GB2440394A

GB2440394A - Turbine rotor

Info

Publication number: GB2440394A
Application number: GB0614629A
Authority: GB
Inventors: Robert Mcewan Tucker
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-07-24
Filing date: 2006-07-24
Publication date: 2008-01-30
Also published as: GB0614629D0

Abstract

A turbine rotor assembly comprising at least one rotor unit including a hub unit 101 mounted for rotation about the longitudinal axis of the hub unit, first and second end plates 103 comprising parallel disks mounted on the hub unit the planes of the end plates being orthogonal to the axis of rotation of the hub unit and at least one rotor blade 102 projecting from the hub unit 101 and extending axially between the end plates and joined thereto, the rotor blade having a cylindrical outer portion 105 and an inwardly directed arcuate portion 104 arranged to be concave to the intended direction of rotation of the rotor unit, the envelope of the rotor assembly being a right circular cylinder. An electricity generating station (eg. utilizing tidal flow) incorporating at least one such rotor assembly is described.

Description

1 2440394 TURBiNE ROTOR ASSEMBLY The present invention relates to

turbine rotor assemblies and more particularly to turbine rotor assemblies for use in water-driven turbines.

Water wheels are a simple form of water-driven turbines and have been known for centuries. Conventionally, they consist of a wheel mounted with its axis of rotation horizontal and with a number of axially flat blades, or buckets, fixed regularly around its periphery. Two types of such waterwheels exist, so-called undershot wheels with which the blades, or paddles as they sometimes are called, dip into a flowing stream of water and over shot wheels with which water is led to the top of the wheels and falls onto the blades, or more commonly, buckets and turn the wheels by means of the weight and potential energy of the water.

Also known are hydro-electric generator sets in which a reaction turbine is mounted with its axis of rotation vertical and has a generator set coipled to the turbine shaft, either directly or via a gearbox.

According to the present invention there is provided a turbine rotor assembly comprising at least one rotor unit including a hub unit mounted for rotation about the longitudinal axis of the hub unit, first and second end plates comprising parallel disks mounted on the hub unit the planes of the end plates being orthogonal to the axis of rotation of the hub unit and at least one rotor blade projecting from the hub unit and extending axially between the end plates and joined thereto, the rotor blade having a cylindrical outer portion and an inwardly directed arcuate portion arranged to be concave to the intended direction of rotation of the rotor unit, the envelope of the rotor assembly being a right circular cylinder.

In the case where the rotor unit incorporates only a single blade, then for the rotor assembly to function continuously, it must include at least two rotor units positioned coaxially with the axially extending edges of adjacent rotor units disposed regularly in azimuth about the peripheries of the end plates of the adjacent rotor units. Thus, if two single bladed rotor units areüsed, the edges of the blades of the rotor units would be separated in azimuth by 180 degrees, if three single bladed rotor units are used, the edges of the blades of the rotor units would be separated in azimuth by 120 degrees and so on.

If a rotor unit has more than one blade, then, similarly, the edges of the blades of the rotor unit are displaced regularly in azimuth, the azimuthal displacement being determined by the number of blades present in the rotor unit. Again, more than one rotor unit can be utilised, with the edges of the blades of each rotor unit being displaced regularly in azimuth with respect to the blades of adjacent rotor units so rotational symmetry is maintained.

A bi-directional rotor unit can be provided by providing each blade with two concave arcuate surfaces separated by a region of cylindrical peripheral surface.

The same rule for the azimuthal displacement of the blades in each and adjacent rotor units, more than one rotor unit is used, applies.

When more than one rotor unit is used, one end plate can be common to two adjacent rotor units.

The peripheiy of one terminal end plate may be provided with a ring gear so as to provide a drive means for one or more electrical generator sets. Alternatively a generator set, or sets, may be coupled to an extension of an axle shaft to which the rotor units are fixed.

According to the invention in a second aspect, there is provided a fluid-powered electricity generating system including at least one turbine rotor assembly as described above coupled to an electricity generating set, or sets.

The invention will now be described, by way of example only, with respect to the accompanying drawings, in which:-Figure 1 depicts cross-sectional views of two rotor units incorporated in a rotor assembly embodying the invention and shows the angular relationship between them.

Figure 2 depicts cross-sectional views of two sets of a second type of rotor unit incorporated in a rotor assembly embodying the invention and shows the angular relationship between them.

Figure 3 depicts cross-sectional views of two sets of a third type of rotor unit incorporated in a rotor assembly embodying the invention and shows the angular relationship between them.

Figure 4 depicts a cross-sectional view of a third type of rotor unit which may be incorporated in a rotor assembly embodying the invention.

Figure 5 shows a plan view of a rotor end unit end plate incorporate in a rotor assembly embodying the invention and which is provided with a peripheral ring gear for transmitting power from the rotor assembly to one or more electricity generating sets and Figure 6 is a view of a conceptual tidal flow electricity generating station embodying the invention.

Referring to Figure 1 of the drawings, there are shown cross-sectional views of two adjacent rotor units 100 which are incorporated into a turbine rotor assembly embodying the invention. As each rotor unit 100 is identical to the other and to other rotor units, if present, of the rotor assembly, corresponding components have the same reference numerals, Each rotor unit 100 consists of an hub unit 101 to which are attached two rotor blades 102 and two end plates 103 in the form of disks of the same diameter, only one of which is shown in each case. In practice, adjacent rotor units 100 share a common end plate 103.

In each rotor unit 100, the rotor blades 102 extend from one end plate 103 to the other and are attached thereto in a fluid-tight manner. Each rotor blade 102 has an arcuate inner portion 104 and an outer cylindrical portion 105 which coincides with the peripheries of the end plates 103, so that the envelope of the rotor assembly is a right cylinder. The inner and outer portions 104,105, respectively, of the rotor blades 102 have joint lines 106. The rotor blades 102 are attached to the hub unit 101 at diametrically opposed positions with the concave surface 107 of one rotor blade 102 facing the convex surface 108 of the other rotor blade 102. The cylindrical outer portion 105 of each rotor blade 102 terminates at a position opposite the position of attachment of the other rotor blade 102 to the hub unit 101 and the joint line 106 between the inner and outer portions 105,106, respectively, of each rotor blade 102 lies opposite to the middle of the distance between the positions at which the rotor blades 102 are attached to the hub unit 101. Successive rotor units are displaced by /2 in azimuth. The hub unit 101 is adapted to rotate about a fixed axle 109, but it could be fixed to an axle which rotates in suitable bearings, if so desired.

Figure 2 shows a second form of rotor unit embodying the invention, those features which correspond with similar features of the rotor unit 100 described with reference to Figure 1 have the same reference numerals. Referring to Figure 2, whereas the rotor blades 102 of the first embodiment of the invention are constructed of plate material, those of the second embodiment of the invention have considerable thickness with a concave surface 107 which 2d extends from the termination of the cylindrical outer portion 105 to the hub unit 10! aproximately at the position of attachment of the other rotor blade 102.

The concave surfaces 107 may be pierced with holes so that when the rotor units 100 are used as components of a water-powered turbine, the spaces 201 between the concave and convex surfaces 107,108 can fill with water so as to increase the mass of the rotor blades 102 and hence there flywheel effect.

Alternatively, the spaces 201 can be filled with a rigid, buoyant material, or they can be left empty, but sealed.

Figure 3 shows a third form of rotor unit 100 which can be rotated in either direction, thus enabling advantage to be taken of both the flood and ebb of the tide of the rotor unit 100 is incorporated in a tidal power generation system.

Again, those components which correspond with similar features of other rotor units embodying the invention have the same reference numerals. Referring to Figure -3, in this case, the rotor blades 102 have Iwo concave inner portions 301,302 with a cylindrical portion outer 303 between them and the junctions between the concave inner portions 301,302 and the cylindrical portion 301 are to be* construed as corresponding to the junction 106 between the inner and outer portions 105, 107 of the rotor blades described previously. Again, the spacçs 304 between the concave inner portions 301,302 can be arranged to be filled with a massive or buoyant material.

Figure 4 shows another form of rotor unit in which there is only a single rotor blade. As before, those components which correspond to imilar components of rotor units described previously, have similar reference numerals. A disadvantage of this embodiment of the invention is that whereas those rotor units described previously could be used singly, if so desired, at least two single-bladed rotor units 100 must be used with their rotor blades displaced regularly in azimuth.

Figure 5 shows a terminal rotor unit end plate 401 which is provided with an upstand 402 upon which there is mounted a ring gear 403 which can be used to transmit the motion of the rotor assembly to one or more electricity generating sets, or other forms of machinery. The ring gear is shown as being on the inner side of the upstand 402, but it can be on the outside of the upstand 402, if so desired.

A preferred use for the present invention is as a water-powered electricity generating system. In this case, preferably the rotor assembly consists of a plurality of co-axial contiguous rotor units 100 positioned with their common axis of rotation vertical with electricity generating sets coupled to the ring gear 403. The generator sets may be accommodated in an housing, or building which forms part of a structure such as a promenade, jetty or barrage. Such a system is illustrated, conceptually, in Figure 6.

Referring to Figure 6, a conceptual tidal flow electricity generating station 500 consists of a rotor assembly 501 comprising a nwnber of rotor units 502, as described above, mount on a common shaft 503 which extends through a tower of lattice or other open structure which provides a free passage for water to and from the rotor units 502. The shaft 503 is mounted at its lower end in a sealed bearing assembly which is fixed to the bed of the sea or estuary where the electricity generating station is situated. The upper end of the shaft 503 terminates in an end plate 507 such as that described with reference to Figure5 and which drives a plurality of gear systems 508 to each of which there is coupled an alternator unit 509. The alternators 509 and their drive units 508 are housed in a building 510 which is erected on a platform 511. More than one individual electricity generating station may be situated at a given location and the platform 511 may be common to all the electricity generating stations 500, forming a jetty, promenade or part of a barrage across an estuary.

For convenience, the invention has been described primarily in terms of 2-blaed rotor units 100, but 3-blade rotor units are more effective and even more blades per rotor unit 100 can be used, with the proviso that the blades must be identical in shape and mass and be distributed regularly in azimuth around the hub unitlOl, so that dynamic balance is maintained. Similarly, the static position of the blades of successive rotor units 100 in a rotor assembly should be staggered regularly in azimuth, as described above.

Claims

CLAIMS

I. A turbine rotor assembly comprising at least one rotor unit including a hub unit mounted for rotation about the longitudinal axis of the hub unit, first and second end plates comprising parallel disks mounted on the hub unit the planes of the end plates being orthogonal to the axis of rotation of the hub unit and at least one rotor blade projecting from the hub and extending axially between the end plates and joined thereto, the rotor blade having a cylindrical outer portion and an inwardly directed arcuate portion arranged to be concave to the intended direction of rotation of the rotor unit, the envelope of the rotor assembly being a right circular cylinder.

2. A turbine rotor assembly according to claim I wherein each rotor unit has a plurality of identical rotor blades disposed regularly in azimuth around the axis of rotation of the rotor assembly.

3. A turbine rotor assembly according to claim 2 wherein the thickness of the rotor blades increases with the radial distance from the hub unit the rotor unit.

4. A turbine rotor assembly according to claim 3 wherein the rotor blades are hollow. K)

5. A turbine rotor assembly according to claim 3 wherein the rotor blades are adapted to be filled with a medium other than that from which the rotor blades are made.

6. A turbine rotor assembly according to claim 5 wherein the said medium has a density equalto or less than that of water.

7. A turbine rotor assembly according to any of claims 3 to 6 wherein the rotor blades have two concave portions arranged back-to-back.

8. A turbine rotor assembly according to any preceding claim wherein the rotor assembly comprises a plurality of rotor units arranged to rotate together about the said axis of rotation, the rotor blades of successive rotor units being disposed regularly in azimuth around the common axis of rotation of the rotor units forming the rotor assembly.

9. A turbine rotor assembly according to claim 8 wherein the successive rotor units have an end plate in common.

10. A turbine rotor assembly according to any preceding claim wherein one rotor unit end plate includes a peripheral upstand which is adapted to provide a ring gear by means of which rotary motion can be imparted to another item of apparatus.

11. A turbine rotor assembly according to claim 10 wherein the other item of apparatus is at least one electricity generating set.

12. A fluid-powered electricity generating station including at least one turbine rotor assembly according to any of claims 1 to 10 coupled to at least one electricity generating set.

13. A fluid-powered electricity generating station according to claim 11 adapted to form part ofa jetty or barrage across a river or estuaiy 14. A turbine rotor assembly substantially as hereinbefore described and with reference to Figures 1 to 5 of the accompanying drawings.

15. An electricity generating station substantially as hereinbefore described and with reference to Figure 6 of the accompanying drawings.