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total head loss discharge coefficient

head

(Munson et al., 2010)

constant2

2

zg

V

g

P (1)

P (Pa)

V (m/s)

z (m)

(kg/m3)

g (m s2)

2

222

1

211

22z

g

V

g

Pz

g

V

g

P (2)

gP pressure head (m) gV 22 velocity head z elevation head

21 zz pressure head velocity head total head (m)

( ,

2556)

total head loss, losstotalh , ,

g

V

g

P

g

V

g

Ph FFAA

losstotal 22

22

, ( )

discharge coefficient, DC ,

21

2

AC

CACD

AA

hhgAQC ( )

Q (m3/s)

h pressure head (m) = gP

A (m2)

CA,

1. valve rotameter L/min

valve L/min , 15

L/min

Flow rate (L/min) hA (mm) hB (mm) hC (mm) hD (mm) hE (mm) hF (mm)

30 510 459 1 301 476 503

25 497 461 143 350 471 491

20 481 457 253 385 462 476

15 475 461 346 419 462 471

10 466 459 407 438 457 463

pressure

head velocity head

pressure head velocity head

pressure head A velocity head

pressure head A B C

A B C

velocity head A B C velocity head pressure

head

0.0

100.0

200.0

300.0

400.0

500.0

600.0

A B C D E F

Hea

d (m

m)

Tube position

h (mm)

v2/2g (mm)

C D, E F velocity head

pressure head

pressure head A F

total head loss

total head loss

total head loss

pressure head

A F total head loss

Darcy-Weisbach equation (Munson et al., 2010)

g

V

D

Lfhloss 2

2

( )

f friction factor

L (m)

D (m)

lossh VAQ head loss

012345678

0 10 20 30 40

Hea

d lo

ss (m

m)

Flow rate (L/min)

discharge coefficient

discharge coefficient

discharge coefficient

0.98 venturi (Munson et al., 2010)

total head loss discharge coefficient

pressure head velocity head

total head loss total head loss - mm discharge

coefficient

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40

Dis

char

ge c

oeff

icie

nt

Flow rate (L/min)

C_av

C_D

Bruce R. Munson, Donald F. Young, Theodore H. Okiishi, Wade W. Huebsch. 2010. Fundamentals of Fluid Mechanics. 6th

edition.Singapore: John Wiley & Sons.

2. .

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