Mass diffusivity of Gasoline Vapour in Air

[JohnMoffat]

Can anyone tell me the mass diffusivity of gasoline (C7.2 H12.6) vapour in Air as a function of temperature ?

I know this comes accorrss as a bit Lazy, and if I spend some time in a Library I could probably find it - but ...

 

[TD2K]

Don't have any data on C7 but the following is from the CRC Handbook of Tables for Applied Engineering Science, 2nd edition, page 546

Diffusion coefficients are in ft2/hr at 0C and 25C and 1 atm.

Benzene, 0.291 and 0.341
n-butyl alcohol, 0.272 and 0.348
Xylene, 0.228 and 0.271
n-octane, 0.195 and 0.232

n-octane is reasonably close I would expect to C7, depending how accurate you need it. Sorry, that's all the data I have.

 

[25362]

Diffusion coefficients of gases depend on average molecular speeds, thus are related to temperature. They are apparently proportional to T[sup]n[/sup]/P. Where T is absolute temperature, P total pressure, and n seems to vary.

Tabulated values of n for air, helium and hydrogen, 1.6-1.75; for CO2 and water vapor, around 2.1; for ammonia vapors, 2.2 . Following Gilliland (1934) n = 1.5; Perry VI, n = 1.75.