Active suppression system and method for coupled vibration of one-hole multi-tail water system

Abstract

The invention discloses an active suppression system and method for coupling vibration of a one-hole multi-tail water system, and the system comprises an active elastic regulation and control device which is installed in a runner cone cavity of a runner of a water turbine of each unit, and the active elastic regulation and control device comprises a central air supplement pipe and a rubber sleeve which sleeves the tail part of the central air supplement pipe; the rubber sleeve is fixedly connected and sealed with the tail of the central blowdown pipe to form an independent variable-volume gas cavity, namely a rubber cavity, an electromagnetic air valve is arranged at the tail of the central blowdown pipe, and a pressure sensor is arranged at an outlet of a unit in the tail water system. The pressure sensor and the electromagnetic air valve are respectively connected with the controller through control signal lines, and the air charging and discharging system is communicated with the head of the central air supplementing pipe; the elastic regulation and control device is arranged in the cavity of the runner runner cone of the water turbine, the water hammer wave propagation characteristic of a tail water system is actively changed, and suppression of coupling vibration is achieved.

Description

Technical Field

[0001] This invention relates to the field of vibration suppression technology for hydropower units, and in particular to an active suppression system and method for coupled vibration of a multi-unit tailrace system in a single tunnel. Background Technology

[0002] To save on investment in water conveyance systems and improve water energy utilization efficiency, large hydropower stations and pumped storage power stations often adopt a "one tunnel, two units" or "one tunnel, multiple units" layout. However, in this layout, the tailrace systems are interconnected, and the hydraulic interference between units can easily cause water hammer wave coupling oscillations in the tailrace system, which in turn can lead to abnormal vibration problems in the units.

[0003] When some units are operating and others are shut down, the tailrace pressure wave (i.e., water hammer wave) caused by the operating units will be transmitted to the tailrace pipe of the shut-down units through the branch pipe. The water hammer wave propagates alternately between the two units, causing water hammer wave oscillations. The water hammer wave acts on the unit structure, causing significant vibration responses in locations such as the runner and top cover. Actual measurements show that the vibration amplitude of the top cover of the shut-down unit may even approach or exceed the level during operation, seriously affecting the safe and stable operation of the unit. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide an active suppression system and method for coupled vibration of a multi-turbine tailrace system. By setting an elastic control device in the cavity of the turbine runner discharge cone, the water hammer wave propagation characteristics of the tailrace system are actively changed, thereby suppressing coupled vibration.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an active suppression system for coupled vibration of a multi-unit tailrace system, including an active elastic control device installed in the discharge cone cavity of the turbine runner of each unit. The active elastic control device includes a central air supply pipe and a rubber sleeve fitted at its tail. The rubber sleeve is fixedly connected to and sealed with the tail of the central air supply pipe to form an independent variable volume gas cavity, i.e., a rubber cavity. An electromagnetic air valve is provided at the tail of the central air supply pipe. A pressure sensor is provided at the unit outlet position in the tailrace system. The pressure sensor and the electromagnetic air valve are respectively connected to the controller through control signal lines. The air supply system is connected to the head of the central air supply pipe.

[0006] Preferably, the central air supply pipe is arranged along the central vent hole of the turbine main shaft, and several small holes communicating with the gas cavity are evenly opened on the outer wall of the tail end of the central air supply pipe, and the electromagnetic air valve is installed at each of the small holes.

[0007] Preferably, the rubber sleeve is a spherical structure made of highly elastic water-resistant rubber with an elastic modulus of 2 to 4 MPa, which can achieve controllable elastic deformation within a pressure range of 0.1 to 1.5 MPa. The thickness of the rubber sleeve is determined according to the design pressure of the tailwater system.

[0008] Preferably, the response time of the electromagnetic air valve is ≤0.1s, which is used to meet the rapid response requirements of water hammer wave period adjustment.

[0009] Preferably, the air supply system includes an air tank and an air pump; the air outlet of the air tank is connected to one end of the air supply pipe, the other end of the air supply pipe is connected to the central air supply pipe, and the solenoid valve on the air supply pipe is connected to the controller; the air pump's suction port is connected to one end of the suction pipe, the other end of the suction pipe is connected to the central air supply pipe, and the solenoid valve on the suction pipe is connected to the controller.

[0010] In addition, the present invention also discloses an active suppression method for coupled vibration of a multi-machine tailrace system in a single tunnel, characterized by comprising the following steps: Step 1: Real-time acquisition of transient pressure signals at the unit outlet location in the tailrace system using pressure sensors; Step 2: The controller processes the collected pressure signal to identify the pressure peaks and valleys and the propagation phase caused by the water hammer wave; Step 3: The controller controls the opening of the electromagnetic air valve to inflate the rubber cavity during the pressure trough stage and controls the opening of the electromagnetic air valve to expel part of the gas in the rubber cavity during the pressure peak stage, based on the phase of the pressure change. Step 4: By dynamically adjusting the gas pressure and volume inside the rubber cavity, the local equivalent elastic modulus of the tailwater system is changed, forming a reverse compensation wave to weaken the pressure fluctuation energy and achieve unit vibration suppression.

[0011] Furthermore, in step 1, the sampling frequency of the pressure sensor is not less than 500Hz, and the sampling locations include key parts of the unit outlet and tailwater pipe to ensure comprehensive capture of pressure fluctuation signals of the tailwater system.

[0012] Furthermore, in step 2, the controller's processing of the pressure signal includes: performing a fast Fourier transform on the pressure signal collected by the pressure sensor, extracting the main fluctuation frequency and its phase information, combining historical signals and flow conditions, and using an adaptive filtering algorithm to predict the peak and trough times of the next cycle.

[0013] Furthermore, in step 3, the controller bases its decisions on the real-time measured pressure pulsation amplitude. A h ( t ), through formula A eff = A h ( t ) (1- βQ g / Q maxDynamically adjust the gas filling and emptying rate per unit time Q g ,in Q max This represents the system's maximum charge and discharge capacity. β To adjust the sensitivity coefficient, the value range is 0.3 to 0.7; A eff This represents the effective pressure pulsation amplitude after air chamber adjustment.

[0014] Furthermore, in step 3, when the electromagnetic air valve is opened to inflate the rubber cavity during the pressure trough stage, the electromagnetic valve on the air supply pipe is also opened simultaneously, and the electromagnetic valve on the extraction pipe is closed. The compression control in the air tank enters the central air supply pipe through the air supply pipe, thereby inflating the rubber cavity.

[0015] Furthermore, in step 3, when the electromagnetic air valve is opened to discharge some of the gas inside the rubber cavity during the peak pressure stage, the electromagnetic valve on the suction pipe is also opened simultaneously, and the electromagnetic valve on the air supply pipe is closed. The suction pump then pumps air from the central air supply pipe through the suction pipe, thereby discharging some of the gas inside the rubber cavity.

[0016] Furthermore, in step 4, the gas inside the rubber cavity satisfies the multivariate process equation. p g V g n = constant, in the formula p g The pressure of the gas inside the air chamber. V g The volume of the rubber cavity. n For multi-factor index, air quality is taken as 1.2 to 1.4; By using an electromagnetic air valve to charge and vent air, the pressure and volume of the air chamber are changed, thus increasing the equivalent instantaneous pressure Δ of the tailwater system. p eff (t)=Δ p h ( t )-Δ p g ( t ), where Δ p h ( t ) represents the original water hammer wave pressure, Δ p g ( t This is to regulate the pressure of the air chamber, ultimately achieving active compensation for pressure fluctuations.

[0017] Beneficial effects of this invention: 1. This invention suppresses coupled vibrations by actively altering the propagation characteristics of water hammer waves in the tailrace system through an elastic control device installed in the turbine runner's spillway cone cavity. Specifically, when the tailrace pressure wave generated by the operating unit is transmitted to the shutdown unit location via the tailrace pipe, the active elastic control device responds according to real-time monitoring signals: during the pressure wave peak, the cavity exhausts air to absorb energy and reduce local pressure; during the pressure wave trough, the cavity fills with air to release energy and compensate for local low pressure; thus, a "reverse compensation wave" with opposite phase is formed at the unit outlet, effectively weakening the pressure fluctuation energy and achieving vibration suppression.

[0018] 2. This invention features active control characteristics: Unlike traditional passive energy dissipation devices (such as energy dissipation pools and tailrace diffuser optimization), this solution can respond to transient fluctuations in the tailrace system in real time, achieving adaptive adjustment. The system elasticity of this invention is adjustable: Through gas filling and discharging, the equivalent bulk elastic modulus of the tailrace can be dynamically changed, enabling periodic tuning of the system's water hammer wave transmission characteristics. This invention effectively reduces vibration: Simulation and experimental results show that this device can reduce the vibration amplitude of the shut-down unit by more than 40%, and reduce the peak-to-peak value of tailrace pressure pulsation by about 30%. This invention has a simple structure and is easy to integrate: The device is installed inside the spillway cone, without affecting the original unit's hydraulic structure, and can be added to or retrofitted into existing power plant units. Attached Figure Description

[0019] Figure 1 A schematic diagram of an active system for suppressing coupled vibrations in a multi-machine tailrace system with a single tunnel. Figure 2 This is a schematic diagram of the active elastic control device in this invention; Figure 3 This is a schematic diagram showing the connection between the air supply tube and the rubber cavity in this invention; Figure 4 This is a schematic diagram of the active control principle of gas filling and discharging control according to the present invention.

[0020] In the diagram, 1-Unit 1; 2-Unit 2; 3-Common tailrace pipe; 4-Turbine runner; 5-Drain cone cavity; 6-Active elastic control device; 7-Central air supply pipe; 8-Rubber sleeve; 9-Rubber cavity; 10-Solenoid air valve; 11-Pressure sensor; 12-Controller; 13-Air supply pipe; 14-Air storage tank; 15-Control signal line; 16-Tailrace flow direction; 17-Schematic diagram of pressure wave propagation path between units; 18-Air extraction pump; 19-Air extraction pipe. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: As Figures 1 to 4As shown, an active suppression system for coupled vibration of a multi-unit tailrace system includes an active elastic control device 6 installed in the cavities 5 of the spillway cones of each turbine runner 4. The active elastic control device 6 includes a central air supply pipe 7 and a rubber sleeve 8 fitted at its tail. The rubber sleeve 8 is fixedly connected to and sealed with the tail of the central air supply pipe 7 to form an independent variable-volume gas cavity, i.e., a rubber cavity 9. An electromagnetic air valve 10 is provided at the tail of the central air supply pipe 7. A pressure sensor 11 is provided at the turbine outlet of the tailrace system. The pressure sensor 11 and the electromagnetic air valve 10 are respectively connected to the controller 12 through control signal lines 15. The air supply and exhaust system is connected to the head of the central air supply pipe 7.

[0023] Preferably, the central air supply pipe 7 is arranged along the central vent hole of the turbine main shaft, and several small holes communicating with the gas cavity are evenly opened on the outer wall of the tail end of the central air supply pipe 7, and the electromagnetic air valve 10 is installed at each of the small holes.

[0024] Preferably, the rubber sleeve 8 is a spherical structure made of highly elastic water-resistant rubber with an elastic modulus of 2 to 4 MPa, which can achieve controllable elastic deformation within a pressure range of 0.1 to 1.5 MPa. The thickness of the rubber sleeve 8 is determined according to the design pressure of the tailwater system.

[0025] Preferably, the response time of the electromagnetic air valve 10 is ≤0.1s, which is used to meet the rapid response requirements of water hammer wave period adjustment.

[0026] Preferably, the air supply system includes an air tank 14 and an air pump 18; the air outlet of the air tank 14 is connected to one end of the air supply pipe 13, the other end of the air supply pipe 13 is connected to the central air supply pipe 7, and the solenoid valve on the air supply pipe 13 is connected to the controller 12; the air intake of the air pump 18 is connected to one end of the air extraction pipe 19, the other end of the air extraction pipe 19 is connected to the central air supply pipe 7, and the solenoid valve on the air extraction pipe 19 is connected to the controller 12.

[0027] In the above technical solution, 1-Unit 1 (operating unit, generating tailwater pressure waves); 2-Unit 2 (shutdown unit, vibrating due to tailwater coupling); 3-Common tailwater pipeline (one tunnel shared by multiple units for the tailwater system); 4-Turbine runner (core component of the turbine, including the spillway cone); 5-Spillway cone cavity (space area for installing the active control device); 6-Active elastic control device (core component of this invention); 7-Central air supply pipe (central axial pipeline of the device, used for filling and discharging gas); 8-Rubber sleeve (elastic body sleeved on the outside of the air supply pipe, forming a sealed air cavity); 9-Rubber cavity body (composed of the air supply pipe). 10- Variable volume space formed by the rubber sleeve; 11- Electromagnetic air valve (a controllable valve for controlling gas filling and discharge); 12- Pressure sensor (real-time detection of tailwater pressure fluctuation signals); 13- Controller (the core unit that processes pressure signals and generates control commands); 14- Air supply pipe (a pipeline connecting an external air source and a make-up air pipe); 15- Air storage tank (an energy storage unit that provides compressed air); 16- Control signal line (connecting the controller to the solenoid valve and sensor); 17- Tailwater flow direction (an arrow indicating the main direction of water flow in the tailwater pipe); 18- Schematic diagram of the propagation path of pressure waves between units.

[0028] like Figure 1 As shown, when operating unit 1 is generating electricity, its tailwater flows through the common tailwater pipe 3, generating periodic pressure waves. These pressure waves propagate and reflect within the pipe, transmitting to the tailwater chamber of the shut-down unit 2, causing vibration in the shut-down unit. This invention addresses this by introducing controllable elastic units (active elastic control devices 6) into the drain cone cavities 5 of both units 1 and 2, achieving real-time compensation and reduction of the pressure waves from both units.

[0029] Its working principle is as follows: Figure 3As shown, during system operation, the controller 12 continuously receives signals from the pressure sensor 11 and calculates the instantaneous phase and amplitude of the tailwater pressure wave. When the water hammer wave is detected to be in the pressure trough stage (i.e., the tailwater low-pressure zone), the controller opens the solenoid air valve 10 to inflate the rubber cavity 9, and simultaneously opens the solenoid valve on the air supply pipe 13 and closes the solenoid valve on the extraction pipe 19. The compression control in the air storage tank 14 enters the central air supply pipe 7 through the air supply pipe 13, thereby inflating the rubber cavity 9 and increasing the local pressure. When the pressure peak stage (i.e., the tailwater high-pressure zone) is detected, the controller opens the solenoid air valve 10 to discharge some gas from the rubber cavity 9, and simultaneously opens the solenoid valve on the extraction pipe 19 and closes the solenoid valve on the air supply pipe 13. The extraction pump 18 performs an extraction process on the central air supply pipe 7 through the extraction pipe 19, thereby discharging some gas from the rubber cavity 9. The cavity deflates and contracts, absorbing some energy. Through periodic inflation and deflation, the bulk elastic modulus of the cavity dynamically changes with pressure fluctuations, thereby causing anti-phase interference in the local pressure response of the tailrace. This reverse compensation effect can significantly weaken the propagation and reflection of water hammer waves in the system, achieving decoupling and suppression of vibration energy between units.

[0030] Example 2: The present invention also discloses an active suppression method for coupled vibration of a multi-machine tailrace system in a single tunnel, characterized by comprising the following steps: Step 1: Real-time acquisition of transient pressure signals at the unit outlet position in the tailrace system using pressure sensor 11; Step 2: The controller 12 processes the collected pressure signal to identify the pressure peak and valley changes and propagation phase caused by the water hammer wave; Step 3: According to the pressure change phase, the controller 12 controls the electromagnetic air valve 10 to open and inflate the rubber cavity 9 during the pressure trough stage, and controls the electromagnetic air valve 10 to open and discharge some of the gas inside the rubber cavity 9 during the pressure peak stage. Step 4: By dynamically adjusting the gas pressure and volume inside the rubber cavity 9, the local equivalent elastic modulus of the tailwater system is changed, forming a reverse compensation wave to weaken the pressure fluctuation energy and achieve unit vibration suppression.

[0031] Furthermore, in step 1, the sampling frequency of pressure sensor 11 is not less than 500Hz, and the sampling locations include key parts of the unit outlet and tailwater pipe to ensure comprehensive capture of pressure fluctuation signals of the tailwater system.

[0032] Furthermore, in step 2, the process of the controller 12 processing the pressure signal includes: performing a fast Fourier transform on the pressure signal collected by the pressure sensor 11, extracting the main fluctuation frequency and its phase information, combining historical signals and flow conditions, and using an adaptive filtering algorithm to predict the peak and trough times of the next cycle.

[0033] Furthermore, in step 3, the controller 12 determines the pressure pulsation amplitude based on the real-time measured value. A h ( t ), through formula A eff = A h ( t (1-) βQ g / Q max Dynamically adjust the gas filling and emptying rate per unit time Q g ,in Q max This represents the system's maximum charge and discharge capacity. β To adjust the sensitivity coefficient, the value range is 0.3 to 0.7; A eff This represents the effective pressure pulsation amplitude after air chamber adjustment.

[0034] In this embodiment, the controller is based on the pressure pulsation amplitude measured in real time. A h ( t ), through formula A eff = A h ( t (1-) βQ g / Q max Dynamic adjustment Qg This allows for active regulation of the air chamber pressure, stabilizing pressure changes in the tailwater system. The specific principle and formula relationships are explained below: In the active suppression system described in this invention, the coupled vibration of the tailrace system is mainly caused by the periodic transmission of water hammer waves, and its instantaneous pressure change can be expressed as: p ( t )= p 0+Δ p ( t ); in, p 0 represents steady-state pressure, Δ p ( t ) represents the instantaneous pressure pulsation generated by the water hammer wave.

[0035] To mitigate periodic pressure fluctuations within the tailrace system, this invention incorporates an adjustable air chamber within the unit's discharge cone. This chamber alters the equivalent elastic properties of the local boundary through inflation and deflation. The gas within the air chamber satisfies a multivariate process equation: p gV g n = constant; In the formula p g V is the gas pressure inside the gas chamber. g Let be the volume of the air cavity, and n be the polynomial exponent (1.2–1.4 for air). Linearizing for small perturbations, we obtain: Δ p g / p g0 =- n Δ V g / V g0； If the change in air chamber volume is due to the filling and discharging volume Q g ( t If the decision is made, then: d V g / d t = Q g ( t ); After substituting the values, we obtain the relationship between the rate of change of pressure within the air chamber and the volume of air supplied: d(Δpg) / dt=- np g0 Q g ( t ) / V g0 (1); Equation (1) shows that when the gas is filled in ( Q g When the pressure is >0, the pressure inside the air chamber rises, creating a reverse pressure; during exhaust ( Q g When the pressure in the air cavity decreases (<0), it absorbs some of the pressure wave energy.

[0036] When the air chamber is coupled with the tailrace system, the equivalent instantaneous pressure of the tailrace system can be expressed as: Δ p eff (t)=Δ p h ( t )-Δ p g ( t (2); Where, Δ p h ( t The original water hammer wave pressure is 0. Δ pg ( t () is used to regulate the pressure of the air chamber.

[0037] Steady-state analysis of the tailrace system's dominant frequency response yielded the attenuation relationship of the pressure pulsation amplitude: A eff / A h =1 / sqrt(1+( np g0 ω / kV g0 ) 2 (3); In the formula: A h This represents the original water hammer wave pressure pulsation amplitude. A eff This represents the effective pressure pulsation amplitude after air chamber adjustment. ω The dominant frequency angular velocity of the water hammer wave; k It is a coupling constant related to the bulk modulus of the tailrace system and the characteristics of the pipeline.

[0038] As can be seen from equation (3), increasing the volume of the gas or increasing the initial pressure of the gas chamber can effectively improve the equivalent elasticity of the system, reduce the pressure pulsation amplitude, and achieve active suppression of coupled vibration.

[0039] In the implementation of the control algorithm, linearized empirical relationships can be used: A eff = A h (1- βQ g / Q max (4); in: Q g : Current gas charge / discharge rate per unit time; Q max : The system's maximum charging and discharging capacity; β Adjust the sensitivity coefficient to 0.3 to 0.7.

[0040] The controller is based on the real-time measured pressure pulsation amplitude. A h ( t ), dynamically adjusted through formula (4) Qg This enables active regulation of the air chamber pressure, making the pressure changes in the tailwater system more stable.

[0041] The above model can realize a quantitative mapping relationship between the inflation / exhaust volume and the tailwater pressure pulsation amplitude, providing a theoretical basis for the active control algorithm of this invention.

[0042] Furthermore, in step 3, when the electromagnetic air valve 10 is opened to inflate the rubber cavity 9 during the pressure trough stage, the electromagnetic valve on the air supply pipe 13 is also opened simultaneously, and the electromagnetic valve on the suction pipe 19 is closed. The compression control in the air tank 14 enters the central air supply pipe 7 through the air supply pipe 13, thereby inflating the rubber cavity 9.

[0043] Furthermore, in step 3, when the electromagnetic air valve 10 is opened to discharge some of the gas inside the rubber cavity 9 during the peak pressure stage, the electromagnetic valve on the suction pipe 19 is also opened simultaneously, and the electromagnetic valve on the air supply pipe 13 is closed. The suction pump 18 performs a suction process on the central air supply pipe 7 through the suction pipe 19, thereby discharging some of the gas inside the rubber cavity 9.

[0044] Furthermore, in step 4, the gas inside the rubber cavity 9 satisfies the polyhedral process equation. p g V g n = constant, in the formula p g The pressure of the gas inside the air chamber. V g The volume of the rubber cavity is 9. n For multi-factor index, air quality is taken as 1.2 to 1.4; By using electromagnetic air valve 10 to charge and vent air, the pressure and volume of the air chamber are changed, thus increasing the equivalent instantaneous pressure Δ of the tailwater system. p eff (t)=Δ p h ( t )-Δ p g ( t ), where Δ p h ( t ) represents the original water hammer wave pressure, Δ p g ( t This is to regulate the pressure of the air chamber, ultimately achieving active compensation for pressure fluctuations.

[0045] It should be noted that the present invention can be applied to the arrangement of hydropower station units with a shared tailrace pipeline, including but not limited to the type of one tunnel with two, three or more units; it is also applicable to the active control of tailrace pressure pulsation in pumped storage power stations.

[0046] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. An active vibration suppression system for a multi-machine tailrace system in a single tunnel, characterized in that: The active elastic control device (6) is installed in the cavitation cone cavity (5) of the turbine runner (4) of each unit. The active elastic control device (6) includes a central air supply pipe (7) and a rubber sleeve (8) fitted at its tail. The rubber sleeve (8) is fixedly connected to the tail of the central air supply pipe (7) and sealed to form an independent variable volume gas cavity, namely the rubber cavity (9). The tail of the central air supply pipe (7) is provided with an electromagnetic air valve (10). A pressure sensor (11) is provided at the unit outlet position in the tailwater system. The pressure sensor (11) and the electromagnetic air valve (10) are respectively connected to the controller (12) through the control signal line (15). The air supply system is connected to the head of the central air supply pipe (7).

2. The active suppression system for coupled vibration of a multi-machine tailrace system in a single tunnel according to claim 1, characterized in that: The central air supply pipe (7) is arranged along the central air vent of the turbine main shaft. Several small holes communicating with the gas cavity are evenly opened on the outer wall of the tail of the central air supply pipe (7). The electromagnetic air valve (10) is installed at each small hole.

3. The active suppression system for coupled vibration of a multi-machine tailrace system in a single tunnel according to claim 1, characterized in that: The rubber sleeve (8) is a spherical structure made of highly elastic water-resistant rubber with an elastic modulus of 2 to 4 MPa. It can achieve controllable elastic deformation within a pressure range of 0.1 to 1.5 MPa. The thickness of the rubber sleeve (8) is determined according to the design pressure of the tailwater system.

4. The active suppression system for coupled vibration of a multi-machine tailrace system in a single tunnel according to claim 1, characterized in that: The electromagnetic air valve (10) has a response time of ≤0.1s, which is used to meet the rapid response requirements of water hammer wave period regulation.

5. The active suppression system for coupled vibration of a multi-machine tailrace system in a single tunnel according to claim 1, characterized in that: The air supply system includes an air tank (14) and an air pump (18); the air outlet of the air tank (14) is connected to one end of the air supply pipe (13), the other end of the air supply pipe (13) is connected to the central air supply pipe (7), and the solenoid valve on the air supply pipe (13) is connected to the controller (12); the air outlet of the air pump (18) is connected to one end of the air extraction pipe (19), the other end of the air extraction pipe (19) is connected to the central air supply pipe (7), and the solenoid valve on the air extraction pipe (19) is connected to the controller (12).

6. An active suppression method for an active suppression system based on the coupled vibration of a single-tunnel multi-machine tailrace system as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Real-time acquisition of transient pressure signals at the unit outlet position in the tailrace system using pressure sensor (11); Step 2: The controller (12) processes the collected pressure signal to identify the pressure peak and valley changes and propagation phase caused by the water hammer wave; Step 3: The controller (12) controls the electromagnetic air valve (10) to open and inflate the rubber cavity (9) according to the pressure change phase. During the pressure trough stage, the controller controls the electromagnetic air valve (10) to open and discharge some of the gas inside the rubber cavity (9). Step 4: By dynamically adjusting the gas pressure and volume inside the rubber cavity (9), the local equivalent elastic modulus of the tailwater system is changed, and a reverse compensation wave is formed to weaken the pressure fluctuation energy, thereby achieving unit vibration suppression.

7. The active suppression method for the coupled vibration suppression system of a multi-machine tailrace system in a single tunnel as described in claim 6, characterized in that: In step 1, the sampling frequency of the pressure sensor (11) is not less than 500Hz, and the sampling locations include the unit outlet and key parts of the tailwater pipe to ensure that the pressure fluctuation signal of the tailwater system is fully captured.

8. The active suppression method for the coupled vibration suppression system of a multi-machine tailrace system in a single tunnel as described in claim 6, characterized in that: In step 2, the process of the controller (12) processing the pressure signal includes: performing a fast Fourier transform on the pressure signal collected by the pressure sensor (11), extracting the main fluctuation frequency and its phase information, combining historical signals and flow conditions, and using an adaptive filtering algorithm to predict the peak and trough times of the next cycle.

9. The active suppression method for the coupled vibration suppression system of a multi-machine tailrace system in a single tunnel according to claim 6, characterized in that: In step 3, the controller (12) determines the pressure pulsation amplitude based on the real-time measured value. A h ( t ), through formula A eff = A h ( t ) (1- βQ g / Q max Dynamically adjust the gas filling and emptying rate per unit time Q g ,in Q max This represents the system's maximum charge and discharge capacity. β To adjust the sensitivity coefficient, the value range is 0.3 to 0.7; A eff This represents the effective pressure pulsation amplitude after air chamber adjustment.

10. The active suppression method for the coupled vibration suppression system of a multi-machine tailrace system in a single tunnel according to claim 6, characterized in that: In step 3, when the electromagnetic air valve (10) is opened to inflate the rubber cavity (9) during the pressure trough stage, the electromagnetic valve on the air supply pipe (13) is also opened and the electromagnetic valve on the suction pipe (19) is closed. The compression control in the air tank (14) enters the central air supply pipe (7) through the air supply pipe (13), thereby inflating the rubber cavity (9).

11. The active suppression method for the coupled vibration suppression system of a multi-machine tailrace system in a single tunnel as described in claim 6 or 10, characterized in that: In step 3, when the electromagnetic air valve (10) is opened to discharge some of the gas inside the rubber cavity (9) during the peak pressure stage, the electromagnetic valve on the suction pipe (19) is also opened simultaneously, and the electromagnetic valve on the air supply pipe (13) is closed. The suction pump (18) performs the suction process on the central air supply pipe (7) through the suction pipe (19), thereby discharging some of the gas inside the rubber cavity (9).

12. The active suppression method for the coupled vibration suppression system of a multi-machine tailrace system in a single tunnel as described in claim 6, characterized in that: In step 4, the gas inside the rubber cavity (9) satisfies the polyhedral process equation. p g V g n = constant, in the formula p g The pressure of the gas inside the air chamber. V g The volume of the rubber cavity (9) is... n For multi-factor index, air quality is taken as 1.2 to 1.4; By filling and venting the air chamber using the electromagnetic air valve (10), the pressure and volume of the air chamber are changed, thus increasing the equivalent instantaneous pressure Δ of the tailwater system. p eff (t)=Δ p h ( t )-Δ p g ( t ), where Δ p h ( t ) represents the original water hammer wave pressure, Δ p g ( t This is to regulate the pressure of the air chamber, ultimately achieving active compensation for pressure fluctuations.

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