Air - Prandtl Number (original) (raw)

The Prandtl Number - Pr - is a dimensionless number approximating the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity - and is often used in heat transfer and free and forced convection calculations.

The Prandtl number can for calculations be expressed as

Pr = μ cp / k (1)

where

μ = absolute or dynamic viscosity (kg/(m s), (lbm/(ft h))

cp = specific heat (J/(kg K)), (Btu/lbmoF)

k = thermal conductivity (W/(m K)), (Btu/(h ft2oF/ft))

Below, Prandtl numbers for air at varying temperatures and pressures are given in figures and tables.

See also other properties of Air at varying temperature and pressure: Density and specific weight at varying temperature, Density at varying pressure, Diffusion Coefficients for Gases in Air, Specific heat at varying temperature and Specific heat at varying pressure, Thermal Conductivity, Thermal Diffusivity, Properties at gas-liquid equilibrium conditions and Air thermophysical properties at standard conditions and Composition and molecular weight,
as well as Prandtl number of Ammonia, Carbon dioxide, Methane, Nitrogen, Propane and Water .

Air Prandtl number at 1 bara pressure, temperature given as °C or °F:

Prandtl number C
Prandtl number F

Air Prandtl number at varying temperatures and constant pressures, SI and Imperial units:

Prandtl number pressure C
Air Prandtls number pressure F

Air Prandtl number at 1 bara pressure, temperature given as °C or °F:

Air - Prandtl Number at 1 bara Pressure

Temperature Pr Temperature Pr
(°C) (-) (°F) (-)
-100 0.734 -150 0.733
-50 0.720 -50 0.719
0 0.711 0 0.714
25 0.707 60 0.709
50 0.705 75 0.708
100 0.701 100 0.706
150 0.699 200 0.701
200 0.698 300 0.699
250 0.699 400 0.698
300 0.702 500 0.700

Air Prandtl number at given temperatures and 1, 5 10 and 20 bara pressure:

Air - Prandtl Number

Temperature Prandtl number at given pressures
(K) (°C) (°F) 1 bara, 14.5 psia 5 bara, 72.5 psia 10 bara, 145 psia 20 bara, 725 psia
60 -213.2 -351.7 4.138 4.153 4.170 4.187
80 -193.2 -315.7 1.7 2.252 2.259 2.269
100 -173.2 -279.7 0.780 0.898 1.783 1.770
120 -153.2 -243.7 0.759 0.806 0.890 1.360
140 -133.2 -207.7 0.747 0.773 0.812 0.923
180 -93.2 -135.7 0.731 0.743 0.759 0.792
200 -73.2 -99.7 0.726 0.735 0.745 0.769
220 -53.2 -63.7 0.721 0.728 0.736 0.754
240 -33.2 -27.7 0.717 0.722 0.729 0.742
260 -13.2 8.3 0.713 0.718 0.723 0.734
273 0.0 32.0 0.711 0.715 0.720 0.729
280 6.9 44.3 0.710 0.714 0.718 0.727
289 15.6 60.0 0.709 0.713 0.716 0.723
300 26.9 80.3 0.707 0.711 0.714 0.722
320 46.9 116.3 0.705 0.708 0.711 0.717
340 66.9 152.3 0.703 0.705 0.708 0.714
360 86.9 188.3 0.701 0.703 0.706 0.711
380 106.9 224.3 0.700 0.702 0.704 0.709
400 126.9 260.3 0.699 0.701 0.703 0.706
500 226.9 440.3 0.698 0.700 0.701 0.703
600 326.9 620.3 0.703 0.704 0.704 0.706
700 426.9 800.3 0.710 0.710 0.711 0.712
800 526.9 980.3 0.717 0.718 0.718 0.719
900 626.9 1160.3 0.724 0.725 0.725 0.725
1000 726.9 1340.3 0.730 0.730 0.730 0.731
1100 826.9 1520.3 0.734 0.735
1500 1226.9 2240.3 0.743 0.743
1900 1626.9 2960.3 0.742 0.742

Air Properties - Density, Viscosity, Heat Capacity, Thermal Conductivity, and more

Air Properties - Density, Viscosity, Heat Capacity, Thermal Conductivity, and more

Thermal properties of air, including density, viscosity, thermal conductivity, specific heat and more at different temperatures and pressures. Comprehensive reference with formulas, tables, and charts to support engineering calculations.

Moist Air - Properties

Moist Air - Properties

Psychrometric table with humid air properties like saturation pressure, specific volume, enthalpy and entropy.

Solubility of Air in Water

Solubility of Air in Water

The amount of air that can be dissolved in water decreases with temperature and increases with pressure.