Abstract:
A fluid flow control device that controls a flow of fluid within the flow control device has a flow path to convey the fluid. A cross-sectional area of the flow path varies along the flow path. At least a portion of the length of the fluid flow control device includes an active surface capable of influencing the fluid flow through the flow path to cause vortical motion of the fluid within the fluid pathway.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation and claims the priority benefit of U.S. patent application Ser. No. 11/323,137, filed Dec. 29, 2005, which claims the priority benefit of Patent Cooperation Treaty application number PCT/AU2004/000862, filed Jun. 29, 2004, which in turn claims the priority benefit of Australian patent application number 2003903386 filed Jul. 2, 2003. The disclosure of these commonly owned applications is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to nozzles, diffusers and venturis. It may be applied in any application in which nozzles, diffusers and venturis are used. 
         [0004]    2. Description of the Related Art 
         [0005]    Nozzles, diffusers and venturis are specific types of ducts used in relation to the flow of fluid. For the purpose of this specification, a nozzle is intended to mean a duct of varying cross-sectional area which is designed so that fluid flow is accelerated by a pressure differentiated between the inlet and the outlet. A diffuser is intended to mean a duct of varying cross-sectional area which is designed so that fluid flow is decelerated by an increase of pressure between the inlet and the outlet. A venturi can be seen as a duct comprising a nozzle section and diffuser section abutted in tandem. 
         [0006]    Nozzles are widely used in the field of fluid flow as a means to provide an accelerated stream of fluid and have many applications. Diffusers are used to decelerate fluid flow and again have many applications. Venturis are used to cause a short region of accelerated flow in a duct. It is a well known law of thermodynamics that the accelerated fluid flow is accompanied by a reduced pressure, and that many applications of venturis are directed to utilising the reduced pressure. 
         [0007]    While nozzles, diffusers and venturis are widely used, it is also well known that their performance is affected considerably by turbulence and frictional losses. These factors significantly limit the uses to which such devices can be applied. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, an exemplary embodiment of the present invention provides a flow controller adapted to control a flow of fluid within the controller, the flow controller having a flow path adapted to convey said fluid, wherein the cross-sectional area of the flow path varies along the flow path and wherein in at least a portion of its length the flow controller comprises an active surface capable of influencing the fluid flow through the flow path. 
         [0009]    According to an exemplary embodiment of the invention, the active surface is adapted to cause rotational motion of fluid within the fluid pathway about the axis of flow of the fluid. 
         [0010]    According to an exemplary embodiment of the invention, the active surface is adapted to cause vortical motion of fluid within the fluid pathway about the axis of flow of the fluid. 
         [0011]    According to an exemplary embodiment of the invention, the configuration of the active surface conforms to at least one logarithmic curve conforming to the Golden Section. 
         [0012]    According to an exemplary embodiment of the invention the curvature of the active surface is uni-dimensional. 
         [0013]    According to an exemplary embodiment of the invention the curvature of the active surface is bi-dimensional. 
         [0014]    According to an exemplary embodiment of the invention, the curvature of the active surface varies in accordance with the Golden Section. 
         [0015]    According to an exemplary embodiment of the invention, the curvature of the active surface conforms to an equiangular spiral. 
         [0016]    According to an exemplary embodiment of the invention the curvature of the active surface is transverse to the central axis of the fluid pathway. 
         [0017]    According to an exemplary embodiment of the invention the curvature of the active surface can be in a direction parallel to the central axis. 
         [0018]    According to an exemplary embodiment of the invention the curvature of the active surface is both transverse to the central axis and is parallel to the direction of the central axis to define a three-dimensional surface conforming substantially or in the greater part to the Golden Section. 
         [0019]    According to an exemplary embodiment of the invention, the fluid pathway has a spiral configuration. According to a preferred embodiment the configuration takes the form of a logarithmic helix or a volute or a whorl. 
         [0020]    According to an exemplary embodiment of the invention, the cross-sectional area of the flow path varies logarithmically substantially or in greater part in conformity to the Golden Section. 
         [0021]    According to an exemplary embodiment of the invention, the cross-sectional area of the flow path varies to cause the incremental volume of the flow path to vary logarithmically. 
         [0022]    According to an exemplary embodiment of the invention, the incremental volume is caused to vary in conformity with the Golden Ratio. 
         [0023]    According to an exemplary embodiment of the invention, the active surface has the configuration conforming to the external configuration of a shell of the phylum Mollusca, class Gastropoda or Cephalopoda. According to exemplary forms of the invention the active surface conforms to the external configuration of shells selected from the genera Volutidea, Argonauta, Nautilus, Conidea or Turbinidea. 
         [0024]    According to an exemplary embodiment of the invention, the active surface has the configuration of the interior of shells of the phylum Mollusca; classes Gastropoda or Cephalopoda. In particular embodiments, the active surface has the configuration of the interior of shells selected from the genera Volutidea, Conidea, Turbinidea, Argonauta, or Nautilus. 
         [0025]    According to an exemplary embodiment of the invention, the configuration of the flow controller promotes substantially radially laminar fluid flow. 
         [0026]    According to an exemplary embodiment of the invention, the flow controller comprises a nozzle. 
         [0027]    According to an exemplary embodiment of the invention, the flow controller comprises a diffuser. 
         [0028]    According to an exemplary embodiment of the invention, the flow controller comprises a venturi. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a chart of the Golden Section or Fibonacci Progression; 
           [0030]      FIG. 2  is an isometric view of a nozzle according to a first embodiment; 
           [0031]      FIG. 3  is an isometric view of a nozzle according to a second embodiment; 
           [0032]      FIG. 4  is an isometric view of a nozzle according to a third embodiment; 
           [0033]      FIG. 5  is an isometric view of a diffuser according to a fourth embodiment; 
           [0034]      FIG. 6  is a sectional elevation of a conventional venturi tube; 
           [0035]      FIG. 7  is an isometric view of a venturi according to a fifth embodiment; 
           [0036]      FIG. 8  is an isometric view of a venturi according to a sixth embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    An embodiment of the invention is directed to a flow controller, the structure of which is configured to cause the rate of a fluid flow to be altered during passage through the controller. Each of the embodiments is directed to a flow controller adapted to alter the rate of flow of a fluid. 
         [0038]    It has been found that 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 mathematical progression known as the Golden Ratio or a Fibonacci-like Progression. 
         [0039]    Each of the embodiments serves, in the greater part, to enable fluids to move in their naturally preferred way, thereby reducing inefficiencies created through turbulence and friction which are normally found in apparatus commonly used for propagating fluid flow. Previously developed technologies have generally been less compliant with natural fluid flow tendencies. 
         [0040]    The greater percentage of the surfaces of the flow controller of each of the embodiments described herein are generally designed in the greater part, in accordance with the Golden Section or Ratio or are designed to ensure the volume of fluid flowing through the flow controller expands or contracts in the greater part in accordance with the Golden Section and therefore it is a characteristic of each of the embodiments that the flow controller provides a fluid pathway which is of a spiralling configuration and which conforms at least in greater part to the characteristics of the Golden Section or Ratio. 
         [0041]    The characteristics of the Golden Section are illustrated in  FIG. 1  which illustrates the unfolding of the spiral curve according to the Golden Section or Ratio. 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 : 0 . 618  approximately and which is consistent throughout the curve. 
         [0042]    It is a characteristic of each of the embodiments that the curvature of the surfaces which form the flow controller takes a two dimensional or three dimensional shape equivalent to the lines of vorticity or streak lines found in a naturally occurring vortex. In general, the curvature of the surfaces substantially or in the greater part conform to the characteristics of the Golden Section or Ratio and that any variation in cross-sectional area of the flow controller also substantially or in greater part conforms to the characteristics of the Golden Section or Ratio. In at least some of the embodiments, the curvature of the active surface conforms to an equiangular spiral. Furthermore it has been found that the characteristics of the Golden Section or Ratio are found in nature in the form of the external and internal configurations of shells of the phylum Mollusca, classes Gastropoda and Cephalopoda and it is a common characteristic of at least some of the embodiments that the fluid pathway defined by the flow controller corresponds generally to the external or internal configuration of shells of one or more of the genera of the phylum Mollusca, classes Gastropoda and Cephalopoda. 
         [0043]    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 or in greater part conforming to that of the Golden Section or Ratio 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 or in greater part 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 flow controllers according to the various embodiments can be used for conducting fluid with a greater efficiency than has previously been possible with conventional flow controllers of equivalent dimensional characteristics. 
         [0044]    To assist the reader&#39;s understanding of the embodiments, the outer surfaces of the embodiments in the drawings are depicted in a way whereby they would correspond with the inner surfaces, such as would be the case if the walls of the embodiments are of constant thickness. In this way some concept of the helical/spiral configurations of the inner surfaces is conveyed. In practical fluid flow control devices, the configuration of the outer surface is not of significance to the embodiments and thus the outer surface could be configured as a simple surface such as a cone., leaving the inner surface complex as suggested in these drawings. 
         [0045]    The first embodiment takes the form of a nozzle as shown in  FIG. 2 . The nozzle  11  has a nozzle body  21 , an outlet  22  and an inlet  23  which is adapted to be joined to a duct (not shown) such as a pipe, hose or similar providing a source of fluid under pressure. The nozzle body  21  has an internal surface  25  which reduces in cross-sectional area to the outlet  22 . In addition, the internal surface of the nozzle may be seen to twist in a combination helical manner and spiralling manner between the input and the output. As indicated above, this twist is in a configuration which provides an active surface which conforms at least in greater part to the characteristics of the Golden Section or Ratio. It will be seen that as a result of the twist, fluid flowing in the nozzle is caused to be given a rotational motion about the longitudinal axis of the nozzle to thereby induce vortical motion in the fluid. 
         [0046]    As a result of the vortical motion, the turbulence and friction in the nozzle are reduced considerably from that observed in a conventional nozzle having a simple conical internal surface. 
         [0047]    A second embodiment takes the form of a nozzle as shown in  FIG. 3 . The second embodiment is of substantially similar construction to that of the first embodiment, and therefore in the drawings like parts are denoted with like numerals. The second embodiment differs from the first only in the particular design of the nozzle in that it is relatively longer and has greater twist. By varying the parameters of the nozzle, the formation of the vortical flow emitted from the nozzle outlet can be controlled. In certain applications, it will be desirable for the outlet to comprise a narrow vortical stream while in others, a diverging stream will be required to promote mixing of the output with the surrounding fluid. 
         [0048]    A third embodiment takes the form of a nozzle as shown in  FIG. 4 . In this embodiment, the twist in the flow surfaces causes the direction of flow to be diverted transversely to that of the incoming flow stream. This redirection is achieved without significant loss because the internal surface of the nozzle is still configured to conform at least in greater part to the characteristics of the Golden Section or Ratio. As a result, turbulence is substantially avoided. 
         [0049]    It will be appreciated that a whole class of embodiments are possible whereby the output flow is directed obliquely relative to the direction of the input flow stream. 
         [0050]    A fourth embodiment takes the form of a diffuser as shown in  FIG. 5 . It may be appreciated that a diffuser may comprise a flow controller substantially identical to a nozzle but with direction of flow reversed. In this regard, the diffuser of  FIG. 5  corresponds with the nozzle of  FIG. 2  but having an internal surface  25  which increases in cross-sectional area to the outlet  22 .. Therefore, in the drawings like numerals are again used to depict like features. As with the nozzle, while the diffuser of  FIG. 4  will induce vortical motion in the fluid flow, the precise characteristics of the output flow can be controlled by varying the design properties of the diffuser while maintaining the inner surface to conform at least in greater part to the characteristics of the Golden Section or Ratio. 
         [0051]    It has been previously been noted that the cross-sectional area of the previous embodiments varies between the inlets to the outlets; for the nozzles, the area decreasing and for the diffusers, the area increasing. In a further development of the previous embodiments, it has been found advantageous, at least in certain circumstances to vary the incremental volume of the controller along the fluid pathway in a manner that conforms to the characteristics of the Golden Section or Ratio. To take advantage of this aspect, further embodiments of the fluid flow control devices as previously described are configured to conform with this constraint. As a result, the volume of fluid flowing through the flow controller expands or contracts in the greater part in accordance with the Golden Ratio. 
         [0052]    A fifth embodiment takes the form of a modified venturi tube as shown in  FIG. 7 . The modified venturi tube is best appreciated by comparison with a conventional venturi tube which is depicted In  FIG. 6 . In the conventional venturi tube of  FIG. 6 , a venturi  51  comprises an inlet  52 , an outlet  53  and a constricted region  54 . The constricted region  54  comprises an entry  55 , an exit  56  and a region of maximum constriction  57 . In the drawings, the flow is represented by flow lines  58 . 
         [0053]    When fluid is caused to flow into the inlet  52  of venturi  21 , it is affected by the entry  55  wherein the diameter of the fluid pathway is progressively reduced until the region of maximum constriction  57  is reached. This constriction within the fluid pathway causes the speed at which the fluid is travelling to be increased. In accordance with well known laws of thermodynamics, this increase in fluid speed is accompanied by a reduction in pressure of the fluid. Subsequent to the region of maximum constriction  57 , the fluid flow is affected by the exit  56  wherein the diameter of the fluid pathway is progressively increased to the outlet  53 . In the exit  56 , the fluid is progressively slowed. 
         [0054]    It is known that the energy losses at a venturi are very significant. As mentioned above, these losses are caused both by friction and turbulence. In particular, it is well known that while the performance of a venturi can be increased by increasing the ratio of the inlet diameter relative to the diameter of maximum constriction  57 , it is also known that in practice that any gains achieved by so reducing the region of maximum constriction are rapidly cancelled by the increased losses which result. 
         [0055]    As can be seen in  FIG. 7 , the modified venturi  61  comprises an inlet  62 , an outlet  63 , a region of maximum constriction  64 , an entry  65  and an exit  66 . It will be readily perceived that these portions conform generally to corresponding portions of the conventional venturi tube of  FIG. 6 . In contrast however, the entry  64  and exit  65  are specifically designed to induce the fluid to move in accordance with the laws of Nature. As mentioned previously, the flow controller is designed with a pathway having a curvature substantially or in greater part conforming to that of the Golden Section or Ratio. The fluid is thereby induced into vortical flow the greater part of which conforms to the Golden Section or Ratio. The energy losses caused as a result of this vortical flow are considerably lower than those which result from a conventional venturi. 
         [0056]    As a result of the considerably reduced energy losses caused by the modified venturi of the fifth embodiment, the apparatus may be used more effectively than previously has been possible. Firstly, it is possible to increase the ratio of the area of inlet relative to the area of maximum constriction. This increases the relative pressure difference that may be generated between the inlet and the region of maximum constriction. This broadens the scope of use of the device. 
         [0057]    A sixth embodiment takes the form of a modified venturi tube as shown in  FIG. 8 . The sixth embodiment, although somewhat different in appearance, operates in substantially the same manner as that of fifth embodiment and so, in the drawings, like parts are denoted with like numerals. The sixth embodiment again comprises a duct, the area of cross-section of which reduces from an inlet to a portion of maximum constriction, and then increase to the outlet. The difference between the sixth embodiment and the fifth is that in the fifth embodiment the flow induces a vortex which has an axis of rotation which is co-linearly aligned with the central axis of the inlet, whereas in the sixth embodiment, the axis of rotation of the vortex is disposed substantially transversely to the central the axis of the inlet. 
         [0058]    It has been noted previously that in the embodiments of the modified venturi tube, the cross-sectional area of the duct varies along the flow path, decreasing in the entry and increasing in the exit. As in the examples of the nozzles and diffusers, it has been found advantageous, at least in certain circumstances to vary the incremental volume of the controller along the fluid pathway in a manner that conforms to the characteristics of the Golden Section or Ratio. To take advantage of this aspect, further embodiments of the modified venturi tubes as previously described are configured to conform with this constraint. As a result, the volume of fluid flowing through the entry and exit of the venturi contracts or expands in the greater part in accordance with the Golden Ratio. 
         [0059]    It has been found that, in at least certain configurations of the embodiments, the arrangements promote substantially radial laminar flow and it is believed that this assists the efficiency of the fluid flow within those arrangements 
         [0060]    It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiments described above. 
         [0061]    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.