A SINGLE OR MULTI-BLADED ROTOR

Abstract: A single or multi-bladed rotor for use with a fluid flow generator or reactor, the rotor comprising a central hub (12) which is adapted to be mounted to a rotatable shaft, the rotor further comprises at least one radial blade (11) mounted at one end to the hub, wherein the at least one blade has a fluid reactive face (14) which has the configuration of a logarithmic curve substantially conforming to the golden section, i.e. the order of growth of the radius of the curve which is measured at equiangular radii is constant and conforms to the ratio of 5:8.

Description: A Single or Multi-Bladed Rotor Field of the invention This invention relates to a rotor and in particular a single or multi-bladed rotor. The rotor according to the invention may be one which is intended to induce a fluid flow or alternatively may be one which is intended to be influenced by a fluid flow, resulting in rotation of the rotor as a result of that influence. Examples of the application of the rotor according to the invention comprise use as a: fan blade which is used to generate an air flow; a turbine blade which is used to generate a fluid flow, an impeller for use in a pump or compressor, or one which is reactive to a fluid flow; or a propeller which may be used with watercraft and aircraft. Background art The invention comprises a development of the rotor which is disclosed in Australian Patent 694679 (AU-B-62946/96) which comprises a rotor which has a configuration which conforms generally to the curve of a logarithmic configuration substantially conforming to an equiangular spiral of the Golden Section which is also known as the Phi ratio. The content of Australian patent 694679 is incorporated herein by reference. Rotors such as impellors, propellers turbine blades and fan blades have scarcely changed over the years and are relatively inefficient. In addition, it is a common characteristic of such fan blades that their use results in the generation of a considerable amount of noise and in a fluid flow from the rotor which is turbulent. Furthermore, where rotors are used in a liquid environment, if the rotors are caused to rotate too fast, this can result in cavitation on the surface and tips of the rotor which not only reduces the operational efficiency of the rotor but can result in destructive influences on the rotor and the surrounding housing associated with the rotor. It is an object of this invention to provide a single or multi-bladed rotor which can react to or induce a fluid flow and whereby the usage of that rotor results in a reduction of the degree of extraneous turbulence and tip vortices exerted on the fluid in its passage past the rotor with the resultant energy loss and noise generation when compared to conventional rotors which are currently in use. Disclosure of the Invention Accordingly, the invention resides in a single or multi-bladed rotor for use with a fluid flow generator or reactor, said rotor comprising a central hub which is adapted to be mounted to a rotatable shaft, the rotor further comprises at least one radial blade mounted at one end to the hub, said blade having a fluid reactive face which has the configuration of at least one logarithmic curve substantially conforming to the Golden Section. Throughout this specification, the term "fluid reactive face" is be taken as comprising the face of the blade of a rotor which is intended to generate a fluid flow as a result of its rotation around the axis of rotation of the rotor or alternatively be responsive to a fluid flow past the rotor. According to a preferred feature of the invention one blade is mounted to the hub and the hub is provided with a counterweight positioned to balance the rotor in use. According to a preferred feature of the invention at least two blades are mounted to the hub said blades being spaced angularly equidistant around the hub, According to a preferred feature of the invention, the face of the at least one blade remote from the reactive face also has the configuration of a logarithmic curve substantially conforming to the Golden Section. According to one preferred embodiment, the curvature of reactive face and remote face are of a substantially equivalent form. According to a further preferred feature of the invention, the curvature of the reactive surface is uni-dimenεional. According to one embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the axis. According to another embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially tangential to the rotation path about said axis. According to another embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially coaxial with or substantially parallel with said axis. According to a further preferred feature of the invention, the curvature of the reactive surface is bi-dimensional. According to one embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the rotation path of that point about said axis and an axis which is substantially tangential to the rotation path about said axis. According to another embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the axis and an axis which is substantially coaxial with or substantially parallel with said axis. According to another embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially tangential to the rotation path about said axis and an axis which is substantially coaxial with or substantially parallel with said axis. According to a further preferred feature of the invention, the curvature of the reactive surface is three dimensional. According to one embodiment the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the rotation path, an axis which is substantially tangential to the rotation path about said axis and an axis which is substantially coaxial with or substantially parallel with said axis. According to a further preferred feature of the invention, the trailing and leading edge of the rotor have a curvature corresponding to a logarithmic curve conforming to the Golden Section. According to a particular embodiment of the invention, the rotor comprises a three bladed rotor. According a preferred feature of the invention, the rotor comprises a fan blade which is intended to induce or react to a gaseous flow past the rotor. According to an alternative embodiment of the invention, the rotor comprises an aircraft propeller. According to an alternative embodiment of the invention, the rotor comprises a watercraft propeller. According to an alternative embodiment of the invention, the rotor comprises a pump rotor. According to an alternative embodiment of the invention, the rotor comprises a turbine rotor. According to an alternative embodiment of the invention, the rotor comprises a mixer rotor. The invention will be more fully understood in the light of the following description of several specific embodiments. Brief Description of the Drawings The description is made with reference to the accompanying drawings of which: Figure 1 is an isometric view of a rotor according to the first embodiment with the convex face uppermost; Figure 2 is a plan view of the rotor according to the first embodiment in which the convex face of the rotor is uppermost; Figure 3 is an inverted view of the rotor according to the first embodiment as shown at Figure 2; Figure 4 is a side elevation of the rotor according to the first embodiment; Figure 5 is a sectional view along the line 5-5 of Figure 2; Figure 6 is a schematic isometric view of the first embodiment illustrating the fluid flow that it is believed is generated by the rotation of the rotor; and Fig 7 is a graphical illustration of the performance of the rotor of the first embodiment when compared to the performance of a widely marketed conventional domestic exhaust fan blade. Detailed Description of Several Embodiments The first embodiment shown in the drawings comprises a rotor which can be utilised as a fan blade in order to induce an air flow and in particular which can be used as the fan blade of an exhaust fan. As shown in the drawings, the rotor comprises a hub (12) which supports a set of three radial blades (11). The hub (12) is formed with a central aperture (13) which is adapted to be mounted to a rotatable shaft which comprises, in the case of a fan blade intended to induce fluid flow, a drive shaft driven from a suitable motor. Each of the blades are formed with an internal reactive face (14) which is of a concave configuration and which has a three dimensional curvature whereby the curvature in each dimension is about an axis which is radial to the central axis of the rotor, an axis which is tangential to the central axis of the rotor and an axis which is coincidental or parallel to the central axis of the rotor. In each case the curvature is in accordance with a logarithmic curve conforming to the Golden Section. As a result, the blades (11) jointly define a generally concave face of the rotor. In addition, each blade has a remote reactive face (15) which is remote from the reactive face (14) and which also has a three dimensional curvature of a convex nature whereby the curvature in each dimension conforms with a logarithmic curve according to the Golden Section, and whereby the curvature in each dimension is of the same form as the curvature of the reactive face (14) in each dimension. As a result, the remote faces (15) jointly define a generally convex surface of the rotor. Each blade (11) is formed with a pair of generally radial edges (16) and (17) which due to the curvature of the blade are of differing lengths whereby one edge (16) has a greater length than the other edge (17). In addition, each edge has a curvature which conforms to a logarithmic curve conforming to the Golden Section. The fan blade according to the first embodiment is intended to be used in an exhaust fan to induce a flow of air from one space to another whereby with rotation of the fan blade such that the one edge (16) forms the leading edge of each blade, fluid flow will be induced past the fan blade from the convex face to the concave face. Because of the curvature of the reactive face of each of the radial blades of the embodiment, the fan blade induces a vortical fluid flow in the air both as it approaches the fan blade and as it exhausts from the fan blade as illustrated at Figure 6. It has been found that in use of the first embodiment the rotation of the rotor generates a fluid flow through the rotor in which the flowing fluid maintains its own inertia and if the rotor is stopped the fluid flow will continue through the rotor for a period of time because of such inertia. It is believed that this is at least in part due to the circumstance that the use of the rotor of the first embodiment results in the generation of a fluid flow in which the pathway for the fluid flow though the rotor (as distinct from conventional rotors) is constant in its geometry from a position in advance of the entry to the rotor to a position beyond the exit from the rotor. Examples of the First Embodiment A. An example of a fan blade according to the first embodiment has been constructed and used to replace the existing blade of an exhaust fan marketed under the name NUTONE by Nortec Inc. (exhaust fan model 686). The existing fan blade of that exhaust fan comprises a five bladed fan where the blades have a conventional configuration. The exhaust fan incorporating the existing fan blade was tested both with and without flow straightening means which was provided with the fan. In addition, the exhaust fan was modified by replacing the existing fan blade with a fan blade according to the embodiment and the modified exhaust fan was tested both with and without the conventional flow straightener. Figure 7 illustrates the performance of each of the fan blades in a graphical form where the efficiency of the conventional exhaust fan and the modified exhaust fan is plotted against the volume flow rate generated by each exhaust fan where measures of the efficiency of the fan and the flow rate were determined at 2000 rpm, 3000 rpm, 3250 rpm and 4000 rpm. As a result of utilisation of the rotor according to the first embodiment, the efficiency of the fan was increased significantly and the flow rate generated from the fan also increased dramatically. B. In addition, a fan blade according to the first embodiment was utilised in an automotive cooling fan marketed under the name "Davies, Craig" by a company named Davies, Craig (model DCSL 10) as a result the following figures were determined. A second embodiment of the invention comprises a rotor of a similar form to that of the first embodiment where the other edge (17) comprises the leading edge of the rotor which is caused to rotate in the opposite direction to the rotor of the first embodiment. A third embodiment of the invention comprises a rotor of a similar form to that of the first embodiment which is used as a propeller for use with watercraft. It is envisaged that the use of the third embodiment will enable the elimination or at least a reduction in the need for a surrounding shroud or duct which is often required with conventional propellers to improve their performance. According to a fourth embodiment of the invention a rotor of a similar form to that of the first embodiment is used as the impeller of a fluid mixer. According to a fifth embodiment of the invention a rotor of a similar form to that of the first embodiment is used as the impeller of a fluid pump. According to a sixth embodiment of the invention a rotor of a similar form to that of the first embodiment is used as the impeller of a compressor. According to a seventh embodiment of the invention a rotor of a similar form to that of the first embodiment is used as the turbine blade of a turbine. Throughout this specification (including the claims if present), unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiment described above.

Claims: Claims The claims defining the invention are as follows: 1. A single or multi-bladed rotor for use with a fluid flow generator or reactor, said rotor comprising a central hub which is adapted to be mounted to a rotatable shaft, the rotor further comprises at least one radial blade mounted at one end to the hub, said at least one blade having a fluid reactive face which has the configuration of at least one logarithmic curve substantially conforming to the Golden Section. 2. A single bladed rotor as claimed at claim 1 wherein the one blade is mounted to the hub and the hub is provided with a counterweight positioned to balance the rotor in use. 3. A multi-bladed rotor as claimed at claim 1 wherein at least two blades are mounted to the hub said blades being spaced angularly equidistant around the hub, 4. A single or multi-bladed rotor as claimed at any one of the preceding claims wherein the face of the at least one blade remote from the reactive face also has the configuration of a logarithmic curve substantially conforming to the Golden Section. 5. A single or multi-bladed rotor as claimed at claim 4 wherein the curvature of reactive face and remote face are of a substantially equivalent form. 6. A single or multi-bladed rotor as claimed at any one of the preceding claims the curvature of the reactive surface is uni-dimensional. 7. A single or multi-bladed rotor as claimed at claim 6 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the axis. 8. A single or multi-bladed rotor as claimed at claim 6 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially tangential to the rotation path about said axis. 9. A single or multi-bladed rotor as claimed at claim 6 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially coaxial with or substantially parallel with said axis. 10. A single or multi-bladed rotor as claimed at any one of claims 1 to 5 wherein the curvature of the reactive surface is bi-dimensional. 11. A single or multi-bladed rotor as claimed at claim 10 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the rotation path of that point about said axis and an axis which is substantially tangential to the rotation path about said axis. 12. A single or multi-bladed rotor as claimed at claim 10 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially radial to the axis and an axis which is substantially coaxial with or substantially parallel with said axis. 13. A single or multi-bladed rotor as claimed at claim 10 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis which is substantially tangential to the rotation path about said axis and an axis which is substantially coaxial with or substantially parallel with said axis. 14. A single or multi-bladed rotor as claimed at any one of claims 1 to 5 wherein the curvature of the reactive surface is three dimensional. 15. A single or multi-bladed rotor as claimed at claim 14 wherein the curvature of the blades according to the logarithmic curve substantially conforming to the Golden Section is about an axis an axis which is substantially radial to the rotation path, an said axis which is substantially tangential to the rotation path about said axis and an axis which is substantially coaxial with or substantially parallel with said axis. 16. A single or multi-bladed rotor as claimed at any one of the preceding claims wherein the trailing and leading edge of the rotor have a curvature corresponding to a logarithmic curve conforming to the Golden Section. 17. A single or multi-bladed rotor as claimed at any one of claims 1 to 15 wherein the trailing edge of the rotor has a curvature corresponding to a logarithmic curve conforming to the Golden Section. 18. A single or multi-bladed rotor as claimed at any one of claims 1 to 15 wherein the leading edge of the rotor has a curvature corresponding to a logarithmic curve conforming to the Golden Section. 19. A multi-bladed rotor as claimed at any one of the preceding claims wherein the rotor comprises a three bladed. 20. A single or multi-bladed rotor as claimed at any one of the preceding claims wherein the rotor comprises a fan blade which is intended to induce or react to a gaseous flow past the rotor. 21. A single or multi-bladed rotor as claimed at any one of claims 1 to 19 wherein, the rotor comprises an aircraft propeller. 22. A single or multi-bladed rotor as claimed at any one of claims 1 to 19 wherein the rotor comprises a watercraft propeller. 23. A single or multi-bladed rotor as claimed at any one of claims 1 to 19 wherein the rotor comprises a pump rotor. 24. A single or multi-bladed rotor as claimed at any one of claims 1 to 19 wherein the rotor comprises a turbine rotor. 25. A single or multi-bladed rotor as claimed at any one of claims 1 to 19 wherein the rotor comprises a mixer rotor. 26. A single or multi-bladed rotor substantially as herein described.

Inventors: HARMAN JAYDEN DAVID, HARMAN, JAYDEN, DAVID
Applicants: HARMAN JAYDEN DAVID, HARMAN, JAYDEN, DAVID
Application year: 2000
Main classification: F01D5
IPC codes: B63H1, F01D5, F03B3, F03D1, F04D29