turbo m aquinas presentacion

8/18/2019 Turbo m Aquinas presentacion

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Design Analysis of Parts of Francis

Turbine

P M V Subbarao

Professor

Mechanical Engineering Department

Provision of Features to Blend some

Reaction into Impulse…


2/35

p

Spiral Casing

• Spiral Casing : The fluid enters from the penstock to a spiralcasing which completely surrounds the runner.

• This casing is known as scroll casing or volute.

• The cross-sectional area of this casing decreases uniformly alongthe circumference to keep the fluid velocity constant in

magnitude along its path towards the stay vane/guide vane.


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Design of Spiral Casing

Rcasing

Risv

d penstock

Q

How to select !


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Spiral Casing for "# $% &ertical 'rancis Tur(ine


5/35

Design of Spiral Casing

Rcasing

Risv

d penstock

Q Select a suita(le value of

discharge per unit) Q

*

+ penstock penstock d V Q

π =

,ut maimum allowa(le value is m/s

Maximum allowable head loss in Penstock =2 to 4% o

available head


6/35

0t any angle θ 1 the radius of casing is)

penstock isv d R Rπ κθ *

casing +=

0 full spiral is generally recommended for high head "m1 semi-spiral

is recommended for low head 2 #m!

π θ θ *

QQ =

3n general κ 4.1however corrected

using C'D.


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'low Distri(ution 0nalysis of Casing

Stay vanes or 5uide vanes


8/35

Static 6ressure Distri(ution in Casing.


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$ega Civil %orks for $echanical 6ower 5eneration


10/35

6arts of 0 'rancis Tur(ine


11/35

5eometrical Description of 0 'rancis Tur(ine 6arts


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Stay &anes 7 5uide &anes

• The (asic 6urpose of the stay vanes 7 guide vanes is to converta part of pressure energy of the fluid at its entrance to the kineticenergy and then to direct the fluid on to the runner (lades at theangle appropriate to the design.

• $oreover1 the guide vanes are pivoted and can (e turned (y asuita(le governing mechanism to regulate the flow while theload changes.

• The guide vanes are also known as wicket gates.

• The guide vanes impart a tangential velocity and hence an

angular momentum to the water (efore its entry to the runner.• The guide vanes are constructed using an optimal aerofoil shape1

in order to optimi8e off-design performance.


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Design of 5uide %heel 9Stator:) ;ow Specific Speed


14/35

Design of 5uide %heel 9Stator:) High Specific Speed

−−−−

⋅=Ω Qω

g" */ω ω =−−

g" QQ */=−−


15/35

Design of the 5uide &anes

Diameter of guide vane shaft

1,0

1,1

1,2

1,3

1,4

1,5

1,6

1,7

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6

Speed number

D i a m e t e r R a t i o

D 0 / D 1

D

D*


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Design of the Details of Stay 7 5uide &ane %heels

• The inlet angle can (e calculated (y

assuming a free vorte from the

flow coming from the spiral casing

$taVaneinlet $taVaneinlet w&uideVaneinlet &uideVaneinlet w ' V ' V ⋅=⋅

gi&uideVaneinlet

&uideVaneinlet

( #

QV

⋅⋅

=

π

r inlet ui!e "ane

r inlet #tay "ane

Bgi Bsi

Theory of >elatively free %hirling flow)

g" k V wgo guideVaneexit w * =

"+.to


17/35

6ressure drop versus discharge

6ressure drop versus 'low >ate


18/35

5lo(al Symmetric 'low Domain through Statinary

&anes


19/35

?perational Configurations of 5uide &anes


20/35

The correlation (etween the tur(ine

discharge and the guide vane opening angle.


21/35

6ressure drop versus guide vane angle


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( ).."++ * +Ω⋅+Ω⋅−⋅= go

α

α ο

−−−−

⋅=Ω Qω

g" */ω ω =−−

g" QQ */=−−

How to choose the guide vane maimum angle α

at full

load !


23/35


;evel of ?verlapping of the guide vanes


24/35

Design of Guide Vanes

ui!e $ane at Design

Position % 12&21'

ui!e $ane at close! (osition

ui!e $ane at )a*& o(enPosition % 18'

&

4 . # t o " / @

o f # g o

; ) l e n g

t h o f v a

n e


25/35

Guide vanesGuide vanesGuide vanesGuide vanesGuide vanesGuide vanes

+unner inlet

(Φ 0.870m)

ui!e $ane outlet for !esign(Φ 0.913m)

Closed

Positiona!. "penin#

Position


26/35

Design of the 5uide &ane ?utlet 0ngle

• The outlet angle can (e calculated (y assuming a free vorte from

the flow in the gap (etween the runner and the guide vanes

n

'iwgi

n

gowgo ' V ' V ⋅=⋅

g g

o ( #

QV

⋅⋅= π

r ri

Dg0

Bg0

g" k V o o *=

.Ato".= ok


27/35


How to choose the num(er of vanes

• The num(er of guide vanes has to (e different

from the num(er of runner vanes.

)ntege' *

*

Vanes Runne'

Vanes&uide≠


28/35

R a d i a l v i e w

runner guide vanes and stay vanes

R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w


R a d i a l v i e w

runner guide vanes and stay vanesR a d i a l v i e w


$ater %rom

spiral &asin#

$ater

parti&le


29/35

Bum(er of guide vanes

16

18

20

22

24

26

28

30

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6

Speed 'umber

'

u m b e r o % ( u i d e ) a n e s

g" */ω ω =−−


30/35

Bum(er of 5uide &anes

Bs

Dge1mm

4 * + A * *+

2* 2*# *# -+ + -A A - - *# *#


31/35

The >unner


32/35

$ean &elocity triangles 0cross >unner

ω ' ,

, ,

'

'i'e

=

<


33/35

&elocity triangles

' 'i

' 'e

, 'iV wi

V 'iV i

V ai

, 'eV we

V 'eV e

V ae

β i

α i

β eα e

ω ' ,

, ,

'

'i'e

=

<


34/35

The transposition of the profiles for all the streamlines


35/35

, b V wi

V ai

V iV 'i

, b

V wi

V ai V i

V 'i

Vwi, b

V ai

V iV 'i

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