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DESIGN INFORMATION AND DATA
8.8.2. Liquids
The data available in the literature up to 1973 have been reviewed by Jamieson et al.
(1975). The Weber equation (Weber, 1880) can be used to make a rough estimate of the
thermal conductivity of organic liquids, for use in heat-transfer calculations.
4 1/3
5
k D 3.56 ð 10 C p 8.12
M
Ž
where k D thermal conductivity. W/m C,
M D molecular mass,
Ž
C p D specific heat capacity, kJ/kg C,
3
D density, kg/m .
Bretsznajder (1971) gives a group contribution method for estimating the thermal conduc-
tivity of liquids.

Example 8.4
Ž
Estimate the thermal conductivity of benzene at 30 C.

Solution
Ž
Density at 30 C D 875 kg/m 3
Molecular mass D 78
Ž
Specific heat capacity D 1.75 kJ/kg C
875
4 1/3
Ž
k D 3.56 ð 10 5 ð 1.75 D 0.12 W/m C (8.12)
78
Ž
Experimental value, 0.16 W/m C
8.8.3. Gases

Approximate values for the thermal conductivity of pure gases, up to moderate pressures,
can be estimated from values of the gas viscosity, using Eucken’s equation, Eucken (1911):
10.4

k D C p C 8.13
M
2
where D viscosity, mNs/m ,
Ž
C p D specific heat capacity, kJ/kg C,
M D molecular mass.

Example 8.5
Ž
Estimate the thermal conductivity of ethane at 1 bar and 450 C.