DK164294B

DK164294B - Method and member for changing the shape of the tip of an existing windmill sail

Info

Publication number: DK164294B
Application number: DK114190A
Authority: DK
Inventors: Henrik Stiesdal
Original assignee: Danregn Vindkraft As
Priority date: 1990-05-08
Filing date: 1990-05-08
Publication date: 1992-06-01
Also published as: DK164294C; DK114190A; DK114190D0

Description

iin

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5 Den foreliggende opfindelse angår en fremgangsmåde til ændring af tippens form på en eksisterende vindmøllevinge. Endvidere angår opfindelsen et organ til brug ved udøvelse af den anførte fremgangsmåde samt anvendelse af organet.The present invention relates to a method of changing the shape of the tip on an existing wind turbine blade. Furthermore, the invention relates to a means for use in the practice of the aforementioned method and to use the means.

10 I forbindelse med etablering af vindmøller udføres der et intensivt forskningarbejde med henblik på opnåelse af den béds-t mulige virkningsgrad for den enkelte vindmølletype samt reduktion af vindmøllens støjemission.10 In connection with the establishment of wind turbines, intensive research is carried out with a view to obtaining the best possible efficiency for the individual wind turbine type and reducing the noise emission of the wind turbine.

15 Det hører til almen viden for en fagmand på området, at især vingetippen har betydelig indflydelse på ydelse og støjemission for en vindmøllevinge. Vingetippens udformning har ligget fast for det enkelte produkt, så det har været en fast parameter ved en given vinge, hvordan vingetippen 20 var udformet.15 It is common knowledge for one of ordinary skill in the art that the blade tip in particular has a significant impact on the performance and noise emission of a wind turbine blade. The design of the blade tip has been fixed for the individual product, so that the blade tip 20 was designed as a fixed parameter for a given blade.

I takt med den udførte forskning har det imidlertid ofte vist sig, at man ved forholdsvis små ændringer af en vindmøllevinge og især af dens vingetip kunne opnå væsentlig 25 forbedring af såvel virkningsgrad som støjemission, men sådanne ændringer har tidligere kun været udført ved en total udskiftning af vingerne på vindmøllen, hvilket selvsagt er kostbart, idet dette medfører en skrotning af de i og for sig fortsat brugbare vindmøllevinger. Således har en ameri- 30 kansk fabrikant forsøgt sig med en alternativ vingetip på en ældre vingekonstruktion, men denne nye vingetip er bibragt vingen ved en ændring af den oprindelige støbeform, hvori vingen blev fremstillet.However, in conjunction with the research carried out, it has often been found that with relatively small changes of a wind turbine blade and in particular of its blade tip, substantial improvement in both efficiency and noise emission could be achieved, but such changes have previously only been made by a complete replacement. of the blades on the wind turbine, which is of course expensive, since this results in scrapping of the wind turbine blades that are still usable in themselves. Thus, an American manufacturer has tried an alternate blade tip on an older blade assembly, but this new blade tip is provided with the blade by a change in the original mold in which the blade was manufactured.

35 Der består derfor et behov for at kunne forbedre virknings graden af en bestående vindmølle, uden at det er nødven-35 There is therefore a need to be able to improve the efficiency of an existing wind turbine without the need for

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2 digt at kassere de i og for sig fuldt anvendelige vindmøllevinger, som blot ikke længere er i stand til at leve op til de nyeste forskningsresultater på området.2 poems to discard the fully usable wind turbine blades, which are simply no longer able to live up to the latest research results in the field.

5 Det er således formålet med den foreliggende opfindelse at angive en fremgangsmåde til ændring af tippens form på en eksisterende vindmøllevinge, så det ikke vil være nødvendigt at kassere denne, idet der samtidigt skal angives et organ til brug ved udøvelse af den omhandlede fremgangsmåde 10 samt anvendelse af dette organ.Accordingly, it is an object of the present invention to provide a method for changing the shape of the tip on an existing wind turbine blade so that it will not be necessary to discard it, as a means for use in the practice of the present method 10 and use of this body.

Détte formål opnås ved en fremgangsmåde, der ifølge opfindelsen er særegen ved, at i det mindste den radialt yderste ende af vingen forsynes med en hætte, hvis ydre overflade 15 er forskellig fra den ydre form af vingebladet og vingetip-pen, idet den enten har, eller under vingens drift indtager, den ønskede ændrede form, henholdsvis ved et organ til brug ved udøvelse af den angivne fremgangsmåde, hvilket organ ifølge opfindelsen er særegent ved, at organet har form 20 som en hætte, der er indrettet til at kunne anbringes på i det mindste den radialt yderste ende af vingen, og at hættens ydre overflade er forskellig fra den ydre form af den radialt yderste ende af vingebladet og vingetippen.This object is achieved by a method which according to the invention is peculiar in that at least the radially outermost end of the blade is provided with a cap whose outer surface 15 is different from the outer shape of the blade and the blade tip, having either , or during the operation of the wing, takes the desired altered form, respectively, by a means for use in the practice of the indicated method, which means according to the invention is peculiar in that the means is of form 20 as a cap adapted to be mounted on at least the radially outermost end of the wing, and that the outer surface of the cap is different from the outermost shape of the radially outermost end of the blade and wing tip.

25 Ved denne i og for sig beskedne konstruktion er det muligt ved eftermontage på en eksisterende vindmølles vinger at ændre vingernes facon til en ydre form, der kan leve op til de nyeste forskningsresultater inden for vindmølleteknikken og uden at skulle kassere de bestående vindmøllevinger.25 In this modest construction, it is possible to retrofit the wings of an existing wind turbine to an external shape, which can live up to the latest research results in the wind turbine technology and without having to discard the existing wind turbine blades.

30 Herved er det blevet muligt med beskedne omkostninger og med simple midler at opnå en aerodynamisk forbedring, der kan udmønte sig i forøget produktion, reduceret støjemission, bedre funktion af luftbremser og lignende foranstaltninger, hvorved værdien af disse forbedringer langt over-35 stiger prisen på udøvelse af fremgangsmåden.30 It has thus been possible, with modest costs and with simple means, to achieve an aerodynamic improvement which can result in increased production, reduced noise emission, better functioning of air brakes and similar measures, thereby increasing the value of these improvements over the price of practicing the procedure.

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Fremgangsmåden og organet ifølge opfindelsen er fordelagtig ved, at hætten kan udføres som en tynd skal, for eksempel af glasfiber, metal eller et lignende materiale, hvorved man dels kan tilpasse hættens ydre form på den mest fordel-5 agtige måde og dels kan gøre dette ved den lavest mulige forøgelse af vægten af den således ændrede vinge.The method and means according to the invention are advantageous in that the cap can be made as a thin shell, for example of fiberglass, metal or a similar material, whereby one can adjust the outer shape of the cap in the most advantageous way and partly do so at the lowest possible increase in the weight of the wing thus changed.

Det er også fordelagtigt, at hætten på den i brugsstillingen radialt yderste ende udføres med en dråbe- eller torpe-10 doformet del, der er tildannet af for eksempel polyure-thanskum, gummi eller et lignende materiale, idet længderetningen af den dråbe- eller torpedoformede del hovedsageligt strækker sig tangentielt i forhold til vingebladets længderetning, og at overgangen mellem den tynde skal og 15 den dråbe- eller torpedoformede del udføres elastisk efter-givelig på en sådan måde, at længderetningen af delen kan ændre hældning i forhold til den tynde skal og denned også til vingebladets rotationsplan.It is also advantageous that the cap at the radially outermost end be used with a drop or torpedo shaped part formed of, for example, polyurethane foam, rubber or a similar material, the longitudinal direction of the drop or torpedo shaped portion extends tangentially with respect to the longitudinal direction of the blade, and the transition between the thin shell and the droplet or torpedo-shaped portion is elastically compliant in such a way that the longitudinal direction of the portion can change inclination relative to the thin shell and this also to the blade's rotation plane.

20 Herved er det muligt for den dråbe-, eller torpedoformede del at ændre længderetning, så denne passer bedst muligt efter retningen af den i afhængighed af vingebladets rotationstal foreliggende slipstrøm ved vingetippen, hvorved støjemissionen mindskes ved, at trykforskellen mellem vind-25 og læside af vingen reduceres.Hereby it is possible for the droplet or torpedo-shaped part to change the longitudinal direction so that it fits as best as possible in the direction of the slip current at the blade tip, depending on the rotation speed of the blade, thereby reducing the noise emission by reducing the pressure difference between wind 25 and reading side of the the wing is reduced.

Fremgangsmåden og organet ifølge opfindelsen skal forklares nærmere i det følgende under henvisning til tegningen, hvor: 30 fig. la, b og c viser en eksisterende vindmøllevinge, som er modificeret ifølge opfindelsen ved anbringelse af en hætte på den radialt yderste ende af vingen, set vinkelret på vingens rotationsplan, tangenti-35 alt i dette plan og vinkelret på vingens længdeak se henholdsvis radialt udefra indefter i nævnteThe method and means according to the invention will be explained in more detail below with reference to the drawing, in which: FIG. 1a, b and c show an existing wind turbine blade modified according to the invention by placing a cap on the radially outermost end of the blade, viewed perpendicular to the rotational plane of the blade, tangential to this plane and perpendicular to the longitudinal axis of the blade, respectively radially from the outside within the said

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4 plan, fig. 2 viser den yderste ende af den i fig. 1 afbildede vindmøllevinge og det herpå anbragte organ, 5 fig. 3a, b og c viser en eksisterende vindmøllevinge, som er modificeret ifølge opfindelsen, idet det på vingen anbragte organ er forsynet med en dråbeeller torpedoformet del på den radialt yderste en-10 de af vingebladet, set på samme måde, som i fig.4, FIG. 2 shows the outer end of the one shown in FIG. 1 depicts the wind turbine blade and the means placed thereon; FIG. 3a, b and c show an existing wind turbine blade modified in accordance with the invention, with the member disposed on the blade having a dropper or torpedo-shaped part on the radially outermost end of the blade, seen in the same way as in fig.

1/ og fig. 4 er et til fig. 2 svarende billede af det i fig. 3 afbildede vingeblad.1 and FIG. 4 is a view of FIG. 2 is a view similar to that of FIG. 3 pictured wing leaves.

15 I fig. 1 er med 1 angivet et eksisterende vindmølleblad 1, hvis i vindmøllebladets 1 brugsstilling radialt yderste ende 2 er skraveret til angivelse af den del af vindmøllebladet, der fortrinsvis kan forsynes med et organ 3 til forbe-20 dring af vindmøllebladets 1 aerodynamiske form, så denne nye form kan tilfredsstille de nyeste fremskridt inden for forskningen af vindmøller.In FIG. 1 is an existing wind turbine blade 1, whose radially outer end 2 of the wind turbine blade 1 is shaded to indicate the portion of the wind turbine blade which can preferably be provided with a means 3 for improving the aerodynamic shape of the wind turbine blade 1 new form can satisfy the latest advances in wind turbine research.

Organet 3, der er vist i fig. 2, foreligger som en hætte, 25 hvis indvendige overflade er tilpasset vindmøllebladets 1 overflade til tætsluttende anlæg, og hvis ydre overflade adskiller sig fra den ydre form af vindmøllebladet 1 på en sådan måde, at dettes aerodynamiske egenskaber forbedres, så der kan opnås en forøgelse af vindmøllebladets virk-30 ningsgrad og en reduktion af støjemissionen fra vindmøllebladet 1 under dettes drift og især fra vingetippen.The member 3 shown in FIG. 2, is provided as a cap whose inner surface is adapted to the surface of the wind turbine blade 1 for sealing systems and whose outer surface differs from the outer shape of the wind turbine blade 1 in such a way that its aerodynamic properties are improved so that an increase can be achieved. of the efficiency of the wind turbine blade and a reduction of the noise emission from the wind turbine blade 1 during its operation and in particular from the blade tip.

Denne hætte 3 er udført som en tynd skal af for eksempel glasfiber, metal eller et lignende materiale, der nemt kan 35 tildannes i den ønskede facon.This cap 3 is designed as a thin shell of, for example, fiberglass, metal or a similar material that can easily be formed in the desired shape.

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Hætten 3 er forsynet med på tegningen ikke viste fastgørelsesorganer, der kan tjene til på sikker måde at holde hætten 3 på plads på vindmøllebladet 1, så hætten 3 ikke slynges bort under indvirkningen af centrifugalkræfterne under 5 vindmøllens drift.The cap 3 is provided with fasteners not shown in the drawing which can serve to securely hold the cap 3 in place on the wind turbine blade 1 so that the cap 3 is not thrown away under the action of centrifugal forces during the operation of the wind turbine.

Hættens 3 form kan beskrives således: Med hætten 3 monteret på vindmøllebladet 1 forlænges dette med for eksempel 500 mm. Den eksisterende vingetips 2 forkant 4 forlænges radi-10 alt udefter stort set i efter en ret linie. Bagkanten 5 krummes efter en cirkelbue frem mod den forlængede forkant 4,i så for- og bagkant 4, 5 mødes i en spids 6, der dog afrundes passende over for eksempel 10 - 20 mm. Vingens 1 vindside 7 (den flade side) fastholdes udefter, så redukti-15 onen i tykkelse foretages fra den modstående krumme side 8 af vingebladet 1.The shape of the cap 3 can be described as follows: With the cap 3 mounted on the wind turbine blade 1 this is extended by, for example, 500 mm. The existing blade tip 2 leading edge 4 extends radius-10 all along substantially in a straight line. The trailing edge 5 is curved, following a circular arc, towards the extended leading edge 4, in which the leading and trailing edge 4, 5 meet at a point 6, which is however rounded appropriately over, for example, 10 - 20 mm. The wind face 7 of the blade 1 (the flat side) is held outwardly so that the reduction in thickness is made from the opposite curved side 8 of the blade 1.

Et tværsnit af hætten 3 nær spidsen 6 må gerne have det oprindelige profil af vingebladet 1, men dette er dog ikke 20 strengt nødvendigt, da hættens 3 funktion mere er at forme en randhvirvel end at skabe egen opdrift.A cross-section of the cap 3 near the tip 6 may have the original profile of the blade 1, but this is not strictly necessary, since the function of the cap 3 is more to form a vertebra than to create its own buoyancy.

Hættens 3 tykkelse kan beregningsmæssigt holdes på noget under 2 mm godstykkelse under forudsætning af et passende 25 egnet materiale, hvorfor en endelig godstykkelse på 2 - 3 mm vil være passende. Det er klart, at det vil være lettere at tildanne en hætte 3 efter et foreliggende vindmølleblad 1 jo mindre godstykkelsen er.The thickness of the cap 3 can be calculated computationally to anything less than 2 mm thickness, provided a suitable suitable material, therefore a final thickness of 2-3 mm will be appropriate. Obviously, it will be easier to form a cap 3 after a present wind turbine blade 1 the smaller the thickness.

30 Hætten 3 kan fæstnes til vindmøllebladet 1 på enhver måde, som måtte være velegnet ud fra det materiale, hvoraf vindmøllebladet 1 og hætten 3 selv er blevet fremstillet. Der kan for eksempel hertil anvendes skruer eller hætten kan fastgøres ved klæbning eller svejsning.The cap 3 can be attached to the wind turbine blade 1 in any manner that may be suitable from the material from which the wind turbine blade 1 and the cap 3 have themselves been manufactured. For example, screws may be used for this, or the cap may be secured by adhesive or welding.

Hætten 3 kan have en fast given form, eller den kan have en 35The cap 3 may have a fixed shape or it may have a 35

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6 vis fleksibilitet, opnået ved elasticitet i materialet, ved hjælp af hængsler eller lignende foranstaltninger, så hætten 3 i større eller mindre grad kan indrette sig efter en relativ vind ved vingetippen 2, og derved i endnu højere 5 grad kan mindske støjemission ved at reducere trykforskellen mellem vind- og læside af vindmøllebladet 1.6 shows some flexibility, obtained by elasticity of the material, by hinges or similar measures, so that the cap 3 can more or less align with a relative wind at the wing tip 2, thereby reducing even more noise 5 by reducing noise emission the pressure difference between wind and reading side of the wind turbine blade 1.

På fig. 3 og 4 er hætten 3 ifølge opfindelsen vist med en særligt fordelagtig udførelsesform, idet den i brugsstil-10 lingen radialt yderste ende af hætten 3 er -udstyret med en dråbe- eller torpedoformet del 9. Den dråbe- eller torpedo-formede dels 9 længderetning forløber i det væsentlige i vindmøllevingens 1 rotationsplan og tangentielt i forhold til dette.In FIG. 3 and 4, the cap 3 of the invention is shown in a particularly advantageous embodiment, in the radially outermost end of the cap 3 being provided with a drop or torpedo-shaped part 9. The longitudinal direction of the drop or torpedo-shaped part 9 extends substantially in the plane of rotation of the wind turbine blade 1 and tangentially with respect thereto.

1515

Den dråbe- eller torpedoformede del 9 kan fremstilles som et hult legeme eller kan være massivt, idet der efter omstændighedern vælges, et hertil egnet .materiale, der for eksempel . kan være polyurethanskum, gummi eller et lignende 20 materiale.The droplet or torpedo-shaped part 9 may be made as a hollow body or may be solid, as appropriate, selecting a material suitable for this purpose, for example. may be polyurethane foam, rubber or similar material.

Den dråbe- eller torpedoformede del 9 kan fremstilles ved formstøbning eller tilsvarende for en fagmand almindeligt kendte produktionsmetoder.The droplet or torpedo-shaped part 9 can be made by molding or similar to those of ordinary skill in the art.

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Funktionen af den dråbe- eller torpedoformede del 9 hænger sammen med en forbedret afløsning af randhvirvlen på vindmøllebladet 1, og der er ved forsøg konstateret såvel en betydelig produktionsforbedring som en væsentlig reduktion 30 af vingens 1 støjemission.The function of the drop or torpedo-shaped part 9 is related to an improved release of the eddy on the wind turbine blade 1, and a significant improvement in production as well as a significant reduction in the noise emission of the blade 1 has been found in experiments.

Ved en eksisterende vindmøllepark, som omfatter tre ens vindmøller, blev vindrotoren på en af møllerne forsynet med hætter 3 med en dråbe- eller torpedoformet del 9. I lø-35 bet af en forsøgsperiode, som omfattede 110 døgn inden ændringen ved påsætning af hætterne og 90 døgn efter ændrin-At an existing wind farm, which includes three identical wind turbines, the wind rotor on one of the turbines was fitted with caps 3 with a drop or torpedo-shaped part 9. During an experimental period which included 110 days before the change in the hoods and 90 days after change

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7 gen, blev der konstateret en væsentlig forbedring for den modificerede mølle.7 gene, a significant improvement was found for the modified mill.

Før ændringen producerede denne ene mølle således kun ca.Before the change, this one mill thus produced only approx.

5 75% af gennemsnittet af de to andre møller, medens den ef ter montagen af hætter 3 med dråbe- eller torpedoformede dele 9 producerede omkring 105% af gennemsnittet af de andre møller.5 represents 75% of the average of the other two turbines, whereas after mounting caps 3 with drop or torpedo-shaped parts 9 produced about 105% of the average of the other turbines.

10 De produktions forbedringer, der kan opnås, synes at være i størrelsesordenen 10 - 20% på årsproduktionen, svarende til for eksempel til en årlig merindtjening på 10.000 - 20.000 kr. for en 150 kW vindmølle. Montage af hætter 3 forsynet med dråbe- eller torpedoformede dele 9 anslås at kunne ud-15 føres for 5.000 - 10.000 kr. pr. 150 kW vindmølle.10 The production improvements that can be achieved appear to be in the order of 10 - 20% on annual production, corresponding to, for example, an annual additional income of DKK 10,000 - 20,000 for a 150 kW wind turbine. Mounting of caps 3 provided with drop- or torpedo-shaped parts 9 is estimated to be feasible for DKK 5,000 - 10,000 per head. 150 kW wind turbine.

Claims

Method for changing the shape of the tip on an existing wind turbine blade, characterized in that at least the radially outermost end of the blade (1) is provided with a cap (3) whose outer surface is different from the outer shape of the radially the outer end (2) of the blade (1) and the blade tip, having either, or during the operation of the blade, the desired changed shape. 10

Process according to claim 1, characterized in that the cap (3) is made as a thin shell, for example of fiberglass, metal or a similar material.

Method according to claim 2, characterized in that the cap (3) is formed on the outermost radially outer end with a drop or torpedo-shaped part (9) formed, for example, of polyurethane foam, rubber or a similar material, the longitudinal direction. the droplet or torpedo-shaped portion (9) extends substantially tangentially with respect to the longitudinal direction of the blade (1), and the transition between the thin shell and the droplet-shaped or torpedo-shaped portion (9) is resiliently resilient in such a manner. that the longitudinal direction of the part (9) can change inclination with respect to the thin shell and thus also to the plane of rotation of the blade (1).

Method according to any one of the preceding claims, characterized in that the cap (3) is fixed to the radially outermost end (2) of the blade (1) by means of fasteners such as screws, welding, adhesive or similar means.

A device for use in the practice of the method of claim 1 for changing the shape of the tip to an existing one. wind turbine blade, characterized in that the member DK 164294 B 9 is in the form of a cap (3) adapted to be mounted on at least the radially outermost end (2) of the wing (1) and the cap (3) outer surface is different from the outer shape of the radially outer end (2) of the blade (1) and the wing tip.

6. A device according to claim 5, characterized in that the cap (3) is a thin shell consisting, for example, of fiberglass, metal or a similar material.

A device according to claim 6, characterized in that the cap (3) has on the radially outermost end in the position of use a drop or torpedo-shaped part (9) consisting, for example, of polyurethane foam, rubber or a similar material. the longitudinal direction of the drop or torpedo-shaped portion (9) extending substantially tangentially with respect to the longitudinal direction of the blade (1), and the transition between the thin shell and the drop or torpedo-shaped portion (9) being resiliently resilient in such a manner that the longitudinal direction of the part (9) can change inclination with respect to the shell and thus also to the plane of rotation of the blade (1).

A device according to any one of claims 5-7, characterized in that the shell has fasteners which are arranged to be able to hold the cap to the radially outermost end (2) of the blade (1), which means are, for example, screws. , welding, adhesive or similar means.

Use of the device according to claims 5 to 8 for application to an existing wind turbine blade (1) to improve its efficiency and reduce its noise emission.