WO2018093398A1 - Demi-carénage de turbine à fluide et conception de double ailette de pale de rotor associée - Google Patents

Demi-carénage de turbine à fluide et conception de double ailette de pale de rotor associée Download PDF

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Publication number
WO2018093398A1
WO2018093398A1 PCT/US2016/064249 US2016064249W WO2018093398A1 WO 2018093398 A1 WO2018093398 A1 WO 2018093398A1 US 2016064249 W US2016064249 W US 2016064249W WO 2018093398 A1 WO2018093398 A1 WO 2018093398A1
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WO
WIPO (PCT)
Prior art keywords
rotor
semi
winglet
rotor blade
airfoil
Prior art date
Application number
PCT/US2016/064249
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English (en)
Inventor
William Scott Keeley
Original Assignee
William Scott Keeley
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by William Scott Keeley filed Critical William Scott Keeley
Priority to CA3043544A priority Critical patent/CA3043544A1/fr
Publication of WO2018093398A1 publication Critical patent/WO2018093398A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/04—Wind motors with rotation axis substantially parallel to the air flow entering the rotor  having stationary wind-guiding means, e.g. with shrouds or channels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/0608—Rotors characterised by their aerodynamic shape
    • F03D1/0633—Rotors characterised by their aerodynamic shape of the blades
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/20—Rotors
    • F05B2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05B2240/307—Blade tip, e.g. winglets
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

Definitions

  • the present disclosure relates to shrouded and ducted fluid turbines and to fluid turbine rotor blade design.
  • horizontal axis fluid turbine rotor blades comprise two to five blades arranged evenly about a central axis and coupled to an electrical generation machine.
  • a fluid turbine structure with, for example, an open unshrouded rotor design captures energy from a fluid stream that is smaller in diameter than the rotor.
  • an open unshrouded rotor fluid turbine as fluid flows from the upstream side of the rotor to the downstream side, the average axial fluid velocity remains constant as the flow passes through the rotor plane. Energy is extracted at the rotor resulting in a pressure drop on the downstream side of the rotor.
  • the fluid directly downstream of the rotor consists of air that exists at sub-atmospheric pressure due to the energy extraction.
  • the fluid directly upstream of the rotor consists of air that exists at greater than atmospheric pressure.
  • the high pressure upstream of the rotor deflects some of the upstream air around the rotor. In other words, a portion of the fluid stream is diverted around the open rotor as if by an impediment. As the fluid stream is diverted around the open rotor, it expands, which is referred to as flow expansion at the rotor. Due to the flow expansion, the upstream area of the fluid flow is smaller than the area of the rotor.
  • the Betz limit calculates the maximum power that can be extracted from a volume of moving fluid by an open blade, horizontal axial flow turbine, otherwise referred to as an open-rotor turbine.
  • the Betz limit is derived from fluid dynamic control-volume theory for flow passing through an open rotor. According to the Betz limit, and independent of the design of the fluid turbine, a maximum of 16/27 of the total kinetic energy in a volume of moving fluid can be captured by an open-rotor turbine. Conventional turbines commonly produce 75% to 80% of the Betz limit, or about 44% of the total kinetic energy in a volume of moving fluid.
  • a fluid turbine power coefficient (Cp) is the power generated over the ideal power available by extracting all the wind kinetic energy approaching the rotor area.
  • the Betz power coefficient of 16/27 is the maximum power generation possible based on the kinetic energy of the flow approaching a rotor swept area.
  • the rotor swept area used in the Betz Cp derivation is the system maximum flow area described by the diameter of the rotor blades. The maximum power generation occurs when the rotor flow velocity is the average of the upstream and downstream velocity. This is the only rotor velocity that allows the flow-field to be reversible, and the power extraction to be maximized.
  • the rotor velocity is 2/3 the wind velocity
  • the wake velocity is 1/3 the wind velocity
  • the rotor flow has a non-dimensional pressure coefficient of -1/3 at the rotor exit.
  • the -1/3 pressure coefficient is a result of the rotor wake flow expanding out to twice the rotor exit area downstream of the rotor station.
  • Induced drag is generated by a rotor blade due to the redirection of fluid during the generation of lift as a column of fluid flows through the rotor plane.
  • the redirection of the fluid may include span-wise flow along the pressure side of the rotor blade along a radial direction toward the blade tip where the fluid then flows over to the opposite side of the blade.
  • the fluid flow over the blade tips joins a chord-wise flow, otherwise referred to as bypass flow, forming rotor-tip vortices.
  • the rotor-tip vortices mix with vortices shed from the trailing edge of the rotor blade to form the rotor wake.
  • a shrouded turbine When a shrouded turbine is used for increased power extraction, in general, it extracts more power from the fluid stream than an open rotor by increasing the mass flow through the rotor plane, employing specially designed rotor blades to extract more power than their open-rotor turbine counterpart, and then by dissipating the wake to avoid diffuser stall. Diffuser stall occurs when the increased mass flow through the rotor encounters the ambient fluid stream down-stream of the rotor plane and causes a back-pressure at the rotor plane.
  • Proposed solutions to diffuser stall include: increasing the size of the wake area to allow for increased wake expansion; and injecting high-energy fluid into the rotor wake. Both solutions have been proven to allow for increased energy extraction at the rotor.
  • shrouded turbines have some significant drawbacks.
  • Shrouded turbines are heavier than their open rotor counterparts, they are more expensive to produce and construct, and they create a bluff body when hit by commonly occurring side winds and gusts. Side winds produce a large amount of drag force that places considerable strain on structural components.
  • Wind shear is the difference in wind speed by height. The higher the wind shear, the higher the wind velocity at the upper region of a rotor plane compared with the wind velocity at the lower regions of the rotor plane. As turbines increase in scale, they take advantage of higher wind velocities at higher altitudes while also experiencing greater wind shear. Extreme wind shear is also responsible for worst case noise emissions that are likely to be out of compliance with existing noise pollution regulations,
  • Noise caused by wind turbines is also a product of the wind velocity and the rotor blade trailing-edge and tip vortices. Trailing-edge and tip vortices create a random noise of similar decibel level, otherwise referred to as white-noise.
  • Tower signature is a term often used to describe the sound created as rotor tip vortices encounter the turbine tower. The tower interrupts the flow of the trailing-edge and tip vortices, occurring as each blade passes the tower introducing a pattern, interrupting the random sound, and creating white noise. As the tower interrupts the vortices, it creates a low-frequency tonal signal of sharply rising and falling pulses.
  • the tip-speed ratio is the ratio between the tangential speed of the rotor blade tip and the actual wind velocity. This is expressed by the following formula:
  • the tip-speed can also be calculated as ⁇ times R, where ⁇ is the rotor rotational speed in radians/second, and R is the rotor radius in meters. This is expressed in the following formula: [0017]
  • the tip-speed ratio is an indicator of the efficiency of the turbine.
  • the power coefficient, Cp is a quantity that expresses the fraction of the power in the wind that is being extracted by the turbine.
  • P E is the total energy extracted by a rotor and P w is the total power in the column of wind that is the velocity of the wind and the diameter of the rotor.
  • a fluid power coefficient (Cp) is a function of the power generated by the turbine and the total power available in the column of fluid that is the diameter of the rotor plane and the velocity of the fluid.
  • the efficiency of a mechanical generator is less than 100%;
  • a rotor blade tip that interacts with the high speed flow over a diffuser, also referred to as a semi -annular airfoil or semi-diffuser, which occupies between 10% and 50% of the rotor swept area of a fluid turbine.
  • a rotor blade tip is designed to both improve rotor tip speed and also to increase the beneficial interaction between a diffuser and a rotor blade.
  • a dual tip on each rotor blade is designed to take advantage of a high rotor thrust coefficient, providing reduced coefficient of pressure in the rotor-wake and a high flow stream for increased mixing of rotor-wake flow with bypass flow at the exit plane of the rotor.
  • the fluid power coefficient (Cp) as a function of wake velocity ratio and thrust coefficient (Ct) may be increased because of the low exit-plane pressure coefficient that allows for a relatively higher rotor-thrust coefficient.
  • the rotor design may take advantage of a highly cambered rotor shaft, designed for a greater Cp without stalling as it would without the dual winglet in combination with a semi-shroud.
  • a ringed airfoil surrounding a rotor swept area increases the mass flow through the rotor plane. This increased mass flow must be returned to ambient fluid stream flow rates in order to prevent diffuser stall.
  • a diffuser segment that occupies less than the whole rotor swept area creates two wake flow conditions. One portion of the rotor wake is similar to an open rotor turbine, the remaining portion flows over the diffuser and has a lower energy flow downstream of the rotor than that of the open rotor fluid stream. As the two wake streams mix, the rotor wake will return to ambient flow conditions with sufficient rapidity to avoid diffuser stall.
  • Diffuser airfoil cross sections that occupy only a portion of a rotor plane may be designed with considerably higher camber and, therefore, higher lift coefficients than those designed to occupy the entire rotor swept area.
  • the relatively higher lift coefficient over the semi-shroud increases tip-speed ratio for any rotor.
  • a rotor without a winglet experiences an increase in tip-speed ratio between 12% and 18% whereas a rotor with a winglet designed to interact with the region of increased mass flow over a semi-shroud airfoil experiences an increase in tip-speed ratio that is between 15% and 25% over that of the same rotor without a semi -shroud.
  • tip clearance The gap between the rotor blade tip and the turbine shroud is referred to as tip clearance.
  • Smaller tip clearance is associated with increased effect of the shroud on the rotor.
  • Excessively small tip clearance can result in rotor-shroud interference that can damage both rotor blades and electrical generation equipment.
  • Applying significantly high camber airfoil cross sections and relatively higher lift coefficients in the tip regions of a semi-shroud results in an area of greatest mass flow at the tip regions of the semi-shroud. Therefore, it is possible to have a larger tip clearance at the ends of the semi-shroud than at the center of the semi-shroud.
  • the area of greatest mass flow at the tip region of the semi-shroud guides the rotor tip into alignment with the semi-shroud.
  • an apparatus having a blade tip design that both increases performance in open fluid flow and also increases the performance of a rotor-blade/diffuser interaction.
  • the blade tip interacts with an area of increased mass flow.
  • Increased rotor-blade surface area in the region of increased mass flow increases rotor-blade tip speed.
  • That same rotor-blade surface area is also designed to improve the performance of the rotor blade in open-rotor turbine conditions. Therefore, the same rotor blade performs with significantly increased rotor tip speed and significantly increased coefficient of power in both a diffuser augmented environment and an open-rotor environment.
  • the aerodynamic principles the present disclosure are not restricted to a specific fluid, and may apply to any fluid, defined as any liquid, gas or combination thereof and, therefore, includes water as well as air.
  • the aerodynamic principles of a dual-tip wind rotor blade apply to hydrodynamic principles in a dual-tip water rotor blade.
  • FIG. 1 is front, perspective view of the present embodiment
  • FIG. 2 is a detail, section view of a dual-tip rotor of the present embodiment in combination with a semi-shroud;
  • FIG. 3 is front, perspective view of an iteration of the present embodiment
  • FIG. 4 depicts a rotor blade of the embodiment of FIG 3;
  • FIG. 5 is a detail, section view of a dual -tip rotor of the embodiment of FIG 3 in combination with a semi-shroud;
  • FIG. 6 is front, perspective view of an iteration of the present embodiment
  • FIG. 7 depicts a rotor blade of the embodiment of FIG 6
  • FIG 8 is a detail, section view of a dual -tip rotor of the embodiment of FIG 6 in combination with a semi-shroud;
  • FIG. 9 is front, perspective view of an iteration of the present embodiment.
  • FIG. 10 depicts a rotor blade of the embodiment;
  • FIG. 11 is a detail, section view of a dual -tip rotor of the embodiment on a turbine without a semi-shroud;
  • FIG. 12 is a detail, section view of a dual-tip rotor of the embodiment of FIG 10 in combination with a semi-shroud.
  • Example embodiments of the present disclosure disclose a fixed-blade rotor or a rotor assembly having blades that do not change
  • leading edge of a rotor assembly may be considered the front of the fluid rotor system, and the trailing edge of a rotor assembly may be considered the rear of the fluid rotor system.
  • FIG. 1 presents a front perspective view of a rotor/semi-shroud combination of the present disclosure in situ on a wind turbine.
  • a wind turbine has a tower 114 that is rotationally engaged about a vertical axis 144 with a nacelle 116 that houses electrical generation equipment.
  • a rotor comprised of at least one rotor blade 112 is rotationally engaged about a horizontal axis 146 with the nacelle 116 and electrical generation equipment.
  • a semi-shroud 110 is in fluid communication with the rotor blades 112 and is rotationally engaged with the tower 114 about a rotational alignment means 126.
  • Torsion bars 118 are engaged with both the nacelle 116 and with the semi-shroud 110 and ensure that the semi-shroud rotates about a vertical axis at the same rate as the nacelle 116 to avoid collision between the rotor blades 112 and the semi-shroud 110.
  • a semi-shroud 110 has varying airfoil cross sections, particularly at the semi-shroud tip 111.
  • Varying airfoil cross sections at the semi-shroud tip 111 may have relatively higher camber and relatively higher angle of attack providing a relatively higher lift coefficient than the airfoil cross sections along the majority of the semi-shroud 110.
  • a high lift coefficient will create an area of increased wind velocity for a relatively greater distance from the surface area of the airfoil.
  • the increased lift coefficient and increased wind velocity at a greater distance from the airfoil begins the fluid interaction between the rotor blade and the semi-shroud prior to the rotor blade tip coming into close proximity with the semi-shroud.
  • the varying airfoil cross sections may be designed to create a means of aligning the rotor blade with the semi-shroud using airflow.
  • FIG 2 is a detailed cross section view, depicting the fluid interaction between the rotor blade 112 and the semi-shroud 110 in the vicinity of the center of the semi-shroud 110.
  • Wind approaching a turbine 140 encounters an airfoil cross section of a semi-shroud 120 and divides into a higher velocity stream over the lift surface of the airfoil and a lower velocity, higher pressure flow 141 over the pressure surface of the airfoil.
  • the region depicted by dashed line 128 is a region of increased lift that generates the region of relatively greater mass flow through the rotor plane.
  • the increased mass flow provides increased energy that may be extracted by the rotor as it surrounds the tip of the rotor blade 112 thus increasing the blade tip-speed and the coefficient of power.
  • FIG 3 is an illustration that depicts an iteration of the embodiment having a dual winglet on the tip of each rotor blade 212.
  • Each dual winglet comprises a forward winglet 222 and a rearward winglet 224.
  • the illustration depicts a rotor/semi-shroud combination of the present disclosure in situ on a wind turbine.
  • a wind turbine has a tower 214 that is rotationally engaged about a vertical axis 244 with a nacelle 216 that houses electrical generation equipment.
  • a rotor comprised of at least one rotor blade 212 is rotationally engaged about a horizontal axis 246 with the nacelle 216 and electrical generation equipment.
  • a semi-shroud 210 is in fluid communication with the rotor blades 212 and is rotationally engaged with the tower 214 about a rotational alignment means 226.
  • Torsion bars 218 are engaged with both the nacelle 216 and with the semi-shroud 210 and ensure that the semi-shroud rotates about a vertical axis at the same rate as the nacelle 216 to avoid collision between the rotor blades 212 and the semi-shroud 210.
  • a semi-shroud 210 has varying airfoil cross sections, particularly at the semi-shroud tip 211.
  • airfoil cross sections at the semi-shroud tip 211 may have relatively higher camber and relatively higher angle of attack providing a relatively higher lift coefficient than the airfoil cross sections along the majority of the semi-shroud 210.
  • FIG 4 depicts a rotor of the present disclosure having a dual winglet.
  • the rotor has a primary structure, otherwise referred to as the rotor shaft 240 that extends from the root 238 to the dual tip along a centerline 242.
  • the shaft 240 has a pressure-surface 236 and a lift surface 234 according to the shape of the airfoil cross section.
  • the rotor blade 200 further comprises a pressure-surface winglet 222 and a lift-surface winglet 224.
  • the pressure- surface winglet 222 turns from the pressure-surface 236 to angle 230 that is between 15° and 35° with respect to a centerline 242.
  • FIG. 5 is a detailed cross section view, depicting the fluid interaction between the rotor blade 212 and the semi-shroud 210 in the vicinity of the center of the semi-shroud 210.
  • the rotor blade 212 has a dual winglet tip that has a relatively greater surface area that interacts with the region of high speed flow, otherwise referred to as the area of greater mass flow 228 over the airfoil of the semi-shroud 220.
  • Wind approaching a turbine 240 encounters an airfoil cross section of a semi-shroud 220 and divides into a higher velocity stream over the lift surface of the airfoil and a lower velocity, higher pressure flow 241 over the pressure surface of the airfoil.
  • the region depicted by dashed line 228 is a region of increased lift that generates the relatively greater mass flow through the rotor plane.
  • the increased mass flow provides increased energy that may be extracted by the rotor as it surrounds the dual tip of the rotor blade 212 thus increasing the blade tip-speed and the coefficient of power.
  • Both the pressure surface winglet 222 and the lift surface winglet 224 are substantially inside the area of greater mass flow 228, providing more rotor-blade surface-area in contact with the area of greater mass flow 228, than that of a rotor blade without a winglet such as 112 (FIG. 2).
  • FIG. 6 is an illustration that depicts an iteration of the embodiment having a dual winglet on the tip of each rotor blade 312.
  • Each dual winglet comprises a forward winglet 322 and a rearward winglet 324.
  • the illustration depicts a rotor/semi-shroud combination of the present disclosure in situ on a wind turbine.
  • a wind turbine has a tower 314 that is rotationally engaged about a vertical axis 344 with a nacelle 316 that houses electrical generation equipment.
  • a rotor comprised of at least one rotor blade 312 is rotationally engaged about a horizontal axis 346 with the nacelle 316 and electrical generation equipment.
  • a semi-shroud 310 is in fluid communication with the rotor blades 312 and is rotationally engaged with the tower 314 about a rotational alignment means 326.
  • Torsion bars 318 are engaged with both the nacelle 316 and with the semi-shroud 310 and ensure that the semi-shroud rotates about a vertical axis at the same rate as the nacelle 316 to avoid collision between the rotor blades 312 and the semi-shroud 310.
  • F IG. 7 is an illustration that depicts an iteration of a rotor blade design the embodiment having a dual winglet on the tip of each rotor blade 300.
  • the rotor has a primary structure, otherwise referred to as the rotor shaft 340 that extends from the root 338 to the dual tip along a centerline 342.
  • the shaft 340 has a pressure-surface 336 and a lift surface 334 according to the shape of the airfoil cross sections.
  • the rotor blade 300 further comprises a winglet that transitions arcuately from a pressure-surface portion 322 to a lift- surface portion 324.
  • the pressure-surface portion 322 resides between the centerline 342 and the upwind end of the winglet 322, at an angle 330 that is between 15° and 35° with respect to a centerline 342.
  • the lift-surface portion 332 resides between the centerline 342 and the downwind end of the winglet 324 that is between 70° and 120° with respect to the centerline 342.
  • a point along the arcuate curve of the winglet is tangent with a plane that is
  • the winglet exists in the upwind area and the downwind area with respect to the centerline and that the airfoil cross sections at either end of the arcuate winglet may be similar to those that transition from the lift surface 334 and pressure surface 336 as illustrated in the aforementioned embodiment (FIG. 4) without the separation otherwise referred to as a crease that exists in the
  • FIG. 8 is a detailed cross section view, depicting the fluid interaction between the rotor blade 312 and the semi-shroud 310 in the vicinity of the center of the semi-shroud 310.
  • Wind approaching a turbine 340 encounters an airfoil cross section of a semi-shroud 320 and divides into a higher velocity stream over the lift surface of the airfoil and a lower velocity, higher pressure flow 341 over the pressure surface of the airfoil.
  • the region depicted by dashed line 328 is a region of increased lift that generates the relatively greater mass flow through the rotor plane.
  • the increased mass flow provides increased energy that may be extracted by the rotor as it surrounds the tip of the rotor blade 312 thus increasing the blade tip-speed and the coefficient of power.
  • the tip clearance is the distance between the furthest point of a rotor blade from the rotor center and the surface of the semi-shroud.
  • the tip clearance when a rotor blade is proximal to the center of the semi-shroud is between 0.5% and 3% of the rotor blade length and is illustrated by measurement lines 350.
  • FIG.9 is a front view of the embodiment, illustrating the tip clearance when rotor blades are proximal to the ends of the semi-shroud. Tip clearance at the ends of the semi- shroud is between 1% and 6% of the rotor blade length.
  • FIG. 10 is an illustration that depicts an iteration of a rotor blade design the embodiment having a dual winglet on the tip of a rotor blade 400.
  • the rotor has a primary structure, otherwise referred to as the rotor shaft 440 that extends from the root 438 to the dual tip 430/422 along a centerline 442.
  • the shaft 440 has a pressure-surface 436 and a lift surface 434 according to the shape of the airfoil cross sections.
  • the rotor blade 400 further comprises a first winglet 430 that transitions arcuately from the pressure-surface 436.
  • the pressure-surface winglet 430 resides at an angle 430 that is between 75° and 85° with respect to a centerline 442.
  • FIG. 11 presents a detailed view of a double winglet.
  • the rotor shaft 440 is rotationally engaged at the root 438 with a nacelle 416 shown in section view against a center-line 446.
  • the lift-surface winglet 422 has a lift surface 421 and a pressure surface 423.
  • the pressure surface 423 transitions from the lift surface 434 of the primary shaft 440.
  • the pressure-surface winglet 430 is an airfoil that has a lift side 431 and a pressure side 433.
  • the lift surfaces will create increase velocity when compared to the pressure surface. Two streams are created as the fluid stream encounters each of the winglets.
  • FIG. 12 is a detailed cross section view, depicting the fluid interaction between the rotor blade 412 and the semi-shroud 410 in the vicinity of the center of the semi-shroud 410.
  • Wind approaching a turbine 440 encounters an airfoil cross section of a semi-shroud 420 and divides into a higher velocity stream 440 over the lift surface of the airfoil and a lower velocity, higher pressure flow 441 over the pressure surface of the airfoil.
  • the region depicted by dashed line 428 is a region of increased lift that generates the relatively greater mass flow through the rotor plane.
  • the increased mass flow provides increased energy that may be extracted by the rotor as it surrounds the tip of the rotor blade 412 thus increasing the blade tip-speed ratio and the coefficient of power.
  • the tip clearance is the distance between the furthest point of a rotor blade from the rotor center and the surface of the semi-shroud. Both winglets 430 and 422 interact with the area of increased mass flow 428 and each contributes to the increased tip-speed ratio.
  • the tip clearance when a rotor blade is proximal to the center of the semi-shroud is between 0.5% and 3% of the rotor blade length and is illustrated by measurement lines 350.

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  • Sustainable Development (AREA)
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Abstract

Un profil aérodynamique semi-annulaire est conçu conjointement avec une pale de rotor de turbine à fluide pour fournir une vitesse de pointe de rotor accrue, un coefficient de puissance accru, un cisaillement de vent réduit et un bruit réduit. Une pale de rotor à double ailette en combinaison avec un profil aérodynamique semi-annulaire augmente les avantages mentionnés ci-dessus en augmentant la surface de pointe de pale de rotor qui est en contact avec la zone de vitesse de fluide accrue sur le profil aérodynamique semi-annulaire.
PCT/US2016/064249 2016-11-17 2016-11-30 Demi-carénage de turbine à fluide et conception de double ailette de pale de rotor associée WO2018093398A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA3043544A CA3043544A1 (fr) 2016-11-17 2016-11-30 Demi-carenage de turbine a fluide et conception de double ailette de pale de rotor associee

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US201662423437P 2016-11-17 2016-11-17
US62/423,437 2016-11-17

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100166556A1 (en) * 2008-12-30 2010-07-01 General Electric Company Partial arc shroud for wind turbine blades
US20130309081A1 (en) * 2012-05-17 2013-11-21 Flodesign Wind Turbine Corp. Fluid turbine with rotor upwind of ringed airfoil
US20140169937A1 (en) * 2012-12-18 2014-06-19 Flodesign Wind Turbine Corp. Mixer-ejector turbine with annular airfoils
US20150003994A1 (en) * 2013-06-27 2015-01-01 General Electric Company Wind turbine blade and method of fabricating the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100166556A1 (en) * 2008-12-30 2010-07-01 General Electric Company Partial arc shroud for wind turbine blades
US20130309081A1 (en) * 2012-05-17 2013-11-21 Flodesign Wind Turbine Corp. Fluid turbine with rotor upwind of ringed airfoil
US20140169937A1 (en) * 2012-12-18 2014-06-19 Flodesign Wind Turbine Corp. Mixer-ejector turbine with annular airfoils
US20150003994A1 (en) * 2013-06-27 2015-01-01 General Electric Company Wind turbine blade and method of fabricating the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
MARK J KEELY, SHORT KVSR MEDIUM 5, 13 July 2016 (2016-07-13), Retrieved from the Internet <URL:https://youtu.be/zCVgusrr3vA> [retrieved on 20170320] *

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