Anti-corrosion impeller and air-entrainment anti-corrosion impeller set

Abstract

The invention relates to the technical field of impellers, in particular to a corrosion reduction impeller and an air entrainment corrosion reduction impeller set. Comprising a volute, a rotating shaft, a runner, a turntable and multiple blades. And a circulation gap is reserved between the rotating wheel and the rotating disc. The volute wraps the rotating wheel and communicates with the circulation gap. The multiple blades are annularly and evenly distributed in the circulation gap and connected to the rotating wheel and the rotating disc. The rotating shaft is connected to the rotating center of the runner. The rotating shaft is tubular. And channels are formed in the blades and the rotating wheel and are communicated with each other. A channel of the runner communicates with the interior of the rotating shaft. The channel of the blade extends to the surface of the negative pressure area of the blade. The rotating disc is further provided with an opening so that the circulation gap can be communicated with the outside. Air is introduced through the hollow rotating shaft, meanwhile, the air in the rotating shaft is guided to the surfaces of the negative pressure areas of the blades through channels of the rotating wheel and the blades, then the negative pressure in the area of the rotating wheel is balanced, vortexes in the area are scattered, and cavitation and cavitation erosion are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of impellers, and in particular to a cavitation-reducing impeller and an aeration-cavitation-reducing impeller assembly. Background Art

[0002] As my country's energy demand continues to increase, energy storage technology is actively developed on the basis of hydropower development. Pumped storage technology is one of the most widely used and most mature large-scale energy storage methods. Pumped storage power stations have multiple functions such as peak regulation, valley filling, frequency regulation, phase regulation, energy storage, emergency standby and black start. They are an important support for the construction of a new power system of modern smart grids and an important part of building a clean, low-carbon, safe, reliable, smart, flexible, economical and efficient new power system.

[0003] For a mixed flow pump turbine, it usually includes a vertical rotating shaft, a ring-shaped runner is provided at the lower end of the rotating shaft, and the periphery of the runner is provided with a ring-shaped fixed guide vane, movable guide vane and volute. The volute is connected to the upstream water flow, so that a high-pressure mixed flow area is formed inside the annular volute, that is, the runner is located in the mixed flow area, and the lower part of the runner is connected to the low-pressure tailwater pipe, and the tailwater pipe is connected to the water reservoir. When water is released from the upstream, the water flow impacts the blades of the runner through the volute and the guide vane, thereby driving the runner to rotate, which can drive the rotating shaft to rotate, and then drive the generator to generate electricity. After the work is done on the blades, the water flow with a slow flow rate and a low pressure flows into the water reservoir through the tailwater pipe.

[0004] Specifically, under the working condition of a water turbine, the flow in the impeller is similar to that of a mixed flow turbine. The fluid transfers energy to the blades, causing the pressure in the blade channel to gradually decrease from the inlet to the outlet. Therefore, the low-pressure side of the impeller is always located at the inlet of the water pump working condition, that is, the outlet of the water turbine working condition. On the contrary, under the working condition of a water pump, the flow in the impeller is similar to that of a centrifugal pump. Due to the work done by the blades, the pressure in the blade channel gradually increases from the inlet to the outlet. Regardless of the working condition of a water pump or a water turbine, the incoming flow always hits the inlet edge (leading edge) of the blade. After the impact, the flow bypasses the leading edge and separates from the blade surface, causing a sudden drop in the local pressure on the blade surface. At the same time, due to the flow separation, the trailing edge of the blade also experiences a local pressure drop and increase. Therefore, local negative pressure or low pressure will appear to form a negative pressure area, and accordingly, its water flow will form vortices and cavitation. In particular, when the local pressure in the liquid decreases, the vapor or gas originally dissolved in the liquid or on the liquid-solid interface will precipitate to form cavities (cavitation bubbles). When the cavitation bubbles are continuously "generated", "grown", "ruptured" and "generated again", the so-called "cavitation" is formed. At this time, after the metal material is subjected to the impact of cavitation, the surface will be deformed and the material will be eroded, which is called cavitation. Cavitation is an important problem of reversible pump turbines, especially in the pump turbine mode, it usually causes noise, vibration, material damage and operation stability of various water flow components. Cavitation is a hydrodynamic movement with compressible flow characteristics. When the pressure is lower than the saturated vapor pressure, cavitation bubbles will be generated. After the pressure gradually increases, the cavitation bubbles will collapse. When the cavitation bubbles collapse, instantaneous local high temperature (about 5200K) and high pressure (above 50MPa) will be generated, and strong shock waves and micro jets with a speed of more than 100m / s will be formed. The jet will continue to fold into the surface of the unit, and the fatigue resistance of the unit will decrease, causing cavitation.

[0005] In order to effectively solve the above-mentioned cavitation problem, corresponding anti-cavitation structures are usually set up when designing turbines. Specifically, corresponding air supply pipelines are set up to input external air into negative pressure areas such as mixed flow areas for air supply, so as to eliminate the negative pressure of the water flow in the negative pressure area and the formation of vortices.

[0006] However, the existing turbine air supply structure and air supply principle have the following technical defects: First, when the external air or compressed air is input into the mixed flow area and other negative pressure areas for air supply, it is a fixed rhythm of "passive air supply", that is, it is impossible to scientifically and reasonably adjust the air supply amount according to the actual needs of the different operating conditions of the turbine. The consequence is that the air supply is insufficient or even the water flow reverses along the air supply hole due to the low air pressure, which makes the turbine have a safety hazard; or it causes excessive air supply, which not only causes waste, is not conducive to improving efficiency and reducing costs, but also increases bubbles. In the entire mixed flow area, the real negative pressure cavitation area is only a few positions, and the existing technology is difficult to "air entrainment and cavitation reduction" for the real negative pressure cavitation area. In particular, water flow is an almost incompressible fluid, and gas is a compressible fluid. Therefore, using compressible gas to compensate for the negative pressure area and cavitation formed by balancing the incompressible water flow cannot be equivalent to the water flow performance under the pressure balance state. In other words, the above-mentioned method of replenishing air can only reduce the effects of negative pressure, cavitation, etc., but cannot fundamentally eliminate the problems caused by negative pressure and cavitation. Summary of the invention

[0007] The object of the present invention is to provide a cavitation reducing impeller and an aeration cavitation reducing impeller assembly, which can add water to the negative pressure area of ​​the blades, thereby balancing the pressure to reduce cavitation.

[0008] The embodiments of the present invention are implemented by the following technical solutions: A erosion-reducing impeller comprises a volute, a rotating shaft, a runner, a rotating disk and a plurality of blades; the runner and the rotating disk are arranged opposite to each other and a flow gap is reserved between the two; the volute is wrapped around the outside of the runner and is connected to the flow gap; a plurality of blades are evenly distributed in an annular shape inside the flow gap and are connected to the runner and the rotating disk; the rotating shaft is connected to the rotation center of the runner; the rotating shaft is tubular; channels are arranged inside the blades and the runner and the channels of the two are connected; the channel of the runner is connected to the inside of the rotating shaft; the channel of the blade extends to the surface of the negative pressure area of ​​the blade; the rotating disk is also provided with an opening to connect the flow gap with the outside.

[0009] Furthermore, a plurality of movable guide vanes are rotatably provided between the flow gap and the volute, so that the angle of the movable guide vanes is adjustable; and the plurality of movable guide vanes are distributed in a ring shape around the impeller.

[0010] Furthermore, it also includes an anti-backflow mechanism; the anti-backflow mechanism includes a ring seat and a plurality of anti-backflow sheets; the ring seat is arranged inside the rotating shaft; the plurality of anti-backflow sheets are hinged inside the ring seat, so that when the fluid flows through the blades to the rotating shaft, the plurality of anti-backflow sheets are closed together, and when the fluid flows through the rotating shaft to the blades, the plurality of anti-backflow sheets are opened.

[0011] Furthermore, it also includes an opening clamp and a closing clamp; the opening clamp and the closing clamp are arranged on both sides of the ring seat and are both coordinated with the anti-backflow plate, so that the anti-backflow plate abuts against the opening clamp when it swings to the opening limit and abuts against the closing clamp when it swings to the closing limit.

[0012] Furthermore, a mesh plate is provided on the surface of the blade at the channel.

[0013] An aeration cavitation reduction impeller assembly comprises an air pressure source, a metering control valve and the above-mentioned cavitation reduction impeller; the air pressure source is connected to the rotating shaft through the metering control valve.

[0014] Furthermore, it also includes an electronic flowmeter, a pressure stabilizing tank and a flow stabilizing tube; the rear end of the metering control valve is connected to the pressure stabilizing tank, the electronic flowmeter and the flow stabilizing tube in sequence; the flow stabilizing tube is connected to the inside of the rotating shaft.

[0015] Furthermore, the rotating shaft is provided with a rotating joint; the flow stabilizing tube is connected to the rotating shaft via the rotating joint.

[0016] Furthermore, the flow channel cross section inside the flow stabilizing tube is honeycomb-shaped.

[0017] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects: When the erosion-reducing impeller of the present invention is used, the impeller, the turntable and the blades rotate together, and water flows from the volute to the opening of the turntable or from the opening of the turntable to the volute under the action of the blades. At the same time, under the action of the blades themselves, the water pressure at both ends is different. Cavitation is easily formed in its negative pressure area. Therefore, air can be introduced through the hollow shaft, and at the same time, the air passes through the channels of the impeller and the blades to guide the air inside the shaft to the negative pressure area surface of the blades, thereby balancing the negative pressure in the impeller area and dispersing the vortex in the area, reducing the unstable flow between the impeller flow channels and reducing the occurrence of cavitation erosion. Compared with the use of additional fluid pipelines to transport airflow, the channels inside the shaft and the blades and impeller can effectively avoid the entanglement and interference of the pipeline when the main shaft rotates, greatly facilitating the structural layout and assembly.

[0018] A number of movable guide vanes are rotatably arranged between the flow gap and the volute, so that the angle of the guide vanes can be adjusted as needed, thereby allowing water entering through the volute to impact the blades at a better angle, allowing the blades to generate stronger power to generate electricity.

[0019] The anti-backflow mechanism allows water to flow only toward the blades and not backflow through the channel, ensuring that water can effectively flow to the surface of the blades.

[0020] The mesh plate allows air to flow through the channel to the blade surface, generating denser bubbles that enter the mixed flow area to balance negative pressure, reduce cavitation, and improve unstable flow phenomena. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a schematic diagram of an aeration cavitation reduction impeller assembly; Figure 2 is a schematic diagram of a erosion-reducing impeller; Figure 3 It is a schematic diagram of the coordination between the rotating shaft, the flow stabilizing tube and the runner; Figure 4 is a schematic diagram of a mesh plate; Figure 5 is a schematic diagram of a blade; Figure 6 It is a schematic diagram of the backflow prevention mechanism; Figure 7 A schematic diagram of the anti-backflow mechanism from the top perspective; Icons: 1-volute, 2-rotating shaft, 3-impedance, 4-turntable, 5-blade, 6-circulation gap, 7-channel, 8-movable guide vane, 9-ring seat, 10-anti-backflow plate, 11-open clamp, 12-closed clamp, 13-mesh plate, 14-air pressure source, 15-metering control valve, 16-electronic flow meter, 17-pressure regulating tank, 18-flow regulating tube, 19-swivel joint, 20-fixed guide vane, 21-tailwater pipe, 22-anti-backflow mechanism. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Example: like Figure 1-Figure 7 As shown, the present invention provides a erosion reduction impeller, comprising a volute 1, a rotating shaft 2, a runner 3, a rotating disk 4 and a plurality of blades 5. The runner 3 and the rotating disk 4 are arranged opposite to each other and a flow gap 6 is reserved between the two. The volute 1 is wrapped around the outside of the runner 3 and connected to the flow gap 6. Figure 2 As shown, the volute 1 is an annular tube with a groove on the inside, and the groove is connected to the flow gap 6. The turntable 4 is also provided with an opening to connect the flow gap 6 with the outside, and this opening is the tailwater pipe 21. The opening of the turntable 4 is arranged at its center. The volute 1 is also provided with an opening. When in use, water can enter the volute 1 through the opening of the volute 1, and then flow through the flow gap 6 to the opening of the turntable 4 and then flow out. Water can also flow into the flow gap 6 through the opening of the turntable 4 and then into the volute 1, and then flow out from the volute 1. The flow direction of the water flow can be selected according to the specific working conditions.

[0025] Several blades 5 are evenly distributed in the circulation gap 6 in an annular shape and connected to the runner 3 and the turntable 4. In practice, the upper and lower sides of the blades 5 are connected to the runner 3 and the turntable 4 respectively, so that the runner 3, the turntable 4 and the blades 5 are connected as a whole. The rotating shaft 2 is connected to the rotation center of the runner 3. When the runner 3 rotates, it can drive the runner 3, the turntable 4 and the blades 5 to rotate together. The rotation of the blades 5 can drive the internal water flow to flow.

[0026] The rotating shaft 2 is tubular and hollow inside. Channels 7 are provided inside the blades 5 and the runner 3, and the channels 7 of the two are connected. The channel 7 of the runner 3 is connected to the inside of the rotating shaft 2. The channel 7 of the blade extends to the surface of the negative pressure area of ​​the blade. In other words, by adding high-pressure water into the rotating shaft 2, the water can flow to the surface of the blade 5 through the channel 7.

[0027] When the erosion reduction impeller of the present invention is used, the runner 3, the turntable 4 and the blades 5 rotate together, and water flows from the volute 1 to the opening of the turntable 4 or from the opening of the turntable 4 to the volute 1 under the action of the blades 5. At the same time, under the action of the blades 5 themselves, the water pressure at both ends is different. Cavitation is easily formed in its negative pressure area. Therefore, air can be introduced through the hollow shaft 2, and at the same time, the air passes through the channel 7 of the runner 3 and the blades 5 to guide the air inside the shaft 2 to the surface of the negative pressure area of ​​the blades 5, thereby balancing the negative pressure in the runner 3 area and dispersing the vortex in the area, reducing the unstable flow between the flow channels of the runner 3 and reducing the occurrence of cavitation erosion. Compared with the use of additional fluid pipelines to transport airflow, the channel 7 inside the shaft 2 and the blades 5 and the runner 3 can effectively avoid the entanglement and interference of the pipeline when the main shaft rotates, which greatly facilitates the structural layout and assembly.

[0028] The forward and reverse rotation of the blades 5 switches the flow direction of the water flow inside, thereby adapting to the two working conditions of pumping and power generation. In the power generation condition, the water flows into the volute 1 and flows out of the tailwater pipe 21. In the pumping condition, the water flows into the tailwater pipe 21 and flows out of the volute to the water reservoir.

[0029] It can be seen that the erosion reduction impeller assembly of the present invention can be used as a water pump or a water turbine. For a water pump turbine, whether in the water turbine mode or the water pump mode, the downstream of the blade 5 is a low-pressure area and the area where cavitation is most likely to occur. Therefore, the channel 7 leads to the downstream of the blade 5, such as Figure 3 and Figure 5 The above structure and technical solution are applicable in both modes.

[0030] In this embodiment, a plurality of movable guide vanes 8 are rotatably provided between the flow gap 6 and the volute 1, so that the angle of the movable guide vanes 8 is adjustable. The plurality of movable guide vanes 8 are distributed in a ring around the runner 3. Specifically, the movable guide vanes 8 are similar to the blades 5 of a shutter, and the angle of the movable guide vanes 8 can be adjusted as needed to adjust the angle of the water flowing through the volute 1 into the flow gap 6, so that the water flow can better impact the blades 5, so that the blades 5 obtain greater kinetic energy and generate electricity better.

[0031] In addition, a fixed guide vane 20 is provided to cooperate with the movable guide vane 8, and the two cooperate with each other to better guide the water flow.

[0032] In this embodiment, a backflow prevention mechanism 22 is also included. Figure 3 , Figure 6 and Figure 7 As shown, the anti-backflow mechanism 22 includes a ring seat 9 and a plurality of anti-backflow sheets 10. The ring seat 9 is annular and is arranged inside the rotating shaft 2. The plurality of anti-backflow sheets 10 are hinged to the inside of the ring seat 9 so that the anti-backflow sheets 10 can be driven to swing when the airflow passes through. When the fluid flows to the rotating shaft 2 through the blade 5, the plurality of anti-backflow sheets 10 are closed together. Then the channel 7 inside the turning point is blocked. When the fluid flows to the sheet through the rotating shaft 2, the plurality of anti-backflow sheets 10 are opened. Then the channel 7 inside the rotating shaft 2 is opened. In other words, the direction of the airflow can be controlled by the anti-backflow sheets 10, so that the airflow can only flow to the surface of the blade 5 through the rotating shaft 2 and cannot flow in the opposite direction. Then the external airflow can continuously flow to the surface of the negative pressure area of ​​the blade 5.

[0033] In this embodiment, an opening clamp 11 and a closing clamp 12 are also included. The opening clamp 11 and the closing clamp 12 are arranged on both sides of the ring seat 9, thereby sandwiching the anti-backflow sheet 10 in the middle. The opening clamp 11 and the closing clamp 12 are both arranged in cooperation with the anti-backflow sheet 10, so that the anti-backflow sheet 10 abuts against the opening clamp 11 when it swings to the opening limit and abuts against the closing clamp 12 when it swings to the closing limit. This prevents the anti-backflow sheet 10 from swinging too much during the swinging process, but is limited by the opening clamp 11 and the closing clamp 12.

[0034] In this embodiment, a mesh plate 13 is provided on the surface of the blade 5 at the channel 7. Figure 4 and Figure 5As shown, the mesh plate 13 allows the air to generate denser bubbles when flowing through the channel 7 to the surface of the blade 5, so as to enter the mixed flow area to balance the negative pressure, reduce cavitation and improve the unstable flow phenomenon.

[0035] The present invention also provides an aerated cavitation reduction impeller assembly, comprising an air pressure source 14, a metering control valve 15 and the above-mentioned cavitation reduction impeller. The air pressure source 14 is connected to the rotating shaft 2 through the metering control valve 15. The air pressure source 14 is an air compressor, which is used to provide a high-pressure air source. Because the gas pressure generated by it is relatively large and the pressure is not easy to stabilize. In order to generate a smooth and adjustable airflow, the metering control valve 15 plays a role in quantitatively regulating the gas flow.

[0036] In this embodiment, an electronic flow meter 16, a pressure stabilizing tank 17 and a flow stabilizing tube 18 are also included. The rear end of the metering control valve 15 is connected to the pressure stabilizing tank 17, the electronic flow meter 16 and the flow stabilizing tube 18 in sequence. The flow stabilizing tube 18 is connected to the inside of the rotating shaft 2.

[0037] The gas enters the pressure stabilizing tank 17. A pressure gauge and a pressure regulating valve with high measurement accuracy are installed on the top of the pressure stabilizing tank 17, which can effectively detect and regulate the gas pressure. The high-pressure gas passing through the pressure stabilizing tank 17 can become a stable gas source. An electronic flow meter 16 is also provided between the pressure stabilizing tank 17 and the flow stabilizing tube 18, so as to monitor the gas flow rate, and judge whether backflow occurs according to the value displayed by the electronic flow meter 16.

[0038] In this embodiment, the rotating shaft 2 is provided with a rotating joint 19. The flow stabilizing tube 18 is connected to the rotating shaft 2 via the rotating joint 19. Figure 3 As shown, the rotary joint 19 ensures that the rotation of the rotating shaft 2 will not affect the flow stabilizing tube 18, thereby avoiding interference of the flow stabilizing tube 18.

[0039] In this embodiment, the flow passage cross section inside the flow stabilizing tube 18 is honeycomb-shaped, thereby playing a role in stabilizing the flow.

[0040] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A erosion reducing impeller, characterized in that: It includes a volute, a rotating shaft, a rotor, a turntable and a plurality of blades; the rotor and the turntable are arranged opposite to each other and a flow gap is reserved between the two; the volute is wrapped around the outside of the rotor and connected to the flow gap; a plurality of blades are evenly distributed in the flow gap in an annular shape and connected to the rotor and the turntable; the rotating shaft is connected to the rotation center of the rotor; the rotating shaft is tubular; channels are arranged inside the blades and the rotor and the channels of the two are connected; the channel of the rotor is connected to the inside of the rotating shaft; the channel of the blade extends to the surface of the negative pressure area of ​​the blade; the turntable is also provided with an opening to connect the flow gap with the outside.

2. The erosion reducing impeller according to claim 1, characterized in that: A plurality of movable guide vanes are rotatably arranged between the flow gap and the volute so that the angle of the movable guide vanes can be adjusted; the plurality of movable guide vanes are distributed in a ring shape around the impeller.

3. The erosion reducing impeller according to claim 2, characterized in that: It also includes an anti-backflow mechanism; the anti-backflow mechanism includes a ring seat and a plurality of anti-backflow sheets; the ring seat is arranged inside the rotating shaft; the plurality of anti-backflow sheets are hinged inside the ring seat, so that when the fluid flows through the blades to the rotating shaft, the plurality of anti-backflow sheets are closed together, and when the fluid flows through the rotating shaft to the blades, the plurality of anti-backflow sheets are opened.

4. The erosion reducing impeller according to claim 3, characterized in that: It also includes an opening clamp and a closing clamp; the opening clamp and the closing clamp are arranged on both sides of the ring seat and are both coordinated with the anti-backflow plate, so that the anti-backflow plate abuts against the opening clamp when it swings to the opening limit and abuts against the closing clamp when it swings to the closing limit.

5. The erosion reducing impeller according to claim 4, characterized in that: A mesh plate is arranged on the surface of the blade at the channel.

6. An aeration cavitation reduction impeller assembly, characterized in that: It comprises an air pressure source, a metering control valve and the erosion reducing impeller according to any one of claims 1 to 5; the air pressure source is connected to the rotating shaft through the metering control valve.

7. The aeration cavitation reduction impeller assembly according to claim 6, characterized in that: It also includes an electronic flow meter, a pressure stabilizing tank and a flow stabilizing tube; the rear end of the metering control valve is connected to the pressure stabilizing tank, the electronic flow meter and the flow stabilizing tube in sequence; the flow stabilizing tube is connected to the inside of the rotating shaft.

8. The aeration cavitation reduction impeller assembly according to claim 7, characterized in that: The rotating shaft is provided with a rotating joint; the flow stabilizing tube is connected to the rotating shaft through the rotating joint.

9. The aeration cavitation reduction impeller assembly according to claim 8, characterized in that: The flow channel cross section inside the flow stabilizing tube is honeycomb-shaped.

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