A method for suppressing pressure pulsation in a water turbine based on synergistic jet water supply

Abstract

This invention discloses a method for suppressing pressure pulsation in hydraulic turbines based on synergistic jet water supply, relating to the field of hydraulic machinery flow control and operational stability technology. The invention first modifies the target turbine by adding a top cover water supply channel and a main shaft center hole water supply channel. Then, it conducts operating condition tests on the target turbine to analyze and obtain the target load operating range. Based on this target load operating range, synergistic water supply tests are performed on the target turbine to further analyze and obtain the optimal combination of synergistic water supply parameters within the target load operating range. Finally, water is supplied to the target turbine based on the target load operating conditions and the optimal combination of synergistic water supply parameters. The synergistic water supply proposed in this invention comprehensively suppresses pressure pulsation from the bladeless region, runner region to the draft tube region without significantly reducing turbine output and efficiency.

Description

Technical Field

[0001] This invention relates to the field of hydraulic machinery flow control and operational stability technology, specifically to a method for suppressing pressure pulsation in a water turbine based on synergistic jet water replenishment. Background Technology

[0002] When existing mixed-flow turbines operate at partial loads deviating from their optimal operating conditions, a significant velocity circulation is generated at the runner outlet, leading to the formation of a spiral vortex band within the draft tube and inducing low-frequency pressure pulsations. Simultaneously, dynamic and static interference at the runner inlet also generates high-frequency pulsations. These pressure pulsations exacerbate unit vibration, thereby affecting operational safety and stability. Therefore, developing a method to suppress turbine pressure pulsations is crucial.

[0003] Existing technologies still have some shortcomings in suppressing pressure pulsations in hydraulic turbines. Specifically: While existing top cover water supply can improve flow conditions between the guide vanes and the runner and suppress blade passage vortices, its effect is mainly concentrated in the guide vane and runner regions, with limited suppression of the draft tube vortex band. Existing main shaft center hole water supply can directly weaken the draft tube vortex core, but it is insufficient in improving the flow pattern in the runner region. Therefore, no single water supply method can comprehensively suppress pressure pulsations from the bladeless region to the entire draft tube flow path. Summary of the Invention

[0004] To address the aforementioned technical shortcomings, the present invention aims to provide a method for suppressing pressure pulsation in water turbines based on synergistic jet water replenishment.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides a method for suppressing pressure pulsation in a water turbine based on synergistic jet water supply, including: Step 1, modifying the target water turbine by adding a top cover water supply channel and a main shaft center hole water supply channel.

[0006] Step 2: Determine the operating characteristic parameters of the target turbine and the corresponding acquisition devices, and then conduct operating condition tests on the target turbine to analyze and obtain the target load operating condition range of the target turbine.

[0007] Step 3: Conduct coordinated water replenishment tests on the target turbine based on the target load operating range, and then analyze and obtain the optimal combination of coordinated water replenishment parameters for the target turbine within the target load operating range.

[0008] Step 4: Based on the target load conditions and the optimal combination of coordinated water replenishment parameters, replenish water to the target turbine.

[0009] The beneficial effects of the present invention are as follows: 1. The synergistic water replenishment proposed in the present invention comprehensively suppresses pressure pulsation from the bladeless zone, the runner zone to the tailrace zone without significantly reducing the turbine output and efficiency.

[0010] 2. Compared with single top cover water replenishment, the synergistic water replenishment proposed in this invention further reduces the low-frequency pulsation amplitude in the bladeless area from 0.0024 to 0.001, and the high-frequency pulsation is more significantly suppressed.

[0011] 3. Compared with water replenishment through a single spindle center hole, the synergistic water replenishment proposed in this invention results in a smaller increase in low-frequency pulsation at the center measuring point of the tailrace pipe inlet section, a larger decrease in low-frequency pulsation near the wall of the elbow section, and the elimination of high-frequency residual pulsation.

[0012] 4. The synergistic water replenishment proposed in this invention makes the radial distribution of velocity circulation at the turbine outlet section more gradual, avoiding the high circulation zone near the wall caused by single top cover water replenishment, and reducing wall shear loss and instability factors.

[0013] 5. The large-scale continuous vortex zone inside the tailrace pipe is broken into smaller vortex structures, resulting in a smoother pressure distribution at each elevation section and effectively reducing unit vibration. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the implementation steps of the method of the present invention.

[0016] Figure 2 This is a schematic diagram of water replenishment for the top cover of the turbine, the target of this invention, where Q1 is the location of the water injection hole.

[0017] Figure 3 This is a schematic diagram of water replenishment to the central hole of the main shaft of the turbine, which is the target of this invention, where Q is the position of the central hole of the main shaft.

[0018] Figure 4 This is a comparison of the vorticity cloud map and velocity vector map of the bladeless region under the following embodiments of the present invention: no water replenishment, single top cover water replenishment, and coordinated water replenishment.

[0019] Figure 5 This is a comparison diagram of the runner blade passage vortex distribution under the following embodiments of the present invention: no water replenishment, single top cover water replenishment, and coordinated water replenishment scheme.

[0020] Figure 6 This is a cloud map comparing the circulation velocity at the runner outlet section under the following scenarios in this invention: no water replenishment, single top cover water replenishment, and coordinated water replenishment.

[0021] Figure 7This is a comparison cloud map of the tailrace vortex band and cross-sectional pressure under the following schemes in the embodiments of the present invention: no water replenishment, single top cover water replenishment, and coordinated water replenishment. AA, BB, and CC represent the cross-sections of the straight conical section of the tailrace pipe with radii of 1.1D1, 1.2D1, and 1.3D1, respectively, where D1 is the maximum diameter of the impeller.

[0022] Figure 8 The frequency domain diagrams of pressure pulsation at each monitoring point in the leaf area, impeller area and tailrace pipe area of ​​the embodiment of the present invention are compared under the following schemes: no water replenishment, single top cover water replenishment and coordinated water replenishment. Among them, (a) GV4, (b) GV6, (c) RU7, (d) RU9, (e) TU1, (f) TU2, (g) TU4 and (h) TU5 are the numbers of each monitoring point. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Reference Figure 1 As shown, the present invention provides a method for suppressing pressure pulsation in a water turbine based on synergistic jet water supply, including: Step 1, modifying the target water turbine by adding a top cover water supply channel and a main shaft center hole water supply channel.

[0025] Reference Figure 2 and Figure 3 As shown, in a specific example, the modification of the target turbine by adding a top cover water supply channel and a main shaft center hole water supply channel is as follows: ST21, several water injection holes are evenly distributed along the circumference of the top cover of the target turbine, wherein the axis of each water injection hole is perpendicular to the water inlet edge of the turbine blade, thereby forming the top cover water supply channel.

[0026] It should be noted that when several water injection holes are arranged along the circumference of the target turbine top cover, the number of water injection holes should be at least 6, and preferably 14.

[0027] It should also be noted that the axis of each water injection hole is perpendicular to the water inlet edge of the rotating blade, thereby ensuring that the water injection jet is directed towards the blade passage vortex generation area.

[0028] ST22. Use the original main shaft center hole of the target turbine as the main shaft center hole water supply channel, and set the outlet of the main shaft center hole water supply channel at the center of the tailrace pipe inlet at the lower end of the main shaft. At the same time, install a flow stabilizer or flow equalization hood at the outlet to form the main shaft center hole water supply channel.

[0029] ST23. Finally, install a top cover water supply device and connect it to the top cover water supply channel. Install a spindle center hole water supply device and connect it to the spindle center hole water supply channel. Then, connect the top cover water supply device and the spindle center hole water supply device to the coordinated control unit for electrical control.

[0030] It should be noted that the top cover water supply device consists of components such as an external high-pressure water supply main pipe, a flow regulating valve, a solenoid on / off valve, a ring distribution main pipe, multiple branch pipes, circumferentially distributed water injection nozzles (water injection holes), sealing flanges, and pressure monitoring instruments.

[0031] The spindle center channel water supply device consists of components such as an upper high-pressure water supply pipeline, an electrically controlled on / off valve, and a flow throttling adjustment component.

[0032] Step 2: Determine the operating characteristic parameters of the target turbine and the corresponding acquisition devices, and then conduct operating condition tests on the target turbine to analyze and obtain the target load operating condition range of the target turbine.

[0033] In a specific example, the operating condition characteristic parameters include pressure pulsation data at each preset position of the target turbine, frame vibration amplitude and vibration frequency, the swing value and swing fluctuation of each bearing position of the main shaft, the radial distribution data of velocity circulation at the runner outlet section, the flow rate through the turbine, and the active power output; the acquisition devices include a power plant computer monitoring system, a pressure pulsation sensor, a vibration sensor, a main shaft swing sensor, a flow acquisition device, and a power output acquisition device.

[0034] It should be noted that the pressure pulsation data includes pressure time-domain data and pressure frequency-domain data.

[0035] In a specific example, the process of conducting the operating condition test on the target turbine is as follows: ST41, keep the net water head of the target turbine running at the unit's design operating head, and set up each data acquisition device and unify the data acquisition time axis of each data acquisition device.

[0036] Specifically, the preset locations include the bladeless zone of the target turbine, the runner inlet and outlet, the straight conical section of the draft tube, and the elbow section of the draft tube.

[0037] ST42. Obtain the rated flow rate of the target turbine from the technical manual, and then set various uniform gradient load conditions based on the rated flow rate. For any load condition, after the target turbine has been running under that load condition for a preset time, collect the operating characteristic parameters of the target turbine through various acquisition devices.

[0038] It should be noted that each uniform gradient load condition covers the load condition range obtained by reducing the rated flow by 80%. For example, if the rated flow is W, then the load condition range is [20%W, W]. The specific gradient value is determined by the relevant personnel. The smaller the gradient value, the more accurate the test results.

[0039] It should be noted that the preset duration is the minimum duration required for the target turbine's flow rate, output, and pressure signals to fluctuate by less than or equal to 0.5% for 3 minutes.

[0040] ST43. Following the steps in ST42, conduct operating condition tests on the target turbine under various load conditions.

[0041] In a specific example, the analysis obtains the target load operating range of the target turbine. The specific process is as follows: ST51, extract the pressure pulsation data at each preset position of the target turbine under each load condition from the operating condition characteristic parameters obtained from ST41-ST43 tests, perform Fourier transform on the pressure pulsation data, and then decompose it to obtain the full-band pulsation amplitude and pulsation main frequency at each position of the target turbine under each load condition.

[0042] ST52. Obtain the turbine rotation frequency of the target turbine from the technical manual. When the pulsating main frequency is ≤0.6 times the turbine rotation frequency, it is defined as low-frequency pulsation. When the main frequency is ≥10 times the turbine rotation frequency, it is defined as high-frequency pulsation. Then, extract the peak amplitude of low-frequency pulsation and peak amplitude of high-frequency pulsation and normalize them. Record the load condition intervals corresponding to the normalized low-frequency pulsation amplitude ≥0.0014 and high-frequency pulsation amplitude ≥0.0095 as the primary target load condition intervals.

[0043] It should be noted that the low-frequency pulsation peak amplitude and the high-frequency pulsation peak amplitude are then extracted and normalized. The normalization process is as follows: the low-frequency pulsation peak amplitude is divided by the net water head; the high-frequency pulsation peak amplitude is divided by the net water head.

[0044] ST53. From the operating condition characteristic parameters obtained from ST41-ST43 tests, extract the radial distribution data of velocity circulation at the runner outlet section, calculate the velocity circulation variation coefficient at the runner outlet section, and then record each load condition corresponding to the variation coefficient > 0.35 as the target load condition.

[0045] It should be noted that the calculation process of the velocity circulation coefficient of variation is as follows: For the radial distribution data of velocity circulation at the runner outlet section collected under any load condition, calculate the average value and standard deviation of the radial distribution data of velocity circulation at the runner outlet section, and divide the standard deviation of velocity circulation by the average value of velocity circulation to obtain the velocity circulation coefficient of variation.

[0046] ST54. From the operating condition characteristic parameters obtained from ST41-ST43 tests, extract the bearing spindle runout amplitude and top cover vibration amplitude of the target turbine under each load condition. Then, find the total bearing clearance of the target turbine from the technical manual. Finally, record the corresponding load condition intervals when the bearing spindle runout amplitude is ≥0.7 times the total bearing clearance or the top cover vibration amplitude is >90um as the primary target load condition intervals.

[0047] It should be noted that when the double amplitude of the bearing main shaft runout is ≥0.7 times the total bearing clearance, or the double amplitude of the top cover vibration is >90μm, the main shaft runout and frame vibration of the target turbine exceed the standard.

[0048] ST55. Integrate the primary target load condition intervals in ST52 and ST54 to obtain the target load condition interval.

[0049] In a specific example, the target load operating range is 60%-80% of the target turbine's rated flow.

[0050] Step 3: Conduct coordinated water replenishment tests on the target turbine based on the target load operating range, and then analyze and obtain the optimal combination of coordinated water replenishment parameters for the target turbine within the target load operating range.

[0051] In a specific example, the coordinated water replenishment test of the target turbine based on the target load operating range is carried out as follows: ST71, keep the net water head of the target turbine running at the unit's design operating head, and deploy each acquisition device to unify the acquisition time axis of each acquisition device.

[0052] ST72. Set up various uniform gradient test conditions based on the target load condition range, and obtain various coordinated water replenishment parameter combinations according to the preset gradient cross settings. The water replenishment parameter combinations include the top cover water replenishment flow rate and the main shaft center hole water replenishment flow rate.

[0053] ST73. For any test condition, the target turbine is sequentially replenished with water using various combinations of coordinated water replenishment parameters. After the target turbine has been running for a preset time, the operating condition characteristic parameters of the target turbine are collected by various acquisition devices. Based on this, the corresponding operating condition characteristic parameters of the target turbine after replenishing water with various combinations of coordinated water replenishment parameters under the test condition are obtained.

[0054] ST74 and ST73 are repeated. For each test condition, the coordinated water replenishment parameter combination is used to conduct the coordinated water replenishment test. Based on this test, the corresponding operating condition characteristic parameters of each coordinated water replenishment parameter combination after water replenishment to the target turbine under each test condition are obtained.

[0055] In a specific example, the analysis yields the optimal combination of coordinated water replenishment parameters for the target turbine within the target load operating range. The specific process is as follows: the coordinated water replenishment parameter combinations obtained from the ST71-ST74 tests are normalized to the corresponding operating characteristic parameters of the target turbine after water replenishment.

[0056] It should be noted that the rated operating condition characteristic parameters are obtained from the technical manual of the target turbine. The absolute value of the difference between each operating condition characteristic parameter and each rated operating condition characteristic parameter is divided by the corresponding rated operating condition characteristic parameter, and the operating condition characteristic parameters are then normalized accordingly.

[0057] The normalized operating condition characteristic parameters are weighted and summed to obtain the operating condition stability coefficient. Based on this, the operating condition stability coefficient of the target turbine corresponding to each combination of coordinated water supply parameters under each test condition is calculated, denoted as . Where i and j represent the test condition number and the combined water replenishment parameter number, respectively, and both i and j are positive integers. Then, according to the calculation formula: The comprehensive operating condition stability coefficient corresponding to the target load operating condition range for each combination of coordinated water replenishment parameters is calculated, where I is the total number of test operating conditions. The combination of coordinated water replenishment parameters corresponding to the minimum comprehensive operating condition stability coefficient is denoted as the optimal combination of coordinated water replenishment parameters.

[0058] It should be noted that when the normalized operating condition characteristic parameters are weighted and summed, the weights of each data point in the operating condition characteristic parameters are equal, and the sum is 1.

[0059] It should also be noted that the smaller the comprehensive operating condition stability coefficient, the lower the dispersion of the unit's pressure pulsation amplitude, vibration swing, and velocity circulation, the smaller the hydraulic performance loss, and the better the unit's overall operating stability.

[0060] In a specific example, the optimal coordinated water supply parameter combination is as follows: the top cover water supply flow rate is 2% of the target turbine's rated flow rate, and the main shaft center hole water supply flow rate is 3% of the target turbine's rated flow rate.

[0061] Step 4: Based on the target load conditions and the optimal combination of coordinated water replenishment parameters, replenish water to the target turbine.

[0062] In a specific example, the process of replenishing water to the target turbine based on the target load condition and optimal coordinated jet water replenishment parameters is as follows: During the operation of the target turbine, the real-time load condition of the target turbine is monitored, and the real-time load condition of the target turbine is compared with the target load condition range. When the real-time load condition of the target turbine reaches the target load condition range, the top cover water replenishment device and the main shaft center hole water replenishment device are simultaneously activated through the coordinated control unit. The top cover water replenishment device replenishes water to the target turbine at 2% of the rated flow rate of the target turbine through the top cover water replenishment channel, and the main shaft center hole water replenishment device replenishes water to the target turbine at 3% of the rated flow rate of the target turbine through the main shaft center hole water replenishment channel, thus simultaneously replenishing water to the target turbine.

[0063] It should be noted that after coordinated water replenishment, the low-frequency pressure pulsation amplitude at 0.49 times the rotational frequency in the bladeless zone of the target turbine dropped to below 0.001, and the peak-to-peak value of the pressure pulsation on the wall of the draft tube elbow section decreased by more than 50%.

[0064] For example, when the target turbine is a mixed-flow turbine, its rated flow rate Qn = 316 m³ / s. 3 / s, rated output 250MW, under load condition Case 3: flow rate is 0.7Qn, output is about 95.4MW, coordinated jet water replenishment is carried out: (1) Top cover water replenishment setting: 14 water injection holes are evenly arranged in the circumferential direction of the top cover, with a hole diameter of 8cm and a total water injection volume of 0.02Qn. The water injection direction is perpendicular to the water inlet side of the impeller blade. (2) Main shaft center hole water replenishment setting: water is injected into the center area of ​​the tailwater pipe inlet using the main shaft center hole (diameter 30cm), with a water injection volume of 0.03Qn. (3) Both water replenishment channels are opened at the same time and run continuously.

[0065] After the water replenishment was completed, the target turbine was monitored and found to have the following external characteristics: the unit output was 95.5MW after the coordinated water replenishment, and the efficiency changed by less than 0.2% compared with that before the water replenishment.

[0066] Reference Figure 4 As shown, the flow field in the bladeless region is as follows: the velocity vector in the bladeless region is neatly distributed in a circle, and the high-speed vector is reduced; the high vorticity region between the blades is completely eliminated, and the medium vorticity range is reduced by about 30% compared with the single top cover water supply.

[0067] Reference Figure 5 As shown, the turbine blade passage vortex is completely eliminated on the suction side inlet side, and the scale of the lower side vortex structure on the outlet side is reduced by about 50% compared to the single top cover water supply.

[0068] Reference Figure 6 As shown, the circulation of the runner exit velocity is reduced by about 70% in the central low circulation region, and the high circulation region on the wall is reduced from 580 to 500, with a more gradual radial distribution.

[0069] Reference Figure 7As shown, the tailrace vortex zone is broken into small-scale vortices, and the pressure gradient at each section is significantly reduced.

[0070] Reference Figure 8 As shown, the pressure pulsation amplitude is as follows: at the GV6 monitoring point near the impeller, the main frequency pulsation amplitude at 28.956 Hz is 0.0458 when no water is added, 0.0095 when water is added to the single top cover, and remains at 0.00105 when water is added in a coordinated manner.

[0071] At the RU7 monitoring point located at the inlet of the turbine, the amplitude of the main frequency pulsation at 0.499 Hz was 0.0084 when no water was added, 0.0031 when water was added by a single top cover, and further decreased to 0.0025 when water was added in a coordinated manner.

[0072] At the RU9 monitoring point located at the inlet of the turbine, the amplitude of the main frequency pulsation at 1.497 Hz was 0.0141 when no water was added, 0.0045 when water was added by a single top cover, and further decreased to 0.0030 when water was added in a coordinated manner.

[0073] At the TU1 monitoring point near the wall of the tailrace pipe inlet section, the amplitude of the main frequency pulsation at 0.499 Hz was 0.0162 when no water was added, 0.0070 when water was added through the single spindle center hole, and remained at 0.0068 when water was added in a coordinated manner.

[0074] At the TU2 monitoring point at the center of the tailrace pipe inlet section, the amplitude of the main frequency pulsation at 0.499 Hz is 0.0145 when no water is added, 0.0101 when water is added to the single main shaft center hole, and 0.0040 when water is added in a coordinated manner.

[0075] At the TU4 monitoring point near the wall of the straight conical section of the tailrace pipe, the amplitude of the main frequency pulsation at 0.499 Hz was 0.0309 when no water was added, 0.0184 when water was added through the single spindle center hole, and further decreased to 0.0153 when water was added in a coordinated manner.

[0076] At the TU5 monitoring point at the center of the straight conical section of the tailpipe, the amplitude of the main frequency pulsation at 0.499 Hz increased to a certain extent due to the influence of the high-speed jet from the water injection pipe. It was 0.0125 when no water was added, 0.0237 when water was added to the single main shaft center hole, and further decreased to 0.0205 when water was added in a coordinated manner. In comparison, the increase was smaller when water was added in a coordinated manner.

[0077] The above results show that the method of the present invention can significantly suppress wideband pressure pulsation under partial load conditions of mixed-flow target turbines and improve the operational stability of the unit.

[0078] For example, when the target turbine is a mixed-flow turbine, its rated flow rate Qn = 54 m³ / s. 3When the load condition is 0.60Qn, the method of this invention is implemented as follows: the water replenishment amount of the top cover is 0.02Qn, and the water replenishment amount of the spindle center hole is 0.03Qn.

[0079] In the bladeless and impeller zones, the amplitude of the main frequency pressure pulsation during coordinated water replenishment decreased by approximately 16% compared to single top cover water replenishment. This also resulted in an 8% reduction in the amplitude of the pressure pulsation on the wall of the tailrace bend compared to single main shaft center hole water replenishment. Despite significantly optimizing the pressure pulsation at the measuring points of each component, the coordinated water replenishment scheme resulted in a mere 1.1% decrease in unit efficiency.

[0080] The examples described in this invention are not limited to the specific embodiments listed above. The examples are merely illustrative to facilitate understanding of the invention and do not constitute a limitation on the scope of protection of this invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of this invention should be included within the scope of protection.

[0081] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in this specification, they should all fall within the protection scope of the present invention.

Claims

1. A method for suppressing pressure pulsation of a hydraulic turbine based on synergistic jet replenishment, characterized in that, Includes the following steps: Step 1: Modify the target turbine by adding a top cover water supply channel and a main shaft center hole water supply channel; Step 2: Determine the operating characteristic parameters of the target turbine and the corresponding acquisition devices, and then conduct operating condition tests on the target turbine to analyze and obtain the target load operating condition range of the target turbine. Step 3: Conduct coordinated water replenishment tests on the target turbine based on the target load operating range, and then analyze and obtain the optimal combination of coordinated water replenishment parameters for the target turbine within the target load operating range; Step 4: Based on the target load conditions and the optimal combination of coordinated water replenishment parameters, replenish water to the target turbine.

2. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 1, characterized in that, The modification of the target turbine, including the addition of a top cover water supply channel and a main shaft center hole water supply channel, is described in the following process: ST21. Several water injection holes are evenly distributed along the circumference of the top cover of the target turbine, wherein the axis of each water injection hole is perpendicular to the water inlet side of the turbine blade, thereby forming a water replenishment channel for the top cover. ST22. Use the original main shaft center hole of the target turbine as the main shaft center hole water supply channel, and set the outlet of the main shaft center hole water supply channel at the center of the tailrace pipe inlet at the lower end of the main shaft. At the same time, install a flow stabilizer or flow equalization hood at the outlet to form the main shaft center hole water supply channel. ST23. Finally, install a top cover water supply device and connect it to the top cover water supply channel. Install a spindle center hole water supply device and connect it to the spindle center hole water supply channel. Then, connect the top cover water supply device and the spindle center hole water supply device to the coordinated control unit for electrical control.

3. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 2, characterized in that, The operating condition characteristic parameters include pressure pulsation data at each preset position of the target turbine, frame vibration amplitude and vibration frequency, swing value and swing fluctuation of each bearing position of the main shaft, radial distribution data of velocity circulation at the runner outlet section, flow rate and active power output; the acquisition devices include a power plant computer monitoring system, pressure pulsation sensor, vibration sensor, main shaft swing sensor, flow acquisition device and power output acquisition device.

4. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 3, characterized in that, The specific process for conducting the operating condition test on the target turbine is as follows: ST41. Maintain the target turbine's clean water head at the unit's design operating head, and deploy various data acquisition devices to unify the data acquisition timeline of each device. ST42. Obtain the rated flow rate of the target turbine from the technical manual, and then set various uniform gradient load conditions based on the rated flow rate. For any load condition, after the target turbine has been running under the load condition for a preset time, collect the operating condition characteristic parameters of the target turbine through various acquisition devices. ST43. Following the steps in ST42, conduct operating condition tests on the target turbine under various load conditions.

5. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 4, characterized in that, The analysis yields the target load operating range for the target turbine, and the specific process is as follows: ST51. Extract the pressure pulsation data at each preset position of the target turbine under each load condition from the operating condition characteristic parameters obtained from ST41-ST43 tests. Perform Fourier transform on the pressure pulsation data to obtain the full-band pulsation amplitude and pulsation main frequency at each position of the target turbine under each load condition. ST52. Obtain the unit operating frequency of the target turbine from the technical manual. When the pulsating main frequency is ≤0.6 times the unit operating frequency, it is defined as low-frequency pulsation. When the main frequency is ≥10 times the unit operating frequency, it is defined as high-frequency pulsation. Then, extract the peak amplitude of low-frequency pulsation and peak amplitude of high-frequency pulsation and normalize them. Record the load condition intervals corresponding to the normalized low-frequency pulsation amplitude ≥0.0014 and high-frequency pulsation amplitude ≥0.0095 as the primary target load condition intervals. ST53. Extract the radial distribution data of velocity circulation at the runner outlet section from the characteristic parameters of the operating conditions obtained from the ST41-ST43 tests, calculate the coefficient of variation of velocity circulation at the runner outlet section, and then record each load condition corresponding to the coefficient of variation > 0.35 as the target load condition. ST54. From the operating condition characteristic parameters obtained from ST41-ST43 tests, extract the bearing spindle runout amplitude and top cover vibration amplitude of the target turbine under each load condition. Then, find the total bearing clearance of the target turbine from the technical manual. Finally, record the corresponding load condition intervals when the bearing spindle runout amplitude is ≥0.7 times the total bearing clearance or the top cover vibration amplitude is >90um as the primary target load condition intervals. ST55. Integrate the primary target load condition intervals in ST52 and ST54 to obtain the target load condition interval.

6. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 5, characterized in that, The target load operating range is 60%-80% of the target turbine's rated flow.

7. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 6, characterized in that, The specific process of conducting coordinated water replenishment tests on the target turbine based on the target load operating range is as follows: ST71. Maintain the target turbine's clean water head at the unit's design operating head, and deploy various data acquisition devices to unify the data acquisition timeline of each device. ST72. Set up each uniform gradient test condition based on the target load condition range, and obtain each combination of coordinated water replenishment parameters according to the preset gradient cross setting. The combination of water replenishment parameters includes the top cover water replenishment flow rate and the main shaft center hole water replenishment flow rate. ST73. For any test condition, the target turbine is sequentially replenished with water using various combinations of coordinated water replenishment parameters. After the target turbine has been running for a preset time, the operating condition characteristic parameters of the target turbine are collected by various acquisition devices. Based on this, the corresponding operating condition characteristic parameters of the target turbine after replenishing water with various combinations of coordinated water replenishment parameters under the test condition are obtained. ST74 and ST73 are repeated. For each test condition, the coordinated water replenishment parameter combination is used to conduct the coordinated water replenishment test. Based on this test, the corresponding operating condition characteristic parameters of each coordinated water replenishment parameter combination after water replenishment to the target turbine under each test condition are obtained.

8. The method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 7, characterized in that, The analysis yielded the optimal combination of coordinated water supply parameters for the target turbine within the target load operating range. The specific process is as follows: Normalize the characteristic parameters of the target turbine after water replenishment by the combination of coordinated water replenishment parameters under each test condition obtained from ST71-ST74 tests. The normalized operating condition characteristic parameters are weighted and summed to obtain the operating condition stability coefficient. Based on this, the operating condition stability coefficient of the target turbine corresponding to each combination of coordinated water supply parameters under each test condition is calculated, denoted as . Where i and j represent the test condition number and the combined water replenishment parameter number, respectively, and both i and j are positive integers. Then, according to the calculation formula: The comprehensive operating condition stability coefficient corresponding to the target load operating condition range for each combination of coordinated water replenishment parameters is calculated, where I is the total number of test operating conditions. The combination of coordinated water replenishment parameters corresponding to the minimum comprehensive operating condition stability coefficient is denoted as the optimal combination of coordinated water replenishment parameters.

9. A method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 8, characterized in that, The optimal combination of coordinated water supply parameters is as follows: the water supply flow rate of the top cover is 2% of the rated flow rate of the target turbine, and the water supply flow rate of the main shaft center hole is 3% of the rated flow rate of the target turbine.

10. A method for suppressing turbine pressure pulsation based on synergistic jet water supply according to claim 9, characterized in that, The process of replenishing water to the target turbine based on the target load condition and optimal coordinated jet water replenishment parameters is as follows: During the operation of the target turbine, the real-time load condition of the target turbine is monitored, and the real-time load condition of the target turbine is compared with the target load condition range. When the real-time load condition of the target turbine reaches the target load condition range, the top cover water supply device and the main shaft center hole water supply device are activated simultaneously through the coordinated control unit. The top cover water supply device supplies water to the target turbine at 2% of the rated flow rate of the target turbine through the top cover water supply channel, and the main shaft center hole water supply device supplies water to the target turbine at 3% of the rated flow rate of the target turbine through the main shaft center hole water supply channel, thus simultaneously supplying water to the target turbine.

Images