GB2249144A

GB2249144A - Turbine for oscillating fluid flow systems

Info

Publication number: GB2249144A
Application number: GB9022932A
Authority: GB
Inventors: Roland Store
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-10-22
Filing date: 1990-10-22
Publication date: 1992-04-29
Also published as: GB9022932D0

Abstract

A turbine is provided that produces a uni-directional rotational output in response to an oscillating axial fluid flow. The turbine rotor includes blades i which each has a leading edge curled over portion forming a concave channel extending from an outer extremity to a point short of the root of the blade. <IMAGE>

Description

TURBINE FOR OSCIlItATING FLUID FLGi SYSTEMS This invention relates to a turbine, which is responsive to an axial fluid flow, and in particular the proposed turbine provides a continuous uni-directional rotational output in oscillating fluid flow systems, where the flow is subject to a repetive reversal in an axial direction with respect to the turbine.

A rarticurar application of oscillating fluid frow systems occurs in vave energy devices where energy can be derived as a result of the undulating movement of the sea surface. Turbines are knawn, which achieve the same end result as the present invention, however the present invention differs significantly from previous turbines in respect of variations in form and method of operation.

According to the present invention, there is provided a driveshaft and hub from which any suitable number of blades either planar or embodying slight curvature are positioned; the blades are equispaced radially with respect to the axis of rotation of the driveshaft in such a way that each successive blade adopts an angle of inclination with respect to the plane of rotation of the turbine comparable to the inclination or pitch of the blades of a fan or ship's propellor; however in the Dresent invention, when observed from the side, each blade diverges by a given acute angle from the plane of rotation so that when an axial fluid ftot impinges on the surface of each blade, the fluid will tend to flow not only to the rear edge of each blade but also towards the outer extremity of each blade.Induced rotation of the turbine defines the leading edge of each blade from which the blade material is formed into a rounded shape comparable to the leading edge of an aircraft wing, however this rounded surface curls round and under for a short distance then terminates, so that with respect to the reverse side of each blade there is a concave channel extending from the outermost part of the leading edge of each blade towards the root of the blade. On account of the aforementioned inclination of the blades with respect to the plane of rotation, fluid impinging on the reverse side of the blades will tend to flow towards the leading edge channel and along the channel towards the root of the brad, where the concave channel ends prematurely, allowing the moving fluid to escape in an axial direction adjacent to the driveshaft.Part of the blade surface between the innermost end of the leading edge channel and the blade root is cut back to facilitate escape of the fluid leaving the channel.

Reactive forces arising from both directions of axial flow result in uni-directional rotation of the turbine.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 is a side view of the turbine.

Figure 2 is a plan view of the turbine seen in the direction indicated by arrow A.

Figure 3 is a side view showing in section the mounting arrangement of the turbine onto a driveshaft.

Cith reference to Fig 1 and Fig 2 the shape of the turbine 1 is illustrated by way of example, comprising a number of planar or slightly curved fan-like blades culminating at each leading edge in a rounded lip, which forms a concave channel relative to the reverse side of each blade so that the channel formed extends from the outer extremity of each blade to a point some distance short of the root of the blade. The turbine 1 would be formed from a suitable material such as stainless steel or aluminium-bronze or other material to comply with the aforementioned description of the turbine shape; Referring to the drawing and Fig 3 in particular, the mounting of the turbine 1 onto a driveshaft 3 is shown by way of example.

A hole in the centre of the turbine structure locates onto a central boss which is part of component 2, which is an integral part of driveshaft 3. The central region of the turbine is sandwiched between the flange of component 2 and ring plate 4 and the whole assembly is secured by bolts and lock-nuts equispaced around the aforementioned flange. Referring to Fig 3, the extension of driveshaft 3 beyond ring plate 4 is optional and is omitted in Fig 1.

The turbine may be designed for either clockwise or anti-clockwise rotation and preferably should conform to the natural tendency of vortex formation, which is anti- clockwise in the northern hemisphere and clockwise in the southern hemisphere.

Claims

1 A turbine, that provides a uni-directional rotational output in response to an oscillating axial fluid flow, described with reference to a disc which is coincident with a reference plane and a central perpendicular axis of rotation, comprises a multiplicity of equi-spaced radial blades formed from the disc with each blade incorporating a pitch angle in accordance with standard practice, however as a distinguishing feature the outermost extremity of each blade is raised up above the reference plane by an equal given amount and as a further distinguishing feature with reference to the concave aspect of the interior form of the turbine there is formed on each blade a leading edge scroll, which emerges from the lowermost edge of each inclined blade and which curls upward and round into the concave interior of the turbine, whilst extending radially from the tip to the root of each blade.

2 A turbine, that provides a uni-directional rotational output in response to an oscillating axial fluid flow, as claimed in Claim 1, incorporates means for freely releasing the inwardly directed radial fluid flow from the vicinity of the leading edge scroll into the area adjacent to the turbine axis.

3 A turbine, that provides a uni-directional rotational output in response to an oscillating axial fluid flow as claimed in Claim 1 or Claim 2, incorporates a fixed mounting onto a circular flange, which is an integral part of a central perpendicular axial driveshaft coincident with the axis of the turbine.

4 A turbine, that provides a uni-directional rotational output in response to an oscillating axial fluid flow, substantially as described herein with reference to Figures 1-3 of the accompanying drawing.