kaplan turbine - · pdf filepressure distribution and torque pressure side suction side 0,24...
TRANSCRIPT
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
ien c
y η h
Flow rate Q
Runner blade angleφ = constant
Hydraulic efficiency
Hill chart
c1
v1
u1
c2 v2
u2
Hgcucu 2u21u1
h ⋅⋅−⋅
=η
Pressure distribution and torque
LiftLift
DragDrag
Torque
Arm
LL
DD
c
LChord4
α
FLift
FDragv
AVCF
AVCF
DD
LL
⋅⋅⋅⋅=
⋅⋅⋅⋅=
2
2
21
21
ρ
ρ
Blade profile data
L
D
CC
Angle of attack
Angle of attackAngle of attack
Average relative Average relative velocityvelocity
δv∞
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
no Q⋅ω=Ω
1.5
Cml =0.12 + 0.18 0
Cm
l
2.00
0
0.5
(tilnærmet)
1.0
2.5 3.0
( )
m1
n
m1
22
n
c4Q
D
c4
dDQ
⋅Π
⋅=
⇓
⋅−⋅Π
=
Diameter of the runner
Ω
Ω
Height of the guide vanesand runner diameter
0.4
0.3300 400
ns
B /D0
d/D
d/D
, B
/D0
500 700600 800 900
0.5
0.6
0.7
45n
s HPnn ⋅=
Gap between hub and ring and the runner blades
Gap between the blade and hub
Gap between the blade and ring
Spalteåpning x =1000s/D
Virk
ning
sgra
d
00.80
0.85
0.90
1
s = x 10 d-3
2 3 4 5 6
Effic
ienc
y
Gap
Runaway speed
ϕ2
ϕ3
ϕ1
ϕ6
02
2.2
2.4
2.6
0.5 1.0 2.0 3.0σ
ϕ5
ϕ4
kavitasjonskoeffisient
Rus
ning
stal
l/nor
mal
turta
ll
Voit h
Cavitation coefficient
Run
away
spee
d
HH10 S−
=σ
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 =⋅=⋅ω=Ω
sm7,171682,92Hg2 =⋅⋅=⋅⋅
srad1,13
602125
602n
=Π⋅⋅
=Π⋅⋅
=ω
1m74,0s
m7,17s
rad1,13
Hg2−==
⋅⋅ω
=ω
2
3
nm78,6
sm7,17
sm120
Hg2QQ ==⋅⋅
=
Speed number:
Diameter, D:
467,018,012,01 =Ω⋅+= omc
mc
QD
m
n 3,4467,0
478,64
1
=⋅Π
⋅=
⋅Π
⋅=
Diameter, d:
59016
22826125 4545 =⋅=⋅=
mHp
rpmHPnnn
s
0.4
0.3300 400
ns
B /D0
d/D
d/D
, B
/D0
500 700600 800 900
0.5
0.6
0.7
m9,145,0Dd45,0Dd
=⋅=⇒=
Height, B:
0.4
0.3300 400
ns
B /D0
d/D
d/D
, B
/D0
500 700600 800 900
0.5
0.6
0.7
m76,141,0DB41,0DB
OO =⋅=⇒=
Number of vanes, z:
95,0tl=
5z =
Num
ber o
f bla
des
z