BLADE TIP TO SHROUD CLEARANCE FOR SHROUDED FLUID TURBINES
Shrouded fluid turbines having features for setting, adjusting or controlling a blade tip-shroud clearance are described. Also described are methods for setting, adjusting or controlling a blade tip-shroud clearance in a shrouded fluid turbine.
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This application claims priority to and benefit of U.S. Provisional Patent Application No. 61/539,312, filed Sep. 26, 2011, the contents of which are incorporated herein by reference in their entirety.
BACKGROUNDA fluid-driven turbine (e.g., a rotor or impeller) encircled in part or completely by one or more shrouds, ducts, or shells may be described as a shrouded fluid turbine. Examples of shrouded fluid turbines include shrouded wind turbines with wind-driven rotors and shrouded hydro turbines with water-driven rotors. Shrouded fluid turbines that are used to generate power from fluids flowing past the turbine may be described as energy extraction shrouded fluid turbines. In shrouded fluid turbines, the shroud channels the fluid past the rotor, which may increase the efficiency of the turbine. A gap between tips of blades of the rotor and an inner surface of the shroud may be described as a shroud-tip clearance or a shroud-tip gap.
SUMMARYExample embodiments described herein include, but are not limited to, shrouded fluid turbines with features for controlling, setting or adjusting a shroud-tip gap. Example embodiments described herein also include methods for controlling, setting or adjusting the shroud-tip gap in a shrouded fluid turbine.
In an example embodiment, a shrouded fluid turbine includes a central hub rotatable about a central axis of the shrouded fluid turbine, a blade, a first shroud and an adjustment mechanism. The blade includes a proximal portion with a blade root coupled to the central hub, a distal portion including a blade tip and a mid-portion disposed between the proximal portion and the distal portion. The first shroud has an inner surface in proximity to the blade tip. The adjustment mechanism is configured to adjust a separation between the blade tip and the shroud inner surface by lengthening or shortening a distance between the blade tip and the central hub.
The first shroud may have mixing lobes, which may include high energy mixing lobes and low energy mixing lobes. The shrouded fluid turbine may also include an ejector shroud located downstream from the first shroud. An outlet of the first shroud may extend into an inlet of the ejector shroud.
The adjustment mechanism may radially retract or extend at least a portion of the blade with respect to the central hub. At least a portion of the blade may be extended or retracted telescopically. The adjustment mechanism may displace at least the distal portion and the mid-portion of the blade in a radial direction with respect to the central hub.
The adjustment mechanism may include a coupling between at least the distal portion of the blade and the proximal portion of the blade that permits at least the distal portion of the blade to be rotationally displaced about a non-radial axis relative to the proximal portion of the blade. The coupling may be a hinge coupling the distal portion of the blade and the proximal portion of the blade.
In another example embodiment, a shrouded fluid turbine includes a central hub rotatable about a central axis of the shrouded fluid turbine, a blade, a first shroud and an inflatable bladder. The blade includes a proximal portion with a blade root coupled to the central hub, a distal portion including a blade tip and a mid-portion disposed between the proximal portion and the distal portion. The first shroud has an inner surface in proximity to the blade tip. The inflatable bladder is associated with the inner surface and configured to change a spacing between the blade tip and the inner surface by changing a distance between at least a portion of the inner surface and the central axis upon inflation or upon deflation of at least a portion of the inflatable bladder.
The inflatable bladder may be coupleable to the first shroud. The inflatable bladder may be integral to the first shroud. The inflatable blade may include a plurality of inflatable chambers.
In another example embodiment, a shrouded fluid turbine includes a central hub rotatable about a central axis of the shrouded fluid turbine, a blade, a first shroud and a hinged pitch mechanism. The blade includes a proximal portion with a blade root coupled to the central hub, a distal portion including a blade tip and a mid-portion disposed between the proximal portion and the distal portion. The first shroud has inner surface portions in proximity to the blade tip. The hinged pitch mechanism is configured to lengthen or shorten a distance between at least some of the inner surface portions of the first shroud and the central axis.
The shrouded fluid turbine may further include a control mechanism to control the positions of at least some of the inner surface portions relative to the central axis. The control mechanism may individually control the position of each inner surface portion for a plurality of the inner surface portions.
In one example embodiment, a shrouded fluid turbine includes a central hub rotatable about the central axis, a blade, a first shroud and a clearance control mechanism. The blade includes a proximal portion with a blade root coupled to the central hub, a distal portion including a blade tip and a mid-portion disposed between the proximal portion and the distal portion. The first shroud has inner surface portions in proximity to the blade tip. The clearance control mechanism repels the blade tip from some of the shroud inner surface portions or repels some of the inner surface portions from the blade tip.
The blade tip or some of the shroud inner surface portions may be repelled magnetically. The clearance control mechanism may include a ferromagnetic material disposed in at least one of the proximal portion of the blade and the shroud inner surface portion. The clearance control mechanism may include an electromagnet.
In another example embodiment, an energy extraction shrouded fluid turbine includes a rotor, a first shroud, and an adjustment mechanism. In some embodiments, the energy extraction shrouded fluid turbine includes an ejector shroud downstream from the first shroud. The rotor includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine. The rotor also includes a blade with a proximal portion including a blade root coupled to the central hub, a distal portion including a blade tip, and a mid-portion disposed between the proximal portion and the distal portion. The first shroud includes an inner surface in proximity to the blade tip and mixing lobes. The adjustment mechanism is configured to change a distance between the blade tip and the shroud inner surface by lengthening or shortening a distance between at least a portion of the shroud inner surface and the central axis.
The adjustment mechanism may include an inflatable bladder coupled with the shroud inner surface and configured to change a distance between at least a portion of the shroud inner surface and the central axis upon inflation or upon deflation of at least a portion of the inflatable bladder. The adjustment mechanism may include a hinged pitch mechanism.
In one example embodiment, an energy extraction shrouded fluid turbine includes a rotor and a first shroud. The rotor includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine. The rotor also includes a blade with a proximal portion including a blade root coupled to the central hub, a distal portion including a blade tip, and a mid-portion disposed between the proximal portion and the distal portion. The first shroud includes an inner surface in proximity to the blade tip and mixing lobes. The inner surface has a radial groove into which the blade tip extends during rotation of the rotor. In one example embodiment, the energy extraction shrouded fluid turbine may also include a second shroud downstream of the first shroud. The second shroud and may be an ejector shroud.
The groove may be at least partially formed through abrasion of the shroud inner surface by the blade tip. The rotor may further include a blade ring coupled to the distal portion of the blade, extending circumferentially about the central axis and extending at least partially into the groove.
In another example embodiment, an energy extraction shrouded fluid turbine includes a rotor and a first shroud. The rotor includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine. The rotor also includes a blade with a proximal portion including a blade root coupled to the central hub, a distal portion including a blade tip, and a mid-portion disposed between the proximal portion and the distal portion. The first shroud includes an inner surface in proximity to the blade tip and mixing lobes. The inner surface includes an abradable material having a hardness less than a hardness of the blade tip. The blade tip may occasionally contact the inner surface during rotation of the rotor. The blade tip may include an abrasive material having a hardness greater than a hardness of a mid-portion of the blade. In one example embodiment, the energy extraction shrouded fluid turbine may also include a second shroud downstream of the first shroud. The second shroud and may be an ejector shroud.
In yet another example embodiment, an energy extraction shrouded fluid turbine includes a rotor, a first shroud and may include an ejector shroud located downstream from the first shroud. The rotor includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine. The rotor also includes a blade with a proximal portion including a blade root coupled to the central hub, a distal portion including a blade tip, and a mid-portion disposed between the proximal portion and the distal portion. The rotor further includes a blade ring extending circumferentially about the central axis and coupled to the distal portion of the blade. The first shroud includes an inner surface in proximity to the blade ring and mixing lobes. The inner surface of the first shroud may have a radial groove into which the blade ring at least partially extends.
Other example embodiments may incorporate methods. An example embodiment includes a method of adjusting a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine. The energy extraction shrouded fluid turbine includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, and a first shroud having an inner surface in proximity to the blade tip. The energy extraction shrouded fluid turbine may further include an ejector shroud, and the first shroud may have mixing lobes.
The method includes sensing a spacing between the blade tip and at least a portion of the inner surface of the first shroud during rotation of the blade about the central axis. The method also includes changing a distance between the blade tip and the central hub in response to the sensed spacing.
Sensing the spacing between the blade tip and the shroud inner surface may include detecting a radial position of the blade tip relative to the central axis or relative to the shroud inner surface. Sensing the spacing between the blade tip and the shroud inner surface may include optically detecting a position of the blade tip relative to the central axis or relative to the shroud inner surface.
Changing a distance between the blade tip and the central hub may include changing the distance between the blade tip and the central hub in real-time during operation of the shrouded fluid turbine. Changing a distance between the blade tip and the central hub may include extending or retracting at least a portion of the blade with respect to the central hub. At least a portion of the blade may be extended or retracted telescopically.
Changing a distance between the blade tip and the central hub includes displacing at least the blade tip and the blade mid-portion in a radial direction with respect to the central hub. Changing a distance between the blade tip and the central hub may include rotating at least the distal portion of the blade relative to the proximal portion of the blade, or relative to the central hub about a non-radial axis.
Another example embodiment is a method of controlling a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine. The energy extraction shrouded fluid turbine includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, and a first shroud having an inner surface in proximity to the blade tip. The method includes detecting a spacing between the blade tip and at least a portion of the shroud inner surface during rotation of the blade about the central axis. The method further includes actively controlling a distance between the blade tip and the central hub during rotation of the blade based on the detected spacing. Actively controlling a distance between the blade tip and the central hub during rotation of the blade may include changing the distance between the blade tip and the central hub in real time during operation of the shrouded fluid turbine.
One example embodiment includes a method of adjusting a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine. The energy extraction shrouded fluid turbine includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, and a first shroud having an inner surface in proximity to the blade tip. The first shroud may have mixing lobes and the energy extraction shrouded fluid turbine may further include an ejector shroud downstream of the first shroud.
The method includes sensing a spacing between the blade tip and at least a portion of the inner surface of the first shroud during rotation of the blade about the central axis. The method further includes changing a distance between at least a portion of the shroud inner surface and the central axis based on the detected spacing. Changing a distance between at least a portion of the shroud inner surface and the central axis based on the detected spacing may occur during operation of the energy extraction shrouded fluid turbine and during rotation of the blade.
The energy extraction shrouded fluid turbine further includes an inflatable bladder associated with the shroud inner surface. Changing a distance between at least a portion of the shroud inner surface and the central axis may include inflating or deflating at least a portion of the inflatable bladder.
The energy extraction shrouded fluid turbine may further include a hinged pitch mechanism. The distance between a portion of the shroud inner surface and the central axis may be changed using the hinged pitch mechanism.
Another example embodiment includes a method of controlling a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine. The energy extraction shrouded fluid turbine includes a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, a shroud having inner surface portions in proximity to the blade tip, and a clearance control mechanism. The method includes repelling the blade tip from at least some of the shroud inner surface portions or repelling at least some of the shroud inner surface portion from the blade tip during rotation of the blade about the central axis using the clearance control mechanism.
The blade tip may be magnetically repelled from at least some of the shroud inner surface portions or at least some of the inner surface portions may be magnetically repelled from the blade tip. The clearance control mechanism may include ferromagnetic material disposed in at least one of the blade tip and the first shroud. The clearance control mechanism may include an electromagnet.
Another example embodiment includes a method for controlling a blade tip-shroud spacing. The method includes providing an energy extraction shrouded fluid turbine having a rotor and a first shroud. The rotor has a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine and a blade. The blade includes a proximal portion with a blade root coupled to the central hub, a distal portion including a blade tip and a mid-portion disposed between the proximal portion and the distal portion. The first shroud has an inner surface in proximity to the blade tip with the inner surface including an abradable material having a hardness less than a hardness of the blade tip. The method further includes forming a radial groove or trough in the inner surface of the first shroud by at least intermittent contact with the blade tip upon rotation of the blade.
The summary above is provided merely to introduce a selection of concepts that are further described below in the detailed description. The summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
A more complete understanding of the components, processes, and apparatuses disclosed herein may be obtained by reference to the accompanying figures. These figures are intended to illustrate the teachings taught herein and are not intended to show relative sizes and dimensions, or to limit the scope of examples or embodiments. In the drawings, the same numbers are used throughout the drawings to reference like features and components of like function.
Example embodiments described herein relate to setting, controlling or adjusting a blade tip-to-shroud clearance in a shrouded fluid turbine. In one embodiment of the present invention, a shrouded fluid turbine may include a turbine shroud and rotor with one or more blades that rotate about a central axis of shrouded fluid turbine. A spacing between an inner surface of the turbine shroud and tips of blades of the rotor is referred to as tip-to-shroud (or shroud-tip) clearance or gap.
In shrouded fluid turbines used for energy extraction (e.g., shrouded wind turbines or shrouded hydro turbines power generation), the efficiency of the shrouded fluid turbine may depend, at least in part, on the shroud-tip gap or clearance. Generally, the smaller the gap between the surface of the shroud and the blade tips, the greater the efficiency of the shrouded fluid turbine. During normal operation, a relatively high efficiency, and a correspondingly small shroud-tip gap, is often desirable. However, decreasing the shroud-tip gap size could increase the risk that a blade tip contacts the shroud inner surface during operation, potentially damaging the rotor, the shroud or both. Thus, during normal operation, it may be desirable to have a shroud-tip gap sufficiently small that efficiency is relatively high, but sufficiently large that a risk that a blade tip contacts the shroud inner surface is acceptably small. For an example shrouded fluid turbine, a gap between the rotor tip and shroud that is equal to 0.5% of the inner radius of the shroud may result in a 2% improvement in efficiency as compared to a gap that is 2% of the inner radius of the shroud.
For energy extraction turbines (e.g., wind turbines or hydro turbines for power generation) excessively high fluid flow conditions (e.g., excessively high winds or high water flow rates) may cause electrical damage due to overloading power generation components or cause mechanical damage due to the rotor rotating at excessive speeds. Under excessively high fluid flow conditions it may be desirable to reduce an efficiency of a shrouded fluid turbine to reduce the risk of overloading electrical components and/or to reduce the risk of exceeding structural and mechanical limits of the fluid turbine. Thus, a larger shroud-tip gap, and a correspondingly lower efficiency, may reduce or prevent damage to a shrouded fluid turbine during excessively high fluid flow conditions.
A shroud-tip clearance or gap may be set or adjusted during initial assembly, construction or installation of a shrouded fluid turbine. The shroud-tip gap may need to be periodically adjusted after assembly, construction or installation to correct for changes in the shroud-tip gap or clearance over time. A shroud-tip clearance may change on a short time scale (e.g., dimensional changes caused by differences in thermal expansion of the rotor and of the shroud, or elastic deformation of components under high or variable ambient fluid flows). A shroud-tip clearance may also change on a long time scale (e.g., non-elastic (creep) deformation of components or dimensional changes due to corrosion).
Example embodiments described herein relate to shrouded fluid turbines having features for controlling, setting or adjusting a shroud-tip gap, as well as methods for controlling, setting or adjusting the shroud-tip gap in a shrouded fluid turbine. The features may be incorporated in a fluid turbine that includes only a first shroud, for example, only a mixer shroud. Likewise, the features may be incorporated in a mixer-ejector turbine that includes a first mixer shroud and an ejector shroud downstream of the first mixer shroud.
To facilitate explanation of the Applicant's contribution to the art of shrouded turbines,
The blade tip-shroud clearance concepts described and taught herein are equally applicable to shrouded turbines having a single shroud and shrouded turbines having multiple shrouds.
The turbine shroud 20, which also may be identified herein as a mixer shroud, a mixing shroud or a first shroud, includes a front end 22, also known as an inlet end or a leading edge, and a rear end 24, also known as an exhaust end or trailing edge.
In some embodiments the shrouded fluid turbine 10 also includes a second shroud, such as an ejector shroud 40, downstream of the turbine shroud. As illustrated by
Throughout this disclosure, the front end (inlet or leading edge) of a first shroud (e.g., a turbine shroud) may be considered the front of a shrouded fluid turbine. For a single shroud embodiment, the rear end (exhaust or trailing edge) of the first shroud (e.g., the turbine shroud) may be considered the rear of the shrouded fluid turbine. For a multi-shroud embodiment, the rear end (exhaust or trailing edge) of the shroud furthest downstream (e.g., the ejector shroud or the second shroud) may be considered the rear of the shrouded fluid turbine. A first component located closer to the front of the shrouded fluid turbine may be considered “upstream” of a second component located closer to the rear of the shrouded fluid turbine (e.g., the turbine shroud upstream of the ejector shroud in a multi-shroud embodiment). The second component may be described as “downstream” of the first component (e.g., the ejector shroud downstream of the turbine shroud in a multi-shroud embodiment).
As illustrated by
The term “rotor” is used herein to refer to any component or assembly in which one or more blades are attached to, or coupled with, a shaft and able to rotate, allowing for the extraction of energy or power from a fluid stream flow that rotates the blade(s). Example rotors include, but are not limited to, a propeller-like rotor, an impeller and a rotor/stator assembly. As understood by one skilled in the art, any type of rotor may be used in conjunction with the turbine shroud in a shrouded fluid turbine of the present disclosure.
Although turbine shroud 20 is shown encircling the rotor 60, in some example embodiments the turbine shroud may only partially encircle the rotor (e.g., the turbine shroud may have gaps, or the rotor may extend beyond the leading edge or trailing edge of the turbine shroud). In some embodiments, the turbine shroud may not encircle the rotor (e.g., the rotor may be positioned in front of the leading edge or past the trailing edge of the turbine shroud).
As illustrated by
In embodiments with more than one shroud, the shrouded fluid turbine may be described as a mixer-ejector turbine because the low energy mixing lobes 26 and the high energy mixing lobes 28 of the turbine shroud 20 together with the ejector shroud 40 form a mixer-ejector pump. A shrouded fluid turbine incorporating a mixer-ejector pump may more efficiently extract power from a fluid flow than a shrouded fluid turbine that does not include a mixer-ejector pump. As illustrated by
As noted above, the shrouded fluid turbines of the present disclosure incorporate features for controlling, setting or adjusting the shroud-tip gap DG. The shroud-tip gap DG may be changed by changing a distance between a blade tip and the central hub (e.g., DTH depicted in
As explained above, adjustment mechanisms and shroud-tip clearance features described and depicted herein may be incorporated into shrouded fluid turbines having a single shroud and shrouded fluid turbines having more than one shroud (e.g., mixer-ejector shrouded fluid turbines).
In some embodiments the blade's distal portion, the blade's mid-portion and/or the blade's proximal portion may be continuously adjustable to obtain any position between a fully extended position and a fully retracted position. In other embodiments, the blade's distal portion, the blade's mid-portion and/or the blade's proximal portion may be adjusted to one or more fixed positions between a fully extended position and a fully retracted position. Although in shrouded fluid turbine 110, the distal portion 176 of each blade is extendable and retractable, in some embodiments a distal portion, a mid portion and/or a proximal portion of a blade may be extendable and retractable.
As illustrated by the side cross-sectional view of
One of skill in the art would recognize that extending or retracting a proximal portion of a blade (e.g., proximal portion 176 in
By varying an angular displacement of the distal portion 476 of the blade with respect to the proximal portion 472, a distance between a blade tip 477 and a central hub 462 can be set, adjusted or controlled. As shown in the side cross-section view of
As used herein, the term “blade tip” refers to the portion of the blade that is closest to the shroud inner surface, which may depend on the current configuration of the blade. For example, with the distal portion of the blade aligned with axis 480, the “blade tip” refers to the terminal end portion of the blade. If the distal portion 276 of the blade were angularly displaced by more than 90 degrees with respect to axis 480, the “blade tip” would refer to the hinge 479, which would then be closest to shroud inner surface 425. Similarly, if the distal portion 476 were angularly displaced by more than 90 degrees, the shroud-tip gap or clearance distance would refer to the distance between the hinge 479 and the portion of the inner surface 425 proximal to the hinge.
One of ordinary skill in the art, in view of the described example embodiments, would recognize that many different configurations and structures could be employed to permit a distal portion of a blade to rotate about a non-radial axis with respect to a proximal portion of the blade. Although
Although
An inflatable bladder, (e.g., inflatable bladder 580 or
An inflatable bladder may be coupleable to, affixed to or integral with a non-inflatable portion of the turbine shroud. The inflatable bladder may be removable or replaceable.
The shrouded fluid turbine 710 may include a control mechanism to control the positions of at least some of the inner surface portions relative to the central axis 718. For example, one or more levers 786 may be used to control the tilt of the hinged portions 784, as shown. In some example embodiments the control mechanism may individually and independently control the position of each hinged inner surface portion for a plurality of the inner surface portions. In some example embodiments the control mechanism may control the positions of the hinged inner surface portions as a group.
The shrouded fluid turbine 710 may include one or more sensors 792 for sensing or detecting a spacing between the shroud inner surface 725 and the blade tip 777 or between the shroud inner surface 725 and the central axis 718. The sensors may be optical, electrical, electro-magnetic, mechanical or may employ any other suitable sensing mode.
One of ordinary skill in the art would recognize that other control mechanisms could be employed to adjust a pitch of turbine shroud segments, including, but not limited to rotational actuator motors, torsion bars, linear motorized actuators, pneumatic or hydraulic pistons and the like.
As noted above, some example embodiments of shrouded fluid turbines include structures that may reduce the potential for destructive shroud-tip contact and/or that may reduce an effect of the shroud-tip gap on efficiency of the shrouded wind turbine.
A shroud-tip clearance or gap is defined between an outer surface of the blade ring 864 and inner surface 825 of the turbine shroud at the recess 882. A size of the shroud-tip gap may have a reduced effect on efficiency of the shrouded fluid turbine 810 because fluid flowing through the gap cannot flow along a straight path, but instead must flow into the recess 882, around the blade ring 864 and out of the recess 882.
The blade ring 864 provides some mechanical support to the blade tips 877 and may reduce the amount that the blades 870 elastically or plastically deform, which may reduce the chance of incidental contact with the inner surface 825 of the turbine shroud 820. Further, the potential for destructive contact between the rotor 860 and the turbine shroud 820 may be reduced because incidental contact between the rotor 860 and the turbine shroud 820 occurs at the blade ring 864 instead of at tips of individual unsupported blades.
Some example embodiments may incorporate a blade ring that fully extends into a radial recess of a turbine shroud, or a blade ring that only partially extends into a radial recess of a turbine shroud. Some example embodiments may incorporate a blade ring, but not a radial recess in the turbine shroud. Some example embodiments may incorporate a radial recess in the turbine shroud without a blade ring.
In other embodiments, an inner shroud surface may comprise a high hardness material or an abrasive high hardness material and a blade tip may comprise an abradable material. In these embodiments, during use, intermittent or continuous contact between the blade tip and the inner shroud surface would abrade the blade tip.
The abradable shroud inner surface or the abradable blade tip may comprise a foam, a foam with a thin skin of fiber reinforced polymer (FRP), or another suitable material. A hard abrasive blade tip or a hard abrasive shroud inner surface may comprise a structural FRP additionally impregnated with a granular substance, such as sand or metal filings, that would make a rough surface to wear away the abradable material.
Some shrouded fluid turbines may include a clearance control mechanism that repels a blade tip from at least some of the shroud inner surface portions or that repels at least some of the shroud inner surface portions from the blade tip. For example,
Although turbine shroud 1320 in
As illustrated by
Some example embodiments are directed to methods that employ shrouded fluid turbines.
For illustrative purposes, method 2000 is described with respect to the shrouded fluid turbine 110 depicted in
Method 2000 includes sensing a spacing between the blade tip 177 and at least a portion of the inner surface 125 of the turbine shroud during rotation of the blade about the central axis (method portion 2002). Sensing the spacing between the blade tip 177 and at least a portion of the inner surface 125 of the turbine shroud 120 may include detecting a radial position of the blade tip 177 relative to the central axis 118, relative to the central hub 162, or relative to the shroud inner surface 125. The spacing between the blade tip 177 and at least a portion of the shroud inner surface 125 may be sensed optically, electrically, electromagnetically, mechanically or using any other suitable sensing mode.
Method 2000 also includes changing a distance DTH between the blade tip 177 and the central hub 162 in response to the sensed spacing (method portion 2004). Changing a distance between the blade tip and the central hub may include extending or retracting at least a portion of the blade with respect to the central hub (see e.g., detail 101 of
Changing a distance between the blade tip and the central hub may include rotating at least the distal portion of the blade relative to the proximal portion of the blade, or relative to the central hub, about a non-radial axis (see, e.g.,
Method 2010 includes sensing a spacing between the blade tip 577 and at least a portion of the inner surface 525 of the turbine shroud 520 during rotation of the blade 570 about the central axis 518 (method portion 2012). Sensing the spacing between the blade tip 577 and at least a portion of the inner surface 525 of the turbine shroud 520 may include detecting a radial position of the blade tip 577 relative to the central axis 518 or relative to the shroud inner surface 525, or detecting a radial position of at least a portion of the shroud inner surface 525 relative to the central axis 518. The spacing between the blade tip 577 and at least a portion of the shroud inner surface 525 may be sensed optically, electrically, electromagnetically, mechanically or using any other suitable sensing mode.
Method 2010 also includes changing a distance between at least a portion of the shroud inner surface 525 and the central axis 518 based on the sensed spacing (method portion 2014). Changing a distance between at least a portion of the shroud inner surface 525 and the central axis 518 may occur during operation of the energy extraction turbine and during rotation of the blade 570.
The energy extraction shrouded fluid turbine may further include an inflatable bladder associated with the shroud inner surface (see e.g., inflatable bladder 580 of
The energy extraction shrouded fluid turbine may further include a hinged pitch mechanism (see e.g.,
Method 2020 includes detecting a spacing between the blade tip 177 and at least a portion of the shroud inner surface 125 during rotation of the blade 170 about the central axis 162 (method portion 2022). Method 2020 also includes actively controlling a distance between the blade tip 177 and the central hub 162 during rotation of the blade 170 based on the detected spacing (method portion 2024). Actively controlling a distance between the blade tip and the central hub during rotation of the blade may include changing the distance between the blade tip and the central hub in real-time during operation of the shrouded fluid turbine (see, e.g.,
Actively controlling a property implies calculating, measuring, sensing or determining one or more parameters of a system and changing or maintaining a physical and/or electromagnetic property of the system in response to the one or more calculated, measured, sensed or determined parameters to obtain or maintain a desired value of the controlled property. Passively controlling a property implies that the system itself adjusts to maintain a desired property, but the adjustment is not in response to a calculated, measured, sensed or determined parameter.
Method 2030 includes detecting a spacing between the blade tip 777 and at least a portion of the shroud inner surface 725 during rotation of the blade 770 about the central axis 762 (method portion 2032). Method 2030 also includes actively controlling a distance between at least a portion of the shroud inner surface 725 and the central axis 762 during rotation of the blade 770 based on the detected spacing (method portion 2024); however, one of skill in the art will recognize that method 2030 may be implemented using other configurations of shrouded fluid turbines that have features for actively controlling a distance between a blade tip and at least a portion of a shroud inner surface based on a detected spacing. For example, method 2030 may be employed using any of the shrouded fluid turbines in
The shrouded fluid turbine may include an inflatable bladder (see e.g., inflatable bladder 580 of
The energy extraction shrouded fluid turbine may further include a hinged pitch mechanism (see e.g.,
Method 2040 includes repelling the blade tip 1077 from at least some of the shroud inner surface portions 1025 or repelling at least some of the shroud inner surface portions 1025 from the blade tip 1077 during rotation of the blade 1070 about the central axis 1018 using the clearance control mechanism (method portion 2042). The clearance control mechanism may include ferromagnetic material (e.g., magnets 1082) disposed in at least one of the blade tip 1077 and the turbine shroud 1020. The clearance control mechanism may include electromagnets. The blade tip 1077 may be repelled from at least some of the shroud inner surface portions 1025, or at least some of the inner surface portions 1025 may be magnetically repelled from the blade tip 1077.
Method 2050 also includes forming a radial groove or trough 986 in the inner surface 925 of the turbine shroud 920 by at least intermittent contact with the blade tip 977 upon rotation of the blade 977. The radial groove or trough 986 may be formed, at least in part, before installation of the shrouded fluid turbine, may be formed at least in part, during installation of the shrouded fluid turbine, and/or may be formed, at least in part, during use of the shrouded fluid turbine.
The example shrouded fluid turbines described herein may be incorporated into a shrouded fluid turbine system that includes controllers for controlling one or more fluid turbines. One or more shrouded fluid turbine systems may, in turn, form a portion of a larger shrouded fluid turbine array system for decentralized energy generation.
The example embodiments may be utilized in conjunction a variety of forms of decentralized energy resources. One skilled in the art will recognize that the fluid turbine arrangements may be utilized in the generation of power in conjunction with overall power production in large-scale power grids. To ensure stable and controllable power production the shrouded fluid turbines may be interfaced with the power grid in a variety of suitable ways. One suitable approach for controlling and monitoring the output of a shrouded fluid turbine array system is a Supervisory Control And Data Acquisition (SCADA) system. A SCADA system for use with a shrouded fluid turbine array typically includes input/output signal hardware and controllers at the various location(s) to be monitored and/or controlled, a SCADA hub for monitoring and controlling the location(s), a communication link(s) from the location(s) to the SCADA hub, and one or more supervisory stations at location(s) remote from the SCADA hub and in communication with the SCADA hub.
As schematically represented in
Turbine control device 2100 includes one or more computer-readable media for storing one or more computer-executable instructions or software for implementing example embodiments. For example, a memory 2106 of the turbine control device 2100 may store computer-executable instructions or software, e.g., instructions for implementing and processing every module of the executable turbine control code 2150. The computer-readable media may include, but are not limited to, one or more types of hardware memory, non-transitory tangible media, etc. The memory 2106 may comprise a computer system memory or random access memory, such as DRAM, SRAM, EDO RAM, etc. The memory 2106 may comprise other types of memory as well, or combinations thereof. The turbine control device 2100 may also include, or be in communication with, computer readable storage 2116 (e.g., a hard-drive, CD-ROM, or other non-transitory computer readable media) which may store the turbine control code 2150 and an operating system 2118.
The turbine control device 2100 includes a processor 2102, and may include one or additional more processor(s) 2103, for executing software stored in the memory 2106 and other programs for controlling system hardware. The processor 2102 and additional processor(s) 2103 may each have one or more core processors 2104 and 2105.
Virtualization may be employed in turbine control device 2100 so that infrastructure and resources in the computing device can be shared dynamically. Virtualized processors may also be used with the executable turbine control code 2150 and other software in storage 2116. A virtual machine 2114 may be provided to handle a process running on multiple processors so that the process appears to be using only one computing resource rather than multiple. Multiple virtual machines can also be used with one processor.
A user or operator of the shrouded fluid turbine system, or shrouded fluid turbine array system, may interact with the turbine control device 2100 through a visual display device 2122, such as a computer monitor, which may display the user interface 2124 or any other interface. The visual display device 2122 may also display other aspects or elements of example embodiments, (e.g., control and performance information regarding individual shrouded fluid turbines, control and performance information regarding the array of shrouded fluid turbines, information regarding the interface with the power grid). The turbine control device 2100 may include other I/O devices such a keyboard or a multi-point touch interface 2108 (e.g., a touch screen or touchpad), and a pointing device 2110, (e.g., a mouse or optical trackball) for receiving input from a user. The keyboard 2108 and the pointing device 2110 may be connected to the visual display device 2122. The turbine control device 2100 may include other suitable conventional I/O peripherals.
Turbine control device 2100 may include a network interface 2112 to interface to a Local Area Network (LAN), Wide Area Network (WAN) or the Internet through a variety of connections including, but not limited to, standard telephone lines, LAN or WAN links (e.g., 802.11, T1, T3, 56kb, X.25), broadband connections (e.g., ISDN, Frame Relay, ATM), wireless connections, controller area network (CAN), or some combination of any or all of the above. The network interface 2112 may comprise a built-in network adapter, network interface card, PCMCIA network card, card bus network adapter, wireless network adapter, USB network adapter, modem or any other device suitable for interfacing turbine control device 2100 to any type of network capable of communication and performing the operations described herein. Moreover, control device 2100 may be any computer system such as a workstation, desktop computer, server, laptop, handheld computer or other form of computing or telecommunications device that is capable of communication and that has sufficient processor power and memory capacity to perform the operations described herein. In some embodiments, one or more remote servers(s) may perform at least some processing for a user or operator using a local device to communicate with the remote server(s).
Turbine control device 2100 can be running any operating system such as any of the versions of the Microsoft® Windows® operating system, the different releases of the Unix and Linux operating systems, any version of the MacOS® operating system, any embedded operating system, any real-time operating system, any open-source operating system, any proprietary operating system, any operating systems for mobile computing devices, any internet delivered or internet based operating systems, or any other operating system capable of running on a computing device and performing the operations described herein. The operating system may be running in native mode or emulated mode.
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this disclosure. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
The term “about” when used with a quantity includes the stated value and also has the meaning dictated by the context. For example, it includes at least the degree of error associated with the measurement of the particular quantity. When used in the context of a range, the term “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the range “from about 2 to about 4” also discloses the range “from 2 to 4.”
In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
Claims
1. A shrouded fluid turbine comprising:
- a central hub rotatable about a central axis of the shrouded fluid turbine;
- a blade comprising: a proximal portion including a blade root coupled to the central hub; a distal portion including a blade tip; and a mid-portion disposed between the proximal portion and the distal portion;
- a first shroud having an inner surface in proximity to the blade tip; and
- an adjustment mechanism configured to adjust a separation between the blade tip and the shroud inner surface by lengthening or shortening a distance between the blade tip and the central hub.
2. The shrouded fluid turbine of claim 1, further comprising an ejector shroud located downstream from the first shroud; wherein the first shroud comprises mixing lobes.
3. The shrouded fluid turbine of claim 1, wherein the adjustment mechanism radially retracts or extends at least a portion of the blade with respect to the central hub.
4. The shrouded fluid turbine of claim 3, wherein the adjustment mechanism retracts or extends at least a portion of the blade telescopically.
5. The shrouded fluid turbine of claim 1, wherein the adjustment mechanism displaces at least the distal portion and the mid-portion of the blade in a radial direction with respect to the central hub.
6. The shrouded fluid turbine of claim 1, wherein the adjustment mechanism comprises a coupling between at least the distal portion of the blade and the proximal portion of the blade that permits at least the distal portion of the blade to be rotationally displaced about a non-radial axis relative to the proximal portion of the blade.
7. The shrouded fluid turbine of claim 6, wherein the adjustment mechanism comprises a hinge coupling the distal portion of the blade and the proximal portion of the blade.
8. The shrouded fluid turbine of claim 1, wherein the adjustment mechanism comprises a hinged coupling that permits at least the proximal portion of the blade to be angularly displaced about a non-radial axis relative to the central hub.
9. A shrouded fluid turbine comprising:
- a central hub rotatable about a central axis of the shrouded fluid turbine;
- a blade comprising: a proximal portion including a blade root coupled to the central hub; a distal portion including a blade tip; and a mid-portion disposed between the proximal portion and the distal portion;
- a first shroud having an inner surface in proximity to the blade tip; and
- an inflatable bladder associated with the inner surface and configured to change a spacing between the blade tip and the inner surface by changing a distance between at least a portion of the inner surface and the central axis upon inflation or upon deflation of at least a portion of the inflatable bladder.
10. The shrouded fluid turbine of claim 9, further comprising an ejector shroud located downstream from the first shroud; wherein the first shroud comprises mixing lobes.
11. The shrouded fluid turbine of claim 9, wherein the inflatable bladder is coupleable to the first shroud.
12. The shrouded fluid turbine of claim 9, wherein the inflatable bladder is integral to the first shroud.
13. The shrouded fluid turbine of claim 9, wherein the inflatable bladder comprises a plurality of inflatable chambers.
14. A shrouded fluid turbine comprising:
- a central hub rotatable about a central axis of the shrouded fluid turbine;
- a blade comprising: a proximal portion including a blade root coupled to the central hub; a distal portion including a blade tip; and a mid-portion disposed between the proximal portion and the distal portion;
- a first shroud having inner surface portions in proximity to the blade tip; and
- a hinged pitch mechanism configured to lengthen or shorten a distance between at least some of the inner surface portions of the first shroud and the central axis.
15. The shrouded fluid turbine of claim 14, further comprising an ejector shroud located downstream from the first shroud; wherein the first shroud comprises mixing lobes.
16. The shrouded fluid turbine of claim 14, further comprising a control mechanism to control the positions of at least some of the inner surface portions relative to the central axis.
17. The shrouded fluid turbine of claim 16, wherein the control mechanism individually controls the position of each inner surface portion for a plurality of the inner surface portions.
18-22. (canceled)
23. An energy extraction shrouded fluid turbine comprising:
- a rotor having a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine;
- a blade having: a proximal portion including a blade root coupled to the central hub; a distal portion including a blade tip; and a mid-portion disposed between the proximal portion and the distal portion;
- a first shroud having: an inner surface in proximity to the blade tip; and mixing lobes; and
- an adjustment mechanism configured to change a distance between the blade tip and the shroud inner surface by lengthening or shortening a distance between at least a portion of the shroud inner surface and the central axis.
24. The energy extraction shrouded fluid turbine of claim 23, further comprising an ejector shroud located downstream from the first shroud.
25. The energy extraction shrouded fluid turbine of claim 23, wherein the adjustment mechanism comprises an inflatable bladder coupled with the shroud inner surface and configured to change a distance between at least a portion of the shroud inner surface and the central axis upon inflation or upon deflation of at least a portion of the inflatable bladder.
26. The energy extraction shrouded fluid turbine of claim 23, wherein the adjustment mechanism comprises a hinged pitch mechanism.
27.-39. (canceled)
40. A method of adjusting a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine including a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, and a first shroud having an inner surface in proximity to the blade tip, the method comprising:
- sensing a spacing between the blade tip and at least a portion of the inner surface of the first shroud during rotation of the blade about the central axis; and
- changing a distance between the blade tip and the central hub in response to the sensed spacing.
41. The method of claim 40, wherein the energy extraction shrouded fluid turbine further includes an ejector shroud; and wherein the first shroud has mixing lobes.
42. The method of claim 40, wherein sensing the spacing between the blade tip and the shroud inner surface comprises detecting a radial position of the blade tip relative to the central axis or relative to the shroud inner surface.
43. The method of claim 40, wherein sensing the spacing between the blade tip and the shroud inner surface comprises optically detecting a position of the blade tip relative to the central axis or relative to the shroud inner surface.
44. The method of claim 40, wherein changing a distance between the blade tip and the central hub comprises changing the distance between the blade tip and the central hub in real time during operation of the shrouded fluid turbine.
45. The method of claim 40, wherein changing a distance between the blade tip and the central hub comprises extending or retracting at least a portion of the blade with respect to the central hub.
46. The method of claim 40, wherein the at least a portion of the blade is extended or retracted telescopically.
47. The method of claim 40, wherein changing a distance between the blade tip and the central hub comprises displacing at least the blade tip and the blade mid-portion in a radial direction with respect to the central hub.
48. The method of claim 40, wherein changing a distance between the blade tip and the central hub comprises rotating at least the distal portion of the blade relative to the proximal portion of the blade about a non-radial axis.
49. The method of claim 40, wherein changing a distance between the blade tip and the central hub comprises rotating at least the distal portion of the blade relative to the central hub about a non-radial axis.
50. A method of controlling a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine including a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, and a first shroud having an inner surface in proximity to the blade tip, the method comprising:
- detecting a spacing between the blade tip and at least a portion of the shroud inner surface during rotation of the blade about the central axis; and
- actively controlling a distance between the blade tip and the central hub during rotation of the blade based on the detected spacing.
51. The method of claim 50, wherein actively controlling a distance between the blade tip and the central hub during rotation of the blade comprises changing the distance between the blade tip and the central hub in real time during operation of the shrouded fluid turbine.
52. A method of adjusting a blade tip-shroud gap spacing in an energy extraction shrouded fluid turbine including a central hub rotatable about a central axis of the energy extraction shrouded fluid turbine, a blade having a blade tip, and a first shroud having an inner surface in proximity to the blade tip, the method comprising:
- sensing a spacing between the blade tip and at least a portion of the inner surface of the first shroud during rotation of the blade about the central axis; and
- changing a distance between at least a portion of the shroud inner surface and the central axis based on the sensed spacing.
53. The method of claims 52, wherein the first shroud has mixing lobes, and wherein the energy extraction shrouded fluid turbine further includes an ejector shroud downstream of the first shroud.
54. The method of claim 52, wherein changing a distance between at least a portion of the shroud inner surface and the central axis based on the detected spacing occurs during operation of the energy extraction shrouded fluid turbine and during rotation of the blade.
55. The method of claim 52, wherein the energy extraction shrouded fluid turbine further includes an inflatable bladder associated with the shroud inner surface, and wherein changing a distance between at least a portion of the shroud inner surface and the central axis comprises inflating or deflating at least a portion of the inflatable bladder.
56. The method of claim 52, wherein the energy extraction shrouded fluid turbine further includes a hinged pitch mechanism, and wherein the distance between the at least a portion of the shroud inner surface and the central axis is changed using the hinged pitch mechanism.
57.-61. (canceled)
Type: Application
Filed: Sep 26, 2012
Publication Date: Aug 1, 2013
Applicant: FloDesign Wind Turbine Corp. (Waltham, MA)
Inventor: FloDesign Wind Turbine Corp. (Waltham, MA)
Application Number: 13/627,361
International Classification: F01D 5/22 (20060101);