Page 142 - Mechanical Engineer's Data Handbook

THERMODYNAMICS AND HEAT TRANSFER 131

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ob 1 2 3 4

3.14.2 Thermal conductivity coefficient
The fo1low;i;g table gives values of conductivity for
solids, liquids and gases.

Thermal conductivity coeffieients (W tn-l K-') at WC and 1 bar

Metals Liquids Plastics
Aluminium 239 Benzene 0.16 Acrylic (Perspex) 0.20
Antimony 18 Carbon tetrachloride 0.11 Epoxy 0.17
Brass (60/4Q) 96 Ethanol 0.18 Epoxy glass fibre 0.23
Cadmium 92 (ethyl alcohol) Nylon 6 0.25
Chromium 67 Ether 0.14 Polyethylene :
Cobalt 69 Glycerine 0.29 low density 0.33
Constantan 22 Kerosene 0.15 high density 0.50
Copper 386 Mercury 8.80 PTFE 0.25
Gold 310 Methanol 0.21 PVC 0.19
Inconel 15 (methyl alcohol)
Iron, cast 55 Oil: machine 0.15 Refrigerants at critical
Iron, pure 80 transformer 0.13 temperature
Lead 35 Water 0.58
Magnesium 151 Ammonia (132.4"C) 0.049
Molybdenum 143 Gases Ethyl chloride (187.2"C) 0.095
0.076
Freon 12 (112°C)
Monel 26
Nickel 92 Air 0.024 Freon 22 (97°C) 0.10
Platinum 67 Ammonia 0.022 Sulphur dioxide (157.2") 0.0087
Argon
0.016
Silver 419 Carbon dioxide 0.015 Insulating materials
Steel: mild 50 Carbon monoxide 0.023
stainless 25 Helium 0.142 Asbestos cloth 0.13
Tin 67 Hydrogen 0.168 Balsa wood (average) 0.048
Tungsten 172 Methane 0.030 Calcium silicate 0.05
Uranium 28 Nitrogen 0.024 Compressed straw slab 0.09
Zinc 113 Corkboard 0.04
Oxygen 0.024 0.029
Water vapour 0.016 Cotton wool
Diatomaceous earth 0.06
Diatomite 0.12
Expanded polystyrene 0.03/0.04