EP3423703A1

EP3423703A1 - Water turbine, in particular axial turbine, and hydroelectric power plant having said water turbine

Info

Publication number: EP3423703A1
Application number: EP17706484.7A
Authority: EP
Inventors: Jan Niko HÄUSER
Original assignee: Wobben Properties GmbH
Current assignee: Wobben Properties GmbH
Priority date: 2016-03-04
Filing date: 2017-02-22
Publication date: 2019-01-09
Also published as: DE102016203596A1; WO2017148756A1

Abstract

The invention relates to a water turbine (11) for a hydroelectric power plant (1), and to a hydroelectric power plant (1) of this type. It is proposed that the water turbine has a flow duct (12) with a flow inlet (13) and a flow inlet (15), a turbine rotor (17) which is arranged in the flow duct (12) with a rotational axis (X), a ring generator for generating electric power with a generator rotor (25) and a generator stator (27), wherein the generator rotor (25) is connected fixedly to the turbine rotor (17) so as to rotate with it, forming a rotor unit (35), and a bearing unit (31a, b) for absorbing the radial and axial forces which act on the rotor unit, wherein the bearing unit is arranged radially outside the flow duct (12) in relation to the rotational axis (X). It is proposed according to the invention that the bearing unit is water-lubricated, wherein the bearing unit has a water inlet (55a) which is connected in a fluid-conducting manner to a dedicated water reservoir (57).

Description

Hydro turbine, in particular axial turbine, and hydroelectric power plant with selbiger

The present invention relates to a water turbine for a hydroelectric power plant, as well as a hydroelectric power plant with selbiger.

Turbines are used in hydroelectric power plants to generate electrical energy by rotationally driving their turbine blades by utilizing the kinetic energy of a water flow. In this case, a distinction is fundamentally made between turbines which transmit torque via a rotor shaft to a region outside a flow channel, whereupon the torque present at the rotor shaft is used to drive a generator, and those turbines in which the turbine rotors are directly connected to a rotor of a generator are connected. The first-mentioned types are known inter alia from DE 10 2008 045 500 A1. In the latter case one speaks of so-called straight-flow turbines. If the axis of rotation of the turbines is essentially parallel to the flow direction of the water, this is referred to as axial turbines.

All turbine types, especially the axial turbines, have in common the challenge that the turbine blades have high axial forces due to the pressure of the water. Furthermore, the turbines reach high rotational speeds of their rotors, which in particular in conjunction with the forces to be absorbed causes wear. The forces acting on the basis of the axial forces and due to the rotation forces are absorbed in the prior art of single or multi-row rolling bearing assemblies, which support the rotor shaft in the manner of an inner bearing and are arranged substantially centrally in the flow channel. Usually, in the prior art, these bearings are held by separate support means, which may be arranged, for example, in the nozzles adjacent to the turbine rotors themselves.

The known type of storage on the one hand has the disadvantage that for the inner bearing free flow cross-section must be sacrificed in the flow channel. On the other hand, due to the limited space available due to high surface pressures, potentially wear occurs at the bearings.

It is also conceivable in extreme cases that leak in case of failure of the bearing seals or the bearing lubricant itself and can contaminate the water flowing through the turbine. Against this background, the invention was based on the object of specifying a water turbine of the type described at the outset as well as a hydroelectric power station with the same, which overcome the aforementioned disadvantages as far as possible. In particular, the invention had the object of specifying a water turbine and a hydroelectric power plant, which have a reduced susceptibility to wear. Furthermore, the invention was in particular the object of specifying a water turbine and a hydroelectric power plant, in which a contamination of the flowing water with lubricant can be reliably avoided. Furthermore, the invention was particularly the task of specifying a water turbine and a hydroelectric power plant, which allow a compact design with high efficiency in power generation.

The invention solves the underlying task by proposing a water turbine with the features of claim 1. The water turbine according to the invention comprises a flow channel having a flow inlet and a flow outlet, a turbine rotor arranged in the flow channel with a rotation axis, a ring generator for generating electrical energy with a generator rotor and a generator stator, wherein the generator rotor with the turbine rotor rotatably connected to a rotor unit is and a bearing unit for receiving the force acting on the rotor unit radial axial forces, wherein the bearing unit relative to the Rotation axis is arranged radially outside the flow channel. If, in connection with the invention, a ring generator is used, this is preferably understood to mean a gearless, externally excited synchronous generator.

The invention makes use of the knowledge that two advantages can be achieved at the same time by abandoning the established concept of inner storage. Because the bearing unit is arranged radially outside the flow channel, the bearings of the bearing unit inevitably have larger bearing surfaces than would be feasible in the interior of the flow channel. This reduces the surface pressure acting on the bearing surfaces, resulting in a significant reduction of potential wear. Furthermore, contamination of the flow channel with lubricant is excluded even in the event of failure of the bearing unit, since the bearing unit is no longer located inside, but radially outside of the flow channel. Another advantage is that by displacing the bearing unit to the outside of the flow channel more free flow cross-section is available in the flow channel to realize the function of the turbine. This allows for a more compact overall design, without restricting the efficiency of the turbine.

The storage unit is water lubricated. The use of water as a lubricant compared to the known from the prior art oil or grease-based lubricants already minimally minimized contamination risk of the turbine flowing through the water is further reduced.

Furthermore, the storage unit has a water inlet, which is fluid-conductively connected to a dedicated water reservoir. The water reservoir preferably contains filtered river water. Preferably, a filter unit is arranged in the inlet to the water reservoir and / or between the water reservoir and the water inlet to the storage unit in order to free the water as much as possible of solids before entering the storage unit.

The invention is advantageously further developed in that the bearing unit has at least one thrust bearing, preferably two thrust bearings, and at least one radial bearing, preferably two radial bearings. Preferably, all bearing surfaces are located radially outside the flow channel with respect to the axis of rotation.

In a particularly preferred embodiment of the invention, the at least one thrust bearing and / or the at least one radial bearing are designed as slide bearings. The Design as a plain bearing is made possible by the reduction of surface pressure, which goes along with the laying of the bearing radially outward of the flow channel.

By using plain bearings a structurally simpler design with fewer components compared to known water turbines is achieved. Sliding bearings reliably take over their bearing function at the high peripheral speeds which occur in the case of the bearing surfaces arranged radially outside the flow chamber.

In a further preferred embodiment, the bearing unit has two outer bearing rings spaced apart in the direction of the axis of rotation. The outer bearing rings preferably take in the assembled state, the rotor unit between them.

The outer bearing rings preferably have mutually facing axial bearing outer surfaces, and the rotor unit has correspondingly formed, oppositely disposed axial bearing inner surfaces for forming the axial bearings. By appropriate positioning of the two outer bearing rings can be in this way on both sides of the rotor unit, the axial play of the bearing unit factory set very precisely, which in turn reduces the susceptibility to wear. Preferably, the two outer bearing rings are designed as identical components, which reduces the component complexity. In a preferred embodiment, the outer bearing rings each have a circumferential radial bearing surface, preferably a radial bearing inner surface, and the rotor unit each has a corresponding, oppositely disposed radial bearing surface, preferably radial bearing outer surface, for forming the radial bearings. While in a water turbine, the forces that must be absorbed in the axial direction, are many times higher than the forces that must be absorbed in the radial direction, a reliable and above all precise radial bearing is still essential. This applies in particular if a gearless, externally excited synchronous generator is to be used for generating electrical energy. In this generator type, only a very small gap is provided between generator rotor and generator stator. Due to the small gap and the high circumferential speeds prevailing due to the large diameter of the generator rotor, a very precise alignment of the generator rotor relative to the generator stator is essential. In addition, in order to achieve the most homogeneous possible stress induction reach, the gap profile during operation of the generator to be as constant as possible. For this purpose, a storage with the least possible radial clearance is required. This is exemplary fulfilled by trained as plain bearings radial bearing. By having the outer bearing rings the radial bearing inner surface, and the rotor unit, the radial bearing outer surface, which rotates as radially outward on the radial bearing inner surface, the radial bearing surface is designed as large as possible. This reduces the surface pressure on the one hand.

In a particularly preferred embodiment of the water turbine, the outer bearing rings on their bearing surfaces on sliding linings. By bearing surfaces here are meant the thrust bearing surfaces and the radial bearing surfaces which have been described above. The sliding linings are preferably arranged in the form of a plurality of, preferably spaced-apart, segments on the respective bearing surfaces.

The sliding linings are preferably formed from elastomers or duromers. The division of the sliding linings into a plurality of segments on the one hand enables the formation of lubricant pads in the spaces between the segments, and on the other hand, the replacement of only those segments that are damaged, while other segments do not need to be replaced.

In a further preferred embodiment, the turbine rotor has a plurality of turbine blades, preferably two, three, four or more. The turbine blades are preferably mounted rotatably on the rotor unit essentially perpendicular to the axis of rotation for adjusting their blade angle. The advantages of a blade angle adjustment in the turbine blades are in particular the Regelverhaltend the power plant. If a water turbine according to the embodiments described above in a hydropower plant is used, in the adjacent to the turbine rotor a nozzle is arranged, the process of power generation can be influenced by a triple control, which consists of a speed regulation, an impeller adjustment by adjusting the blade angle, as well a regulation of the flow cross-section over the distributor. Such a regulation has proven to be advantageous for fluctuating water levels or large fall height change in hydroelectric power plants.

The turbine blades are preferably received by means of a moment bearing in a rotor ring having an inner wall bounding the flow channel. The invention solves their underlying task further by a Hydroelectric plant according to claim 13, which has a turbine according to one of the preferred embodiments described above.

The invention will be described in more detail below with reference to the attached figures with reference to a preferred embodiment. Hereby show:

Figure 1 is a schematic representation of a hydroelectric power plant with a

Hydro turbine according to a preferred embodiment,

FIG. 2 shows a partial view of the turbine from FIG. 1,

Figure 3 is a further partial view of the turbine according to Figures 1 and 2, and

FIG. 4 shows a schematic spatial representation of an outer bearing ring of the turbine according to FIGS. 1 to 3.

FIG. 1 shows a water turbine 1 1, in particular an axial turbine, of a hydroelectric power plant 1, shown partially in cross section. The water turbine 1 1 has a flow channel 12 with a flow inlet 13 and a flow outlet 15. Inside the flow channel 12, a turbine rotor 17 is arranged, which is rotatably mounted about a rotation axis X.

The water turbine 1 1 has a hub shell 19, in which a plurality of turbine blades 21a-d are rotatably mounted. From a radial outer end opposite the hub shell, the turbine blades 21a-d are non-rotatably coupled to a generator rotor 25. The generator rotor 25 is in the present embodiment, an internal rotor which rotates in a generator stator 27. The generator rotor 25 and the generator stator 27 form a, preferably designed as a third-excited synchronous generator, the generator 23. The generator 23 is a gearless ring generator.

Adjacent, in the present embodiment downstream, to the turbine rotor 17, a nozzle 29 is disposed in the flow channel 12. The distributor 29 is set up to adjust or regulate the free flow cross section of the flow channel 12 by means of a plurality of adjustable guide vanes. Further details of the water turbine 1 1 are shown in Figure 2. The water turbine 1 1 is bordered by a bearing unit comprising a first outer bearing ring 31a and a second outer bearing ring 31b. The outer bearing rings 31 a, b form a radially outside of the flow channel 12 arranged outer bearing for the turbine rotor 17th

The turbine rotor 17 and the generator rotor 27 are connected to a rotor unit 35 which is supported by the outer bearing rings 31 a, 31 b.

The turbine blades 21a-d are rotatably received in a turbine ring 33, the inner wall of which preferably merges flush into the wall of the non-rotating flow channel 12.

The reception of the turbine blades and the mounting of the rotor unit 35 is shown in FIG. 3, which shows an enlarged section from FIG. Shown is an example of the inclusion of the turbine blade 21d, the illustration applies by way of example for all other turbine blades. The turbine blade 21d is rotatably supported in the turbine ring 33 by means of a moment bearing 37. A static seal 14 is provided for sealing against fluid transfer from and into the flow channel 12.

The rotor unit 35 has a first axial bearing surface 39a. Opposite the first thrust bearing surface 39a, a first thrust bearing surface 41a of the first outer race 31a is provided. On the first axial bearing surface 41a of the first outer bearing ring 31a, a first sliding coating 43a is arranged.

A mechanically adjustable axial seal 45a is arranged radially inside the bearing surfaces 39a, 41a for sealing against fluid leakage from the outer bearing.

The first outer bearing ring 31a has a first radial bearing surface 47a. Opposite to the first radial bearing surface 47a, a corresponding first radial bearing surface 49a is formed on the rotor unit 35. On the first radial bearing surface 47a of the first outer bearing ring 31a, a sliding coating 51a is arranged.

Radially outside the radial bearing surfaces 47a, 49a, a further seal 53a, preferably identical to the seal 45a, is arranged in order to prevent fluid leakage from the outer bearing. The rotor unit 35 further includes a second thrust bearing surface 39b. Opposite the second axial bearing surface 39b, a second axial bearing surface 41b of the second outer bearing ring 31b is provided. On the second axial bearing surface 41 b of the second outer bearing ring 31 b, a sliding coating 43 b is arranged. A mechanically adjustable axial seal 45b is arranged radially inside the bearing surfaces 39b, 41b for sealing against fluid leakage from the outer bearing.

The second outer bearing ring 31 b has a second radial bearing surface 47 b. Opposite to the second radial bearing surface 47b, a corresponding radial bearing surface 49b is formed on the rotor unit 35. On the second radial bearing surface 47 b of the second outer bearing ring 31 b, a sliding coating 51 b is arranged.

Radially outside the radial bearing surfaces 47b, 49b, a further seal 53b, preferably identical to the seal 45b, is arranged in order to prevent fluid leakage from the bearing.

The outer bearing formed by the bearing rings 31 a, b outer passage has passage bores 55 a, b as fluid inlets or fluid outlets for introducing and discharging lubricant in the bearing interior, with particular preference water is used as a lubricant, in particular filtered river water. The water is preferably provided in a water reservoir 57. A filter unit 59 is optionally upstream and / or downstream of the water reservoir. In FIG. 4, the design of the outer bearing ring 31a, b according to FIG. 3 is shown by way of example. The outer bearing ring 31a, b has on the radial bearing surface 47a, b on a plurality of Gleitbelags segments, which together form the sliding coating 51a, b. The axial bearing surface 41a, b also has a large number of sliding lining segments which jointly form the sliding lining 43a, b. The outer bearing rings 31a, b can be preassembled in an advantageous manner already ex works the one outer bearing ring 31a, b followed by the rotor unit 35 and finally the second outer bearing ring 31b allows easy mounting in the hydropower plant 1. The high number of segments of the sliding linings 51a, b and 43a, b provides in connection with the large diameter of the bearing surfaces 41a , b and 47a, b for a low surface pressure and high wear resistance of the entire plain bearing.

Claims

claims

1. Water turbine (1 1) for a hydroelectric power plant (1), with

a flow channel (12) having a flow inlet (13) and a flow inlet (15),

a turbine rotor (17) arranged in the flow channel (12) with an axis of rotation (X),

a ring generator for generating electrical energy with a generator rotor (25) and a generator stator (27), wherein the generator rotor (25) with the turbine rotor (17) to a rotor unit (35) is rotatably connected, and

a bearing unit (31 a, b) for receiving the radial and axial forces acting on the rotor unit,

wherein the bearing unit is arranged radially outside the flow channel (12) with respect to the axis of rotation (X),

characterized in that the storage unit is water lubricated,

wherein the storage unit comprises a water inlet (55a) fluidly connected to a dedicated water reservoir (57).

2. Water turbine (1 1) according to claim 1,

wherein the bearing unit has at least one thrust bearing, preferably two thrust bearings, and at least one radial bearing, preferably two radial bearings.

3. water turbine (1 1) according to claim 3,

wherein all bearing surfaces with respect to the axis of rotation radially outside the flow channel (12).

4. Water turbine (1 1) according to claim 2 or 3,

wherein the at least one thrust bearing and / or the at least one radial bearing is designed as a sliding bearing.

5. water turbine (1 1) according to any one of the preceding claims,

wherein the bearing unit comprises two outer bearing rings spaced apart in the direction of the axis of rotation (X).

6. Water turbine (1 1) according to claim 5,

wherein the outer bearing rings facing each other have thrust bearing outer surfaces, and the rotor unit has correspondingly formed, oppositely disposed thrust bearing inner surfaces for forming the thrust bearings.

7. water turbine (1 1) according to claim 5 or 6,

wherein the outer bearing rings each have a circumferential radial bearing surface, preferably a radial bearing inner surface, and the rotor unit each having a correspondingly formed, oppositely disposed radial bearing surface, preferably radial bearing outer surface, for forming the radial bearing.

8. Water turbine (1 1) according to claim 6 or 7,

wherein the outer bearing rings have on their bearing surfaces sliding linings.

9. water turbine (1 1) according to claim 6,

wherein the sliding linings are arranged in the form of a plurality of, preferably spaced-apart, segments on the respective bearing surfaces.

10. Water turbine (1 1) according to one of the preceding claims,

wherein the turbine rotor (17) comprises a plurality of turbine blades (21a-d), preferably two, three, four or more, and

wherein the turbine blades (21a-d) are mounted rotatably on the rotor unit (35) substantially perpendicular to the rotation axis X for adjusting its blade angle.

1 1. Hydroelectric power plant (1), with

a water flow through flow channel (12),

a water turbine (1 1) connected to a generator (23) for generating electrical energy and a nozzle (29) located downstream or upstream adjacent to the water turbine,

wherein the water turbine (1 1) is designed according to one of the preceding claims.