A water hammer pump top cover drainage method based on dynamic volume control and double-pipe parallel connection

Abstract

The application provides a water hammer pump top cover drainage method based on dynamic volume control and double-pipe parallel connection, and the water hammer pump top cover drainage method based on dynamic volume control and double-pipe parallel connection can effectively solve problems such as limited top cover space of a hydropower station, high energy consumption and easy damage of mechanical parts, and realizes self-adaptive drainage control without external energy, reduces equipment failure rate and maintenance cost, and improves stability and operation safety of a drainage system.

Description

Technical Field

[0001] This invention relates to the field of drainage control for the top cover of a hydro-generator set, and more particularly to a drainage method for the top cover of a water hammer pump based on dynamic volume control and parallel connection of two pipes. Background Technology

[0002] In hydropower systems, roof drainage technology is a crucial element in ensuring stable unit operation and is widely used in the sealing and cooling systems of various hydro-turbine generator units. Related technologies typically employ a combination of electric drainage pumps and multi-stage water level control logic to construct a drainage system centered on mechanical drive. Specifically, this system encompasses the entire process from water level monitoring and pump start-up / shutdown control to drainage pipeline design, including key aspects such as water level sensor placement, control unit response, and pump selection and installation. As hydropower stations develop towards higher parameters and compact designs, the limited space of the roof is becoming increasingly prominent, posing serious challenges to traditional drainage systems in terms of energy consumption, reliability, and spatial adaptability.

[0003] However, existing top-cover drainage methods, which directly employ fixed-volume water storage chambers and single-pipe water intake structures, do not fully consider the impact of rotating flow fields on drainage efficiency, nor do they achieve dynamic matching between drainage capacity and water level changes. This may lead to problems such as exacerbated cavitation, increased vibration and noise, and frequent equipment start-ups and shutdowns. Specifically, since electric pumps rely on external power, their operating energy consumption is typically 5-10 kW. Under fluctuating water quality conditions, the shaft and blades are prone to cavitation, resulting in an average annual failure rate as high as 0.5 times, significantly increasing maintenance costs and downtime risks. Furthermore, due to space constraints in the top cover, some pumps cannot be installed, and drainage capacity can only be increased by adding more equipment, leading to an exponential increase in the complexity of the control system, making it difficult to meet the systemic requirements of modern hydropower stations for high reliability and low maintenance. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, the first objective of this invention is to propose a water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection.

[0006] The second objective of this invention is to propose a water hammer pump top cover drainage system based on dynamic volume control and dual-pipe parallel connection.

[0007] To achieve the above objectives, this invention proposes a method for draining water hammer pump top cover based on dynamic volume control and dual-pipe parallel connection, comprising: S1, based on the centrifugal head generated by the rotation of the turbine main shaft, calculates the equivalent head of the rotating water body in the annular area of ​​the top cover, which serves as the pressure driving source for the drainage system; S2 uses a parallel double-pipe structure to draw water, with the two pipes staggered by 180° along the direction of rotation and the center distance between the two pipes being 1.5 times the pipe diameter, in order to utilize the Coanda effect and Bernoulli effect to improve water intake efficiency and reduce turbulence intensity. S3 adopts an elastic corrugated tube water storage chamber structure. By adjusting the distance between the two ends of the water storage chamber with a stepper motor, the volume of the water storage chamber can be dynamically adjusted, thereby controlling the drainage volume in a closed loop. S4, combined with a dynamic volume control algorithm model, monitors the water level changes of the top cover in real time and calculates the target flow rate. Based on the target flow rate, it adjusts the volume of the elastic corrugated pipe water storage chamber to maintain the water level of the top cover within a set range.

[0008] The water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection in this invention embodiment may also have the following additional technical features: Preferably, the centrifugal head calculation calculates the kinetic energy of the rotating water body, including using the centrifugal pressure formula: (r≤x≤R) Calculate the centrifugal pressure distribution in the water body within the rotation radius r to R; The equivalent head is obtained by integrating the centrifugal pressure distribution over a circumferential region and taking the average value.

[0009] Substituting R=kr, we get:

[0010] ω is the angular velocity of the principal axis, g = 9.81 m / s² 2 This is the acceleration due to gravity.

[0011] Preferably, dynamic volume control includes: Determine the leakage flow rate: Top cover annular area :

[0012] k=R / r is the design diameter ratio of the top cover; Leakage flow : Calculate the target flow: Introduce proportional adjustment (ɑ=A / τ), τ represents the system response time. A smaller value results in a faster response, but oscillations must be avoided.

[0013] Calculate the volume of the water storage chamber: From the characteristic equation of the water hammer pump have to:

[0014] Substituting into the above calculation formula, we get: .

[0015] Preferably, in a dual-pipe parallel water supply system, the two pipes are staggered by 180° along the direction of rotation, with the long side of their vertical cut perpendicular to the main shaft, and vibration damping supports are installed on the outer wall of the top cover at certain intervals. According to the flow field velocity distribution formula:

[0016] Where: y is the vertical distance from the center of pipe 1, and s is the center distance between the two pipes. Single-pipe flow rate; Turbulent kinetic energy dissipation rate: k is the turbulent kinetic energy. When the distance between the two tubes is 1.5d, the turbulence intensity is reduced, and energy loss is decreased. Determine the maximum traffic requirement:

[0017] Vmin is the minimum volume of the water storage chamber, corresponding to the maximum drainage capacity; Calculate the diameter of a single pipe:

[0018] v c The critical cavitation velocity is used to ensure installation feasibility by constraining d≤0.3r. Center distance s between the two tubes: s = βd and 0.1r ≤ s ≤ 0.8(R) r) d β is a constraint coefficient that ensures the pipeline does not interfere within the top cover and effectively utilizes the centrifugal flow field. It is adjusted through on-site measurements.

[0019] Preferred vertical cut design, with dimensional specifications including: At a height h = 0.15d, the Reynolds number Re decreases from 10. 5 Reduced to 5×10 4 Turbulence intensity decreased by 40%; Width w=2d, ensuring the Strocha number St≈0.2 to avoid vortex-induced vibration; The aspect ratio h / w = 0.075 conforms to fluid dynamics and minimizes boundary layer separation.

[0020] Preferably, the water storage chamber structure employs an elastic corrugated tube, and the distance between the two ends of the water storage chamber is adjusted by a stepper motor to achieve dynamic adjustment of the water storage chamber volume, thereby achieving closed-loop control of the drainage volume. The structure also includes: S31 uses a stepper motor to drive the change in the distance between the two planes at both ends of the water storage chamber, allowing the metal bellows to extend and retract within the range of 0.5m to 2.0m, thereby achieving continuous adjustment of the water storage chamber volume; S32, set the depth-to-width ratio of the water storage chamber h / w = 0.075 to minimize boundary layer separation loss and improve water flow capture efficiency to over 90%.

[0021] To achieve the above objectives, another aspect of the present invention proposes a water hammer pump top cover drainage system based on dynamic volume control and dual-pipe parallel connection, comprising: The equivalent head calculation module is used to calculate the equivalent head of the rotating water body in the annular area of ​​the top cover based on the centrifugal head generated by the rotation of the turbine main shaft, which serves as the pressure driving source for the drainage system. The dual-pipe parallel water intake module is used to achieve water intake through a dual-pipe parallel structure, wherein the two pipes are staggered by 180° along the rotation direction and the center distance between the two pipes is 1.5 times the pipe diameter, so as to improve water intake efficiency and reduce turbulence intensity by utilizing the Coanda effect and Bernoulli effect. The dynamic volume adjustment module is used to dynamically adjust the volume of the water storage chamber by adjusting the distance between the two ends of the water storage chamber through a stepper motor, thereby achieving closed-loop control of the drainage volume. The water level stabilization control module is used to combine a dynamic volume control algorithm model to monitor the water level changes of the top cover in real time and calculate the target flow rate. Based on the target flow rate, the volume of the elastic corrugated pipe water storage chamber is adjusted to maintain the water level of the top cover within a set range.

[0022] The water hammer pump top cover drainage method and system based on dynamic volume control and dual-pipe parallel connection of the present invention can effectively solve the problems of limited space, high energy consumption and easy damage of mechanical parts in hydropower station top covers. By using the dual-pipe parallel connection structure and dynamic volume control, passive adaptive drainage is achieved, which significantly improves system stability and reduces operation and maintenance costs.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection according to an embodiment of the present invention; Figure 2This is an architectural diagram of a water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection according to an embodiment of the present invention. Figure 3 This is a structural diagram of a double-crown parallel water diversion system according to an embodiment of the present invention; Figure 4 This is a structural diagram of a water hammer pump top cover drainage system based on dynamic volume control and dual-pipe parallel connection according to an embodiment of the present invention. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0027] The following description, with reference to the accompanying drawings, illustrates a water hammer pump top cover drainage method and system based on dynamic volume control and dual-pipe parallel connection, according to an embodiment of the present invention.

[0028] Figure 1 This is a flowchart of a water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection according to an embodiment of the present invention, as follows: Figure 1 As shown, it includes: S1, based on the centrifugal head generated by the rotation of the turbine main shaft, calculates the equivalent head of the rotating water body in the annular area of ​​the top cover, which serves as the pressure driving source for the drainage system.

[0029] Specifically, in some implementations, the step of the present invention, "calculating the equivalent head of the rotating water body in the annular region of the top cover based on the centrifugal head generated by the rotation of the turbine main shaft, and using it as the pressure driving source of the drainage system," is a key step in realizing passive drainage control in the entire water hammer pump top cover drainage system. This step utilizes the centrifugal head formed in the annular region of the top cover when the turbine main shaft rotates to replace the external energy required by traditional electric drainage pumps, thereby achieving self-driven operation of the drainage system.

[0030] At the application level, this step is suitable for drainage control in the top cover area of ​​hydroelectric generator sets, especially in situations where space is limited, maintenance costs are high, and continuous operational stability is critical. Through dynamic calculation of centrifugal head, the system can respond in real time to changes in the turbine's operating status, achieving adaptive adjustment of drainage capacity.

[0031] The technical effect of this step is that by converting the rotational kinetic energy of the main shaft into a pressure drive source for the drainage system, the passive operation of the drainage system is realized, eliminating the risks of cavitation, vibration and blockage of traditional electric pumps, while improving drainage efficiency and system stability, and providing a strong guarantee for the safe operation of the turbine.

[0032] S2 employs a parallel double-pipe structure for water intake. The two pipes are staggered by 180° along the direction of rotation, and the center-to-center distance between them is 1.5 times the pipe diameter. This utilizes the Coanda and Bernoulli effects to improve water intake efficiency and reduce turbulence intensity. Specifically, the water intake step in this invention, achieved through a parallel double-pipe structure, is a key technical means to optimize the water intake efficiency of the top cover drainage system and reduce turbulence intensity, based on the synergistic effect of the Coanda effect and Bernoulli's principle in fluid mechanics. In some implementations, the double-pipe structure is arranged 180° off-center along the rotation direction of the turbine's main shaft, and the center-to-center distance between the two pipes is set to 1.5 times the pipe diameter (s=1.5d), thereby achieving efficient utilization of fluid dynamics within a limited space.

[0033] From a technical perspective, the parallel dual-pipe structure effectively reduces the flow load of a single pipe through a flow-diversion mechanism, avoiding cavitation and clogging problems caused by high flow velocities. The 180° staggered arrangement allows the water flow from the outlet of pipe 1 to adhere to the surface of pipe 2 under the action of centrifugal force, forming a boundary layer extension, thereby reducing fluid separation losses and improving water absorption efficiency (Coanda effect). Simultaneously, the high-speed flow region in pipe 1 forms a local low-pressure zone near pipe 2. According to Bernoulli's equation, this low-pressure zone helps enhance the water absorption capacity of pipe 2, achieving synergistic fluid efficiency.

[0034] In terms of parameter specifications, a center-to-center distance of s=1.5d between the two pipes is the optimal configuration verified by flow field simulation and field measurements, where d is the diameter of a single pipe. This distance effectively reduces the turbulent kinetic energy dissipation rate (ε), thereby reducing turbulence intensity. Furthermore, the pipe diameter design must satisfy d≤0.3r (r being the principal axis radius) to ensure installation feasibility within the limited space of the top cover. The vertical cutout design further optimizes the boundary layer characteristics of the fluid entering the water storage chamber; its height h=0.15d and width w=2d reduce the Reynolds number Re from 10... 5 Reduced to 5×10 4 The turbulence intensity is reduced by 40%, and the Strohar number St≈0.2, thus avoiding vortex-induced vibration.

[0035] In terms of application scenarios, this dual-pipe parallel structure is suitable for turbine top cover drainage systems, especially in situations where space is limited and water levels fluctuate frequently. It can replace traditional electric drainage pumps to achieve passive drainage and dynamic water level control. This structure works in conjunction with the elastic corrugated pipe water storage chamber and dynamic volume control algorithm to form a closed-loop regulation system, improving overall drainage efficiency and stability.

[0036] This step has significant technical benefits, not only improving water absorption efficiency (measured to over 90%, far exceeding the 85% of traditional horn-mouth structures), but also effectively suppressing energy loss and vibration risks caused by turbulence, thereby extending equipment lifespan and reducing maintenance costs. It provides an efficient, energy-saving, and stable solution for the turbine top cover drainage system.

[0037] In practical applications, this design is suitable for scenarios where the top cover space of a hydro-generator unit is limited, especially under high head and high flow conditions, effectively improving drainage efficiency and extending equipment life. This step, as the core of the fluid inlet control in the dual-pipe parallel structure, works in conjunction with the dynamic volume control algorithm model to achieve closed-loop regulation of the water level and optimization of drainage efficiency. This is a crucial technical support for the invention in terms of eliminating the need for external energy and reducing equipment dependence.

[0038] S3 adopts an elastic corrugated pipe water storage chamber structure. By adjusting the distance between the two ends of the water storage chamber with a stepper motor, the volume of the water storage chamber can be dynamically adjusted, thereby achieving closed-loop control of the drainage volume.

[0039] Specifically, the elastic corrugated pipe water storage chamber structure used in this invention dynamically adjusts the volume of the water storage chamber by adjusting the distance between the two ends of the water storage chamber using a stepper motor, thereby achieving closed-loop control of the drainage volume. This is one of the core actuators for achieving stable control of the top cover water level. This structure replaces the traditional electric drainage pump, effectively solving problems such as limited top cover space, high energy consumption, and equipment damage.

[0040] At the technical implementation level, the flexible bellows water storage chamber consists of rigid planes movable at both ends and a central metal bellows. The bellows possesses excellent axial compression and tensile properties while maintaining a tight seal. A stepper motor drives one end plane to move axially via a lead screw or linear guide mechanism, thereby changing the effective volume of the water storage chamber. When the water level at the top cover rises, the control system calculates the required drainage volume based on real-time water level sensor feedback signals and determines the target water storage chamber volume through a dynamic volume control algorithm model. This, in turn, controls the stepper motor's rotation angle and displacement to achieve precise adjustment of the water storage chamber volume.

[0041] In terms of parameters, the stepper motor typically has a step angle of 1.8° and a drive resolution of 0.01 mm / step to ensure adjustment accuracy. The initial volume of the water storage chamber can be set according to the design water level of the top cover, with an adjustment range generally within ±20% to adapt to drainage needs under different operating conditions. The opening and closing frequency of the water hammer pump pulse valve is matched with the change in the water storage chamber volume, usually controlled between 1 and 3 Hz to maintain a stable drainage flow and water hammer effect.

[0042] In application scenarios, this structure is suitable for the drainage system of a hydro-generator top cover, especially in conditions where space is limited and water levels fluctuate frequently. By working in conjunction with a dual-pipe parallel water intake system, it can effectively improve drainage efficiency and reduce the risks of cavitation and vibration. In actual installation, the water storage chamber should be located inside the top cover near the drain outlet to reduce water flow resistance and improve response speed.

[0043] The technical advantage of this step lies in achieving closed-loop control of drainage volume through dynamic adjustment of the water storage chamber, thereby maintaining the water level on the top cover within a set range and improving system stability. Compared to traditional drainage pumps, this solution requires no external power supply, reducing energy consumption and equipment failure rate, while also reducing maintenance workload, demonstrating significant engineering practical value and innovation.

[0044] Furthermore, S3 includes: S31 uses a stepper motor to drive the change in the distance between the two planes at both ends of the water storage chamber, allowing the metal bellows to extend and retract within the range of 0.5m to 2.0m, thereby achieving continuous adjustment of the water storage chamber volume.

[0045] Specifically, this step involves using a stepper motor to drive changes in the distance between the two planes at the ends of the water storage chamber, thereby enabling the metal bellows to expand and contract within a range of 0.5m to 2.0m, thus continuously adjusting the volume of the water storage chamber. This technique is the core actuator of the "dynamic volume control" module of this invention, used to respond to changes in the top cover water level, dynamically match drainage needs, and improve the adaptability and stability of the water hammer pump system.

[0046] In some implementations, a stepper motor is connected to the movable end plate of the water storage chamber via a lead screw drive mechanism or a rack and pinion structure, enabling precise control of the end plate's position. The motor drives the end plate to move axially, changing the length of the water storage chamber and thus adjusting its effective volume. The metal bellows, as an elastic sealing structure, is designed with a telescoping range of 0.5m to 2.0m to adapt to water storage requirements under different water level conditions. The preferred material for the bellows is 304 stainless steel, which possesses excellent corrosion resistance, elasticity, and sealing performance, meeting the long-term operational requirements of the hydropower station's roof environment.

[0047] The stepper motor's step angle is typically set to 1.8°, and with a microstepping driver, high-precision control of 0.09° can be achieved, ensuring the continuity and stability of the water storage chamber volume adjustment. The end plate's moving speed is controlled between 0.01m / s and 0.05m / s to avoid exacerbating the water hammer effect due to excessively rapid adjustment. The initial volume of the water storage chamber is preset based on the maximum leakage flow rate Vmax of the top cover. During adjustment, the volume parameters are corrected in real time through a closed-loop feedback system to ensure that drainage efficiency matches water level fluctuations.

[0048] In practical applications, this step is deployed in the drainage system of the top cover of the hydro-generator unit. A PLC or embedded controller receives water level sensor signals, calculates the required drainage volume, and drives a stepper motor to adjust the water storage chamber volume. This structure requires no continuous external power supply, consuming only a small amount of electricity during adjustment, significantly reducing the energy consumption and maintenance costs of traditional electric drainage pumps.

[0049] In terms of technical effectiveness, this step enables stepless adjustment of the water storage chamber volume, effectively matching drainage needs under different operating conditions and avoiding problems of excessively high or low water levels due to mismatched drainage capacity. Simultaneously, the elastic deformation of the metal bellows reduces internal system pressure fluctuations, lowers the risk of cavitation and vibration, and improves the operating efficiency and reliability of the water hammer pump. This technical approach has excellent installation adaptability in confined spaces and is the key innovation of this invention in achieving energy-saving, efficient, and stable drainage.

[0050] S32, set the depth-to-width ratio of the water storage chamber h / w = 0.075 to minimize boundary layer separation loss and improve water flow capture efficiency to over 90%.

[0051] Specifically, in this invention, the depth-to-width ratio of the water storage cavity is set. This is a crucial structural parameter design for achieving efficient drainage and minimizing boundary layer separation. This parameter directly affects the water flow capture efficiency and energy loss control of the water hammer pump in the top cover drainage system.

[0052] The water storage chamber adopts an elastic corrugated tube structure with a depth-to-width ratio of This refers to the effective height of the bellows. With width The ratio. By setting this ratio to 0.075, the geometry of the water storage cavity can be effectively controlled, giving it good dynamic volume adjustment capability under the action of water hammer waves. In some implementations, the width of the water storage cavity... Usually set to ,in The diameter is a single pipe to ensure sufficient lateral expansion space for the fluid as it enters the water storage chamber, thereby reducing flow resistance. Water storage chamber height... Then set to To match the water hammer wave propagation characteristics during the periodic opening and closing of the water hammer pump pulse valve, the water flow can stably adhere to the surface of the bellows after entering the water storage chamber, reducing boundary layer separation.

[0053] This design is based on the Coanda and Bernoulli effects in fluid mechanics, and optimizes the depth-to-width ratio to ensure the water storage cavity operates at a Reynolds number of [missing information]. This maintains laminar flow dominance, thereby reducing turbulence intensity by approximately 40%. Simultaneously, this ratio ensures the Stroja number... This avoids structural fatigue and energy loss caused by vortex-induced vibration. In practical engineering, the depth-to-width ratio of the water storage cavity... The settings need to be combined with the space constraints of the top cover and the pulse frequency of the water hammer pump, usually in Optimize within the scope and finally select The optimal value is to keep the water flow capture efficiency stable at over 90%.

[0054] This parameter setting is suitable for the top cover drainage system of hydro-generator units, especially under conditions of limited space and frequent water level fluctuations. Through the synergistic effect of the elastic corrugated pipe structure and the dynamic volume control algorithm, the water storage chamber can automatically adjust its volume under different water level conditions, thereby maintaining drainage efficiency and avoiding hydraulic losses or equipment damage caused by excessively high water levels.

[0055] This step effectively solves the energy loss problem caused by boundary layer separation in traditional drainage systems, improves the water hammer pump's suction and drainage efficiency, reduces the risk of vibration and cavitation caused by turbulence, and enhances the system's stability and reliability, thus having significant engineering practical value.

[0056] S4, combined with a dynamic volume control algorithm model, monitors the water level changes of the top cover in real time and calculates the target flow rate. Based on the target flow rate, it adjusts the volume of the elastic corrugated pipe water storage chamber to maintain the water level of the top cover within a set range.

[0057] Specifically, this step involves a water hammer pump top cover drainage control method based on a dynamic volume control algorithm model. Its core lies in real-time monitoring of top cover water level changes, calculating the target drainage flow rate using the algorithm model, and adjusting the volume of the elastic corrugated pipe storage chamber accordingly to achieve stable control of the top cover water level. This method replaces traditional electric drainage pumps during the operation of the hydro-generator unit, effectively reducing energy consumption and equipment failure rate.

[0058] At the technical implementation level, the system uses high-precision ultrasonic or pressure-type water level sensors deployed on the edge of the top cover to collect water level data in real time. A sampling frequency of at least 10 Hz is recommended to ensure rapid response to water level fluctuations. The dynamic volume control algorithm model is based on centrifugal head theory and fluid mechanics principles. By calculating the kinetic energy of the rotating water body and considering the deviation between the current water level and the set interval, a closed-loop control strategy is adopted to dynamically adjust the volume of the elastic bellows water storage chamber. This algorithm model introduces a proportional adjustment factor α = A / τ, where A is the current water level area and τ is the system response time, with a recommended range of 0.5 to 2.0 seconds to balance response speed and system stability.

[0059] The flexible corrugated water storage chamber consists of movable planes at both ends and a central metal corrugated pipe. Its volume change is driven by a stepper motor with a step angle accuracy of 0.9° and a response speed of up to 100 steps / second, thus achieving precise adjustment of drainage capacity. The water storage chamber volume calculation is based on the water hammer pump characteristic equation and leakage flow model. Combined with the current water level and the set range, the extension and retraction length of the corrugated pipe is dynamically adjusted to achieve a dynamic balance between drainage flow and top cover inlet flow.

[0060] This step is applicable to the top cover drainage system of hydro-generator units, especially suitable for hydropower station environments with limited space and requiring long-term stable operation. By eliminating reliance on electric pumps, the system can achieve passive drainage, reducing energy consumption and maintenance costs. Meanwhile, the flexible bellows structure has excellent sealing and pressure resistance, conforming to GB / T 151-2014 "Pressure Vessels" standard, and is suitable for operating conditions with water pressure ranging from 0.2 to 0.6 MPa.

[0061] This technical means plays a key role in the present invention. Through the coordinated control of algorithm model and mechanical structure, it achieves high-precision, low-energy consumption, and adaptive adjustment of the top cover water level, effectively improving the safety and stability of turbine operation.

[0062] The water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection of the present invention can effectively achieve dynamic and stable control of the water level on the top cover of the hydropower plant, reduce equipment failure rate and operation and maintenance costs, and at the same time significantly reduce the risks of cavitation, vibration and blockage through dual-pipe parallel connection and flexible corrugated pipe structure, thereby improving the operational reliability of the drainage system.

[0063] This invention aims to solve the problem of dynamic water level control in confined spaces, eliminate dependence on external energy sources, and address cavitation and vibration issues in single-pipe designs. Based on existing single-pipe fixed-volume water hammer pumps, a dual-pipe parallel design, a dynamic volume control algorithm model, and an elastic corrugated pipe storage tank technology are employed to achieve dynamic control of the top cover water level. Due to the limited space above the turbine top cover and insufficient flow from a single pipe, a dual-pipe design is necessary. Since water hammer pumps rely on water flow for work, their efficiency varies at different water levels above the top cover, requiring a variable storage space to control drainage efficiency. Compared to piston-type chambers or fixed chambers where volume is changed by inflating and deflating air bladders, which require more complex mechanisms, the elastic corrugated pipe storage tank only requires a few components such as a stepper motor and lead screw to achieve dynamic volume control. Figure 2 The diagram shown is an architectural diagram of the present invention.

[0064] The dynamic volumetric control algorithm model monitors water level fluctuations in real time, adjusts the optimal drainage volume in a closed loop, and dynamically adjusts the size of the storage chamber through a retractable corrugated pipe to control drainage efficiency. Its detailed model is as follows: Centrifugal head calculation: Calculate the kinetic energy of the rotating water body: Centrifugal pressure formula: (r≤x≤R) The equivalent head is averaged over the annular region:

[0065] Substituting R=kr, we get:

[0066] ω is the angular velocity of the principal axis (rad / s), g = 9.81 m / s² 2 This is the acceleration due to gravity.

[0067] Dynamic volume control: Determine the leakage flow rate: Top cover annular area : (Unit: m²) k=R / r is the design diameter ratio of the top cover, with a value ranging from 1.1 to 1.3, ensuring that the formula is effective in narrow spaces.

[0068] Leakage flow : (Unit: m³ / s) Calculate the target flow: Introducing proportional adjustment (ɑ=A / τ) τ is the system response time. The smaller the value, the faster the response, but oscillations should be avoided.

[0069]

[0070] Calculate the volume of the water storage chamber: From the characteristic equation of the water hammer pump have to

[0071] Substituting into the above calculation formula, we get

[0072] The dual-pipe parallel water intake system addresses spatial constraints by diverting and reducing pipe diameter, and improves efficiency through fluid synergy, thus resolving cavitation and blockage issues caused by single-pipe diameter exceeding limits (d>0.3r). The two pipes are arranged 180° off-center along the rotation direction, with their long sides of the vertical cut perpendicular to the main axis. Vibration-damping supports are installed on the outer wall of the top cover at certain intervals. The structure of the dual-pipe parallel water intake system is as follows: Figure 3 As shown, its detailed model is as follows: Flow field coordination effect: According to the flow field velocity distribution formula:

[0073] Where: y is the vertical distance from the center of pipe 1, and s is the center distance between the two pipes (optimal value 1.5d). The single-pipe flow rate is used to improve the water absorption efficiency of pipe 2.

[0074] Turbulence suppression mechanism: k is the turbulent kinetic energy. When the distance between the two tubes is 1.5d, the turbulence intensity is effectively reduced, and energy loss is minimized.

[0075] Pipe diameter calculation: Determine the maximum traffic requirement:

[0076] Vmin is the minimum volume of the water storage chamber, corresponding to the maximum drainage capacity.

[0077] Calculate the diameter of a single pipe:

[0078] v c The critical cavitation velocity is used to ensure installation feasibility by constraining d≤0.3r.

[0079] Center distance s between the two tubes: s = βd and 0.1r ≤ s ≤ 0.8(R) r) d β is a constraint coefficient that ensures the pipeline does not interfere within the top cover and effectively utilizes the centrifugal flow field. It is adjusted through on-site measurements.

[0080] At this time, the water flow at the outlet of pipe 1 adheres to the surface of pipe 2, reducing separation loss (Coanda effect), and the high-speed water flow in pipe 1 forms a low-pressure zone at pipe 2, improving water absorption efficiency (Bernoulli effect).

[0081] Vertical cut design: Size specifications: At a height h = 0.15d, the Reynolds number Re decreases from 10. 5 Reduced to 5×10 4 Turbulence intensity decreased by 40%; Width w=2d, ensuring the Strocha number St≈0.2 to avoid vortex-induced vibration; An aspect ratio of h / w = 0.075 conforms to fluid dynamics and minimizes boundary layer separation; To achieve the best centrifugal water capture rate (far exceeding 85% of the traditional funnel nozzle, with actual measurements exceeding 90%).

[0082] Furthermore, the water storage chamber of the water hammer pump is configured with an elastic bellows structure. The distance between one end of the water tank and the other end is controlled by a stepper motor, and a metal bellows is arranged between the two ends to form a sealed container. Water is stored by the water hammer wave generated by the periodic opening and closing of the pulse valve of the water hammer pump, and the water is discharged stably through the drain pipe.

[0083] This invention presents a water hammer pump top cover drainage method based on dynamic volume control and dual-pipe parallel connection, eliminating dependence on external energy and solving the cavitation and vibration problems of single-pipe designs. Building upon existing single-pipe fixed-volume water hammer pumps, it employs a dual-pipe parallel design, a dynamic volume control algorithm model, and elastic corrugated pipe water storage chamber technology to achieve dynamic control of the top cover water level. This method can replace various electric top cover drainage pumps, stabilize the top cover water level within a relatively small range, reduce equipment failure risks, decrease maintenance costs, and further improve the safe and stable operation of the turbine.

[0084] To achieve the above embodiments, such as Figure 4 As shown, this embodiment also provides a water hammer pump top cover drainage system 10 based on dynamic volume control and dual-pipe parallel connection, including: The equivalent head calculation module 100 is used to calculate the equivalent head of the rotating water body in the annular area of ​​the top cover based on the centrifugal head generated by the rotation of the turbine main shaft, and to serve as the pressure driving source of the drainage system. The dual-pipe parallel water intake module 200 is used to achieve water intake through a dual-pipe parallel structure, wherein the two pipes are staggered by 180° along the rotation direction and the center distance between the two pipes is 1.5 times the pipe diameter, so as to improve water intake efficiency and reduce turbulence intensity by utilizing the Coanda effect and Bernoulli effect. The dynamic volume adjustment module 300 is used to dynamically adjust the volume of the water storage chamber by adjusting the distance between the two ends of the water storage chamber through a stepper motor, thereby achieving closed-loop control of the drainage volume. The water level stabilization control module 400 is used to combine a dynamic volume control algorithm model to monitor the water level changes of the top cover in real time and calculate the target flow rate. Based on the target flow rate, the volume of the elastic corrugated pipe water storage chamber is adjusted to maintain the water level of the top cover within a set range.

[0085] This invention relates to a water hammer pump top cover drainage system based on dynamic volume control and dual-pipe parallel connection, eliminating dependence on external energy and solving the cavitation and vibration problems of single-pipe designs. Building upon existing single-pipe fixed-volume water hammer pumps, it employs a dual-pipe parallel design, a dynamic volume control algorithm model, and elastic corrugated pipe water storage chamber technology to achieve dynamic control of the top cover water level. This system can replace various electric top cover drainage pumps, stabilize the top cover water level within a relatively small range, reduce equipment failure risks, decrease maintenance costs, and further improve the safe and stable operation of the turbine.

[0086] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for draining water hammer pump top cover based on dynamic volume control and dual-pipe parallel connection, characterized in that, include: S1, based on the centrifugal head generated by the rotation of the turbine main shaft, calculates the equivalent head of the rotating water body in the annular area of ​​the top cover, which serves as the pressure driving source for the drainage system; S2 uses a parallel double-pipe structure to draw water, with the two pipes staggered by 180° along the direction of rotation and the center distance between the two pipes being 1.5 times the pipe diameter, in order to utilize the Coanda effect and Bernoulli effect to improve water intake efficiency and reduce turbulence intensity. S3 adopts an elastic corrugated tube water storage chamber structure. By adjusting the distance between the two ends of the water storage chamber with a stepper motor, the volume of the water storage chamber can be dynamically adjusted, thereby controlling the drainage volume in a closed loop. S4, combined with a dynamic volume control algorithm model, monitors the water level changes of the top cover in real time and calculates the target flow rate. Based on the target flow rate, it adjusts the volume of the elastic corrugated pipe water storage chamber to maintain the water level of the top cover within a set range.

2. The method as described in claim 1, characterized in that, Centrifugal head calculation, which calculates the kinetic energy of a rotating water body, including the use of centrifugal pressure formula: (r≤x≤R) Calculate the centrifugal pressure distribution in the water body within the rotation radius r to R; The equivalent head is obtained by integrating the centrifugal pressure distribution over a circumferential region and taking the average value. Substituting R=kr, we get: ω is the angular velocity of the principal axis, g = 9.81 m / s² 2 This is the acceleration due to gravity.

3. The method as described in claim 2, characterized in that, Dynamic volume control, including: Determine the leakage flow rate: Top cover annular area : k=R / r is the design diameter ratio of the top cover; Leakage flow : Calculate the target flow: Introduce proportional adjustment (ɑ=A / τ), τ represents the system response time. A smaller value results in a faster response, but oscillations should be avoided. Calculate the volume of the water storage chamber: From the characteristic equation of the water hammer pump have to: Substituting into the above calculation formula, we get: 。 4. The method as described in claim 3, characterized in that, The dual-pipe parallel water intake system has the two pipes staggered by 180° along the direction of rotation. The long side of their vertical cuts is perpendicular to the main shaft, and vibration damping supports are installed on the outer wall of the top cover at certain intervals. According to the flow field velocity distribution formula: Where: y is the vertical distance from the center of pipe 1, and s is the center distance between the two pipes. Single-pipe flow rate; Turbulent kinetic energy dissipation rate: k is the turbulent kinetic energy. When the distance between the two tubes is 1.5d, the turbulence intensity is reduced, and energy loss is decreased. Determine the maximum traffic requirement: Vmin is the minimum volume of the water storage chamber, corresponding to the maximum drainage capacity; Calculate the diameter of a single pipe: v c The critical cavitation velocity is used to ensure installation feasibility by constraining d≤0.3r. Center distance s between the two tubes: s = βd and 0.1r ≤ s ≤ 0.8(R r) d β is a constraint coefficient that ensures the pipeline does not interfere within the top cover and effectively utilizes the centrifugal flow field. It is adjusted through on-site measurements.

5. The method as described in claim 4, characterized in that, Vertical cut design, dimensional specifications include: At a height h = 0.15d, the Reynolds number Re decreases from 10. 5 Reduced to 5×10 4 Turbulence intensity decreased by 40%; Width w=2d, ensuring the Strocha number St≈0.2 to avoid vortex-induced vibration; The aspect ratio h / w = 0.075 conforms to fluid dynamics and minimizes boundary layer separation.

6. The method as described in claim 1, characterized in that, The water storage chamber structure employs an elastic corrugated tube, and the water storage chamber volume is dynamically adjusted by using a stepper motor to regulate the distance between the two ends of the water storage chamber, thereby achieving closed-loop control of the drainage volume. It also includes: S31 uses a stepper motor to drive the change in the distance between the two planes at both ends of the water storage chamber, allowing the metal bellows to extend and retract within the range of 0.5m to 2.0m, thereby achieving continuous adjustment of the water storage chamber volume; S32, set the depth-to-width ratio of the water storage chamber h / w = 0.075 to minimize boundary layer separation loss and improve water flow capture efficiency to over 90%.

7. A water hammer pump top cover drainage system based on dynamic volume control and dual-pipe parallel connection, characterized in that, include: The equivalent head calculation module is used to calculate the equivalent head of the rotating water body in the annular area of ​​the top cover based on the centrifugal head generated by the rotation of the turbine main shaft, which serves as the pressure driving source for the drainage system. The dual-pipe parallel water intake module is used to achieve water intake through a dual-pipe parallel structure, wherein the two pipes are staggered by 180° along the rotation direction and the center distance between the two pipes is 1.5 times the pipe diameter, so as to improve water intake efficiency and reduce turbulence intensity by utilizing the Coanda effect and Bernoulli effect. The dynamic volume adjustment module is used to dynamically adjust the volume of the water storage chamber by adjusting the distance between the two ends of the water storage chamber through a stepper motor, thereby achieving closed-loop control of the drainage volume. The water level stabilization control module is used to combine a dynamic volume control algorithm model to monitor the water level changes of the top cover in real time and calculate the target flow rate. Based on the target flow rate, the volume of the elastic corrugated pipe water storage chamber is adjusted to maintain the water level of the top cover within a set range.

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