A hydraulic turbine unit tailrace pipe comprising a gas-solid coupling type vortex band suppression device

Abstract

The utility model discloses a water turbine set draft tube containing gas -solid coupling formula vortex belt suppression device, through setting up air supplementing pipeline and air inlet device, can when the unit appears unstable condition, supplement into air, destroy vortex belt, is used for reducing vibration, prevents cavitation erosion and reduces whirlpool intensity, sets up support piece, can fix air supplementing pipeline at the same time to the support effect of pipe wall, reduce the vibration of disadvantage factor, sets up the flow guide component, can destroy vortex belt stability when the water flow passes, prevents the damage of overflow part, through the mutual coupling of air supplementing and fixed flow guide component, support piece, guarantee the stable operation of unit to a great extent, compared with traditional single air supplementing mode, this scheme can further reduce the disadvantageous influence that vortex belt of draft tube produces to unit operation.

Description

Technical Field

[0001] This utility model relates to the field of tailrace pipe technology for hydro turbine units, specifically a tailrace pipe for hydro turbine units that includes a gas-solid coupling vortex band suppression device. Background Technology

[0002] When a turbine unit operates under partial or overload conditions, the water flow at the runner outlet deviates from the normal direction, forming an eccentrically rotating vortex. This eccentric vortex moves downward in a spiral band, forming a vortex belt. The rotation and flow of the vortex belt in the draft tube will generate low-frequency pressure pulsations and may even cause hydraulic resonance, which will seriously affect the stable operation of the unit.

[0003] Pressure pulsations caused by vortex bands not only increase unit vibration and noise but can also damage the unit's structure and shorten its service life. Furthermore, pressure pulsations caused by vortex bands can trigger other hydraulic problems such as cavitation and cavitation erosion (cracks appearing in flow-through components), further exacerbating the unit's instability. Traditional solutions to vortex bands simply involve adding an air supply device at the discharge cone, but relying solely on air supply has limited ability to suppress vortex bands. Utility Model Content

[0004] (1) Technical problem to be solved: In order to further reduce the adverse effects of the tailrace vortex on the operation of the unit, a tailrace of a turbine unit including a gas-solid coupling vortex suppression device is provided.

[0005] (2) The technical solution adopted by this utility model is as follows: a turbine tailrace pipe including a gas-solid coupling vortex band suppression device, the tailrace pipe includes a water inlet and a water outlet, the vortex band suppression device includes an air supply pipe set inside the tailrace pipe, one end of the air supply pipe is located at the water inlet, and the end of the air supply pipe at the water inlet is connected to an air intake device, the air supply pipe is arranged along the center line of the tailrace pipe, the other end of the air supply pipe is open and extends to the water outlet, air holes are evenly distributed on the air supply pipe, the air supply pipe is fixedly connected to the tailrace pipe through a support member, and a flow guiding component is set on the air supply pipe.

[0006] A further technical solution is that the flow guiding component includes multiple flow guiding vanes arranged in the circumferential direction along the gas supply pipeline.

[0007] A further technical solution is that the air intake device is an air replenishment valve, which is located inside the water discharge cone of the turbine unit.

[0008] (3) Due to the adoption of the above technical solution, the beneficial effects of this utility model are as follows: by setting up an air supply pipe and an air intake device, air can be supplied when the unit is in unstable operating conditions to destroy the vortex band, thereby reducing vibration, preventing cavitation and reducing vortex intensity. The support component can support the pipe wall while fixing the air supply pipe, reducing vibration caused by adverse factors. The flow guiding component can destroy the stability of the vortex band when water flows through, preventing damage to the flow components. Through the mutual coupling of air supply and fixed flow guiding component and support component, the stable operation of the unit is largely guaranteed. Compared with the traditional single air supply method, this solution can further reduce the adverse effects of the tailrace vortex band on the operation of the unit.

[0009] Moreover, the main location for vortex formation is directly below the turbine outlet. After formation, it extends downstream along the central axis to the straight cone section and the elbow section. Upon reaching the diffuser section, it may split into multiple small vortices due to impact with the pipe wall, causing more complex fluctuations. Therefore, in order to ensure that the vortex of the entire tailrace pipe can be effectively suppressed, an air supply pipe is laid along the central axis. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0011] Figure 2 This is a schematic diagram of the connection structure of the air supply valve inside the drain cone;

[0012] Figure 3 This is a schematic diagram of the structure of the guide plate described in this utility model;

[0013] Figure 4 This is a schematic diagram of the overall structure corresponding to Embodiment 2 of this utility model. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0015] like Figures 1-4 As shown.

[0016] Example 1: A turbine draft tube 1 including a gas-solid coupling vortex band suppression device. The draft tube 1 includes a water inlet 2 and a water outlet 3. The vortex band suppression device includes an air supply pipe 4 installed inside the draft tube 1. One end of the air supply pipe 4 is located at the water inlet 2, and an air intake device is connected to the end of the air supply pipe 4 at the water inlet 2. The air supply pipe 4 is arranged along the centerline of the draft tube 1, and the other end of the air supply pipe 4 is open and extends to the water outlet 3. Air holes 6 are evenly distributed on the air supply pipe 4. The air supply pipe 4 is fixedly connected to the draft tube 1 by a support member 7. A flow guiding assembly is installed on the air supply pipe 4. The flow guiding assembly includes multiple flow guide vanes 8 arranged circumferentially along the air supply pipe 4. The air intake device is an air supply valve 10, which is located inside the turbine's drain cone 13.

[0017] In operation, the inlet of the draft tube 1 of the turbine unit is connected to the spiral casing of the turbine unit. The drain cone 13 is located directly above the inlet of the draft tube 1. The upper end of the air supply pipe 4 extends into the drain cone 13. The upper part of the drain cone 13 is the turbine shaft. Traditionally, the air supply method utilizes the hollow turbine shaft and the drain cone 13 as the air intake channel. Therefore, the upper end of the air supply pipe 4 is placed inside the drain cone 13 (the air supply pipe 4 is welded to the bottom of the drain cone 13), and an air supply valve 10 is installed at the upper end of the air supply pipe 4. The air supply valve 10 does not require connection to an external compressed air source. When a vortex is generated in the draft tube 1, a vacuum cavity is formed inside. The pressure difference causes the valve core of the air supply valve 10 to push... When the air supply valve 10 in this invention is opened (it is the same as the air supply valve 10 used in the existing tailwater pipe 1), external air is "drawn" into the tailwater pipe 1 under atmospheric pressure. The external air enters the air supply pipe 4 through the air supply valve 10 and then enters the tailwater pipe 1 through the air holes 6 on the air supply pipe 4. Since the air holes 6 are evenly distributed, air can be supplied to the tailwater pipe 1 to disrupt the vortex band and reduce the vortex intensity. The air supply pipe 4 can guide the air to a deeper position where a vacuum cavity is formed when the vortex band is generated. Because if a vacuum cavity exists, there is no water inside the part of the air supply pipe 4 that is in the vacuum cavity, so air can be supplied to a deeper position in the vacuum cavity. Since the rotation and flow of the vortex band in the tailwater pipe 1 will generate low-frequency pressure pulsations and even cause hydraulic resonance, the support member 7 can support the tailwater pipe 1 itself and fix the air supply pipe 4 at the same time. The support component 7 adopts the form of cross support rods 12. The flange 11 is welded to the air supply pipe 4. The four support rods 12 are evenly distributed and welded to the flange 11. The other end of the four support rods 12 is then fixed to the inner wall of the tailwater pipe 1. In the flow guiding assembly, the guide plate 8 is welded to the flange 11 and is spaced apart from the support rods 12. The outer edge of the guide plate 8 is serrated. The serrated outer edge of the guide plate 8 disrupts the stability of the vortex when water flows through (the tail of the guide plate 8 is far away from the air supply pipe 4), preventing damage to the flow components. The large tailwater pipe 1 can allow personnel to enter to install the air supply pipe 4. The small tailwater pipe 1 can be segmented at the position corresponding to the support component 7. After the support component 7 is installed, it is welded into a whole. At least two support components 7 are provided.

[0018] In addition, the main location for vortex formation is directly below the turbine outlet. After formation, it extends downstream along the central axis to the straight cone section and the elbow section. After reaching the diffuser section, it may split into multiple small vortices due to impact with the pipe wall, causing more complex fluctuations. Therefore, in order to ensure that the vortex of the entire tailrace pipe can be effectively suppressed, an air supply pipe is laid along the central axis.

[0019] Example 2: The difference from Example 1 is that the air intake device is a vent pipe 9 and an air replenishment valve 10. The vent pipe 9 is connected to the air replenishment pipe 4. The vent pipe 9 extends out of the tailwater pipe 1 in the radial direction. In use, the vent pipe 9 is ultimately in the outside air. The air replenishment valve 10 is installed on the vent pipe 9. This method does not require the use of a hollow water turbine shaft and a drain cone 13 as the air intake channel.

[0020] The above are merely preferred embodiments of this utility model.

Claims

1. A draft tube for a turbine generator unit comprising a gas-solid coupling vortex band suppression device, the draft tube (1) including a water inlet (2) and a water outlet (3), characterized in that, The vortex suppression device includes an air supply pipe (4) installed inside the tailwater pipe (1). One end of the air supply pipe (4) is located at the water inlet (2), and the end of the air supply pipe (4) at the water inlet (2) is connected to an air intake device. The air supply pipe (4) is laid along the center line of the tailwater pipe (1), and the other end of the air supply pipe (4) is open and extends to the water outlet (3). Air holes (6) are evenly distributed on the air supply pipe (4). The air supply pipe (4) is fixedly connected to the tailwater pipe (1) through a support member (7). A flow guiding component is installed on the air supply pipe (4).

2. The draft tube of a turbine unit including a gas-solid coupling vortex suppression device according to claim 1, characterized in that, The flow guiding assembly includes multiple flow guiding vanes (8) arranged in the circumferential direction along the gas supply pipe (4).

3. The draft tube of a turbine unit including a gas-solid coupling vortex suppression device according to claim 1, characterized in that, The air intake device is a supplementary air valve (10), which is located inside the water discharge cone of the turbine unit.

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