Runner and hydraulic turbine with adjustable lower ring gap

Abstract

Provided are a runner with adjustable lower ring gap and a hydraulic turbine. The runner with adjustable lower ring gap is applied to the hydraulic turbine and comprises a lower ring. The runner with adjustable lower ring gap further comprises a flow resistance ring system, which comprises a flow resistance ring and a propeller. A bottom of the lower ring forms a flow resistance ring mounting groove, which is an annular groove. The propeller is arranged at a groove bottom of the flow resistance ring mounting groove, and the flow resistance ring is arranged at least partially in the flow resistance ring mounting groove. The propeller is connected to the flow resistance ring and can drive the flow resistance ring to move along the height direction of the flow resistance ring mounting groove, so as to change the size of the gap between the flow resistance ring and the draft tube of the hydraulic turbine.

Description

Technical Field

[0001] This application relates to the field of water turbine technology, and particularly to a runner and water turbine with adjustable lower ring clearance. Background Technology

[0002] The scale of hydropower station construction is constantly increasing, but due to the generally high silt content in rivers, most turbine units suffer from varying degrees of erosion. Silt abrasion of turbines has become a major challenge in hydropower station equipment maintenance. Severe silt abrasion can damage the structural materials of the hydropower equipment itself, affecting operational reliability and stability, leading to reduced turbine efficiency and output. Silt abrasion can also shorten the lifespan of the runner, resulting in shorter overhaul cycles, longer construction periods, and increased demand for materials, consumables, and spare parts, ultimately leading to significant economic losses.

[0003] Because the mechanism of erosion damage is extremely complex and influenced by many factors, research on the protection against this type of damage is a multidisciplinary system engineering project that must be based on practical considerations and adopt comprehensive control measures. Current research on turbine wear resistance focuses primarily on the materials used in turbine manufacturing, aiming to improve the wear resistance of related components. However, using higher-strength wear-resistant materials often significantly increases manufacturing costs and may not completely solve the wear problem of turbine units. Studies have shown that turbine runner wear is mainly caused by unreasonable hydraulic design, which increases the speed and probability of impact between sediment and the turbine wall. Therefore, the most effective and economical anti-wear measure is to optimize the hydraulic design of the turbine runner. Understanding the turbine wear mechanism and optimizing the runner design is of great significance for improving the economic efficiency of turbines and ensuring the safe and stable operation of turbine units.

[0004] CN203067160U discloses a spiral labyrinth seal between the lower ring and lower stop ring of a mixed-flow turbine runner. This structure arranges a rotating spiral sealing groove on the sealing surface of the lower ring of the runner and a fixed spiral sealing groove on the sealing surface of the lower stop ring, which is arranged in the opposite direction to that of the lower ring. The turbulence generated in the spiral labyrinth seal during runner rotation prevents water from entering the downstream area through the gap between the lower ring and the lower stop ring, thus achieving the sealing purpose.

[0005] The spiral labyrinth seal of the lower ring and lower leak-stop ring of the mixed-flow turbine runner disclosed in the above-mentioned utility model improves the sealing structure of the leak-stop ring. However, this structure completely seals the gap between the lower ring and the leak-stop ring, making it impossible for the runner to adjust the gap between the lower ring and the bottom ring, thus limiting the turbine's ability to flexibly adapt to different working environments. Summary of the Invention

[0006] This application is made in view of the aforementioned state of the prior art. The purpose of this application is to provide a wheel with an adjustable lower ring gap, which can adjust the lower ring gap through a flow-blocking ring to control the leakage of the lower ring gap and reduce lower ring wear.

[0007] This application also provides a water turbine including the aforementioned adjustable lower ring gap runner.

[0008] This application provides an adjustable lower ring clearance impeller for use in a water turbine, comprising a lower ring. The impeller with adjustable lower ring clearance further includes a flow-blocking ring system, which includes a flow-blocking ring and a propeller.

[0009] The bottom of the lower ring forms a flow-blocking ring mounting groove, which is an annular groove. The pusher is disposed at the bottom of the flow-blocking ring mounting groove, and the flow-blocking ring is at least partially disposed in the flow-blocking ring mounting groove.

[0010] The propeller is connected to the flow-blocking ring and can drive the flow-blocking ring to move along the height direction of the flow-blocking ring mounting groove, thereby changing the size of the gap between the flow-blocking ring and the tailrace pipe of the turbine.

[0011] In at least one possible implementation, the flow-blocking ring system further includes a gravel ring disposed on the side of the flow-blocking ring away from the propeller.

[0012] In at least one possible implementation, the flow-blocking ring system further includes a controller capable of controlling the operation of the thruster.

[0013] In at least one possible implementation, the flow-blocking ring system further includes a flow meter to monitor gap leakage at the lower ring.

[0014] The flow meter is installed on the outer wall of the lower ring.

[0015] In at least one possible implementation, the flow-restricting ring system further includes a plurality of rollers and / or balls disposed between the flow-restricting ring and the flow-restricting ring mounting groove to facilitate movement of the flow-restricting ring.

[0016] In at least one possible implementation, the diameter of the lower ring is D, and the height of the lower ring is L.

[0017] The depth of the groove for mounting the flow-blocking ring is 0.2L to 0.4L.

[0018] The outer diameter of the choke ring mounting groove is 0.75D to 0.95D, and the inner diameter of the choke ring mounting groove is 0.45D to 0.65D.

[0019] The outer diameter of the flow-blocking ring is 0.7D to 0.9D, and the inner diameter of the flow-blocking ring is 0.5D to 0.7D.

[0020] In at least one possible embodiment, the depth of the choke ring mounting groove is 0.3L, the outer diameter of the choke ring mounting groove is 0.88D, and the inner diameter of the choke ring mounting groove is 0.58D.

[0021] The outer diameter of the flow-blocking ring is 0.8D, and the inner diameter of the flow-blocking ring is 0.6D.

[0022] In at least one possible implementation, the flow-blocking ring can extend to be flush with the upper edge of the tailpipe to completely seal the gap between the lower ring and the tailpipe.

[0023] In at least one possible implementation, the flow-blocking ring is made of stainless steel, the propeller is a hydraulic propeller, and the crushing ring is made of diamond.

[0024] This application also provides a water turbine, which includes:

[0025] Bottom ring and tailrace pipe; and

[0026] The aforementioned adjustable lower ring gap wheel,

[0027] The bottom ring is located radially outside the lower ring.

[0028] The tailwater pipe is located below the lower ring.

[0029] A lower ring gap is formed between the lower ring and the bottom ring, and between the lower ring and the tailwater pipe.

[0030] The adjustable lower ring clearance turbine and impeller provided in this application can adjust the size of the lower ring clearance through the flow-blocking ring, thereby controlling the leakage of the lower ring clearance. This reduces the wear of the lower ring caused by friction and collision between sediment and the lower ring wall, and enhances the wear resistance of the impeller's lower ring. Attached Figure Description

[0031] Figure 1 This is a structural schematic diagram of the axial section of an adjustable lower ring gap wheel according to one embodiment of this application.

[0032] Figure 2 for Figure 1 A magnified view of the lower ring and the flow-blocking ring.

[0033] Figure 3 This is a plan view of the lower ring and the flow-blocking ring according to one embodiment of this application.

[0034] Explanation of reference numerals in the attached figures

[0035] 10 rotor blades

[0036] 20 Top Cover

[0037] 30 crown

[0038] 31 Drain hole

[0039] 40 bottom ring

[0040] 50 Lower ring

[0041] 51. Flow-restricting ring mounting groove

[0042] 60 Drainage Cone

[0043] 70 Flow-blocking ring system

[0044] 71 Flow-blocking ring

[0045] 72 thrusters

[0046] 73 Connecting rod

[0047] 74. Stone Ring

[0048] 75 Roller

[0049] 76 Controller

[0050] 80 tailpipe Detailed Implementation

[0051] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0052] Embodiments of this application provide an adjustable lower ring gap wheel (hereinafter, sometimes simply referred to as "wheel"), such as Figure 1 As shown, the impeller may include impeller blades 10, upper crown 30, lower ring 50, drain cone 60, and flow-blocking ring system 70.

[0053] Specifically, such as Figure 1As shown, the outer surface of the upper crown 30 may include a conical surface (including an approximately conical surface), and multiple impeller blades 10 may be connected to the conical surface of the upper crown 30. The top surface of the upper crown 10 may be connected to the top cover 20 of the turbine. A drain hole 31 may be formed inside the upper crown 30, and a drain cone 60 may be provided at the drain hole 31. The drain cone 60 may be connected to the upper crown 30, and in particular, may be provided at the lower part of the upper crown 30. The outer surfaces of the upper crown 30 and the drain cone 60 may form smooth curved surfaces (in particular conical curved surfaces) to allow water to flow smoothly. The lower ends of the multiple impeller blades 10 may be connected to the inner side of the lower ring 50. A bottom ring 40 of the turbine may be provided on the radially outer side of the lower ring 50, and a gap (lower ring gap) may be formed between the bottom ring 40 and the lower ring 50. A tailpipe 80 can be installed below the lower ring 50, and a gap (lower ring gap) can be formed between the lower ring 50 and the tailpipe 80. The width of the gap between the lower ring 50 and the tailpipe 80 is W. This can be understood as... Figure 1 , Figure 2 As shown, when the turbine is working, the main flow A can flow out of the tailrace pipe 80 through the runner blades 10, and the gap flow B (also known as the lower ring gap flow or gap leakage flow) can flow through the gap between the bottom ring 40 and the lower ring 50 and the gap between the lower ring 50 and the tailrace pipe 80.

[0054] Furthermore, such as Figure 2 , Figure 3 As shown, a choke ring mounting groove 51 can be formed at the bottom of the lower ring 50, with the opening of the choke ring mounting groove 51 facing away from the upper crown 30. It can be understood that the choke ring mounting groove 51 is an annular groove. The choke ring mounting groove 51 can at least partially accommodate the choke ring system 70.

[0055] Specifically, the flow-blocking ring system 70 may include a flow-blocking ring 71 and a propeller 72. The flow-blocking ring 71 and the propeller 72 can be connected by a connecting rod 73, and the propeller 72 can drive the flow-blocking ring 71 to move along the height direction of the flow-blocking ring mounting groove. The propeller 72 can be set at one end of the flow-blocking ring mounting groove 51 near the upper crown 30 (i.e., the bottom of the flow-blocking ring mounting groove 51), and the flow-blocking ring 71 can extend at least partially out of the flow-blocking ring mounting groove 51. It can be understood that the propeller 72 can control the length of the flow-blocking ring 71 extending out of the flow-blocking ring mounting groove 51, that is, it can control the distance from the flow-blocking ring 71 to the tailpipe 80. After the flow-blocking ring 71 extends at least partially out of the flow-blocking ring mounting groove 51, the distance from the bottom of the flow-blocking ring 71 to the upper edge of the tailpipe 80 can be less than the gap width W between the lower ring 50 and the tailpipe 80. At this time, the flow-blocking ring 71 can impede the water flow through the gap between the lower ring 50 and the tailpipe 80, thereby reducing the leakage of the water flow through the gap between the lower ring 50 and the tailpipe 80. The longer the flow-blocking ring 71 extends out of the flow-blocking ring mounting groove 51, the less leakage of the water flow through the gap between the lower ring 50 and the tailpipe 80.

[0056] Let the height of the lower ring 50 be L, and the diameter of the lower ring 50 be D. Preferably, the depth of the baffle ring mounting groove 51 can be 0.2L to 0.4L, the outer diameter of the baffle ring mounting groove 51 can be 0.75D to 0.95D, and the inner diameter can be 0.45D to 0.65D. It can be understood that the outer diameter of the baffle ring mounting groove 51 is larger than the inner diameter. More preferably, the depth of the baffle ring mounting groove 51 can be 0.3L, the outer diameter of the baffle ring mounting groove 51 can be 0.88D, and the inner diameter can be 0.58D.

[0057] Preferably, the outer diameter of the flow-blocking ring 71 can be from 0.7D to 0.9D, and the inner diameter can be from 0.5D to 0.7D. It is understood that the inner diameter of the flow-blocking ring 71 is smaller than its outer diameter, the outer diameter of the flow-blocking ring 71 is smaller than the outer diameter of the flow-blocking ring mounting groove 51, and the inner diameter of the flow-blocking ring 71 is larger than the inner diameter of the flow-blocking ring mounting groove 51. More preferably, the outer diameter of the flow-blocking ring 71 is 0.8D, and the inner diameter is 0.6D.

[0058] Preferably, the flow-blocking ring 71 can be made of stainless steel.

[0059] Preferably, a crushing ring 74 can be provided on the side of the flow-blocking ring 71 away from the propeller 72. The crushing ring 74 can be used to crush stones and other debris in the gap of the lower ring, preventing debris from wearing down the impeller. Specifically, such as Figure 2 As shown, when the flow-blocking ring system 70 does not completely seal the gap between the lower ring 50 and the tailrace pipe 80, that is, when the extension of the flow-blocking ring 71 does not completely block the flow from entering the gap between the lower ring 50 and the tailrace pipe 80, stones and other debris can enter the gap between the lower ring 50 and the tailrace pipe 80 with the flow from the lower ring gap. As the impeller continues to rotate, these stones and other debris may continuously wear down the impeller, especially the lower ring structure. The crushing ring 74 can crush the debris entering the gap between the lower ring 50 and the tailrace pipe 80 while rotating with the impeller, thus avoiding or reducing its wear on the impeller. More preferably, the crushing ring 74 can be made of high-strength diamond.

[0060] Preferably, the thruster 72 can be a hydraulic thruster. The flow-restricting ring system 70 may include a plurality of thrusters 72 disposed in the flow-restricting ring mounting groove 51, for example, such as Figure 3 As shown, the flow-blocking ring system 70 has four propellers 72 evenly arranged around the circumference of the flow-blocking ring mounting groove 51.

[0061] Preferred, such as Figure 2 As shown, multiple rollers 75 can be provided between the flow-blocking ring 71 and the flow-blocking ring mounting groove 51 to facilitate the movement of the flow-blocking ring 71 along the height direction of the flow-blocking ring mounting groove 51. For example, the rollers 75 can be cylindrical rollers, needle rollers, etc. It is understood that the rollers 75 can also be replaced by structures such as ball bearings.

[0062] Preferably, a flow meter (flow sensor or other flow monitoring device) can be installed on the outer wall of the lower ring 50. The flow meter can detect the leakage flow (flow of gap flow B) in the lower ring gap in real time. The operation of the flow-blocking ring system 70 can be controlled in real time based on the gap flow data signal fed back by the flow meter.

[0063] Preferably, the flow-restricting ring system 70 may further include a controller 76, which can control the operation of the propeller 72, thereby adjusting the extension amount of the flow-restricting ring 71. More preferably, the controller 76 may be a wireless intelligent controller.

[0064] It is understandable that the range of extension and retraction of the flow-blocking ring 71 in the flow-blocking ring system 70 can be determined based on the size of the impeller and the gap between the impeller and the tailpipe 80. The maximum adjustable state of the flow-blocking ring 71 (i.e., the maximum extension of the flow-blocking ring 71) can completely seal the gap between the lower ring 50 and the tailpipe 80.

[0065] It is understood that the impeller design provided in this embodiment is based on the principle of hydraulic flow, and the anti-wear effect of the impeller gap can be enhanced by reducing the leakage of the lower ring gap of the impeller.

[0066] It is understood that the impeller provided in this embodiment can also be combined with structures such as a leak-proof ring to better adjust the leakage of the lower ring gap and enhance the wear resistance of the impeller.

[0067] The impeller provided in this embodiment can control the extension length of the flow-blocking ring 71 based on parameters such as the amount of sediment in the working environment and the leakage flow rate in the gap, thereby regulating the size of the gap between the lower ring 50 and the tailrace pipe 80 and the leakage rate of the lower ring gap. When the sediment content exceeds 15 kg / m3 or the unit wear is severe, the flow-blocking ring can be appropriately extended; when the sediment content is less than 15 kg / m3 or the unit wear is relatively minor, the flow-blocking ring can be appropriately contracted. The unit can be extended when operating at low flow rates and contracted when operating at high flow rates. This reduces the wear on the impeller (especially its lower ring) caused by the impact and friction of sediment, stones, etc. carried by the gap flow on the impeller wall, giving the impeller provided in this embodiment better wear resistance.

[0068] An embodiment of this application also provides a water turbine, which includes the aforementioned adjustable lower ring clearance impeller.

[0069] The turbine may also include a top cover 20 disposed above the upper crown 30 of the runner, a tailrace pipe 80 disposed below the runner, and a bottom ring 40 disposed radially outside the runner.

[0070] Preferably, the turbine is a mixed-flow turbine. It is understood that this mixed-flow turbine can be applied to sandy environments. The turbine provided in this application can be used under various head conditions and has broad application prospects in various head conditions ranging from low to high.

[0071] The following is a brief description of some of the beneficial effects of the above-described embodiments of this application.

[0072] The adjustable lower ring gap turbine and water turbine provided in this application have a flow-blocking ring system at the lower ring of the turbine. The leakage rate of the lower ring gap can be adjusted by moving the flow-blocking ring via a propeller. This reduces wear on the lower ring caused by friction and collision between sediment and the lower ring wall, enhancing the wear resistance of the lower ring of the turbine. A crushing ring can also be connected to the bottom of the flow-blocking ring to crush stones and other debris that enter the lower ring gap, further protecting the lower ring and enhancing its wear resistance.

[0073] It is understood that, in this application, when the number of parts or components is not specifically limited, the number can be one or more, where multiple refers to two or more. For cases where the number of parts or components shown in the drawings and / or described in the specification is, for example, two, three, four, etc., this specific number is generally exemplary and not restrictive, and can be understood as multiple, i.e., two or more; however, this does not mean that this application excludes the case of one.

[0074] It should be understood that the above embodiments are merely exemplary and are not intended to limit this application. Those skilled in the art can make various modifications and changes to the above embodiments under the teachings of this application without departing from the scope of this application.

Claims

1. An adjustable lower ring clearance impeller, applied to a water turbine, comprising a lower ring (50), characterized in that, The adjustable lower ring gap wheel also includes a flow-blocking ring system (70), which includes a flow-blocking ring (71) and a propeller (72). The bottom of the lower ring (50) forms a flow-blocking ring mounting groove (51), which is an annular groove. The propeller (72) is disposed at the bottom of the flow-blocking ring mounting groove (51), and the flow-blocking ring (71) is at least partially disposed in the flow-blocking ring mounting groove (51). The propeller (72) is connected to the flow-blocking ring (71) and can drive the flow-blocking ring (71) to move along the height direction of the flow-blocking ring mounting groove (51) to change the size of the gap between the flow-blocking ring (71) and the tailrace pipe (80) of the turbine.

2. The adjustable lower ring gap wheel according to claim 1, characterized in that, The flow-blocking ring system (70) also includes a gravel ring (74), which is disposed on the side of the flow-blocking ring (71) away from the propeller (72).

3. The adjustable lower ring gap wheel according to claim 1, characterized in that, The flow-blocking ring system (70) also includes a controller (76) that can control the operation of the thruster (72).

4. The adjustable lower ring gap wheel according to claim 1, characterized in that, The flow-blocking ring system (70) also includes a flow meter to monitor the gap leakage at the lower ring (50). The flow meter is disposed on the outer wall of the lower ring (50).

5. The adjustable lower ring gap wheel according to claim 1, characterized in that, The flow-blocking ring system (70) also includes a plurality of rollers (75) and / or balls, which are disposed between the flow-blocking ring (71) and the flow-blocking ring mounting groove (51) to facilitate movement of the flow-blocking ring (71).

6. The adjustable lower ring gap wheel according to claim 1, characterized in that, The diameter of the lower ring (50) is D, and the height of the lower ring (50) is L. The groove depth of the flow-blocking ring mounting groove (51) is 0.2L to 0.4L. The outer diameter of the flow-blocking ring mounting groove (51) is 0.75D to 0.95D. The inner diameter of the choke ring mounting groove (51) is 0.45D to 0.65D. The outer diameter of the flow-blocking ring (71) is 0.7D to 0.9D. The inner diameter of the flow-blocking ring (71) is 0.5D to 0.7D.

7. The adjustable lower ring gap wheel according to claim 6, characterized in that, The groove depth of the flow-blocking ring mounting groove (51) is 0.3L. The outer diameter of the choke ring mounting groove (51) is 0.88D. The inner diameter of the flow-blocking ring mounting groove (51) is 0.58D. The outer diameter of the flow-blocking ring (71) is 0.8D. The inner diameter of the flow-blocking ring (71) is 0.6D.

8. The adjustable lower ring gap wheel according to claim 1, characterized in that, The flow-blocking ring (71) can extend to be flush with the upper edge of the tailwater pipe (80) to completely seal the gap between the lower ring (50) and the tailwater pipe (80).

9. The adjustable lower ring gap wheel according to claim 2, characterized in that, The flow-blocking ring (71) is made of stainless steel, the propeller (72) is a hydraulic propeller, and the crushing ring (74) is made of diamond.

10. A water turbine, characterized in that, include: Bottom ring (40) and tailrace pipe (80); as well as The adjustable lower ring gap wheel according to any one of claims 1 to 9, The bottom ring (40) is disposed on the radial outer side of the lower ring (50). The tailwater pipe (80) is located below the lower ring (50). A lower ring gap is formed between the lower ring (50) and the bottom ring (40), and between the lower ring (50) and the tailpipe (80).

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