Environmental Engineering Reference
In-Depth Information
Table B.1
Fluid-solid and fluid-fluid interaction correlations.
Interaction
Correlation
Comment
Fluid-solid
Flow through circular pipe
Characteristic length
=
pipe diameter
Sh
=
1.86(
ReSc
)
0
.
8
(a) Laminar
Velocity
=
average fluid velocity in
Sh
=
.
026
Re
0
.
8
Sc
1
/
3
(b) Turbulent
0
pipe
Flow through non-circular
Use hydraulic radius to determine
cross-sections
equivalent diameter. Then use
above correlations
Forced convection around
6
Re
1/2
Sc
1/3
Sh
=
2
+
0
.
Characteristic length
=
sphere
a solid sphere
diameter
Velocity
relative velocity of sphere
and bulk fluid
=
Laminar flow across
Characteristic length
=
plate length
a flat plate
(a) Local value
322
Re
1/2
Sc
1/3
Sh
=
0
.
664
Re
1/2
Sc
1/3
(b) Average value
Sh
=
0
.
D
2
ω
Spinning disc
62
Re
1/2
Sc
1/3
Sh
=
0
.
Re
=
ν
D
=
disc diameter
ω
=
disc rotation rate
Packed beds of spherical
17
Re
−
0
.
42
Sc
−
0
.
67
k
/v
=
1
.
Characteristic length
=
particle
particles
diameter
v
=
superficial velocity
Fluid-fluid
Dispersed phase
0.13
L
4
(
W
/
V
)
ρv
Sc
1/3
Sh
=
L
=
stirrer length
=
characteristic
3
(drops or bubbles) in
length
stirred continuous phase
W
/
V
=
power per total fluid volume
m
3
)
ρ
L
=
liquid density, (kg
/
ρ
G
=
/
m
3
)
gas density, (kg
σ
=
liquid surface tension, (dyne
/
cm)
σ
c
=
critical surface tension of packing material, (dyne
/
cm)
Values of
σ
c
for selected materials are given in Table B.2.
Search WWH ::
Custom Search