Gas Viscosity Calculator
Enter temperature to compute gas dynamic (absolute) viscosity.
Units in gas viscosity calculation:
The viscosity on this page is the dynamic (absolute) viscosity. Dynamic viscosity of gases is primarily a function of temperature. This variation is provided in Crane (1988) as a graph for hydrocarbon vapors and natural gases, and as an equation for other common gases. The impact of pressure is minor and the viscosity correction for pressure is less than 10% for the gases in our calculation for pressures up to 500 psi (34.5 bar) (Crane, 1988).
Hydrocarbon vapors and natural gases
μ = μo*(a/b)*(T/To)3/2
a = 0.555To + C
The following table gives the values of Sutherland's constant and the reference temperature and viscosity for the gases used in the LMNO Engineering calculation. Values of Sutherland's constant are from Crane (1988, p.A-5). The reference temperatures and viscosities were selected from CRC (1984, pp.F-42-44).
Validity of gas viscosity equation
For hydrocarbon vapors and natural gases, input temperature T is restricted to the
For other gases, input temperature must be at least absolute zero (0 K).
If the input temperature is outside the valid range, an error message is printed and viscosity is not computed.
The impact of pressure is minor, and the viscosity correction for pressure is less than 10% for the gases in our calculation for pressures up to 500 psi (34.5 bar) (Crane, 1988).
References for gas viscosity
Crane Company. 1988. Flow of fluids through valves, fittings, and pipe. Technical Paper No. 410 (TP 410).
© 2003-2015 LMNO Engineering, Research, and Software, Ltd. (All Rights Reserved)
August 25, 2015: Made text fields show 8 significant figures rather than 16. Calculation still uses double precision internally.
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