Performance measurements of the kolibrie- and fact rotor tipvanes on the full-scale experimental wind turbine

1989

J

i

.

)1

'

.~

-

)

lAvt/f

...---

--

I)elft

niversiteit Delft

Kolibrie- and Fact Rotor with

Tipvanes on the Full-Scale

Experimental Wind Turbine

A. Bruining

A. Bruining

Delft University Press,

1989

•

Bibliotheek TU Delft

1111111111111

C 1744647

Stevinweg 1 2628cN Delft The Netherlands

By order of:

Delft University of Technology Institute for Windenergy

Kluyverweg 1 2629HS Delft The Netherlands

Report IW-R519 April 1989

Carried out within the Dutch Development Program for

Wind Energy (NOW-2) ; by order of the Management Office

for Energy Research PEO; financed by the Ministry of Economie Affairs.

CIP-GEGEVENS KONINKLIJKE BIBLIOTHEEK, DEN HAAG

Bruining, A.

Performance measurements of the Kolibrie- and fact rotor with tipvanes on the full-scale experiment al wind turbine / A. Bruining. - Delft: Delft University Press. - 111., fig., tab.

Report IW-R519. - Carried out within the Dutch Development Program for Wind Energy (NOW-2); by order of the

Managemen't Office for Energy Research PEO. - Publ. by

order of: Delft University of Technology, Institute for

Windenergy. - Met lito opg.

ISBN 90-6275-421-X

SISO 653.2 UDC 533:621.548 NUGI 834

Trefw.: windmolens; aerodynamica.

copyright

©

by Delft University Press.

No part of this book may be reproduced in any form by print, photoprint, microfilm or any other means, without written permission from Delft University Press.

CONTENTS Summary pag.

4

1. Symbols

₅

10 12 2. Introduction

3.

Apparatus, tests, methods and procedures

3.1 Experimental full-scale wind turbine 12

3.1.1 Installation 12

3.1.2 Kolibrie and FACT rotor 13

3.2. Model configuration 14

3.2.1 Tipvanes 14

3.2.2 Kolibrie tipvane rotor 15

3.2.3 FACT rotor 16

3.3

Instrumentation, data collection and data reduction 16

3.3.1 Instrumentation 16 3.3.2 Camera system 16 3.3.3 Data collection 17 3.4 Tests 17

4.

Results 18

5.

Accuracy 19

5.1 Variation limits for the conditional sampling method 19

5.2 Other errors 20

6.

Comparison measurements and theory 22

7.

Conclusions 24

8.

References 25 Tables Figures 27 32

SUMMARY

This report contains the results of the performance measurements on the Kolibrie rotor with Liebeck tipvanes and the FACT rotor with NACA tipvanes.

The measurements were carried out on the experimental full-scale wind turbine rotor test facility in Hoek van Holland of the Delft University of Technology.

The results are presented in Cp - À plots. The covered range of tip speed ratios was between À =

5

and À = 13. The used blade

o 0

pitch angles varied between 1 and

6

The lift co~fficients on the tipvane varied between CL =

0.5

and CL

=

1.0 for the Kolibrie tipvanes and between CL

=

0.9

and CL = 1.0 for the FACT tipvanes.

Finally the results of the calculated gross power reduced with the measuredtipvane drag characteristics are compared withthè measured power of the rotor with tipvanes in the Cp - À plots. These calculations are in agreement with the measurements.

At moderate lift co~fficients on the tipvane the same power could be measured on the Kolibrie rotor with and without

tipvanes. At high lift co~fficients on the tipvane only negative power output was achieved due to a too high drag level of the tipvane.

Calculations showed that there might be a significant contribution of induced drag.

1. SYMBOLS a A

=

b c b - _S b

₌

c b max b 1 c c _r crb ( = ----:-1

---=D=----:-z-2

p

(QR) S

or ( Q

*

Q J

J

R 1 Z N 2p(Qr) c dr .

o

r

offset distanee of the tipvane of the Kolibrie rotor, see fig. 9a

aspect ratio of the tipvane

distanee between center line mounting part an d l

4

c pOlnt . of the Kolibrie tipvane, see fig. 9a

ave rage span of the tipvane

maximum span of the tipvane, see fig. 7a

span of the tipvane, rect-angular part, see fig. 7a

chord of the tipvane, see fig. 7a

chord of the blade at r

chord of the blade at r

=

blade root location

(m) (m) (m) (m) (m) (m) (m) (m)

chord of the blade at the tip (m)

measured drag coefficient of the tipvane

CD blade visc CD interference CD . stall CD tipvane visc Cp blade drag Cp tipvane drag D D blade D

(=

blade

J

R 1 2 N zp(Qr) c dr

o

r D. = _ _ ---=l.=---_ 1 2 zp(QR) S D. _{l.nter erenee} f = _z z p(QR)

S

D

(=

stall

1

J

R 1 2 N zp(Qr) c dr

o

r D . . tlpvane V1SC 1 2 zp(QR) S L =

---=---1 2 zp(QR) S p gross 1 3 2 zP U nR p = _---=n:.::e::::.:t~_ 1 3 2 zP U nR

average vis\cous blade drag coêfficient

induced drag co~fficient

of the tipvane

interference drag co~fficient

of the tipvane

average blade drag coêfficient

(-)

(

-

)

(

-

)

of the tipvane (-)

viscous drag coêfficient

of the tipvane (-)

calculated lift coefficient

of the tipvane

(-)

losses on Cp due to the

gross

blade drag

(-)

gross power coêfficient,

power extracted from the air (-)

net power coêfficient, avail-able power on the rotor shaft (-)

losses on Cp due to the

gross

drag of the tipvane (-)

measured drag of 1 tipvane (N)

viscous drag of the rotor

D.

_{lnter erence} f D . . tlpvane V1SC L N p gross p net Q r R

s

S _blade

u

= interference drag of 1 tipvane rotor blade

viscous drag of the tipvane

calculated lift of the tipvane

number of rotor blades

gross power, extracted from the air

net power, available at the the rotor shaft

measured torque at the rotor shaft (N) (N) (N) (

-

) (Watts) (Watts) (Nm)

radius of a blade element (m)

radius of the rotor (m)

total surface of the tipvane (m2)

R*(c .

+

c

)

tlp r=Q

1

----~L-~2--~~ surface of 1 rotor blade counted to the shaft (surface of root cut out included) (m2)

surf ace of the rectangular part of the tipvane

AU

€: average 8 8 _nomlna . 1

,

8 8 blade root

zero-lift angle of the airfoil section

flapping angle

tilt angle of the tipvane

specified tolerance of the torque Q for the conditional sampling method

specified toleranee of the wind speed U for the

(degrees)

(degrees)

(degrees)

(Nm)

conditional sampling method

(%)

specified tolerance of the angular rotor speed Q for the conditional sampling method

(%)

blade twist of 1 rotor blade (degrees)

[=8

-8)

ave rage blade twist of the 2 blade root tip

rotor blades

incidence angle of the tipvane

indication of the designed incidence angle of the tipvane

mounting part angle, defined in fig. 9a

blade pitch angle at the root of the rotor blade

(degrees)

(degrees)

(degrees)

(degrees)

8 ref A p cr . tlpvane Q indices a

built-in mounting part angle, defined in fig. 9a

blade pitch angle measured at the reference surface on the connection between the blade

(degrees)

and the flexible hub element (degrees)

= = = QR U N

*

Sblade 2 n

*

R N

*

S 2 n*R

rotor blade pitch angle at the tip

tip speed ratio

yaw angle of the tipvane

air density

rotor solidity

tipvane solidi ty

angular speed of the rotor

indicates the aerodynamic angles

indicates flapping angles

(degrees)

(-)

(degrees) 3 (kg/m ) (

-

) (

-

) (rad/s)

2. INTRODUCTION

The full scale experiments with tipvanes started in 1982 with performance measurements of tipvanes mounted on the flexible Kolibrie rotor blades.

These full scale tests should give a verification of the

principles of the tipvane concept in the turbulent atmospheric flow at representative scale for future commercial applications. Also the experiments should demonstrate that the flexible

tipvane rotor could operate without vibration and flutter dangèr.

The first rotor tested, was the Kolibrie rotor. The metal

Kolibrie rotor blades came from the Dutch manufactured Kolibrie helicopter. This smal I 2 seater helicopter was powered by 2 ramjets mounted on the rotor tips. No modification was necessary to mount the tipvanes.

The tipvanes mounted on the Kolibrie rotor blades had a Liebeck

5055

airfoil section. They were curved to account for the

circular flow.

The best results of the Kolibrie tipvane rotor gave the same power output as the rotor without tipvanes. This was achieved

with the tipvanes set to a moderate lift co~fficient and

consequently a moderate inducted increase of the flow in the rotor plane.

A second rotor system was designed and constructed with the meantime collected experience, the FACT rotor (Flexible Advanced Composite Tipvane rotor). The Kolibrie rotor has a relative small solidity for the desired tip speed ratios and it has a rather high flapping flexibility. This second rotor system and tipvanes were made from aramide reinforced expoxy resine The flexible hub element consists of a carbon fiber.

Two sets of tipvanes we re constructed: one with a Liebeck airfoil section again and 1 set with a NACA 23012 airfoil section.

The FACT rotor was used for the diagnostical experiments to determine why it was impossible to measure a power augmentation on the shaft.

During the manufacturing phase it was realized that

3

dimensional floweffects might impair the performance of the critical Liebeck tipvanes. So the NACA tipvanes we re constructed as a second tipvane set to check this assumption.

These performance measurements formed a part of the diagnostical experiments and were useful, combined with the tipvane drag measurements, wake measurements and performance measurements of the rotors without tipvanes to check the aerodynamic theory.

3.

APPARATUS • TESTS. METIlODS AND PROCEDURES

3.1 Experimental full-scale wind turbine

3.1.1 Installation

The measurements were carried out on the experimental wind turbine rotor test facility in Hoek van Holland of the Delft University of Technology. A photograph and a sketch of the installation is given in fig. la and fig. lb.

The rotor radius is

4.475

m. and the tower height is

15

m. The tiltable tower can be lowered and erected in a few minutes. This gives the possibility for easy access to the nacelle and

rotor system to make modifications during the test, for instance blade pitch changes. (The blade pitch cannot be changed while the rotor is running).

The 40 kW D.C. generator can operate as a generator and as a motor and is controlled by a modified Ward Leonard circuit. During the drag and performance measurements the rotor was kept at a constant rotation speed for a certain time (see also

section

3.3.3),

necessary for the "conditional sampling" measuring method.

The generator is mounted on a spring supported subframe to avoid mechanical resonance problems. During the described tests it was bolted on the mainframe with the springs removed because there were no resonance problems encountered during the tests

described.

A torque meter and an angular velocity meter are located on the shaft between the rotor and gear-box. See fig. 2a, fig. 2b and fig. 2c.

A movable cup anemometer is used for the registration of the wind speed. The wind meter was placed 1 diameter upstream of the

rotor at hub height. See also ref. 1 for a more comprehensive description of the installation.

3.1.2 Kolibrie and FACT rotor systems

The hub sections of the Kolibrie rotor and FACT rotor have flapping and torsional flexibility, but are stiff in-plane. However the torsional flexibility of the hub section is removed by a torsion bar.

Both rotor systems consist of two blades.

Table 1 contains some geometrical data of both rotor systems.

Fig. 3a shows the layout of the former Kolibrie helicopter, from which one set of blades was taken. Fig. 3b gives a sketch of the planform of the Kolibrie rotor blade with the flexible hub

section. The hub section consists of metal blade springs. Fig. 3c gives an impression of the original Kolibrie blade construction and attachment of the blade root on the blade springs of the hub section.

The rotor blades are manufactured of aluminium and have a NACA 0012-H3 profile section. Fig. 3d shows the airfoil section of this NACA 0012-H3 airfoil. It is a modified NA CA 0012 profile. See also ref. 3.

Fig. 3e shows the 2-dimensional airfoil characteristics of the NACA 0012-H3 airfoil.

To reduce the flapping flexibility and buckling of the laminated metal suspension springs a cuff and auxiliary springs were added to the hub section of the original Kolibrie rotor.

This was necessary to avoid too large flapping motions at rather high wind speed when the rotor is not rotating, because then there is no compensating centrifugal force. This problem occured especially at starting up of the the rotor.

The cuff prevented local buckling of the laminated metal suspension springs.

Fig. 4a is a photo of the FACT rotor. Fig. 4b gives a drawing of the FACT rotor with tipvanes.

The FACT blades are constructed of aramide, the flexible hub section is made from carbon fiber. The blades have a NACA 23018 profile section. Fig. 4c shows the flexible hub element of the FACT rotor.

3.2 Model configuration

See for a description of the Kolibrie and FACT rotor the

previous section 3.1.2 and table 1 for some geometrical data of the rotors. Table 2 contains the data of the Liebeck and NACA tipvane sets.

Ref. 1 contains a more extensive description of the rotor systems and the full-scale test facility

The blade pitch angle can only be changèd for each blade separately by adjusting a threaded bar when the tower is lowered; the blade pitch cannot be varied when the rotor is running.

The blade twist € of the Kolibrie rotor depends on Q, due to the

low value of torsional stiffness of the blade. It is measured during rotation by strain gauges. But only with tipvanes mounted there is a significant change in the blade twist € due to

centrifugal loads of the tipvanes. Originally they have no built-in twist. Table 3a and 3b contains these measured twist values of the Kolibrie rotor.

3.2.1 Tipvanes

The Kolibrie rotor can be equipped with tipvanes which have a Liebeck LA 5055 airfoil section. For the FACT rotor there is also a Liebeck LA 5055 tipvane set and a tipvane set which has a NACA 23012 airfoil section.

The airfoil geometry of the tipvane had to be corrected for the circular flow. Theoretical calculations showed that an

appropriately curved airfoil in a curved flow will have

approximately the same airfoil characteristics as the original airfoil in a straight flow. See fig. 5 and fig. 6 for the original and curved airfoil sections of the Liebeck and NACA tipvanes.

Fig. 7a gives the planform, some definitions and dimensions of the tipvane. Table 2 lists some dimensions of the tipvanes. The tip on the upstream side has a specially designed shape to avoid a tip suction force in the tipvane span direction. This force is created by the tipvane trailing vortex. Such a force has a component opposite to the rotation direction and thus increases the drag level of the tipvane.

See fig. 7b, fig. 7c, fig. 7d and fig. 7e for the shape of this anti suction tip of the Liebeck tipvane and fig. 8a, fig. 8b, fig. 8c and fig. 8d for the NACA tip.

3.2.2 Kolibrie tipvane rotor

Table 3a gives an overview of the resulting aerodynamic tipvane angles of the measured configuration of the Kolibrie tipvane rotor.

Ref.

4

gives the explanation and ref.

5

the data of the tipvanes angles.

Also different blade pitch settings were used (see table 3a).

Three mounting parts were used for the tipvane to achieve the different lift levels on the tipvane itself. Fig. 9a to fig. 9d2 show the construction drawings of the mounting parts.

Table 1 and table 2 gives some geometrical data. See also section 3.1.2 for the rotor itself.

3.2.3

FACT rotor

Table 4a summarizes the configurations measured with the FACT rotor.

Ref. 4 gives the explanation and ref.

6

gives the data of the tipvane angles.

Some geometrical data is collected in table 1 and table 2. See also section

3.1.2

for the rotor itself.

3.3

Instrumentation, data collection and data reduction

3.3.1

Instrumentation

The standard instrumentation and data collection method was used. A detailed description is given in ref. 2.

A brief description of some features used for the measurements are given here.

The wind speed is measured at hub height by a cup anemometer mounted on a mobile tower. The tower is placed at 1 rotor

diameter distance in the upwind direction of the rotor. A delay time, based on the average wind speed, is accounted for during the data collection to get the best possible correlation between the measured wind speed and the data taken from the rotor.

3.3.2

Camera system

In front of the rotor shaft a small extension tower could be mounted. This tower rotates together with the rotor. On this tower a black and white television camera or photo camera can be attached.

The television camera is powered with a battery pack. The signal is transferred via a slip ring. This works very satisfactorily. A winder transports the film of the photo camera, the shutter is released by a wireless signal.

The camera gives a picture of one tipvane and rotor blade. It is also possible to position the camera so as to cover the low pressure side of the rotor blade.

The television picture can be used for safety monitoring or to show the flow pattern of the tufted tipvane or rotor blade. Also the television picture is usable for estimating the flapping angle of the rotor blade during rotation.

3.3.3

Data collection

The data collection was done by a method known as "conditional sampling" (see also ref. 1). This sampling method selects and stores the signal values only when the test conditions are relatively steady. Criteria for the "steadiness" are based on the rate of change of the rotor speed, wind speed, wind

direction and torque. See section 5.1 for the values used of these criteria.

The signals therefore were continuously monitored. A HP 9826 micro computer then selected the data points falling within the specified variation limits, stored the selected data on a micro floppy disk and printed the results in tables and graphics for a quick look.

A 6-channel pen recorder recorded continuously the wind speed, torque, angular rotor velocity, a second wind speed, wind direction and the blade torsion signal.

Every time the micro computer selects a data point a mark was recorded on the pen recorder. Thus a good correspondence was obtained between the stored data points and the output of the pen recorder.

3.4

Tests

An overview of the measured runs is given in table 3b and table 4b respectively of the Kolibrie- and FACT rotor.

With the Kolibrie rotor a number of experiments have been

carried out with filling parts in the blade tipvane junction to attempt to reduce interference drag. Also a Liebeck tipvane with a little bit shorter span

(b

= 1.45 m.) was used.

Both kinds of experiments didn't show a significant difference with the other tests. The data of these tests are not included in this report.

4.

RFSULTS

The results of the performance measurements of the Kolibrie- and FAC Tipvane rotor respectively are given in fig. 10 to fig. 12c and fig. 13 to fig. 14.

5.

ACCURACY

5.1 Variation limits for the conditional sampling method

In the conditional sampling method there were toleranee ranges specified for the unsteadiness of the measured data during a specified measuring time. The sampling rate used for the data was

4

Hz.

In order to be considered as a valid data point, the variation during 2 seconds (Kolibrie) or

3

seconds (FACT) shouldbe less than:

± 15degrees for the wind direction

AQ ± 1

%

for the angular velocity Q of the rotor (called ~)

AU

± 10

%

for the wind speed U (called

-U)

and

± 10 Nm for the torque on the rotor shaft (called AQ).

For the Kolibrie rotor measurements with mounting part

3

the

o

toleranee ranges for the wind direction was set at ± 20 and AQ was set at nearly

O.

± 10 Nm. variation on the torque corresponds with about 10

%

of the average torque.

A is calculated from: A ± AA Q(l ± AQ) Q = const.

*

---~-U(l ± AU) U

As a consequence the variation in A due to the toleranee ranges is: AQ Q + AU

U

Cp is calculated with: = ± 11

%

Cp ± _ACp = const.

*

(Q ± AQ)

*

Q(l ±

~)

_

3

u

3

_{* (}

_{1 + AU}

₁

U

So the variation in Cp due to the tolerances ranges of the conditional sampling method is in the order of:

AQ+

Q

AQ AU

Q +

3

U =

40

%

When one valid data point is recorded the computer program waits 2 seconds (Kolibrie rotor measurements) or

3

seconds (FACT rotor measurements) before the procedure is repeated. If there were no such a delay time there would be the chance that the next data points will be collected with the sampling rate, because - if the conditions are steady enough - all the next data points may satisfy the specified tolerance ranges. This is not an error in the sense that the measured value deviates from what it should be, but rather it overpronounces a certain measured value, especially in a graph or in aregression analysis.

5.2 Other errors

There are more possibilities for errors than the causes mentioned above:

- A cup anemometer accelerates more quickly than it decelerates, so that it behaves more or less as a peak value meter. The effect depends on the wind spectrum, but how big its influence is on the indicated wind speed, is not yet known. Also it is unknown if the conditional sampling method eliminates this error partly or entirely.

A first estimation of this instationary effect was made in the wind tunnel with a wind speed variation of

3

± 1.5 mis at a frequency of 1.2 Hz. It indicated a 10

%

too high reading. The actual frequency at the wind meter located in the wake will be in the order of

3

Hz, so the effect might be even larger. Attention has to be paid when wind measurements in the wake take place.

- The wind direction has some influence on turbulence intensity, because the surroundings are not the same for all directions, for example due to the presence of trees and buildings.

- An ave rage delay time of the wind speed is used for the data obtained from the wind meter that was placed before the rotor

disco The wind meter reading might thus not always correlate very weIl with the actual wind speed at the rotor disco - The data from the wind meter was sometimes less accurate,

because the wind meter was not every month recalibrated and there was some change in the calibration function.

A linear relation was used between the electrical output of the wind meter and the calculated wind speed.

The maximum possible error in the calibration was

4

%

(larger influence at the higher wind speeds) and

5

%

in the

zero-offset (the largest error occurs at the lower wind speeds). These maximum errors could occur just before a new calibration of the wind meter was carried out in the wind tunnel.

An error in the wind meter calibration causes a systematic deviation, not an increase of the scatter on the measured values.

A small offset error is possible in the torque meter, because there is a small temperature influence on it. In the worst cases with a big temperature rise during the day the torque reading decreases at most with 10 Nm. This means that in motor operation the measured torque is a little bit more negative than it actually is.

- The accuracy in the tipvane angles is not better than 0.5 degrees. The margin in the yaw angle A of the tipvane is even

o

1 . In this way there is a deviation introduced in the calculated values of CL and CD of the tipvane. See also section 5 of ref. 5 and ref. 6 about the accuracy.

- The corrections for the variations of air temperature and air pressure and their influence on the air density during the data reduction process were less than

3%,

so they we re neglected.

- The actual tipvane dimensions differ a little bit from what was used for the calculations.

The actual chord of the NA CA tipvane of the FACT rotor is a factor 0.447/0.443 larger and the actual area is a factor 0.7081/0.6955 larger.

22

-6.

COMPARISON MEASUREMENT AND THEORY

The gross power and the induced drag were calculated for the configurations listed in table 1 and table 2.

The net power coêfficient can be calculated by:

where Cp and

=

Cp gross = blade drag - Cp blade drag

- C

Ptipvane drag

C

_n

₊

_{C n )}

*

1

₄

_crblade

*

A

3

blade stall C

n

_{3tipvane drag} =(C

n

_i +C

n

_{tipvane visc}

.

+C

n

_interference

)

*

cr tipvane

*

À

The solidities are defined as:

cr . _t1pvane

=

=

Sblade is counted to the rotor shaft, with the surface of the root cut out included:

S = R

* (

blade

Until present the

Cn.

cannot calculated correctly. In fig.

10

to

1

fig.

14

an attempt is shown to calculate Cp of the performance measurements by using the measured drag of the tipvanes on the

For this purpose the CD and CD together

tipvane visc interference

are replaced by the value of CD - CD. collected from the drag

l

measurements. The value of CD - CD. is calculated from the

l

CL - CD graphs of the tipvanes in ref.

7

by substraction of the calculated induced drag from the measurements. CD. is calculated

l

by the measurements. CD. is calculated by the method described l

in ref.

8.

CD - CD. varies a little with À. For this a linear function is

l

assumed. The assumption of

C -C = CD + CD

D Di tipvane visc interference

is only correct wh en the interference drag of the rod-tipvane differs not to much from the interference drag of the tipvane rotor blade configuration. Replacement of the

CD. + CD + CD

l tipvane visc interference

by the measured CD takes not the difference in the calculated CD. in account, so this is less accurate.

1

In the method above used, the effects of the miscalculation in CD. of the rod tipvane configuration and rotor blade tipvane

l

7.

CONCLUSIONS

1. The (induced) drag of the present tipvanes is too high to achieve high net power output. There is no large difference between the Liebeck 5055 and NACA 23012 airfoil section. 2. At moderate CL values the rotor with and without tipvanes

gives the same power output.

3.

The method by calculating the net power output using the measured drag of the tipvanes shows areasonabIe good agreement with the measured power.

So it will be possible in the future to tackle the drag problem of the tipvane by verifying the calculations by meanly drag measurements with tipvanes on rods. Also is in all probability the power extracted from the air (gross power) correct calculated. This is endorsed by velocity measurements in the wake

~

m. behind the rotor disco

8.

REFERENCFS 1. Van Bussel, G.J.W. Kooman, J.L. 2. Overgaauw, R.H.J.

3.

N. N. 4. Bruining, A 5. Bruining, A. 6. Bruining, A. 7. Bruining, A

Rotor performance testing at the Delft University of Technology, paper presented at the European Wind Energy Association, Italy 7-9

October 1986.

Vermogensmetingen aan een windturbine in de buitenlucht,

(in Dutch), TU Delft, November 1985.

National Aerospace Laboratory. Appendix of correspondence to NIV dd. 21-1-59 no. A/330.

Definition, transformation-formulae and measurements of tipvane angles, IW-R510, 1987. ISBN 90-6275-424-4.

The angles of the Kolibrie rotor tipvanes on the rods and blades. IW-R515, 1988. ISBN 90-6275-496-1

The angles of the FACT rotor tipvanes on the rods and blades. IW-R516, 1988. ISBN 90-6275-522-4

Tipvane drag measurements on the full-scale experiment al wind turbine,

8.

Van Holten, Th.

9.

Bruining, A

An aerodynamic theory of wind turbines with tipvanes.

IW-R513, 1985.

Performance measurements of the Kolibrie and FACT rotor blades without tipvanes on the full-scale experimental wind turbine.

N R 1 )

i

blR I I C IR I

!

r , ctip/R I I b I C r=O _I C

I

r ctip €: profile a i 0

I

C

_Q a

I

FACT rotor (

-

) 2 (m) 4.475 (

-

) _0.6927 (

-

) 0.0856 ( - ) _0.0670 (m) 3.1 (m) 0.42 (m) 0.383 (m) 0.30 (degrees) 7.5 (

-

) NA CA 23018 (degrees) -1.5 -1 (degrees ) 0.1

1) Radius with tipvanes

o , i i i I i

2) with tipvanes: 0.5 for Q = 60 rpm 3 for Q = 130 rpm

Table 1: Some data of the Kolibrie and FACT rotor.

Kolibrie rotor 2 4.375 0.7657 0.0571 0.0571 3.35 0.25 0.25 0.25 depends on Q 2) 0012-H3 -1.5 0.1

Liebeck Liebeck NACA

tipvane tipvane tipvane

Kolibrie FACT FACT

rotor rotor rotor

airfoil type Liebeck Liebeck NACA

I

LA

5055

LA

5055

23012

a o degrees

-4.5

-4.5

-1.5

,

_-1

C Q

I

degrees

0.1

0.1

0.1

a

R

m

4

.

475

4.475

I

4

.

475

b

I

m

1.635

1.635

1.65

max b

1

I

, m

1.45

1.45

1,45

I c

I

m

0

.

44

0.443

0.443

Sl 1 m

2

0.638

-

0.642

0

.

642

S m

2

0.6798

0

.

6955

0.6955

-b m

1.545

1.57

1.57

b/R

0.3453

0.3508

I

0.3508

c/R

0.09832

0.09899

0

.

09899

A

_3.51

_3.54

_I

₃

_.

₅₄

1

Table 2: Some data of the tipvanes used for the calculations and data reduction.

file mounting S

ref € StiP A _a[3 r _a[3 S _a[3

number part

_1--'

_.

_..

_-

_--

_-

_..

_-

_

.. _ ... -_._---....

-

_{- - - - ----}- -- ---. ---~

degrees I degrees degrees degrees degrees degrees

!

i

D1207835

!

1 -1.25 -2.5 +1.25 18.35 19.51 8.33 I

I

D1207836

i

1 -1.25 -2.5 +1.25 18.35 19.51 8.33

!

_{1-'---' - - ' - ' ---- - --.- ------.. ,--.. --. ----- ... - -} f---.-- ---

I

._- --·----r-··--- -- --- -D2710832 I 2 23.57 16.34 18.10 D2710833

!

2 3.0 0.2 2.8 23.57 i6.34 18.10

3.0

~

o.2

2.8

, _{- --_. --.-'--" _.} -_.+----_.".-

---

_

... -

.

-

-

-·--·--

-

--

l

, D2106831 \ ₃ 1.0 0.2 0.8 12.79 17.10 15.85 D2106832 I 3 1.0 0.2 0.8 12.79 17.10

.

L _

_

_

_

___

._

....

_ - - -

-

_

.. _---- _ ._ - -- -_._----_ ..

_-D2006831 3 3.0 -0.2 3.2 15.13 17.14 D2006832 3 3.0 -0.2 _3·2 15.13 17.14 D2006833

I

3 3.0 -0.2 3.2 15.13 17.14 D2006834

I

3 I 5.0 -0.2 5.2 17.09 17.18 D2006835 I 3 5.0 -0.2 5.2 17.09 17.18 I

Table 3a: Angles of the tipvanes and rotor blades of the Kolibrie D

performance measurements for aflapping [3 = 4 .

15.85 15.68 ! 15.68 I i 15.68 i ; 15.54 15.54 :

file number Q rpm degrees range U mis

D1207835

100

-2.0

3.4 - 10.3

D1207836

110

-2.9

I

3.5 - 10.5

I 1 - - - -- -... - ... ---.-. --.... - - - - -.- ... . ... 1 . ... -... -... .... .

D2710832

100

0

.

2

I

4.3 -

8.2

I--

_

D_2

_

71_0_8

_

3_3--f

__

..

l0

_

._

0

__

.

c - -

O. 2

~

4.9 -

9.3

D2106831

70

!

0.1

I

2

.

7 -

4.8

80

I

0.0

2.6 -

5.1

89

!

-0.1

I

2.7 -

4.4

~---+-. __

.--r-

'

i

88

I

0 . 1

I

3 . 5 -

4

.

0 i

I

77

0.2

I

2.4 -

4.2

D2106833

60

0.4

I

5.8 -

6.3

f - - -- -- - - ----f- -- - - + - - -- - - j ... - -. - - - - -

-D2006831

D2006832

D2006833

D2006834

D2006835

80

80

100

100

79

80

-0.1

-0.1

-0.3

-0.4

-0.1

-0.2

2.9 -

8.2

3·0 -

9.3

3.6 -

8.9

4.0 -

9.6

3.2 -

8

.

6

6.4 -

8.8

Table 3b: Overview of the measured runs of the Kolibrie tipvane rotor.

file numbers DZ1212841 DZ1211842 DZ1212842

DZ1212843 i

S _bladeroot degrees 8.3

I

13.6

rotor e:: degrees 7.5 7.5

blade _Stip degrees 0.8 6.1

A degrees 8.78 13.42 aR> tipvane A degrees 24.52 24.60 aR> A degrees 17.48 17.03 aR>

Table 4a: Angles of the FACT rotor with the NACA tipvanes for a o

flapping angle of R> = 5 and 2 different blade pitch settings.

file number Q range U

rpm. mis DZ1212841 70 1.8

-

4.5 DZ1212842 80 2.3

-

4.3 DZ1212843 50 1.5

-

4.4 - . --- ---_._ - ._---_ ... __

.

_

.

_._

.

_-DZ1211842 80 4.3 -10.0

Fig. la: Full-scale windturbine test facility, tipvanes mounted on Kolibrie bladesi 9 m diameter.

Fig. lb: Sketch of the full-scale wind turbine test facility indicating component lay out.

UHIVERSAL JOINT

INTERCOM

STRAIN GAlG:S

o

Fig. 2a: Nacelle lay out of the full-scale test facility.

KJl'OR

GmERAroR

BRl\KE

W

Fig. 2b: Inside view of the front part of the nacelle of the full-scale test facility showing the sliprings and signal transmitter and

receiver.

Fig. 2c: Torque and tacho meter and counter of the full-scale test facility

c::...1-=:::>

~

MAJOR COHPONENTS

1 - two bladed, bonded-metal rotor with two 60 ehp ramjets

2 - universal, central box-beam chassis, suspended from the rotor with double

main-bearings

3 - tail rotor for directional control only,

driven from main rotor and fixed to short tail boom

4 - instrument-box with panel 5 - starter-engine

6 - one or two seats

7 - one to four cylindrical tanks.for fuel or spray-liquid

8 - skid undercarriage

Fig. 3a: Sketch of the Kolibrie helicopter indicating the major

components, from NHI.

w

0"1

... W

r---r-~[

ro

0

.- _~ Lf) 70 N

"

"-

0 .-1 U ~ ..- ..- I--Lf) i!!.,.0 0:-M I 0

8

'f

N N U ~ ..-250 _.",

"-0 Lf) M M Dimensions in m m

'"

"-

0 M 275· lf) 1. ~

,..-~

16 u ~

H JOIO$

Fig. 3e: A view of the original root eonneetion of the Kolibrie blade (from NHI) .

National Aerospace Laboratory NLR

E __

·

~~_. ~_'==_'

=-_.

--=--

'

=~~--""=~

~

Profile of the NHI H

3-rotorblade according to NHI dd 6-5-'58

.z

'772m p,()()(} .3,1:15 é • .260 1.2,~ 18,7-JO ~~ .37.t)():) .50,~ 62,~ 75.tW .Q?,~ tM.a:» ~.a:» 175,axJ .ta?.tW .u~a:t' .M(J.taJ y~ .,.,.n

.t~

o,o%\? 'lal? "':7JO 6.!56() t.. ti 8,9<X' :. ₀ ~M:1 IQ .... ti 11.7(X) IQ t.. 13,.3!JO

...

u lIJ ~.Y.\? t.. Ol ....

...

flll,8~ ti t: ~ .... ~a:l7 flll,5tXJ :... Ol ~ ff,~ -",1oW g,óa:J - g,a:l7 ,/,tJ50 _ 5.2!!O 6.tJ.2t) - I,OW ~2!!iO .. a.ba7 1fe/S5~L ~.".m

Fig. 3d: Original airfoil seetion of the Kolibrie rotor blade (from ref. 3).

;Y,Rc,q

0012

Fig. 3e: Calculated airfoil characteristics of the Kolibrie rotor blade (from reL 3)

o

~

~

o

Fig. 4a: Full-scale field test facility, FACT rotor with NACA tipvanes. The TV camera is mounted on the hub.

/ '

,

/ /

I

K

i

Fig. 4b: Construct ion drawing of the FACT rotor.

,

I

,

I

I

,

I

I

I

,

I

,

I

,

I

,

I

Dimensions in mm

\=;=

I

,

I

,

I

I

,

I

I

,

I

'=i==!

\

I

I

@)

:

~

J

_ _ _ ~ _ _ .l _ _

+-

__

Fig. 4c: Construct ion drawing of the carbon fibre flexible hub element

--

---

î-

--~

-

----V::::-'" IB. 0

I~

I~

"

,

..,

..,

/ /

"

,

,

:! B.0

~~

-IB. 0 -2l!. 0 0.0

---

- -

-' - - - - -

-ut0 20.0 32.0 4B. 0 50.0 60.0

Fig. 5: The original airfoil section (----) and the curved airfoil section (----)

of the Liebeck 5055 tipvane. R/c

=

10.0.

...

--

-

-

~

----

-

-- -70.0 ea.0

-

---.: ~ -_-:...-:.. ... ~

-90.0 100.0

..,.

..,.

lB.B~I

__________

~---~---~---+---r---;---+---r---~---~

V

... -

r-:::. -

-""

-

---"

-

-iI - - - - -B.B - - ~

"'::-:-:--

_---~--

~

-

---

-

----

---

----lB.B~1 ---+---~---~---r_---r_---+_---+_----~--~---~---~

-2B.BLi ____________

~

____________

_ L _ _ _ _ _ _ _ _ _ _ _ _ _ L _ _ _ _ _ _ _ _ _ _ _ _ _ L _ _ _ _ _ _ _ _ _ _ _ _ _ L _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ ~ B.B JB. B

2B. B

3B. B 4B. B

SB.B

BB.B 7B. B

Fig. 6: The original airfoil section (----) and the curved airfoil section (----) of the NACA 23012 tipvane. R/c

=

10.0.

SB. B 9B. B

IBB.B

~

c

Mounting hole in the low pressure surtace ot the Liebeck tipvane ot the Kolibrie rotor.

:::::815mm

:::::160mm

:::::30mm :::::835mm

b_max

Fig. 7a: Planform ano dimensions of the tipvane.

View of the low pressure side. The indicated mounting hole is from the Liebeck tipvane of the Kolibrie rotor.

""

""

₈ ""

""

₇

""

""

6

""

~

""

UI 5

""

""

4

""

""

3

""

2 ) oirfoil

""

~ cross- section _number

440

Fig. 7b: View of the high pressure side of theupstream tip of the Liebeck tipvane. Dimensions in mm Dimensions in mm 205 185 10 . 22 22 22 22 22 22 22 21

---'-..,.

.

9'____

I

.----, _____

oirloil

,'----,---

65 cross-section number

.---,---2

Fig. 7c: View in the spanwidth direction of the upstream tip of the

Liebeck tipvane (indicatedwith A-A in fig. 7a).

low pressure side

ol the tipvone

high pressure side

airtoil cross-sec tion

):~r

9<

»

• reference points

sC

•

•

:::::::>

C

~

7

•

•

c=

~

6

•

•

5

c::::

•

•

~

~ ~

4

•

_•

ç

.

~

3

•

_•

2

•

_•

high pressure side 1

65mm

•

•

4t.Omm

Fig. 7d: Airfoil cross-sections of the upstream tip of the Liebeck tipvane. Fig. 7b and fig. 7c indicate the positions of these cross-sections.

1

airtoil cross-section

. number

high pressure side

Fig. 7e: Combined drawing of the airfoil cross~sections of the upstream tip of the Liebeck tipvanes.

Fig. 7b and fig. 7c indicate the positions of these cross~sections.

..,.

Dimensions in mm N

...

9 N N 8 N N 7 N N 6 N _~ N ₀ 5 N N 4 N N 3· N 2 ) oirfoil N N cross-section N 443

Fig. Ba: View of the high pressure side of the upstream tip of the NACA tipvane.

200 24 22 22 22 22 22 22 22 22

~

/---'---.

oirloil

~

cross-section

~~

number 5 4 " -3 2

Fig. Bb: View in the spanwidth direction of the upstream tip of the NACA tipvane (indicated with A-A in fig. 7a).

number

Dimensions in mm

low pressure side ol Ihe tipvone

53

high pressure side

airfoil

gc

•

•

cross- sec tion (

• reterence points number 8

<::::::

•

_•

_•

•

--.

7

<:::::

_•

_•

=:...

6

<:::::

_•

_•

5C

•

•

4C

•

•

3e

•

•

high pressure side

1 _53mm

•

•

low pressure side 443mm

Fig. Be: Airfoil eross-seetions of the upstream tip of the NACA tipvane. Fig. Ba and fig. Bb indieate the positions of these eross-seetions.

o top

low pressure side

o _o

high pressure side

Fig. 8d: combined drawing of the airfoil cross-sections of the upstream tip of the NACA tipvane. Fig. 8a and fig. Bb indicate the positions of these cross-sections.

V1 N

780mm

Fig. Be: Detail of the rnounting construction of the Liebeck tipvane on the FACT rotor blade.

V1

\

R=4.375m I

I

Hounfing part 1

I

_i

I

i

i

R =4.475 m_ 9km

Fig. 9a: Drawing of the attachment of the Liebeck tipvane on the mounting part of the Kolibrie tipvane.

2 3 b a 99 107 103 b

el

99 4° 99 14° 99 11°

I

R=4.475m

"/

U1 .I:::>

Dimensions in mm

i

_I

~~

(0

I®

I 114

CDI

~o

Lnl Lnl 0 ... N ...

-è-14

35

I

I

co N oNI I '- \. \. \. '- \. '- \. '- \. \. \. \. \. '-\. \. \. '\.

..

Hounting part 1 24

-1-,

M12

,k

( 0" - ~ (0 ') I \...y- ;-.\ I \ \0 \ \

i \

I I I 0 I I : ~ t ' ~ 40 94 75

Fig. 9b: Dimensions of mounting part 1 of the tipvane of the Kolibrie rotor.

'!2 Ol ~ M lJl lJl

CDI

N M N

I

-r

N '

.

~I Haterial Al _Do ° ° ummium 51S! /mens/ons in mm 0 N M

-$

16

J

®

~o l i l _lil

I

_ol

CD

::: ~ I 14 36

Houn ting part 2

24 \ M12 /\"

,t--y\( \"',

( 0 " ' \

\ \ \

\

\\\

\ ° \ _14° 101

Fig. ge: Dimensions of mounting part 2 of the tipvane of the Kolibrie rotor.

~

~

M

V1

CDI I

(0-~ -2

-<$-J

_M

I

N 0 I1 N

II®

~II ~

~I

0 ::: ~ Haferial Aluminium 51 ST Dimensions in mm Hounfing part 3 , \ M12

/+,~)\"

( . '1 . '1

,

\

_I \ _\

,

_I \ _I

\ \

_{. I} I I I \ I I I I \

::bt~l-- \~

40 7S 101 0 N

@

~

14

~

--\.\ 24

~

~ '- _~. ' -' - . /

:::

:::::

~l

' - . / ' - ../

Fig. 9d-l: Dimensions of mounting part 3 of the tipvane of the Kolibrie rotor.

®

14 24

~

~

o ~ ~ V1 -..J

70 70 lJ) 0 .-- N .--Hounfing part 3 Dimensions in mm

Fig. 9d-2: Dimensions of mounting part 3 for the tipvane of the Kolibrie rotor.

1.20 ---~---~---~

KOLIBRIE

rotor

FILE: 01207835 +

01207836 a HOUNTING PART 1. _9ref=-1.2So

SEE TABLE 3a 0.80 ~---+---~--~~r---r---1 (Otipvane 0.40 Cp

I

+

+ ++(+

0+

+ visc + 0 4 0 _(Pnet 16 • À ₊ 0 _{0 0} + + 0 0 0 0 _{+ +} 0 0 -0.40 0 0 0

+cP°

-0.80

Fig. 10: Performance measurements of the Kolibrie rotor with Liebeck tipvanes and compared with calculations.Break even measurements.

r---~---~---~

KOLIBRIE

rotor

FILE: 02710832 + 02710833 0 MOUNTING PART 2. 9_ref=+3° SEE TABLE 3a 1.20 ~---~---~---~----,---~ 0.80 r---~---~~---_+---~ 0.40 ~---~~~----+_----~--~~~---;_---~ Cp

1

o

4 12 16 ----.~ À COblade vi sc -0.40 ~---~---~~~~~~---+---; -0.80 ~---~---~---~---~---~

Fig. 11: Performance measurements of the Kolibrie rotor with Liebeck tipvanes and compared with calculations.

1.60 ~---~---~---~

KOLIBRIE rotor

FILE: 02106831 + 02106832 0 MOUNTING PART 3. 9_ref=+1° SEE TABlE 3a 1.20 ~---~---+---r~---~ 0.80 ~---~--~~---~--~~---+---~ 0.40 ~---~~----+---~---;---~ Cp

r

Co tipvane visc o 0 4 8 12 16 ---+ À COblade visc + + -0.40 + CPnet

+,

-0.80 ~ ______________ ~ ______________ ~ ______ ~~~n~ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~

Fig. 12a: Performance measurements of the Kolibrie rotor with Liebeck tipvanes and compared with calculations.

1.60 ~---~---~---,

KOLIBRIE

rotor

FILE: 02006831 +

02006832 0

02006833 •

MOUNTING PART 3. 9 ref=+3° SEE TABLE 3a 1.20 ~ ____________

-+ ______________

~

________

~L-~.-

____________

~ 0.80 ~---+---~---r---i 0.40 ~---~~~----~--~---+----~---+---~ Cp

I

Co . . hpvane ViSt

o

4 16 - - -•• À COblade vist -0.40 ~---+---4-~~~~----~---~ o D -0.80 L-______________ ~ ________ ~----~---~~----~---~

Fig. 12b: Performance measurements of the Kolibrie rotor with Liebeck tipvanes and compared with calculations.

1.60 ~---r---~---~

KOLIBRIE rotor

FILE: 02006834 +

0200683!S D

MOUNTING PART 3. 9_ref=+So SEE TABLE 3a 1.20 ~---~---~~---~ïï---~ 0.80 ~---~~---~--~~---+---~ 0.40 ~---~----~--~---r---~---~---~

Cp

r

(0 tipv ane visc

o

4 8 16

- - - ' •• À

-0.40 ~---~---~~-ft~---+~~---~

-0.80 L -______________ ~ ______ ~---~---~~~--~---~

Fig. 12c: Performance measurements of the Kolibrie rotor with Liebeck tipvanes and compared with calculations.

FACT

rotor

FILE: 021212841 + 021212842 a 021212843

*

etipC +0.80 SEE TABLE 4a 1.20 r---~---~---~---~ Cp gross 0.80

0.40~---)[~~~~~~~----~---i---~

Cp Co tipvane vist

o

4 12 16 - - - - 1 •• À COblade vist

*

*

-0.40 ~---+_---~~~~~~---~---~ -0.80

*

*

*

Fig. 13: Performance measurements of the FACT rotor with NACA tipvanes and

1.60 r---~---~---__,

FACT rotor

FILE: 021211842 + 9tip=+6.1° SEE TABLE 4a 1.20 r---~---~---~---~ 0.80 r---~---~~---

__

~_+---~ 0.40 r---~----~~---_++_---~---~ Cp

Î

- -.... À

o

.

4 16 + + COtipevane -0.40 J - - - f - - - I - \ - - I t - - - 4 - - l r - - - I COblade visc -0.80 ~---~---~---~--~--~---~---~

Fig. 14: Performance measurements of the FACT rotor with NACA tipvanes and compared with calculations.