Turbine Air(Francis).pptx

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A.

Agung Putu Susastriawan

Jurusan Teknik Mesin – IST. AKPRIND

TURBINE FRANCIS



•The static pressure at the runner exit may be less than the atmospheric

pressure and as such, water fills all the passages of the runner blades.

•The change in pressure while water is gliding over the blades is called

„reaction pressure‟ and is partly responsible for the rotation of the

runner.

•A Francis turbine is suitable for medium heads 45 to 400 m) and

requires a relatively large quantity of water.

•It is a reaction turbine developed by an English

born American Engineer, Sir J.B. Francis.

• The water enters the turbine through the outer

periphery of the runner in the radial direction and

leaves the runner in the axial direction, and hence

it is called „mixed flow turbine‟.

•It is a reaction turbine and therefore only a part of

the available head is converted into the velocity

head before water enters the runner.•The pressure head goes on decreasing as the water

flows over the runner blades.



TURBINE FRANCIS



Komponen Turbin Francis

D2



Spiral Casing

The spiral casing surrounds the runner completely.

Its area of cross section decreases gradually around the

circumference.

Water from the penstock pipes enters the spiral casing and

is distributed uniformly to the guide blades placed on the

periphery of a circle.

The casing should be strong enough to withstand the high

pressure.



Q

0

d

0

R

0

θ

R

i

2

10

4

d vQ i

gH K v vii 2

Flow rate air per sekon

dengan:

K

v1

= 0.15– 0.2

Bebanding terbalik dgn

specifik Speed)

Jumlah Air:

1

2d R R io

R

o

terhadapθ

0

2QQ

v

1

= Kecepatan Air pada Penstock



Guide Blades

Diameter guide blades

trailing edge:

N

gH K

N

u D uo

26060 0

0

K

u0

= 0.6-1.34~ Ns

Ketinggian Guides Blades:

00

0

mv D

Q B

dengan:

V

mo

=kecepatan radial pada exit

gH K v vmm 200

K

vm0

= 0.15-0.35~ Ns



Z0 8 10 12 14 16 18 20 24

Ns ≤ 200 D0 < 250 250-400 400-600 600-800 800-1000 1000-1250 1250-1700 >1700

Ns >200 <300 mm 300-450 450-750 750-1050 1050-1350 1350-1700 1700-2100 >2100

Jagdish Lal “Hidraulic Machines”

Practical Value Antara Jumlah Guides Blades Z

0

) dengan D

0



D1

D2

Inlet diameter:

N gH K

N u D u

26060 11

1

Outlet diameter:

0

2

4

mv

Q D

Francis Runner



Runner

The runners change the direction and magnitude of the fluid velocity

This process absorb the momentum from the fluid.



Draft Tube

1. to regain the lost static head due to higher level installation of the turbine

2. helps to recover part of the kinetic energy that otherwise may be lost at the

turbine outlet.

H2

datum

g

V H

g

V H

H g

V H

g

V H f

h

22

22

2

3

3

2

1

1

2

3

3

2

1

1

H3

H1

Efisiensi Francis Sistem:



Kaplan Turbine



Kaplan Turbine: axial flow turbine



D0

Diemeter Guide Wheel D

0

)

N

gH k D

ug

260

0

k

ug

1.3 to 2.25 : Higher values for high specific speeds



Kaplan Runner Propeller Runner)

Drunner

Dhub

N H N D srunner

60

602.179.05.84

runner

s

hub D N

D

0951.025.0

486.0

827.39

H N s engan statistical studies dari F. Schweiger and J.

Gregory, Kecepatan Specifik untuk Turbin Kaplan:

Power Yang Dihasilkan

oleh Kaplan Runner:

blade A

reribladebladetotal V V U md n P



Whirl Chamber

Guide Vanes

Whirl Chamber

a

b

Ruang/space antara guide wheel outlet dan Kaplan runner

a=0.13 D

runner

b=0.16 D

runner

.

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Turbine Air(Francis).pptx

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