WO2014094979A1 - Procédé et moyen pour la réduction de la cavitation dans des convertisseurs d'énergie houlomotrice - Google Patents

Procédé et moyen pour la réduction de la cavitation dans des convertisseurs d'énergie houlomotrice Download PDF

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Publication number
WO2014094979A1
WO2014094979A1 PCT/EP2013/003638 EP2013003638W WO2014094979A1 WO 2014094979 A1 WO2014094979 A1 WO 2014094979A1 EP 2013003638 W EP2013003638 W EP 2013003638W WO 2014094979 A1 WO2014094979 A1 WO 2014094979A1
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WO
WIPO (PCT)
Prior art keywords
movable element
wave energy
cavitation
energy converter
profile
Prior art date
Application number
PCT/EP2013/003638
Other languages
German (de)
English (en)
Inventor
Benjamin Hagemann
Nik Scharmann
Alexander Poddey
Nicolas Houis
Markus Perschall
Jasper Behrendt
Original Assignee
Robert Bosch Gmbh
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.)
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Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2014094979A1 publication Critical patent/WO2014094979A1/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
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/16—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
    • F03B13/18—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore
    • F03B13/1805—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom is hinged to the rem
    • F03B13/1825—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom is hinged to the rem for 360° rotation
    • 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
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/22—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the flow of water resulting from wave movements to drive a motor or turbine
    • 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
    • Y02E10/20—Hydro energy
    • 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
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

  • the present invention relates to a method for cavitation-reduced operation of a wave energy converter, means for implementing such a method and a corresponding operable wave energy converter.
  • Wave energy converters which are arranged with their moving parts under the water surface and exploit a wave orbital motion present there, are of particular interest in the context of the present invention.
  • the wave orbital motion can be converted into a rotational movement by means of rotors.
  • rotors with coupling bodies e.g. hydrodynamic lift profiles.
  • Such a system is disclosed in US 2010/0150716 A1.
  • Rotors with hydrodynamic lift profiles are referred to below as buoyancy runners.
  • cavitation can occur on rapidly moving objects in the water, for example impellers of centrifugal pumps, water turbines or propellers (ship propellers), but also on the lift rotors of wave energy converters, which can lead to a reduction in efficiency and damage.
  • CONFIRMATION COPY Cavitation is the formation and dissolution of vapor or air-filled cavities (bubbles) in liquids, which is caused either by falling below the saturation pressure (degassing of dissolved air) or by falling below the vapor pressure (evaporation of liquid).
  • the steam cavitation falls below the vapor pressure should be considered here.
  • the Bernoulli law the more the velocity of the liquid increases along one streamline (quadratic relationship), the more the total pressure of a liquid drops. If the total pressure falls below the vapor pressure, vaporization and outgassing of the liquid occur. As a result, vapor bubbles formed are entrained in regions of higher pressure, where the total pressure again exceeds the vapor pressure. This condenses the steam in the
  • the present application primarily refers to wave energy converters with buoyancy rotors and the lift profiles built in here, the invention can also be applied to other types of wave energy converters whose moving parts move so fast in the water that cavitation can occur.
  • the pressure distribution around a lift rotor depends, among other things, on the flow velocity, the wing shape and the angle of attack.
  • the typical pressure distribution around buoyancy profile of a buoyancy rotor is illustrated in FIG. 2 and explained in the context of the description of the figures.
  • the present invention proposes a method for cavitation-reduced operation of a wave energy converter, means for implementing such a method and a correspondingly operable wave energy converter with the features of the independent claims.
  • Preferred embodiments are subject matter of the subclaims and the following description.
  • a method for operating a wave energy converter in which a position, position and / or geometry or shape of the at least one movable element is adjusted to avoid cavitation on at least one movable element of the wave energy converter, for example a lift profile.
  • the adjustment takes place so that a total pressure, in particular the minimum total pressure at the surface or in the immediate vicinity of the element, remains above a lower threshold value, in particular the instantaneous vapor pressure.
  • the total pressure is determined on the basis of at least one variable influencing the cavitation at the at least one movable element.
  • the at least one variable influencing the cavitation on the at least one movable element can preferably be detected by detection means, such as sensors.
  • the cavitation slope and the location of possible cavitation events are based on a buoyancy profile, in particular according to the angle of attack (as position of the element) of this profile with respect to an incoming water body.
  • a basically desired suction is generated on one side of the buoyancy profile, which in turn contributes to buoyancy.
  • the suction correlates with the flow velocity (ie relative velocity between water body and profile). In places of maximum suction, therefore, such low total pressures may arise that cavitation occurs.
  • the term "suction tips" is used.
  • the critical area with respect to the formation of corresponding cavitation bubbles is, in the case of a positive angle of attack with respect to the oncoming body of water, the front area of the suction side in the area of the absolute maximum of the suction. At this point, the fluid flowing around the buoyancy profile has the highest flow velocity. The total pressure of the water at this point is reduced to a minimum.
  • the angular velocity of the rotor is largely predetermined.
  • the periods of energy-relevant wavelength range are in a range of 6 to 20 seconds.
  • the flow velocity itself can therefore not be changed.
  • the circumferential radius of the lift profiles around a rotor axis as the position of the element this results in a peripheral speed of the lift profiles with a corresponding relative inflow, which is additionally superimposed on the orbital flow of the wave motion.
  • the essential part of the wing inflow results from the rotational movement of the rotor.
  • High flow velocities, in particular in combination with large flow angles tend to be more critical as this reduces the total pressure on the suction side and thus favors the formation of gas bubbles.
  • the pressure distribution on corresponding profiles in directed flow basically differs from the flow conditions in the real field of application of the wave energy converters.
  • These specific flow conditions can be taken into account by suitable transformation of the profile geometry.
  • a corresponding transformation may include, for example, a curvature of the profile geometry in the chordwise direction corresponding to the circular path described during the revolution.
  • the invention is also suitable for correspondingly transformed profiles.
  • the present invention may also be combined with other measures known per se to avoid cavitation, for example a fluid connection of the pressure with the suction side, air injection and a receding step on the suction side. In this case, for example, an optimization of the airfoils for reducing corresponding suction tips can be done, which can be coupled with a limitation of the rotor diameter. NEN.
  • the adjustment according to the invention of the position, position and / or geometry of the at least one movable element of a wave energy converter, for example a buoyancy profile, comprises a suitable operating strategy for adjusting the angle of attack in order to reduce or prevent excessive suction tips and thus cavitation.
  • the described measures can lead to at least partially reduce the lift coefficients and thus the performance of a corresponding wave energy converter.
  • the present invention still allows overall lower cost of electricity, especially in the offshore area, since typically the maintenance costs are disproportionately included in the electricity production costs.
  • a mixed optimization can also take place in which (slight) cavitation is permitted for certain operating states which are less relevant in terms of time and / or operation and, overall, the best possible energy yield is nevertheless ensured.
  • the invention therefore enables an overall system optimization, within which cavitation is reduced. These operating modes are comprised of a reduced-cavitation operation.
  • An important parameter for reducing or avoiding cavitation is the profile geometry of the buoyancy profiles used. This has a direct effect on the formation of the pressure field around the buoyancy profile.
  • An inventive wave energy converter is therefore advantageously equipped with buoyancy profiles, which have no pronounced suction peaks in the typical operating cases of the wave energy converter.
  • so-called Eppler profiles can be used with particular advantage.
  • profile geometries can also be optimized in the mentioned direction.
  • it may be provided to provide the profile geometry adjustable during operation in order to be able to adapt the profile to different operating states.
  • a corresponding optimization can also, as explained above, initially in directed flow, ie, for example, in a flow channel occur.
  • a correspondingly optimized profile can be optimized with the aid of conformal mapping for the specific application in a wave energy converter with a curved flow.
  • An essential aspect of the present invention is the change of an angle of attack of the at least one movable element in dependence on a Kavitationsne Trent or a corresponding size.
  • the pressure distribution on a symmetrical profile is very strongly dependent on the angle of attack.
  • this also applies to asymmetrical profiles.
  • This behavior can be used to limit the height of the suction tips during operation by suitably adjusting the angle of attack.
  • This can also be done and in particular for a correspondingly optimized profile.
  • a corresponding optimization or optimized activation can also include a control / regulation strategy for the angle of attack with any control target (eg maximum energy yield) to superimpose a control / regulation that reduces the cavitation.
  • cavitation bubbles are formed when the vapor pressure falls below.
  • the locally present depth-dependent hydrostatic pressure of the water is therefore of relevance for the formation of cavitation bubbles.
  • the total pressure is not only dependent on the characteristics of the suction tips, but also on the existing ambient pressure (hydrostatic). With increasing water column above the profile therefore results in a more favorable cavitation. Accordingly, it can be provided in a control / regulation strategy for cavitation reduction to set the angle of attack and / or the shape of the corresponding profile as a function of the prevailing ambient pressure or the height of the water column above the buoyancy profile.
  • an equally important parameter in the formation of cavitation is the inflow velocity of the profile. This depends essentially on the rotor diameter, as explained above. Therefore, according to the invention, it is also possible to set a change in the radius of rotation of the at least one movable element on the wave energy converter so that the rotational speed is reduced at the same rotational speed.
  • An arithmetic unit according to the invention e.g. a drive unit of a wave energy converter, is set up as a means for implementing the method according to the invention, in particular programmatically to carry out the method.
  • Suitable data carriers for providing the computer program are, in particular, floppy disks, hard disks, flash memories, EEPROMs, CD-ROMs, DVDs, and the like. It is also possible to download a program via computer networks (Internet, intranet, etc.).
  • Figure 1 shows the Wellenorbitalterrorismen below the surface of a wavy moving water in a schematic representation.
  • Figure 2 shows the forces acting on a buoyancy profile pressures at a fixed angle in a schematic representation.
  • FIG. 3 shows a schematic representation of the cavitation regions on a buoyancy profile as a function of the angle of attack.
  • Figure 4 shows the profile acting on a buoyancy profile as a function of the angle pressures in a schematic representation.
  • FIG. 5 shows a schematic illustration of a wave energy converter which is set up for an operation according to the invention.
  • FIG. 6 shows the wave energy converter of Figure 5 in a schematic representation to illustrate the inventive measures.
  • FIG. 7 illustrates a method according to an embodiment of the invention in the form of a schematic flow chart.
  • FIG. 1 shows a schematic representation of shaft orbital movements under the surface of a wavy moving water.
  • a wave on the surface of the water is designated 10.
  • the wave propagates in a wave propagation direction 1 1.
  • the mean water surface is designated 12.
  • orbital paths 13 Due to the wave motion below the surface of the water wave orbital movements result in the form of orbital paths 13, which are only partially provided with reference numerals. Immediately below the surface of the water body, these orbital paths 13 each have radii r, which correspond to the amplitude of the shaft 10. The radii decrease with increasing distance to the surface of the water. In deep water, the orbital trajectories 13 are circular, in the shallow water increasingly elliptical.
  • the local water movement is shown schematically in FIG. 1 in the form of short, bold arrows which correspond to the respective motion vectors v.
  • a wave at position A the entirety of the water particles moves in the direction of the wave propagation direction 1.
  • a wave trough at position C the entirety of the water particles moves towards the wave propagation direction 1.
  • position B In the transition from a wave crest (position A) to a wave trough (position C) progressing in the wave propagation direction, at position B there is a situation in which the entirety of the water particles move vertically upward.
  • the entirety of the water particles moves vertically downwards.
  • the inflow direction and the inflow velocity relative to a movable element of a wave energy converter are variables which influence a cavitation or cavitation tendency on this movable element.
  • the movable element can be adjusted based on these quantities.
  • FIG. 2 the pressures acting on a buoyancy profile, for example of a wave energy converter, at a fixed angle of attack are shown schematically in the form of a force diagram 20.
  • the buoyancy profile is designated 3. It is employed in the illustrated example in an angle of attack ⁇ of 5 ° with respect to a direction of flow.
  • the buoyancy profile 3 extends over a length plotted on the x-axis (chord length) from 0 to 1, 0 (relative sizes). It is designed as a symmetrical buoyancy profile 3.
  • the pressure coefficient C p at the top (suction side) and bottom (pressure side) in dimensionless units is indicated on the y-axis.
  • a pressure curve on the suction side of the buoyancy profile is indicated at 21, a pressure curve on the pressure side of the buoyancy profile 3 with 22.
  • the critical region is located with respect to the formation of cavitation bubbles in the front region of the suction side in the region of amount-maximum of the suction-side pressure curve 21, which is also called a suction tip and p in the figure with a C value of about -1, 75 is.
  • the water flowing around the buoyancy profile 3 has the highest flow velocity.
  • the total pressure therefore has its minimum at this point. As explained, this may possibly be below the vapor pressure of the fluid, so that corresponding gas bubbles form.
  • FIG. 3 shows a cavitation diagram of a corresponding buoyancy profile 3 and denotes 30 as a whole.
  • the cavitation number ⁇ 0 is plotted against an angle of attack ⁇ on the x-axis.
  • a cavitation-free region is above the curve 31 and is to be maintained in the adjustment of the angle of attack ⁇ of the lift profile 3 advantageously.
  • a different limit value for the occurrence of cavitation results depending on the angle of attack ⁇ .
  • the location of the greatest cavitation inclination is illustrated in FIG.
  • the pressure profile at a corresponding buoyancy profile 3 which is here formed for example as NACA 0015 profile shown.
  • FIG. 5 shows a wave energy converter which can make use of the wave orbital movement shown in FIG.
  • the wave energy converter is designated overall by 1. It has a rotor 2, 3, 4 with a rotor base 2, on which over rotor or lever arms 4 elongated lift profiles 3 are mounted.
  • a single-sided rotor is shown, but the method can also be performed in two-sided rotors.
  • the lift profiles 3 are connected at one end to the lever arms 4 and, for example, via adjusting devices 5 at an angle (so-called pitch angle) about its longitudinal axis rotatable.
  • the adjusting devices 5 may alternatively or additionally also be designed to displace the buoyancy profiles 3 in each case in an adjustment region 8, whereby a circumferential radius of the buoyancy profiles 3 about the center of the rotor 2, 3, 4 or a corresponding rotation axis can be changed or Shape or geometry of the lift profiles 3 to change.
  • the adjusting devices 5 may be associated with corresponding encoders 6, which are designed, for example, as a means for detecting a speed of the water body flowing into the lift profiles 3 and / or as a means for detecting a total pressure.
  • the encoders 6 can be assigned individually to each lift profile 3 in order to enable the most exact possible detection of the locally prevailing conditions. Alternatively, however, corresponding donors 6 may also be provided in common for a plurality of lift profiles 3, which allows a more cost-effective creation and easier evaluation.
  • the encoders 6 can also be arranged at a location other than that shown, for example at a center of a wave energy converter park.
  • the encoders 6 can also comprise position encoders which can output a respective set angle of attack of the relevant lift profile 3 to a control device.
  • the buoyancy profiles 3 are, relative to the axis of the rotor 2, 3, 4, offset from one another at an angle of 180 °.
  • the buoyancy profiles 3 are preferably connected to the lever arms 4 in the vicinity of their pressure point, in order to reduce rotational torques occurring during operation to the buoyancy profiles 3 and thus to reduce the requirements for the holder and / or the adjusting devices.
  • the radial distance between a suspension point of a buoyancy profile 3 and the rotor axis is, for example, 1 m to 50 m, preferably 2 m to 40 m and particularly preferably 6 m to 30 m. He is, as mentioned, adjustable in a control range 8.
  • the chord length of the lift profiles 3 is, for example, 1 m to 8 m, the largest longitudinal extent, for example, 6 m or more.
  • the wave energy converter 1 has an integrated generator.
  • the rotor base 2 is rotatably mounted in a generator housing 7.
  • the rotor base 2 forms the rotor of the generator, the generator housing 7 whose stator.
  • the required electrical equipment, such as coils and cables are not shown. In this way, a rotational movement of the rotor base 2 induced by the wave orbital motion can be directly converted into electrical energy with the lift profiles 3 attached thereto via the lever arms 4.
  • a wave energy converter 1 is shown in FIG. 5, in which the lift profiles 3 are attached via their lever arms 4 to only one side of a rotor base 2, the invention can also be used with wave energy converters 1, on both sides of the rotor base 2 lever arms 4 and 3 Auftriebsprofile are attached.
  • the rotor arms 4 need not necessarily be formed as shown.
  • the lift profiles 3 can also be connected to the rotor base 2 via a disk-shaped element.
  • the buoyancy profiles 3 are also only examples of movable elements on which cavitation can occur.
  • the invention can also be used with other types of wave energy converters 1.
  • the wave energy converter 1 of Figure 5 is again shown in plan view of the rotor base 2 and more schematically.
  • the wave energy converter 1 has a generator housing 7 with an electric generator and a rotor 2, 3, 4 rotatably mounted thereon with a rotor base 2 and two coupling bodies in the form of hydrodynamic lift profiles 3 attached to the rotor base 2 in each case via rotor arms 4.
  • the buoyancy profiles 3 protrude in the figure 6 from back to front in the body of water.
  • a control unit is shown schematically and designated 200.
  • the rotor 2, 3, 4 is below the water surface of a wavy moving body of water, such as an ocean, arranged.
  • An axis of rotation of the rotor (perpendicular to the plane of the drawing) is oriented largely horizontally.
  • a pitch or pitch angle ⁇ of the two buoyancy profiles 3 with respect to each perpendicular up or down tangent to the rotor can be adjusted.
  • the angle of attack ⁇ of the two lift profiles are preferably oriented counter to one another and have, for example, values of -20 ° to + 20 °. In particular, when starting the wave energy converter 1 or low Kavitationsne Trent but larger angles of attack can be provided.
  • the angles of attack can be set in particular as a function of the cavitation on the size influencing the buoyancy profiles 3. For example, an adjustment amount can be limited depending on a corresponding size. Preferably, the angle of attack ⁇ can be adjusted independently.
  • the displacement devices 5 may be electromotive adjusting devices, preferably with stepper motors, hydraulic and / or pneumatic components.
  • encoders 6 can be assigned to the two adjusting devices 5.
  • Another sensor not shown, can determine the angle of rotation of the rotor base 2 relative to the housing 7, on the basis of which a phase offset of the rotor 2, 3, 4 to the exciting wave field can be determined as the parameter value.
  • the invention is also suitable for systems without adjustment devices 5 for adjusting the pitch or pitch angle ⁇ and / or corresponding sensors.
  • the lifting profiles 3 can be displaced in an adjustment region 8 (shown only with respect to the right-hand uplift profile 3), whereby a circumferential radius of the lift profiles 3 around the Center of the rotor 2, 3, 4 or a corresponding axis of rotation can be changed.
  • the wave energy converter 1 is flown by the orbital flow at a speed ⁇ .
  • This is the orbital flow of sea waves (see FIG. 1) whose direction changes continuously with an angular velocity ⁇ .
  • f represents the frequency of the monochromatic wave.
  • FIG. 6 thus shows a snapshot.
  • the rotation of the orbital flow is oriented in the counterclockwise direction, ie the associated wave propagates from right to left.
  • a buoyancy indicated by the force vector F
  • a first torque acting on the rotor 2, 3, 4 are generated.
  • a preferably variable second torque in the form of a resistance that is to say a braking torque, or an acceleration torque can be applied to the rotor 2, 3, 4.
  • Means for generating the second torque may be realized by the generator.
  • phase angle or offset ⁇ the amount of which can be influenced as a parameter value by a suitable adjustment of the first and / or second torque.
  • the illustration of the lift profiles 3 in FIGS. 5 and 6 takes place only as an example for the definition of the different operating parameters.
  • the angle of attack of the two buoyancy profiles 3 can also be designed opposite to the representation. The left buoyancy profile 3 in FIG. 6 would then be adjusted inwards and the right buoyancy profile 3 in FIG.
  • FIG. 7 illustrates a method according to an embodiment of the invention in the form of a schematic flow chart, which is denoted overall by 100.
  • the method illustrated at 100 is implemented, for example, in a drive unit 200 of a wave energy converter 1 as previously shown.
  • the method begins in a step 101 with detection or determination of a variable which influences a cavitation on at least one movable element, for example a buoyancy profile 3 of the wave energy converter 1.
  • this may be, for example, a velocity of a water body, a flow velocity between buoyancy profile 3 and water body, a hydrostatic pressure of the water body, which bears on the corresponding buoyancy profile, and / or a total pressure. Corresponding sizes are designated 1 0.
  • the determination of a cavitation tendency, in particular the minimum total pressure at the surface or in the immediate vicinity of the buoyancy profile takes place.
  • the shape of the lift profile is known in the system, angle of attack and flow velocity are easily determined from known or measured variables. From this, the location and value of the minimum total pressure can be calculated.
  • the direct determination of the total pressure by means of pressure sensors is possible by mounting them at the neuralgic points.
  • the suction tip on a corresponding buoyancy profile are determined.
  • a vapor pressure as the lower threshold value, which is preferably taken as a function of the temperature and the height of the water column over the profile or over the system, for example, a memory device of a wave energy converter controlling arithmetic unit.
  • the undershooting of the vapor pressure is prevented by outputting a corresponding manipulated variable in a step 103, which causes the position and / or position of the at least one movable element to be set in a wave energy converter. This is illustrated by 120.
  • the position can be changed, for example, in the form of a change of a radius of rotation and / or the position in the form of a change in a setting angle.
  • Another possibility is to change the geometry by changing the position of certain components, such as parking flaps and the like.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)

Abstract

L'invention concerne un procédé pour l'utilisation d'un convertisseur d'énergie houlomotrice (1) dans une nappe d'eau, dans lequel, pour éviter la cavitation, sur au moins un élément mobile (3) du convertisseur d'énergie houlomotrice (1), on détermine au moins une grandeur qui influe sur la cavitation affectant le ou les éléments mobiles (3), à partir de la ou des grandeurs qui influent sur la cavitation sur le ou les éléments mobiles (3), en particulier une pression totale minimale agissant sur au moins un endroit (32) de l'élément mobile (3), on compare la pression totale observée à une valeur seuil inférieure et on ajuste une position, disposition et/ou géométrie du ou des éléments mobiles sur la base de la comparaison.
PCT/EP2013/003638 2012-12-17 2013-12-03 Procédé et moyen pour la réduction de la cavitation dans des convertisseurs d'énergie houlomotrice WO2014094979A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102012024592.0 2012-12-17
DE102012024592 2012-12-17
DE102013005040.5 2013-03-25
DE102013005040.5A DE102013005040A1 (de) 2012-12-17 2013-03-25 Verfahren und Mittel zur Kavitationsreduktion bei Wellenenergiekonvertern

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WO2014094979A1 true WO2014094979A1 (fr) 2014-06-26

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Cited By (4)

* Cited by examiner, † Cited by third party
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CN110578640A (zh) * 2019-10-29 2019-12-17 安徽工业大学 一种双叶轮水轮机
CN113653586A (zh) * 2021-10-20 2021-11-16 自然资源部第一海洋研究所 一种基于普林斯顿海洋模式的水动力系统
CN115081138A (zh) * 2022-06-22 2022-09-20 武汉大学 改善水泵水轮机运行稳定性的导叶设计方法和水泵水轮机
CN115081138B (zh) * 2022-06-22 2024-05-31 武汉大学 改善水泵水轮机运行稳定性的导叶设计方法和水泵水轮机

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