CN103807084A - Eddy elimination device in hydraulic turbine runner body - Google Patents

Abstract

The vortex elimination device in the runner body of the water turbine includes the vortex elimination blade installed on the discharge cone in the water turbine runner body. The vortex elimination blade is located between the roots and edges of the blades of two adjacent runners. The diameter of the vortex elimination blade is less than The diameter of the runner blades, the number of vortex elimination blades are consistent with the runner blades. The invention can effectively eliminate the tail water vortex belt, reduce the pressure pulsation, increase the service life of the water turbine unit, and can effectively recover the energy of the tail water vortex belt, thereby improving the efficiency of the water turbine.

Description

Vortex Elimination Device in the Runner Body of Water Turbine

technical field

The invention relates to the technical field of water turbines, in particular to an axial flow paddle water turbine, and in particular to a device for eliminating tail water vortexes installed on a discharge cone in a runner body.

Background technique

Water turbines and auxiliary machines are essential components of the hydropower industry, and important equipment for making full use of clean and renewable energy to achieve energy conservation, emission reduction, and environmental pollution reduction. As one of the most important equipment in current power generation technology, the water turbine has high efficiency, but there is still a certain loss of efficiency, especially the runner blades will cause the tail water vortex under partial load. For the water turbine unit adverse effects of vibration. Specifically, at the outlet of the water flow at the trailing edge of the runner blade, if the outlet water flow velocity has the same tangential velocity as the runner rotation direction and the outlet velocity value is large, a vortex will be formed in the draft tube, causing the turbine unit to The operation is unstable, and when the velocity of the outlet water flow is tangential to the direction opposite to the rotation direction of the runner, at the outlet of the runner, two rotating flows in opposite directions will be formed, and the two flows will collide with each other, consuming energy and increasing the Kinetic energy loss at the water outlet of the runner blade trailing edge and in the draft tube. In the prior art, the main measure used to eliminate the tail water vortex is to supply air between the guide vane and the runner vane or in the draft pipe to reduce the water pressure pulsation. However, due to the installation of additional equipment, which reduces the efficiency of the turbine.

Contents of the invention

The applicant improves the above-mentioned shortcomings in the prior art, and provides a vortex elimination device in the runner body of the water turbine, which can effectively eliminate the tail water vortex, reduce pressure pulsation, increase the service life of the water turbine unit, and can effectively recover The tailwater vortex carries energy and improves the efficiency of the turbine.

Technical scheme of the present invention is as follows:

The vortex elimination device in the runner body of the water turbine includes the vortex elimination blade installed on the discharge cone in the water turbine runner body, the vortex elimination blade is located between two adjacent runner blades, and the diameter of the vortex elimination blade is smaller than the runner blade diameter of.

Its further technical scheme is:

The number of the vortex-eliminating blades is consistent with that of the runner blades.

The vortex-eliminating blades are located in the middle of the edges of the blade roots of two adjacent runner blades.

The ratio of the diameter of the vortex-eliminating blade to the diameter of the rotor blade is 0.27-0.32.

The absolute value of the difference between the rotation angle of the vortex elimination blade and the rotor blade rotation angle is less than or equal to 6°

Technical effect of the present invention:

The invention installs vortex elimination blades on the discharge cone, so that the vortex that falls off on the discharge cone and the tailwater vortex belt generated by the interaction of the runner blades encounters the action of the vortex elimination blades when initially moving to the draft pipe of the hydraulic turbine , the vortex is broken up by the vortex-eliminating blades, so that strong vortex bands can no longer be formed in the draft tube, and the wake field becomes peaceful and stable, thereby effectively eliminating the tail water vortex bands, reducing the pulsation source that causes pressure pulsation, and reducing vibration , which reduces the possibility of cavitation in the draft tube cavity and prolongs the service life of the turbine unit; at the same time, the vortex-eliminating blade generates a torque in the same direction as the rotor blade in the process of breaking up the tailwater vortex, so that The energy of the tailwater vortex is converted into the torque of the same rotation direction of the runner blade on the vortex elimination blade, which effectively recovers the energy of the tailwater vortex, thereby improving the efficiency of the turbine.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is the force schematic diagram of the present invention in the water flow field, in the figure T represents the water thrust that the runner blade is subjected to, M represents the moment produced by the water thrust that the runner blade is subjected to, and T' represents the force that the vortex elimination blade is subjected to Water thrust, M' represents the moment generated by the water thrust of the vortex-eliminating blade, and the water thrust direction of the two in the figure is the same.

Fig. 3 is a schematic diagram of the installation position relationship between the vortex elimination blade and the runner blade according to the present invention.

Among them: 1. Drain cone; 2. Vortex elimination blade; 3. Runner paddle; 4. Runner hub.

Detailed ways

The specific implementation manner of the present invention will be described below in conjunction with the accompanying drawings.

See Fig. 1, the vortex elimination device of the present invention comprises the vortex elimination blade 2 installed on the discharge cone 1 in the runner body of the axial flow propeller type water turbine, the vortex elimination blade 2 is located between two adjacent runner blades 3 Between, the diameter of vortex-eliminating blade 2 is less than the diameter of runner blade 3.

Further, in order to maintain the structural symmetry balance of the entire water turbine runner body, preferably, the number of the vortex elimination blades 2 and the runner blades 3 is consistent, and preferably the vortex elimination blades 2 are located between two adjacent runner blades. The middle of the distance between the root of the blade 3 and the edge, as shown in Figure 3, the distance between the roots of the blade 3 of two adjacent runners is L, and the vortex-eliminating blade 2 is located at the root of the blade 3 of the two adjacent runners. In the middle, the distance between the vortex-eliminating blade 2 and the trailing sides of the roots of two adjacent runner blades 3 is L/2. The extension line positions the vortex-eliminating blade 2; in order to achieve the optimal vortex-eliminating effect, the ratio of the diameter of the vortex-eliminating blade 2 to the diameter of the runner blade 3 is controlled within the range of 0.27 to 0.32; in order to further ensure the operation Stability, the absolute value of the difference between the angle of rotation of the vortex-eliminating blade 2 and the angle of rotation of the rotor blade 3 is less than or equal to 6°, the concept of "rotation angle" is well known in the art, that is, the blade is relatively The angle at which the design position turns to the opening direction or the closing direction.

Under the condition that the vortex-eliminating blade 2 of the present invention is not installed, under a certain load, due to the water flow velocity at the water flow outlet of the runner blade 3 trailing edge can produce the same tangential velocity as the runner blade 3 rotation direction, As a result, a relatively strong vortex is formed at the water outlet of the runner blade 3 trailing edge and in the draft tube. This tail water vortex will cause pressure fluctuations, thereby affecting the operation stability of the water turbine unit. In order to solve this technical problem, The present invention adopts the improved scheme of installing vortex-eliminating blades 2 on the discharge cone 1, so that the tailwater vortex produced by the interaction of the shedding vortex on the discharge cone 1 and the runner blade 3 is initially directed towards the draft tube of the hydraulic turbine. When moving, the vortex is broken up by the vortex-eliminating blade 2, and at this time, the tangential velocity at the root of the runner blade 3 is weakened, so that the blade back pressure of the runner blade 3 increases, The axial water thrust of the runner blade 3 is reduced; at the same time, due to the elimination of the tail water vortex behind the discharge cone 1, the pressure drop on the runner hub 4 and the discharge cone 1 is reduced, thereby reducing the speed of rotation. The resistance on the wheel hub 4 and the water discharge cone 1; at the same time, the vortex-eliminating blade 2 produces the force and moment in the same direction as the runner blade 3, which increases the water thrust of the whole water turbine, and the moment generated by the water thrust increases, thereby improving The efficiency of the water turbine is shown in Figure 2. In Figure 2, T represents the water thrust received by the runner blade 3, M represents the moment generated by the water thrust received by the runner blade 3, and T' represents the water thrust received by the vortex-eliminating blade 2. M' represents the moment generated by the water thrust received by the vortex-eliminating blade 2. In the figure, the direction of the water thrust is the same. Converted into the torque M' of the vortex-eliminating blade 2, thereby improving the efficiency of the water turbine. On the other hand, the elimination of the tailwater vortex makes the tailwater flow field more peaceful and stable, reduces the possibility of cavitation in the draft tube cavity, reduces vibration, and prolongs the service life of the turbine unit.

The above description is an explanation of the present invention, not a limitation of the invention. For the limited scope of the present invention, please refer to the claims. Within the protection scope of the present invention, any form of modification can be made. the

Claims (5)

1. The vortex elimination device in the turbine runner body is characterized in that: it includes the vortex elimination blade (2) installed on the water discharge cone (1) in the turbine runner body, and the vortex elimination blade (2) is located on two adjacent runners Between the blades (3), the diameter of the vortex-eliminating blade (2) is smaller than the diameter of the runner blade (3). 2. The vortex elimination device in the runner body of the water turbine according to claim 1, characterized in that: the number of the vortex elimination blades (2) is the same as that of the runner blades (3). 3. The vortex elimination device in the runner body of the water turbine according to claim 1, characterized in that: the vortex elimination blade (2) is located in the middle of the edges of the roots of two adjacent runner blades (3). 4. The vortex elimination device in the runner body of the water turbine according to claim 1, characterized in that the ratio of the diameter of the vortex elimination blade (2) to the diameter of the runner blade (3) is 0.27-0.32. 5. The vortex elimination device in the turbine runner body according to claim 1, characterized in that: the absolute value of the difference between the rotation angle of the vortex elimination blade (2) and the rotation angle of the runner blade (3) is less than or equal to 6°.

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