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Kaplan turbine
Jebba, Nigeria
*Q = 376 m3/s*H = 27,6 m*P = 96 MW
D0 = 8,5 mDe = 7,1 mDi = 3,1 mB0 = 2,8 m
Machicura, CHILE
*Q = 144 m3/s*H = 36,7 m*P = 48 MW
D0 = 7,2 mDe = 4,2 mDi = 1,9 mB0 = 1,3 m
Outletdraft tube
Outletrunner
Inletrunner
Outletguide vane
Inletguide vane
Hyd
raul
ic e
ffic
ienc
y h
Flow rate Q
Runner blade angle = constant
Hydraulic efficiency
Hill chart
c1
v1
u1
c2 v2
u2
Hg
cucu 2u21u1h
Pressure distribution and torque
LiftLift
DragDrag
Torque
Arm
LL
DD
c
LChord
4
FLift
FDrag
v
AVCF
AVCF
DD
LL
2
2
2
1
2
1
Blade profile data
L
D
C
C
Angle of attack
Angle of attackAngle of attack
Average relative Average relative velocityvelocity
v
Pressure distribution and torque
Pressure side
Suction side
Cord length, l0,24 · l
Single profile
Cascade
The pressure at the outlet is lower for a cascade than for a single profile. The cavitation performance will therefore be reduced in a cascade.
Radial distribution of the blade profile
CL =Lift coefficient for a cascade
CL1 =Lift coefficient for a single profile
The ratio t/l influences the lift coefficient in a cascade. The cord length for a blade will therefore increase when the radius becomes increase
Radial distribution of the blade profile
Flow in the axial plane
The figure shows blades with two different design of the blade in radial direction. This is because it will influence the secondary flow in the radial direction
Main dimension of a Kaplan turbine
n
o Q
1 .5
C m l = 0 .1 2 + 0 .1 8 0
Cm
l
2 .00
0
0 .5
( tiln æ rm e t)
1 .0
2 .5 3 .0
m1
n
m1
22
n
c
4QD
c4
dDQ
Diameter of the runner
Height of the guide vanesand runner diameter
0 .4
0 .3300 400
n s
B /D0
d /D
d/D
, B
/D0
500 700600 800 900
0 .5
0 .6
0 .7
45n
s H
Pnn
Gap between hub and ring and the runner blades
Gap between the blade and hub
Gap between the blade and ring
S p a lte å p n in g x = 1 0 0 0 s /D
Vir
knin
gsgr
ad
00 .8 0
0 .8 5
0 .9 0
1
s = x 10 d- 3
2 3 4 5 6
Eff
icie
ncy
Gap
Runaway speed
k a v itas jo n sk o eff is ien t
Rus
ning
stal
l/nor
mal
turt
all
Voit h
Cavitation coefficient
Run
away
spe
ed
H
H10 S
The figure shows different runaway speed at different runner blade openings. The runaway speed is dependent of the cavitation as shown in the figure
Hill chart
Example
P = 16,8 MWH = 16 mQn = 120 m3/sn = 125 rpm
• Find the dimensions D, d and Bo
• Given data:
93,178,674,0Qn
o
sm7,171682,92Hg2
srad1,13
60
2125
60
2n
1m74,0
sm7,17
srad1,13
Hg2
2
3
nm78,6
sm7,17
sm120
Hg2
Speed number:
Diameter, D:
467,018,012,01 omc
mc
QD
m
n 3,4467,0
478,64
1
Diameter, d:
59016
22826125
4545
m
Hprpm
H
Pnn
ns
0 .4
0 .3300 400
n s
B /D0
d /D
d/D
, B
/D0
500 700600 800 900
0 .5
0 .6
0 .7
m9,145,0Dd45,0D
d
Height, B:
0 .4
0 .3300 400
n s
B /D0
d /D
d/D
, B
/D0
500 700600 800 900
0 .5
0 .6
0 .7
m76,141,0DB41,0D
BO
O
Number of vanes, z:
95,0t
l
5z
Num
ber
of b
lade
s z
