sensor 20 and a second fiber optic sensor 21. The first fiber optic sensor 20 is installed at the bottom of the water tank base 16 and is disposed in the interlayer between the two cylindrical bodies of the sealed water tank 14. The second fiber optic sensor 21 is installed on the bottom surface of the sealed water tank 14. The above arrangement aims to achieve multi-dimensional and high-precision monitoring. The hydrophone 17 directly monitors the dynamics of the water body and noise sources, while the fiber optic sensors, through their arrangement in different positions (interlayer and bottom), capture complete information on water level and noise changes, together forming an efficient and reliable monitoring network.

[0048] In summary, the experimental apparatus and method for simulating the propagation characteristics of turbine discharge noise provided by this invention can simulate the noise situation of turbine discharge from multiple perspectives and under multiple operating conditions by controlling variables such as inflow and outflow water flow, motor speed, and changing different blades. It can also simulate the noise reduction effect of turbine discharge by filling the interlayer with different materials. This invention simulates the operation of a turbine under normal and abnormal operating conditions (including fault conditions), using wireless acoustic sensors, fiber optic acoustic sensors, and hydrophones to measure discharge noise and analyze its propagation characteristics after attenuation through the wall. Using this invention, the propagation and attenuation characteristics of turbine discharge noise can be studied, providing data reference for the acoustic diagnosis of turbine faults and also offering certain reference value for the ecological operation of hydropower stations. The significant advantage of this invention is its ability to accurately simulate the noise of a turbine discharge. This invention studies the propagation characteristics of discharge noise under different operating conditions, providing reliable experimental data and theoretical basis for turbine noise control, optimization design, and environmental impact assessment. The experimental device is compact, easy to operate, and highly accurate, significantly reducing research costs, shortening the research cycle, and improving research efficiency. Furthermore, by adjusting the operating parameters of the simulated turbine body, the output characteristics of the noise source simulation system, and the boundary conditions of the noise propagation channel, this invention can flexibly simulate noise propagation characteristics under various complex operating conditions, providing strong support for the innovation and development of turbine noise control technology. Moreover, the experimental device features a modular structure, facilitating upgrades and maintenance. In the future, it can integrate more advanced sensors and analysis technologies to meet the needs of higher-precision noise research and complex environment simulation, propelling turbine noise control technology to new heights.

Claims

1. An experimental method for simulating the propagation characteristics of discharge noise from a water turbine, characterized in that, The experimental setup based on the propagation characteristics of turbine discharge noise includes the following steps: Step 1: After calculating and selecting the device parameters using the similarity law of water turbines and making and accepting the device, select a flat site with low external noise to arrange the device. Arrange the sealed water tank (14), water conveying tank (2), water delivery tank (5), water tank base (16), lower support structure (18) and support frame (19) in place and connect them. Install the water tank top cover (11), spring lock (12), rotating shaft (7), propeller (15), ring pipe (8), water pump (6), motor and water valve (4) in place and test them with water. Step 2: Install the measuring device. First, check each sensor and hydrophone (17). Then, place the wireless acoustic sensor (9) near the upper surface of the water tank top cover (11) and near the outer surface of the middle part of the sealed water tank (14). Place the first fiber optic sensor (20) through the perforation of the water tank base (16) in the interlayer between the double cylinders of the sealed water tank (14). Place the second fiber optic sensor (21) with the bonding material on the lower surface of the sealed water tank (14). Install the hydrophone (17) at the bottom of the water tank base (16) and place it inside the sealed water tank (14). Step 3: Add enough water to the water supply tank (5), do not fill the cylindrical interlayer of the sealed water tank (14) with material, fully open the water valve (4) at the bottom of the water supply tank (2), start the water pump (6), the water in the water supply tank (5) is pumped into the water supply tank (2) through the water supply pipe (1) after entering the water supply tank (2), and then enters the ring pipe (8) of the top cover (11) of the water tank through the bottom outlet pipe and fire hose, and then enters the sealed water tank (14) through the bottom water injection pipe (3). Under the impact of the water, the paddle (15) rotates by itself. After the water in the sealed water tank (14) does work, it returns to the water supply tank (5) through the outlet pipe (13) at the bottom of the sealed water tank (14) to achieve water circulation. Observe the operating status of the device. After the device is stable, analyze the measurement effect of each sensor at the device end, and re-check each sensor to normal working status before ending this step. Step 4: After debugging the measuring device to ensure it is running correctly, measure the background noise in advance, then turn on the water pump (6), repeat Step 3 to make the device run stably, and after the data from the analysis end of each sensor is stable, select the duration to be analyzed, record the data once for the duration, record multiple sets of data under the same working conditions to reduce errors, and complete the measurement and recording of the propagation characteristics of the leakage noise under normal working conditions. Step 5: After Step 4 is completed, start the motor. The motor drives the shaft (7) to rotate, increasing the speed of the propeller (15). Repeat Step 4 to simulate operation under non-fault conditions and record the propagation characteristics of leakage noise under simulated non-fault conditions. Step 6: Without starting the motor, loosen the spring lock (12), lift the water tank top cover (11) and place it on the support frame (19) for temporary fixation. Replace the impeller (15) with a different shape to simulate operation under fault conditions, including impeller deformation, cracks, scouring and foreign objects. After replacing the impeller (15), put the water tank top cover (11) and its shaft (7) and impeller (15) back into the sealed water tank (14). Repeat the operation steps in Step 4 and complete the recording of the leakage noise propagation characteristics under simulated fault conditions. Step 7: Change other variables, such as water valve opening, motor speed, and number of blades, and repeat Steps 4-6 to obtain data under different operating conditions. Complete the recording of the leakage noise propagation characteristics under different operating conditions. After the experiment is completed, use software to perform acoustic processing on the measurement data under normal and abnormal operating conditions on the computer, and classify and establish the corresponding basic database. Step 8: Simulate noise reduction operation. When the equipment is installed in Step 1, fill the interlayer between the double-layer cylinders of the sealed water tank (14) with media of different structures, and then measure the background noise. Repeat Step 5 and Step 7 to conduct the experiment, measure the sound pressure level of the leakage noise after passing through different materials, and detect its attenuation degree and noise reduction effect. An experimental device for simulating the propagation characteristics of discharge noise of a water turbine includes a sealed water tank (14), a rotating device is vertically installed inside the sealed water tank (14), the rotating device includes a rotating shaft (7) and a paddle (15), a ring pipe (8) is provided on the top of the sealed water tank (14), one end of the ring pipe (8) is connected to the sealed water tank (14), and the other end is connected to the water supply tank (2) through a fire hose. The water supply tank (2) is connected to the water pump (6) of the water supply tank (5) through a water supply pipe (1), and the bottom of the sealed water tank (14) is connected to the water supply tank (5) through a water outlet pipe (13). Wireless acoustic sensors (9) are provided on the outside and top of the sealed water tank (14), a hydrophone (17) is also provided in the sealed water tank (14), and fiber optic sensors are also provided on the body and bottom of the sealed water tank (14). The wireless acoustic sensor (9), the hydrophone (17) and the fiber optic sensor are all equipped with their own analysis equipment.

2. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The sealed water tank (14) is configured as a double-layer metal cylinder with an interlayer between the two layers. A first fiber optic sensor (20) is installed in the interlayer. A water tank base (16) is installed at the bottom of the sealed water tank (14). The water tank base (16) is configured as a ring. A lower support structure (18) is evenly distributed around the bottom of the water tank base (16). A water tank top cover (11) is installed on the top of the sealed water tank (14). The water tank top cover (11) and the sealed water tank (14) are connected and fastened together by a spring lock (12). A sealing ring is installed between the water tank top cover (11) and the sealed water tank (14).

3. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: A rotating shaft (7) is rotatably installed in the middle of the top cover (11) of the water tank. The lower end of the rotating shaft (7) is suspended in the air. A motor is fixed to the top of the top cover (11) of the water tank via a coupling (10). Several paddles (15) are installed in the lower part of the rotating shaft (7) inside the sealed water tank (14).

4. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The water supply tank (5) is located below the sealed water tank (14). A water outlet pipe (13) is installed at the bottom of the sealed water tank (14). The inlet of the water outlet pipe (13) is connected to the sealed water tank (14), and the outlet is connected to the water supply tank (5). A water pump (6) is installed in the middle of the water supply tank (5). The outlet of the water pump (6) is connected to the inlet of the water supply pipe (1), and the outlet of the water supply pipe (1) is connected to the water conveying tank (2) above the sealed water tank (14).

5. The experimental apparatus for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The water tank (2) is equipped with a water outlet pipe at the bottom and a water valve (4) on the water outlet pipe. The water outlet of the water outlet pipe is connected to the water inlet of the ring pipe (8) installed on the top of the water tank cover (11) through a fire hose.

6. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The ring pipe (8) is set in a circular shape and is installed and fixed on the top of the water tank cover (11). The top of the ring pipe (8) is provided with a water inlet and is connected to the water outlet pipe at the bottom of the water tank (2) through a fire hose. Several water injection pipes (3) are provided at the bottom of the ring pipe (8). One end of the water injection pipe (3) is connected to the ring pipe (8), and the other end passes through the top of the water tank cover (11) and is connected to the sealed water tank (14).

7. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The bottom of the water tank (2) is provided with a support frame (19), which is a frame structure and extends above the sealed water tank (14).

8. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The wireless acoustic sensors (9) are closely arranged on the top cover (11) of the water tank and the outer wall of the sealed water tank (14). At least two sets of four are arranged, with one set of two symmetrically arranged on the top of the top cover (11) and one set of two symmetrically arranged on the middle of the outer wall of the sealed water tank (14). The wireless acoustic sensors (9) are fixed on the support frame (19) with metal flexible hoses.

9. The experimental method for simulating the propagation characteristics of turbine discharge noise according to claim 1, characterized in that: The hydrophone (17) is installed at the bottom of the water tank base (16) and is arranged inside the sealed water tank (14). The fiber optic sensor includes a first fiber optic sensor (20) and a second fiber optic sensor (21). The first fiber optic sensor (20) is installed at the bottom of the water tank base (16) and is arranged in the interlayer between the double cylinders of the sealed water tank (14). The second fiber optic sensor (21) is installed on the bottom surface of the sealed water tank (14).

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