Page 84 - Industrial Ventilation Design Guidebook

4,1 FLUID FLOW 49

TABLE 4.1 Constants for Water

Pressure Po = kPa
Temperature TO - 273.15 K
Density Po = 999.80 kg m" 3
2
3
Constant A A = 225.30 m K kg' 1
Velocity of sound c = 1400 m s~ T
n
3
Viscosity Mo = 1.791 xlO~ kg s~V
=
2
6
Kinematic viscosity V 0 - 1.791 xlO~ m s"'
Constant B B = 511.6 K
Constant: C >-> -149.4 K
1
Specific heat c p = 4182.6 J kg" K" 1
9
Modulus of elasticity E 0 = = 1.95xl0 NnT 2
4,1.3 Constants for Gases
The constants for various gases are listed in Table 4.2, where
P 0 = density
c 0 = velocity of sound
R = gas constant
/A O = dynamic viscosity
K = adiabatic constant

4.1.4 Properties of Air and Water Vapor

Air can be considered as an ideal gas, which has a definition

or

This is the state equation of an ideal gas, where p is pressure, v is specific vol-
ume, p is density, R is the gas constant, and T is absolute temperature. In an
airflow there is a transfer of heat from one layer to another. This change of

TABLE 4.2 Constants for Gases

Po C 0 ft J»o
1
(kgm-') (ms-') (Jkg-'K-') (kgs-'m- ) T
Air 1.275 332 287.04 1.717 xlO- 5 1 .402
O, 1.409 315 259.78 1.928 xlO-* 1.399
1.234 37 296.75 1.625 x 1(H 1.400
N 2
0.0887 4124.0 5
H 2 1260 8.350 x 10- 1.409
1.949 259 188.88 1.370 xlO- 5 1.301
CO 2
p () = 100 kPa, T 0 - 273.,15 K