/15/1/

2008 )1-13(

. ..

-

"

.

:.

.

(Erosion)

.

)12%(

"[1] .

)Krzyzanowski 1971-

1974-1978([2] [3] [4]

:

)Erosion(

)0.8C(C

.

1

/15/1/

2008 )1-13(

)Yeoh & Young 1984([5]

. :

-1)Super-cooled

steam(

15%

.

-2

)10o (

-3

.

)Nardin, 1999([6]

.

:

-1)12% Cr(.

-2

)Ti-6-V.(

-3).(

P=100

Mbar T=30°C

)(

.

.

[7].

(a)

)b()1(

)c(

)c(

[8].

:

(Pr)(Tr)

)r(Kelvin

Helmoholtz [1] :

rrs TrR

2exp)T(PP

fr ············· (1)

(Critical

droplet size)

2

/15/1/

2008 )1-13(

:

sRTr

gfcrit ln

2

························ (2)

:

r

r*TTT crit

Sr ···················· (3)

) Knudson number([1] :

Knrg

2 ························ (4)

:-

p

RT5.1 sgg

···················· (5)

(0.01<Kn<4.5)

:

1k

Kn*k

Pr5.1

821

1*

r

g

g

r············ (6)

(6)

)k=1.3Prg=1.2 (

:

g

gr *59.1r

· ··············· (7)

:

grr2 TTr4Q ··················· (8)

-

(wr)

[1]:

2rg

2 w2

1rCdFd ························ (9)

Cd

:

3

/15/1/

2008 )1-13(

rgg

g

r w.*35.1r

24

Kn7.21

1

Re

24Cd (10)

g

r2

g

.35.1r

wr12Fd

······················ (11)

[2]:

dwWe

2

rg ·················· (12)

)

(

)20 (.

(Trailing

Edge)

(Splashing) .

)2.(

.

.

[1]:

S*Kn*7.21

1

*d

*18ClnCCCln*CC

f2

g**

..(13)

Droplet Growth Theory

(Nucleation Theory)

(Ql) )dr/dt (

:

u

s

h

T

rr

rrlnr59.1rrrr59.1

2

rr

fgf

g

crit1

critcritcrit1crit

2

1

2

······················· (14)

(Erosion)

.

(0.8C)C

. )3 (

AB

4

/15/1/

2008 )1-13(

AC

BC

AD

CD

.

(J.K.rzyznowzki) [4]

:

222 )(2)()(1

118.0C

SASASAC

······ (15)

:

(16)

:

f

N*N*ffmax a

w*21w*a*P ····· (17)

)af (.

Heymann) (

:

5

N

e

aem 2550

w

N

UU

······················· (18)

(Ne)

(18Cr-8Ni)Uem

t

5

N* Y

Y*25.0exp

w

2550

Ua

Ne*Y ··· (19)

][7],[6

.

)19(:

t

69.1392.4

N*a

e

Y

Y25.0exp

d

10

w

2550

U

NY

·················· (20)

6 .

)8.33 (

(300°C)

)0.06bar (100 %

)(

)(1)(

1

111

b

bbN SinuC

SinCCSinuW

5

/15/1/

2008 )1-13(

)1.(

.

-1 :

)0.978-0.962(

)4.(

-2

)S(:

)0.0442m ()5 (

)13 (

(S) )S (

.

"

.

.

)12 (

)2 (

(200 m)

.

3 -:

)6 (

.

)7(

)CA3 (

CD

.)7 (

.

)8 (

)650Mpa ()17 (

.

)9 (

)10 (

"

6

/15/1/

2008 )1-13(

)11 (

)Stellite strip.(

.

4 -

)12 (

) (

) ( )13 (

) (

)14 (

)11.(

:

-1

.

-2

.

-3

.

-4

.

-5

."

-6

.

1-Moore,.M.J, Sievrding .C.H, "Two Phase

Steam Flow in Turbine and separator",

Mc-Graw Hill,1976.

2-Krzyzanowski and et al,"Semi-

Empirical of Erosion Threat in

Modern Steam Turbine",ASME

Journal of Power for Engineering,Vol

93,No 1,1971.

7

/15/1/

2008 )1-13(

3-Krzyzanowski, "The Correlation Between

Droplet Stream Structure and Steam

Turbine Blading Erosion" ,ASME Journal

of Power for Engineering,Vol 96,No

4,1974.

4- Krzyzanowski and Szperie, "The

Influence of Droplet Size On The turbine

Blading Erosion Hazard", ASME Journal

of Power for Engineering, Vol 100,No

4,1978.

5-Yeoh ,C. C, and Young, J. B., "Non

Equilibrium Through Flow Analysis of

Low-Pressure Wet Steam Turbine",

ASME Journal of Power for Engineering,

Vol 106, October 1989

6-Nardin, p., "Erosion Study of Final stage

Blading of Low Pressure steam Turbine",

Journal of Applied Surface Science,1999.

7-"

"

1988.

8-Jaffe, R. I, Corrosion Fatigue of Steam

Turbine Blade" Work Shop, Palo Alto,

California, Sept, 21-24, 1980

8

/15/1/

2008 )1-13(

)1 (

)2(

)1 (

)2 (

)(

)C(

) x(

33 10mKg

1 8.33 300 - 312

2 4.66 245 - 489.4

3 2.44 188 - 878.4

4 1.6 125 - 1127.6

5 0.45 79.24 0.986 3527.414

6 0.18 57.8 0.956 8073.42

7 0.06 36.16 0.926 21982.314

( m) 35 100 200 300 400

)

=300/(

2.252 7.887 16.82 25.80 34.8

)

=340/(

2.954 10.21 21.69 33.24 44.8

Full load

Entropy S

Expansion Line

Enthalpy h

Full load

Area of Wilson Lines

20% partial load

partial load

Reheat turbines

150°C

90°C 0.7 bar

150°C 48 bar

30°C 0.05 bar

9

/15/1/

2008 )1-13(

)3 ([8]

)4 (

)5 ()S(

)6 (

h

s

0.00 0.03 0.06 0.09 0.12Streamwise distance (m)

0

20

40

60

80

Dro

p ve

loci

ty (

m/s

)

steam velosity=270 m/s

d=35

d=100

d=200

d=300

d=400

0.00 0.03 0.06 0.09 0.12Streamwise distance (m)

0

20

40

60

80

Dro

p ve

loci

ty (

m/s

)

steam velocity=300 (m/s)

d=35

d=100

d=200

d=300

d=400

30

340

0 10 20 30 40 50 60Blade Length(cm)

60

80

100

120

Dro

plet

vel

ocity

(m/s

)

Steam velocity=300(m/s)

Steam velocity=350(m/s)

Steam velocity =400(m/s)

10

/15/1/

2008 )1-13(

)9 (

)11 (

0 10 20 30 40 50 60 70Blade Length (cm)

200

300

Nor

mal

com

pone

nt o

f im

pact

vel

ocity

(m/s

)

Steam velocuty= 300(m/ s)

Steam velocity=350(m/ s)

Steam velocity=400(m/ s)

)7 (

0 10 20 30 40 50 60Blade Length (cm)

200

300

400

500

600

700

Impa

ct p

ress

ure(

MPa

)Steam velocity=300 m/s

Steam velocity=350 m/s

Steam velocity=400 m/s

)8 (

0 2 4 6 8 10 12 14 16Time(year)

0E+0

2E-4

4E-4

Mea

n er

osio

n de

pth(

m)

Diameter of droplet=80E(-6)Impact velocity=35(m/s)

Impact velocity=40(m/s)

Impact velocity=50(m/s)

Impact velocity=60(m/s)

Impact velocity=70(m/s)

0.0 0.1 0.2 0.3 0.4 0.5 0.6Blade Height (m)

1E-4

2E-4

3E-4

4E-4

Mea

n er

osio

n de

pth(

m)

Steam velocity=350(m/s)

Steam velocity=300(m/s)

Steam velocity=400(m/s)

)10 (

0.01 0.01 0.02Distance (e)

50

100

150

Dro

plet

vel

ocity

(m/s

)

Steam velocity=350(m/s)

Steam velocity=300(m/s)

Steam velocity=400(m/s)

)12 ()(

11

/15/1/

2008 )1-13(

0.01 0.01 0.02the distance (e)

200

300

400

Nor

mal

com

pone

nt o

f th

e im

pact

vel

ocit

y(m

/s)

Steam velocity =300 (m/ s)

Steam velocity = 350 (m/ s)

Steam velocity = 400 (m/ s)

)13 (

)(

0.005 0.010 0.015Distance (e) m

200

400

600

800

Impa

ct p

ress

ure(

Mpa

)

Steam velocity=300 (m/s)

Steam velocity =350(m/s)

Steam velocity =400(m/s)

)14 ()(

12

/15/1/

2008 )1-13(

STUDY THE EFFECT OF ERROSION ON THE BREAKAGE OF

STEAM TURBINE BLADE AT BAIJI POWER STATION

Dr. Mohanned Abdu-Alfattah Dr. Tahseen Taha Othman Dr. Omer Khlil Ahmed Assistant Prof. Assistant Prof. Lecturer Mech. Eng. Dept. Mech. Eng. Dept. Al-Anbar University Kirkuk University Technical College- Kirkuk

ABSTRACT

The last stage endured on obvious erosion especially the front and the end of the

blade. The erosion caused the appearance some cracks in this place. These remarks

coincided with the theoretic al results, which were acquired according to the condition of

the turbine of station which showed that the droplet, which collided with the blade ends,

caused high pressure on the surface of the blade and caused the occurrence of the

corrosion. The danger of the erosion unavoidable due to its relationship with tae station

efficiency and the only to avoid that is the use of the blade made of erosion resistance

ingots.

KEY WORDS: Steam Turbine Blade, Erosion, Humidify Steam

13

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