Environmental Engineering Reference
In-Depth Information
1˚F =
(5/9)
K
T
˚C =
T
K - 273.15
T
˚C =
5/9(
T
˚F - 32)
T
˚F =
T
˚R - 459.67
Thermal conductivity
1 Btu/h·ft˚F =
1.7307
W/m·K
1 kcal/m·h˚C =
1.163
W/m·K
1 cal/cm· s˚C =
418.68
W/m·K
Thermal resistance
1˚F/Btu·h =
1.896
K/W
1 ft
2
·˚F/Btu·h =
0.1761
m
2
K/W
1 m
2
h˚C/kcal =
0.8598
m
2
K/W
Viscosity (µ)
1 kg/s·m = 1 N·s/m
2
=
1.0
Pa·s
1 lbm/ft·h =
4.1338 × 10
-4
Pa·s
1 lbf·h/ft
2
=
1.7235 × 10
5
Pa·s
Volume
1 liter(l) =
0.001
m
3
1 in
3
=
16.39
cm
3
1 ft
3
=
0.02832
m
3
1 yd
3
=
0.7646
m
3
1 gal(U.S.) =
3.785
l
1 gal(imperial) =
4.546
l
1 pint =
0.5683
l
1 fluid ounce =
0.029
l
Volumetric heat generation rate
1 Btu/h· ft
3
=
10.3497
W/m
3
1 kcal/m
3
·h =
1.163
W/m
3
B.2
NONDIMENSIONAL PARAMETERS
Reynolds number
Re
=
uL
/ν
ν = kinetic viscosity = µ/ρ
m
2
/s
ρ = density kg/m
3
µ = molecular viscosity Pa·s
Prandtl number
Pr
=
ν /
a
or (
gc
p
µ)/λ
a
= thermal diffusivity = λ /ρ
c
p
m
2
/s
λ = heat conductivity W/mK
Peclet number
Pe
=
Re Pr =
uL
/
a
Nusselt number
Nu =
hL
/λ
h
= heat transfer coefficient W/m
2
K
Grashof number
Gr
=
(
g
β
L
3
∆
T
)/ν
2
β
= volume coefficient of expansion
g
= gravity
L
= characteristic length
T
= temperature difference
Graetz number
Gz =
Re Pr (
d
/
L
)
d
= inner diameter of tube m
L
= tube length m
Mach number
M =
u
/
u
sound
u
sound
= sound velocity
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