GB2474961A

GB2474961A - Turbine with upwind horizontal axis rotor and passive yaw adjustment

Info

Publication number: GB2474961A
Application number: GB1018261A
Authority: GB
Inventors: Harald Dorweiler
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2009-10-28
Filing date: 2010-10-28
Publication date: 2011-05-04
Anticipated expiration: 2030-10-28
Also published as: GB2474961B; DE102009051117A1; GB201018261D0; DE102009051117B4

Abstract

A turbine, eg a tidal, river or wind turbine, comprises a nacelle 1 mounted on a supporting structure, eg tower 2, by means of an azimuth swivel 3 for rotational movement around a vertical yaw axis 27. A horizontal axis upwind rotor 7 is mounted on the nacelle 1 and is spaced from the yaw axis. Passive yaw, ie in which the nacelle 1 and rotor 7 rotate freely around the yaw axis, is achieved in a predetermined angular sector (the "lock-in range") by the rotor blades 8.1, 8.2, 8.3 being swept aft over at least part of their axial length. For example the blades may be straight or sickle-shaped. Within the lock-in range, deviation from the centred position produces a restoring yaw torque. The nacelle land rotor 7 may be brought into the lock-in range either actively by a drive unit, eg a transverse thruster, or passively by a fin (21, figs.4a,4b) articulated on the downwind end of the nacelle and limited by stops (23-26). Yaw rotation of the nacelle 1 may be limited by stops (34,35, figs.4a,4b).

Description

A turbine with horizontal rotor with passive yaw angle adjustment device The invention concerns a turbine with horizontal rotor with passive yaw angle adjustment device, in particular for a submarine power plant for generating tidal energy with the introductory characteristics of claim I. Turbines with horizontal rotor standing freely in a water current without dam structures are known and correspond to the conception provided by wind energy.

Adaptation to the cycle produced by the ebb and flow between two main current directions is necessary to be able to use a generic turbine with horizontal rotor operating on tidal energy. In the easiest case for that purpose, the rotor is provided with bidirectional turbine blades facing the incoming flow. Said blades may present ellipsoid profiles, as disclosed for instance in document WO 2006/1 25959 Al.

Alternately, point-symmetrical profiles with an S-shock have been suggested by document US 2007/0231148 Al. Such a bidirectional rotor, facing the incoming flow, with torsion-proof fixation of the turbine blade on the hub enables a simplified S..

and hence robust plant design. Indeed, the degree of efficiency is reduced compared to a bearing surface profile adapted to only one inflow direction.

Moreover high torsion loads are generated on the turbine blades in particular for the aforementioned pointsymmetrical profile with S-shock, so that said blades must be designed with high structural resistance. S... S. * * . S

* An alternative plant configuration for adaptation to change in the inflow direction sets forth a rotational movement of the individual turbine blades around 180° on the hub of the rotating unit. See for instance document EP for such a pitch angle adjustment mechanism. The pitch angle understands enables, in addition to adaptation to changeable inflow direction, a simplified power control as well as reliable shutdown of the plant in case of overload by screwing in the turbine blades in the vane position. The shortcoming is however the highly expensive construction for realising the rotation mechanism in the area of the foot point of the turbine blades. Moreover, in case of failure of a pitch angle adjustment device the operating situation will become out-of-control, with the possible loss of individual turbine blades. Under those circumstances, in particular due to the poor accessibility of submarine power plants, with even more cumbersome maintenance, an offshore plant will prove ill-advised.

Another way still for adaptation of a generic turbine with horizontal rotor to incoming flow with variable direction consists in the execution of a whole movement of the machine gondola with the rotating unit, so that a rotor can be used with torsion-proof turbine blades and optimised bearing surface profile. If only one change in direction is provided between two main orientations, there is the possibility to pivot the machine gondola on the supporting structure around a horizontal rotational axis. See for instance document GB 2431207. A flow tracking enabling a rotational movement around a vertical in an angular sector of at least 1800 is however preferred. Hereby, the ellipsoid inflow characteristic of a typical tidal current can be used to the full.

For adjusting a determined yaw angle, the machine gondola is fixed to the supporting structure by means of an azimuth swivel to which a vertical rotational axis is associated. When choosing an active tracking it is necessary to integrate a 0 drive unit into the azimuth swivel. Indeed, a regulation and control system must then be provided, for optimising the yaw angle adjustment according to the incoming flow. For that purpose, a maximum power point regulation may be used S...

*:*. for instance.

The shortcoming of the aforementioned actively tracked yaw angle adjustment is the amount of equipment intended for the necessary actuators and sensors as well as the control and regulation systems. Consequently, a device with passive operation is desirable for yaw angle adjustment. In the easiest case, it may be achieved using a downwind rotor which is disadvantageous due to the negative influence of current through the upstream supporting structure with respect to an upwind rotor. When using the concept of a passive yaw angle adjustment for an upwind rotor, it is known to use a transversally stabilising component such as a fin in the downstream section, which is situated downstream of the rotational axis of the azimuth swivel. This concept then requires a large amount of construction work, if the machine gondola extends longitudinally to space the rotor apart upstream of the supporting structure with a view to move it as far as possible from the gust slizing area. This desired lengthening in upstream direction must be compensated for by the transversally stabilising device on the downstream side, so that accordingly large-sized fin and the retaining structures therefore necessary are required.

The object of the invention is then to remedy the aforementioned shortcomings of the state of the art and to offer an upwind rotor with horizontal rotational axis with a device of simplified design for passive yaw angle adjustment. Such a turbine with horizontal rotor with a self-tracking system for the yaw angle must be useable near submarine power plants, in particular tidal power stations, also for wind power stations.

In a further embodiment, the turbine with horizontal rotor must rotate in the optimal S...

yaw angle position independently of the starting position automatically and perform preferably a forward and backward movement in an angular sector of approx. 180° . 4o instead of a full circle movement, to prevent the power cable from twisting between the electrical generator in the machine gondola and the supporting structure by avoiding any repeated full circle rotation. S... S. * * S I

* Starting from a generic hydraulic power plant with a rotor designed as an upwind rotor with a horizontal rotational axis, the inventor has recognised that passive yaw angle adjustment is then permitted if the rotor includes turbine blades with at least one aft-swept section. A rotor with a large number of aft-swept turbine blades is preferred with rectilinear longitudinal axis. Consequently, for the upwind rotor here considered, by aft sweep is meant a deviated rotation of the longitudinal axis of a turbine blade with respect to the radial line, which causes displacement away from the rotor plane towards a parallel plane thereto, which includes the rotational axis of the azimuth swivel.

The aft sweep of the turbine blades of the rotor, with a given angular position between the rotation axis of the rotor and the inflow direction, designated below as angular deviation, generates asymmetrical thrust loads on both lateral halves of the rotor and offsets the associated thrust centres. The result is hence a yaw torque around the axis of the azimuth swivel of the plant, which brings the machine gondola with the rotor back into a position for to parallel orientation of the rotation axis and of the inflow direction, i.e. in the centred position.

The torque resulting from angular deviation and then leading to self-tracking will always be there if the excursion angle with respect to the centred position does not exceed a certain limit angle which defines a lock-in range. Consequently, the extension of the lock-in range depends on the one hand on the currently prevailing incoming flow and on the other hand on the sizing of the plant. Defining the protruding length relevant, i.e. the distance between the rotor plane and the axis of the azimuth swivel, the sweep angle of the turbine blades, the outer diameter of the rotor and the turbine blade profile.

I

I..... * I

Self-centring of the upwind rotor according to the invention gives the possibility of 4o designing the azimuth swivel for achieving connection between the machine I. 1111 * 1 gondola and the supporting structure as a freely rotating large bearing with a *:** certain degree of rotation freedom around the vertical bearing axis. Providing the a...

swept rotor is situated in the lock-in range and positions itself automatically with a rotation axis parallel to the flow, the azimuth swivel need not be actuated. Indeed it is necessary to orient the machine gondola initially in such a way that the rotation axis of the rotor enters the lock-in range. For a first embodiment an activable drive unit is associated with the azimuth swivel, which at the beginning of operation places the plant in the desired basic orientation. Below, the drive unit can release the azimuth swivel and the machine gondola will then rotate together with the rotating rotor through the effect of the self-centring flow. A basic change in direction of incoming flow as well as a gradual change in angle of incoming flow may take with a tidal current. I,

To dispense with a temporarily connectable drive unit requiring a large amount of construction work for the azimuth swivel, the basic orientation of the machine gondola for guiding the rotation axis of the rotor in the lock-in range can be provided by an additional drive unit outside the azimuth swivel, for instance in the form of a transverse thruster. Consequently, the additional drive unit should be spaced apart from the rotational axis of the azimuth swivel and generate a transverse thrust on the machine gondola, with a yaw torque which is sufficiently high.

Another embodiment of the invention provides a system, which also passively triggers the yaw angle tracking up to the lock-in range. To do so, an articulated fin is provided on the machine gondola in a region opposite the rotor with respect to the rotational axis of the azimuth swivel. The fin may carry out a swivel movement around a vertical axle in a swivel range limited by stops on the machine gondola.

In case of a rotor situated in vane position facing an incoming flow against the operating direction, the fin is folded over on one side and pressed against the stop S: I provided to that effect on the machine gondola. A corresponding sizing enables a rotational movement of the machine gondola around the azimuth swivel due to the 40 dynamic pressure applied to the fin until the rotor reaches its upwind rotor position and the self-centring effect according to the invention provides parallel positioning *:* with respect to the incoming flow. S... S. * . S

* The system explained above for guiding the plant into the lock-in range, wherein self-centring takes place, which works exclusively by using the flow forces acting on the plant, may be improved further with a view to carry out a controlled rotation limited to a semi-circle. It is understood below that the rotational movement of the machine gondola around the azimuth swivel on the supporting structure is restricted to a forward and backward movement between the opposite main inflow directions during the ebb and flow of a tidal current and to an adjoining angle variation region adapted to the installation site. A power cable extending from a generator in the machine gondola to the supporting structure is advantageously twisted under controL Consequently, the desired forward and backward movement is imposed by additional stops on the supporting structure, wherein said stops provide an angular setpoint for the fin with respect to the rotation axis and delineate the yawing of the machine gondola.

The invention is described more in detail below using exemplary embodiments and in connection with figure illustrations, wherein the following details are shown: Figure 1 shows a side view of a turbine with horizontal rotor according to the invention.

Figure 2a shows the turbine with horizontal rotor of Figure 1 in elevation view in a position centred relative to the inflow direction.

Figure 2b shows the effective incoming flow and the resulting flow forces on a blade element. * * ***.

Figure 3a shows a view corresponding to Figure 2a with an angle offset between the rotation axis and the inflow direction. *

Figure 3b shows the fixing of a blade element for the operating situation according to Figure 3a. I... S. S * * *

* Figure 4a shows a water power plant according to the invention with a fin fastened to the machine gondola in a swivel fashion for guiding the plant into the lock-in range of the self-centring as a side view.

Figure 4b shows the configuration according to Fig 4a in elevation view with the range of movement of the plant.

Figures -10 show, for a plant corresponding to Figures 4a and 4b in elevation view, the operating mode of a completely passive yaw angle adjustment with a yawing limitation on a semi-circle with an additional angle variation region adapted to the installation site.

Figure 1 is a simplified diagram of a generic turbine with horizontal rotor, of free-standing design without dam structures, in particular for using a tidal current. In this instance, the plant rests on the water bed 5 by means of the foundation 4, which is designed as gravity foundation. A tower supporting structure 2 is erected on said water bed and a machine gondola 1 is placed on said structure. The connection between the supporting structure 2 and the machine gondola 1 is provided by an azimuth swivel 3, which enables a rotational movement of the machine gondola I around a vertical axis, designated below as yaw axis 27.

The bearings intended for the shaft 9 of the rotating unit 6 as well as components of the electrical generator which is driven by the shaft 9, are accommodated in a machine gondola I (details not shown).The major section of the rotating unit 6 is the rotor 7, which predominantly consists of four blades. Further embodiments with an odd number of turbine blades, in particular the application of a three-blade rotor, can be envisioned, wherein the yaw angle can be adjusted automatically, described below, also for such a rotor configuration. According to the invention, the rotor 7 includes turbine blades 8.1, 8.2, 8.3 which are aft swept at least by sections. In the configuration shown on figure 1, the turbine blades 8.1, 8.2, 8.3 have a rectilinear threading line which presents the required aft sweep over its whole longitudinal span. To do so, the threading line connects the profile section points on the profile chords at one quarter of the profile depth. As a result, the rotor plane 12, which is stretched by the centres of the foot points of the turbine blades 8.1, 8.2, 8.3, for the upwind rotor configuration represented upstream of the tip path plane 28 on radially outer ends of the turbine blades 8.1, 8.2, 8.3. The effect produced for passive yaw angle adjustment is represented below in the light of Figures 2a -3b.

Figure 2a shows the plant according to the invention of figure 1 in elevation view. It is a diagrammatic representation of a first lateral thrust force Dl and a second lateral thrust force D2 on the rotating rotor 7, which are applied on the first lateral thrust centre 30 and the second lateral thrust centre 31. In order to determine them, the surface covered by the rotating rotor 7 is split by a vertical sectional plane 29, which is stretched from the rotation axis 14 and the yaw axis 27, and all thrust loads are added vectorially and separately to both sides of the vertical sectional plane 29. The blade element theory can be resorted to determine approximately the thrust loads exerted on the turbine blades 8.1, 8.2, 8.3 designed as buoyant rotors. For that purpose, blade elements 15.1, 15.2, 15.3 oriented on Figure 2a in inflow direction 13, are represented by way of example with a matching radial distance to the to the rotation axis 14.

Figure 2b shows the incoming flow against the middle profile section 16 of the blade element 15.2 of the turbine blade 8.2, whose profile polar curve is resorted to in order to determine the force exerted on the blade element 15.2. For explanation purposes, the following details are shown on Figure 2b: The profile chord 17 includes the blade adjustment angle Wb for the rotation direction 50. The inflow angle Wa of the effective inflow speed Vr results from the vectorial addition of the rotation speed U and the inflow speed Va. The result on the hydrodynamic * * centre 51 of the profile section 16 is the total flow force Fg, which can be broken down vectorially into the tangential force Ft parallel to the rotation direction 50 and *:*.; the vertical thrustforce Es.

Figure 3a shows the rotor 7 with a rotation axis 14, which is offset angularly with respect to the inflow direction 13. Consequently, the first thrust centre 30 and the second thrust centre are displaced with respect to the yaw axis 27, so that a modified leverage effect should be taken into account. For a consideration in volume, it is a diagrammatic representation of a first transverse distance 01 and a second transverse distance Q2 of the thrust centres 30, 31 relative to the plane which is stretched by the yaw axis 27 and the inflow direction 13. In the situation shown on figure 3a, an angular deviation inside the lock-in range produces the resulting yaw torque 18, which acts against the angular deviation and hence brings the rotor 7 back to the centred position shown on figure 2a.

If the blade element theory is again applied for determining the hydrodynamic rotor forces different blade elements are provided on both sides of the vertical sectional plane 29. This is described by way of example in the light of the blade element 15.4 on the turbine blade 8.1 which henceforth presents a reduced effective sweep angle due to the angle offset of the plant, i.e. it is placed steeper against the inflow direction relative to the central position so that on this side the projection radius of the rotor flight circle increases perpendicularly to the incoming flow.

Figure 3b shows an enlargement of the circular area A, in dotted lines, of Figure 3a with the blade element 15.4 on the turbine blade 8.1. The illustrated blade element 15.4 presents profile sectional direction 52 which is oriented parallel to the inflow direction 13. Its curve deviates from the original profile sectional direction 53 (represented in dotted lines),which corresponds to the matching blade element *:::: 15.1 in case of parallel positioning of the rotation axis 14 relative to the flow direction according to Figure 2a. The result is that the profile sectional directions used for applying the blade element theory depend on the angle adjustment between the rotation axis 14 and the inflow direction 13, so that angle-related * * profile cross-sections 16 with different profile polar curves should be taken into *:" account due to the warping and tapering of the turbine blades 8.1, 8.2, 8.3. S. * * S *

* Additionally, the integration of the hydrodynamic forces on the turbine blades 8.1, 8.2, 8. 3 based on the blade element theory should take into account a radial blade element extension dependent on the angular deviation of the rotation axis 14, if an originally selected number of blade elements 15, 15.1, 15.2, 15.3, 15.4 is preserved. This can be obtained from the modification of the projection surface of the turbine blades 8.1, 8.2, 8.3 perpendicular to the inflow direction 13.

In an alternative embodiment of the invention, turbine blades can be envisioned which do not present an aft sweep over their whole longitudinal span.

Consequently, at least the hydrodynamically particularly effective radially external region is preferably provided with the desired sweep. A further embodiment may also be envisioned, for which a first turbine blade section has a radial line geometry and a second turbine blade section presents an aft sweep, wherein the transition between both these sections shows a certain flexibility. This configuration enables to increase the sweep angle of the second turbine blade section in case of overload and hence to reduce the effective diameter of the rotor 7 for restricting the power absorbed from the plant. Furthermore, embodiments (non illustrated in detail) of the invention can be envisioned, such as sickle-shaped turbine blades 8.1, 8.2, 8.3, causing an aft sweep and which are particularly advantageously as regards simplified elimination of foreign bodies on the rotor 7.

Figure 4a shows another embodiment of the invention with an additional passive- acting system for guiding the swept rotor 7 into the lock-in range, wherein self-centring takes place. For that purpose, a fin 21 is articulated on the rear end 33 of the machine gondola 1, which lies opposite the rotor 7 relative to the yaw axis 27.

The fin 21 may carry out a limited rotational movement around a vertical pivot axis 22, wherein, as represented in elevation view on figure 4b, the movement is restricted by a paired symmetrical arrangement a first fin stop 23 rotating therewith 20 and a second fin stop 24 rotating therewith.

S. .*S*

S

In case of wrong incoming flow towards on the rear end 33 of the machine S. S. gondola, such a fin 21 is pressed against the first fin stop 23 rotating therewith or the second fin stop 24 rotating therewith. The dynamic pressure forces generated in succession on the fin 21 rotate the machine gondola 1 with the rotor 7 around the yaw axis 27.

On this basis, a first additional pair of stops is provided in a further embodiment according to figures 4a and 4b namely the first fixed fin stop 25 and the second fixed fin stop 26, which are connected to the supporting structure 2. A third pair of stops, the first gondola stop 34 and the second gondola stop 35, concerns the limited movement of the machine gondola 1. The cooperation of all stops enables to adjust the deflection direction of the fin 21 in such a way that the machine gondola 1 may carry out movements around the yaw axis 27 in a limited angular sector, so that in case of varying inflow direction a substantially forward and backward movement takes place. This ensures that the power cable running via the azimuth swivel 3 is not twisted.

The completely passive yaw angle centring is described below in the light of Figures 5 -10. A tidal power plant according to the invention is based on the assumption of the possibilities of movement illustrated on figure 4b. Consequently the main inflow direction at ebb is 0° and conversely 1800 at high tide for the maximal speed. With respect to both these main inflow directions, the movement range for the yaw angle of the plant, shown by the circular segment 19 of the rotor represented in dotted lines on figure 4b, is enlarged in the area of both main inflow directions by 30°. This range of angle variation depends on the installation site and takes into account angle variations as well as the cycle of a tidal ellipse and can be adapted to the local parameters. The range of yaw movement is determined by * the circular segment 19 of the rotor, wherein a movement is substantially permitted in the third and fourth quadrants, concretely in the angular sector of 150° to 30°.

Both these angular positions mark two end positions, for which the pin 37 fastened * 4o to the machine gondola I abuts on the first gondola stop 34 or on the second gondola stop 35. These are represented in dotted lines on figure 4b. S... a...

The possibility of movement of the fin 21 is limited to the circular segment 20 of the fin, wherein the associated stops, the first fixed fin stop 25 and the second fixed fin stop 26, adopt the angular positions of 190° and 350° for the illustrated embodiment. Consequently, configurations can be adapted to the site of installation, for which the fixed fin stops 25, 26 are closer to 180° and 360°. To do so, the circular segment 20 of the fin lies substantially in the first and second quadrants. Additionally, the derricking angle sector 36 is specified for the fin 21, for describing the limited movements between the first fin stop 23 rotating therewith and the second fin stop 24 rotating therewith.

Figure 5 shows the incoming flow of the rotor 7 for an inflow direction 13.1, which lies at 0° according to the configuration on figure 4b and shows a first main inflow direction at ebb. Figure 6 represents the final phase of the ebb wherein the inflow direction 13.2 is approx. 30° so that the tidal ellipse is predominantly assumed as clockwise rotating. For explanation purposes, the tidal ellipse on the Figures is based on the assumption that the variations in inflow directions are strongly marked, wherein the tidal ellipse is usually designed substantially flatter for a real tidal current. Moreover, due to the symmetrical position of the fixed stop as regards an axis, which runs through the angle of 90° and 270° for the configuration according to Figure 4b, a plant according to the invention can also follow a tidal ellipse with an anticlockwise excursion inflow angle.

For the significantly reduced inflow speed, the braking torques of the plants cannot be overcome for the incoming flow according to Figure 6 and the rotor comes to a standstill. As regards the yaw angle adjustment, the plant remains in the end position due to the bearing friction in the azimuth swivel 3, for which currently a stop from al pair of stops is in contact. Accordingly, the fin 21 abuts against the first fin stop 23 rotating therewith and additionally the first fixed fin stop 25. Additionally, the machine gondola 1 is guided against the second gondola 20 stop 35 which is not shown in detail on figure 6. The end position is however * clearly visible through the circular segment 19 of the rotor illustrated. S. S* * **..

Figure 7 shows an inflow direction 13.3 from approx. 175° for the high tide arriving from the rear on the plant. Accordingly, the rotor 7 faces the wrongly incoming flow at the beginning of the operating mode on figure 7. Due to the approximately angular positioning of the fin 21 with respect to the horizontal, a dynamic pressure is exerted on the fin 21, which is sufficient to rotate the plant around the yaw axis 27, in the inflow direction 13.4 illustrated on figure 8 from 180°, which shows the second main inflow direction in case of high tide. Consequently, the rotational movement triggered by the fin 21 is guided into the Jock-in range for the present inflow direction 13.4, so that the self-centring effect applied to the aft-swept rotor 7 finally positions the plant relative to the inflow direction 13.4. This operating situation with a rotating rotor is represented on figure 9.

The inflow direction is displaced clockwise during the further time sequence of the tidal current. Consequently, the useful angular sector ends at high tide and hence the rotation axis of the rotor 7 for an incoming flow of approx. 210° according to the inflow direction 13.5 shown on figure 10. In such a case, neither the fin 21 nor the machine gondola 1 abuts against one of the aforementioned stops. In the further time sequence of the tide, not illustrated in detail below, the oncoming ebb causes a crossflow on the fin 21, which guides said fin against the second fin stop 24 rotating therewith and brings the plant in the area of the circular segment 19 of the rotor back to the operating position as the flow gains in strength, until the starting position shown on figure 5 is recovered when the inflow direction 13.1 is 0°.

The examples of embodiment discussed for explaining the invention in greater detail relate to tidal power stations. Similarly, the use according to the invention of *:"* a swept rotor for automatical yaw angle adjustment for an upwind rotor in horizontal configuration should not be limited exclusively to this application.

"20 Advantageous uses are also provided for river water power stations or for * obtaining maintenance-free wind power stations. Further embodiments of the invention can be found in the appended protected claims. SS* S. S * . S * S.

List of reference numerals I Machine gondola 2 Supporting structure 3 Azimuth swivel 4 Foundation Water bed 6 Rotating unit 7 Rotor 8.1, 8.2, 8.3 Turbine blade 9 Wave Hub 11 Dome 12 Rotor plane 13,13.1, 13.2, 13.3, . 13.4 Inflow direction *eS.

14 Rotation axis 15.1, 15.2, * . 20 15.3 Blade element * 16 Profile section 17 Profile chord *** *:*.; 18 Resulting yaw torque 19 Circular segment of rotor 20 Circular segment of fin 21 Fin 22 Swivel axis 23 First fin stop rotating therewith 24 Second fin stop rotating therewith 25 First fixed fin stop 26 Second fixed fin stop 27 Yaw axis 28 Tip path plane 29 Vertical sectional plane First lateral thrust centre 31 Second lateral thrust centre 32 Flow cross-sectional plane 33 Rear end 34 Firstgondola stop Second gondola stop 36 Derricking angle sector 37 Pin Rotation direction 51 Hydrodynamic centre 52 Profile sectional direction 53 Original profile sectional direction d Radial blade element extension *::::* Dl First lateral thrustforce D2 Second lateral thrust force Fg Total flow force * 20 Fs Thrust load S...' * Ft Tangential load QI First transverse distance Q2 Second transverse distance U Rotation speed Va Inflow speed Vr Effective inflow speed Wa Inflow angle Wb Blade adjustment angle

Claims

Claims 1. A turbine with horizontal rotor including: 1.1 a supporting structure (2); 1.
2 a machine gondola (1), which is fastened to the supporting structure (2) by means of an azimuth swivel (3) so that the machine gondola may carry out a rotational movement around a substantially vertical yaw axis (27); 1.3 a rotor (7) designed as an upwind rotor, which rotates spaced apart from the yaw axis (27) of the machine gondola (1) and defines a rotation axis (14), wherein the rotor (7) includes turbine blades (8.1, 8.2, 8.3) and a rotor plane (12), which is defined by the foot points of the turbine blades (8.1, 8.2, 8.3) and a tip path plane (28), which is defined by radially outer ends of the turbine blades (8.1, 8.2, 8.3), are allocated to the rotor (7); characterised in that 1.4 at least part of the turbine blades (8.1, 8.2, 8.3) are aft swept, wherein the tip path plane (28) lies between the rotor plane (12) and a plane which accommodates the yaw axis (27) and is perpendicular to the rotation axis (14); and 1.5 the machine gondola is fastened to the supporting structure (2) freely rotating around the yaw axis (27). * *.* * . S...

: 2. A turbine with horizontal rotor according to claim 1, characterised in that all turbine blades (8.1, 8.2, 8.3) of the rotor (7) are aft swept.
3. A turbine with horizontal rotor according to one of the claims 1 or 2, characterised in that all turbine blades (8.1, 8.2, 8.3) of the rotor are aft swept over their whole longitudinal span.
4. A turbine with horizontal rotor according to one of the claims 1 or 2, characterised in that at least a portion of the turbine blades (8.1, 8.2, 8.3) of the rotor (7) present a radially running longitudinal axis in at least one section.
5. A turbine with horizontal rotor according to one of the previous claims, characterised in that the yaw angle of the turbine blades (8.1, 8.2, 8.3), the diameter of the rotor (7) and the distance between the rotor plane (12) and the yaw axis (27) are arranged in such a way that a resulting yaw torque (18), returning the angular deviation, is generated for the angular deviations between the rotation axis (14) and the inflow direction (13), said deviations being comprised in a lock-in range (15).
6. A turbine with horizontal rotor according to one of the previous claims, characterised in that on the rear end (33) of the machine gondola (1), which lies opposite the rotor (7) with respect to the yaw axis (27), a fin (21) is movably mounted with a vertical pivot axis (22), wherein the swivel range is restricted by a paired configuration of I... .* * a first stop (23) and a second stop (24) on the machine gondola (1). ** * * * * * 4% ** a *S * S S...S *5SS S. * S S. * .