toda-1973-on the particle velocities in solid-.pdf

7
7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 1/7 tensor and of the stress tensor definedby Eq. 3) [g/cm .sec2], [1/sec] Literature Cited 1) Foster, R. D. and J. G. Slattery: Appl. Sci. Res., A12, 213  1962) 2) H ill, R. and G. Power: Quat. J. M ech. Appl. M ath., 9, 313  1956) 3 Hopke, S. W . andJ. C. Slattery: AIChE Journal, 16, 224 1970 4 Johnson, M . W .Jr. : Trans.Soc.Rheol, 5, 9 1961 .5) Kato, H ., N. Tachibana and K. Oikaw a: Trans. JSM E, 38, 821 1972 6 Turian, R. M. : AIChEJournal, 13, 1000 1967 7) W asserman, M . L. andJ. G. Slattery: AIChE Journal, 10, 383  1964) 8 Yoshioka, N. and K. Adachi: J. Chem. Eng. Japan, 4, 217  1971) 9 Yoshioka, N. and K. Adachi: J. Chem. Eng. Japan, 4, 221  1971) 10) Yoshioka, N., K. Adachi and H . Ishim ura: Kagaku Kogaku, 35, 1144 1971 Yoshioka, N. and R. N akamur a: Kagaku Kogaku, 29, 791  1965) 12 Ziegenhagen, A .: A ppl. Sci. Res., A14, 43 1964 ON THE PARTICLE VELOCITIES IN SOLID-LIQUID TWO-PHASE FLOW THROUGH STRAIGHT PIPES AND BENDS* Masayuki TODA, Toichi ISHIKAWA, Shozabvro SAITO and Siro MAEDA Department of Chemical Engineering, Tohoku University, Sendai Japan The m ean particle velocities in horizontal pipe, vertical pipe and pipe bends madeof transparent polyacrylate pipe 30.2 m m in inside diameter were investigated experimen- tally. The radii of curvature of the bends w ere 12, 24 and 48 cm , The solid particles used were glass beads which had a meanparticle diameter of 0.189 cm and a density of 2.5 g/cm3.Radioactive particles wereintroduced as tracer and the particle velocities were determined by scintillation probes. The particle velocities in both the straight pipes and the bends are distributed in wide ranges, because the flow path of each particle in pipe is different. The particle velocity in vertical pipe is greater than that in horizontal pipe. The particle velocities in vertical bends with horizontal approach flow are in general smaller than those in the other bends. Theeffect of the radius of curvature on the particle velocity comesto be larger whenthe meanflow rate of slurry increases. Introduction In studying hydraulic transportation of solid mate- rial in a pipe, it is necessary to know the velocities of the solids and the fluids at various locations along the Pipe- The velocity distribution of the fluid in two-phase flow has been studied by many authors1 2*4 5 6). However, the velocities of the solid particles have not been examined to a sufficient extent as yet, mainly because of the difficulties in their measurement. Only a few studies3 6) have been madeof the velocity of a single particle in fluid flow. In the present study, the velocities of the particles in horizont l pipe vertic l pipe nd bends with v rious radii of curvature weremeasured. 1 Experimental Apparatus and Procedure Theexperimental apparatus is shownschematically in Fig. 1. A transparent polyacrylate pipe of 30.2 mm inside diameter wasused. Three kinds of right-angle bends7} were used, of which the radii of curvature w ere 12, 24 and 48 cm . The solid particles used in this experiment were -glass beads, whose mean particle diameter and density w ere 0.189 cm and 2.5 g/cm3, respectively. The meanflow rate of the two-phase flow and the concentration of supplied particles were evaluated by measuring the flow rate at the outlet directly. To deter-  Received on September 7, 1972 Presented at the Local Meeting of The Soc. of Chem. Engrs., Japan Akita, Sept. 1971) •§980å‘ä‘å‰ÔŠªŽšÂ—t “Œ–k‘åŠwHŠw”‰»ŠwHŠw‰È•@“s“c ¹”V 1 40 JOURNALOF CHEMICAL ENGINEERING O FJ A PA N

Upload: muhammad-adnan-laghari

Post on 13-Apr-2018

216 views

Category:

Documents


0 download

TRANSCRIPT

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 1/7

te n so r a n d o f th e s tre ss te n so r d e fin e d b y E q . 3 )

[ g / c m .s e c 2 ] , [ 1 / s e c ]

L it e ra t u re C i t e d

1 ) F o s t e r , R . D . a n d J . G . S l a t t e r y : A p p l . S c i . R e s . , A 1 2 , 2 1 3

  1 9 6 2 )

2 ) H i l l , R . a n d G . P o w e r : Q u a t . J . M ec h . A p p l . M at h . , 9 , 3 1 3

  1 9 5 6 )

3 H o p k e , S . W . a n d J . C . S l a t t e r y : A I C h E J o u r n a l , 1 6 , 2 2 4 1 9 7 0

4 J o h n s o n , M . W . J r . : T r a n s . S o c . R h e o l , 5 , 9 1 9 6 1

. 5 ) K a t o , H ., N . T a c h i b a n a a n d K . O i k a w a : T r a n s . J S M E , 3 8 ,

8 2 1 1 9 7 2

6 T u r i a n , R . M . : A IC h E J o u r n a l , 1 3 , 1 0 0 0 1 9 6 7

7 ) W a s s e r m a n , M . L . a n d J . G . S l a t t e r y : A I C h E J o u r n a l , 1 0 , 3 8 3

  1 9 6 4 )

8

Y o s h i o k a , N .

a n d K. A d a c h i :

J. C h e m .

E n g .

J a p a n , 4 , 2 1 7

  1 9 7 1 )

9

Y o s h i o k a ,

N.

a n d

K. A d a c h i :

J. C h e m . E n g . Japan, 4 , 2 2 1

  1 9 7 1 )

1 0 ) Y o s h i o k a , N . , K . A d a c h i a n d H . I s h i m u r a : K a g a k u K o g a k u , 3 5 ,

1 1 4 4 1 9 7 1

Y o s h i o k a , N . a n d R. Nakamura:

K a g a k u

Kogaku, 2 9 , 7 9 1

  1 9 6 5 )

1 2 Z i e g e n h a g e n , A .: A p p l . S c i . R e s . , A 1 4 , 4 3 1 9 6 4

O N

T H E

P A R T I C L E V E L O C I T I E S I N S O L I D - L I Q U I D

T W O -P H A S E F L O W T H R O U G H S T R A IG H T P IP E S

A N D B E N D S*

M as a y uk i T O DA, T o ich i ISH IK AW A,

Sh o z a b v ro SAIT O a n d Siro M AE DA

D e p a r t m e n t o f C h e m i c a l E n g i n e e r i n g , T o h o k u U n i v e r s i t y ,

S e n d a i J a p a n

T h e m e a n p a r t i c l e v e l o c i t i e s i n h o r i z o n t a l p i p e , v e r t i c a l p i p e a n d p i p e b e n d s m a d e o f

t r a n s p a r e n t p o l y a c r y l a t e p i p e 3 0 . 2 m m i n i n s i d e d i a m e t e r w e r e i n v e s t i g a t e d e x p e r i m e n -

t a l l y . T h e r a d i i o f c u r v a t u r e o f t h e b e n d s w e r e 1 2 , 2 4 a n d 4 8 c m , T h e s o l i d p a r t i c l e s u s e d

w e re gla ss b e a d s w hich h a d a m e a n p a r tic le d ia m e te r o f 0 .1 8 9 cm a n d a d e n s ity o f 2 .5

g/cm 3 . Ra dio ac tiv e p ar t ic le s w e re i n tro duce d a s tr a ce r a nd th e p ar tic le v elo ci tie s w e r e

d e t e r m i n e d b y s c i n ti l l a t i o n p r o b e s .

T h e p a rt icle v e lo c itie s in b o th th e s tra igh t p ip e s a n d th e b e n d s a re d is tr ib ute d in

w i d e r a n g e s , b e c a u s e t h e f l o w p a t h o f e a c h p a r t i c l e i n p i p e i s d i f f e r e n t . T h e p a r t i c l e

v e l o c i t y i n v e r t i c a l p i p e i s g r e a t e r t h a n t h a t i n h o r i z o n t a l p i p e . T h e p a r t i c l e v e l o c i t i e s i n

v e rtica l b e n d s w ith h o riz o n ta l a p p ro a ch flo w a re in ge n e ra l sm a lle r th a n th o se in th e

o th e r b e n ds . T he e f fe c t o f th e r a d ius o f cu rv a tu re o n th e p a rt ic le v e lo ci ty c o m es to b e

la rge r w he n th e m ea n flo w ra te o f s lurry in cr e as e s.

I n t r o d u ct i o n

I n s t u d y i n g h y d r a u l i c t r a n s p o r t a t i o n o f s o l i d m a t e -

r i a l i n a p i p e , i t i s n e c e s s a r y t o k n o w t h e v e l o c i t i e s o f

t h e s o li d s a n d t h e f l u i d s a t v a r i o u s l o c a t i o n s a l o n g t h e

P i p e -

T h e v e l o c i t y d i s t r i b u t i o n o f t h e f l u i d i n t w o - p h a s e

f l o w

h a s

b e e n s t u d i e d b y m a ny a ut h o r s 1 2 *4 5 6) .

H o w e v e r , t h e v e l o c i t i e s o f t h e s o l i d p a r t i c l e s h a v e n o t

b ee n ex am in e d to a s ufficien t e x te n t a s y e t, m a in ly

b e c a u s e o f t h e d i f f i c u l t i e s i n t h e i r m e a s u r e m e n t . O n l y a

f e w s t u d i e s 3 6 ) h a v e b e e n m a d e o f t h e v e l o c i t y o f a

s i n g l e p a r t i c l e i n f l u i d f l o w .

I n t h e p r e s e n t s t u d y , t h e v e l o c i t i e s o f t h e p a r t i c l e s

i n h o r i z o n t l p i p e v e r t i c l p i p e n d b e n d s w i t h v r i o u s

r a d ii o f c u r v a t u r e w e r e m e a s u r e d .

1 E x p e r im en ta l Ap p a r a tu s a n d Pro ce d ure

T h e e x pe rim e nta l a pp ar atus is s ho w ns ch e ma tic ally

i n F i g . 1 . A t r a n s p a r e n t p o l y a c r y l a t e p i p e o f 3 0 . 2 m m

i n s i d e d i a m e te r w a s u s e d . T h r e e k i n d s o f r i g h t - a n g l e

b e n d s 7 } w e r e u s e d , o f w h i c h t h e r a d i i o f c u r v a t u r e

w e r e 1 2 , 2 4 a n d 4 8 c m . T h e s o l i d p a r t i c l e s u s e d i n t h i s

e x p e r i m e n t were

- g l a s s b e a d s ,

w h o s e mean particle

d i a m e t e r a n d d e n s i t y w e r e 0 . 1 8 9 c m a n d 2 . 5 g / c m 3 ,

r e s p e c t i v e l y .

T h e m e a n flo w ra te o f th e tw o-p h a s e f lo w a n d th e

c o n c e n tr a t i o n o f s u p p l i e d p a r t i c l e s w e r e e v a l u a t e d b y

m e a s u r i n g t h e f l o w r a t e a t t h e o u t l e t d i r e c t l y . T o d e t e r -

  Received on September 7, 1972

Presented at the Local Meeting of The Soc. of Chem. Engrs.,

Japan Akita, Sept. 1971)

•§980å‘ä‘å‰ÔŠªŽšÂ—t

“ Œ – k ‘ å Š w H Š w ” ‰ » Š w H Š w ‰ È • @ “ s “ c ¹ ” V

1 40

J O UR N ALO F C H E M IC AL E NGIN EE RING O FJ A PA N

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 2/7

F ig . 1 Schem atic d iag ram of experim en ta l appara tu s

f

/f

\ R

= 2 4 f t m 3

Jeff i ds« 0.189CcnO

1g /

I

P ss

2 . 5 C g / c m 3 3

J f f / ' 0 m = 0 .7 6à C m /s ea )

li J j)

\

m e= 5 . 0 1 ' C % 3

= a5  Eft J

å h1

y JI o

H o r i z o n ta l p ip e

mY' I o- Horizontal bend

dJ/J j I c^ V ertica l bend(H -V )

r

I à

V er t i c a l p i p e

J jJ à | 4

V e r t i c a l b en d( V - H )

y ^ ^ ^ /

j M e a n

v e l o c i t y o f s l u r r y

0 : 0. 5 1. 0 1 : 5 2 . 0

U s C m / s l

F i g . 2 C um u l a t i v e d i s t r i b u t i o n f u n c t i o n o f p a r t i c l e

v e l o c i t y ( R un N o . 1 4 )

i .0 |- ,-= i -I^> -T-^ -å ^ sp rt f^ ff0^ - ^ -+ n

R = 2 4 [ c r r o x s ^ J I S ^ t / *

d s = 0 J8 9c c m D /V

| j f - & Y à

Ps= 2.5 rg/cm ] / V -i/Y /

m= 2 . 6 7

C m / s e c

> P

/j // /*

m c= 3 . 8 3 C % D  

/

/ \ i > i /

I \ f l //

-O -i/ à

~ 0.5 -/ ~/ -fl ~/ ° Horizontal pipe

6

P y/l

©

-o H o r i z o n ta l b e n d

/ / / / I / < )

V e r t i c a l b e n d ( H -V )

/

V cr - ^ à à V er t i c a l p i p e

f

f

^ -dr A ^ V e r t i c al b e n d ( V - H )

/f >/ t O ^ I

/* | M e a n

v e l o c i t y o f s l u r r y

o\j£LooS^v+a*^ l_J I 1 u

1. 5

2 0 2 . 5

3. 0

3 . 5 4 . 0

U s C m / s ]

F i g . 3 C u m u la t i v e d i s t r i b u t i o n f u n c t i o n o f p a r t i c l e

v e l o c i ty (R u n N o. 2 2 )

  a* ~

  M W I ds= 0.I89lcto

  ff If />s= 2.5 cg/cra'3

  9/ V Dm» 1.03 Cm/seci)

 - 6? / ' mc= 0.81 C%3

** i/ » ' ° Horizontal P'Pe

  9/ ff I ° Horizontal bend

  AO -J-1 \ <> Vertical bend(H-V)

  yj If i à . Vertical pipe

  $6 j}i I æf Vertical bend(V-H)  J$-1$9 I MMn velocity of slurry

  0 5*5 *^ I.O 1.5 2.0

  Us Cm/s^

F i g . 4 C u m u l a t i v e d i s t r i b u t i o n f u n c t i o n o f p a r t i c l e

v e l o c i t y ( R u n N o . 2 3 )

1.0, 1 1 Jr^Y^^ '^^^^^

d s =

O .I 8 9 C c n O >S

I A S & Z r

Ps - 2. 5

C g / c m

/ ^ < T / /

0ro= 2 . 7 6

C m / s e e 3

/ / t / l '

mc= 0.37 C J / \jf//

 5 , ^ r. - / p : / M e a n v e l o c i t y o f s l u r r y

# /// o

H o r i z o n t a l p ip e

/ yV> y | -o- Horizontal bend

y

A/ jM

  V e r t i c a l b e n d ( H - V )

> >

y ^ ^

I

à

V e r t i c a l p i p e

» ^ t

I

4

V e r t i c a l b e n d ( V - H )

oL^i . f«^J   I L _ 1

0 2.0 2 . 5 3 . 0 3 . 5 4 . 0

F ig . 5 C um u la t i v e d i s t r i b u t i o n f u n c t i o n o f p a r t i c l e

v e l o c i t y (R u n N o . 2 4 )

3 . o D -

3 . 0 2

c c n o ' / _

d s=

0 . I 8 9 c c m 3 A /

p % - -

2. 5 C g / c m 3 ] / ~ %

mc[ ] / cf

® 0.31-0.53 / ft

o0 72 1 22 / /

2. o ->

1 .6 7 - 5 . 0 1 / f - 7 7 ^ ^

3 -OSN.o. /y

£ - /A

/ c/^~

1.0- /--p- C ___ L_

0

1. 0

2 . 0 3 . 0

U m C m / s D

F i g . 6 P a r t i c l e v e l o c i t y i n h o r i z o n t a l p i p e

m i n e t h e v e l o c i t i e s o f t h e p a r t i c l e s i n t w o - p h a s e f l o w ,

r a d i o a c t i v e p a r t i c l e s w e r e i n t r o d u c e d a s t r a c e r . I n t h e

s t r a i g h t p i p e s , tw o s c i n t i l l a t i o n p r o b e s w e r e p l a c e d t o

d e t e c t th e i n t e n s i ty o f ^ - r a y a t th e m e a s u r i n g s e c t i o n

s h o w n i n F i g . 1 , a t a d i s t a n c e o f a b o u t 0 . 6 m . I n t h i s

m e a s u ri n g r e g i o n , t h e p re s s u re d ro p w a s d e t e rm i n e d

along the direction offlow . It w as confirm ed that the

f l o w i n v o l v e d n o a c c e l e r a t i o n . O n t h e o t h e r h a n d , i n

t h e b e n d s t w o s c i n t i l l a t i o n p r o b e s w e r e p l a c e d a t t h e

i n l e t a n d t h e o u t l e t o f a b e n d . F o r m a k i n g t h e t r a c e r , a

sm all am ount of glass beads w hose diam eter w as very

s i m i l a r t o t h e a v e r a g e p a r t i c l e d ia m e te r w a s i r r a d ia t e d

w i t h f - r a y . T h e i r r a d i a t i o n w a s c a r r i e d o u t b y t h e

3 0 0 -M e V L i n a c o f T o h o k u U n i v e r s i t y f o r t h r e e h o u r s ,

a n d t h e h a l f - d e c a y t i m e w a s a b o u t t h r e e h o u r s . T h i s

w a s e n o u g h f o r t h e p u r p o s e o f t h e p r e se n t e x p e r i m e n t .

T h e p a r t i c l e v e l o c i t i e s w e r e d e t e r m i n e d b y d i v i d i n g

th e t r a j e c t o r y l e n g th b e tw e e n tw o s c i n t i l l a t i o n p r o b e s

b y

th e

r e s i d e n c e

t ime .

I n

t h i s c a s e , i t i s

n e c e s s a r y t o

k n o w th e t r a j e c to r y l e n g th o f p a r t i c l e s i n th e p i p e o r

b e n d . I n t h i s w o r k , i t w a s f o u n d f r o m p h o t o g r a p h i c

o b s e r v a t i o n t h a t t h e l o c i o f p a r t i c l e m o t i o n s w e r e c o m -

p a r a t i v e l y p a r a l l e l t o th e a x i s o f s t r a i g h t p i p e s o r b e n d s .

Th u s , t h e a c t u a l l e n g t h o f t h e t r a j e c t o ry f o r s t r a ig h t

p i p e w a s a s s u m e d t o b e r e p r e s e n t e d b y t h e l o n g i t u d i n a l

d i s t a n c e a l o n g t h e a x i s . I n t h e b e n d s , i t w a s d e f i n e d a s

t h e a x i a l l e n g t h f r o m t h e i n l e t t o t h e o u t l e t o f a b e n d .

A l t h o u g h t h i s d e f i n i t i o n i s n o t g rounded i n t h e o r y , i t

s e e m s a lmos t

correct

because t h e d i f f e r e n c e b e tw e e n

t h e d i s t a n c e m o v e d a l o n g t h e a x i s a n d t h a t a l o n g t h e

i n s i d e o r o u t s i d e w a l l o f a b e n d i s a t m o s t ± 1 2 % .

V O L . 6 N O . 2 1 9 7 3

1 4 1

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 3/7

T ab le 1 M e a n p a r t i c l e v e l o c i t y ( R = 1 2 c x n )

R u n N o . U m [ n a / g f ] m c [ v o l% ] 1 7 « i r [ m / s ] t f .M [ m / s ] . * 7 W i? [ m / s ] * 7 s f [ m / s ] * 7 S F H i? [ m / s ]

1

2 . 1 9 0

0 . 4 3 8   L902 L 6 4 5   L918

2 2 . 1 2 8

0 . 9 8 7

 

2.362 1 3 7 3

  2172

3 1 . 8 1 5

3 . 4 8 9   1.493 1 . 3 5 4   1 734

4 0 . 9 1

1 1 . 4 0 5  

0.627

0 . 4 6 4   0731

5 2 .7 4 0 0 . 4 56  

2.363

2 . 0 7 4   2490

6 2 . 7 1 3 0 . 7 4 9

 

2.243 1 . 8 4 8

  2212

7

2 . 5 7 2

2 . 8 7 0

 

2.030

1 .65 7

  2340

8 0 . 9 1 5 0 . 4 7 1

 

0.887

0 . 5 8 9

  0876

9

1 . 0 6 6

3 . 3 2 4   0.802 0 . 4 8 3

  1 092

1 0 1 . 7 9 8   9 9 2   1.445 1 . 1 4 1   1 460

T a b l e 2 M e a n p a r t i c l e v e l o c i t y ( / ? = 2 4 cm )

R u n N o . U m [ m / s ] m c [ v o l% ] U s H [ m / s ] t / S j f f j B [ m / s ] £ 7 W i? [ m / s ] C 7 5 f [ m / s ] * 7 S F _ 7 i? [ m / s ]

H 0 862 6 580 0 703 0 81 7 0 834 X853 0 815

12 0 . 9 7 1 3 .0 7 0 0 . 7 9 7 1 . 0 2 4 0 .7 7 9 0 .9 2 2 0 .8 7 9

13 1 . 1 8 8 1 . 2 1 7 0 . 8 3 0

1 . 0 4 0 0 . 8 1 5 1 . 0 0 1 1 . 8 0 0

1 4 0 . 7 5 6

5 1

6 . 4 0 1 0 . 4 0 0

0 . 5 0 3   5 1 9 4 4

15 2 . 9 6 0

1 . 0 7 5 2 . 7 2 3

2 . 8 8 5

2 . 4 1 0

3 . 1 2 1 2 . 8 5 0

1 6 2 . 9 2 0 2 . 3 0 0 2 . 8 1 4 2 . 9 7 1 _  

17 1 . 7 7 4 3 . 6 5 3

1 . 4 1 9

1 . 6 1 5

1 . 3 4 0

1 . 6 4 3 1 . 7 2 8

1 8

1 . 9 5 2 0 . 7 1 5

1 . 6 4 5 1 . 6 9 0 1 . 6 3 9 2 . 1 5 1 1 . 7 3 7

19

1 . 8 6 6

1 1 7 1 1 . 5 2 0 1 . 7 1 5 1 . 4 8 6 2 . 0 4 5 1 . 7 3 8

20

1 . 1 2 2

3 . 2 4 2 0 . 6 7 0

0 . 9 7 4

0 . 7 1 0 0 . 9 1 2 0 . 9 2 9

2 1 1 . 3 8 2 1 . 6 7 3 1 . 0 4 2 1 . 3 0 4 0 . 9 6 3 1 . 3 2 7 1 . 3 3 7

2 2

2 6 7

3 .8 3 0 2 . 4 3 2 2 . 62 6 1 . 9 9 1

2 8 3 6 2 7 5

2 3 1 . 0 3

0 . 8 1 0 0 . 6 7 6

0 . 8 2 1

0 . 6 4 5 0 . 8 4 8 0 . 8 3 4

24

2 . 7 5 5

0 .3 7 4 2 . 7 5 4

2 . 7 8 5 2 . 1 8 6 2 . 7 1 7 2 . 8 8 0

2 5 2 7 2 0 . 9 2 6

2 . 5 4 1

2 .69 2 2 .0 8 8 2 7 5 9 2 6 2 1

T ab le 3 M ean partic le v e lo c ity U =48cm

R u n N o . U m [ m / s ] m c [ v o l% ] * 7 S iy [ m / s ] E / , M [ m / s ] U s h v b [ m / s ] J 7 s f [ m / s ] C / « V f l - s [ m / s ]

2 6 1 . 2 9 3 1 . 0 1 0   1.195 1 . 1 1 2

  1 186

2 7 0 .9 8 6 3 .4 6 0   0.688 0 . 6 3 8   0780

2 8

1 . 8 6 0 0 . 3 0 8

1 4 8 6

1 . 8 5 4 1 . 9 3 0 1 . 9 9 5 2 . 0 2 0

2 9 1 . 7 5 0 1 . 0 0 7   1.690

1 . 6 5 2

  1 909

3 0

1 . 5 5 0

3 7 2

1.315

1 . 2 2 1   1 579

31

2 . 8 8 0 0 . 5 8 3  

2.905

3 . 1 3 5   3191

3 2

2 . 8 4 0

1 . 1 7 1  

2.760 2 . 8 3 1   3055

3 3

2 7 5

3 . 2 2 3   2.640

2 . 5 4 5

  3010

3 4 0 . 9 65 0 .5 2 8 0 .6 6 8

0 . 7 7 4

0 . 8 4 9

0 . 8 3 7 0 . 6 4 0

2 E xp erim en ta l R esu lts an d D iscussio n

S om eexam ples o f th e cum ula tiv e distr ib utio n fun c-

t io n s o f th e p a r t ic le v e lo c i t ie s a re s h o w n in F ig s . 2 to 5 .

I n t h i s e x p e r im e n t , t h e m e a n p a r t i c l e v e l o c i t y U s i n

t h e tw o - p h a s e f l o w i s t h e v e lo c i t y a t w h ic h t h e c u m u -

la t iv e d is t r ib u t i o n f u n c t i o n is 0 .5 . T h e m e a n p a r t ic le

v e lo c i t i e s o b t a in e d a r e s u m m a r i z e d in T ab l e s 1 to 3 .

T h e s e f i g u r e s s h o w t h a t t h e p a r t i c l e v e l o c i t i e s a r e d is -

tributed over a w ide range because the flow path o f

e a c h p a r t ic le in a p ip e is d i f f e re n t . I n a d d i t io n , th e

m e a n p a r t i c le v e l o c i t y a t e a c h t e s t s e c t io n i s s t r o n g ly

a f f e c te d b y th e o p e ra t in g c o n d it io n .

2 .

1

P a r t i c l e

v e l o c i t i e s

in stra ig h t p ipe

a

H o r i z o n t a l p ip e

F ig . 6 s h o w s th e r e la t io n s h ip b e tw e en t h e m e a n p a r -

t ic le v e lo c ity in h o r iz o n ta l p ip e , U sh a n d th e m ean

v e l o c i t y o f s l u r r y J J m - U s h w h i c h i s n o t a f f e c t e d b y t h e

s m a l l c h a n g e o f c o nc e n tr a t i o n m c a s f o u n d in th is e x p er i -

m e n t , i s a lw a y s s m a ll e r t h an U m , a n d t e n d s t o a p p r o a c h

t h e v a lu e o f U m w i th in c r e a s in g f lo w r a te . A t lo w f lo w

r a te , a lm os t a l l p a r t ic le s f lo w a lo n g th e p ip e b o tto m

w i t h s m a l l e r v e lo c i ty t h a n U m . O n th e o th e r h a n d , a t

h i g h e r f lo w r a te U s h a p p r o a c h e s U m , b e c a u s e a lm o s t

a l l

par t i c l e s f l o w

t h r o u g h

th e

p ip e in s u s p e n s io n .

I n g e n e r a l , i t i s s a i d 8 ) th a t , i n th e f lo w o f s e t t l in g

s l u rr i e s , p a r t i c l e m o t i o n i s g ov e r n e d t o a l a r g e e x t e n t

b y th e d im e n s io n le s s t e r m U ll l g D { p s j p w - \ ) . I n th i s

c a s e a l s o , a s s h o w n i n F ig . 7 , t h e e x p e r im e n t a l d a t a a r e

c o r r e l a te d r e l a t i v e ly w e ll b y th e a b o v e d im e n s io n l e s s

t e r m th ro u g h t h e f o l l o w i n g e m p ir i c a l e q u at io n .

(U s H I U m ) = 0 .5 3 (U H g D (p s lP w - ) ) < » . « ( 1 )

b V e r t ic a l p ip e

F ig . 8 s h ow s t h e r e l a t i o n s h ip b e tw e e n t h e m e a n p a r -

t ic le v e lo c ity in v e r tic a l p ip e , U sy an d U m . T h e e f f e c t

o f m c o n U s V c a n b e n e g l e c t e d , s im i l a r l y t o t h e c a s e o f

t h e h o r i z o n t a l p i p e . H o w e v e r i t i s d i f f e r e n t f r o m t h a t

o f th e h o r iz o n ta l p ip e in th e c a s e w h en U m is g re a te r

th an a b o u t 2 m / s e c . T h at is , U s V b ec o m e s l a rg e r th an

[ 7 m , a s s h o w n in

F i g .

8 . I t w as obse rved

t h a t , w it h

in c re a s in g f lo w ra te o f s lu r ry , th e p a r t ic le s in th e v e r ti -

c a l

p i p e

t e n d to cong r ega t e n e a r t h e a x i s ,

w h e re th e

fluid flow s w ith h ig her ve loc ity . T h is show s th e reason

f o r t h e p a r t i c u la r p h e n o m e na m e n t io n e d a b o v e .

T h e e x p e r im e n t a l d a t a c o u l d b e c o r r e l a t e d a s w e l l a s

i n th e c a s e o f h o r iz o n t a l f l o w , a s s h o w n i n F i g . 9 , a n d

th e f ollo w in g e qu atio n w a s o b ta in ed .

( U , r I U m ) = 0 . 7 2 ( U l l g D ( P s lp w - I ) ) - . (2 )

14 2

JO U RN ALO F C HE M IC ALE NG IN EE RIN G O FJA PA N

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 4/7

2

Q . å å .

å

å .

å å

å

i

' å å å ' å i

å å

0 à" 3 .0 2 r c iw

d ,* 0 . 1 8 9 a i m

/ > « 2 . 5 l ^ / c m * }

In o 0 . 3 1 - 0 . 5 3

_ _ ^ ^ -

10 o 0 . 7 2 - 1 . 2 2

 ^

'I l ^J-% ^^

f e l 0 . 6 -

^ ~~~-Si* \

0.4 - fmpiricfll E<j

D s h .0 , 3 - [ 'V '0 & j ° 2

Q pl 1

1

1 1 1 > « - 1

1 1

å I 2 4

6 8

10

2 0 4 0

g D ( W I )

F i g . 7 R e l a t i o n s h i p b e t w e e n ( U s H /U m ) a n d

UllgD(Pslpw -l)

30

D = 3 . 0 2

c c m D / / -

d s

=

0 . 1 8 9

c c n o - f y s

ft= 2 .5 C g / c r r f r J ^ >

mc C 3 //

0 .3 1 - 1 .0 8 /

o I 1 7 2 5 0 q ® /

20

k > -3 . 0 0 - 5 .0 1 " y

1 - ^ - u m ^

, , _ ^ 1

^

,

1

,

1   1

0

1. 0

2 . 0 3 . 0

0 m C m / s 3

F i g . 8 P a r t i c l e v e l o c i t y i n v e r t i c a l p i p e

0 * 3 . 0 2 c c m }

d < =

O .I 8 9 c c n o

o 0 .3 1- 0. 53

© 0.72-1.22

à 1.67-5.01

f m p i r i c o l E ( j .

~ଠ'0-72 \ q D ( P J P m - \ ) \

2 0 3 0

F i g . 9 R e l a t i o n s h i p b e t w e e n ( U s v l U m ) a n d

V ilgD lp.lpw - l)

30 0 = 3 . 0 2 a m : / ~ ~

R = 12 a i m a /

d s = O . I 8 9 a m 3

.

/ *

^ = 2 . 5

C g / c n f t ^ ' >^

mcC ^ / y^

.0 ® 0.44-0.47 /~^S®

rn O 0 .7 5 - 1 .4 I / / /

S © 2 . 8 7 - 3 . 5 0 / å > i

J n /y/

å /

o^ j I 1 1 1 L I

0

1.0

2 . 0 , 3 . 0

U m C m/sD

F i g . 1 0 P a r t i c l e v e l o c i t y i n h o r i z o n t a l b e n d

3.o-

D s 3 . 0 2 c c r m . / _

R = 2 4

c c r m ) ®

d sn 0 . 1 8 9 c c r m ^ ^

 t=

2 .5

C g / c m 3 ] > ^

m e C % ) I / /

®

0 .3 7 ^ - 1 .0 8 \ , y

2. 0 //

-j

o 1 .1 7 - ^2 .5 0 / /

e à < { > å

3 .0 0 - - 5 .0 I / 4 r ® l

J -

D s H B = U m / / ?

i.o k å

l / X

i

 

0 1. 0 2 . 0 3 . 0

Um

C m / s D ^

F i g . l l P a r t i c l e v e l o c i t y i n h o r i z o n t a l b e n d

 30~ D=3.02 CcmD" ~~¥~

  R-48 ccrru j£

  ds- å0.1 89ccm3 /©

  Ps* 2.5 Gg/cm3] ^/^

  mc C%] //

 2.0- ® 0.3I-*-0.53 ~~~//

« o 1.00-I.17 /(/

\ © 3.22-3.72 /7

10-^

  //

  / , 1 , 1 L

  0 1.0 2.0 3.0

  UmCm/s]

F i g . 1 2 P a r t i c l e v e l o c i t y i n h o r i z o n t a l b e n d

3 . 0 . < - 1

D - 3 . 0 2 c c n o

d s = 0 . I 8 9 c c m n

me

«

3 .

23-5.00^-^^ ~^x^.

ro/-lI /^ ~~ 0

 ^X Dm-

. 5 ( m /s l

2 . 0

c^ - ^ _ _ J

^ ^ ^ | -

I

m ^

Um=2.0

C m / s i '

m ^

l0 °_ , D m * -

1 . 5 O n / s j

®.

® ^_

Um =

1 . 0 I m /s . 1

å t 1

0 10

2 0 3 0 « »

R / a C - :

F i g . 1 3 E f f e c t o f R ja o n p a r t i c l e v e l o c i t y i n h o r i z o n t a l b e n d

r

~

~

[7 1

3.0-à

D=

3 .0 2 c c r m ~ >

R

*1 2 c c m ; > /

ds = 0 .I 8 9 a r m /

9% -

2. 5

C g / c m * ] /

/

2. 0

-90.44-0.47 / >/^' ~

5 o 0 . 7 5 - 1 . 4 1 / j/s fs '

^ -< ^ 2 .8 7 - 3 . 4 9 / X X y

J IW U ny/ //^

\ / ,   L _ . L

1. 0

2 . 0 3 . 0

U m C r n /s 3

F i g . 1 4 P a r t i c l e v e l o c i t y i n v e r t i c a l b e n d w it h

h o r i z o n t a l a p p r o a c h f l o w

V O L . 6

N O .2 1 9 7 3

1 4 3

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 5/7

 

30 D = 3 0 2 ccm:- , 7

R = 2 4 [ c m : /

d s= 0 . I 8 9 c c m 3 /

P ss 2. 5 C g / c m 3 3 /

«JX> / X

® 0 / 3 7 - 1 . 0 8 / yf

,:2-°-o..7250 /-/ -

| ^ 3 . 0 0 - 5 . 0 1 / @ / ^

i ~ D m - - D s H V B / ®-^K

0   1 0

2. 0

3 . 0 .

U m C m /s 3

F i g . 1 5 P a r t i c l e v e l o c i t y i n v e r t i c a l b e n d w i t h

h o r i z o n ta l a p p ro a c h f l o w

30--

D = 3 . 0 2

c c m ]

/ //.

R=48 Lcmj /P]/

ds = 0 . 1 8 9 C c m ] // /

ps~- 2.5 Cg/cm3] / K

mc[%] /// /

0 . 3 1 - 0 . 5 3 / / / /

2.o /// y

-V°

1-0 I-1 .17 //A/

I < > - 3 . 2 2 - 3 . 7 2 J y y

1  

U SH V b - U m / / /

/ //

/ I I J

I I I

0 1. 0

2 . 0 3 . 0

D m C m /s ]

F i g . 1 6 P a r t i c l e v e l o c i t y i n v e r t i c a l b e n d w it h

h o r i z o n ta l a p p ro a c h f l o w

 _ i r j

D * 3 . 0 2 rc n u

 s - 0 . I 8 9 c c i m

f t = 2 . 5 l e g / c m 3 ] ' _----<> : °

m s = 3 . 0 0 ^ 3 . 7 2 C % 3 ^~~^ H b-2.5 C m /s D

J °^ e   ' Um=2.0Cm/a]

1 . 0 - ' å å å ' å L ^ | ° ' - - 1 . 5 C m / s i .

er- Dm ' I.O On /s:

t - ^ > J

  1  

1 J

  10

2 0 3 0 « >

R / a c - 3

F ig . 17 E ffec t o f R ja on pa rtic le ve lo c ity in v e rtic a l

b e n d w i t h h o r i z o n t a l a p p r r o a c h f l o w

3.o- D=3.02 ccrro [ . y -

R = 1 2 å à c c m n

. /\

d s = 0 . I 8 9 c c i m

/

ps = 2 . 5 ;

C g / c m 3 }

. / ^ /

® 0.44 0.47 ^y?< /

rn 2 .0 å

o

0 . 7 5 - à 1 . 4 1

~//s®/ ^^

^

-$ -

2 . 8 7 - 3 . 4 9 / 4 y /

/

/

/

/

Z I

: I

I   1 1 1

0 1 0 2 . 0 3 . 0

D m C m / s ]

F i g . 1 8 P a r t i c l e v e l o c i t y i n v e r t i c a l b e n d w it h

v e r t i c a l a p p r o ac h f l o w

2 . 2 P a r t i c l e v e l o c i t i e s i n b e n d s

a ) H o r i z o n t a l b e n d s

T h e m e a n p a r t i c l e v e l o c i t i e s i n h o r i z o n t a l b e n d s ,

U shb> are show n in F ig s . 10 to 12. In any rad iu s o f

c u rv a tu re , U s H Bis n o t a f f e c t e d b y m c u n d e r th i s e x pe r i -

m e n t a l c o n d i t i o n , a n d i t i s n e a r l y p r o p o r t io n a l to U m .

T h e s l o p e o f U s h b v s - U m i n c r e a s e s g r a d u a l l y w it h t h e

in c re a se o f rad iu s o f cu rv a tu re . In th e case o f R =24

c m , th e s lo p e is n e a r ly e q u a l to th a t in h o r iz o n ta l p ip e ,

and in th e ca se o fR =48 cm th e s lo p e becom es g rea te r

t h a n th a t in h o r iz o n ta l p ip e . T h e s e p h e n o m en a c o u ld

b e c a u s e d b y m a n y f a c t o r s , s u ch a s s e c o n d a r y f l o w o f

f lu id , c e n t r i f u g a l f o r c e a n d th e f r ic t io n f o r c e b e t w e e n

p ar t i c l e s a n d p ip e w a l l .

F ig . 1 3 s h o w s t h e e f f e c t o f R j a o n U s H b m h o r i z o n t a l

b e n d s . I t is f o u nd th a t U s H B in c r e a s e s w ith in c re a s in g

R ja

u p t o abou t Rja=20 , b u t t h e n

i t d e c r e a s e s

g r a d u a l l y . T h i s i s p r e s um e d to b e d u e to t h e f o l l o w -

i n g r e a s o n s ; i ) A t h i g h f l o w r a t e , t h e f r i c t i o n f o r c e b e -

tw

p a r t i c l e s

a n d

p i p e w a l l

i n c r e a s e s be c a u se th e

c e n t r i f u g a l f o r c e . a c t i n g o n t h e p a r t i c l e i n c r e a s e s w it h

d ec r e a s e o f R j a . i i ) . A s R j a b e c o m e s s m a l l , t h e c h a n g e

o f d ir e c t io n o f th e p a r t i c le m ot io n p e r u ni t l e n g th o f th e

p ip e b e n d b e c o m es la rg e a n d th e in e r t ia o f th e p a r t ic le s

d e c r e a s e s . W h e n R [ a b e c o m e s in f in i te , U .s h - b w ^ a P

p r o a c h U s h i n t h e h o r i z o n t a l p i p e ,

b ) V e r t i c a l b e n d s w ith h o r i z o n ta l a p p r o a c h f lo w

Th e

mean p a r t i c l e

v e l o c i t ie s in

v e r t i c a l b e n d s ,

U S H V B > a r e s h o w n v s . U f a i n F i g s . 1 4 t o 1 6 . I n a n y

r a d iu s o f c u rv a t u r e , U sh v b 1 8 n e a r l y p r o p o r t io n a l to U m

a n d t h e e f f e c t o f m c o n U s h v b a p p e a r s i n t h e c a s e s o f

i ^ = 1 2 a n d 4 8 c m . I n t h e s e f i g u r e s , t h e s l o p e o f U s h v b

v s . Um i nc re a se s w i t h i n cr e a s i n g R . T h i s t e n d en c y

a g r e e s w i th th a t in th e h o r i z o n ta l p ip e b e n d s . I n th e

c a s e s o f R = 1 2 a n d 2 4 c m , t h e s l o p e o f U s h v b ^ s s m al l e r

th a n un ity. O n t h e o th e r h an d , in th e c ase o f R = 48

c m t h e s l o p e i s n e a r l y e q u a l t o t h a t i n t h e h o r i z o n t a l

p i p e . _

F ig . 17 sh ow s th e e ffe c t o fR ja o n U sHVB . At h igh

f l ow r a t e ,

UsHVB

in c rea se s

w i t h i n c r e a s in g

R ja a n d

app roache s th e va lu e o f U sh-

c ) V e r t ic a l b e n d s w ith v e r t ic a l a p p ro a c h f lo w

T h e b e h a v i o r o f p a r t i c l e s i n b e n d s i s m u c h c o m p l i -

c a t e d

b y

th e effect o f g ra vi t y , c e n tr i f u g a l f o r c e a n d

s e c o n d ar y f l o w o f f l u id . T h e f l o w s t a t e s o f h o r i z o n t a l

a n d v e r t i c a l b e n d s w it h h o r i z o n t a l a p p r o a c h f l o w a r e

d e t a i l e d in

th e

pr ev ious p a p e r 7 > .

P h o t o s . 1 a n d 2

s h o w t h e

f l ow

s t a t e s in v er t i c al b e n d s w i t h v e r t i c a l

a p p r o a c h f l o w . At low f l ow

r a t e ,

th e p a r t ic l e s a re

t r anspor t ed

in a

s t a t e o f

suspens ion in th e ben d . A t

h ig h f l o w r a te , a s s h o w n i n P ho t o . 2 , a lm os t a l l p a r t ic l e s

a r e t r a n s p o r te d a l o n g t h e o u ts i d e w a l l o f t h e b e n d , a s

w e l l a s i n h o r i z o n t a l a n d v e r t i c a l b e n d s 7 } b e c a u s e t h e

14 4

JO U R NA LO F C H EM IC A LE NG IN EE R IN G O F JA PA N

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 6/7

F lo w d ir ec tio n

R=24cm, U =O .i

Sm/s,

2.20vol^

P hoto. 1 Flow state for low flow rate in vertical

b en d w i t h v e r t i c a l a p p r o a c h f l o w

F lo w d ire ctio n

R=24cm,

U =2.54m/s,

Photo. 2 Flow state for h igh flow rate in vertical

b en d w i t h v er t i c a l a p p r o ac h f l o w

3.o--D

= 3 . 0 2 C cm : V -

R = 2 4 c c n o / ®

ds = 0 . 1 8 9 c cm ) - ^ f

i ° s = 2 .5 C g / c m 3 ] ^ /

mc % ] / ^

20

à 0 . 3 7 - 1 . 0 8 y /

K

o I . 7 - - 2 . 3 0 /^ J

I

> 3 . 0 0 - 5 . 0 1 / < /

|

-

-0 S VHB-U m //

  zf

 /A

0 1. 0

2 . 0 3 .0

D m C m / sD

F i g . 1 9 P a r t i c l e v e l o c i t y i n v e r t i c a l b e n d w it h

vertica l ap proach flow

~ p P T~ ?

3-° D-3.02W //~

R

= 4 8 K m ] / /

ds = 0 . I 8 9 c c m : / /

Ps = 2 5

[ g / c m 3 ] / /

m c C % ) ' //

® 0.31 .0.53 ^ //

 

0 å ®//- å

< o 1 . 0 0 - - - . 1 7 c ) / /

1 ^ 3 .2 2 - - 3 . 7 2 j /

^   UsVHB=D m //

/Y

/f t

/ | ; , . 1

0

1. 0

2 . 0 3 . 0

U m C m / s ]

F i g . 2 0 P a r t i c l e v e l o c i t y i n v e r t i c a l b e n d w it h

v e r t i c al a pp ro ac h f lo w

fD

« 3 . 0 2

C c n t f 1 f

( f 9 *

0 . 1 8 9 o t r r o

_ _ - - - Q

-me'

3 2 2 - 3 . 7 i%l^^^^ u»°2-5 ^^

^ 2.0 j ^^ {^=2.0 Crn/^

j- T ^ à å - ^ . -

O t n = 1 .5 t m /s ]

r 0 , . _ - i 4~- ;- å å -

0ffl=

1 . 0 C m / s ]

X* I .I

I

i [ . t i _ T

0

10

2 0 3 0 ° °

R /a C - 3 . 4 ^ .

F i g . 2 1 E f f e c t o f R ja o n p a r t i c l e v e l o c i t y i n v e r t i c a l

b en d w i t h v e r t i c a l a p p ro ac h f l o w

D = 3 .0 2 c c /m

3l ° d s = 0 . I 8 9 c c r r n , / » , « 2 . 5 C g / c m 3 ]

mc=3. 2 2 - 3 . 7 2 C % 3 /- R «no

2

.o - ' -o ' KyJ D m = 2 - 5 C m / £

\

/   , . H . P I

  N--o^

U «

» i o ^ T

  f

i

 

H.P H-H.B H.P H-V.B V.P V-H.B H.P

F i g . 2 2 C h a n g e o f p a r t i c l e v e l o c i t y a t e a c h f l o w p a t h

p a r t ic le s a r e s t r o n g ly a f f e c te d b y in e r t ia l a n d c e n t r i f -

u g al f o rc es .

F i g s .

1 8 to 2 0

show

th e

r e l a t i o n s h i p

between th e

mean

p a r t i c l e

v e l o c i t i e s UsVHB

a nd

Um

in v ertica l

b e n d s . T h e e f f e c t o f m c o n U s v h b d o e s n o t a p p e a r w it h

t h e e x c e p t i o n o f R = 1 2 c m , a n d i n a n y r a d i u s o f c u r v a -

tu r e U sv h b is n e a r ly p r o p o r t i o n a l to U m >I t i s c l e a r ly

s e e n f r o m th e s e f i g u r e s t h a t th e s lo p e o f U sv h b v s - U m

in c r e a s e s w ith in c r e a s in g R . T h is te n d e n c y i s s im i la r to

t h e c a s e o f h o ri z o n t a l a n d v e r t i c a l b en d s w i t h h o ri -

z o n t a l a p p r o a c h f l o w . I n t h e c a s e o f R = 4 8 c m , t h e

s l o p e i s

g r e a t e r than t h a t in

t h e

v e r t i c a l p ip e . T h e s e

phenomena are similar to the case of horizontal bends.

I t

is

c o n s i d e r e d t h a t , a t h i g h f l o w r a t e ,

almost a ll

p a r t i c l e s a r e t r a n s p o r t e d a l o n g t h e o u t s i d e w a l l o f t h e

b e n d b y h ig h e r f lu id v e lo c i ty n e a r th e o u ts id e w a l l .

F ig . 2 1 s h o w s th e e f f e c t o fR /a o n U s v h b - A t l o w f l o w

r a t e , U s v h b

tends to i n c r e a s e w i t h

d e c r e a s i n g R ja .

O n th e o th e r h a n d , a t h ig h f lo w r a t e C / s v h b d e c r e a s e s

w it h d e c r e a s i n g R \a a s w e l l a s t h e o t h e r b e n d s d e -

s c r i b e d i n t h e p r e v i o u s s e c t i o n s . A s t h e r a t i o o f R ja

b e c o m e s in f in i t e , U s v h b w ^ a p p r o a c h U s v in th e v e r -

t i c a l p i p e .

2 . 3 Comparison of th e velocities in each test

section

T h e m e a n p a r t i c l e v e l o c i t y i n e a c h t e s t s e c t i o n u n d e r

c o n s t a n t m c i s s h o w n in F ig . 2 2 . T h e v e l o c i t y in t h e

v e r t ic a l p ip e is a lw a y s g re a te r th a n th a t in th e h o r iz o n -

t a l p i p e . T h i s i s d u e t o t h e f a c t t h a t i n t h e v e r t i c a l p i p e

t h e p a r t i c l e s t e n d to m o v e p r e f e r e n t i a l l y n e a r t h e a x i s

V O L . 6 N O .2 : 1 9 7 3 -

14 5

7/23/2019 Toda-1973-ON THE PARTICLE VELOCITIES IN SOLID-.pdf

http://slidepdf.com/reader/full/toda-1973-on-the-particle-velocities-in-solid-pdf 7/7

in acco rd ance w ith an in c rea se o f U m w hile in th e

h o r i z o n t a l p i p e m o s t o f t h e p a r t i c l e s a r e a lw a y s t r a n s -

p o r t e d n e a r t h e p i p e b o t t o m b y t h e f l u i d a t a r a t e

m uch s low er th an th a t o f m ean f low 6 . M oreo ve r

F ig . 2 2 s h o w s t h a t t h e m e a n p a r t i c l e v e l o c i t y i n v e r t i c a l

b e nd s

w i th h o ri z o n ta l a pp r o a c h f l ow is t h e s m a ll e s t

a m on g th o s e i n a l l p i p e b e n d s .

3 C o n cl u si o n

T h e f l o w s t a t e s i n t h e b e n d s w e r e o b s e r v e d f o r s o l i d -

l i q u i d tw o - ph a s e f l o w . Th e

p a r t i c l e v e l o c i t ie s i n

s t r a i g h t p i p e s a n d b e n d s w e r e m e a s u r e d a n d t h e f o l l o w -

in g re sults w ere o bta in ed .

i ) U n d e r t h e e x p e r im en t a l c o n d i t i o n s o f f 7 m = 0 . 7 to

3 . 0 m /s a n d m c = 0 . 3 t o 5 . 0 v o l , t h e m e a n p a r t i c l e

v e l o c i t i e s i n s t r a i g h t p i p e s a n d b e n d s a r e n e a r l y p r o -

p o r t i o n a l t o U m .

i i ) T h e m ea n p a r t i c l e v e l o c i t i e s i n t h e v e r t i c a l p i p e

a r e g r e a t e r t h a n t h o s e i n t h e h o r i z o n t a l p i p e ,

i i i ) E m p i r i c a l e q ua t io n s e x p r e s s in g th e m e a n p a r t i c l e

v e l o c i t i e s i n h o r i z o n t a l a n d v e r t i c a l p i p e s a r e p r o p o s e d ,

a s g i v e n b y E q s . l ) a n d 2 ) . T h e s e e q u a t i o n s g iv e th e

m ea n p a r t ic l e v e lo c i t y w ith in 1 0 e r r o r .

i v ) T h e m e a n p a r t i c l e v e l o c i t i e s i n v e r t i c a l b e n d s w it h

h o riz o nta l a pp ro a ch flo w a re a lw a y s sm a l le r th a n th o se

i n t h e o t h e r b e n d s .

v ) T h e e ff e c t o f r a d i u s o f c u r v a t u r e o n p a r t i c l e v e l o c -

i t i e s b ec o m e s s i g n i f i c a n t a s t h e m e an f l o w r a t e i n c r e a s e s

a n d /o r t h e r a d i u s o f c u r v a t u r e d e c re a s e s .

A c kn ow le d ge m e nt

T h i s w o r k w a s s u p p o r t e d b y t h e S c i e n c e R e s e a r c h F o u n d a t i o n

o f E du c a t io n a l M i n i s t r y , J a p a n , G ra n t N o . 5 0 1 6 5 . T h e a u t h o r s

a p pr e c i a t e t h e s u pp o r t l e a d in g to t h e p ub li c a t io n o f th is a r t i c le .

N o m e n c l a t u r e

  radius of pipe m]

= diameter of pipe [m]

= cum u la t iv e d is t r ib u t io n fu n c t io n [ -]

= acceleration due to gravity [m s2]

= c o nc e ntr a t io n o f s o lid s in m ixtu re d is c ha rg ed

from end of pipe vol ]

= radius of curvature of bend [cm]

= mean velocity of slurry [m s]

= particle velocity [m s]

= mean particle velocity [m s]

= m ean pa rtic le ve lo c ity in h o rizon ta l pipe [m /s]

= m e a n p a r t ic le v e lo c i ty in ve r tic a l p ip e [m /s ]

= m ean pa r t ic le v e lo c i ty in h o r iz o n ta l b e n d [m /s J

= m e an pa r t ic l e v e lo ci ty in v e r t ic a l b en d

w ith h o r iz o n ta l a pp ro a c h f lo w [m /s ]

= m ea n p a r t i c le v e lo c i ty in v e r t i c a l b e n d

w ith v e r t ic a l a p p ro a c h f lo w [m /s ]

= d e n s i ty o f p a r t i c l e [g /c m 3]

= density of water [g crn3]

L i t e r a t u re C i t e d

1 ) A yu k a w a , K . : P r e p r in t s f o r 4 7 t h A nn u a l M ee t in g o f J . S - M . E .

No

2 1 6 1 9 6 9

2 D u r a n d , R . : L a H o u i l l e B l a n c h e , 8 , 1 2 4 1 9 5 3

3 I k i , S . a n d Z . H o k a o : M M I J , 8 4 , N o . 9 5 7 , 1 5 1 9 6 8

4 M u r o t a , A . : J S C E , 3 8 , 4 7 8 1 9 5 3

5 ) N ew it t , D . M ., J . F . R i c h a r d s o n a n d C . A . S h o c k : P r o c e e d i n g s

o f th e Sym po s iumo n th e In te ra c tio n b e tw een F lu id s a n d

P a r t i c l e s 8 7 , L o n d o n , I n s t . G h e m . E n g r s . 1 9 6 2 )

6 ) T o d a , M ., H . K o n n o , S . S a i t o a n d S . M ae d a : K a g a k u K o g a k u ,

3 3 , N o . 1 , 6 7 1 9 6 9 )

7 ) T o d a , M ., N . K o m o r i , S . S a i t o a n d S . M ae d a : J . C h e m . E n g .

J a p a n , 5 , N o . 1 , 4 1 9 7 2

8 ) T e r a d a , S . : P r e p r i n ts fo r 4 0 th A nn u a l M ee t i n g o f J . S . M . E . ,

No

8 6 ,

1 3 7 1 9 6 3

1 4 6

JO UR NA LO F C HE MIC AL E NG IN EER IN G O FJA PA N