Hydraulic turbine balance pipe and flow regulating method thereof, hydraulic turbine

Abstract

The present application relates to the technical field of water turbine, and especially relates to a water turbine balance pipe, a flow regulating method thereof, and a water turbine. The water turbine balance pipe comprises a balance pipe body, a valve body and a regulating mechanism. The balance pipe body is provided with a variable diameter section. The valve body is arranged in the variable diameter section of the balance pipe body. The gap between the outer surface of the valve body and the inner wall of the balance pipe body constitutes a flow passage. The regulating mechanism is connected to the valve body. In the present application, the valve body moves in the variable diameter section of the balance pipe body. When the fluid passes through the balance pipe, the flow changes at the valve body, and the local resistance is generated, thereby affecting the velocity and pressure distribution of the fluid. By reasonably selecting the position of the valve body in the variable diameter section of the balance pipe body, the flow and pressure of the fluid can be controlled under different working conditions. The factors affecting the stability of the unit, such as the leakage flow, pressure loss and axial force of the water turbine, are balanced, the leakage flow between the runner and the top cover is reduced, and the appropriate gap cavity pressure is maintained.

Description

Technical Field

[0001] This invention relates to the field of water turbine technology, and in particular to a water turbine balance pipe and its flow regulation method, and a water turbine. Background Technology

[0002] As a crucial piece of hydroelectric power generation equipment, the operational stability of a water turbine directly impacts the reliability and efficiency of the entire power supply system. Mixed-flow turbines, also known as Francis turbines, are a type of reaction turbine. The main components of a mixed-flow turbine include the spiral casing, bearing ring, guide vane mechanism, top cover, runner, main shaft, guide bearing, bottom ring, and draft tube. The runner consists of an upper crown, lower ring, and several fixed blades. The draft tube is the turbine's exhaust system that directs the water flow from the runner outlet downstream.

[0003] In mixed-flow turbine systems, to reduce leakage losses between the runner and stationary components, a leak-proof ring is typically installed in the cavity formed by the runner's crown and top cover. Because the fluid pressure in the cavity between the runner and top cover is unbalanced with the fluid pressure inside the runner, axial hydraulic thrust is generated on the rotating components during turbine operation. A balancing pipe is needed to connect the crown cavity and the tailrace pipe to achieve pressure balance. Existing balancing pipes are generally conventional pipe structures, mostly pre-embedded in concrete.

[0004] Research has revealed that, in addition to the gap size of the sealing ring, the diameter of the balancing pipe also significantly affects the flow rate, leakage, and axial force of the turbine runner. However, since most sections of the balancing pipe need to be embedded in concrete, and its diameter is generally determined empirically based on the specific speed and size of the turbine runner, once the power plant is built, the diameter of the embedded balancing pipe and the gap size of the sealing ring are fixed. This fixed dimensional fit leads to excessive leakage or excessive axial force at operating points other than the design point, which in severe cases can cause unit vibration or shaft damage. Summary of the Invention

[0005] This invention provides a turbine balance pipe and its flow regulation method, as well as a turbine, to solve the defects of existing turbine balance pipes with fixed diameters, which easily lead to excessive leakage or excessive or insufficient axial force (causing turbine lift) at operating points other than the design point. It achieves effective control of the pressure and leakage of the gap cavity, and ensures that the overall axial force of the unit is stable and controllable. It can reduce the amount of air supplied to the unit, thereby reducing pressure pulsation and noise, reducing the unit's operating energy consumption and water consumption, and improving the unit's efficiency.

[0006] This invention provides a turbine balance pipe, comprising a balance pipe body, a valve body, and an adjusting mechanism. One end of the balance pipe body is connected to the upper crown clearance cavity of the turbine, and the other end is connected to the turbine's tailrace pipe. The balance pipe body has a variable diameter section, in which the inner diameter of the balance pipe body gradually decreases or gradually increases. The valve body is disposed within the variable diameter section of the balance pipe body, and the gap between the outer surface of the valve body and the inner wall of the balance pipe body constitutes the flow passage of the turbine balance pipe. The adjusting mechanism is connected to the valve body and is adapted to push the valve body to move in the variable diameter section to change the flow area of ​​the flow passage of the turbine balance pipe.

[0007] According to the present invention, a turbine balance pipe is provided, wherein the valve body is a spindle-shaped streamlined valve body, and the maximum diameter of the valve body is smaller than the minimum diameter of the variable diameter section of the balance pipe body.

[0008] According to the present invention, the maximum diameter of the valve body of a turbine balance pipe satisfies the following condition: In the formula, Indicates the maximum diameter of the valve body. This indicates the minimum diameter of the variable diameter section of the balanced pipe body. This indicates the maximum diameter of the variable diameter section of the balance pipe body. This indicates the inclination length of the variable diameter section of the balance pipe. This indicates the inclination angle of the variable diameter section of the balance pipe.

[0009] According to the present invention, a turbine balance pipe includes a first straight pipe, a bend, and a second straight pipe. The first end of the first straight pipe is connected to the turbine's tailrace pipe via a sealing flange. The first end of the first straight pipe has a conical structure to form the variable diameter section. The first end of the bend is connected to the second end of the first straight pipe via a sealing flange. An adjustment mechanism is disposed in the bend and oriented towards the first straight pipe. The first end of the second straight pipe is connected to the second end of the bend via a sealing flange. The second end of the second straight pipe is connected to the turbine's upper crown clearance cavity via a sealing flange.

[0010] According to the present invention, a turbine balance pipe is provided, wherein the adjusting mechanism includes a connecting seat, a connecting rod, and a driving device. The connecting seat is fixed on the bend, and a connecting channel coaxial with the axis of the first straight pipe is formed inside the connecting seat, the connecting channel communicating with the bend. The connecting rod passes through the connecting channel of the connecting seat and the bend, and the first end of the connecting rod is connected to the valve body. The driving device is connected to the second end of the connecting rod and is adapted to drive the connecting rod to move along the axis of the first straight pipe to adjust the position of the valve body inside the first straight pipe.

[0011] According to the present invention, a turbine balance pipe is provided, wherein the connecting seat includes a connecting sleeve, a connecting end cap, a sealing element, and a sealing filler. The first end of the connecting sleeve is welded to the bend, and the second end of the connecting sleeve is provided with a stepped hole. The connecting sleeve is coaxially arranged with the first straight pipe. The connecting end cap is detachably connected to the stepped hole at the second end of the connecting sleeve. The connecting end cap has a through hole at its center, which is suitable for passing the connecting rod sequentially through the through hole at the center of the connecting end cap, the connecting sleeve, and the bend. The sealing element is disposed in the gap between the connecting rod and the connecting sleeve. The sealing filler fills the space between the connecting end cap and the stepped hole at the second end of the connecting sleeve.

[0012] The present invention also provides a method for regulating the flow rate of a turbine balance pipe, applicable to adjusting the flow area of ​​the turbine balance pipe described in any of the above-mentioned embodiments, the method comprising:

[0013] Numerical simulations of the fluid flow in the main flow channel, upper crown cavity, lower ring cavity, leak-stop ring, and balance pipe of the water turbine were performed to simulate different operating conditions of the water turbine.

[0014] In the simulation of the first operating point of the turbine, the position of the valve body in the variable diameter section of the balance pipe is changed by adjusting the mechanism to change the flow area of ​​the balance pipe. The turbine runner axial force and the leakage between the runner and stationary parts are obtained under different flow areas, forming a test set. Based on the formed test set, the valve body position corresponding to the turbine runner axial force and the leakage between the runner and stationary parts under the optimal condition at the first operating point of the turbine is obtained by an optimization algorithm.

[0015] By changing the simulated operating point of the turbine, the position of the valve body in the variable diameter section of the balance pipe is changed again through the adjustment mechanism. The axial force of the turbine runner and the leakage between the runner and the stationary parts at other operating points of the turbine are obtained respectively, and the valve body position is obtained under the optimal condition.

[0016] The axial force of the impeller at all operating points and the leakage between the impeller and stationary parts are integrated to form a dataset corresponding to the valve body position under the optimal condition.

[0017] During the actual operation of the turbine, the position of the valve body in the variable diameter section of the balance pipe is adjusted based on the dataset to change the flow area of ​​the balance pipe, so as to keep the axial force of the turbine runner and the leakage between the runner and stationary parts in the optimal state.

[0018] According to a method for regulating the flow rate of a turbine balance pipe provided by the present invention, during the actual operation of the turbine, the position of the valve body within the variable diameter section of the balance pipe body is adjusted based on the dataset. This adjustment is performed using an automatic control process, which includes: storing the dataset in a data table in the turbine power station control system; and the turbine power station control system automatically controlling the regulating mechanism to adjust the position of the valve body based on the dataset to match the actual operating conditions of the turbine.

[0019] According to a method for regulating the flow rate of a turbine balance pipe provided by the present invention, during the actual operation of the turbine, the position of the valve body within the variable diameter section of the balance pipe body is adjusted based on the dataset. This adjustment is performed manually. The manual control process includes: classifying the dataset according to the turbine operating conditions, forming multiple adjustment level indicator keys on the regulating mechanism, with different adjustment level indicator keys corresponding to different turbine operating conditions; and manually adjusting the corresponding adjustment level indicator keys on the regulating mechanism based on the actual operating conditions of the turbine to match the actual operating conditions of the turbine.

[0020] The present invention also provides a water turbine, including the water turbine balance pipe described in any one of the above claims, or capable of performing the water turbine balance pipe flow regulation method described in any one of the above claims.

[0021] The turbine balance pipe provided by this invention features a variable-diameter section within the pipe body, and a valve body movably positioned within this section. The changing position of the valve body within this section causes flow rate changes at the valve body, generating local resistance and affecting the fluid's velocity and pressure distribution. By strategically selecting the valve body's position within the variable-diameter section, the flow rate and pressure of the fluid can be controlled under different operating conditions. This balances multiple factors affecting unit stability, such as turbine leakage flow, pressure loss, and axial force, reducing leakage flow between the runner and the top cover, maintaining appropriate clearance chamber pressure, and also reducing the need for top cover air supply. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of the turbine balance pipe provided by the present invention.

[0024] Figure 2 This is a schematic diagram of the fit structure between the valve body and the variable diameter section of the balance pipe provided by the present invention.

[0025] Figure 3 This is a schematic diagram of the valve body provided by the present invention.

[0026] Figure label:

[0027] 1. Balance pipe body; 11. First straight pipe; 12. Bend; 13. Second straight pipe; 2. Valve body; 3. Adjustment mechanism; 31. Connecting seat; 311. Connecting sleeve; 312. Connecting end cap; 313. Seal; 314. Sealing packing; 32. Connecting rod; 33. Drive device. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0031] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0032] 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.

[0033] The following is combined with Figures 1 to 3 The present invention describes a turbine balance pipe and its flow regulation method, and a turbine.

[0034] One embodiment of the present invention provides a turbine balance pipe, see below. Figure 1 As shown, the turbine balance pipe includes a balance pipe body 1, a valve body 2, and an adjusting mechanism 3. One end of the balance pipe body 1 is connected to the upper crown clearance cavity of the turbine, and the other end is connected to the turbine's tailrace pipe. The balance pipe body 1 is provided with a diameter-changing section, in which the inner diameter of the balance pipe body 1 gradually decreases or gradually increases. The valve body 2 is located in the diameter-changing section of the balance pipe body 1, and the gap between the outer surface of the valve body 2 and the inner wall of the balance pipe body 1 constitutes the flow passage of the turbine balance pipe. The adjusting mechanism 3 is connected to the valve body 2 and is adapted to push the valve body 2 to move in the diameter-changing section to change the flow area of ​​the flow passage of the turbine balance pipe.

[0035] It is understood that the turbine balance pipe provided in this embodiment, by setting a variable diameter section in the balance pipe body 1 and movably setting a valve body 2 within the variable diameter section, causes a flow rate change at the valve body 2 when the fluid passes through the balance pipe, generating local resistance and thus affecting the fluid velocity and pressure distribution. By reasonably selecting the position of the valve body 2 within the variable diameter section of the balance pipe body 1, the flow rate and pressure of the fluid can be controlled under different operating conditions, balancing multiple factors affecting the stability of the unit such as turbine leakage flow, pressure loss, and axial force, reducing leakage flow between the runner and the top cover, maintaining appropriate gap cavity pressure, and also reducing the need for top cover air supply.

[0036] In some embodiments of the turbine balance pipe of the present invention, the valve body 2 is a spindle-shaped streamlined valve body, and the maximum diameter of the valve body 2 is smaller than the minimum diameter of the variable diameter section of the balance pipe body 1. The maximum diameter of the valve body 2 satisfies: In the formula, Indicates the maximum diameter of the valve body. This indicates the minimum diameter of the variable diameter section of the balanced pipe body. This indicates the maximum diameter of the variable diameter section of the balance pipe body. This indicates the inclination length of the variable diameter section of the balance pipe. This indicates the inclination angle of the variable diameter section of the balance pipe.

[0037] It is understood that the valve body 2 in this embodiment is a spindle-shaped streamlined valve body. The spindle-shaped streamlined valve body moves along the axial direction of the balance pipe body 1 in the variable diameter section. The flow passage formed between the outer surface of the spindle-shaped streamlined valve body and the inner wall of the balance pipe body 1 changes in flow area as the valve body 2 moves. As a result, when the fluid passes through the balance pipe, the flow rate changes at the valve body 2, generating local resistance and affecting the velocity and pressure distribution of the fluid.

[0038] The diameter distribution of the spindle-shaped streamlined valve body conforms to a specific axial distribution pattern, allowing adjustment of the flow area of ​​the balance pipe based on the position of valve body 2, thereby regulating the flow rate through the balance pipe and the pressure distribution within the cavity. (See also...) Figure 2 As shown, the maximum diameter of the spindle-shaped streamlined valve body can be defined by the following formula:

[0039]

[0040] Based on the above two sets of formulas, the maximum diameter of valve body 2 satisfies: In the formula, Indicates the maximum diameter of the valve body. This indicates the minimum diameter of the variable diameter section of the balanced pipe body. This indicates the maximum diameter of the variable diameter section of the balance pipe body. This indicates the inclination length of the variable diameter section of the balance pipe. This indicates the inclination angle of the variable diameter section of the balance pipe.

[0041] Further, see Figure 3 As shown, the spindle-shaped streamlined valve body can be divided into 10 equal segments along the axial direction, with each segment having a length of: In the formula, The total length of the spindle body. The length of each segment of the spindle-shaped streamlined valve body is given, and all segments are of equal length. The inclination angle of the variable-diameter section of the balance pipe body is taken as... The angle is 10°, and the streamlined spindle-shaped valve body is... segment diameter With axial position The change can be calculated using the following formula:

[0042]

[0043]

[0044] The axial diameter of the resulting spindle-shaped streamlined valve body is shown in the table below:

[0045]

[0046] Based on the table above, this embodiment divides the spindle-shaped streamlined valve body into 10 equal segments along the axial direction, thus forming 9 working positions of the spindle-shaped streamlined valve body, corresponding sequentially to... Each working position corresponds to a valve body diameter. By adjusting the axial position of the spindle-shaped streamlined valve body, the position of valve body 2 within the variable diameter section of the balance pipe body 1 is changed, thereby altering the flow area of ​​the turbine balance pipe's flow passage.

[0047] In some embodiments of the turbine balance pipe of the present invention, see again Figure 1 As shown, the balance pipe body 1 includes a first straight pipe 11, a bend 12, and a second straight pipe 13. The first end of the first straight pipe 11 is connected to the tailrace pipe of the turbine through a sealing flange. The first end of the first straight pipe 11 has a conical structure to form a variable diameter section. The first end of the bend 12 is connected to the second end of the first straight pipe 11 through a sealing flange. The adjusting mechanism 3 passes through the bend 12 and is arranged towards the first straight pipe 11. The first end of the second straight pipe 13 is connected to the second end of the bend 12 through a sealing flange. The second end of the second straight pipe 13 is connected to the upper crown clearance cavity of the turbine through a sealing flange.

[0048] Understandably, in this embodiment, the first end of the first straight pipe 11 is designed as a conical structure, forming a variable diameter section. This design helps to generate a certain pressure change when the fluid enters the balance pipe, thereby affecting flow control. The regulating mechanism 3 passes through the bend 12 and is positioned towards the first straight pipe 11. This means that the regulating mechanism 3 can directly act on the valve body 2 located inside the first straight pipe, thereby adjusting the area of ​​the flow passage. The second straight pipe 13 ensures smooth fluid flow from the tailrace pipe to the upper crown gap cavity, and the fluid flow characteristics in this process can be optimized by changing the position of the valve body 2 through the regulating mechanism 3. The combined use of the above components in this embodiment allows for precise control of the water flow velocity and pressure distribution through the balance pipe through the regulating mechanism 3, thereby effectively managing leakage and axial force during turbine operation. This not only improves the flexibility and adaptability of the system but also enhances the overall performance and reliability of the equipment. In addition, the use of sealing flanges ensures the sealing of each connection point, reducing the potential risk of leakage.

[0049] The balance pipe body 1 and the sealing flange are made of high-carbon steel, and the sealing flange uses a PTFE sealing ring, ensuring the system's durability and sealing performance. Under certain special operating conditions, the selection of materials for the balance pipe body 1 and the sealing flange is crucial for the long-term operational stability of the system. Bolt connections can be used at the joints, with high-strength stainless steel hexagonal bolts to enhance structural strength and reliability, thereby effectively extending the service life of the turbine balance pipe.

[0050] In some embodiments of the turbine balance pipe of the present invention, the adjusting mechanism 3 includes a connecting seat 31, a connecting rod 32, and a driving device 33. The connecting seat 31 is fixed on the bend 12, and a connecting channel coaxial with the axis of the first straight pipe 11 is formed in the connecting seat 31. The connecting channel communicates with the bend 12. The connecting rod 32 passes through the connecting channel of the connecting seat 31 and the bend 12. The first end of the connecting rod 32 is connected to the valve body 2. The driving device 33 is connected to the second end of the connecting rod 32 and is adapted to drive the connecting rod 32 to move along the axis of the first straight pipe 11 to adjust the position of the valve body 2 in the first straight pipe 11.

[0051] Understandably, the connecting seat 31 has a connecting channel coaxial with the axis of the first straight pipe 11. This connecting channel not only communicates with the bend 12 but also provides the necessary installation and operating space for subsequent components. The connecting rod 32 passes through the connecting channel of the connecting seat 31 and the bend 12. The first end of the connecting rod 32 is directly connected to the valve body 2, which allows the position of the valve body 2 to be indirectly controlled by moving the connecting rod 32. The driving device 33 can push the connecting rod 32 to reciprocate along the axis of the first straight pipe 11. This movement can change the specific position of the valve body 2 within the first straight pipe 11, thereby achieving precise adjustment of the flow channel area.

[0052] When the flow rate within the turbine's balance pipe needs adjustment, the drive unit 33 is activated. This drives or pulls the connecting rod 32, causing its connected spindle-shaped streamlined valve body 2 to move axially within the first straight pipe 11. Because the first end of the first straight pipe 11 is designed as a conical structure (variable diameter section), the valve body 2 affects the flow area at different positions, thereby controlling the water flow velocity and pressure distribution through the balance pipe. In this way, leakage and axial force during turbine operation can be effectively managed, optimizing equipment performance.

[0053] It should be understood that the driving device 33 in this embodiment can be a drive motor, and the connecting rod 32 can be adjusted by extension (the driving device 33 is a linear motor) or by helical connection (the driving device 33 is a rotary motor) to realize the electric axial movement adjustment of the connecting rod 32; the driving device 33 can also be a push-pull device, which is suitable for realizing the axial movement of the connecting rod 32 by manual push-pull.

[0054] Furthermore, the connecting seat 31 includes a connecting sleeve 311, a connecting end cap 312, a sealing element 313, and a sealing filler 314. The first end of the connecting sleeve 311 is welded to the bend 12, and the second end of the connecting sleeve 311 is provided with a stepped hole. The connecting sleeve 311 is coaxially arranged with the first straight pipe 11. The connecting end cap 312 is detachably connected to the stepped hole at the second end of the connecting sleeve 311. The connecting end cap 312 is provided with a through hole at its center, which is suitable for the connecting rod 32 to pass through the through hole at the center of the connecting end cap 312, the connecting sleeve 311, and the bend 12 in sequence. The sealing element 313 is disposed in the gap between the connecting rod 32 and the connecting sleeve 311. The sealing filler 314 fills the space between the connecting end cap 312 and the stepped hole at the second end of the connecting sleeve 311.

[0055] The second end of the connecting sleeve 311 is provided with a stepped hole for installing the connecting end cap 312. The connecting sleeve 311 is coaxially arranged with the first straight pipe 11, ensuring smooth and consistent fluid passage. The connecting end cap 312 has a through hole at its center, allowing the connecting rod 32 to pass through this hole, the connecting sleeve 311, and the bend 12 in sequence, thereby achieving drive control of the valve body 2. A sealing element 313 is disposed in the gap between the connecting rod 32 and the connecting sleeve 311 to prevent fluid leakage and ensure system sealing. It is typically an O-ring or other type of gasket, with the appropriate material and shape selected according to the specific application. Sealing packing 314 fills the space between the stepped hole at the second end of the connecting end cap 312 and the connecting sleeve 311, further enhancing the sealing effect. Sealing packing 314 not only prevents fluid leakage but also compensates for minor displacements caused by temperature changes or mechanical vibrations, maintaining long-term sealing performance. This embodiment, by using sealing element 313 and sealing packing 314, enables the device to maintain good sealing performance under high pressure and high temperature conditions, preventing fluid leakage. The detachable design of the connecting end cap 312 facilitates maintenance and replacement of internal components, reducing downtime. The connecting rod 32, through a through hole and connecting sleeve 311, ensures accurate movement, thereby achieving precise control of the valve body 2's position and optimizing flow regulation. This detailed connecting seat 31 design not only enhances the system's sealing and reliability but also improves operational precision and maintainability. The tight fit between components ensures the stable operation of the entire regulating mechanism 3, contributing to improved overall turbine performance and efficiency. In particular, the application of seals 313 and sealing packing 314 is crucial for ensuring the system's long-term stable operation.

[0056] In another aspect, the present invention provides a method for regulating the flow rate of a turbine balance pipe, applicable to adjusting the flow area of ​​the turbine balance pipe in any of the above embodiments. In some specific embodiments, the method for regulating the flow rate of a turbine balance pipe includes: performing numerical simulation of the turbine fluid flow in the main flow channel, upper crown cavity, lower ring cavity, leak-proof ring, and balance pipe of the turbine, simulating different operating points of the turbine. Under the simulation of the first operating point of the turbine, the position of the valve body 2 in the variable diameter section of the balance pipe body 1 is changed by the adjustment mechanism 3 to change the flow area of ​​the balance pipe body 1, obtaining the turbine runner axial force and the leakage between the runner and stationary components corresponding to different flow areas of the balance pipe body 1, forming a test set, and obtaining the position of the valve body 2 corresponding to the turbine runner axial force and the leakage between the runner and stationary components under the optimal condition under the first operating point of the turbine through an optimization algorithm based on the formed test set. By changing the simulated operating point of the turbine, the position of valve body 2 within the variable diameter section of the balance pipe 1 is changed again via the adjusting mechanism 3. The optimal positions of valve body 2 for the turbine runner axial force and leakage between the runner and stationary components at other operating points are then obtained. These optimal valve body 2 positions for all operating points are integrated into a dataset. During actual turbine operation, the position of valve body 2 within the variable diameter section of the balance pipe 1 is adjusted based on this dataset to change the flow area of ​​the balance pipe 1, thereby maintaining the optimal state of the turbine runner axial force and leakage between the runner and stationary components.

[0057] It is understandable that the turbine balance pipe flow regulation method in this embodiment is based on a series of fluid flow numerical simulation experiments, recording the axial position of the spindle-shaped streamlined valve body under different operating conditions. ), Changes in flow area and axial force of impeller ( ) and leakage amount ( The relationship between the two is used to construct a dataset based on the simulation results. and To determine each working condition (opening degree) Optimal valve body position under power N) The corresponding working positions of valve body 2 are as follows: This method dynamically adjusts the position of valve body 2 to optimize the flow field distribution within the pipe, thereby achieving a reasonable balance between axial force and leakage, effectively reducing pressure pulsation and noise, and improving the stability and efficiency of unit operation.

[0058] Furthermore, during the actual operation of the turbine, the position of the valve body 2 within the variable diameter section of the balance pipe 1 can be adjusted based on the dataset. This can be achieved through automatic or manual control. By manually or automatically adjusting the position of the spindle-shaped streamlined valve body inside the turbine balance pipe, the impedance of the turbine balance pipe can be adjusted.

[0059] In some specific examples, the position of the valve body 2 within the variable diameter section of the balance pipe body 1 is determined by an automatic control process. The automatic control process includes: storing the dataset in the form of a data table in the turbine power station control system; and the turbine power station control system automatically controlling the regulating mechanism 3 to adjust the position of the valve body 2 based on the dataset to match the actual operating conditions of the turbine.

[0060] Understandably, the automatic control process includes data storage and automatic adjustment mechanisms. The dataset obtained through numerical simulation and optimization algorithms is stored in the turbine power station control system in the form of a data table. This data includes the optimal position of valve body 2 under different operating conditions, along with the corresponding axial force and leakage of the runner. The turbine power station control system is integrated with the regulating mechanism 3, enabling real-time monitoring of the turbine's actual operating conditions. Based on the current conditions, the control system automatically retrieves the relevant data and automatically adjusts the position of valve body 2 through the regulating mechanism 3 to ensure its flow area is always at its optimal state. The turbine power station control system can dynamically adjust according to real-time monitored changes in operating conditions, ensuring that the turbine maintains optimal performance under various operating conditions.

[0061] Assuming the turbine is gradually transitioning from low load to high load: the turbine power station control system monitors the load increase in real time and identifies the current operating condition as being within the high load range. The system automatically retrieves the optimal valve body 2 position data corresponding to the high load condition from the dataset. The position of valve body 2 is automatically adjusted via the regulating mechanism 3 to achieve the optimal flow area of ​​the balance pipe, thereby optimizing the axial force and leakage of the runner.

[0062] In some other specific examples, the position of the entire valve body 2 within the variable diameter section of the balance pipe body 1 is controlled manually. The manual control process includes: classifying the dataset according to the turbine operating conditions, forming multiple adjustment level indicator keys on the regulating mechanism 3, with different adjustment level indicator keys corresponding to different turbine operating conditions; and manually adjusting the corresponding adjustment level indicator keys on the regulating mechanism 3 based on the actual operating conditions of the turbine to match the actual operating conditions of the turbine.

[0063] Understandably, the manual control process requires first classifying the data on the regulating mechanism 3, dividing the dataset into levels according to the turbine's operating conditions. For example, the operating conditions can be divided into different ranges such as low load, medium load, and high load. Multiple adjustment level indicator keys are formed on the regulating mechanism 3, each corresponding to a specific operating condition range. These indicators are used to quickly select the appropriate valve body 2 position. Based on the turbine's current actual operating conditions, the corresponding adjustment level indicator key is manually adjusted on the regulating mechanism 3. For example, if the turbine is currently under high load, the operator can select the corresponding high load adjustment level indicator key. Through the preset adjustment level indicator keys, the operator can quickly find and adjust to the optimal valve body 2 position, reducing human error and adjustment time.

[0064] Suppose the turbine needs to switch from normal operation to emergency load mode: The operator observes that the turbine is about to enter emergency load mode and determines that the current operating condition falls within the emergency load range. The operator locates and presses the corresponding emergency load adjustment indicator key on the regulating mechanism 3. The regulating mechanism 3 adjusts the position of the valve body 2 according to preset data to ensure good performance even under emergency load conditions.

[0065] Whether using automatic or manual control, the turbine balance pipe flow regulation method provided by this invention can effectively optimize the turbine's operating performance. Automatic control is suitable for scenarios requiring high precision and rapid response, while manual control offers greater flexibility and simplicity, suitable for specific operational needs. Combining the two control methods further improves the system's reliability and adaptability, ensuring the turbine maintains optimal performance under various operating conditions.

[0066] This invention also provides a turbine, including a turbine balance pipe according to any of the above embodiments, or capable of executing the turbine balance pipe flow regulation method according to any of the above embodiments. It is understood that the turbine provided by this invention, by including the aforementioned turbine balance pipe, possesses the flow regulation function of the turbine balance pipe. The turbine balance pipe can be used not only in designed mixed-flow conventional units and pumped-storage units, but also, especially for power plant units under construction and already built, its top cover design is simple, allowing for quick disassembly and installation, facilitating maintenance and replacement, and reducing system downtime. At the same time, the dynamic regulation function of the balance pipe can effectively cope with pressure changes under different operating conditions, optimize the turbine's operating performance, further improve system efficiency, reduce operating costs, and ensure the long-term stable operation of the turbine.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic turbine balance pipe, characterized by, The utility model relates to a balance pipe for hydraulic turbine, which comprises: a balance pipe body (1) connected to the upper crown gap cavity of the hydraulic turbine at one end and to the draft tube of the hydraulic turbine at the other end, wherein the balance pipe body (1) is provided with a variable diameter section, at which the inner diameter of the balance pipe body (1) gradually decreases or increases; a valve body (2) arranged in the variable diameter section of the balance pipe body (1), wherein the gap between the outer surface of the valve body (2) and the inner wall of the balance pipe body (1) forms the flow passage of the balance pipe of the hydraulic turbine; the valve body (2) is a spindle-like streamlined valve body, and the maximum diameter of the valve body (2) is smaller than the minimum diameter of the variable diameter section of the balance pipe body (1); an adjusting mechanism (3) connected to the valve body (2) and adapted to push the valve body (2) to move in the variable diameter section so as to change the flow area of the flow passage of the balance pipe of the hydraulic turbine; the balance pipe body (1) comprises: a first straight pipe (11) having a first end connected to the draft tube of the hydraulic turbine through a sealing flange and a first end in a conical cylinder structure to form the variable diameter section; an elbow pipe (12) having a first end connected to the second end of the first straight pipe (11) through a sealing flange, wherein the adjusting mechanism (3) is arranged in the elbow pipe (12) and faces the first straight pipe (11); a second straight pipe (13) having a first end connected to the second end of the elbow pipe (12) through a sealing flange and a second end connected to the upper crown gap cavity of the hydraulic turbine through a sealing flange.

2. The hydraulic turbine balance pipe of claim 1, wherein The maximum diameter of the valve body (2) satisfies: wherein Dmax represents the maximum diameter of the valve body, Dmax represents the maximum diameter of the variable diameter section of the balance pipe body, Dmax represents the inclined length of the variable diameter section of the balance pipe body, Dmax represents the inclined angle of the variable diameter section of the balance pipe body.

3. The hydraulic turbine balance pipe of claim 1, wherein the adjusting mechanism (3) comprises: a connecting seat (31) fixed to the elbow pipe (12), wherein a connecting channel coaxial with the axis of the first straight pipe (11) is formed in the connecting seat (31) and connected to the elbow pipe (12); a connecting rod (32) arranged in the connecting channel of the connecting seat (31) and the elbow pipe (12), wherein the first end of the connecting rod (32) is connected to the valve body (2); a driving device (33) connected to the second end of the connecting rod (32) and adapted to drive the connecting rod (32) to move along the axis of the first straight pipe (11) so as to adjust the position of the valve body (2) in the first straight pipe (11).

4. The hydraulic turbine balance pipe of claim 3, wherein the connecting seat (31) comprises: a connecting sleeve (311) having a first end welded to the elbow pipe (12) and a second end provided with a stepped hole, wherein the connecting sleeve (311) is coaxial with the first straight pipe (11); a connecting end cover (312) detachably connected to the stepped hole of the second end of the connecting sleeve (311), wherein a through hole is arranged in the center of the connecting end cover (312) and adapted to sequentially pass through the connecting rod (32), the connecting sleeve (311) and the elbow pipe (12); a sealing element (313) arranged in the gap between the connecting rod (32) and the connecting sleeve (311). A sealing filler (314) is filled between the connecting end cover (312) and the stepped hole of the second end of the connecting sleeve (311).

5. A method of regulating the flow of a hydraulic turbine balance pipe, characterized by, The water turbine balance pipe flow adjusting method is suitable for adjusting the water turbine balance pipe according to any one of claims 1 to 4. The fluid flow in the main flow channel, the upper crown cavity, the lower ring cavity, the leakage prevention ring and the balance pipe of the water turbine is simulated by using a water turbine fluid flow numerical simulation method, and different working points of the water turbine are simulated. In the simulation of the first working point of the water turbine, the position of the valve body (2) in the variable diameter section of the balance pipe body (1) is changed by the adjusting mechanism (3) to change the flow area of the balance pipe body (1), the corresponding runner axial force and the leakage between the runner and the stationary part of the balance pipe body (1) under different flow areas are obtained, a test set is formed, and the position of the valve body (2) corresponding to the runner axial force and the leakage between the runner and the stationary part of the water turbine under the optimal condition is obtained by using an optimization algorithm based on the test set. The simulation working point of the water turbine is changed, the position of the valve body (2) in the variable diameter section of the balance pipe body (1) is changed again by the adjusting mechanism (3), and the position of the valve body (2) corresponding to the runner axial force and the leakage between the runner and the stationary part of the water turbine under the optimal condition is obtained. The position of the valve body (2) corresponding to the runner axial force and the leakage between the runner and the stationary part of the water turbine under the optimal condition is integrated to form a data set. In the actual operation of the water turbine, the position of the valve body (2) in the variable diameter section of the balance pipe body (1) is adjusted based on the data set to change the flow area of the balance pipe body (1), so that the runner axial force and the leakage between the runner and the stationary part of the water turbine remain in the optimal state.

6. The method of Francis turbine balancing pipe flow regulation according to claim 5, characterized in that, In the actual operation of the water turbine, the position of the valve body (2) in the variable diameter section of the balance pipe body (1) is adjusted based on the data set, and an automatic control process is adopted, which includes: The data set is stored in the form of a data table in the water turbine power station control system. The water turbine power station control system automatically controls the position of the valve body (2) by the adjusting mechanism (3) based on the data set to match the actual operation condition of the water turbine.

7. The method of claim 5, wherein, In the actual operation of the water turbine, the position of the valve body (2) in the variable diameter section of the balance pipe body (1) is adjusted based on the data set, and a manual control process is adopted, which includes: The data set is classified according to the working condition range of the water turbine, and a plurality of adjustment level indication keys are formed on the adjusting mechanism (3), different adjustment level indication keys correspond to different working conditions of the water turbine; Based on the actual operation condition of the water turbine, the corresponding adjustment level indication key is manually adjusted on the adjusting mechanism (3) to match the actual operation condition of the water turbine.

8. A hydraulic turbine characterized by The water turbine balance pipe or the water turbine balance pipe flow adjusting method can be executed.

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