Perancangan Turbin Pelton

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Transcript of Perancangan Turbin Pelton

Design of Pelton turbines

When to use a Pelton turbine

Energy conversion in a Pelton turbineOutlet Outlet of the runner Inlet of Outlet of the runner the needle Inlet of the needle

c2 2

Main dimensions for the Pelton runner

The ideal Pelton runnerAbsolute velocity from nozzle:

c1 = 2 g H nCircumferential speed:

c1 =

c1 =1 2 g Hn

c1u 1 u1 = = 2 g Hn 2 2Euler`s turbine equation:

u 1 = 0.5

h = 2(u1 c1u u 2 c 2 u )c1u = 1 cu 2 = 0

h = 2 (u1 c1u u 2 c 2u ) = 2 (0,5 1.0 0,5 0) = 1

The real Pelton runner For a real Pelton runner there will always be losses. We will therefore set the hydraulic efficiency to:

h = 0.96The absolute velocity from the nozzle will be:

0.99 c1u < 0.995C1u can be set to 1,0 when dimensioning the turbine. This gives us:

h = 2(u1 c1u u 2 c 2 u )

n 0,96 u1 = = = 0,48 2 c1u 2 1,0

From continuity equation:

d Q = z c1u 4

2 s

ds =Where: Z Q C1u = = = number of nozzles flow rate 2 g Hn

4Q z c1u

The size of the bucket and number of nozzlesB 3.1 > 3.4 dsRules of thumb: B = 3,1 ds B = 3,2 ds B = 3,3 ds B > 3,3 ds 1 nozzle 2 nozzles 4-5 nozzles 6 nozzles

Number of bucketsz 17empirical

Number of buckets

Runner diameterRules of thumb: D = 10 ds D = 15 ds D < 9,5 ds D > 15 ds Hn < 500 m Hn = 1300 m

must be avoided because water will be lost is for very high head Pelton

Speed number = Qz2 2 ds ds Q= c1u = 4 4

c1u = 1,0 u1 = 0,5

2 g Hn 2 u1 1 = = = = 2 g Hn D 2 g Hn D 2 g Hn D2 z 1 ds = Q z = D 4

ds = D

z 4

For the diameter: and one nozzle:

D = 10 ds z=1

ds = D

z 1 1 = = 0,09 4 10 4

The maximum speed number for a Pelton turbine with one nozzle is = 0,09

For the diameter: and six nozzle:

D = 10 ds z=6

ds = D

z 1 6 = = 0,22 4 10 4

The maximum speed number for a Pelton turbine today is = 0,22

Dimensioning of a Pelton turbine1. The flow rate and head are given*H = 1130 m *Q = 28,5 m3/s *P = 288 MW

2.

Choose reduced valuesc1u = 1 u1 = 0,48 c1u = 149 m/s u1 = 71 m/s

3.

Choose the number of nozzlesz=5

4.

Calculate ds from continuity for one nozzleds = 4Q = 0,22 m z c1u

5.

Choose the bucket width B = 3,3 ds= 0,73 m

6.

Find the diameter by interpolationD = 0,005 H n + 8 = 13,65 ds D = 13,65 d s = 3,0 m

D/ds15

10 400 1400

Hn [m]

7.

Calculate the speed:u1 = D 2 n D = 2 60 2

u 60 n= 1 = 452 rpm D

8.

Choose the number of poles on the generator: The speed of the runner is given by the generator and the net frequency:n= 3000 [rpm] Zp

where Zp=number of poles on the generator The number of poles will be:Zp = 3000 = 6,64 = 7 n

9.

Recalculate the speed:3000 = 428,6 [rpm] Zp

n=

10.

Recalculate the diameter:u1 = D 2 n D u 60 = D= 1 = 3,16 m 2 60 2 n

11.

Choose the number of buckets z = 22

12.

Diameter of the turbine housing (for vertical turbines)

D Hou sin g = D + K B = 9,4 mK9

8 1 4 6

z

13.

Calculate the height from the runner to the water level at the outlet (for vertical turbines)

Height 3.5 B D = 3,1 m

GE Hydro

Jostedal, Sogn og Fjordane

GE Hydro

Jostedal, Sogn og Fjordane

ExampleKhimti Power Plant1. The flow rate and head are given*H = 660 m *Q = 2,15 m3/s *P = 12 MW

2. Choose reduced valuesc1u = 1 u1 = 0,48 c1u = 114 m/s u1 = 54,6 m/s

3. Choose the number of nozzlesz=1

ExampleKhimti Power Plant4. Calculate ds from continuity for one nozzleds = 4Q = 0,15 m z c1u

5. Choose the bucket widthB = 3,2 ds= 0, 5 m

6. Find the diameter by interpolationD = 0,005 H n + 8 = 11,3 ds D = 11,3 d s = 1,7 mD/ds15

10 400 1400

Hn [m]

7. Calculate the speed:D 2 n D u1 = = 2 60 2 n= u1 60 = 613 rpm D

8. Choose the number of poles on the generator: The speed of the runner is given by the generator and the net frequency:3000 n= [rpm] Zp

where Zp=number of poles on the generator The number of poles will be:

3000 Zp = = 4,9 = 5 n

9. Recalculate the speed:

3000 n= = 600 [rpm] Zp10. Recalculate the diameter:

u1 =

D 2 n D = 2 60 2

D=

u1 60 = 1,74 m n

11. Choose the number of buckets z = 22