Fluids / Dry air

Thermal conductivity of dry air vs temperature

Thermal conductivity in W/(m·K), from -50 to 300 °C. The chart and the table below are the same numbers; the table is the one you can copy.

Thermal conductivity W/(m·K)
Thermal conductivity of dry air in W/(m·K), from -50 to 300 °C-23.15 °C — 0.02227 W/(m·K)26.85 °C — 0.02624 W/(m·K)76.85 °C — 0.03003 W/(m·K)126.8 °C — 0.03365 W/(m·K)176.8 °C — 0.03707 W/(m·K)226.8 °C — 0.04038 W/(m·K)0.0220.0240.0260.0280.030.0320.0340.0360.0380.040.0420.044-40-20020406080100120140160180200220240260280300Temperature (°C)Thermal conductivity (W/(m·K))
Dry air — everything else at 20 °C (default)
Density1.2041 kg/m³
Dynamic viscosity0.018133 mPa·s
Specific heat1.0068 kJ/(kg·K)
Thermal conductivity by temperature
Temperature (°C)Thermal conductivity (W/(m·K))Row
-500.020071interpolated
-250.02212interpolated
00.024128interpolated
250.026096interpolated
500.028017interpolated
750.029893interpolated
1000.031729interpolated
1250.03352interpolated
1500.035253interpolated
1750.036945interpolated
2000.038622interpolated
2250.040261interpolated
2500.041846interpolated
2750.043397interpolated
3000.044933interpolated

Rows marked published land exactly on a source anchor and are the tabulated figure. The rest are this library’s interpolation between the two anchors either side — good enough to design with, and said out loud so you can decide that for yourself.

Ideal gas law with R = 287.0528 J/(kg·K); Sutherland (1893) viscosity; Incropera, Fundamentals of Heat and Mass Transfer, Table A.4 for cp and k · validated -50 to 300 °C · interpolated between 8 published anchors (values held, not extrapolated, past the ends)