|WO/2005/106205||BLADELESS FLUID MACHINE|
|JP2008128126||TURBINE UNIT FOR THERMAL POWER GENERATION AND THERMAL POWER GENERATION SYSTEM|
HOLT, Drew (322 First Avenue North, Suite 403Minneapolis, Minnesota, 55419, US)
HOLT, Drew (322 First Avenue North, Suite 403Minneapolis, Minnesota, 55419, US)
1. An apparatus comprising:
a plurality of stacked disks, each disk comprising an opening in the center of the disk, thereby forming a central flow chamber;
a first disk coupled to a bottom of the plurality of stacked disks, the first disk having no opening in the center of the first disk;
a plurality of disk spacers positioned between one or more of the plurality of stacked disks, thereby creating flow channels between the disks, the flow channels extending from an outside perimeter of the stacked disks to the central flow chamber;
a tapered armature coupled to the first disk and positioned within the central flow chamber; and
a fluid collection unit in communication with the outside perimeter of the stacked disks.
2. The apparatus of claim 1 , wherein the tapered armature is tapered away from the first disk and towards an opening of the central flow chamber at a top of the stacked disks. 3. The apparatus of claim 1, comprising means for coupling the plurality of stacked disks to an energy conversion unit.
4. The apparatus of claim 3, comprising the energy conversion unit. 5. The apparatus of claim 3, wherein the means for coupling comprises:
a first shaft coupled to the first disk;
a first metal plate coupled to an end of the first shaft opposite the first disk; and
a second metal plate coupled to a second metal shaft, the second metal plate adjustably positioned in proximity to the first metal plate; wherein the second metal shaft is configured for coupling to an energy conversion unit.
6. The apparatus of claim 5, wherein one or more of the first metal plate and the second metal plate comprise one or more of a conductor plate and a magnetized plate. 7. The apparatus of claim 1, wherein the apparatus is configured such that a fluid enters the fluid collection unit and impinges upon the stacked disks, thereby causing the plurality of stacked disks to rotate about its axis;
the fluid penetrates into the flow channels between the disks and comes into contact with the plurality of disk spacers, and is directed into the central flow chamber by the plurality of disk spacers;
and the fluid enters the central flow chamber and is directed out of the central flow chamber by the tapered armature.
8. The apparatus of claim 1, wherein the apparatus comprises one or more of a wind turbine, a geothermal turbine, a steam turbine, a hydrodynamic turbine, and a pump. 9. The apparatus of claim 1, wherein the fluid collection unit comprises a funnel-shaped opening, and a wall of the funnel-shaped opening comprises a movable panel.
10. The apparatus of claim 1, wherein the disks comprise a composite material.
11. The apparatus of claim 1, wherein the disk spacers are coupled to an outer circumferential edge of a first disk and coupled to an outer circumferential edge of a second disk.
12. The apparatus of claim 1, wherein a surface of a disk is tapered from a position proximate to the central flow chamber to a position near the perimeter of the disk.
13. The apparatus of claim 1, wherein a disk comprises first and second outer layers of a composite material, and a rigid structure positioned in between the first and second outer layers.
14. The apparatus of claim 1, comprising a pair of opposite pole magnets positioned outside of the plurality of stacked disks and proximate to the first disk.
15. The apparatus of claim 1, comprising a valve connected to the fluid connection unit for controlling an amount of fluid entering the plurality of stacked disks.
 The present disclosure relates to the field of turbines, and in an embodiment, but not by way of limitation, a composite boundary layer turbine.
 This application claims priority to United States Provisional
Patent Application Serial No. 61/257,988, filed November 4, 2009, which is incorporated herein by reference in its entirety.
 Boundary layer turbines date back to 1913 with the initial patent filed by Nikola Tesla. However, no successful large turbine has been built and sold for almost one hundred years due in part to material constraints, that material being metal. The art is in need of an economical and commercially viable boundary layer turbine.
Brief Description of the Drawings
 FIG. 1 illustrates a partial cross section of an example embodiment of a stack of turbine disks and disk spacers.
 FIG. 2 illustrates example embodiments of several different profiles for turbine disks and fluid flow channels created by those disks.
 FIG. 3 illustrates a top planar cross section of an example embodiment of a turbine and a fluid collection unit coupled to the turbine.
 FIG. 4 illustrates a cross section of an example embodiment of a turbine including a stack of turbine disks and disk spacers positioned on a disk and including a central flow chamber and tapered armature.
 FIG. 5 illustrates another cross section of the turbine of FIG. 4, and further illustrates the turbine coupled to an energy conversion unit.
 FIGS. 6A and 6B illustrate a perspective and top planar view respectively of a working fluid collection unit coupled to a turbine.  FIG. 7 illustrates a top perspective view of half of a disk including adhesion points and disk spacers.
 FIG. 8 illustrates a top planar view of an example embodiment of a turbine disk with a disk spacer positioned thereon.
 FIG. 9 is a perspective view of a stack of turbine disks.
 In the following description, reference is made to the
accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These
embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and other changes may be made without departing from the scope of the present invention. The following description of example embodiments is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
 Until now, large disk turbines and compressors have not been achievable because in part of the material properties of the metals used in the construction of the turbines. With the advent of modern aircraft technologies, composites have moved to the forefront of the market by virtue of providing high strength and low weight properties, sometimes down to six percent that of equivalent steel structures. Additionally, with modern composites and resins, large disk assemblies can be made with low inertial requirements so as to provide viable wind turbine solutions, for instance. Further applications push into light geo-thermal, steam and hydrodynamic applications as well.
 With modern technologies, composites have moved to the forefront of the market by virtue of providing high strength and low weight properties. With modern composites, resins, and advanced curing systems, large disk assemblies can be made with low inertial requirements so as to provide a light weight and sturdy turbine.
 One or more embodiments of the present disclosure relate to a composite wind turbine including a stacked disk-type boundary layer turbine design. An embodiment incorporates a stacked series of disks on a vertical axis, with a shafted or shaft-less armature inside of a housing enclosing a power section. A fluid (air) flow feeds through a large open collection diffuser area (working fluid collection unit) that is directed towards the wind direction. In an embodiment, the collection diffuser is funnel shaped, and thereby constricts the wind volume axially toward the power section and into a variable area inlet diffuser. The fluid flow is directed in between the stacked series of disks and into a central flow channel between the disks by the diffuser. The flow channels between the disks are created by disk spacers (brackets) between the disks. The disk spacers are an improvement on prior geometric shapes, thereby increasing the efficiency of energy extraction between the fluid flow and the mechanical characteristics, geometrical shape, and surface area of the disks themselves. The majority of the power extracted in the power section of the turbine is from the fluid moving over the surface of the disks. The fluid drags on the disks by means of viscosity and adhesion in the boundary layer of the fluid, and as the fluid slows it transfers energy to the disks. The fluid flow originates from the outside edge of the disks, moves toward the center flow chamber, makes contact with a swirl cone or tapered armature, and spirals and is directed out the turbine.
 FIG. 1 illustrates a stack of disks 100 and disk spacers 110 that can be used in one or more embodiments of the present disclosure. The outer peripheries of the disks 100 of FIG. 1 are tapered. The disk 100 includes a portion 107 that coupled two halves of a disk, and a free air space portion 108. FIG. 2 illustrates other profiles that can be used for the disks 100, including an oval shape 205, a concave taper 210, a half oval 215, a rectangle 220, an extended taper 225, a half point 230, a full point 235, a blunted half point 240, and rounded tips 245 and 250. Each of the profiles of FIG. 2, and different combinations of these profiles, imparts different fluid dynamics in different embodiments. For example, in an embodiment that tapers towards a center of the disk as in 210, a working fluid that impinges on the disk will increase in velocity due to the Venturi effect. Similarly, if a pair of disks 210 and 215 form a fluid channel 216A and 216B, the fluid entering the disk stack at 216A will increase in velocity as it approaches the midpoint of the disks, and then decrease in velocity as it enters 216B. These different profiles and profile combinations can cause increased disk rotation speed and increased power output as will be explained herein.  FIG. 4 illustrates an embodiment of stacked disks 100 and disk spacers 110 positioned on another disk 115. An opening in the center of the disks 110 forms a central flow chamber 125 of the turbine. The disk 115 has either no opening in its center, or only a smaller opening that still permits a tapered armature 120 to be coupled to the disk 115. A working fluid can enter the turbine at the perimeter of the disks 100, and the fluid travels through the flow channels formed by the spaces between the disks and between the arms of the disk spacers 110. As noted, the working fluid impinges on the surfaces of the disks 100, thereby causing the disks to rotate. The working fluid enters the central flow chamber 125, and contacts the tapered armature 120. The tapered armature 120 directs the working fluid away from the armature base and disk 115, and out of the turbine 105. This redirection out of the turbine 105 creates a continuous medium for the incoming working fluid and prevents the buildup of any back pressure.
 FIG. 3 illustrates a top planar view of an embodiment of the turbine 105 and the working fluid collection unit 125. A working fluid enters the unit 125, increases in velocity as it approaches the neck 123 of the unit 125, and enters the power section 122, which is enclosed by housing 130 of the turbine 105. The working fluid will impinge of the disks 100, thereby causing the disks to rotate. The working fluid will further impinge on the disk spacers 110, which direct the working fluid into the central fluid chamber 125. As explained above, the tapered armature 120 directs the working fluid out of the turbine 105. A valve 124 can be adjusted to control the amount of wind or other fluid that enters the power section 122.
 FIG. 5 illustrates an embodiment wherein the turbine 105 is coupled to an energy conversion unit 500. FIG. 5 illustrates the stack disks 100, the spacers 110, the tapered armature 120, and the central fluid chamber 125, all of which are positioned on the disk 115. Attached to the disk 115 is a shaft 505, which is coupled to a metal plate 510. A second plate 515 is coupled to a second shaft 520, and the second shaft 520 is coupled to a generator 525. As the disks 100 and 115 rotate, the shaft 505 and 510 will also rotate. The metal plates 510, 515 can be energized conductor plates or electro-magnetized plates. The electromotive force between the plates 510, 515 will cause the plate 515 to rotate in unison with the plate 510. The rotation of plate 515 causes shaft 510 to rotate, which rotation is converted into current by the generator 525. In this manner, energy is transferred by means of a no contact frictionless inducted
electromotive force torque transfer that occurs across the air-gap between the two conductor plates 510, 515 (or magnet arrays). Besides the generation of current, the rotation of shaft 520 could be used to perform other tasks. For example, besides use as a wind turbine, the turbine 105 can be used as a geothermal turbine, a steam turbine, a hydrodynamic turbine, and a pump. FIG. 5 further illustrates magnet pairs 530. The magnets of the pair 530 are of opposite polarity, and are used to support the turbine 105. In another embodiment, a bearing or bearings can be used to support the turbine 105.
 FIGS. 6A and 6B illustrate an embodiment of a fluid collection unit 125 coupled to the turbine 105. The working fluid will enter the funnel opening of the fluid collection unit 125, increase in velocity due to the Venturi effect, and enter the power section 122 of the turbine 105. In case of storms or other high wind conditions in which excessively high winds could damage the fluid collection unit and/or the turbine 105, panels 127 are designed such that they can be opened to allow the wind or other working fluid to pass through the unit 125 and not substantially enter the power section 122 of the turbine 105. An exhaust pipe 128 is attached to the top of the turbine 128.
 FIGS. 7 and 8 illustrate an example embodiment of a disk and disk spacer. In particular, FIG. 7 illustrates a half portion of a disk 100 that includes the disk spacer 110 and adhesion points 107 for attachment to the other half of the disk. Reference number 108 indicates free air space. Similarly, FIG. 8 illustrates an embodiment of a disk 100 and a spacer 110. FIG. 8 further illustrates an example rib design 109. In an embodiment, the disk includes first and second outer layers of a composite material, and a rigid structure 109 positioned in between the first and second outer layers. FIG. 9 illustrates a perspective view of a disk stack including disks 100, tapered armature 120, and central fluid channel 125.
 The flow area between the disks receives fluid as the working surfaces of the turbine interact with the working fluid. In an embodiment, a flat-disk with beveled edge is implemented with a surface for bonding two disk components together at the outer edge as shown in FIG. 1. In another embodiment, as seen in FIG. 2, the disk surface is angled up to the flow chambers with bonding occurring at the outer edge as well. In this embodiment, the disks are shaped such that they can be bonded together into a single unit. Other options for disk assembly include constructing the disks from fiberglass and filling the disks with internal ribs, foam, plastic or any other type of lightweight potentially recycled filler to provide structural integrity to the final unit.
 An embodiment is a shaft-less design. While most turbines are mounted on a shaft to create a rotor assembly, this turbine design has eliminated material in the central flow chamber and removed the need for a shaft. Instead, the first (top) and last (bottom) disks are used as mounting surfaces for bearings, energy transfer shafts, and so forth. In a current embodiment, two composite disks are shaped to form both disk and bracket/spacer.
 The space between the disks or gap width in flat disk assemblies is dependent on the size of the boundary layer flow over the disks. This will vary with the diameter of the disks as a function of wind speed. For example, it has been found that a gap of approximately half an inch with a one meter diameter turbine is too large, while for a six meter diameter turbine, this might prove to be too small of a gap.
 For larger models where the simple two-disk design is not sufficient, ribs can be placed between the disks for structural support and stiffening. The ribs can be structurally made from metal or composite materials or any variant of composite.
 In an embodiment, apposing polarity magnets levitate ( Mag-
Lev) the disk sections with ceramic coated thrust bearings used to stabilize the turbine and to keep it running true. In a further embodiment, roller bearings are used in place of the the Mag-Lev bearings.
 One or more embodiments are particularly useful for an induced electromotive force used for torque transfer. A physical separation of two conductor elements and/or a combination of magnets and induced conductive plates can be used. The torque is transferred from the turbine across the air gap to the load. Varying the distance between the plates changes the resistance which controls the input speed from the wind turbine to the load. An advantage is that there is no loss of torque due to heat build up from friction.  The large diffuser or fluid collection unit used for wind or other fluid collection is used to funnel the fluid ( wind ), thereby constricting it as the fluid flow gets closer to the diffuser to make its entrance into the power section. The diffuser can be very large, depending on the turbine size. This large surface area lends itself to extreme weight problems if made using standard construction methods of flat rigid panels— no matter what the material. An current embodiment of the diffuser is a constructed frame made of a open lattice. In an embodiment, a disk is constructed of a two dimensional composite beam structure. This structure uses composite beams that are mechanically or chemically bonded together to create a frame. Fabric made from Dacron, Milar, or various other materials is then used to cover the frame and shrunk until it is taught using heat and or radiation energy. The inherent design of the frame and the pre-loading of the shrunk fabric onto the frame lends itself to further strengthening of the frame.
 To aid in longevity and lessen structural impact of high velocity winds related to storm systems, the current embodiment incorporates air pressure dump panels in the diffuser collection frame. The succession of resistive loaded or "gill's" open at different points along the length of the collection diffuser. Spring, air, hydraulic, pressure or other means of resistive pressure hold the panel closed during lower wind conditions, thereby forcing that panel area to direct fluid to the power section. As higher winds increase air pressure inside the collection diffuser, the successive panels open up to dump the air pressure to eliminate stress on the diffuser.
 The ribs can be made in various fashions. First, they can be formed from composite fabric as T-shaped, I-shaped, or any other solid structure to support the distance between the two skin layers. They can also be used piece-wise, where solid "tabs" are placed in strategic locations to assure strength of the unit and geometric continuity. The above spacing structures or ribs can be connected with tape or tow. They also may be comprised of only tape or tow or any combination of composite materials. The limiting factor in the ribs is that the entire structure is not capable of being made from one single strand of tow, tape, or other material. FIG. 8 illustrates an example embodiment of a rib structure with fabric, tow, or tape composite material impregnated with resin. As a two-dimensional disk design, the rib structure concept is entirely novel. These can be created through wrapping tools bordering the top and bottom or compressed on the sides or a combination of them all. Hard tooling is recommended for creating the ribs to allow for tolerances to be held tight.
 Large disks (more than 12 inches in diameter) can be
compounded to create a turbine. A group of two or more disks including at least one disk spacer or bracket, and a disk with no flow channel comprise a unit which can be stacked as high as the designer chooses. As long as the flow chambers of the disks are connected to provide a single passage way for the fluid flow, a single turbine unit is created. In an embodiment, the disks can be stacked without material in between, in contrast to the embodiments with a spacer or bracket that creates a gap.
 Boundary layer turbines have not successfully been manufactured from composite materials with a diameter greater than 12 inches where the disks are built with a method other than layering fabric to build a solid disk. In one or more embodiments disclosed herein, the disks are hollow with a composite skin laid over composite ribs of any given configuration. FIG. 1 shows a disk that is bonded on the outer edge. In this fashion it is possible to build light weight disks of large diameter with the structural strength to support themselves and maintain stiffness as the diameter of the disk increases over various models. This is an advantage over the standard solid layered fabric to reduce weight and maintain stiffness strength. Using composite materials to build a boundary layer turbine where the limitations of weight and diameter are overcome cannot currently be accomplished through traditional methods. This turbine can also be made from polymers, plastics, composites, glass or aramid fibers in a slurry or impregnated with resin.
 The skin used in the construction of a disk can be fabricated separately as a sheet to which the ribs, also fabricated separately, can be epoxied and/or mechanically attached. The top skin is also attached in like manner. These can be assembled in a secondary cure process where some of the parts are manufactured and cured before assembly. Then the unit is assembled and cured a second time. Further, they can be created and cured all at once in a co-cure process. It is recommended that the turbine assembly be cured in sections which are then assembled. These sections can comprise a rib-skin-spacer-skin system. Such systems are then stacked and epoxied and/or mechanically fastened to each other. Another system would be to build the disks and the spacers/brackets separately. They would then be assembled piece- wise into a turbine. Any combination of the above is possible.
 Another possible method is through injection molding. In such a case, fiber can be mixed into a resin slurry and injected into an open or closed mold to produce the desired geometry. Further, plastic-based composites or other materials can be used to manufacture one or more embodiments.
 The larger the diameter of the unit, the more it benefits from variations in cross-sectional shape of the disk itself. This can vary in range from beveled or rounded edges over a constant cross-section to linear or non-linear thickness variations as a function of radial location on the disk. In an embodiment, it can be preferred to implement either flat disks or those that linearly vary with radial location. It would be within the level of skill of a designer to use the geometries of FIG. 2 or similar geometries to the greatest fluid mechanical advantage. For this purpose, a beveled or rounded outer edge is beneficial with any disk geometry. Such an edge forces the fluid to compress or increase its velocity, ever so slightly, into the gap between the disks; the larger the disk, the more critical the edge geometry of the disk.
 The housing is unique in that the airflow exits axially. Included in this housing is a variable area diffuser or collection unit as well as an exit nozzle to better control the airflow. In areas where the wind comes
predominately from a single direction, the fluid collection unit can be fixed in a single position or direction. In another embodiment, the fluid collection unit can be mounted on a swivel bearing to follow the wind or other fluid when it comes from various directions. In an embodiment, the air or other fluid will flow out axially in a preferably vertically down (or vertically up) direction, although the exit direction (up or down) is not relevant to the performance of the turbine. With an axial flow exit, the housing is unique over all the pervious art of similar design with diffusers or variable inlets.
 In an embodiment, two or more fluid collection units or other inlets can circumscribe the turbine while the exit is axial. Thus, a quasi-omnidirectional inlet can be achieved through the addition of various variable area inlets and diffusers. As opposed to other omni-directional designs or even pseudo-omni-directional, this invention uses the variable area inlet in a fashion which allows it to close completely when not ingesting wind or fluid flow. This provides a concentration of fluid flow through the housing thus maximizing the energy transfer from the fluid to the turbine. The actual fluid flow directions which can be excepted in this configuration. Note that this type of housing can be well hidden underneath a cupola or other architectural structure for aesthetic purposes. The option of covering the diffuser with a grill, screen or other material to straighten the flow of the fluid and prevent wildlife and unwanted objects from entering the flow path are also demonstrable.
 Thus, an example composite boundary layer wind turbine has been described. Although specific example embodiments have been described, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disklosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.
 Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disklosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.  The Abstract is provided to comply with 37 C.F.R. § 1.72(b) and will allow the reader to quickly ascertain the nature and gist of the technical disklosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
 In the foregoing description of the embodiments, various features are grouped together in a single embodiment for the purpose of streamlining the disklosure. This method of disklosure is not to be interpreted as reflecting that the claimed embodiments have more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disklosed embodiment. Thus the following claims are hereby incorporated into the Description of the Embodiments, with each claim standing on its own as a separate example embodiment.