WO2005073560A1

WO2005073560A1 - A vortical flow rotor

Info

Publication number: WO2005073560A1
Application number: PCT/AU2005/000117
Authority: WO
Inventors: Jayden David Harman
Original assignee: Pax Scientific, Inc
Priority date: 2004-01-30
Filing date: 2005-01-31
Publication date: 2005-08-11
Also published as: CN1985093A; US20070025846A1; US7488151B2

Abstract

A rotor (31) for use with a fluid flow generator or reactor, said rotor (31) being rotatable about a central axis of the rotor (31) and having a at least one vane (35) arranged, in use, to induce a generally axial fluid-flow into the central axial region of the rotor and an outward flow from the central axial region of the rotor (31) to the outer periphery of the rotor (31), wherein the at least one vane (35) comprises a vortex generator adapted to accelerate the fluid away from the central axis of the rotor (31) in a vortical motion.

Description

A Vortical Flow Rotor

Field of the invention

The present invention relates to a rotor which is intended to induce fluid flow and/or to be influenced by fluid flow and can have relevance to blower fans for moving air, pumps for inducing fluid flow and torque generators which are responsive to fluid flow such as turbines.

Background Art

The inventor has previously disclosed in WO9703291 , which matured into US 5,934,877 and others, 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 U.S. patent 5,934,877 is incorporated herein by reference. It is a feature of the rotors according to that disclosure that they have a surface which defines an arcuate fluid pathway for fluid flow about the central axis about which the rotor is able to rotate.

About half of the world's fan production each year comprises centrifugal blower type fans as opposed to axial type fans. These fans are typically used to provide higher air pressures than axial type fans at a comparably lower flow rate. They tend to be more costly to produce, heavier and require more torque from a drive motor with the resultant reliance on expensive, higher performance motors. They are noisy and inefficient to operate. Good blower efficiency tends to be in the 30% to 40% range according to the blower industry's manner of defining static efficiency.

A substantial percentage of the world's pumps also are centrifugal in nature. In a manner similar to blower fans, such pumps typically have an impeller mounted in a housing which, when rotated, flings fluid centrifugally from the rotor center. The fluid being flung out creates a central low pressure zone, causing the impeller to draw replenishing fluid into its central zone. The blower fan operates in much the same way.

In contrast, the fluid flow found caused by axial fans and pumps is substantially in a direction parallel with the central axis of the rotor.

In general, centrifugal fans and pumps comprise a rotor having a series of vanes (also referred to as blades) in which the fluid is caused to flow in a substantially radially-outward direction away from a central axis about which the rotor rotates. The losses in centrifugal fans and pumps result from turbulence generated by the vanes. In addition, the fluid exhausted by the fan is then conducted to an outlet and further losses are incurred in the flow from the fan to the outlet.

All fluids when moving under the forces of nature tend to move in spirals or vortices. These spirals or vortices generally comply with a mathematical logarithmic progression known as the Golden Section or the Fibonacci Progression. The invention enables fluids to move over the surfaces of the rotor in their naturally preferred way, thereby reducing inefficiencies created through turbulence and friction which are normally found in apparatus commonly used for inducing fluid flow and torque generators which are responsive to fluid flow and as a result reducing the likelihood of wear and reducing energy use and noise generation.

Disclosure of the Invention

Accordingly the invention resides in a rotor for use with a fluid flow generator or reactor, said rotor being rotatable about a central axis of the rotor and having a at least one vane arranged, in use, to induce a generally axial fluid-flow into the central axial region of the rotor and an outward flow from the central axial region of the rotor to the outer periphery of the rotor, wherein the vanes comprise vortex generators adapted to accelerate the fluid away from the central axis of the rotor in a vortical motion. According to a preferred feature of the invention, the outward flow comprises an average flow with a substantial radial component.

According to a preferred feature of the invention, the at least one vane comprises an element which is a vortex generators.

According to a preferred feature of the invention, the at least one vane is configured as a vortex generator.

According to a preferred feature of the invention, each of the at least one vane comprises a surface which has a configuration of a logarithmic curve substantially conforming to the equiangular or Golden Section.

According to a preferred feature of the invention the curvature of the surfaces are transverse or perpendicular to the central axis.

According to a further preferred feature of the invention the curvature of the surfaces can be in a direction parallel to the central axis.

According to a further preferred feature of the invention the curvature of the surfaces are both transverse to the central axis and parallel to the direction of the central axis to define a three dimensional surface conforming to the equiangular or Golden Section.

According to a further preferred feature of the invention the rotor comprises an impeller which is adapted to be driven to rotate about its central axis to induce fluid flow over the surface. According to an alternative preferred feature of the invention the rotor is adapted to be subjected to a fluid flow over said surface to induce a rotation of the rotor about the central axis.

According to a preferred embodiment, the rotor comprises a rotor support in the form of bowl with a profile corresponding to the curve of the vanes to thereby promote vortical flow. According to a further aspect, the invention resides in a centrifugal blower, fan, pump or turbine having a rotor as described above.

According to a further aspect, the invention resides in a centrifugal blower, fan, pump or turbine comprising a body defining a chamber; said chamber having a central axis, an outlet formed at the periphery of the chamber, and an opening formed in a wall which is substantially centrally located relative to the central axis; a rotor rotatably supported in the chamber for rotation about said central axis; a drive shaft concentric with the central axis; said rotor having vanes which extend in a generally outward direction away from the central axis to direct fluid flow across the rotor in a substantially radial flow from the central axial region of the rotor to the outer periphery of the rotor; the surfaces defined by the opposed faces of the vanes being curved wherein the curvature of the surface has the characteristics of a logarithmic curve substantially conforming to the Golden Section and are thereby adapted to induce vortical flow when in use.

According to a further preferred feature of the previous feature the cross-section of the vane generally increases between the inlet and outlet where the variation in cross-section of the vane varies logarithmically in substantial conformity to the Golden Section.

According to a preferred feature of the invention, the rotor is configured to promote or be responsive to flow which has both an axial and a radial component.

According to a preferred embodiment, the housing comprises inlet and outlet ducts configured with active surfaces having a curvature substantially conforming to the equiangular or Golden Section configured to promote vortical fluid flow through the housing.

The invention will be more fully understood in the light of the following description of several specific embodiments. Brϊef Description of the Drawings

The description is made with reference to the accompanying drawing of which:

Figure 1 illustrates the form of the Golden Section;

Figure 2 is an isometric view of a centrifugal fan of conventional design;

Figure 3 is an isometric view of a rotor of the centrifugal fan of Figure 2;

Figure 4 is a plan view of a rotor of the rotor of the centrifugal fan of Figure 2;

Figure 5 is an isometric view of a centrifugal fan according to first embodiment;

Figure 6 is a plan view of the centrifugal fan of Figure 5;

Figure 7 is an exploded view of the centrifugal fan of Figure 5, showing the rotor removed from the housing;

Figure 8 is plan view of the rotor of a centrifugal fan according to a second embodiment;

Figure 9 is an isometric view of the rotor of a centrifugal fan according to a third embodiment;

Figure 10 is an isometric view of the rotor of a centrifugal fan according to a fourth embodiment;

Figure 11 is an isometric view of a centrifugal fan according to a fifth embodiment

Figure 12 is an isometric view of the centrifugal fan according to Figure 12 showing the inlet cowling separated form the fan housing;

Figure 13 is an exploded view of the centrifugal fan according to Figure 12. Detailed description of preferred embodiments

Each of the embodiments is directed to a rotor which can be utilized to generate fluid flow as in the case of a blower fan or pump or which can be responsive to fluid flow to produce a torque as in the case of a turbine or motor. It is a characteristic of each of the embodiments that fluid is caused to flow substantially transversely to the axis of the rotor about which the rotor rotates. Such rotors are of a type generally referred to as centrifugal rotors and centrifugal pumps, centrifugal fans and centrifugal turbines are well known.

As stated previously, all fluids when moving under the influence of the natural forces of Nature tend to move in spirals or vortices. These spirals or vortices generally comply to a three-dimensional mathematical progression known as the Golden Section or the Fibonacci Progression.

Each of the embodiments serves to enable fluids to move in their naturally preferred way, thereby reducing inefficiencies and reducing the noise created through turbulence and friction which are normally found in apparatus commonly used for inducing fluid flow and in torque generators which are responsive to fluid flow. Previously developed technologies have generally been less compliant with natural fluid flow tendencies.

The rotors of each of the embodiments described herein are generally designed in all respects, in accordance with the Golden Section and therefore it is a characteristic of each of the embodiments that the vanes of the rotors of the embodiments provides a fluid pathway which is of a spiralling configuration and which conforms at least generally to the characteristics of the Golden Section.

The characteristics of the Golden Section are illustrated in Figure 1 which illustrates the unfolding of the spiral curve according to the Golden Section. As the spiral unfolds the order of growth of the radius of the curve which is measured at equiangular radii (e.g. E, F, G, H, I and J) is constant. This can be illustrated from the triangular representation of each radius between each sequence which corresponds to the formula of a:b = b:a+b which conforms to the ratio of 1 : 1.61803... and which is consistent through out the curve. It is a characteristic of each of the embodiments that the curvature of the surfaces which form the rotor takes a two dimensional or three dimensional shape and which substantially conform to the characteristics of the Golden Section and that any variation in cross-sectional area of the fluid pathway also substantially conforms to the characteristics of the Golden Section.

It is further characteristic of the embodiments that each vane is a vortex generator and that the vanes and chamber combine to form a single main vortex field such that vortices induced by each of the vanes coalesce substantially into a single vortex within the chamber.

It has been found that it is a characteristic of fluid flow that, when it is caused to undergo a fluid flow through a pathway having a curvature substantially conforming to that of the Golden Section that the fluid flow over the surfaces is substantially non-turbulent and as a result has a decreased tendency to cavitate. As a result, fluid flow over the surface is more efficient than has been encountered in previous instances where the pathway does not substantially correspond to that of the Golden Section. As a result of the reduced degree of turbulence which is induced in the fluid in its passageway through such a pathway, the rotors, according to the various embodiments, can be used for conducting fluid with less noise and with a greater efficiency than has previously been possible with conventional rotors of equivalent dimensional characteristics.

In Figure 2, 3 and 4 there is illustrated a blower fan 10 of conventional centrifugal design. The blower fan 10 according to this design comprises a housing 21 which forms a fan chamber 22 of a generally spiral configuration comprising a rear panel 23, a front panel 24 having a circular opening 25 substantially centrally located within the front panel 24, the circular opening 25 having a central axis, the front and rear panels being joined by an outer panel 27 at their outer perimeters 28 to enclose the space between to provide the fan chamber 22, the outer perimeters 28 being in the form of a spiral segment spiralling about the said central axis of the circular opening 25 to provide a radially directed opening as the outlet 29 of the fan. It will be seen that in this design the rotor 11 comprises a circular disc 12 having a central aperture 13 adapted to receive an axle driven by a suitable motor to rotate the rotor. Extending transversely from the disc frame is a plurality of vanes 15 spaced uniformly adjacent the circumference 14 of the disc 12. Each vane 15 has a substantially semi-circular profile so that each vane 15 can be considered as a cylindrical segment. Each vane 15 is arranged with an inner edge 16 disposed towards the central aperture 13 such that, at that inner edge 16, the curvature of the cylindrical segment is substantially tangential to a contacting radius extending from the centre of the disc 12, as depicted by the line A-A shown in Figure 4. Due to the curve of the vanes, at the outer edges 17 of the vanes the curvature is directed obliquely to a radius, typically at angle in the vicinity of 45 degrees. In many designs of such rotors, the edges of the vanes opposed to the disc 12 are linked by a ring 18. This reduces the flexing of the blades when in use, although this is found not to be necessary where the blades and their mounting to the disc are sufficiently stiff.

It is a peculiar characteristic of such blower fan rotors that they blow air outwardly from the central axis region when rotated in either direction, although the efficiency and noise output may be better in one direction of rotation than in the other.

It is another characteristic of such rotors that they need to operate within the confines of a housing in order to guide the airflow in an appropriate manner. This may be contrasted with at least some axial flow rotors such as propellers which can provide a suitable function even when not enclosed within a housing. As a result, the overall performance of a centrifugal pump depends not only upon the design of the rotor, but also of the housing.

In the design of the such fans, it is common for air to enter the fan chamber 22 through the circular opening 25 via a suitable cowl (not shown) covering the circular opening. Often the cowl also supports the fan motor, although in some designs, the motor is mounted on the opposite (rear) side of the housing. The first embodiment which is shown in Figures 5 to 7 comprises a centrifugal blower fan which can be utilized for delivery of high pressure fluid from the outlet and it is anticipated that one particular use would be as a blower which can be used in such applications as improving combustion in furnaces.

The blower fan 30 according to the first embodiment comprises a housing 21 of substantially identical form to the housing of the conventional fan 10 described above and so in the drawings, like numerals are used to depict like parts. The rotor 31 according to the embodiment again is provided with a vane supporting member 32, although this has the form of a bowl or member like a disc with the central portion pushed laterally out from the plane of the disc. The bowl 32 is driven by a central axle 33 connected to a motor.

The embodiment incorporates four vanes 35 supported by the bowl 32. Each vane is a substantially rigid member of uniform thickness and having a general tear-drop configuration with the narrow end adjacent the central axis and extending in a generally radially-outwardly direction therefrom. The bulge in the supporting bowl is configured to correspond to the curve of the vanes. The opposed surfaces of each vane have a three-dimensional, curved configuration which conforms to the characteristics of an equiangular or Golden Section. The vanes are positioned and configured so that, in use, air which is drawn in through the circular opening 25 in a generally axial flow strikes the vanes and is deflected in a direction generally transverse to the axle in a flow which is directed in generally outwardly towards the periphery of the rotor. At the same time, as a result of the curvature of the vanes which conforms with the equiangular or Golden Section, the air is also caused to adopt a vortical flow generally along the path of the vane, as indicated in Figure 6 by the dotted arrows A. Vortical flow is the naturally preferred manner of flow of fluids and is substantially non-turbulent. As a result, efficiency is increased and noise is reduced, compared with conventional rotors.

It is to be understood that adaptations of fans according to the first embodiment may incorporate a number of vanes other than four, and that performance characteristics may be varied as a result. Nevertheless, when a prototype of the rotor according to the embodiment which had four vanes was tested, a significant increase in efficiency was observed in comparison with the conventional rotor as described above while noise generated was reduced significantly.

A second embodiment of the blower fan according to the invention is depicted in Figure 8. This embodiment differs from that of the first embodiment only in that the vanes 35 are mounted in the opposite orientation relative to the spiral of the housing 21. In all other respects it functions identically to the first embodiment. This embodiment shows that the rotor will function in either orientation.

A third embodiment of a rotor according to the invention is depicted in Figure 9. In this embodiment, the fan blades 35 are attached directly to the driving axle 33 and no supporting bowl or panel is provided. Instead the rear panel 23 is configured to substantially conform with the curve of the sides of the vanes 35 so that when assembled, there is only a small gap between the vanes and the end wall.

While in this embodiment the general appearance is quite similar to that of many axial-flow rotors, it should be appreciated that the rotor of the embodiment may be distinguished from such rotors in that the configuration of the vanes causes a very different flow pattern to that of any axial-flow rotor. An axial flow rotor causes the fluid to flow substantially in an axial direction whereas the rotor according to the embodiment deflects fluid flow generally outwardly toward the outer periphery of the rotor, thereby the average flow having a substantial average component in a radial direction or at a direction transverse to the axis of rotation, as indicated by the spiralling arrows A. The average flow will also be given a component in a centrifugal direction.

A fourth embodiment of the rotor 41 according to the invention is depicted in Figure 10. The rotor 41 of this embodiment is somewhat similar in appearance to that of the conventional rotor 11 described above. As may be seen in Figure 10, the rotor 41 comprises a plurality of smaller vanes 45 evenly spaced around the perimeter of the rotor 41. In contrast with the conventional rotor 11 and in common with the previous embodiments, the vanes 45 of the fourth embodiment have a curved surface conforming to the Golden Section. This configuration of the vanes causes the vanes to act as vortex generators and to cause flow across the vanes to be vortical.

The embodiments described above have disclosed rotors which may be used effectively to replace a conventional rotor even within an existing housing of the type described above. When such a replacement is made, some improvement in performance is shown. Nevertheless, the housings of conventional blower fans have not been designed to cooperate with a vortical flow pattern across the rotor. It has been observed in initial testing that the vortical flow occurring in a fan incorporating a rotor according to the embodiments may not be limited to localized vortices generated in relation to the vanes, only. Rather, a more general vortical flow can be established through the fan housing. This vortical flow commences in the inlet region and extends through the rotor into the outlet region. The degree and efficiency to which this vortical flow is established depends to some extent on the configuration of the housing as well as the rotor. The result will be optimized if the principles disclosed by the present applicant in its previous international patent application PCT/AU03/00004 (WO03/056228 A1) are applied to the design of the fan housing. In particular, the housing should be designed so that a significant portion of the inner surfaces of the housing should be designed with a curvature conforming to the Golden Section. In doing so, interference to vortical flow will be minimized, thereby further reducing turbulence and noise and increasing efficiency. In addition it has been found that the cross- sectional area of the fluid-flow path should preferably be designed to decrease or increase at a rate conforming to the Golden Ratio. A fifth embodiment of a centrifugal fan designed according to the above mentioned principles is depicted in Figures 11 to 13. It may be noted that the embodiment comprises a housing 51 with a configuration which is substantially similar to that of a seashell or a snail. Further, it can be seen that the adoption of a rotor support 53 in the form of bowl with a profile corresponding to the curve of the vanes rather than a flat disc is a feature that assists to promote vortical flow within the housing.

In this way it can be seen that by carefully designing both the rotor and the inlet and outlet ducts of the housing to conform to the Golden Section, a fan is provided which promotes vortical flow through the fan housing and thereby operates more efficiently and with lower noise output than an equivalent device according to conventional design practices.

While the adoption of such a housing has been found to promote vortical flow when used with a rotor of centrifugal design, it has also been found that it cooperates with a rotor of axial design to promote vortical motion, especially if the rotor has been designed with surfaces having a curvature conforming with the Golden Section. It is believed that this result occurs because an axial rotor will still try to establish vortical flow and that such flow will be encouraged where the design of the housing promotes vortical flow. This finding has led to a further development in relation to the fifth embodiment, By utilizing a housing described in relation to the fifth embodiment, it has been recognized that a rotor need not be designed to be axial only or centrifugal only, but rather may adopt a configuration that promotes a balance between both axial and centrifugal flow. The output will depend upon the precise configuration of the vanes of the rotor. It will be appreciated that by careful design, the rotor may provide a performance anywhere between purely axial and purely centrifugal. For example, by selecting a fan impeller having a configuration to provide a desired output intermediate between axial and centrifugal, matched with an appropriate housing, the designer can achieve a balance between pressure and flow that more appropriately matches the design criteria, while maintaining efficient performance and low noise.

While the embodiments referred to above have been described with respect to the application to a blower fan where the fluid is a gas such as air, it is to be appreciated that the principles of the invention may be applied to a broad range of fans and also to pumps where the fluid is a liquid. In such applications, the vortical fluid flow is seen to reduce or even eliminate cavitation which also reduces wear on the rotor, as well as increasing efficiency and reducing noise.

Even further, the invention may be applied to applications where the rotor is driven by the flow of fluid over the rotor, as in the case of turbines, still providing the advantages as already described. It is a further characteristic of the invention that the flow of fluid over the surface of the rotor results in significantly less friction and impact forces being imposed upon the surface and the rotor. As a result of this and the reduced turbulence created by the rotor there is less heat and noise generated as a result of the action of the rotor and thus imparted into the fluid. In addition the rotor requires less energy to effect similar flow rates to conventional fans and pumps. This means that the rotor when used in a pump can be driven by a smaller drive motor and/or at a lower speed.

The rotor of the invention has application to use in blower fans, pumps, turbines, and fluid powered motors and can be used to advantage in any proposed application of such, at least because of the enhanced fluid flow, reduced friction, and reduced heat gain when used in a fan or pump and heat loss when used as a turbine.

It is to be understood that the design of any particular fan involves a compromise between flow, efficiency and noise. While even a conventional design may be varied significantly to obtain particular characteristics, testing of fans according to the embodiments has indicated that where a rotor is provided to conform to one, particular characteristic and compared with a conventional rotor providing an equivalent performance according to that characteristic, then the rotor according to the embodiments outperforms the conventional rotor in relation to the other characteristics.

It should be appreciated that the scope of the present invention need not be limited to the particular scope described above.

Throughout the specification, 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.

Claims

The claims defining the invention are as follows:

1. A rotor for use with a fluid flow generator or reactor, said rotor being rotatable about a central axis of the rotor and having a at least one vane arranged, in use, to induce a generally axial fluid-flow into the central axial region of the rotor and an outward flow from the central axial region of the rotor to the outer periphery of the rotor, wherein the at least one vane comprises a vortex generator adapted to accelerate the fluid away from the central axis of the rotor in a vortical motion.

2. The rotor as claimed at claim 1 wherein the outward flow comprises an average flow with a substantial radial component.

3. A rotor as claimed at claim 1 or claim 2 wherein the at least one vane comprises an element which is a vortex generator.

4. A rotor as claimed at claim 1 or claim 2 wherein the at least one vane is configured as a vortex generator.

5. A rotor as claimed at any one of the preceding claims wherein each of the at least one vane comprises a surface which has a configuration of a logarithmic curve substantially conforming to the equiangular or Golden Section.

6. A rotor as claimed at claim 5 wherein the curvature of the surfaces are transverse or perpendicular to the central axis.

7. A rotor as claimed at claim 5 wherein the curvature of the surfaces can be in a direction parallel to the central axis.

8. A rotor as claimed at claim 5 wherein the curvature of the surfaces are both transverse to the central axis and parallel to the direction of the central axis to define a three dimensional surface conforming to the equiangular or Golden Section.

9. A rotor as claimed at any one of claims 5 to 8 wherein the rotor comprises an impeller which is adapted to be driven to rotate about its central axis to induce fluid flow over the surface.

10. A rotor as claimed at any one of claims 5 to 8 wherein the rotor is adapted to be subjected to a fluid flow over said surface to induce a rotation of the rotor about the central axis.

11. A rotor as claimed at any one of the previous claims wherein the at least one vane of the rotor is configured to the induce the average of the vortical motion to have both an axial and a radial component.

12. A rotor according to any one of claims 1 to 11 wherein the rotor comprises a rotor support in the form of bowl with a profile corresponding to the curve of the vanes to thereby promote vortical flow.

13. A centrifugal blower fan, pump or turbine comprising a housing and a rotor as defined in any one of claims 1 to 12.

14. A centrifugal blower, fan, pump or turbine as claimed at any one of the previous claims wherein the housing comprises inlet and outlet ducts configured with active surfaces having a curvature substantially conforming to the equiangular or Golden Section configured to promote fluid flow through the housing to be vortical.

15. A centrifugal blower fan, pump or turbine comprising a housing and a rotor, the housing defining a chamber having a substantially central axis about which said rotor rotates, the rotor being supported within the chamber for rotation, the chamber having an outlet formed at the periphery of the chamber and an opening formed in a wall of the housing which is substantially centrally located relative to the central axis; said rotor having at least one vane which extends in a generally outward direction away from the central axis to direct fluid flow across the rotor in a generally outward flow from the central axial region of the rotor to the outer periphery of the rotor; the surfaces defined by the opposed faces of the vanes being curved wherein the curvature of the surface has the characteristics of a logarithmic curve substantially conforming to an equiangular or Golden Section and are thereby adapted to induce vortical flow when in use.

16. A centrifugal blower fan, pump or turbine as claimed at claim 15 wherein the cross-section of the vane generally increases between the inlet and outlet where the variation in cross-section of the vane varies logarithmically in substantial conformity to an equiangular or Golden Section.

17. A centrifugal blower fan, pump or turbine as claimed at claim 15 or 16 wherein the rotor is configured to induce vortical flow which has an average flow with both an axial and a radial component.

18. A centrifugal blower, fan, pump or turbine as claimed at any one of claims 15 to 17 wherein the housing comprises inlet and outlet ducts configured with active surfaces having a curvature substantially conforming to the equiangular or Golden Section configured to promote vortical fluid flow through the housing.