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# Prandtl Number of Air

The prandtl number of air is around 0.7 as many other gases at 1 atm.
The Prandtl Number is a dimensionless number approaching the proportion of momentum diffusivity and thermal diffusivity.
Prandtl number equation is defined as:

where:
ν is the kinematic viscosity, ν = μ / ρ.
μ is dynamic viscosity, (SI units: Pa s = N s/m2).
ρ is density, (SI units: kg/m3).
α is the thermal diffusivity, α = k / (ρ cp).
k is thermal conductivity, (SI units: W/m·K)
cp is specific heat, (SI units: J/kg·K)
ρ is density, (SI units: kg/m3).
The values of μ, cp and k are acknowledged to change with temperature consequently the Prandtl number will change with temperature.
The values of μ, cp and k are only very weak functions of pressure so the Prandtl number presumed independent of pressure.

## Prandtl Number of Air

### Prandtl Number of Dry air at 1 atm pressure:

Temp, CTemp, FTemp, KPrandtl
Number, Pr
-193.15-315.6780mix
-183.15-297.67900.7960
-173.15-279.671000.7860
-153.15-243.671200.7730
-133.15-207.671400.7630
-113.15-171.671600.7540
-93.15-135.671800.7450
-73.15-99.672000.7380
-33.15-27.672400.7240
6.8544.332800.7100
26.8580.333000.7050
76.85170.333500.6990
126.85260.334000.6940
176.85350.334500.6910
226.85440.335000.6890
326.85620.336000.6900
426.85800.337000.6960
526.85980.338000.7050
626.851160.339000.7090
726.851340.3310000.7110

Note: For ideal gases, the properties cp, k, m, and Pr are independent of pressure.

### Prandtl number of air (dry Air) Table at temperature between 70 deg C and 2000 deg C :

Temp, CTemp, FTemp, KPrandtl
Number, Pr
70158343.150.7177
80176353.150.7154
90194363.150.7132
100212373.150.7111
120248393.150.7073
140284413.150.7041
160320433.150.7014
180356453.150.6992
200392473.150.6974
250482523.150.6946
300572573.150.6935
350662623.150.6937
400752673.150.6948
450842723.150.6965
500932773.150.6986
6001112873.150.7037
7001292973.150.7092
80014721073.150.7149
90016521173.150.7206
100018321273.150.7260
150027321773.150.7478
200036322273.150.7539

Note: For ideal gases, the properties cp, k, m, and Pr are independent of pressure.

## Prandtl Number of Air @ Different Pressure

Temp, CTemp, F10 bar30 bar50 bar70 bar100 bar
-193.15-315.672.322.372.422.482.57
-183.15-297.671.771.791.821.851.91
-173.15-279.671.541.531.531.531.55
-153.15-243.670.891.651.481.41.34
-133.15-207.670.821.22.142.071.52
-113.15-171.670.780.921.131.371.72
-93.15-135.670.7630.830.9321.071.25
-73.15-99.670.7490.7880.8410.91
-33.15-27.670.7290.7460.7670.80.82
6.8544.330.7130.7210.7310.7420.76
26.8580.330.7080.7150.7210.7280.742
76.85170.330.6990.7030.7070.7110.716
126.85260.330.6940.6960.6980.70.704
176.85350.330.6910.6920.6930.6940.696
226.85440.330.6890.6890.690.690.691
326.85620.330.690.6890.6890.6890.69
426.85800.330.6950.6950.6950.6950.695
526.85980.330.7040.7040.7030.7030.702
626.851160.330.7080.7080.7080.7080.708
726.851340.330.7110.7110.710.710.709

## Prandtl Number of Air @ Different Temperature

280 K300K500K1000 K
10.710.7050.6890.711
50.7110.7070.6890.711
100.7130.7080.6890.711
200.7170.7120.6890.711
300.7210.7150.6890.711
400.7260.7170.690.71
500.7310.7210.690.71
600.7370.7250.690.71
700.7420.7280.690.71
800.750.7320.6910.709
900.750.7370.6910.709
1000.760.7420.6910.709

## Prandtl number of Humid air

Prandtl number of moist air with a relative humidity (RH) varying between 0% and 100%

References: