CN214063193U

CN214063193U - Take mixed-flow turbine leak stopping device of self-balancing function

Info

Publication number: CN214063193U
Application number: CN202022678840.7U
Authority: CN
Inventors: 吴广宽; 冯亚军; 冯建军; 罗兴锜; 付永远
Original assignee: Xian University of Technology
Current assignee: Xian University of Technology
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2021-08-27
Anticipated expiration: 2030-11-18

Abstract

The utility model discloses a take mixed-flow hydraulic turbine leak-stopping device of self-balancing function, including hydraulic turbine runner lower ring, the outside cover of hydraulic turbine runner lower ring is equipped with the end ring, and this leak-stopping device sets up in the clearance between hydraulic turbine runner lower ring and end ring, and hydraulic turbine runner lower ring outside wall is provided with helical blade, helical blade's soon to with hydraulic turbine main shaft's direction of rotation opposite. A plurality of grooves are uniformly arranged on the inner wall surface of the bottom ring along the circumferential direction. The leakage stopping device can enable water flow at the inlet of the runner to flow into the runner as far as possible, so that the gap leakage flow is reduced, the volume loss of water flow is reduced, and the efficiency of the whole hydroelectric generating set is improved.

Description

Take mixed-flow turbine leak stopping device of self-balancing function

Technical Field

The utility model belongs to the technical field of hydraulic machinery auxiliary assembly, concretely relates to take mixed flow turbine leak stopping device of self-balancing function.

Background

The function of the leakage stopping device of the mixed-flow water turbine is to reduce the volume loss of the unit. The prior common use comprises three types, namely a gap type, a labyrinth type and a comb type. The upper leakage-stopping device is arranged in a gap between the upper crown of the rotating wheel and the front cover plate (top cover), and the lower leakage-stopping device is arranged in a gap between the lower ring and the bottom ring of the rotating wheel.

When rivers flow through the leak-stopping ring, the runner expands often, contracts often, and its purpose is for the local resistance and the on-way resistance of increase to rivers for rivers energy dissipation in the leak-stopping device, the velocity of flow reduces, thereby reaches the purpose that reduces to leak. When the mixed-flow water turbine normally operates, a part of water flow passes through the inlet of the water turbine runner, because a gap exists between the bottom ring of the water turbine and the water turbine runner and a pressure difference exists between the upstream and the downstream, the water flow flows into the leakage stopping ring from the gap between the bottom ring and the runner and finally flows into the downstream of the draft tube. Because the part of water flow does not enter the runner to do work, a part of volume loss is caused, and the water flow flowing through the leakage stopping ring can also influence the pressure distribution of the water flow at the inlet of the draft tube, so that a draft tube vortex band is formed, the vibration of the unit is generated, and the operation of the water-turbine generator set is unstable.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a take mixed-flow turbine leak stopping device of self-balancing function through reducing clearance leakage flow, reduces hydraulic turbine volumetric loss's purpose to improve hydraulic turbine generating set efficiency.

The utility model provides a technical scheme who adopts is, a take mixed flow turbine leak-stopping device of self-balancing function, including hydraulic turbine runner lower ring, the outside cover of hydraulic turbine runner lower ring is equipped with the end ring, and this leak-stopping device sets up in the clearance between hydraulic turbine runner lower ring and end ring, and hydraulic turbine runner lower ring outside wall is provided with helical blade, has evenly seted up a plurality of recesses along circumference on the internal face of end ring.

The utility model is also characterized in that,

the rotation direction of the helical blade is opposite to the rotation direction of the main shaft of the water turbine.

The height ratio of the total height of the helical blade to the lower ring of the turbine runner is 1: 1.

the ratio of the pitch of the helical blades to the height of the lower ring of the turbine runner is 0.1: 1.

the ratio of the thickness of the helical blade to the height of the lower ring of the turbine runner is 0.025: 1.

the groove is a rectangular groove; the ratio of the width of the groove to the height of the lower ring of the water turbine runner is 0.025: 1; the diameter ratio of the depth of the groove to the lower ring of the water turbine runner is 0.01: 1.

the utility model has the advantages that,

the device can make runner entry rivers flow into the runner as far as possible, has reduced the clearance leakage flow, has reduced the volumetric loss of rivers to improve whole hydroelectric set efficiency.

Drawings

Fig. 1 is a schematic structural diagram of a mixed-flow water turbine leakage stopping device with a self-balancing function of the present invention;

fig. 2 is a partial enlarged view of the leakage stopping device of the mixed-flow water turbine with self-balancing function of the present invention.

In the figure, 1 is an upper crown, 2 is a runner blade, 3 is a helical blade, 4 is a bottom ring, 5 is a turbine runner lower ring, and 6 is a groove.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

The utility model relates to a take mixed flow turbine leak stopping device of self-balancing function, as shown in figure 1, the mixed flow turbine includes runner blade 2, is provided with crown 1 on runner blade 2, and runner blade 2 lower part is provided with hydraulic turbine runner lower ring 5, and the outside cover of hydraulic turbine runner lower ring 5 is equipped with bottom ring 4, and this leak stopping device sets up in the clearance between hydraulic turbine runner lower ring 5 and bottom ring 4, as shown in figure 2, including setting up the helical blade 3 at the outer side wall of hydraulic turbine runner lower ring 5, evenly seted up a plurality of recesses 6 along circumference on the internal wall of bottom ring 4; the groove 6 can be a rectangular groove;

the rotation direction of the helical blade 3 is opposite to the rotation direction of the main shaft of the water turbine; therefore, upward pumping flow can be generated, the leakage stopping effect is achieved, otherwise, the leakage flow can be increased, and the generating efficiency of the hydraulic turbine set is reduced.

The ratio of the total height of the helical blades 3 to the height of the lower ring 5 of the turbine runner is 1: 1; the ratio of the spacing width between the two grooves with the farthest distance to the height of the lower ring of the runner of the water turbine is 1: 1. The setting can lead the leakage flow to directly enter the spiral runner and the labyrinth runner in the leakage stopping device from the gap inlet, thereby increasing the hydraulic loss along the way and enhancing the leakage stopping effect.

The ratio of the pitch of the helical blades 3 to the height of the lower ring 5 of the turbine runner is 0.1: 1. the proper pitch can prolong the length of the spiral flow passage, thereby increasing the hydraulic loss along the way to enhance the leakage-stopping effect.

The ratio of the thickness of the helical blade 3 to the height of the lower ring 5 of the turbine runner is 0.025: 1.

the ratio of the width of the groove 6 to the height of the lower ring 5 of the turbine runner is 0.025: 1;

the diameter ratio of the outer edge diameter of the spiral blade 3 to the runner lower ring 5 of the water turbine is 1.01: 1; the diameter ratio of the top clearance between the spiral blade 3 and the groove 6 to the runner blade 2 is 0.001: 1; the diameter ratio of the depth of the groove 6 to the lower ring 5 of the turbine runner is 0.01: 1. the setting enables the cross section area of a flow channel of the leakage stopping device to change, when water flow enters a contraction flow channel, pressure energy is converted into kinetic energy, and the flow velocity of the water flow is maximum; when water flow enters the expanding flow channel, the cross section of the flow channel is suddenly increased, so that strong vortex is formed in the flow channel. The most kinetic energy of the water flow is converted into heat energy as a result of vortex friction, so that the energy dissipation of the water flow in the flowing process is enhanced, the flow velocity of the water flow is reduced, the leakage flow is reduced, and the leakage stopping effect is enhanced.

The utility model relates to a take mixed-flow turbine leak stopping device of self-balancing function, its concrete theory of operation is:

will the utility model discloses a leak-stopping device installs 5 and 4 cooperation departments of end ring in hydraulic turbine runner bottom ring, and it will be opposite to notice that helical blade 3 will revolve with the hydraulic turbine main shaft. When the water turbine operates under a rated working condition, because the rotation directions are opposite, the spiral blades 3 on the outer side of the lower ring 5 of the rotating wheel of the water turbine do work on water flow at the inlet of the draft tube, the water flow generates a pumping flow phenomenon under the action of fluid viscous shearing force, the water flow at the inlet of the draft tube is reversely pumped into the leakage stopping device, and therefore the downward leakage flow and the upward pumping flow are simultaneously in the leakage stopping device. Under the effect of the self-balancing sealing device, the inlet water pressure and the outlet water pressure of the gap between the bottom ring 4 of the water turbine and the lower ring 5 of the runner of the water turbine are equal, the upstream and downstream stress of the water flow in the gap is balanced, and the leakage flow and the pumping flow are mutually offset.

On the other hand, the groove 6 and the helical blade 3 are matched to form a labyrinth type flow passage, and the flow passage contracts and expands sometimes. When water flow enters the contraction flow channel, pressure energy is converted into kinetic energy, and the flow velocity of the water flow is maximum at the moment; when water flow enters the expanding flow channel, the cross section of the flow channel is suddenly increased, so that strong vortex is formed in the flow channel. As a result of vortex friction, most kinetic energy of water flow is converted into heat energy, energy dissipation of the water flow in the flowing process is enhanced, and the flow speed of the water flow is reduced. Therefore, the gap leakage flow is reduced, most of water flow at the inlet of the rotating wheel flows into the rotating wheel when flowing through the gap, the volume loss of the water turbine is effectively reduced, and the efficiency of the whole water turbine generator set is improved.

Claims

1. The utility model provides a take mixed-flow hydraulic turbine leak stopping device of self-balancing function, includes hydraulic turbine runner lower ring (5), the outside cover of hydraulic turbine runner lower ring (5) is equipped with bottom ring (4), and this leak stopping device sets up in the clearance between hydraulic turbine runner lower ring (5) and bottom ring (4), its characterized in that, hydraulic turbine runner lower ring (5) outside wall is provided with helical blade (3), evenly seted up a plurality of recesses (6) along circumference on the internal face of bottom ring (4).

2. The francis turbine leakage stopping device with the self-balancing function of claim 1, wherein the spiral blade (3) rotates in the direction opposite to the rotation direction of the main shaft of the turbine.

3. The francis turbine runner leakage stopping device with the self-balancing function of claim 1, wherein the ratio of the total height of the helical blades (3) to the height of the turbine runner lower ring (5) is 1: 1.

4. the francis turbine runner leakage stopping device with the self-balancing function of claim 1, wherein the ratio of the pitch of the helical blades (3) to the height of the turbine runner lower ring (5) is 0.1: 1.

5. the francis turbine wheel leakage stopping device with the self-balancing function of claim 1, wherein the ratio of the thickness of the helical blade (3) to the height of the turbine wheel lower ring (5) is 0.025: 1.

6. the francis turbine runner stop device with the self-balancing function according to claim 1, wherein the groove (6) is a rectangular groove; the ratio of the width of the groove (6) to the height of the lower ring (5) of the water turbine runner is 0.025: 1; the diameter ratio of the depth of the groove (6) to the lower ring (5) of the water turbine runner is 0.01: 1.