Bibliotheek TU Delft C

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1 Bibliotheek TU Delft C

3 THE ANGLES OF THE KOLIBRIE ROTOR TIPVANES ON THE ROns AND ON THE BLADES A. Bruining Delft University Press, 1988

4 Published nd distributed by: Delft University Press Stevinweg cN Delft The Netherlnds By order of: Delft University of Technology Institute for Windenergy Kluyverweg HS Delft The Netherlnds Report IW-R515 October 1988 Crried out within the Dutch Development Progrm for Wind Energy (NOW-2); by order of the Mngement Office for Energy Reserch PEO; finnced by the Ministry of Economic Affirs. CIP-GEGEVENS KONINKLIJKE BIBLIOTHEEK, DEN HAAG Bruining, A. The ngles of the kolibrie rotor tipvnes on the rods nd on the bldes / A. Bruining. - Delft : Delft University Press , fig., tb. Crried out within the Dutch Development Progrm for Wind Energy (NOW-2); by order of the the Mngement Office for Energy Reserch PEO. - Report IW-R Met lito opg. ISBN SISO UDC 533: NUGI 834 trefw.: windmolens; erodynmic.. copyrightby Delft University Press. No prt of this book my be reproduced in ny form by print, photoprint, microfilm or ny other mens, without written permission from Delft University Press.

5 - 2 - Content$ pg. Smy 3 1. Symbols 4 2. Introduction 6 3. Tests nd methods Mesuring methods Definition of the ngles in the first mesuring method Second mesuring method Accurcy Results References 12 Tbles 13 Figures 17

6 - 3 - Summry This report contins the dt of the djusted ngles of the tipvnes used on the Kolibrie rotor bldes nd rods. Two mesuring methods for the determintion of these ngles were pplied: one method is bsed on determining the chord vector nd the spn wise vector of the tipvne. The other method is bsed on the ngles of the mounting prts of the tipvnes. The theoreticl bckground of the different ngles systems, used to de fine the ttitude of the tipvne in the 3-dimensionl spce nd the mesurement procedure re not included in this report, but is explined in ref. 1. Due to the unrelibility of the position of the chord vector nd the spn wise vector the results from this first method were not used for further clcultions. All further clcultions were crried out with the dt from the second method, bsed on the ngles of the mounting prts of the tipvnes.

7 Symbols offset distnce of the tipvne, see fig. 1 (m) b distnce between center line of the mounting prt nd 25% chord point of the Kolibrie tipvne, see fig. 1 (m) c chord of the tipvne (m) R rotor tip rdius (m) vb h or mesurement ngle of the tipvne, defined in section 3.1 vb vert mesurement ngle of the tipvne, defined in section 3.1 mesurement ngle of the tipvne, defined in section 3.1 mesurement ngle of the tipvne, defined in section 3.1 flpping ngle y tilt ngle of the tipvne (dègrees) A.VC h or difference in the tipvne mesurement ngle vc,denotes ccurcy, h or see section 7.3 of ref. 1 e:: rotor blde twist ngle bsed on the blde length

8 - 5-8 incidence ngle of the tipvne 8' mounting prt ngle, defined in fig. 1 built-in mounting prt ngle, defined in fig. 1 8 ref blde pitch ngle mesured t the reference surfce on the connection of the hub element nd the rotor blde blde tip pitch ngle, ngle between tip chord nd rotor disc plin sweep ngle of the tipvne A g (= A * cos r ) mesured sweep ngle of the tipvne (= ir * 180/n) tipvne offset ngle, see fig. 1 indices indictes erodynmic tipvne ngles k indictes Kolibrie tipvne ngles indictes flpping ngles

9 Introduction For mounting the tipvnes of the Kolibrie rotor on the rotor bldes or rods there exist 3 mounting prts. The ngles of the mounting prts cnnot be djusted. The only chnge of geometry is possible by vrying the blde root pitch which gives sweep ngle vrition. Mounting prt 1 is the oldest one. It gives moderte lift on the tipvnes. It is lso clled the brek even mounting prt, becuse the Kolibrie rotor produced with this set the sme nett power output s without tipvnes. Mounting prt 2 gives the tipvne very high lift. It ws designed to crete strong mss flow increse. Due to the high drg the nett power output ws low. This set is clled the seprtion mounting prt. Mounting prt 3 hs lift coefficient between mounting prt 1 nd 2 to void the high drg nd flow seprtion. The sme mounting prts cn be used for connecting the tipvne on the rotor blde or rod. The mounting prts hve some principl built-in ngles. See tble 1. With the mesuring method of section 7 of ref. 1 it is not necessry to know wht these built-in ngles re, becuse the erodynmic ngles of the tipvne re directly clculted from the mesurement ngles. See for n explntion of the vrious type of ngles ref. 1. The sequence of the 3 Euler ngles which should be used is: 1. set the incidence ngle Bk 2. set the sweep ngle '\ 3. set the til t ngle r k

10 \ This is the prescribed sequence of the construction ngles, but there ws difference in the ctul construction of the mounting prts. The xis on which the tilt ngle is introduced is here the non-swept chord vector (index c). For the construction ngles the tilt ngle is introduced round the swept chord vector (see section of ref. 1).

11 Tests nd methods 3.1 Mesuring methods Two mesuring methods were used to determine the tipvne ngles of the Kolibrie rotor. The ngles of the Kolibrie tipvnes re mesured nd clculted by the method described in section 7 of ref. lnd by method bsed on the mesurements of the geometry of the mounting prts. For the mesuring method of section 7 of ref. 1 wood en mould ws used for determining the chord line. One edge of the mould is exctly prllel with the chord vector. The verticl vector ws creted with plumb line. The tipvne offset ngle is directly determined from the geometry by using the distnce (see fig. 1). = * R 180 The rdius R of the rotor is m. Since is known, the expression with vc t (see section 7.3 of ref. 1) is used for ver checking Definition of the ngles in the first mesuring method 1 The line from the 2 chord point of the tipvne t the mounting prt towrds the rotor shft is positioned exctly horizontl. The ngle between the verticl vector v nd the spn vector b is then clled vb. The ngle between v nd the chord vector c is vc. The sme h or 1 h or ngles re mesured once gin with the line from the 2 chord point of tipvne t the mounting prt now positioned exctly verticl. These ngles re denoted vb vert nd vc vert respectively. See fig. 3 vb hor ' vb vert ' vc hor nd vc vert re clled the mesurement ngles.

12 The second mesuring method The second mesuring method us es the built-in ngles. Ak nd Y k re built-in in the tipvne itself. 8 km is built-in in the mounting prt. The tipvne fits in such wy in the mounting prt tht 8 = 0 km if the outside surfce of the mounting prt is prllel with the locl tngent. 8 cn be 'clculted by: km 8 = 8' - * 180 = 8' - km R TI 8' is the ngle between the outside surfce of the mounting prt nd the tngent of the power blde or rod (see fig. 1). The vlues of the offset distnce nd 8' re given in tble 1. But the xis of A of the erodynmic ngles coincides with the xis of St ' of the blde pitch ngle. So the correction of different p blde tip pitch ngle on the erodynmic ngie is mde by : AA This reltion ws used for correcting the sweep ngle A of the tipvne, tht ws connected on the rotor blde for the different blde tip ngle settings. 8. ws determined from 8 f nd the t l.p re blde twist E: (bsed on the blde length) by: + E: The blde twist E: depends on the rottion speed of the rotor. This is cused by the limited torsionl stiffness of the Kolibrie rotor bldes nd the lrge torsionl moment generted by the tipvne. This blde twist ws during the performnce mesurements determined with strin gges. See tble 3 nd tble 3b nd section 3.2 of ref. 2.

13 At the drg mesurements on the rods lso different sweep ngles A were used. A slightly different pproch ws pplied: The sweep ngle A ws now mesured on the leding edge of the tipvne. g A is the ngle of the triling edge or leding edge with the g horizontl plin when the ehord line of the blde or the rd is exetly horizontl. A is then eleulted by: A A l es Y g 3.2 Aeeurey The eeurey of the mesured ngles is in the order of 0.5 degree. Two ngles devited: vc of mounting prt 2 nd ve t of mounting h or ver prt 3. In tble 3 the eorreeted vlues re presented. The eeurey ws eheeked by eleulting A,Y nd 8 from the originl ngles 8, Ak nd Y (see tble 1) by the methd deseribed k k in seetion of ref. 1. The mesured vlue of ve of prt 2 ws: h or ve = hor This vlue is lrger thn for prt 1 nd 3. It should be the smllest, beeuse 8 of prt 2 hs the lrgest vlue. The mesured vlue of ve t of prt 3 ws: ver ve = vert The eleulted vlue for 8 with this ve t = ws 8 = ver This devites to mueh from the eleultion for 8 bsed on Sk' Ak nd Y k, whieh give S = Due to the unrelibility of the vlues in tble 3 nd tble 4 the ngles of tble 2 re used for further eleultions.

14 Results The results of the originl built-in ngles re presented in tble 1 nd the clcultions bsed upon these ngles in tble 2. The mesurement ngles nd clculted erodynmic ngles re given in tble 3 nd tble 4. Due to the unrelibility in the mesurement ngles the clculted erodynmic ngles of tble 4 re not used. For ll clcultions the erodynmic ngles of tble 2 re used. In tble 5 A r nd e re given without nd with flpping ngle for different A settings such s used by the drg mesurements of the Kolibrie tipvnes on the rods. A is directly clculted from the mesured A. g

15 References 1. A. Bruining Definition, trnsformtion-formule nd mesurements of tipvne ngles, IW-R510, ISBN A. Bruining Performnce mesurements of the Kolibrie nd FA CT rotor with tipvnes on the full scle experimentl wind turbine, IW-R519, A. Bruining Tipvne drg mesurements on the fullscle experimentl wind turbine, IW-R517, 1986.

16 mounting prt tip degrees k degrees Ak degrees Y k degrees m et degrees Tble 1: The originl ngles of the Kolibrie tipvne mounting prts. mounting prt tip degrees A degrees Y degrees degrees Tble 2: The originl erodynmic ngles clculted from tble 1. These vlues re used for further clcultions.

17 mounting prt vb vert degrees ve vert degrees vb h degrees or 1 ve hor degrees z 1jJ degrees mm Tble 3: Mesured ngles of the 3 Kolibrie mounting prts. 1 eorreeted vlue for mesuring error, vlue from eleultion, bsed on geometry, (mesured vlue ws ve h = ). or Z eorreeted vlue for mesuring error, vlue from eleultion, bsed on geometry (mesured vlue ws ve t = ). ver mounting prt A degrees y degrees degrees tip degrees Tble 4: The clculted erodynmic ngles of the 3 mounting prts for the Liebeck tipvnes of the Kolibrie rotor from the mesured ngles. Not used for further clcultions.

18 ! : = 0 = 4 mounting A A Y A y g f) f) - prt f) degrees degrees Tble 5: The erodynmic ngles without nd with flpping ngle f) of the tipvnes of the Kolibrie rotor used by the drg mesurements on the rods A = A l eos Y. g

19 f) :: 0 0 f) :: 4 0 mounting 8. A Y 8 A Y 8 tlp prt f) f) f) degrees degrees Tble 6: The erodynmic ngles without nd with flpping ngle f) of the tipvnes of the Kolibrie rotor on the bldes used by the performnce mesurements.

20 R=4.375m 1,. I. chord line power blode or centre line of the rod \ I I I I i i Hounfing prt b el R :1.,1.75 ffi_ b I R=4.475m 'J 8km Fig. 1: Drwing of the ttchment of the Liebeck tipvne on the mounting prt of the Kolibrie tipvne.

21 N o N 14 f-- '-- 14 o... co,..-' ' ,,, -..._- ) "-, ('' f i.--y '1 \.\ \, I I. I I ; \ I ['....-' :;.-'.-' :::,.-' i'-.-' co..-' 'P. Ol -.i M Fig. 2 : Dimensions of mounting prt 1 of the tipvne of the Kolibrie rotor.

22 70.j, Hferil Aluminium 51 ST N ' M, N ol Dimensions in mm 0 N CDI -$J CD o lil lil N M N Hounfing prt 2 >-> ld 24 M 14 lil 101 Fig 2b : Dimensions of mounting prt 2 of the tipvne of the Kolibrie rotor.

23 12 -. t--!...- Hteril AI.. ummium 51ST Olmensions in mm 0 N o N (DI I <$- (]) 1" 1" N M N I I -2 -<$- I. -': 0 :;: I I, \::::.::::. \::::. ::::'::::'Il,,\.\ Hounting prt 3 o N o 24 2" '!!. ). M12 /t, (.,,,- ' " \)( ',\ \. \., \ \ I I \ I \ \ \. \ r'-- ::; I"- ::; r'--./ r-- j :::: r--. I'--./ r'--./, M 101 Fig. 2c-l: Dimensions of mounting prt 3 of the tipvne of the Kolibrie rotor.

24 o N 16 '4 I 0 U) U) 0.- N.-. Hounting prt 3 Dimensions in mm 70 Fig. 2c-: Dimensions of mounting prt 3 for the tipvne of the Kolibrie rotor.

25 v rortionl direction b c j 111 V Cve rt v b vert b v Fig. 3 : The horizontl nd verticl position of the tipvne for mesuring the tipvne ngles.

( dg. ) 2 dt. + dt. dt j + dh. + dt. r(t) dt. Comparing this equation with the one listed above for the length of see that

( dg. ) 2 dt. + dt. dt j + dh. + dt. r(t) dt. Comparing this equation with the one listed above for the length of see that Arc Length of Curves in Three Dimensionl Spce If the vector function r(t) f(t) i + g(t) j + h(t) k trces out the curve C s t vries, we cn mesure distnces long C using formul nerly identicl to one tht we