Three-chamber water chamber type surge tank structure and hydraulic design method thereof

Abstract

The application discloses a three-chamber water chamber type surge chamber structure and a hydraulic design method thereof, and belongs to the technical field of water conservancy and hydropower facilities. The three-chamber water chamber type surge chamber structure comprises a vertical shaft, the lateral wall of the upper end of the vertical shaft is connected with a chamber structure, the chamber structure comprises an upper chamber, a middle chamber and a lower chamber, the upper chamber, the middle chamber and the lower chamber are sequentially and vertically connected on one side of the lateral wall of the vertical shaft, the upper chamber, the middle chamber and the lower chamber are gradually changed structures respectively, and the lower end of the vertical shaft is connected with a communication pipe for connecting a water diversion tunnel. Through the arrangement of the upper chamber, the middle chamber and the lower chamber, the maximum surge amplitude can be effectively suppressed, and the convergence of water level fluctuation is accelerated, and meanwhile, the hydraulic characteristics and the structural characteristics are good, so that the stable operation of the water diversion system is ensured, and especially in the long-distance, large-flow and high-head water diversion system, the design requirements of the surge chamber can be met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water conservancy and hydropower facilities, and particularly relates to a three-chamber water chamber type surge chamber structure and a hydraulic design method thereof. BACKGROUND

[0002] In the process of achieving the "double carbon" goal, new energy represented by solar energy and wind energy has become an inevitable trend in future development, but due to the random and fluctuating characteristics of solar energy and wind energy, the development and utilization of water energy resources play an important role in the field of future new energy;

[0003] Water diversion projects, hydropower stations, pumped storage power stations and other fields are related to water diversion systems. Due to the influence of unstable factors or transient characteristics, the pipeline of the water diversion system will have varying degrees of pressure and flow changes, resulting in the propagation of water hammer waves and leading to unstable operation of the system. The reasonable size selection and size design of the surge chamber, as an important pressure regulating building of the water diversion system of the water conservancy project, are crucial to the stable operation of the water diversion system.

[0004] In view of the characteristics of different water diversion systems, some different forms of surge chambers are designed and developed in engineering. Patent CN104110016A discloses a new piston energy dissipation type surge chamber, which has the characteristics of a simple surge chamber and an impedance surge chamber. Patent CN110219288A proposes a double impedance type surge chamber, two connecting pipes are arranged between the pressure pipeline and the surge chamber to realize local energy loss. Patent CN118224543A proposes a combined air cushion surge chamber, which includes a inclined shaft extension pipeline and an air cushion surge chamber, etc., which can reduce the volume of the air cushion surge chamber. Patent CN201473934U relates to a split pier type differential surge chamber, which can improve the stress distribution at the bottom plate of the surge chamber. Patent CN201738288U proposes a symmetrically arranged double-chamber type surge chamber structure, the lower chamber and the upper chamber are symmetrically distributed on both sides of the vertical shaft. Patent CN117230762A sets two chambers at the same horizontal height, and the two chambers are connected with the main pipe through the communication pipe to form a new double-chamber type surge chamber. The optimization design method of the above-mentioned surge chamber is suitable for low water head water diversion system, but with the development of long-distance, large-flow and super-high water head water diversion system, the design and optimization method of the existing surge chamber has gradually failed to meet the needs of actual engineering. Therefore, it is urgent to propose a three-chamber water chamber type surge chamber structure and a hydraulic design method thereof. SUMMARY

[0005] The purpose of the present application is to provide a three-chamber water chamber type surge chamber structure and a hydraulic design method thereof to solve the problems in the prior art.

[0006] To achieve the above object, the technical scheme adopted by the application is as follows: a three-chamber water chamber type surge chamber structure, comprising a shaft, a side wall of an upper end of the shaft being connected with a chamber structure, the chamber structure comprising an upper chamber, a middle chamber and a lower chamber, the upper chamber, the middle chamber and the lower chamber being connected in sequence vertically on one side of the side wall of the shaft, the upper chamber, the middle chamber and the lower chamber each being a gradual change structure, and the size of an inlet end of the upper chamber, the middle chamber and the lower chamber being larger than that of a tail end, and a communication pipe for connecting a water diversion tunnel being connected to a lower end of the shaft.

[0007] By adopting the above technical scheme, the water hammer pressure of the water diversion system is adjusted by the connection of the shaft with the upper chamber, the middle chamber and the lower chamber, and the water level fluctuation in the surge chamber is effectively inhibited, and the gradual change structure design can effectively exhaust the chamber during the submerging process and make the flow more smooth, thereby reducing the energy loss in the unstable gas-liquid two-phase flow process.

[0008] Optionally, the cross sections of the upper chamber, the middle chamber and the lower chamber are each door-hollow-shaped, the upper parts of the cross sections of the upper chamber, the middle chamber and the lower chamber are each semicircular structure, the lower parts are rectangular structure, the areas of the rectangular structures of the upper chamber, the middle chamber and the lower chamber from the inlet end are sequentially reduced, and the radii of the semicircular structures of the upper chamber, the middle chamber and the lower chamber from the inlet end to the tail end are unchanged.

[0009] By adopting the above technical scheme, the cross section is designed as door-hollow-shaped, the upper part is semicircular structure, the lower part is rectangular structure, the areas of the rectangular structures from the inlet end to the tail end are sequentially reduced, and the radii of the semicircular structures are unchanged, which makes the chamber more in line with the principle of fluid mechanics, is conducive to the stable flow of fluid, and is conducive to the overall stability and deformation resistance of the structure.

[0010] Optionally, the cross-sectional area of the shaft is calculated according to the Tomah critical cross-sectional area formula, and the cross-sectional area of the shaft is satisfying the following relationship: , wherein K is a coefficient, and ; is the Tomah critical cross-sectional area.

[0011] By adopting the above technical scheme, the cross-sectional area of the shaft is calculated according to the Tomah critical cross-sectional area formula, which ensures the rationality of the hydraulic design of the shaft, and this step is the basis of the design and is crucial for the subsequent design work.

[0012] Optionally, the area of the cross section of the water diversion tunnel is , the area of the cross section of the communication pipe is , satisfying the following relationship: , and the area of the cross section of the communication pipe The cross-sectional area of ​​the shaft Satisfies the following relationship, < .

[0013] By adopting the above technical solution, the cross-sectional area of ​​the connecting pipe is calculated based on the cross-sectional area of ​​the water diversion tunnel, ensuring that the connecting pipe can effectively suppress large water level fluctuations and accelerate the convergence speed of the fluctuations.

[0014] Optionally, the lengths of the rectangular structures at the inlet ends of the upper chamber, the middle chamber, and the lower chamber are respectively a and b, and the radii of the semicircular structures of the upper chamber, the middle chamber, and the lower chamber are respectively The lengths of the upper chamber, the middle chamber and the lower chamber are L, and the slopes of the top and bottom plates of the upper chamber, the middle chamber and the lower chamber are and , and 0< <2% and <2%, then the height of the rectangular structure of the upper chamber, the middle chamber and the tail end of the lower chamber is , respectively satisfying the following relations: .

[0015] By adopting the above technical solution, the design of the chamber size takes into account multiple factors such as the area of ​​the rectangular structure, the radius of the semicircular structure, the chamber length, and the slope of the top and bottom plates. These design parameters jointly determine the hydraulic characteristics of the chamber, ensuring that the water flow can maintain a stable flow state when passing through each chamber.

[0016] Optionally, the length of the connecting pipe is , the elevation of the bottom of the connecting pipe is , the water level of the reservoir is The height from the bottom plate of the upper chamber inlet to the upper surface of the diversion tunnel is The height from the horizontal plane in the upper chamber to the bottom plate of the upper chamber is the upper chamber submergence depth. , then the upper chamber submergence depth The following relationship is satisfied: , , where is the height of the rectangular structure at the inlet end of the upper chamber, and R is the radius of the semicircular structure at the inlet end of the upper chamber.

[0017] By adopting the above technical solution, it is possible to ensure that the upper chamber plays the best regulating role in the surge chamber structure while maintaining the stability and reliability of the structure. By reasonably designing this depth, it is possible to ensure that the upper chamber can maintain a stable operating state while avoiding the adverse effects of excessively high or low water levels on the structure.

[0018] Optionally, the water head loss of the entire unit rated operating condition steady state is , the height from the bottom plate of the lower chamber inlet end to the upper surface of the water diversion tunnel is , the height from the horizontal surface in the lower chamber to the bottom plate of the lower chamber is the lower chamber submergence depth , and the lower chamber submergence depth satisfies the following relationship: , , wherein is the height of the rectangular structure of the lower chamber inlet end, and R is the radius of the semicircular structure of the lower chamber inlet end.

[0019] By adopting the technical scheme, the position of the lower chamber is reasonably set, so that the lower chamber can play the best regulating role in the pressure regulating process, and the stability and reliability of the structure are maintained.

[0020] Optionally, the vertical height between the top plate of the middle chamber and the bottom plate of the upper chamber is , the vertical height between the bottom plate of the middle chamber and the top plate of the lower chamber is , and .

[0021] By adopting the technical scheme, the middle chamber is located between the upper chamber and the lower chamber, stores excess water during load rejection, and assists the lower chamber to supplement more water during load increase, so as to improve the water hammer pressure of the water diversion system and reduce the water level fluctuation in the surge chamber.

[0022] Optionally, after the structure of the surge chamber is designed, the hydraulic characteristics of the surge chamber structure are verified by a one-dimensional numerical calculation method.

[0023] By adopting the technical scheme, the hydraulic characteristics of the surge chamber structure are verified by a one-dimensional numerical calculation method, so that the problems in the design can be found and corrected in time, the performance of the structure is ensured to meet the requirements, and this step is an important link in the design process and is crucial for ensuring the accuracy and reliability of the final design.

[0024] Optionally, a hydraulic design method of a three-chamber surge chamber structure includes the following steps:

[0025] The cross-sectional area F of the vertical shaft is determined;

[0026] The size of the communicating pipe is calculated;

[0027] The sizes of the upper chamber, the middle chamber and the lower chamber are designed;

[0028] Determine the position of the upper chamber, the middle chamber and the lower chamber;

[0029] Design a new surge chamber structure through the cross-sectional area of the shaft, the size of the communication pipe, the upper chamber, the middle chamber and the lower chamber, and the position of the upper chamber, the middle chamber and the lower chamber, and verify the hydraulic characteristics of the new surge chamber structure.

[0030] By adopting the technical scheme, the rationality and reliability of the surge chamber structure are ensured through a series of steps, each step is calculated and considered, and the accuracy and practicability of the final design are ensured.

[0031] Compared with the prior art, the beneficial effects of the present application are:

[0032] 1. In a long-distance, large-flow and high-head water diversion system, the present application increases the upper chamber, the middle chamber and the lower chamber, fully utilizes the space in the horizontal direction, and makes the three-chamber water chamber type surge chamber structure have higher applicability and stability compared with the conventional impedance type surge chamber and the simple surge chamber under the same vertical height; this design can more effectively regulate water hammer pressure and ensure the stable operation of the water diversion system.

[0033] 2. Compared with three single surge chambers, the upper chamber, the middle chamber and the lower chamber are arranged vertically in sequence, and are directly connected with the shaft, the three-chamber water chamber type surge chamber structure increases the middle chamber, can store excess water when the surge chamber structure sheds load, can effectively suppress the maximum surge amplitude, and is beneficial to accelerate the convergence of water level fluctuation; when the surge chamber structure increases load, it can assist the lower chamber to supplement more water to suppress the water level fluctuation in the surge chamber structure and reduce the fluctuation period.

[0034] 3. The design of the gradual change structure can make the fluid flow more smoothly in the chamber, thereby reducing the energy loss in the unstable gas-liquid two-phase flow process, and the door-shaped design can effectively disperse and withstand the pressure from the rock mass, and compared with the square chamber, the structure is more stable, and the door-shaped design can be applied to various geological conditions; the gradual change structure cooperates with the door-shaped design to optimize fluid flow, enhance structural stability and improve surge effect.

[0035] 4. The present application reasonably designs the size, position and cross-sectional area of the communication pipe of each chamber and other parameters, so that the surge chamber can better adapt to the change of water flow under different working conditions, and improves the stability and reliability of the surge chamber. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a whole structure schematic diagram of the surge chamber structure of the present application;

[0037] Figure 2 It is the main view structure schematic diagram of the pressure regulating chamber structure of the present application.

[0038] Figure 3 It is the main view structure schematic diagram of the pressure regulating chamber structure of the present application. Figure 2 It is the enlarged structure schematic diagram of A in the present application.

[0039] Figure 4 It is the partial structure schematic diagram of the pressure regulating chamber structure of the present application.

[0040] Figure 5 It is the inlet end cross section structure schematic diagram of the chamber structure of the present application.

[0041] Figure 6 It is the comparison schematic diagram of the hydraulic characteristics of load shedding and load increasing of the present application.

[0042] Figure 7 It is the comparison schematic diagram of the hydraulic characteristics of the double chamber type pressure regulating chamber and the three chamber type pressure regulating chamber of the present application.

[0043] In the figure: 1, shaft; 2, chamber structure; 21, upper chamber; 22, middle chamber; 23, lower chamber; 3, communication pipe; 4, diversion tunnel; 5, pressure pipeline. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0045] In the description of the present application, it should be noted that the directions or position relations indicated by the terms “middle”, “upper”, “lower”, “left”, “right”, “inner”, “outer” and the like are the directions or position relations shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0046] As Figure 1The specific scheme of the embodiment is shown in Figure 5, and is as follows: a three-chamber water chamber type surge tank structure, comprising a shaft 1 serving as a support and core part of the entire surge tank structure and used to connect three horizontal chambers, a chamber structure 2 being connected to the side wall of the upper end of the shaft 1, the chamber structure 2 comprising an upper chamber 21, a middle chamber 22 and a lower chamber 23, the upper chamber 21, the middle chamber 22 and the lower chamber 23 being connected in sequence and vertically on one side of the side wall of the shaft 1, the upper chamber 21, the middle chamber 22 and the lower chamber 23 each being a gradual change structure, and the size of the inlet end of the upper chamber 21, the middle chamber 22 and the lower chamber 23 being greater than that of the tail end.

[0047] The cross sections of the upper chamber 21, the middle chamber 22 and the lower chamber 23 are each door hole-shaped, the upper part of the cross section of each of the upper chamber 21, the middle chamber 22 and the lower chamber 23 being a semicircular structure, and the lower part being a rectangular structure, the area of the rectangular structure of the upper chamber 21, the middle chamber 22 and the lower chamber 23 gradually decreasing from the inlet end to the tail end, and the radius of the semicircular structure of the upper chamber 21, the middle chamber 22 and the lower chamber 23 being constant from the inlet end to the tail end, the design of the gradual change structure ensuring smooth exhaust of each chamber during the water level rising process and preventing the generation of harmful gas, the lower end of the shaft 1 being connected with a communication pipe 3 used to connect a water diversion tunnel 4, the communication pipe 3 serving as a key component for connecting the shaft 1 and the water diversion tunnel 4, the communication pipe 3 being connected vertically to the surface of the water diversion tunnel 4, and one end of the water diversion tunnel 4 close to the communication pipe 3 being connected with a pressure conduit 5.

[0048] A hydraulic design method of a three-chamber water chamber type surge tank structure comprises the following steps:

[0049] determining the cross-sectional area F of the shaft 1;

[0050] The cross-sectional area of the shaft 1 is calculated according to the Tomah critical cross-sectional area formula, and the cross-sectional area of the shaft 1 is satisfying the following relationship: , wherein K is a coefficient, and ; is the Tomah critical cross-sectional area; by determining the size of the shaft 1, a reliable support foundation is provided for the subsequent chamber design.

[0051] calculating the size of the communication pipe 3;

[0052] the cross-sectional area of the water diversion tunnel 4 being , the cross-sectional area of the communication pipe 3 being , satisfying the following relationship: ; and the cross-sectional area of the communication pipe 3 being and the cross-sectional area of the shaft 1 being satisfy the following relationship, < ; through reasonable design of the connecting pipe 3, the connecting pipe 3 can play a role of impedance hole, effectively suppress water level fluctuation in the surge chamber structure, accelerate the convergence speed of fluctuation, thereby ensuring stable operation of the whole system.

[0053] designing sizes of the upper chamber 21, the middle chamber 22 and the lower chamber 23;

[0054] a length of a rectangular structure of an inlet end of the upper chamber 21, the middle chamber 22 and the lower chamber 23 is a, a height thereof is b, a cross section radius of a semi-circular structure of the upper chamber 21, the middle chamber 22 and the lower chamber 23 is , a length of the upper chamber 21, the middle chamber 22 and the lower chamber 23 is L, and a slope of a top plate and a bottom plate of the upper chamber 21, the middle chamber 22 and the lower chamber 23 is and , and 0 <2% and <2%, a height of the rectangular structure of the upper chamber 21, the middle chamber 22 and the lower chamber 23 is respectively satisfy the following relationship: ; the size design of the upper chamber 21, the middle chamber 22 and the lower chamber 23 considers smooth discharge of gas in the water level rising process, avoids formation of harmful gas, and the size design of the chambers further considers stability of the structure and smoothness of water flow.

[0055] determining positions of the upper chamber 21, the middle chamber 22 and the lower chamber 23;

[0056] the position of the upper chamber 21 is determined by the reservoir water level, the water level in the surge chamber is flush with the reservoir water level after the unit is stopped, the reservoir water level is ensured to be slightly higher than a height of a bottom plate of the upper chamber 21, the length of the connecting pipe 3 is , an elevation of a bottom of the connecting pipe 3 is , the water level of the reservoir is , a height from a bottom plate of an inlet end of the upper chamber 21 to an upper surface of the diversion tunnel 4 is , a height from a horizontal surface in the upper chamber 21 to the bottom plate of the upper chamber 21 is a submergence depth of the upper chamber 21 , the submergence depth of the upper chamber 21 is satisfies the following relationship: , , wherein H is the height of the rectangular structure of the inlet end of the upper chamber 21, and R is the radius of the semicircular structure of the inlet end of the upper chamber 21. The height of the upper chamber 21 is required to be not less than 1 m higher than the highest surge water level. The design of the upper chamber 21 can ensure that the upper chamber 21 plays the best regulating role in the surge chamber structure and maintains the stability and reliability of the structure.

[0057] The position of the lower chamber 23 is determined by the water level of the reservoir and the water head loss in the rated steady state operation of all the units. The water level in the lower chamber 23 is required to be slightly higher than the height of the bottom plate of the lower chamber 23. Assuming that the water head loss in the rated steady state operation of all the units is , the height from the bottom plate of the inlet end of the lower chamber 23 to the upper surface of the diversion tunnel 4 is , and the height from the horizontal surface in the lower chamber 23 to the bottom plate of the lower chamber 23 is the submergence depth of the lower chamber 23 , then the submergence depth of the lower chamber 23 is The following relationship is met: , wherein H is the height of the rectangular structure of the inlet end of the lower chamber 23, and R is the radius of the semicircular structure of the inlet end of the lower chamber 23. The bottom of the lower chamber 23 is required to be lower than the lowest surge water level. The position of the lower chamber 23 is reasonably set to ensure that the lower chamber 23 can play the best regulating role in the surge process and maintain the stability and reliability of the structure.

[0058] The middle chamber 22 is located between the upper chamber 21 and the lower chamber 23. Assuming that the height between the top plate of the middle chamber 22 and the bottom plate of the upper chamber 21 is , and the height between the bottom plate of the middle chamber 22 and the top plate of the lower chamber 23 is , then The middle chamber 22 is located between the upper chamber 21 and the lower chamber 23. When the load is shed, the middle chamber 22 stores excess water. When the load is increased, the middle chamber 22 assists the lower chamber 23 to supplement more water, so as to improve the water hammer pressure of the diversion system and reduce the water level fluctuation in the surge chamber.

[0059] The height of the vertical shaft 1 is The height of the top of the vertical shaft 1 should be not less than 1 m higher than the top plate of the inlet end of the upper chamber 21. The height of the communication pipe 3 is , and the total height of the surge chamber structure is .

[0060] A new surge chamber structure is designed through the size and position of the vertical shaft 1, the size and position of the communication pipe 3, the size of the upper chamber 21, the middle chamber 22 and the lower chamber 23, and the hydraulic characteristics of the new surge chamber structure are verified.​

[0061] After the new surge chamber structure design is completed, the hydraulic characteristics of the new surge chamber structure are verified through one-dimensional numerical calculation, so that problems in the design can be found and corrected in time to ensure that the performance of the structure meets the requirements. Parameter optimization design can further improve the stability and efficiency of the structure, so that it can maintain the best working state under various working conditions.

[0062] In Example Two, taking the upstream water diversion system of a certain power station as an example, the water diversion flow is 98.8 m³ / s, and the unit installation elevation is taken as the reference elevation. The water level of the reservoir is 750 m, the elevation of the bottom of the communication pipe 3 on the surge chamber structure is 600 m, the length of the water diversion tunnel 4 is 28 km, the diameter of the water diversion tunnel 4 is 6 m, the length of the pressure pipeline 5 is 1 km, the diameter of the pressure pipeline 5 is 5 m, the height of the shaft 1 is 161 m, the height of the communication pipe 3 is 3 m, the total height of the surge chamber structure is 164 m, and the length of the communication pipe 3 is 3 m.

[0063] (1) Determine the cross-sectional area F of the shaft 1.

[0064] The cross-sectional area of the shaft 1 is calculated according to the Tomah critical cross-sectional area formula, and the Tomah critical cross-sectional area is 17.85 m². Therefore, the cross-sectional area of the shaft 1 is 71.4 m², which satisfies the following relationship: , where K is 4. Calculation shows that the cross-sectional area of the shaft 1 is 71.4 m², and the diameter of the shaft 1 is 9.535 m through conversion. In order to meet the design requirements, the diameter of the shaft 1 is rounded to 10 m, and the stable cross-sectional area of the shaft 1 is 78.54 m² through conversion.

[0065] (2) Calculate the size of the communication pipe 3.

[0066] The cross-sectional area of the water diversion tunnel 4 is 28.27 m², and the cross-sectional area of the communication pipe 3 is 12.72 m², which satisfies the following relationship: , where the value is 45%. Calculation shows that the cross-sectional area of the communication pipe 3 is 12.72 m², and the length of the communication pipe 3 is 3 m.

[0067] (3) Design the size of the upper chamber 21, the middle chamber 22, and the lower chamber 23.​​​​​​​​​​​​​​

[0068] The length a = 8m, the height b = 10m of the upper chamber 21, the middle chamber 22 and the lower chamber 23 entrance end rectangular structure, the radius of the upper chamber 21, the middle chamber 22 and the lower chamber 23 half circle structure 4m, the length L = 240 of the upper chamber 21, the middle chamber 22 and the lower chamber 23, the slope of the top plate and the bottom plate of the upper chamber 21, the middle chamber 22 and the lower chamber 23 1.5% and 1%, and 0 <2% and <2%, the height of the tail end rectangular structure of the upper chamber 21, the middle chamber 22 and the lower chamber 23 is respectively satisfy the following relationship: = 10-240x0.015-240x0.01 = 4m.

[0069] (4) determine the position of the upper chamber 21, the middle chamber 22 and the lower chamber 23;

[0070] The position of the upper chamber 21 is determined by the reservoir water level = 750m, the water level in the surge chamber is flush with the reservoir water level after the unit is shut down, and the reservoir water level is slightly higher than the height of the bottom plate of the upper chamber 21, the height of the bottom plate of the upper chamber 21 entrance end to the upper surface of the diversion tunnel 4 = 149m, the height of the horizontal surface in the upper chamber 21 to the bottom plate of the upper chamber 21 is the submergence depth of the upper chamber 21 , and the submergence depth of the upper chamber 21 is less than 4.67m, so the submergence depth of the upper chamber 21 = 750-600-149 = 1m, the height of the upper chamber 21 should ensure that the safety height above the highest surge water level is not less than 1m, and the design of the upper chamber 21 can ensure that the upper chamber 21 plays the best regulating role in the surge chamber structure, while maintaining the stability and reliability of the structure.

[0071] The position of the lower chamber 23 is determined by the reservoir water level = 750m and the head loss = 37.8m under the rated operating condition of all units, which ensures that the water level in the lower chamber 23 is slightly higher than the height of the bottom plate of the lower chamber 23, the height of the bottom plate of the lower chamber 23 entrance end to the upper surface of the diversion tunnel 4 = 108m, the height of the horizontal surface in the lower chamber 23 to the bottom plate of the lower chamber 23 is the submergence depth of the lower chamber 23 , and the submergence depth of the lower chamber 23 Lower than 4.67 m, so the sub-chamber 23 is submerged = 750 - 600 - 37.8 - 108 = 4.2 m, the bottom of the sub-chamber 23 is lower than the lowest surge water level. The position of the sub-chamber 23 is reasonably set to ensure that the sub-chamber 23 can play the best regulating role in the pressure regulating process, while maintaining the stability and reliability of the structure.

[0072] The middle chamber 22 is located between the upper chamber 21 and the sub-chamber 23, the height between the top plate of the middle chamber 22 and the bottom plate of the upper chamber 21 is = 5 m, the height between the bottom plate of the middle chamber 22 and the top plate of the sub-chamber 23 is = 8 m, .

[0073] The height of the shaft 1 is , the height of the top of the shaft 1 should be higher than the top plate of the inlet of the upper chamber 21 by not less than 1 m, which is 1 m in this embodiment, so = 161 m; the height of the communication pipe 3 is = 3 m, the total height of the pressure regulating chamber structure is = 164 m.

[0074] (5) Design a new pressure regulating chamber structure by the cross-sectional area F of the shaft 1, the cross-sectional area S of the communication pipe 3, the size of the upper chamber 21, the middle chamber 22 and the sub-chamber 23, the position of the upper chamber 21, the middle chamber 22 and the sub-chamber 23, and verify the hydraulic characteristics of the new pressure regulating chamber structure;

[0075] After the new pressure regulating chamber structure is designed, the one-dimensional numerical calculation method is used to verify the hydraulic characteristics of the new body, the hydraulic characteristics of the pressure regulating chamber body under load rejection and load increase are calculated, and the calculation results are shown in Figure 6 .

[0076] As can be seen from Figure 6 , under the unit load rejection condition, due to the horizontal cross-sectional area of each chamber being much larger than the cross-sectional area of the shaft 1, the water level is affected by the upper chamber 21, the middle chamber 22 and the sub-chamber 23, and the water level presents a stepped type rising, and the water level waveform in each chamber area is relatively horizontal, the surge amplitude of the three-chamber pressure regulating chamber is 158.2 m, and with the passage of time, the water level fluctuation in the pressure regulating chamber gradually tends to be flat, under the load increase condition, the water level of the three-chamber pressure regulating chamber presents a stepped type descending, the water level of the pressure regulating chamber reaches stable at a relatively fast speed, and there is no obvious oscillation phenomenon in the process, so the three-chamber water chamber type pressure regulating chamber structure designed in this example has good effect in suppressing water level fluctuation, and can be considered to have good hydraulic characteristics and reasonable design.

[0077] As can be seen fromFigure 7 It can be known that the structure and layout of the double-chamber pressure regulating chamber in the figure are the same as those of the three-chamber pressure regulating chamber, and the cavity structures of both are gradient structures, and the only difference is that the double-chamber pressure regulating chamber has no middle chamber. The surge amplitude fluctuation line of the double-chamber pressure regulating chamber is obtained through calculation. It is obtained through the fluctuation line that the surge amplitude of the double-chamber pressure regulating chamber fluctuates greatly up and down, while the surge amplitude of the three-chamber pressure regulating chamber fluctuates slowly up and down. The surge amplitude fluctuation line of the double-chamber pressure regulating chamber is compared and analyzed with the surge amplitude fluctuation line of the three-chamber pressure regulating chamber. The three-chamber pressure regulating chamber is better than the double-chamber pressure regulating chamber in suppressing the maximum surge amplitude.

[0078] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A three-chambered surge chamber structure of the water chamber type, characterized in that, The application relates to a vertical shaft, the side wall of the upper end of which is connected with a chamber structure, the chamber structure comprising an upper chamber, a middle chamber and a lower chamber, which are connected in sequence on one side of the side wall of the vertical shaft, the upper chamber, the middle chamber and the lower chamber are gradually changed in structure, the size of the inlet end of the upper chamber, the middle chamber and the lower chamber is larger than that of the tail end, the cross section of the upper chamber, the middle chamber and the lower chamber is door hole-shaped, the upper part of the cross section of the upper chamber, the middle chamber and the lower chamber is semicircular structure, and the lower part is rectangular structure, the area of the rectangular structure of the upper chamber, the middle chamber and the lower chamber from the inlet end to the tail end is gradually reduced, the radius of the semicircular structure of the upper chamber, the middle chamber and the lower chamber from the inlet end to the tail end is unchanged, and the lower end of the vertical shaft is connected with a communication pipe for connecting a water diversion tunnel.

2. A three-chambered plenum chamber pressure regulating chamber structure according to claim 1, characterized in that: The cross-sectional area of the shaft is calculated according to the Tommer critical cross-sectional area formula, and the cross-sectional area of the shaft satisfies the following relationship: , wherein K is a coefficient, and ; is the Tommer critical cross-sectional area.

3. A three-chambered plenum chamber pressure regulating chamber structure according to claim 1, characterized by: The area of the diversion tunnel section is The area of the communication pipe section is The area of the communication pipe section satisfies the following relationship: The area of the communication pipe section satisfies the following relationship: The area of the communication pipe section satisfies the following relationship, .​​ 4. A three-chambered plenum chamber pressure regulating chamber structure according to claim 1, characterized by: The length of the rectangular structure of the upper chamber, the middle chamber and the lower chamber entrance end is a, the height is b, the radius of the semi-circular structure of the upper chamber, the middle chamber and the lower chamber is , the length of the upper chamber, the middle chamber and the lower chamber is L, the slope of the top plate and the bottom plate of the upper chamber, the middle chamber and the lower chamber is and , and 0< <2% and <2%, the height of the rectangular structure of the upper chamber, the middle chamber and the lower chamber tail end , respectively, satisfy the following relationship: .

5. A three-chambered surge chamber pressure regulating chamber structure according to claim 1, characterized in that The length of the communication pipe is , the elevation of the bottom of the communication pipe is , the water level of the reservoir is , the height from the bottom plate of the inlet end of the upper chamber to the upper surface of the diversion tunnel is , the height from the horizontal surface in the upper chamber to the bottom plate of the upper chamber is the submergence depth of the upper chamber , and the submergence depth of the upper chamber satisfies the following relationship: , , wherein is the height of the rectangular structure of the inlet end of the upper chamber, and R is the radius of the semicircular structure of the inlet end of the upper chamber.

6. A three-chambered surge chamber pressure regulating structure according to claim 1, characterized in that The water head loss of the whole unit in rated working condition and steady state is , the height from the bottom plate of the lower chamber inlet end to the upper surface of the water diversion tunnel is , the height from the horizontal surface in the lower chamber to the bottom plate of the lower chamber is the lower chamber submergence depth , then the lower chamber submergence depth satisfies the following relationship: , , in the formula is the height of the rectangular structure of the lower chamber inlet end, and R is the radius of the semicircular structure of the lower chamber inlet end.

7. A three-chambered surge chamber pressure regulating structure according to claim 1, characterized in that the vertical height between the top plate of the middle chamber and the bottom plate of the upper chamber is the vertical height between the bottom plate of the middle chamber and the top plate of the lower chamber is then .

8. A three-chambered plenum chamber pressure regulating chamber structure according to claim 1, characterized by: After the design of the pressure regulating chamber structure is completed, the hydraulic characteristics of the pressure regulating chamber structure are verified by a one-dimensional numerical calculation method.

9. The hydraulic design method of a three-chamber water chamber type surge tank structure according to claim 1, characterized in that: The hydraulic design method comprises the following steps: determining the cross section area F of the vertical shaft; calculating the shape of the communication pipe; designing the size of the upper chamber, the middle chamber and the lower chamber; determining the position of the upper chamber, the middle chamber and the lower chamber; designing a new pressure regulating chamber structure through the cross section area F of the vertical shaft, the shape of the communication pipe, the size of the upper chamber, the middle chamber and the lower chamber, and the position of the upper chamber, the middle chamber and the lower chamber, and verifying the hydraulic characteristics of the new pressure regulating chamber structure.

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